NEWS
author wenzelm
Thu Apr 03 21:23:36 2008 +0200 (2008-04-03)
changeset 26545 6e1aef001b3b
parent 26513 6f306c8c2c54
child 26562 9d25ef112cf6
permissions -rw-r--r--
output: canonical argument order (as opposed to write);
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Syntax: symbol \<chi> is now considered a letter.  Potential
    10 INCOMPATIBILITY in identifier syntax etc.
    11 
    12 * Outer syntax: string tokens may contain arbitrary character codes
    13 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
    14 "foo_bar".
    15 
    16 * Outer syntax: string tokens no longer admit escaped white space,
    17 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
    18 white space directly.
    19 
    20 * Theory loader: use_thy (and similar operations) no longer set the
    21 implicit ML context, which was occasionally hard to predict and in
    22 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
    23 provides a proper context already.
    24 
    25 * Theory loader: old-style ML proof scripts being *attached* to a thy
    26 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
    27 'use' within a theory file will do the job.
    28 
    29 
    30 *** Pure ***
    31 
    32 * Eliminated destructive theorem database, simpset, claset, and
    33 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
    34 update of theories within ML code.
    35 
    36 * Commands 'use' and 'ML' are now purely functional, operating on
    37 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
    38 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
    39 INCOMPATIBILITY.
    40 
    41 * Eliminated theory ProtoPure.  Potential INCOMPATIBILITY.
    42 
    43 * Command 'setup': discontinued implicit version.
    44 
    45 * Instantiation target allows for simultaneous specification of class
    46 instance operations together with an instantiation proof.
    47 Type-checking phase allows to refer to class operations uniformly.
    48 See HOL/Complex/Complex.thy for an Isar example and
    49 HOL/Library/Eval.thy for an ML example.
    50 
    51 * Indexing of literal facts: be more serious about including only
    52 facts from the visible specification/proof context, but not the
    53 background context (locale etc.).  Affects `prop` notation and method
    54 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
    55 situations.
    56 
    57 
    58 *** HOL ***
    59 
    60 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
    61 
    62 * Class finite no longer treats UNIV as class parameter.  Use class enum from
    63 theory Library/Enum instead to achieve a similar effect.  INCOMPATIBILITY.
    64 
    65 * Theory List: rule list_induct2 now has explicitly named cases "Nil" and "Cons".
    66 INCOMPATIBILITY.
    67 
    68 * HOL (and FOL): renamed variables in rules imp_elim and swap.
    69 Potential INCOMPATIBILITY.
    70 
    71 * Theory Product_Type: duplicated lemmas split_Pair_apply and injective_fst_snd
    72 removed, use split_eta and prod_eqI instead.  Renamed upd_fst to apfst and upd_snd
    73 to apsnd.  INCOMPATIBILITY.
    74 
    75 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
    76 the same name in theory Orderings:
    77 
    78   less_trans
    79   less_linear
    80   le_imp_less_or_eq
    81   le_less_trans
    82   less_le_trans
    83   less_not_sym
    84   less_asym
    85 
    86 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
    87 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
    88 and different variable names.
    89 
    90 * Library/Option_ord.thy: Canonical order on option type.
    91 
    92 * Library/RBT.thy: New theory of red-black trees, an efficient
    93 implementation of finite maps.
    94 
    95 * Library/Countable.thy: Type class for countable types.
    96 
    97 * Theory Int: The representation of numerals has changed.  The infix
    98 operator BIT and the bit datatype with constructors B0 and B1 have
    99 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
   100 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
   101 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
   102 accordingly.
   103 
   104 * Theory Nat: definition of <= and < on natural numbers no longer
   105 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
   106 le_def and less_def have disappeared.  Consider lemmas not_less
   107 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
   108 
   109 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
   110 (whose purpose mainly is for various fold_set functionals) have been
   111 abandoned in favour of the existing algebraic classes
   112 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
   113 lower_semilattice (resp. upper_semilattice) and linorder.
   114 INCOMPATIBILITY.
   115 
   116 * Theory Transitive_Closure: induct and cases rules now declare proper
   117 case_names ("base" and "step").  INCOMPATIBILITY.
   118 
   119 * Theorem Inductive.lfp_ordinal_induct generalized to complete
   120 lattices.  The form set-specific version is available as
   121 Inductive.lfp_ordinal_induct_set.
   122 
   123 * Theorems "power.simps" renamed to "power_int.simps".
   124 
   125 * Class semiring_div provides basic abstract properties of semirings
   126 with division and modulo operations.  Subsumes former class dvd_mod.
   127 
   128 * Merged theories IntDef, Numeral and IntArith into unified theory
   129 Int.  INCOMPATIBILITY.
   130 
   131 * Theory Library/Code_Index: type "index" now represents natural
   132 numbers rather than integers.  INCOMPATIBILITY.
   133 
   134 * New class "uminus" with operation "uminus" (split of from class
   135 "minus" which now only has operation "minus", binary).
   136 INCOMPATIBILITY.
   137 
   138 * New primrec package.  Specification syntax conforms in style to
   139 definition/function/....  No separate induction rule is provided.  The
   140 "primrec" command distinguishes old-style and new-style specifications
   141 by syntax.  The former primrec package is now named OldPrimrecPackage.
   142 When adjusting theories, beware: constants stemming from new-style
   143 primrec specifications have authentic syntax.
   144 
   145 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
   146 
   147 * Library/ListVector: new theory of arithmetic vector operations.
   148 
   149 * Library/Order_Relation: new theory of various orderings as sets of pairs.
   150   Defines preorders, partial orders, linear orders and well-orders
   151   on sets and on types.
   152 
   153 * Constants "card", "internal_split", "option_map" now with authentic
   154 syntax.  INCOMPATIBILITY.
   155 
   156 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
   157 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
   158 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
   159 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
   160 Sup_set_def, le_def, less_def, option_map_def now with object
   161 equality.  INCOMPATIBILITY.
   162 
   163 * Method "induction_scheme" derives user-specified induction rules
   164 from wellfounded induction and completeness of patterns. This factors
   165 out some operations that are done internally by the function package
   166 and makes them available separately. See "HOL/ex/Induction_Scheme.thy"
   167 for examples,
   168 
   169 * Records. Removed K_record, and replaced it by pure lambda term
   170 %x. c. The simplifier setup is now more robust against eta expansion.
   171 INCOMPATIBILITY: in cases explicitly referring to K_record.
   172 
   173 * Metis prover is now an order of magnitude faster, and also works
   174 with multithreading.
   175 
   176 * Sledgehammer no longer produces structured proofs by default. To enable, 
   177 declare [[sledgehammer_full = true]]. Attributes reconstruction_modulus,  
   178 reconstruction_sorts renamed sledgehammer_modulus, sledgehammer_sorts. 
   179 INCOMPATIBILITY.
   180 
   181 *** ZF ***
   182 
   183 * Renamed theories:
   184 
   185   Datatype.thy  -> Datatype_ZF.thy
   186   Inductive.thy -> Inductive_ZF.thy
   187   Int.thy       -> Int_ZF.thy
   188   IntDiv.thy    -> IntDiv_ZF.thy
   189   Nat.thy       -> Nat_ZF.thy
   190   List.thy      -> List_ZF.thy
   191   Main.thy      -> Main_ZF.thy
   192 
   193  This is to allow to load both ZF and HOL in the same session.
   194 
   195  INCOMPATIBILITY: ZF theories that import individual theories below
   196  Main might need to be adapted. For compatibility, a new 
   197  "theory Main imports Main_ZF begin end" is provided, so if you just
   198  imported "Main", no changes are needed.
   199 
   200 
   201 *** ML ***
   202 
   203 * Functor NamedThmsFun: data is available to the user as dynamic fact
   204 (of the same name).
   205 
   206 * Removed obsolete "use_legacy_bindings" function.  INCOMPATIBILITY.
   207 
   208 * ML within Isar: antiquotation @{const name} or @{const
   209 name(typargs)} produces statically-checked Const term.
   210 
   211 * The ``print mode'' is now a thread-local value derived from a global
   212 template (the former print_mode reference), thus access becomes
   213 non-critical.  The global print_mode reference is for session
   214 management only; user-code should use print_mode_value,
   215 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
   216 
   217 * system/system_out provides a robust way to invoke external shell
   218 commands, with propagation of interrupts (after Poly/ML 5.2).  Do not
   219 use OS.Process.system etc. directly.
   220 
   221 
   222 *** System ***
   223 
   224 * System: removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the
   225 documented way of changing the user's settings is via
   226 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
   227 script.
   228 
   229 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
   230 in accordance with Proof General 3.7, which prefers GNU emacs.
   231 
   232 * Multithreading.max_threads := 0 refers to the number of actual CPU
   233 cores of the underlying machine, which is a good starting point for
   234 optimal performance tuning.  The corresponding usedir option -M allows
   235 "max" as an alias for "0".  WARNING: does not work on certain versions
   236 of Mac OS (with Poly/ML 5.1).
   237 
   238 * isatool tty runs Isabelle process with plain tty interaction;
   239 optional line editor may be specified via ISABELLE_LINE_EDITOR
   240 setting, the default settings attempt to locate "ledit" and "rlwrap".
   241 
   242 * isatool browser now works with Cygwin as well, using general
   243 "javapath" function defined in Isabelle process environment.
   244 
   245 * isabelle-process: non-ML sessions are run with "nice", to prevent
   246 Isabelle from flooding interactive front-ends (notably ProofGeneral /
   247 XEmacs).
   248 
   249 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   250 provides general wrapper for managing an Isabelle process in a robust
   251 fashion, with ``cooked'' output from stdin/stderr.
   252 
   253 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   254 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   255 
   256 
   257 
   258 New in Isabelle2007 (November 2007)
   259 -----------------------------------
   260 
   261 *** General ***
   262 
   263 * More uniform information about legacy features, notably a
   264 warning/error of "Legacy feature: ...", depending on the state of the
   265 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   266 legacy features will disappear eventually.
   267 
   268 * Theory syntax: the header format ``theory A = B + C:'' has been
   269 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   270 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   271 
   272 * Theory syntax: the old non-Isar theory file format has been
   273 discontinued altogether.  Note that ML proof scripts may still be used
   274 with Isar theories; migration is usually quite simple with the ML
   275 function use_legacy_bindings.  INCOMPATIBILITY.
   276 
   277 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   278 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   279 quotes.
   280 
   281 * Theory loader: be more serious about observing the static theory
   282 header specifications (including optional directories), but not the
   283 accidental file locations of previously successful loads.  The strict
   284 update policy of former update_thy is now already performed by
   285 use_thy, so the former has been removed; use_thys updates several
   286 theories simultaneously, just as 'imports' within a theory header
   287 specification, but without merging the results.  Potential
   288 INCOMPATIBILITY: may need to refine theory headers and commands
   289 ROOT.ML which depend on load order.
   290 
   291 * Theory loader: optional support for content-based file
   292 identification, instead of the traditional scheme of full physical
   293 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   294 (cf. the system manual).  The new scheme allows to work with
   295 non-finished theories in persistent session images, such that source
   296 files may be moved later on without requiring reloads.
   297 
   298 * Theory loader: old-style ML proof scripts being *attached* to a thy
   299 file (with the same base name as the theory) are considered a legacy
   300 feature, which will disappear eventually. Even now, the theory loader
   301 no longer maintains dependencies on such files.
   302 
   303 * Syntax: the scope for resolving ambiguities via type-inference is
   304 now limited to individual terms, instead of whole simultaneous
   305 specifications as before. This greatly reduces the complexity of the
   306 syntax module and improves flexibility by separating parsing and
   307 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
   308 'fixes' etc.) are required in rare situations.
   309 
   310 * Syntax: constants introduced by new-style packages ('definition',
   311 'abbreviation' etc.) are passed through the syntax module in
   312 ``authentic mode''. This means that associated mixfix annotations
   313 really stick to such constants, independently of potential name space
   314 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
   315 trees are represented slightly differently, may need to adapt syntax
   316 translations accordingly. Use CONST marker in 'translations' and
   317 @{const_syntax} antiquotation in 'parse_translation' etc.
   318 
   319 * Legacy goal package: reduced interface to the bare minimum required
   320 to keep existing proof scripts running.  Most other user-level
   321 functions are now part of the OldGoals structure, which is *not* open
   322 by default (consider isatool expandshort before open OldGoals).
   323 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   324 these tend to cause confusion about the actual goal (!) context being
   325 used here, which is not necessarily the same as the_context().
   326 
   327 * Command 'find_theorems': supports "*" wild-card in "name:"
   328 criterion; "with_dups" option.  Certain ProofGeneral versions might
   329 support a specific search form (see ProofGeneral/CHANGES).
   330 
   331 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   332 by default, which means that "prems" (and also "fixed variables") are
   333 suppressed from proof state output.  Note that the ProofGeneral
   334 settings mechanism allows to change and save options persistently, but
   335 older versions of Isabelle will fail to start up if a negative prems
   336 limit is imposed.
   337 
   338 * Local theory targets may be specified by non-nested blocks of
   339 ``context/locale/class ... begin'' followed by ``end''.  The body may
   340 contain definitions, theorems etc., including any derived mechanism
   341 that has been implemented on top of these primitives.  This concept
   342 generalizes the existing ``theorem (in ...)'' towards more versatility
   343 and scalability.
   344 
   345 * Proof General interface: proper undo of final 'end' command;
   346 discontinued Isabelle/classic mode (ML proof scripts).
   347 
   348 
   349 *** Document preparation ***
   350 
   351 * Added antiquotation @{theory name} which prints the given name,
   352 after checking that it refers to a valid ancestor theory in the
   353 current context.
   354 
   355 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   356 check the given source text as ML type/structure, printing verbatim.
   357 
   358 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   359 "c args == rhs" given in the current context.  (Any number of
   360 arguments may be given on the LHS.)
   361 
   362 
   363 *** Pure ***
   364 
   365 * The 'class' package offers a combination of axclass and locale to
   366 achieve Haskell-like type classes in Isabelle.  Definitions and
   367 theorems within a class context produce both relative results (with
   368 implicit parameters according to the locale context), and polymorphic
   369 constants with qualified polymorphism (according to the class
   370 context).  Within the body context of a 'class' target, a separate
   371 syntax layer ("user space type system") takes care of converting
   372 between global polymorphic consts and internal locale representation.
   373 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   374 "isatool doc classes" provides a tutorial.
   375 
   376 * Generic code generator framework allows to generate executable
   377 code for ML and Haskell (including Isabelle classes).  A short usage
   378 sketch:
   379 
   380     internal compilation:
   381         export_code <list of constants (term syntax)> in SML
   382     writing SML code to a file:
   383         export_code <list of constants (term syntax)> in SML <filename>
   384     writing OCaml code to a file:
   385         export_code <list of constants (term syntax)> in OCaml <filename>
   386     writing Haskell code to a bunch of files:
   387         export_code <list of constants (term syntax)> in Haskell <filename>
   388 
   389     evaluating closed propositions to True/False using code generation:
   390         method ``eval''
   391 
   392 Reasonable default setup of framework in HOL.
   393 
   394 Theorem attributs for selecting and transforming function equations theorems:
   395 
   396     [code fun]:        select a theorem as function equation for a specific constant
   397     [code fun del]:    deselect a theorem as function equation for a specific constant
   398     [code inline]:     select an equation theorem for unfolding (inlining) in place
   399     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   400 
   401 User-defined serializations (target in {SML, OCaml, Haskell}):
   402 
   403     code_const <and-list of constants (term syntax)>
   404       {(target) <and-list of const target syntax>}+
   405 
   406     code_type <and-list of type constructors>
   407       {(target) <and-list of type target syntax>}+
   408 
   409     code_instance <and-list of instances>
   410       {(target)}+
   411         where instance ::= <type constructor> :: <class>
   412 
   413     code_class <and_list of classes>
   414       {(target) <and-list of class target syntax>}+
   415         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   416 
   417 code_instance and code_class only are effective to target Haskell.
   418 
   419 For example usage see src/HOL/ex/Codegenerator.thy and
   420 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   421 generation from Isabelle/HOL theories is available via "isatool doc
   422 codegen".
   423 
   424 * Code generator: consts in 'consts_code' Isar commands are now
   425 referred to by usual term syntax (including optional type
   426 annotations).
   427 
   428 * Command 'no_translations' removes translation rules from theory
   429 syntax.
   430 
   431 * Overloaded definitions are now actually checked for acyclic
   432 dependencies.  The overloading scheme is slightly more general than
   433 that of Haskell98, although Isabelle does not demand an exact
   434 correspondence to type class and instance declarations.
   435 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   436 exotic versions of overloading -- at the discretion of the user!
   437 
   438 Polymorphic constants are represented via type arguments, i.e. the
   439 instantiation that matches an instance against the most general
   440 declaration given in the signature.  For example, with the declaration
   441 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   442 as c(nat).  Overloading is essentially simultaneous structural
   443 recursion over such type arguments.  Incomplete specification patterns
   444 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   445 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   446 Command 'print_theory' outputs the normalized system of recursive
   447 equations, see section "definitions".
   448 
   449 * Configuration options are maintained within the theory or proof
   450 context (with name and type bool/int/string), providing a very simple
   451 interface to a poor-man's version of general context data.  Tools may
   452 declare options in ML (e.g. using Attrib.config_int) and then refer to
   453 these values using Config.get etc.  Users may change options via an
   454 associated attribute of the same name.  This form of context
   455 declaration works particularly well with commands 'declare' or
   456 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   457 very easy to avoid global references, which would not observe Isar
   458 toplevel undo/redo and fail to work with multithreading.
   459 
   460 Various global ML references of Pure and HOL have been turned into
   461 configuration options:
   462 
   463   Unify.search_bound		unify_search_bound
   464   Unify.trace_bound		unify_trace_bound
   465   Unify.trace_simp		unify_trace_simp
   466   Unify.trace_types		unify_trace_types
   467   Simplifier.simp_depth_limit	simp_depth_limit
   468   Blast.depth_limit		blast_depth_limit
   469   DatatypeProp.dtK		datatype_distinctness_limit
   470   fast_arith_neq_limit  	fast_arith_neq_limit
   471   fast_arith_split_limit	fast_arith_split_limit
   472 
   473 * Named collections of theorems may be easily installed as context
   474 data using the functor NamedThmsFun (see also
   475 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   476 attributes; there is also a toplevel print command.  This facility is
   477 just a common case of general context data, which is the preferred way
   478 for anything more complex than just a list of facts in canonical
   479 order.
   480 
   481 * Isar: command 'declaration' augments a local theory by generic
   482 declaration functions written in ML.  This enables arbitrary content
   483 being added to the context, depending on a morphism that tells the
   484 difference of the original declaration context wrt. the application
   485 context encountered later on.
   486 
   487 * Isar: proper interfaces for simplification procedures.  Command
   488 'simproc_setup' declares named simprocs (with match patterns, and body
   489 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   490 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   491 
   492 * Isar: an extra pair of brackets around attribute declarations
   493 abbreviates a theorem reference involving an internal dummy fact,
   494 which will be ignored later --- only the effect of the attribute on
   495 the background context will persist.  This form of in-place
   496 declarations is particularly useful with commands like 'declare' and
   497 'using', for example ``have A using [[simproc a]] by simp''.
   498 
   499 * Isar: method "assumption" (and implicit closing of subproofs) now
   500 takes simple non-atomic goal assumptions into account: after applying
   501 an assumption as a rule the resulting subgoals are solved by atomic
   502 assumption steps.  This is particularly useful to finish 'obtain'
   503 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   504 without referring to the original premise "!!x. P x ==> thesis" in the
   505 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   506 more permissive.
   507 
   508 * Isar: implicit use of prems from the Isar proof context is
   509 considered a legacy feature.  Common applications like ``have A .''
   510 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   511 referencing facts explicitly here improves readability and
   512 maintainability of proof texts.
   513 
   514 * Isar: improper proof element 'guess' is like 'obtain', but derives
   515 the obtained context from the course of reasoning!  For example:
   516 
   517   assume "EX x y. A x & B y"   -- "any previous fact"
   518   then guess x and y by clarify
   519 
   520 This technique is potentially adventurous, depending on the facts and
   521 proof tools being involved here.
   522 
   523 * Isar: known facts from the proof context may be specified as literal
   524 propositions, using ASCII back-quote syntax.  This works wherever
   525 named facts used to be allowed so far, in proof commands, proof
   526 methods, attributes etc.  Literal facts are retrieved from the context
   527 according to unification of type and term parameters.  For example,
   528 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   529 theorems in the current context, then these are valid literal facts:
   530 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   531 
   532 There is also a proof method "fact" which does the same composition
   533 for explicit goal states, e.g. the following proof texts coincide with
   534 certain special cases of literal facts:
   535 
   536   have "A" by fact                 ==  note `A`
   537   have "A ==> B" by fact           ==  note `A ==> B`
   538   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   539   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   540 
   541 * Isar: ":" (colon) is no longer a symbolic identifier character in
   542 outer syntax.  Thus symbolic identifiers may be used without
   543 additional white space in declarations like this: ``assume *: A''.
   544 
   545 * Isar: 'print_facts' prints all local facts of the current context,
   546 both named and unnamed ones.
   547 
   548 * Isar: 'def' now admits simultaneous definitions, e.g.:
   549 
   550   def x == "t" and y == "u"
   551 
   552 * Isar: added command 'unfolding', which is structurally similar to
   553 'using', but affects both the goal state and facts by unfolding given
   554 rewrite rules.  Thus many occurrences of the 'unfold' method or
   555 'unfolded' attribute may be replaced by first-class proof text.
   556 
   557 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   558 and command 'unfolding' now all support object-level equalities
   559 (potentially conditional).  The underlying notion of rewrite rule is
   560 analogous to the 'rule_format' attribute, but *not* that of the
   561 Simplifier (which is usually more generous).
   562 
   563 * Isar: the new attribute [rotated n] (default n = 1) rotates the
   564 premises of a theorem by n. Useful in conjunction with drule.
   565 
   566 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   567 method expression within a sandbox consisting of the first N
   568 sub-goals, which need to exist.  For example, ``simp_all [3]''
   569 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   570 simplifies all new goals that emerge from applying rule foo to the
   571 originally first one.
   572 
   573 * Isar: schematic goals are no longer restricted to higher-order
   574 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   575 expected.
   576 
   577 * Isar: the conclusion of a long theorem statement is now either
   578 'shows' (a simultaneous conjunction, as before), or 'obtains'
   579 (essentially a disjunction of cases with local parameters and
   580 assumptions).  The latter allows to express general elimination rules
   581 adequately; in this notation common elimination rules look like this:
   582 
   583   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   584     assumes "EX x. P x"
   585     obtains x where "P x"
   586 
   587   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   588     assumes "A & B"
   589     obtains A and B
   590 
   591   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   592     assumes "A | B"
   593     obtains
   594       A
   595     | B
   596 
   597 The subsequent classical rules even refer to the formal "thesis"
   598 explicitly:
   599 
   600   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   601     obtains "~ thesis"
   602 
   603   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   604     obtains "thesis ==> something"
   605 
   606 The actual proof of an 'obtains' statement is analogous to that of the
   607 Isar proof element 'obtain', only that there may be several cases.
   608 Optional case names may be specified in parentheses; these will be
   609 available both in the present proof and as annotations in the
   610 resulting rule, for later use with the 'cases' method (cf. attribute
   611 case_names).
   612 
   613 * Isar: the assumptions of a long theorem statement are available as
   614 "assms" fact in the proof context.  This is more appropriate than the
   615 (historical) "prems", which refers to all assumptions of the current
   616 context, including those from the target locale, proof body etc.
   617 
   618 * Isar: 'print_statement' prints theorems from the current theory or
   619 proof context in long statement form, according to the syntax of a
   620 top-level lemma.
   621 
   622 * Isar: 'obtain' takes an optional case name for the local context
   623 introduction rule (default "that").
   624 
   625 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   626 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   627 to occur.
   628 
   629 * Pure: syntax "CONST name" produces a fully internalized constant
   630 according to the current context.  This is particularly useful for
   631 syntax translations that should refer to internal constant
   632 representations independently of name spaces.
   633 
   634 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   635 instead of "FOO ". This allows multiple binder declarations to coexist
   636 in the same context.  INCOMPATIBILITY.
   637 
   638 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   639 primitive that also works in a locale context (both for constants and
   640 fixed variables). Type declaration and internal syntactic representation
   641 of given constants retrieved from the context. Likewise, the
   642 'no_notation' command allows to remove given syntax annotations from the
   643 current context.
   644 
   645 * Isar/locales: new derived specification elements 'axiomatization',
   646 'definition', 'abbreviation', which support type-inference, admit
   647 object-level specifications (equality, equivalence).  See also the
   648 isar-ref manual.  Examples:
   649 
   650   axiomatization
   651     eq  (infix "===" 50) where
   652     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   653 
   654   definition "f x y = x + y + 1"
   655   definition g where "g x = f x x"
   656 
   657   abbreviation
   658     neq  (infix "=!=" 50) where
   659     "x =!= y == ~ (x === y)"
   660 
   661 These specifications may be also used in a locale context.  Then the
   662 constants being introduced depend on certain fixed parameters, and the
   663 constant name is qualified by the locale base name.  An internal
   664 abbreviation takes care for convenient input and output, making the
   665 parameters implicit and using the original short name.  See also
   666 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   667 entities from a monomorphic theory.
   668 
   669 Presently, abbreviations are only available 'in' a target locale, but
   670 not inherited by general import expressions.  Also note that
   671 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   672 'translations' in common applications.  The "no_abbrevs" print mode
   673 prevents folding of abbreviations in term output.
   674 
   675 Concrete syntax is attached to specified constants in internal form,
   676 independently of name spaces.  The parse tree representation is
   677 slightly different -- use 'notation' instead of raw 'syntax', and
   678 'translations' with explicit "CONST" markup to accommodate this.
   679 
   680 * Pure/Isar: unified syntax for new-style specification mechanisms
   681 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
   682 full type inference and dummy patterns ("_").  For example:
   683 
   684   definition "K x _ = x"
   685 
   686   inductive conj for A B
   687   where "A ==> B ==> conj A B"
   688 
   689 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   690 the current context.  Print mode "no_abbrevs" prevents inversion of
   691 abbreviations on output.
   692 
   693 * Isar/locales: improved parameter handling: use of locales "var" and
   694 "struct" no longer necessary; - parameter renamings are no longer
   695 required to be injective.  For example, this allows to define
   696 endomorphisms as locale endom = homom mult mult h.
   697 
   698 * Isar/locales: changed the way locales with predicates are defined.
   699 Instead of accumulating the specification, the imported expression is
   700 now an interpretation.  INCOMPATIBILITY: different normal form of
   701 locale expressions.  In particular, in interpretations of locales with
   702 predicates, goals repesenting already interpreted fragments are not
   703 removed automatically.  Use methods `intro_locales' and
   704 `unfold_locales'; see below.
   705 
   706 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   707 provide backward reasoning on locales predicates.  The methods are
   708 aware of interpretations and discharge corresponding goals.
   709 `intro_locales' is less aggressive then `unfold_locales' and does not
   710 unfold predicates to assumptions.
   711 
   712 * Isar/locales: the order in which locale fragments are accumulated
   713 has changed.  This enables to override declarations from fragments due
   714 to interpretations -- for example, unwanted simp rules.
   715 
   716 * Isar/locales: interpretation in theories and proof contexts has been
   717 extended.  One may now specify (and prove) equations, which are
   718 unfolded in interpreted theorems.  This is useful for replacing
   719 defined concepts (constants depending on locale parameters) by
   720 concepts already existing in the target context.  Example:
   721 
   722   interpretation partial_order ["op <= :: [int, int] => bool"]
   723     where "partial_order.less (op <=) (x::int) y = (x < y)"
   724 
   725 Typically, the constant `partial_order.less' is created by a
   726 definition specification element in the context of locale
   727 partial_order.
   728 
   729 * Method "induct": improved internal context management to support
   730 local fixes and defines on-the-fly. Thus explicit meta-level
   731 connectives !!  and ==> are rarely required anymore in inductive goals
   732 (using object-logic connectives for this purpose has been long
   733 obsolete anyway). Common proof patterns are explained in
   734 src/HOL/Induct/Common_Patterns.thy, see also
   735 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
   736 examples.
   737 
   738 * Method "induct": improved handling of simultaneous goals. Instead of
   739 introducing object-level conjunction, the statement is now split into
   740 several conclusions, while the corresponding symbolic cases are nested
   741 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
   742 see src/HOL/Induct/Common_Patterns.thy, for example.
   743 
   744 * Method "induct": mutual induction rules are now specified as a list
   745 of rule sharing the same induction cases. HOL packages usually provide
   746 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
   747 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
   748 mutual induction rules differently, i.e. like this:
   749 
   750   (induct rule: foo_bar.inducts)
   751   (induct set: foo bar)
   752   (induct pred: foo bar)
   753   (induct type: foo bar)
   754 
   755 The ML function ProjectRule.projections turns old-style rules into the
   756 new format.
   757 
   758 * Method "coinduct": dual of induction, see
   759 src/HOL/Library/Coinductive_List.thy for various examples.
   760 
   761 * Method "cases", "induct", "coinduct": the ``(open)'' option is
   762 considered a legacy feature.
   763 
   764 * Attribute "symmetric" produces result with standardized schematic
   765 variables (index 0).  Potential INCOMPATIBILITY.
   766 
   767 * Simplifier: by default the simplifier trace only shows top level
   768 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   769 default. Thus there is less danger of being flooded by the trace. The
   770 trace indicates where parts have been suppressed.
   771   
   772 * Provers/classical: removed obsolete classical version of elim_format
   773 attribute; classical elim/dest rules are now treated uniformly when
   774 manipulating the claset.
   775 
   776 * Provers/classical: stricter checks to ensure that supplied intro,
   777 dest and elim rules are well-formed; dest and elim rules must have at
   778 least one premise.
   779 
   780 * Provers/classical: attributes dest/elim/intro take an optional
   781 weight argument for the rule (just as the Pure versions).  Weights are
   782 ignored by automated tools, but determine the search order of single
   783 rule steps.
   784 
   785 * Syntax: input syntax now supports dummy variable binding "%_. b",
   786 where the body does not mention the bound variable.  Note that dummy
   787 patterns implicitly depend on their context of bounds, which makes
   788 "{_. _}" match any set comprehension as expected.  Potential
   789 INCOMPATIBILITY -- parse translations need to cope with syntactic
   790 constant "_idtdummy" in the binding position.
   791 
   792 * Syntax: removed obsolete syntactic constant "_K" and its associated
   793 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   794 for example "A -> B" => "Pi A (%_. B)".
   795 
   796 * Pure: 'class_deps' command visualizes the subclass relation, using
   797 the graph browser tool.
   798 
   799 * Pure: 'print_theory' now suppresses certain internal declarations by
   800 default; use '!' option for full details.
   801 
   802 
   803 *** HOL ***
   804 
   805 * Method "metis" proves goals by applying the Metis general-purpose
   806 resolution prover (see also http://gilith.com/software/metis/).
   807 Examples are in the directory MetisExamples.  WARNING: the
   808 Isabelle/HOL-Metis integration does not yet work properly with
   809 multi-threading.
   810   
   811 * Command 'sledgehammer' invokes external automatic theorem provers as
   812 background processes.  It generates calls to the "metis" method if
   813 successful. These can be pasted into the proof.  Users do not have to
   814 wait for the automatic provers to return.  WARNING: does not really
   815 work with multi-threading.
   816 
   817 * New "auto_quickcheck" feature tests outermost goal statements for
   818 potential counter-examples.  Controlled by ML references
   819 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
   820 5000 milliseconds).  Fails silently if statements is outside of
   821 executable fragment, or any other codgenerator problem occurs.
   822 
   823 * New constant "undefined" with axiom "undefined x = undefined".
   824 
   825 * Added class "HOL.eq", allowing for code generation with polymorphic
   826 equality.
   827 
   828 * Some renaming of class constants due to canonical name prefixing in
   829 the new 'class' package:
   830 
   831     HOL.abs ~> HOL.abs_class.abs
   832     HOL.divide ~> HOL.divide_class.divide
   833     0 ~> HOL.zero_class.zero
   834     1 ~> HOL.one_class.one
   835     op + ~> HOL.plus_class.plus
   836     op - ~> HOL.minus_class.minus
   837     uminus ~> HOL.minus_class.uminus
   838     op * ~> HOL.times_class.times
   839     op < ~> HOL.ord_class.less
   840     op <= > HOL.ord_class.less_eq
   841     Nat.power ~> Power.power_class.power
   842     Nat.size ~> Nat.size_class.size
   843     Numeral.number_of ~> Numeral.number_class.number_of
   844     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
   845     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
   846     Orderings.min ~> Orderings.ord_class.min
   847     Orderings.max ~> Orderings.ord_class.max
   848     Divides.op div ~> Divides.div_class.div
   849     Divides.op mod ~> Divides.div_class.mod
   850     Divides.op dvd ~> Divides.div_class.dvd
   851 
   852 INCOMPATIBILITY.  Adaptions may be required in the following cases:
   853 
   854 a) User-defined constants using any of the names "plus", "minus",
   855 "times", "less" or "less_eq". The standard syntax translations for
   856 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
   857 names.
   858 
   859 b) Variables named "plus", "minus", "times", "less", "less_eq"
   860 INCOMPATIBILITY: use more specific names.
   861 
   862 c) Permutative equations (e.g. "a + b = b + a")
   863 Since the change of names also changes the order of terms, permutative
   864 rewrite rules may get applied in a different order. Experience shows
   865 that this is rarely the case (only two adaptions in the whole Isabelle
   866 distribution).  INCOMPATIBILITY: rewrite proofs
   867 
   868 d) ML code directly refering to constant names
   869 This in general only affects hand-written proof tactics, simprocs and
   870 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
   871 Consider using @{const_name} antiquotation.
   872 
   873 * New class "default" with associated constant "default".
   874 
   875 * Function "sgn" is now overloaded and available on int, real, complex
   876 (and other numeric types), using class "sgn".  Two possible defs of
   877 sgn are given as equational assumptions in the classes sgn_if and
   878 sgn_div_norm; ordered_idom now also inherits from sgn_if.
   879 INCOMPATIBILITY.
   880 
   881 * Locale "partial_order" now unified with class "order" (cf. theory
   882 Orderings), added parameter "less".  INCOMPATIBILITY.
   883 
   884 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
   885 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
   886 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
   887 
   888 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
   889 changed order of proof goals in instance proofs.
   890 
   891 * The transitivity reasoner for partial and linear orders is set up
   892 for classes "order" and "linorder".  Instances of the reasoner are available
   893 in all contexts importing or interpreting the corresponding locales.
   894 Method "order" invokes the reasoner separately; the reasoner
   895 is also integrated with the Simplifier as a solver.  Diagnostic
   896 command 'print_orders' shows the available instances of the reasoner
   897 in the current context.
   898 
   899 * Localized monotonicity predicate in theory "Orderings"; integrated
   900 lemmas max_of_mono and min_of_mono with this predicate.
   901 INCOMPATIBILITY.
   902 
   903 * Formulation of theorem "dense" changed slightly due to integration
   904 with new class dense_linear_order.
   905 
   906 * Uniform lattice theory development in HOL.
   907 
   908     constants "meet" and "join" now named "inf" and "sup"
   909     constant "Meet" now named "Inf"
   910 
   911     classes "meet_semilorder" and "join_semilorder" now named
   912       "lower_semilattice" and "upper_semilattice"
   913     class "lorder" now named "lattice"
   914     class "comp_lat" now named "complete_lattice"
   915 
   916     Instantiation of lattice classes allows explicit definitions
   917     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
   918 
   919   INCOMPATIBILITY.  Theorem renames:
   920 
   921     meet_left_le            ~> inf_le1
   922     meet_right_le           ~> inf_le2
   923     join_left_le            ~> sup_ge1
   924     join_right_le           ~> sup_ge2
   925     meet_join_le            ~> inf_sup_ord
   926     le_meetI                ~> le_infI
   927     join_leI                ~> le_supI
   928     le_meet                 ~> le_inf_iff
   929     le_join                 ~> ge_sup_conv
   930     meet_idempotent         ~> inf_idem
   931     join_idempotent         ~> sup_idem
   932     meet_comm               ~> inf_commute
   933     join_comm               ~> sup_commute
   934     meet_leI1               ~> le_infI1
   935     meet_leI2               ~> le_infI2
   936     le_joinI1               ~> le_supI1
   937     le_joinI2               ~> le_supI2
   938     meet_assoc              ~> inf_assoc
   939     join_assoc              ~> sup_assoc
   940     meet_left_comm          ~> inf_left_commute
   941     meet_left_idempotent    ~> inf_left_idem
   942     join_left_comm          ~> sup_left_commute
   943     join_left_idempotent    ~> sup_left_idem
   944     meet_aci                ~> inf_aci
   945     join_aci                ~> sup_aci
   946     le_def_meet             ~> le_iff_inf
   947     le_def_join             ~> le_iff_sup
   948     join_absorp2            ~> sup_absorb2
   949     join_absorp1            ~> sup_absorb1
   950     meet_absorp1            ~> inf_absorb1
   951     meet_absorp2            ~> inf_absorb2
   952     meet_join_absorp        ~> inf_sup_absorb
   953     join_meet_absorp        ~> sup_inf_absorb
   954     distrib_join_le         ~> distrib_sup_le
   955     distrib_meet_le         ~> distrib_inf_le
   956 
   957     add_meet_distrib_left   ~> add_inf_distrib_left
   958     add_join_distrib_left   ~> add_sup_distrib_left
   959     is_join_neg_meet        ~> is_join_neg_inf
   960     is_meet_neg_join        ~> is_meet_neg_sup
   961     add_meet_distrib_right  ~> add_inf_distrib_right
   962     add_join_distrib_right  ~> add_sup_distrib_right
   963     add_meet_join_distribs  ~> add_sup_inf_distribs
   964     join_eq_neg_meet        ~> sup_eq_neg_inf
   965     meet_eq_neg_join        ~> inf_eq_neg_sup
   966     add_eq_meet_join        ~> add_eq_inf_sup
   967     meet_0_imp_0            ~> inf_0_imp_0
   968     join_0_imp_0            ~> sup_0_imp_0
   969     meet_0_eq_0             ~> inf_0_eq_0
   970     join_0_eq_0             ~> sup_0_eq_0
   971     neg_meet_eq_join        ~> neg_inf_eq_sup
   972     neg_join_eq_meet        ~> neg_sup_eq_inf
   973     join_eq_if              ~> sup_eq_if
   974 
   975     mono_meet               ~> mono_inf
   976     mono_join               ~> mono_sup
   977     meet_bool_eq            ~> inf_bool_eq
   978     join_bool_eq            ~> sup_bool_eq
   979     meet_fun_eq             ~> inf_fun_eq
   980     join_fun_eq             ~> sup_fun_eq
   981     meet_set_eq             ~> inf_set_eq
   982     join_set_eq             ~> sup_set_eq
   983     meet1_iff               ~> inf1_iff
   984     meet2_iff               ~> inf2_iff
   985     meet1I                  ~> inf1I
   986     meet2I                  ~> inf2I
   987     meet1D1                 ~> inf1D1
   988     meet2D1                 ~> inf2D1
   989     meet1D2                 ~> inf1D2
   990     meet2D2                 ~> inf2D2
   991     meet1E                  ~> inf1E
   992     meet2E                  ~> inf2E
   993     join1_iff               ~> sup1_iff
   994     join2_iff               ~> sup2_iff
   995     join1I1                 ~> sup1I1
   996     join2I1                 ~> sup2I1
   997     join1I1                 ~> sup1I1
   998     join2I2                 ~> sup1I2
   999     join1CI                 ~> sup1CI
  1000     join2CI                 ~> sup2CI
  1001     join1E                  ~> sup1E
  1002     join2E                  ~> sup2E
  1003 
  1004     is_meet_Meet            ~> is_meet_Inf
  1005     Meet_bool_def           ~> Inf_bool_def
  1006     Meet_fun_def            ~> Inf_fun_def
  1007     Meet_greatest           ~> Inf_greatest
  1008     Meet_lower              ~> Inf_lower
  1009     Meet_set_def            ~> Inf_set_def
  1010 
  1011     Sup_def                 ~> Sup_Inf
  1012     Sup_bool_eq             ~> Sup_bool_def
  1013     Sup_fun_eq              ~> Sup_fun_def
  1014     Sup_set_eq              ~> Sup_set_def
  1015 
  1016     listsp_meetI            ~> listsp_infI
  1017     listsp_meet_eq          ~> listsp_inf_eq
  1018 
  1019     meet_min                ~> inf_min
  1020     join_max                ~> sup_max
  1021 
  1022 * Added syntactic class "size"; overloaded constant "size" now has
  1023 type "'a::size ==> bool"
  1024 
  1025 * Internal reorganisation of `size' of datatypes: size theorems
  1026 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1027 simplification rules by default!); theorems "prod.size" now named
  1028 "*.size".
  1029 
  1030 * Class "div" now inherits from class "times" rather than "type".
  1031 INCOMPATIBILITY.
  1032 
  1033 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1034 Linorder etc.  have disappeared; operations defined in terms of
  1035 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1036 
  1037 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1038 
  1039 * HOL-Word: New extensive library and type for generic, fixed size
  1040 machine words, with arithemtic, bit-wise, shifting and rotating
  1041 operations, reflection into int, nat, and bool lists, automation for
  1042 linear arithmetic (by automatic reflection into nat or int), including
  1043 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1044 arithmetic type classes, supporting automatic simplification of
  1045 numerals on all operations.
  1046 
  1047 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1048 
  1049 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1050 
  1051 * Code generator library theories:
  1052   - Code_Integer represents HOL integers by big integer literals in target
  1053     languages.
  1054   - Code_Char represents HOL characters by character literals in target
  1055     languages.
  1056   - Code_Char_chr like Code_Char, but also offers treatment of character
  1057     codes; includes Code_Integer.
  1058   - Executable_Set allows to generate code for finite sets using lists.
  1059   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1060     denominator).
  1061   - Executable_Real implements a subset of real numbers, namly those
  1062     representable by rational numbers.
  1063   - Efficient_Nat implements natural numbers by integers, which in general will
  1064     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1065     includes Code_Integer.
  1066   - Code_Index provides an additional datatype index which is mapped to
  1067     target-language built-in integers.
  1068   - Code_Message provides an additional datatype message_string which is isomorphic to
  1069     strings; messages are mapped to target-language strings.
  1070 
  1071 * New package for inductive predicates
  1072 
  1073   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1074 
  1075     inductive
  1076       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1077       for z_1 :: U_1 and ... and z_n :: U_m
  1078     where
  1079       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1080     | ...
  1081 
  1082   with full support for type-inference, rather than
  1083 
  1084     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1085 
  1086     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1087     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1088 
  1089     inductive "s z_1 ... z_m"
  1090     intros
  1091       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1092       ...
  1093 
  1094   For backward compatibility, there is a wrapper allowing inductive
  1095   sets to be defined with the new package via
  1096 
  1097     inductive_set
  1098       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1099       for z_1 :: U_1 and ... and z_n :: U_m
  1100     where
  1101       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1102     | ...
  1103 
  1104   or
  1105 
  1106     inductive_set
  1107       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1108       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1109       for z_1 :: U_1 and ... and z_n :: U_m
  1110     where
  1111       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1112     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1113     | ...
  1114 
  1115   if the additional syntax "p ..." is required.
  1116 
  1117   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1118   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1119 
  1120   INCOMPATIBILITIES:
  1121 
  1122   - Since declaration and definition of inductive sets or predicates
  1123     is no longer separated, abbreviations involving the newly
  1124     introduced sets or predicates must be specified together with the
  1125     introduction rules after the 'where' keyword (see above), rather
  1126     than before the actual inductive definition.
  1127 
  1128   - The variables in induction and elimination rules are now
  1129     quantified in the order of their occurrence in the introduction
  1130     rules, rather than in alphabetical order. Since this may break
  1131     some proofs, these proofs either have to be repaired, e.g. by
  1132     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1133     statements of the form
  1134 
  1135       case (rule_i a_i_1 ... a_i_{k_i})
  1136 
  1137     or the old order of quantification has to be restored by explicitly adding
  1138     meta-level quantifiers in the introduction rules, i.e.
  1139 
  1140       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1141 
  1142   - The format of the elimination rules is now
  1143 
  1144       p z_1 ... z_m x_1 ... x_n ==>
  1145         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1146         ==> ... ==> P
  1147 
  1148     for predicates and
  1149 
  1150       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1151         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1152         ==> ... ==> P
  1153 
  1154     for sets rather than
  1155 
  1156       x : s z_1 ... z_m ==>
  1157         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1158         ==> ... ==> P
  1159 
  1160     This may require terms in goals to be expanded to n-tuples
  1161     (e.g. using case_tac or simplification with the split_paired_all
  1162     rule) before the above elimination rule is applicable.
  1163 
  1164   - The elimination or case analysis rules for (mutually) inductive
  1165     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1166     list of rules "p_1_..._p_k.elims" is no longer available.
  1167 
  1168 * New package "function"/"fun" for general recursive functions,
  1169 supporting mutual and nested recursion, definitions in local contexts,
  1170 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1171 for small examples, and the separate tutorial on the function
  1172 package. The old recdef "package" is still available as before, but
  1173 users are encouraged to use the new package.
  1174 
  1175 * Method "lexicographic_order" automatically synthesizes termination
  1176 relations as lexicographic combinations of size measures. 
  1177 
  1178 * Case-expressions allow arbitrary constructor-patterns (including
  1179 "_") and take their order into account, like in functional
  1180 programming.  Internally, this is translated into nested
  1181 case-expressions; missing cases are added and mapped to the predefined
  1182 constant "undefined". In complicated cases printing may no longer show
  1183 the original input but the internal form. Lambda-abstractions allow
  1184 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1185 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1186 variable.
  1187 
  1188 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1189 is an abbreviation for "of_nat :: nat => int". The simplification
  1190 rules for "of_nat" have been changed to work like "int" did
  1191 previously.  Potential INCOMPATIBILITY:
  1192   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1193   - of_nat_diff and of_nat_mult are no longer default simp rules
  1194 
  1195 * Method "algebra" solves polynomial equations over (semi)rings using
  1196 Groebner bases. The (semi)ring structure is defined by locales and the
  1197 tool setup depends on that generic context. Installing the method for
  1198 a specific type involves instantiating the locale and possibly adding
  1199 declarations for computation on the coefficients.  The method is
  1200 already instantiated for natural numbers and for the axiomatic class
  1201 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1202 CALCULEMUS 2007 for the general principles underlying this
  1203 architecture of context-aware proof-tools.
  1204 
  1205 * Method "ferrack" implements quantifier elimination over
  1206 special-purpose dense linear orders using locales (analogous to
  1207 "algebra"). The method is already installed for class
  1208 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1209 rat, etc.
  1210 
  1211 * Former constant "List.op @" now named "List.append".  Use ML
  1212 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1213 circumvent possible incompatibilities when working on ML level.
  1214 
  1215 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1216 
  1217 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1218 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1219 
  1220 * New syntax for Haskell-like list comprehension (input only), eg.
  1221 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1222 
  1223 * The special syntax for function "filter" has changed from [x :
  1224 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1225 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1226 
  1227 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1228 defined on nat only, as an abbreviation for [a..<Suc b]
  1229 INCOMPATIBILITY.
  1230 
  1231 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1232 
  1233 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1234 
  1235 * New lemma collection field_simps (an extension of ring_simps) for
  1236 manipulating (in)equations involving division. Multiplies with all
  1237 denominators that can be proved to be non-zero (in equations) or
  1238 positive/negative (in inequations).
  1239 
  1240 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1241 have been improved and renamed to ring_simps, group_simps and
  1242 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1243 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1244 
  1245 * Theory Library/Commutative_Ring: switched from recdef to function
  1246 package; constants add, mul, pow now curried.  Infix syntax for
  1247 algebraic operations.
  1248 
  1249 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1250 INCOMPATIBILITY.
  1251 
  1252 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1253 INCOMPATIBILITY.
  1254 
  1255 * HOL/records: generalised field-update to take a function on the
  1256 field rather than the new value: r(|A := x|) is translated to A_update
  1257 (K x) r The K-combinator that is internally used is called K_record.
  1258 INCOMPATIBILITY: Usage of the plain update functions has to be
  1259 adapted.
  1260  
  1261 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1262 * x = 0, which are required for a semiring.  Richer structures do not
  1263 inherit from semiring_0 anymore, because this property is a theorem
  1264 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1265 there is more to prove, but this is mostly trivial.
  1266 
  1267 * Class "recpower" is generalized to arbitrary monoids, not just
  1268 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1269 commutativity or semiring properties additionally.
  1270 
  1271 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1272 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1273 better use 'abbreviation'.
  1274 
  1275 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1276 
  1277 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1278 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1279 significant changes for setting up numeral syntax for types:
  1280   - New constants Numeral.pred and Numeral.succ instead
  1281       of former Numeral.bin_pred and Numeral.bin_succ.
  1282   - Use integer operations instead of bin_add, bin_mult and so on.
  1283   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1284   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1285 
  1286 See src/HOL/Integ/IntArith.thy for an example setup.
  1287 
  1288 * Command 'normal_form' computes the normal form of a term that may
  1289 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1290 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1291 heavy-duty computations because the functions are compiled to ML
  1292 first.  Correspondingly, a method "normalization" is provided.  See
  1293 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1294 
  1295 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1296 25 like -->); output depends on the "iff" print_mode, the default is
  1297 "A = B" (with priority 50).
  1298 
  1299 * Relations less (<) and less_eq (<=) are also available on type bool.
  1300 Modified syntax to disallow nesting without explicit parentheses,
  1301 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1302 INCOMPATIBILITY.
  1303 
  1304 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1305 
  1306 * Relation composition operator "op O" now has precedence 75 and binds
  1307 stronger than union and intersection. INCOMPATIBILITY.
  1308 
  1309 * The old set interval syntax "{m..n(}" (and relatives) has been
  1310 removed.  Use "{m..<n}" (and relatives) instead.
  1311 
  1312 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1313 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1314 ``declare [[simproc del: neq]]''.
  1315 
  1316 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1317 True/False.
  1318 
  1319 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1320 
  1321 * Theorem setsum_mult renamed to setsum_right_distrib.
  1322 
  1323 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1324 ``rule'' method.
  1325 
  1326 * Reimplemented methods "sat" and "satx", with several improvements:
  1327 goals no longer need to be stated as "<prems> ==> False", equivalences
  1328 (i.e. "=" on type bool) are handled, variable names of the form
  1329 "lit_<n>" are no longer reserved, significant speedup.
  1330 
  1331 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1332 zChaff is still supported as well.
  1333 
  1334 * 'inductive' and 'datatype': provide projections of mutual rules,
  1335 bundled as foo_bar.inducts;
  1336 
  1337 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1338 Library.
  1339 
  1340 * Library: moved theory Accessible_Part to main HOL.
  1341 
  1342 * Library: added theory Coinductive_List of potentially infinite lists
  1343 as greatest fixed-point.
  1344 
  1345 * Library: added theory AssocList which implements (finite) maps as
  1346 association lists.
  1347 
  1348 * Method "evaluation" solves goals (i.e. a boolean expression)
  1349 efficiently by compiling it to ML.  The goal is "proved" (via an
  1350 oracle) if it evaluates to True.
  1351 
  1352 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1353 also when invoked by the simplifier.  This results in the Simplifier
  1354 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1355 Configuration option fast_arith_split_limit=0 recovers the old
  1356 behavior.
  1357 
  1358 * Support for hex (0x20) and binary (0b1001) numerals.
  1359 
  1360 * New method: reify eqs (t), where eqs are equations for an
  1361 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1362 parameter, computes a term s::'b and a list xs::'a list and proves the
  1363 theorem I xs s = t. This is also known as reification or quoting. The
  1364 resulting theorem is applied to the subgoal to substitute t with I xs
  1365 s.  If t is omitted, the subgoal itself is reified.
  1366 
  1367 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1368 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1369 where f is supposed to be a computable function (in the sense of code
  1370 generattion). The method uses reify to compute s and xs as above then
  1371 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1372 r and finally gets the theorem t = r, which is again applied to the
  1373 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1374 
  1375 * Reflection: Automatic reification now handels binding, an example is
  1376 available in src/HOL/ex/ReflectionEx.thy
  1377 
  1378 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1379 command 'statespace' that is similar to 'record', but introduces an
  1380 abstract specification based on the locale infrastructure instead of
  1381 HOL types.  This leads to extra flexibility in composing state spaces,
  1382 in particular multiple inheritance and renaming of components.
  1383 
  1384 
  1385 *** HOL-Complex ***
  1386 
  1387 * Hyperreal: Functions root and sqrt are now defined on negative real
  1388 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1389 Nonnegativity side conditions have been removed from many lemmas, so
  1390 that more subgoals may now be solved by simplification; potential
  1391 INCOMPATIBILITY.
  1392 
  1393 * Real: new type classes formalize real normed vector spaces and
  1394 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1395 and norm :: 'a => real.
  1396 
  1397 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1398 reals into other types. The overloaded constant Reals :: 'a set is now
  1399 defined as range of_real; potential INCOMPATIBILITY.
  1400 
  1401 * Real: proper support for ML code generation, including 'quickcheck'.
  1402 Reals are implemented as arbitrary precision rationals.
  1403 
  1404 * Hyperreal: Several constants that previously worked only for the
  1405 reals have been generalized, so they now work over arbitrary vector
  1406 spaces. Type annotations may need to be added in some cases; potential
  1407 INCOMPATIBILITY.
  1408 
  1409   Infinitesimal  :: ('a::real_normed_vector) star set
  1410   HFinite        :: ('a::real_normed_vector) star set
  1411   HInfinite      :: ('a::real_normed_vector) star set
  1412   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1413   monad          :: ('a::real_normed_vector) star => 'a star set
  1414   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1415   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1416   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1417   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1418   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1419   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1420   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1421   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1422   sgn            :: 'a::real_normed_vector => 'a
  1423   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1424 
  1425 * Complex: Some complex-specific constants are now abbreviations for
  1426 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1427 hnorm.  Other constants have been entirely removed in favor of the
  1428 polymorphic versions (INCOMPATIBILITY):
  1429 
  1430   approx        <-- capprox
  1431   HFinite       <-- CFinite
  1432   HInfinite     <-- CInfinite
  1433   Infinitesimal <-- CInfinitesimal
  1434   monad         <-- cmonad
  1435   galaxy        <-- cgalaxy
  1436   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1437   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1438   (ns)deriv     <-- (ns)cderiv
  1439 
  1440 
  1441 *** HOL-Algebra ***
  1442 
  1443 * Formalisation of ideals and the quotient construction over rings.
  1444 
  1445 * Order and lattice theory no longer based on records.
  1446 INCOMPATIBILITY.
  1447 
  1448 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1449 greatest_closed.  INCOMPATIBILITY.
  1450 
  1451 * Method algebra is now set up via an attribute.  For examples see
  1452 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1453 of algebraic structures.
  1454 
  1455 * Renamed theory CRing to Ring.
  1456 
  1457 
  1458 *** HOL-Nominal ***
  1459 
  1460 * Substantial, yet incomplete support for nominal datatypes (binding
  1461 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  1462 src/HOL/Nominal/Examples.  Prospective users should consult
  1463 http://isabelle.in.tum.de/nominal/
  1464 
  1465 
  1466 *** ML ***
  1467 
  1468 * ML basics: just one true type int, which coincides with IntInf.int
  1469 (even on SML/NJ).
  1470 
  1471 * ML within Isar: antiquotations allow to embed statically-checked
  1472 formal entities in the source, referring to the context available at
  1473 compile-time.  For example:
  1474 
  1475 ML {* @{sort "{zero,one}"} *}
  1476 ML {* @{typ "'a => 'b"} *}
  1477 ML {* @{term "%x. x"} *}
  1478 ML {* @{prop "x == y"} *}
  1479 ML {* @{ctyp "'a => 'b"} *}
  1480 ML {* @{cterm "%x. x"} *}
  1481 ML {* @{cprop "x == y"} *}
  1482 ML {* @{thm asm_rl} *}
  1483 ML {* @{thms asm_rl} *}
  1484 ML {* @{type_name c} *}
  1485 ML {* @{type_syntax c} *}
  1486 ML {* @{const_name c} *}
  1487 ML {* @{const_syntax c} *}
  1488 ML {* @{context} *}
  1489 ML {* @{theory} *}
  1490 ML {* @{theory Pure} *}
  1491 ML {* @{theory_ref} *}
  1492 ML {* @{theory_ref Pure} *}
  1493 ML {* @{simpset} *}
  1494 ML {* @{claset} *}
  1495 ML {* @{clasimpset} *}
  1496 
  1497 The same works for sources being ``used'' within an Isar context.
  1498 
  1499 * ML in Isar: improved error reporting; extra verbosity with
  1500 ML_Context.trace enabled.
  1501 
  1502 * Pure/General/table.ML: the join operations now works via exceptions
  1503 DUP/SAME instead of type option. This is simpler in simple cases, and
  1504 admits slightly more efficient complex applications.
  1505 
  1506 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1507 use Context.generic instead of just theory.
  1508 
  1509 * Pure: datatype Context.generic joins theory/Proof.context and
  1510 provides some facilities for code that works in either kind of
  1511 context, notably GenericDataFun for uniform theory and proof data.
  1512 
  1513 * Pure: simplified internal attribute type, which is now always
  1514 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  1515 local (Proof.context) attributes have been discontinued, while
  1516 minimizing code duplication. Thm.rule_attribute and
  1517 Thm.declaration_attribute build canonical attributes; see also structure
  1518 Context for further operations on Context.generic, notably
  1519 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  1520 declarations and definitions.
  1521 
  1522 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1523 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1524 init only required for impure data. INCOMPATIBILITY: empty really need
  1525 to be empty (no dependencies on theory content!)
  1526 
  1527 * Pure/kernel: consts certification ignores sort constraints given in
  1528 signature declarations. (This information is not relevant to the
  1529 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  1530 potential INCOMPATIBILITY.
  1531 
  1532 * Pure: axiomatic type classes are now purely definitional, with
  1533 explicit proofs of class axioms and super class relations performed
  1534 internally. See Pure/axclass.ML for the main internal interfaces --
  1535 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1536 AxClass.axiomatize_class/classrel/arity supersede
  1537 Sign.add_classes/classrel/arities.
  1538 
  1539 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1540 global/local versions on theory vs. Proof.context have been
  1541 discontinued; Attrib.syntax and Method.syntax have been adapted
  1542 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1543 attributes, methods, etc.
  1544 
  1545 * Pure: several functions of signature "... -> theory -> theory * ..."
  1546 have been reoriented to "... -> theory -> ... * theory" in order to
  1547 allow natural usage in combination with the ||>, ||>>, |-> and
  1548 fold_map combinators.
  1549 
  1550 * Pure: official theorem names (closed derivations) and additional
  1551 comments (tags) are now strictly separate.  Name hints -- which are
  1552 maintained as tags -- may be attached any time without affecting the
  1553 derivation.
  1554 
  1555 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1556 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1557 achieve the old behaviour.
  1558 
  1559 * Pure: the "Goal" constant is now called "prop", supporting a
  1560 slightly more general idea of ``protecting'' meta-level rule
  1561 statements.
  1562 
  1563 * Pure: Logic.(un)varify only works in a global context, which is now
  1564 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1565 Logic.legacy_(un)varify as temporary workaround.
  1566 
  1567 * Pure: structure Name provides scalable operations for generating
  1568 internal variable names, notably Name.variants etc.  This replaces
  1569 some popular functions from term.ML:
  1570 
  1571   Term.variant		->  Name.variant
  1572   Term.variantlist	->  Name.variant_list
  1573   Term.invent_names	->  Name.invent_list
  1574 
  1575 Note that low-level renaming rarely occurs in new code -- operations
  1576 from structure Variable are used instead (see below).
  1577 
  1578 * Pure: structure Variable provides fundamental operations for proper
  1579 treatment of fixed/schematic variables in a context.  For example,
  1580 Variable.import introduces fixes for schematics of given facts and
  1581 Variable.export reverses the effect (up to renaming) -- this replaces
  1582 various freeze_thaw operations.
  1583 
  1584 * Pure: structure Goal provides simple interfaces for
  1585 init/conclude/finish and tactical prove operations (replacing former
  1586 Tactic.prove).  Goal.prove is the canonical way to prove results
  1587 within a given context; Goal.prove_global is a degraded version for
  1588 theory level goals, including a global Drule.standard.  Note that
  1589 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1590 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1591 in a locale context).
  1592 
  1593 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  1594 and type checking (Syntax.check_term etc.), with common combinations
  1595 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  1596 which are considered legacy and await removal.
  1597 
  1598 * Pure/Syntax: generic interfaces for type unchecking
  1599 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  1600 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  1601 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  1602 available for convenience, but refer to the very same operations using
  1603 a mere theory instead of a full context.
  1604 
  1605 * Isar: simplified treatment of user-level errors, using exception
  1606 ERROR of string uniformly.  Function error now merely raises ERROR,
  1607 without any side effect on output channels.  The Isar toplevel takes
  1608 care of proper display of ERROR exceptions.  ML code may use plain
  1609 handle/can/try; cat_error may be used to concatenate errors like this:
  1610 
  1611   ... handle ERROR msg => cat_error msg "..."
  1612 
  1613 Toplevel ML code (run directly or through the Isar toplevel) may be
  1614 embedded into the Isar toplevel with exception display/debug like
  1615 this:
  1616 
  1617   Isar.toplevel (fn () => ...)
  1618 
  1619 INCOMPATIBILITY, removed special transform_error facilities, removed
  1620 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1621 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1622 -- use plain ERROR instead.
  1623 
  1624 * Isar: theory setup now has type (theory -> theory), instead of a
  1625 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1626 
  1627 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  1628 ProofContext.debug/verbose flags.
  1629 
  1630 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1631 theory before entering a proof state.  Transactions now always see a
  1632 quasi-functional intermediate checkpoint, both in interactive and
  1633 batch mode.
  1634 
  1635 * Isar: simplified interfaces for outer syntax.  Renamed
  1636 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  1637 OuterSyntax.add_parsers -- this functionality is now included in
  1638 OuterSyntax.command etc.  INCOMPATIBILITY.
  1639 
  1640 * Simplifier: the simpset of a running simplification process now
  1641 contains a proof context (cf. Simplifier.the_context), which is the
  1642 very context that the initial simpset has been retrieved from (by
  1643 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1644 (solver, looper etc.) may depend on arbitrary proof data.
  1645 
  1646 * Simplifier.inherit_context inherits the proof context (plus the
  1647 local bounds) of the current simplification process; any simproc
  1648 etc. that calls the Simplifier recursively should do this!  Removed
  1649 former Simplifier.inherit_bounds, which is already included here --
  1650 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1651 specify an explicit context using Simplifier.context/theory_context.
  1652 
  1653 * Simplifier/Classical Reasoner: more abstract interfaces
  1654 change_simpset/claset for modifying the simpset/claset reference of a
  1655 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1656 INCOMPATIBILITY.
  1657 
  1658 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1659 "Trueprop" etc.
  1660 
  1661 
  1662 *** System ***
  1663 
  1664 * settings: the default heap location within ISABELLE_HOME_USER now
  1665 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  1666 Isabelle installations.
  1667 
  1668 * isabelle-process: option -S (secure mode) disables some critical
  1669 operations, notably runtime compilation and evaluation of ML source
  1670 code.
  1671 
  1672 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  1673 
  1674 * Support for parallel execution, using native multicore support of
  1675 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  1676 independent theories, according to the given theory header
  1677 specifications. The maximum number of worker threads is specified via
  1678 usedir option -M or the "max-threads" setting in Proof General. A
  1679 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  1680 to 6 on a 8-core machine.  User-code needs to observe certain
  1681 guidelines for thread-safe programming, see appendix A in the Isar
  1682 Implementation manual.
  1683 
  1684 
  1685 
  1686 New in Isabelle2005 (October 2005)
  1687 ----------------------------------
  1688 
  1689 *** General ***
  1690 
  1691 * Theory headers: the new header syntax for Isar theories is
  1692 
  1693   theory <name>
  1694   imports <theory1> ... <theoryN>
  1695   uses <file1> ... <fileM>
  1696   begin
  1697 
  1698 where the 'uses' part is optional.  The previous syntax
  1699 
  1700   theory <name> = <theory1> + ... + <theoryN>:
  1701 
  1702 will disappear in the next release.  Use isatool fixheaders to convert
  1703 existing theory files.  Note that there is no change in ancient
  1704 non-Isar theories now, but these will disappear soon.
  1705 
  1706 * Theory loader: parent theories can now also be referred to via
  1707 relative and absolute paths.
  1708 
  1709 * Command 'find_theorems' searches for a list of criteria instead of a
  1710 list of constants. Known criteria are: intro, elim, dest, name:string,
  1711 simp:term, and any term. Criteria can be preceded by '-' to select
  1712 theorems that do not match. Intro, elim, dest select theorems that
  1713 match the current goal, name:s selects theorems whose fully qualified
  1714 name contain s, and simp:term selects all simplification rules whose
  1715 lhs match term.  Any other term is interpreted as pattern and selects
  1716 all theorems matching the pattern. Available in ProofGeneral under
  1717 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1718 
  1719   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1720 
  1721 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1722 matching the current goal as introduction rule and not having "HOL."
  1723 in their name (i.e. not being defined in theory HOL).
  1724 
  1725 * Command 'thms_containing' has been discontinued in favour of
  1726 'find_theorems'; INCOMPATIBILITY.
  1727 
  1728 * Communication with Proof General is now 8bit clean, which means that
  1729 Unicode text in UTF-8 encoding may be used within theory texts (both
  1730 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1731 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1732 
  1733   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1734   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1735 
  1736 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1737 Classical Reasoner.  Typical big applications run around 2 times
  1738 faster.
  1739 
  1740 
  1741 *** Document preparation ***
  1742 
  1743 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1744 of raw sources.  Only those symbols that do not require additional
  1745 LaTeX packages (depending on comments in isabellesym.sty) are
  1746 displayed properly, everything else is left verbatim.  isatool display
  1747 and isatool print are used as front ends (these are subject to the
  1748 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1749 
  1750 * Command tags control specific markup of certain regions of text,
  1751 notably folding and hiding.  Predefined tags include "theory" (for
  1752 theory begin and end), "proof" for proof commands, and "ML" for
  1753 commands involving ML code; the additional tags "visible" and
  1754 "invisible" are unused by default.  Users may give explicit tag
  1755 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1756 interpretation of tags is determined by the LaTeX job during document
  1757 preparation: see option -V of isatool usedir, or options -n and -t of
  1758 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1759 \isadroptag.
  1760 
  1761 Several document versions may be produced at the same time via isatool
  1762 usedir (the generated index.html will link all of them).  Typical
  1763 specifications include ''-V document=theory,proof,ML'' to present
  1764 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1765 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1766 these parts without any formal replacement text.  The Isabelle site
  1767 default settings produce ''document'' and ''outline'' versions as
  1768 specified above.
  1769 
  1770 * Several new antiquotations:
  1771 
  1772   @{term_type term} prints a term with its type annotated;
  1773 
  1774   @{typeof term} prints the type of a term;
  1775 
  1776   @{const const} is the same as @{term const}, but checks that the
  1777   argument is a known logical constant;
  1778 
  1779   @{term_style style term} and @{thm_style style thm} print a term or
  1780   theorem applying a "style" to it
  1781 
  1782   @{ML text}
  1783 
  1784 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1785 definitions, equations, inequations etc., 'concl' printing only the
  1786 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1787 to print the specified premise.  TermStyle.add_style provides an ML
  1788 interface for introducing further styles.  See also the "LaTeX Sugar"
  1789 document practical applications.  The ML antiquotation prints
  1790 type-checked ML expressions verbatim.
  1791 
  1792 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1793 and 'text' support optional locale specification '(in loc)', which
  1794 specifies the default context for interpreting antiquotations.  For
  1795 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1796 
  1797 * Option 'locale=NAME' of antiquotations specifies an alternative
  1798 context interpreting the subsequent argument.  For example: @{thm
  1799 [locale=lattice] inf_assoc}.
  1800 
  1801 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1802 a proof context.
  1803 
  1804 * Proper output of antiquotations for theory commands involving a
  1805 proof context (such as 'locale' or 'theorem (in loc) ...').
  1806 
  1807 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1808 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1809 
  1810 * isatool usedir: new option -C (default true) controls whether option
  1811 -D should include a copy of the original document directory; -C false
  1812 prevents unwanted effects such as copying of administrative CVS data.
  1813 
  1814 
  1815 *** Pure ***
  1816 
  1817 * Considerably improved version of 'constdefs' command.  Now performs
  1818 automatic type-inference of declared constants; additional support for
  1819 local structure declarations (cf. locales and HOL records), see also
  1820 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1821 sequential dependencies of definitions within a single 'constdefs'
  1822 section; moreover, the declared name needs to be an identifier.  If
  1823 all fails, consider to fall back on 'consts' and 'defs' separately.
  1824 
  1825 * Improved indexed syntax and implicit structures.  First of all,
  1826 indexed syntax provides a notational device for subscripted
  1827 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1828 expressions.  Secondly, in a local context with structure
  1829 declarations, number indexes \<^sub>n or the empty index (default
  1830 number 1) refer to a certain fixed variable implicitly; option
  1831 show_structs controls printing of implicit structures.  Typical
  1832 applications of these concepts involve record types and locales.
  1833 
  1834 * New command 'no_syntax' removes grammar declarations (and
  1835 translations) resulting from the given syntax specification, which is
  1836 interpreted in the same manner as for the 'syntax' command.
  1837 
  1838 * 'Advanced' translation functions (parse_translation etc.) may depend
  1839 on the signature of the theory context being presently used for
  1840 parsing/printing, see also isar-ref manual.
  1841 
  1842 * Improved 'oracle' command provides a type-safe interface to turn an
  1843 ML expression of type theory -> T -> term into a primitive rule of
  1844 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1845 is already included here); see also FOL/ex/IffExample.thy;
  1846 INCOMPATIBILITY.
  1847 
  1848 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1849 before); "cI" is no longer bound, use "c.intro" instead.
  1850 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1851 axclasses vs. locales.
  1852 
  1853 * Improved internal renaming of symbolic identifiers -- attach primes
  1854 instead of base 26 numbers.
  1855 
  1856 * New flag show_question_marks controls printing of leading question
  1857 marks in schematic variable names.
  1858 
  1859 * In schematic variable names, *any* symbol following \<^isub> or
  1860 \<^isup> is now treated as part of the base name.  For example, the
  1861 following works without printing of awkward ".0" indexes:
  1862 
  1863   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1864     by simp
  1865 
  1866 * Inner syntax includes (*(*nested*) comments*).
  1867 
  1868 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1869 annotations as "(00...)".
  1870 
  1871 * Clear separation of logical types and nonterminals, where the latter
  1872 may only occur in 'syntax' specifications or type abbreviations.
  1873 Before that distinction was only partially implemented via type class
  1874 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1875 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1876 exotic syntax specifications may require further adaption
  1877 (e.g. Cube/Cube.thy).
  1878 
  1879 * Removed obsolete type class "logic", use the top sort {} instead.
  1880 Note that non-logical types should be declared as 'nonterminals'
  1881 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1882 specifications.
  1883 
  1884 * Attributes 'induct' and 'cases': type or set names may now be
  1885 locally fixed variables as well.
  1886 
  1887 * Simplifier: can now control the depth to which conditional rewriting
  1888 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1889 Limit.
  1890 
  1891 * Simplifier: simplification procedures may now take the current
  1892 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1893 interface), which is very useful for calling the Simplifier
  1894 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1895 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1896 low-level mk_simproc no longer applies Logic.varify internally, to
  1897 allow for use in a context of fixed variables.
  1898 
  1899 * thin_tac now works even if the assumption being deleted contains !!
  1900 or ==>.  More generally, erule now works even if the major premise of
  1901 the elimination rule contains !! or ==>.
  1902 
  1903 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1904 
  1905 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1906 from Pure, which contains all common declarations already.  Both
  1907 theories are defined via plain Isabelle/Isar .thy files.
  1908 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1909 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1910 use isatool fixcpure to adapt your theory and ML sources.
  1911 
  1912 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1913 selections of theorems in named facts via index ranges.
  1914 
  1915 * 'print_theorems': in theory mode, really print the difference
  1916 wrt. the last state (works for interactive theory development only),
  1917 in proof mode print all local facts (cf. 'print_facts');
  1918 
  1919 * 'hide': option '(open)' hides only base names.
  1920 
  1921 * More efficient treatment of intermediate checkpoints in interactive
  1922 theory development.
  1923 
  1924 * Code generator is now invoked via code_module (incremental code
  1925 generation) and code_library (modular code generation, ML structures
  1926 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1927 must be quoted when used as identifiers.
  1928 
  1929 * New 'value' command for reading, evaluating and printing terms using
  1930 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1931 quoted when used as identifier.
  1932 
  1933 
  1934 *** Locales ***
  1935 
  1936 * New commands for the interpretation of locale expressions in
  1937 theories (1), locales (2) and proof contexts (3).  These generate
  1938 proof obligations from the expression specification.  After the
  1939 obligations have been discharged, theorems of the expression are added
  1940 to the theory, target locale or proof context.  The synopsis of the
  1941 commands is a follows:
  1942 
  1943   (1) interpretation expr inst
  1944   (2) interpretation target < expr
  1945   (3) interpret expr inst
  1946 
  1947 Interpretation in theories and proof contexts require a parameter
  1948 instantiation of terms from the current context.  This is applied to
  1949 specifications and theorems of the interpreted expression.
  1950 Interpretation in locales only permits parameter renaming through the
  1951 locale expression.  Interpretation is smart in that interpretations
  1952 that are active already do not occur in proof obligations, neither are
  1953 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1954 inspect active interpretations of a particular locale.  For details,
  1955 see the Isar Reference manual.  Examples can be found in
  1956 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1957 
  1958 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1959 'interpret' instead.
  1960 
  1961 * New context element 'constrains' for adding type constraints to
  1962 parameters.
  1963 
  1964 * Context expressions: renaming of parameters with syntax
  1965 redeclaration.
  1966 
  1967 * Locale declaration: 'includes' disallowed.
  1968 
  1969 * Proper static binding of attribute syntax -- i.e. types / terms /
  1970 facts mentioned as arguments are always those of the locale definition
  1971 context, independently of the context of later invocations.  Moreover,
  1972 locale operations (renaming and type / term instantiation) are applied
  1973 to attribute arguments as expected.
  1974 
  1975 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1976 actual attributes; rare situations may require Attrib.attribute to
  1977 embed those attributes into Attrib.src that lack concrete syntax.
  1978 Attribute implementations need to cooperate properly with the static
  1979 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1980 Attrib.XXX_thm etc. already do the right thing without further
  1981 intervention.  Only unusual applications -- such as "where" or "of"
  1982 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1983 on the context and the facts involved -- may have to assign parsed
  1984 values to argument tokens explicitly.
  1985 
  1986 * Changed parameter management in theorem generation for long goal
  1987 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1988 theorem statement in rare situations.
  1989 
  1990 * Locale inspection command 'print_locale' omits notes elements.  Use
  1991 'print_locale!' to have them included in the output.
  1992 
  1993 
  1994 *** Provers ***
  1995 
  1996 * Provers/hypsubst.ML: improved version of the subst method, for
  1997 single-step rewriting: it now works in bound variable contexts. New is
  1998 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1999 rewrite a different subterm than the original subst method, which is
  2000 still available as 'simplesubst'.
  2001 
  2002 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2003 and quasi orders.
  2004 
  2005 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2006 reflexive-transitive closure of relations.
  2007 
  2008 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2009 limit (previously hard-coded with a value of 20) user-definable.
  2010 
  2011 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2012 is peformed already.  Object-logics merely need to finish their
  2013 initial simpset configuration as before.  INCOMPATIBILITY.
  2014 
  2015 
  2016 *** HOL ***
  2017 
  2018 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2019 
  2020   syntax (epsilon)
  2021     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2022 
  2023 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2024 and x-symbol; use option '-m epsilon' to get it actually printed.
  2025 Moreover, the mathematically important symbolic identifier \<epsilon>
  2026 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2027 
  2028 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2029 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2030 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2031 support corresponding Isar calculations.
  2032 
  2033 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2034 instead of ":".
  2035 
  2036 * theory SetInterval: changed the syntax for open intervals:
  2037 
  2038   Old       New
  2039   {..n(}    {..<n}
  2040   {)n..}    {n<..}
  2041   {m..n(}   {m..<n}
  2042   {)m..n}   {m<..n}
  2043   {)m..n(}  {m<..<n}
  2044 
  2045 The old syntax is still supported but will disappear in the next
  2046 release.  For conversion use the following Emacs search and replace
  2047 patterns (these are not perfect but work quite well):
  2048 
  2049   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2050   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2051 
  2052 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2053 equalities in commutative rings; method 'algebra' provides a generic
  2054 interface.
  2055 
  2056 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2057 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2058 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2059 be a tuple pattern.
  2060 
  2061 Some new syntax forms are available:
  2062 
  2063   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2064   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2065   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2066   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2067 
  2068 The latter form "\<Sum>x < k. e" used to be based on a separate
  2069 function "Summation", which has been discontinued.
  2070 
  2071 * theory Finite_Set: in structured induction proofs, the insert case
  2072 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2073 (insert F x)'.
  2074 
  2075 * The 'refute' command has been extended to support a much larger
  2076 fragment of HOL, including axiomatic type classes, constdefs and
  2077 typedefs, inductive datatypes and recursion.
  2078 
  2079 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2080 Requires zChaff with proof generation to be installed.  See
  2081 HOL/ex/SAT_Examples.thy for examples.
  2082 
  2083 * Datatype induction via method 'induct' now preserves the name of the
  2084 induction variable. For example, when proving P(xs::'a list) by
  2085 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2086 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2087 in unstructured proof scripts.
  2088 
  2089 * Reworked implementation of records.  Improved scalability for
  2090 records with many fields, avoiding performance problems for type
  2091 inference. Records are no longer composed of nested field types, but
  2092 of nested extension types. Therefore the record type only grows linear
  2093 in the number of extensions and not in the number of fields.  The
  2094 top-level (users) view on records is preserved.  Potential
  2095 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2096 old record representation. The type generated for a record is called
  2097 <record_name>_ext_type.
  2098 
  2099 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2100 proofs triggered by a record definition or a simproc (if
  2101 quick_and_dirty is enabled).  Definitions of large records can take
  2102 quite long.
  2103 
  2104 New simproc record_upd_simproc for simplification of multiple record
  2105 updates enabled by default.  Moreover, trivial updates are also
  2106 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2107 occasionally, since simplification is more powerful by default.
  2108 
  2109 * typedef: proper support for polymorphic sets, which contain extra
  2110 type-variables in the term.
  2111 
  2112 * Simplifier: automatically reasons about transitivity chains
  2113 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2114 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2115 old proofs break occasionally as simplification may now solve more
  2116 goals than previously.
  2117 
  2118 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2119 present.  Works for all partial orders (class "order"), in particular
  2120 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2121 just like y <= x.
  2122 
  2123 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2124 bound variable or a constant then the let is unfolded.  Otherwise
  2125 first a is simplified to b, and then f b is simplified to g. If
  2126 possible we abstract b from g arriving at "let x = b in h x",
  2127 otherwise we unfold the let and arrive at g.  The simproc can be
  2128 enabled/disabled by the reference use_let_simproc.  Potential
  2129 INCOMPATIBILITY since simplification is more powerful by default.
  2130 
  2131 * Classical reasoning: the meson method now accepts theorems as arguments.
  2132 
  2133 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2134 jobs to provide advice on the provability of subgoals.
  2135 
  2136 * Theory OrderedGroup and Ring_and_Field: various additions and
  2137 improvements to faciliate calculations involving equalities and
  2138 inequalities.
  2139 
  2140 The following theorems have been eliminated or modified
  2141 (INCOMPATIBILITY):
  2142 
  2143   abs_eq             now named abs_of_nonneg
  2144   abs_of_ge_0        now named abs_of_nonneg
  2145   abs_minus_eq       now named abs_of_nonpos
  2146   imp_abs_id         now named abs_of_nonneg
  2147   imp_abs_neg_id     now named abs_of_nonpos
  2148   mult_pos           now named mult_pos_pos
  2149   mult_pos_le        now named mult_nonneg_nonneg
  2150   mult_pos_neg_le    now named mult_nonneg_nonpos
  2151   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2152   mult_neg           now named mult_neg_neg
  2153   mult_neg_le        now named mult_nonpos_nonpos
  2154 
  2155 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2156      
  2157      zero_le_square
  2158      not_square_less_zero 
  2159 
  2160   The following lemmas have been deleted from Real/RealPow:
  2161   
  2162      realpow_zero_zero
  2163      realpow_two
  2164      realpow_less
  2165      zero_le_power
  2166      realpow_two_le
  2167      abs_realpow_two
  2168      realpow_two_abs     
  2169 
  2170 * Theory Parity: added rules for simplifying exponents.
  2171 
  2172 * Theory List:
  2173 
  2174 The following theorems have been eliminated or modified
  2175 (INCOMPATIBILITY):
  2176 
  2177   list_all_Nil       now named list_all.simps(1)
  2178   list_all_Cons      now named list_all.simps(2)
  2179   list_all_conv      now named list_all_iff
  2180   set_mem_eq         now named mem_iff
  2181 
  2182 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2183 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2184 
  2185 
  2186 *** HOL-Complex ***
  2187 
  2188 * Theory RealDef: better support for embedding natural numbers and
  2189 integers in the reals.
  2190 
  2191 The following theorems have been eliminated or modified
  2192 (INCOMPATIBILITY):
  2193 
  2194   exp_ge_add_one_self  now requires no hypotheses
  2195   real_of_int_add      reversed direction of equality (use [symmetric])
  2196   real_of_int_minus    reversed direction of equality (use [symmetric])
  2197   real_of_int_diff     reversed direction of equality (use [symmetric])
  2198   real_of_int_mult     reversed direction of equality (use [symmetric])
  2199 
  2200 * Theory RComplete: expanded support for floor and ceiling functions.
  2201 
  2202 * Theory Ln is new, with properties of the natural logarithm
  2203 
  2204 * Hyperreal: There is a new type constructor "star" for making
  2205 nonstandard types.  The old type names are now type synonyms:
  2206 
  2207   hypreal = real star
  2208   hypnat = nat star
  2209   hcomplex = complex star
  2210 
  2211 * Hyperreal: Many groups of similarly-defined constants have been
  2212 replaced by polymorphic versions (INCOMPATIBILITY):
  2213 
  2214   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2215 
  2216   starset      <-- starsetNat, starsetC
  2217   *s*          <-- *sNat*, *sc*
  2218   starset_n    <-- starsetNat_n, starsetC_n
  2219   *sn*         <-- *sNatn*, *scn*
  2220   InternalSets <-- InternalNatSets, InternalCSets
  2221 
  2222   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2223   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2224   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2225   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2226   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2227 
  2228 * Hyperreal: Many type-specific theorems have been removed in favor of
  2229 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2230 
  2231   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2232   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2233   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2234   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2235   right_minus <-- hypreal_add_minus
  2236   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2237   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2238   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2239   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2240   mult_1_right <-- hcomplex_mult_one_right
  2241   mult_zero_left <-- hcomplex_mult_zero_left
  2242   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2243   right_distrib <-- hypnat_add_mult_distrib2
  2244   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2245   right_inverse <-- hypreal_mult_inverse
  2246   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2247   order_refl <-- {hypreal,hypnat}_le_refl
  2248   order_trans <-- {hypreal,hypnat}_le_trans
  2249   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2250   order_less_le <-- {hypreal,hypnat}_less_le
  2251   linorder_linear <-- {hypreal,hypnat}_le_linear
  2252   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2253   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2254   add_nonneg_nonneg <-- hypreal_le_add_order
  2255 
  2256 * Hyperreal: Separate theorems having to do with type-specific
  2257 versions of constants have been merged into theorems that apply to the
  2258 new polymorphic constants (INCOMPATIBILITY):
  2259 
  2260   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2261   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2262   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2263   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2264   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2265   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2266   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2267   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2268   STAR_diff <-- {STAR,STARC}_diff
  2269   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2270     STARC_hcomplex_of_complex}_image_subset
  2271   starset_n_Un <-- starset{Nat,C}_n_Un
  2272   starset_n_Int <-- starset{Nat,C}_n_Int
  2273   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2274   starset_n_diff <-- starset{Nat,C}_n_diff
  2275   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2276   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2277   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2278   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2279   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2280   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2281   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2282   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2283   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2284   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2285   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2286   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2287   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2288   starfun_diff <-- starfun{C,RC,CR}_diff
  2289   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2290   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2291   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2292   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2293   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2294   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2295   starfun_Id <-- starfunC_Id
  2296   starfun_approx <-- starfun{Nat,CR}_approx
  2297   starfun_capprox <-- starfun{C,RC}_capprox
  2298   starfun_abs <-- starfunNat_rabs
  2299   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2300   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2301   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2302   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2303   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2304   starfun_add_approx <-- starfunCR_add_approx
  2305   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2306   starfun_divide <-- starfun{C,CR,RC}_divide
  2307   starfun_n <-- starfun{Nat,C}_n
  2308   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2309   starfun_n_add <-- starfun{Nat,C}_n_add
  2310   starfun_n_add_minus <-- starfunNat_n_add_minus
  2311   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2312   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2313   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2314 
  2315   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2316   star_n_minus <-- {hypreal,hcomplex}_minus
  2317   star_n_diff <-- {hypreal,hcomplex}_diff
  2318   star_n_mult <-- {hypreal,hcomplex}_mult
  2319   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2320   star_n_le <-- {hypreal,hypnat}_le
  2321   star_n_less <-- {hypreal,hypnat}_less
  2322   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2323   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2324   star_n_abs <-- hypreal_hrabs
  2325   star_n_divide <-- hcomplex_divide
  2326 
  2327   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2328   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2329   star_of_diff <-- hypreal_of_real_diff
  2330   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2331   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2332   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2333   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2334   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2335   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2336   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2337   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2338   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2339   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2340   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2341   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2342   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2343   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2344   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2345   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2346   star_of_power <-- hypreal_of_real_power
  2347   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2348 
  2349 * Hyperreal: new method "transfer" that implements the transfer
  2350 principle of nonstandard analysis. With a subgoal that mentions
  2351 nonstandard types like "'a star", the command "apply transfer"
  2352 replaces it with an equivalent one that mentions only standard types.
  2353 To be successful, all free variables must have standard types; non-
  2354 standard variables must have explicit universal quantifiers.
  2355 
  2356 * Hyperreal: A theory of Taylor series.
  2357 
  2358 
  2359 *** HOLCF ***
  2360 
  2361 * Discontinued special version of 'constdefs' (which used to support
  2362 continuous functions) in favor of the general Pure one with full
  2363 type-inference.
  2364 
  2365 * New simplification procedure for solving continuity conditions; it
  2366 is much faster on terms with many nested lambda abstractions (cubic
  2367 instead of exponential time).
  2368 
  2369 * New syntax for domain package: selector names are now optional.
  2370 Parentheses should be omitted unless argument is lazy, for example:
  2371 
  2372   domain 'a stream = cons "'a" (lazy "'a stream")
  2373 
  2374 * New command 'fixrec' for defining recursive functions with pattern
  2375 matching; defining multiple functions with mutual recursion is also
  2376 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2377 sinr, or any data constructor defined by the domain package. The given
  2378 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2379 syntax and examples.
  2380 
  2381 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2382 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2383 but the proof obligation additionally includes an admissibility
  2384 requirement. The packages generate instances of class cpo or pcpo,
  2385 with continuity and strictness theorems for Rep and Abs.
  2386 
  2387 * HOLCF: Many theorems have been renamed according to a more standard naming
  2388 scheme (INCOMPATIBILITY):
  2389 
  2390   foo_inject:  "foo$x = foo$y ==> x = y"
  2391   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2392   foo_less:    "(foo$x << foo$y) = (x << y)"
  2393   foo_strict:  "foo$UU = UU"
  2394   foo_defined: "... ==> foo$x ~= UU"
  2395   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2396 
  2397 
  2398 *** ZF ***
  2399 
  2400 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2401 including the First Isomorphism Theorem (on quotienting by the kernel
  2402 of a homomorphism).
  2403 
  2404 * ZF/Simplifier: install second copy of type solver that actually
  2405 makes use of TC rules declared to Isar proof contexts (or locales);
  2406 the old version is still required for ML proof scripts.
  2407 
  2408 
  2409 *** Cube ***
  2410 
  2411 * Converted to Isar theory format; use locales instead of axiomatic
  2412 theories.
  2413 
  2414 
  2415 *** ML ***
  2416 
  2417 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2418 for ||>, ||>>, |>>,
  2419 
  2420 * Pure/library.ML no longer defines its own option datatype, but uses
  2421 that of the SML basis, which has constructors NONE and SOME instead of
  2422 None and Some, as well as exception Option.Option instead of OPTION.
  2423 The functions the, if_none, is_some, is_none have been adapted
  2424 accordingly, while Option.map replaces apsome.
  2425 
  2426 * Pure/library.ML: the exception LIST has been given up in favour of
  2427 the standard exceptions Empty and Subscript, as well as
  2428 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2429 superceded by the standard hd and tl functions etc.
  2430 
  2431 A number of basic list functions are no longer exported to the ML
  2432 toplevel, as they are variants of predefined functions.  The following
  2433 suggests how one can translate existing code:
  2434 
  2435     rev_append xs ys = List.revAppend (xs, ys)
  2436     nth_elem (i, xs) = List.nth (xs, i)
  2437     last_elem xs = List.last xs
  2438     flat xss = List.concat xss
  2439     seq fs = List.app fs
  2440     partition P xs = List.partition P xs
  2441     mapfilter f xs = List.mapPartial f xs
  2442 
  2443 * Pure/library.ML: several combinators for linear functional
  2444 transformations, notably reverse application and composition:
  2445 
  2446   x |> f                f #> g
  2447   (x, y) |-> f          f #-> g
  2448 
  2449 * Pure/library.ML: introduced/changed precedence of infix operators:
  2450 
  2451   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2452   infix 2 ?;
  2453   infix 3 o oo ooo oooo;
  2454   infix 4 ~~ upto downto;
  2455 
  2456 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2457 infix operators.
  2458 
  2459 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2460 fold_map support linear functional transformations and nesting.  For
  2461 example:
  2462 
  2463   fold f [x1, ..., xN] y =
  2464     y |> f x1 |> ... |> f xN
  2465 
  2466   (fold o fold) f [xs1, ..., xsN] y =
  2467     y |> fold f xs1 |> ... |> fold f xsN
  2468 
  2469   fold f [x1, ..., xN] =
  2470     f x1 #> ... #> f xN
  2471 
  2472   (fold o fold) f [xs1, ..., xsN] =
  2473     fold f xs1 #> ... #> fold f xsN
  2474 
  2475 * Pure/library.ML: the following selectors on type 'a option are
  2476 available:
  2477 
  2478   the:               'a option -> 'a  (*partial*)
  2479   these:             'a option -> 'a  where 'a = 'b list
  2480   the_default: 'a -> 'a option -> 'a
  2481   the_list:          'a option -> 'a list
  2482 
  2483 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2484 basic operations for association lists, following natural argument
  2485 order; moreover the explicit equality predicate passed here avoids
  2486 potentially expensive polymorphic runtime equality checks.
  2487 The old functions may be expressed as follows:
  2488 
  2489   assoc = uncurry (AList.lookup (op =))
  2490   assocs = these oo AList.lookup (op =)
  2491   overwrite = uncurry (AList.update (op =)) o swap
  2492 
  2493 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2494 
  2495   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2496   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2497 
  2498 replacing make_keylist and keyfilter (occassionally used)
  2499 Naive rewrites:
  2500 
  2501   make_keylist = AList.make
  2502   keyfilter = AList.find (op =)
  2503 
  2504 * eq_fst and eq_snd now take explicit equality parameter, thus
  2505   avoiding eqtypes. Naive rewrites:
  2506 
  2507     eq_fst = eq_fst (op =)
  2508     eq_snd = eq_snd (op =)
  2509 
  2510 * Removed deprecated apl and apr (rarely used).
  2511   Naive rewrites:
  2512 
  2513     apl (n, op) =>>= curry op n
  2514     apr (op, m) =>>= fn n => op (n, m)
  2515 
  2516 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2517 provides a reasonably efficient light-weight implementation of sets as
  2518 lists.
  2519 
  2520 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2521 few new operations; existing lookup and update are now curried to
  2522 follow natural argument order (for use with fold etc.);
  2523 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2524 
  2525 * Pure/General: output via the Isabelle channels of
  2526 writeln/warning/error etc. is now passed through Output.output, with a
  2527 hook for arbitrary transformations depending on the print_mode
  2528 (cf. Output.add_mode -- the first active mode that provides a output
  2529 function wins).  Already formatted output may be embedded into further
  2530 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2531 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2532 accommodate easy composition of diagnostic messages etc.  Programmers
  2533 rarely need to care about Output.output or Output.raw at all, with
  2534 some notable exceptions: Output.output is required when bypassing the
  2535 standard channels (writeln etc.), or in token translations to produce
  2536 properly formatted results; Output.raw is required when capturing
  2537 already output material that will eventually be presented to the user
  2538 a second time.  For the default print mode, both Output.output and
  2539 Output.raw have no effect.
  2540 
  2541 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2542 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2543 cumulative results are displayed at the end of a batch session.
  2544 
  2545 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2546 replaced by File.platform_path and File.shell_path (with appropriate
  2547 hooks).  This provides a clean interface for unusual systems where the
  2548 internal and external process view of file names are different.
  2549 
  2550 * Pure: more efficient orders for basic syntactic entities: added
  2551 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2552 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2553 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2554 orders now -- potential INCOMPATIBILITY for code that depends on a
  2555 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2556 Library.sort_strings on result).
  2557 
  2558 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2559 fold_types traverse types/terms from left to right, observing natural
  2560 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2561 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2562 
  2563 * Pure: name spaces have been refined, with significant changes of the
  2564 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2565 to extern(_table).  The plain name entry path is superceded by a
  2566 general 'naming' context, which also includes the 'policy' to produce
  2567 a fully qualified name and external accesses of a fully qualified
  2568 name; NameSpace.extend is superceded by context dependent
  2569 Sign.declare_name.  Several theory and proof context operations modify
  2570 the naming context.  Especially note Theory.restore_naming and
  2571 ProofContext.restore_naming to get back to a sane state; note that
  2572 Theory.add_path is no longer sufficient to recover from
  2573 Theory.absolute_path in particular.
  2574 
  2575 * Pure: new flags short_names (default false) and unique_names
  2576 (default true) for controlling output of qualified names.  If
  2577 short_names is set, names are printed unqualified.  If unique_names is
  2578 reset, the name prefix is reduced to the minimum required to achieve
  2579 the original result when interning again, even if there is an overlap
  2580 with earlier declarations.
  2581 
  2582 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2583 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2584 (useful for printing error messages).  INCOMPATIBILITY.
  2585 
  2586 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2587 Theory.theory are now identified, referring to the universal
  2588 Context.theory (see Pure/context.ML).  Actual signature and theory
  2589 content is managed as theory data.  The old code and interfaces were
  2590 spread over many files and structures; the new arrangement introduces
  2591 considerable INCOMPATIBILITY to gain more clarity:
  2592 
  2593   Context -- theory management operations (name, identity, inclusion,
  2594     parents, ancestors, merge, etc.), plus generic theory data;
  2595 
  2596   Sign -- logical signature and syntax operations (declaring consts,
  2597     types, etc.), plus certify/read for common entities;
  2598 
  2599   Theory -- logical theory operations (stating axioms, definitions,
  2600     oracles), plus a copy of logical signature operations (consts,
  2601     types, etc.); also a few basic management operations (Theory.copy,
  2602     Theory.merge, etc.)
  2603 
  2604 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2605 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2606 for convenience -- they merely return the theory.
  2607 
  2608 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2609 
  2610 * Pure: the Isar proof context type is already defined early in Pure
  2611 as Context.proof (note that ProofContext.context and Proof.context are
  2612 aliases, where the latter is the preferred name).  This enables other
  2613 Isabelle components to refer to that type even before Isar is present.
  2614 
  2615 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2616 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2617 any of these kinds.  For example, Sign.intern typeK is now
  2618 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2619 Theory.hide_types.  Also note that former
  2620 Theory.hide_classes/types/consts are now
  2621 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2622 internalize their arguments!  INCOMPATIBILITY.
  2623 
  2624 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2625 datatype thmref (with constructors Name and NameSelection) instead of
  2626 plain string -- INCOMPATIBILITY;
  2627 
  2628 * Pure: cases produced by proof methods specify options, where NONE
  2629 means to remove case bindings -- INCOMPATIBILITY in
  2630 (RAW_)METHOD_CASES.
  2631 
  2632 * Pure: the following operations retrieve axioms or theorems from a
  2633 theory node or theory hierarchy, respectively:
  2634 
  2635   Theory.axioms_of: theory -> (string * term) list
  2636   Theory.all_axioms_of: theory -> (string * term) list
  2637   PureThy.thms_of: theory -> (string * thm) list
  2638   PureThy.all_thms_of: theory -> (string * thm) list
  2639 
  2640 * Pure: print_tac now outputs the goal through the trace channel.
  2641 
  2642 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2643 Reference Toplevel.debug (default false) controls detailed printing
  2644 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2645 controls execution profiling -- set to 1 for time and 2 for space
  2646 (both increase the runtime).
  2647 
  2648 * Isar session: The initial use of ROOT.ML is now always timed,
  2649 i.e. the log will show the actual process times, in contrast to the
  2650 elapsed wall-clock time that the outer shell wrapper produces.
  2651 
  2652 * Simplifier: improved handling of bound variables (nameless
  2653 representation, avoid allocating new strings).  Simprocs that invoke
  2654 the Simplifier recursively should use Simplifier.inherit_bounds to
  2655 avoid local name clashes.  Failure to do so produces warnings
  2656 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2657 for further details.
  2658 
  2659 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2660 bindings for all theorems stored within a given theory; this may help
  2661 in porting non-Isar theories to Isar ones, while keeping ML proof
  2662 scripts for the time being.
  2663 
  2664 * ML operator HTML.with_charset specifies the charset begin used for
  2665 generated HTML files.  For example:
  2666 
  2667   HTML.with_charset "utf-8" use_thy "Hebrew";
  2668   HTML.with_charset "utf-8" use_thy "Chinese";
  2669 
  2670 
  2671 *** System ***
  2672 
  2673 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2674 isabelle, isatool etc.).
  2675 
  2676 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2677 isatool doc, isatool mkdir, display_drafts etc.).
  2678 
  2679 * isatool usedir: option -f allows specification of the ML file to be
  2680 used by Isabelle; default is ROOT.ML.
  2681 
  2682 * New isatool version outputs the version identifier of the Isabelle
  2683 distribution being used.
  2684 
  2685 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2686 (containing Boolean satisfiability problems) into Isabelle/HOL
  2687 theories.
  2688 
  2689 
  2690 
  2691 New in Isabelle2004 (April 2004)
  2692 --------------------------------
  2693 
  2694 *** General ***
  2695 
  2696 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2697   Replaces linorder.ML.
  2698 
  2699 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2700   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2701   (\<a>...\<z>), are now considered normal letters, and can therefore
  2702   be used anywhere where an ASCII letter (a...zA...Z) has until
  2703   now. COMPATIBILITY: This obviously changes the parsing of some
  2704   terms, especially where a symbol has been used as a binder, say
  2705   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2706   as an identifier.  Fix it by inserting a space around former
  2707   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2708   existing theory and ML files.
  2709 
  2710 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2711 
  2712 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2713   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2714   a normal (but invisible) letter. For multiple letter subscripts repeat
  2715   \<^isub> like this: x\<^isub>1\<^isub>2.
  2716 
  2717 * Pure: There are now sub-/superscripts that can span more than one
  2718   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2719   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2720   superscript. The new control characters are not identifier parts.
  2721 
  2722 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2723   content of "..." to the latex file instead of \isacntrl... . The "..."
  2724   may consist of any printable characters excluding the end bracket >.
  2725 
  2726 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2727   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2728   declare constants "final", which prevents their being given a definition
  2729   later.  It is useful for constants whose behaviour is fixed axiomatically
  2730   rather than definitionally, such as the meta-logic connectives.
  2731 
  2732 * Pure: 'instance' now handles general arities with general sorts
  2733   (i.e. intersections of classes),
  2734 
  2735 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2736   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2737   It can be changed to alter the colors/layout of generated pages.
  2738 
  2739 
  2740 *** Isar ***
  2741 
  2742 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2743   cut_tac, subgoal_tac and thin_tac:
  2744   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2745     locales are no longer forced to write Isar proof scripts.
  2746     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2747     emulations.
  2748   - INCOMPATIBILITY: names of variables to be instantiated may no
  2749     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2750     This is consistent with the instantiation attribute "where".
  2751 
  2752 * Attributes "where" and "of":
  2753   - Now take type variables of instantiated theorem into account when reading
  2754     the instantiation string.  This fixes a bug that caused instantiated
  2755     theorems to have too special types in some circumstances.
  2756   - "where" permits explicit instantiations of type variables.
  2757 
  2758 * Calculation commands "moreover" and "also" no longer interfere with
  2759   current facts ("this"), admitting arbitrary combinations with "then"
  2760   and derived forms.
  2761 
  2762 * Locales:
  2763   - Goal statements involving the context element "includes" no longer
  2764     generate theorems with internal delta predicates (those ending on
  2765     "_axioms") in the premise.
  2766     Resolve particular premise with <locale>.intro to obtain old form.
  2767   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2768     specification and "includes" elements in goal statement.
  2769   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2770     [intro?] and [elim?] (respectively) by default.
  2771   - Experimental command for instantiation of locales in proof contexts:
  2772         instantiate <label>[<attrs>]: <loc>
  2773     Instantiates locale <loc> and adds all its theorems to the current context
  2774     taking into account their attributes.  Label and attrs are optional
  2775     modifiers, like in theorem declarations.  If present, names of
  2776     instantiated theorems are qualified with <label>, and the attributes
  2777     <attrs> are applied after any attributes these theorems might have already.
  2778       If the locale has assumptions, a chained fact of the form
  2779     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2780     are derived.  The command does not support old-style locales declared
  2781     with "locale (open)".
  2782       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2783 
  2784 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2785   (Isar) contexts.
  2786 
  2787 
  2788 *** HOL ***
  2789 
  2790 * Proof import: new image HOL4 contains the imported library from
  2791   the HOL4 system with about 2500 theorems. It is imported by
  2792   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2793   can be used like any other Isabelle image.  See
  2794   HOL/Import/HOL/README for more information.
  2795 
  2796 * Simplifier:
  2797   - Much improved handling of linear and partial orders.
  2798     Reasoners for linear and partial orders are set up for type classes
  2799     "linorder" and "order" respectively, and are added to the default simpset
  2800     as solvers.  This means that the simplifier can build transitivity chains
  2801     to solve goals from the assumptions.
  2802   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2803     of blast or auto after simplification become unnecessary because the goal
  2804     is solved by simplification already.
  2805 
  2806 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2807     all proved in axiomatic type classes for semirings, rings and fields.
  2808 
  2809 * Numerics:
  2810   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2811     now formalized using the Ring_and_Field theory mentioned above.
  2812   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2813     than before, because now they are set up once in a generic manner.
  2814   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2815     Look for the general versions in Ring_and_Field (and Power if they concern
  2816     exponentiation).
  2817 
  2818 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2819 
  2820 * Records:
  2821   - Record types are now by default printed with their type abbreviation
  2822     instead of the list of all field types. This can be configured via
  2823     the reference "print_record_type_abbr".
  2824   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2825     (not enabled by default).
  2826   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2827     EX x. x = sel r to True (not enabled by default).
  2828   - Tactic "record_split_simp_tac" to split and simplify records added.
  2829 
  2830 * 'specification' command added, allowing for definition by
  2831   specification.  There is also an 'ax_specification' command that
  2832   introduces the new constants axiomatically.
  2833 
  2834 * arith(_tac) is now able to generate counterexamples for reals as well.
  2835 
  2836 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2837 
  2838 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2839   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2840 
  2841 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2842   matrix theory to linear programming.
  2843 
  2844 * Unions and Intersections:
  2845   The latex output syntax of UN and INT has been changed
  2846   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2847   i.e. the index formulae has become a subscript.
  2848   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2849 
  2850 * Unions and Intersections over Intervals:
  2851   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2852   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2853   like in normal math, and corresponding versions for < and for intersection.
  2854 
  2855 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2856   lexicographic dictonary ordering has been added as "lexord".
  2857 
  2858 * ML: the legacy theory structures Int and List have been removed. They had
  2859   conflicted with ML Basis Library structures having the same names.
  2860 
  2861 * 'refute' command added to search for (finite) countermodels.  Only works
  2862   for a fragment of HOL.  The installation of an external SAT solver is
  2863   highly recommended.  See "HOL/Refute.thy" for details.
  2864 
  2865 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2866   formulae under an assignment of free variables to random values.
  2867   In contrast to 'refute', it can deal with inductive datatypes,
  2868   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2869   for examples.
  2870 
  2871 
  2872 *** HOLCF ***
  2873 
  2874 * Streams now come with concatenation and are part of the HOLCF image
  2875 
  2876 
  2877 
  2878 New in Isabelle2003 (May 2003)
  2879 ------------------------------
  2880 
  2881 *** General ***
  2882 
  2883 * Provers/simplifier:
  2884 
  2885   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2886     Assumptions are now subject to complete mutual simplification,
  2887     not just from left to right. The simplifier now preserves
  2888     the order of assumptions.
  2889 
  2890     Potential INCOMPATIBILITY:
  2891 
  2892     -- simp sometimes diverges where the old version did
  2893        not, e.g. invoking simp on the goal
  2894 
  2895         [| P (f x); y = x; f x = f y |] ==> Q
  2896 
  2897        now gives rise to the infinite reduction sequence
  2898 
  2899         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2900 
  2901        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2902        kind of problem.
  2903 
  2904     -- Tactics combining classical reasoner and simplification (such as auto)
  2905        are also affected by this change, because many of them rely on
  2906        simp. They may sometimes diverge as well or yield a different numbers
  2907        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2908        in case of problems. Sometimes subsequent calls to the classical
  2909        reasoner will fail because a preceeding call to the simplifier too
  2910        eagerly simplified the goal, e.g. deleted redundant premises.
  2911 
  2912   - The simplifier trace now shows the names of the applied rewrite rules
  2913 
  2914   - You can limit the number of recursive invocations of the simplifier
  2915     during conditional rewriting (where the simplifie tries to solve the
  2916     conditions before applying the rewrite rule):
  2917     ML "simp_depth_limit := n"
  2918     where n is an integer. Thus you can force termination where previously
  2919     the simplifier would diverge.
  2920 
  2921   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2922 
  2923   - No longer aborts on failed congruence proof.  Instead, the
  2924     congruence is ignored.
  2925 
  2926 * Pure: New generic framework for extracting programs from constructive
  2927   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2928   as HOL/Extraction for some case studies.
  2929 
  2930 * Pure: The main goal of the proof state is no longer shown by default, only
  2931 the subgoals. This behaviour is controlled by a new flag.
  2932    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2933 (ML: Proof.show_main_goal).
  2934 
  2935 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2936 rules whose conclusion matches subgoal 1:
  2937       PG menu: Isabelle/Isar -> Show me -> matching rules
  2938 The rules are ordered by how closely they match the subgoal.
  2939 In particular, rules that solve a subgoal outright are displayed first
  2940 (or rather last, the way they are printed).
  2941 (ML: ProofGeneral.print_intros())
  2942 
  2943 * Pure: New flag trace_unify_fail causes unification to print
  2944 diagnostic information (PG: in trace buffer) when it fails. This is
  2945 useful for figuring out why single step proofs like rule, erule or
  2946 assumption failed.
  2947 
  2948 * Pure: Locale specifications now produce predicate definitions
  2949 according to the body of text (covering assumptions modulo local
  2950 definitions); predicate "loc_axioms" covers newly introduced text,
  2951 while "loc" is cumulative wrt. all included locale expressions; the
  2952 latter view is presented only on export into the global theory
  2953 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2954 on the old view without predicates;
  2955 
  2956 * Pure: predefined locales "var" and "struct" are useful for sharing
  2957 parameters (as in CASL, for example); just specify something like
  2958 ``var x + var y + struct M'' as import;
  2959 
  2960 * Pure: improved thms_containing: proper indexing of facts instead of
  2961 raw theorems; check validity of results wrt. current name space;
  2962 include local facts of proof configuration (also covers active
  2963 locales), cover fixed variables in index; may use "_" in term
  2964 specification; an optional limit for the number of printed facts may
  2965 be given (the default is 40);
  2966 
  2967 * Pure: disallow duplicate fact bindings within new-style theory files
  2968 (batch-mode only);
  2969 
  2970 * Provers: improved induct method: assumptions introduced by case
  2971 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2972 the goal statement); "foo" still refers to all facts collectively;
  2973 
  2974 * Provers: the function blast.overloaded has been removed: all constants
  2975 are regarded as potentially overloaded, which improves robustness in exchange
  2976 for slight decrease in efficiency;
  2977 
  2978 * Provers/linorder: New generic prover for transitivity reasoning over
  2979 linear orders.  Note: this prover is not efficient!
  2980 
  2981 * Isar: preview of problems to finish 'show' now produce an error
  2982 rather than just a warning (in interactive mode);
  2983 
  2984 
  2985 *** HOL ***
  2986 
  2987 * arith(_tac)
  2988 
  2989  - Produces a counter example if it cannot prove a goal.
  2990    Note that the counter example may be spurious if the goal is not a formula
  2991    of quantifier-free linear arithmetic.
  2992    In ProofGeneral the counter example appears in the trace buffer.
  2993 
  2994  - Knows about div k and mod k where k is a numeral of type nat or int.
  2995 
  2996  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2997    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2998    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2999 
  3000 * simp's arithmetic capabilities have been enhanced a bit: it now
  3001 takes ~= in premises into account (by performing a case split);
  3002 
  3003 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3004 are distributed over a sum of terms;
  3005 
  3006 * New tactic "trans_tac" and method "trans" instantiate
  3007 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3008 "<=", "<" and "=").
  3009 
  3010 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3011 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3012 
  3013 * 'typedef' command has new option "open" to suppress the set
  3014 definition;
  3015 
  3016 * functions Min and Max on finite sets have been introduced (theory
  3017 Finite_Set);
  3018 
  3019 * attribute [symmetric] now works for relations as well; it turns
  3020 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3021 
  3022 * induct over a !!-quantified statement (say !!x1..xn):
  3023   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3024 
  3025 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3026 %x. None. Warning: empty_def now refers to the previously hidden definition
  3027 of the empty set.
  3028 
  3029 * Algebra: formalization of classical algebra.  Intended as base for
  3030 any algebraic development in Isabelle.  Currently covers group theory
  3031 (up to Sylow's theorem) and ring theory (Universal Property of
  3032 Univariate Polynomials).  Contributions welcome;
  3033 
  3034 * GroupTheory: deleted, since its material has been moved to Algebra;
  3035 
  3036 * Complex: new directory of the complex numbers with numeric constants,
  3037 nonstandard complex numbers, and some complex analysis, standard and
  3038 nonstandard (Jacques Fleuriot);
  3039 
  3040 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3041 
  3042 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3043 Fleuriot);
  3044 
  3045 * Real/HahnBanach: updated and adapted to locales;
  3046 
  3047 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3048 Gray and Kramer);
  3049 
  3050 * UNITY: added the Meier-Sanders theory of progress sets;
  3051 
  3052 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3053 as abstract algorithms, instantiated to the JVM;
  3054 
  3055 * Bali: Java source language formalization. Type system, operational
  3056 semantics, axiomatic semantics. Supported language features:
  3057 classes, interfaces, objects,virtual methods, static methods,
  3058 static/instance fields, arrays, access modifiers, definite
  3059 assignment, exceptions.
  3060 
  3061 
  3062 *** ZF ***
  3063 
  3064 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3065 universe, etc.);
  3066 
  3067 * Main ZF: virtually all theories converted to new-style format;
  3068 
  3069 
  3070 *** ML ***
  3071 
  3072 * Pure: Tactic.prove provides sane interface for internal proofs;
  3073 omits the infamous "standard" operation, so this is more appropriate
  3074 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3075 
  3076 * Pure: improved error reporting of simprocs;
  3077 
  3078 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3079 up simprocs;
  3080 
  3081 
  3082 *** Document preparation ***
  3083 
  3084 * uses \par instead of \\ for line breaks in theory text. This may
  3085 shift some page breaks in large documents. To get the old behaviour
  3086 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3087 
  3088 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3089 other packages
  3090 
  3091 * \<euro> now needs package babel/greek instead of marvosym (which
  3092 broke \Rightarrow)
  3093 
  3094 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3095 textcomp package)
  3096 
  3097 
  3098 
  3099 New in Isabelle2002 (March 2002)
  3100 --------------------------------
  3101 
  3102 *** Document preparation ***
  3103 
  3104 * greatly simplified document preparation setup, including more
  3105 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3106 instructive isatool mkdir; users should basically be able to get
  3107 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3108 users may run a separate document processing stage manually like this:
  3109 "isatool usedir -D output HOL Test && isatool document Test/output";
  3110 
  3111 * theory dependency graph may now be incorporated into documents;
  3112 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3113 with \includegraphics of LaTeX;
  3114 
  3115 * proper spacing of consecutive markup elements, especially text
  3116 blocks after section headings;
  3117 
  3118 * support bold style (for single symbols only), input syntax is like
  3119 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3120 
  3121 * \<bullet> is now output as bold \cdot by default, which looks much
  3122 better in printed text;
  3123 
  3124 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3125 note that these symbols are currently unavailable in Proof General /
  3126 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3127 
  3128 * isatool latex no longer depends on changed TEXINPUTS, instead
  3129 isatool document copies the Isabelle style files to the target
  3130 location;
  3131 
  3132 
  3133 *** Isar ***
  3134 
  3135 * Pure/Provers: improved proof by cases and induction;
  3136   - 'case' command admits impromptu naming of parameters (such as
  3137     "case (Suc n)");
  3138   - 'induct' method divinates rule instantiation from the inductive
  3139     claim; no longer requires excessive ?P bindings for proper
  3140     instantiation of cases;
  3141   - 'induct' method properly enumerates all possibilities of set/type
  3142     rules; as a consequence facts may be also passed through *type*
  3143     rules without further ado;
  3144   - 'induct' method now derives symbolic cases from the *rulified*
  3145     rule (before it used to rulify cases stemming from the internal
  3146     atomized version); this means that the context of a non-atomic
  3147     statement becomes is included in the hypothesis, avoiding the
  3148     slightly cumbersome show "PROP ?case" form;
  3149   - 'induct' may now use elim-style induction rules without chaining
  3150     facts, using ``missing'' premises from the goal state; this allows
  3151     rules stemming from inductive sets to be applied in unstructured
  3152     scripts, while still benefitting from proper handling of non-atomic
  3153     statements; NB: major inductive premises need to be put first, all
  3154     the rest of the goal is passed through the induction;
  3155   - 'induct' proper support for mutual induction involving non-atomic
  3156     rule statements (uses the new concept of simultaneous goals, see
  3157     below);
  3158   - append all possible rule selections, but only use the first
  3159     success (no backtracking);
  3160   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3161   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3162   - added 'print_induct_rules' (covered by help item in recent Proof
  3163     General versions);
  3164   - moved induct/cases attributes to Pure, methods to Provers;
  3165   - generic method setup instantiated for FOL and HOL;
  3166 
  3167 * Pure: support multiple simultaneous goal statements, for example
  3168 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3169 meta-level mechanism, this acts as if several individual goals had
  3170 been stated separately; in particular common proof methods need to be
  3171 repeated in order to cover all claims; note that a single elimination
  3172 step is *not* sufficient to establish the two conjunctions, so this
  3173 fails:
  3174 
  3175   assume "A & B" then have A and B ..   (*".." fails*)
  3176 
  3177 better use "obtain" in situations as above; alternative refer to
  3178 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3179 
  3180 * Pure: proper integration with ``locales''; unlike the original
  3181 version by Florian Kammller, Isar locales package high-level proof
  3182 contexts rather than raw logical ones (e.g. we admit to include
  3183 attributes everywhere); operations on locales include merge and
  3184 rename; support for implicit arguments (``structures''); simultaneous
  3185 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3186 some examples;
  3187 
  3188 * Pure: the following commands have been ``localized'', supporting a
  3189 target locale specification "(in name)": 'lemma', 'theorem',
  3190 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3191 stored both within the locale and at the theory level (exported and
  3192 qualified by the locale name);
  3193 
  3194 * Pure: theory goals may now be specified in ``long'' form, with
  3195 ad-hoc contexts consisting of arbitrary locale elements. for example
  3196 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3197 definitions may be given, too); the result is a meta-level rule with
  3198 the context elements being discharged in the obvious way;
  3199 
  3200 * Pure: new proof command 'using' allows to augment currently used
  3201 facts after a goal statement ('using' is syntactically analogous to
  3202 'apply', but acts on the goal's facts only); this allows chained facts
  3203 to be separated into parts given before and after a claim, as in
  3204 ``from a and b have C using d and e <proof>'';
  3205 
  3206 * Pure: renamed "antecedent" case to "rule_context";
  3207 
  3208 * Pure: new 'judgment' command records explicit information about the
  3209 object-logic embedding (used by several tools internally); no longer
  3210 use hard-wired "Trueprop";
  3211 
  3212 * Pure: added 'corollary' command;
  3213 
  3214 * Pure: fixed 'token_translation' command;
  3215 
  3216 * Pure: removed obsolete 'exported' attribute;
  3217 
  3218 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3219 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3220 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3221 
  3222 * Pure: method 'atomize' presents local goal premises as object-level
  3223 statements (atomic meta-level propositions); setup controlled via
  3224 rewrite rules declarations of 'atomize' attribute; example
  3225 application: 'induct' method with proper rule statements in improper
  3226 proof *scripts*;
  3227 
  3228 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3229 now consider the syntactic context of assumptions, giving a better
  3230 chance to get type-inference of the arguments right (this is
  3231 especially important for locales);
  3232 
  3233 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3234 mode;
  3235 
  3236 * Pure/obtain: the formal conclusion "thesis", being marked as
  3237 ``internal'', may no longer be reference directly in the text;
  3238 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3239 situations;
  3240 
  3241 * Pure: generic 'sym' attribute which declares a rule both as pure
  3242 'elim?' and for the 'symmetric' operation;
  3243 
  3244 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3245 text; the fixed correlation with particular command syntax has been
  3246 discontinued;
  3247 
  3248 * Pure: new method 'rules' is particularly well-suited for proof
  3249 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3250 but often produces more compact proof terms with less detours;
  3251 
  3252 * Pure/Provers/classical: simplified integration with pure rule
  3253 attributes and methods; the classical "intro?/elim?/dest?"
  3254 declarations coincide with the pure ones; the "rule" method no longer
  3255 includes classically swapped intros; "intro" and "elim" methods no
  3256 longer pick rules from the context; also got rid of ML declarations
  3257 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3258 INCOMPATIBILITY;
  3259 
  3260 * Provers/classical: attribute 'swapped' produces classical inversions
  3261 of introduction rules;
  3262 
  3263 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3264 rules instead of full simplifier context; 'iff' attribute handles
  3265 conditional rules;
  3266 
  3267 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3268 
  3269 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3270 "(permissive)" option to recover old behavior;
  3271 
  3272 * HOL: 'inductive' no longer features separate (collective) attributes
  3273 for 'intros' (was found too confusing);
  3274 
  3275 * HOL: properly declared induction rules less_induct and
  3276 wf_induct_rule;
  3277 
  3278 
  3279 *** HOL ***
  3280 
  3281 * HOL: moved over to sane numeral syntax; the new policy is as
  3282 follows:
  3283 
  3284   - 0 and 1 are polymorphic constants, which are defined on any
  3285   numeric type (nat, int, real etc.);
  3286 
  3287   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3288   binary representation internally;
  3289 
  3290   - type nat has special constructor Suc, and generally prefers Suc 0
  3291   over 1::nat and Suc (Suc 0) over 2::nat;
  3292 
  3293 This change may cause significant problems of INCOMPATIBILITY; here
  3294 are some hints on converting existing sources:
  3295 
  3296   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3297   entities, so expressions involving "-" (unary or binary minus) need
  3298   to be spaced properly;
  3299 
  3300   - existing occurrences of "1" may need to be constraint "1::nat" or
  3301   even replaced by Suc 0; similar for old "2";
  3302 
  3303   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3304 
  3305   - remove all special provisions on numerals in proofs;
  3306 
  3307 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3308 representation (depends on bin_arith_simps in the default context);
  3309 
  3310 * HOL: symbolic syntax for x^2 (numeral 2);
  3311 
  3312 * HOL: the class of all HOL types is now called "type" rather than
  3313 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3314 in axclass/classes, instance/arities, and (usually rare) occurrences
  3315 in typings (of consts etc.); internally the class is called
  3316 "HOL.type", ML programs should refer to HOLogic.typeS;
  3317 
  3318 * HOL/record package improvements:
  3319   - new derived operations "fields" to build a partial record section,
  3320     "extend" to promote a fixed record to a record scheme, and
  3321     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3322     declared as simp by default;
  3323   - shared operations ("more", "fields", etc.) now need to be always
  3324     qualified) --- potential INCOMPATIBILITY;
  3325   - removed "make_scheme" operations (use "make" with "extend") --
  3326     INCOMPATIBILITY;
  3327   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3328   - provides cases/induct rules for use with corresponding Isar
  3329     methods (for concrete records, record schemes, concrete more
  3330     parts, and schematic more parts -- in that order);
  3331   - internal definitions directly based on a light-weight abstract
  3332     theory of product types over typedef rather than datatype;
  3333 
  3334 * HOL: generic code generator for generating executable ML code from
  3335 specifications; specific support for HOL constructs such as inductive
  3336 datatypes and sets, as well as recursive functions; can be invoked
  3337 via 'generate_code' theory section;
  3338 
  3339 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3340 
  3341 * HOL: consolidated and renamed several theories.  In particular:
  3342         Ord.thy has been absorbed into HOL.thy
  3343         String.thy has been absorbed into List.thy
  3344 
  3345 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3346 (beware of argument permutation!);
  3347 
  3348 * HOL: linorder_less_split superseded by linorder_cases;
  3349 
  3350 * HOL/List: "nodups" renamed to "distinct";
  3351 
  3352 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3353 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3354   - Ex_def has changed, now need to use some_eq_ex
  3355 
  3356 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3357 in this (rare) case use:
  3358 
  3359   delSWrapper "split_all_tac"
  3360   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3361 
  3362 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3363 MAY FAIL;
  3364 
  3365 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3366 Isabelle's type classes, ^ on functions and relations has too general
  3367 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3368 necessary to attach explicit type constraints;
  3369 
  3370 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3371 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3372 renamed accordingly (eg "compI" -> "rel_compI").
  3373 
  3374 * HOL: syntax translations now work properly with numerals and records
  3375 expressions;
  3376 
  3377 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3378 of "lam" -- INCOMPATIBILITY;
  3379 
  3380 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3381 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3382 renamed "Product_Type.unit";
  3383 
  3384 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3385 
  3386 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3387 the "cases" method);
  3388 
  3389 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3390 Florian Kammller);
  3391 
  3392 * HOL/IMP: updated and converted to new-style theory format; several
  3393 parts turned into readable document, with proper Isar proof texts and
  3394 some explanations (by Gerwin Klein);
  3395 
  3396 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3397 
  3398 * HOL-Hyperreal is now a logic image;
  3399 
  3400 
  3401 *** HOLCF ***
  3402 
  3403 * Isar: consts/constdefs supports mixfix syntax for continuous
  3404 operations;
  3405 
  3406 * Isar: domain package adapted to new-style theory format, e.g. see
  3407 HOLCF/ex/Dnat.thy;
  3408 
  3409 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3410 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3411 lift.induct_tac, always use UU instead of Undef;
  3412 
  3413 * HOLCF/IMP: updated and converted to new-style theory;
  3414 
  3415 
  3416 *** ZF ***
  3417 
  3418 * Isar: proper integration of logic-specific tools and packages,
  3419 including theory commands '(co)inductive', '(co)datatype',
  3420 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3421 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3422 
  3423 * theory Main no longer includes AC; for the Axiom of Choice, base
  3424 your theory on Main_ZFC;
  3425 
  3426 * the integer library now covers quotients and remainders, with many
  3427 laws relating division to addition, multiplication, etc.;
  3428 
  3429 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3430 typeless version of the formalism;
  3431 
  3432 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3433 format;
  3434 
  3435 * ZF/Induct: new directory for examples of inductive definitions,
  3436 including theory Multiset for multiset orderings; converted to
  3437 new-style theory format;
  3438 
  3439 * ZF: many new theorems about lists, ordinals, etc.;
  3440 
  3441 
  3442 *** General ***
  3443 
  3444 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3445 variable proof controls level of detail: 0 = no proofs (only oracle
  3446 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3447 also ref manual for further ML interfaces;
  3448 
  3449 * Pure/axclass: removed obsolete ML interface
  3450 goal_subclass/goal_arity;
  3451 
  3452 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3453 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3454 separate tokens, so expressions involving minus need to be spaced
  3455 properly;
  3456 
  3457 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3458 rather than "infixl" or "infixr";
  3459 
  3460 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3461 sort constraint specifications in type inference; e.g. "x::_::foo"
  3462 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3463 type variable);
  3464 
  3465 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3466 control output of nested => (types); the default behavior is
  3467 "type_brackets";
  3468 
  3469 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3470 tokens into AST constants;
  3471 
  3472 * Pure/syntax: prefer later declarations of translations and print
  3473 translation functions; potential INCOMPATIBILITY: need to reverse
  3474 multiple declarations for same syntax element constant;
  3475 
  3476 * Pure/show_hyps reset by default (in accordance to existing Isar
  3477 practice);
  3478 
  3479 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3480 addSafter;
  3481 
  3482 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3483 as well;
  3484 
  3485 * system: tested support for MacOS X; should be able to get Isabelle +
  3486 Proof General to work in a plain Terminal after installing Poly/ML
  3487 (e.g. from the Isabelle distribution area) and GNU bash alone
  3488 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3489 support requires further installations, e.g. from
  3490 http://fink.sourceforge.net/);
  3491 
  3492 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3493 
  3494 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3495 of 40 MB), cf. ML_OPTIONS;
  3496 
  3497 * system: Proof General keywords specification is now part of the
  3498 Isabelle distribution (see etc/isar-keywords.el);
  3499 
  3500 * system: support for persistent Proof General sessions (refrain from
  3501 outdating all loaded theories on startup); user may create writable
  3502 logic images like this: ``isabelle -q HOL Test'';
  3503 
  3504 * system: smart selection of Isabelle process versus Isabelle
  3505 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3506 run both "isabelle" and "Isabelle" even if file names are badly
  3507 damaged (executable inspects the case of the first letter of its own
  3508 name); added separate "isabelle-process" and "isabelle-interface";
  3509 
  3510 * system: refrain from any attempt at filtering input streams; no
  3511 longer support ``8bit'' encoding of old isabelle font, instead proper
  3512 iso-latin characters may now be used; the related isatools
  3513 "symbolinput" and "nonascii" have disappeared as well;
  3514 
  3515 * system: removed old "xterm" interface (the print modes "xterm" and
  3516 "xterm_color" are still available for direct use in a suitable
  3517 terminal);
  3518 
  3519 
  3520 
  3521 New in Isabelle99-2 (February 2001)
  3522 -----------------------------------
  3523 
  3524 *** Overview of INCOMPATIBILITIES ***
  3525 
  3526 * HOL: please note that theories in the Library and elsewhere often use the
  3527 new-style (Isar) format; to refer to their theorems in an ML script you must
  3528 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3529 
  3530 * HOL: inductive package no longer splits induction rule aggressively,
  3531 but only as far as specified by the introductions given; the old
  3532 format may be recovered via ML function complete_split_rule or attribute
  3533 'split_rule (complete)';
  3534 
  3535 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3536 gfp_Tarski to gfp_unfold;
  3537 
  3538 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3539 
  3540 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3541 relation); infix "^^" has been renamed "``"; infix "``" has been
  3542 renamed "`"; "univalent" has been renamed "single_valued";
  3543 
  3544 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3545 operation;
  3546 
  3547 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3548 
  3549 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3550 
  3551 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3552 consequence, it is no longer monotonic wrt. the local goal context
  3553 (which is now passed through the inductive cases);
  3554 
  3555 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3556 \<gg> to \<ggreater>;
  3557 
  3558 
  3559 *** Document preparation ***
  3560 
  3561 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3562 available: are "it" for near math-mode best-style output, "sl" for
  3563 slanted text style, and "tt" for plain type-writer; if no
  3564 \isabellestyle command is given, output is according to slanted
  3565 type-writer);
  3566 
  3567 * support sub/super scripts (for single symbols only), input syntax is
  3568 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3569 
  3570 * some more standard symbols; see Appendix A of the system manual for
  3571 the complete list of symbols defined in isabellesym.sty;
  3572 
  3573 * improved isabelle style files; more abstract symbol implementation
  3574 (should now use \isamath{...} and \isatext{...} in custom symbol
  3575 definitions);
  3576 
  3577 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3578 state; Note that presentation of goal states does not conform to
  3579 actual human-readable proof documents.  Please do not include goal
  3580 states into document output unless you really know what you are doing!
  3581 
  3582 * proper indentation of antiquoted output with proportional LaTeX
  3583 fonts;
  3584 
  3585 * no_document ML operator temporarily disables LaTeX document
  3586 generation;
  3587 
  3588 * isatool unsymbolize tunes sources for plain ASCII communication;
  3589 
  3590 
  3591 *** Isar ***
  3592 
  3593 * Pure: Isar now suffers initial goal statements to contain unbound
  3594 schematic variables (this does not conform to actual readable proof
  3595 documents, due to unpredictable outcome and non-compositional proof
  3596 checking); users who know what they are doing may use schematic goals
  3597 for Prolog-style synthesis of proven results;
  3598 
  3599 * Pure: assumption method (an implicit finishing) now handles actual
  3600 rules as well;
  3601 
  3602 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3603 initial goal, declare "that" only as Pure intro (only for single
  3604 steps); the "that" rule assumption may now be involved in implicit
  3605 finishing, thus ".." becomes a feasible for trivial obtains;
  3606 
  3607 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3608 instance proofs may be performed by "..";
  3609 
  3610 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3611 statements as well;
  3612 
  3613 * Pure: more robust selection of calculational rules;
  3614 
  3615 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3616 rule (as well as the assumption rule);
  3617 
  3618 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3619 lemmas, using the graph browser tool;
  3620 
  3621 * Pure: predict failure of "show" in interactive mode;
  3622 
  3623 * Pure: 'thms_containing' now takes actual terms as arguments;
  3624 
  3625 * HOL: improved method 'induct' --- now handles non-atomic goals
  3626 (potential INCOMPATIBILITY); tuned error handling;
  3627 
  3628 * HOL: cases and induct rules now provide explicit hints about the
  3629 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3630 any remaining facts are inserted into the goal verbatim;
  3631 
  3632 * HOL: local contexts (aka cases) may now contain term bindings as
  3633 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3634 the result to be shown in each case;
  3635 
  3636 * HOL: added 'recdef_tc' command;
  3637 
  3638 * isatool convert assists in eliminating legacy ML scripts;
  3639 
  3640 
  3641 *** HOL ***
  3642 
  3643 * HOL/Library: a collection of generic theories to be used together
  3644 with main HOL; the theory loader path already includes this directory
  3645 by default; the following existing theories have been moved here:
  3646 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3647 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3648 
  3649 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3650 modelling and verification task performed in Isabelle/HOL +
  3651 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3652 
  3653 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3654 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3655 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3656 'domain', this makes the theory consistent with mathematical
  3657 literature;
  3658 
  3659 * HOL basics: added overloaded operations "inverse" and "divide"
  3660 (infix "/"), syntax for generic "abs" operation, generic summation
  3661 operator \<Sum>;
  3662 
  3663 * HOL/typedef: simplified package, provide more useful rules (see also
  3664 HOL/subset.thy);
  3665 
  3666 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3667 now expressed as a proper nested rule (old-style tactic scripts may
  3668 require atomize_strip_tac to cope with non-atomic premises);
  3669 
  3670 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3671 to "split_conv" (old name still available for compatibility);
  3672 
  3673 * HOL: improved concrete syntax for strings (e.g. allows translation
  3674 rules with string literals);
  3675 
  3676 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3677  and Fleuriot's mechanization of analysis, including the transcendental
  3678  functions for the reals;
  3679 
  3680 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3681 
  3682 
  3683 *** CTT ***
  3684 
  3685 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3686 "lam" is displayed as TWO lambda-symbols
  3687 
  3688 * CTT: theory Main now available, containing everything (that is, Bool
  3689 and Arith);
  3690 
  3691 
  3692 *** General ***
  3693 
  3694 * Pure: the Simplifier has been implemented properly as a derived rule
  3695 outside of the actual kernel (at last!); the overall performance
  3696 penalty in practical applications is about 50%, while reliability of
  3697 the Isabelle inference kernel has been greatly improved;
  3698 
  3699 * print modes "brackets" and "no_brackets" control output of nested =>
  3700 (types) and ==> (props); the default behaviour is "brackets";
  3701 
  3702 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3703 as assumptions as well;
  3704 
  3705 * system: support Poly/ML 4.0;
  3706 
  3707 * system: isatool install handles KDE version 1 or 2;
  3708 
  3709 
  3710 
  3711 New in Isabelle99-1 (October 2000)
  3712 ----------------------------------
  3713 
  3714 *** Overview of INCOMPATIBILITIES ***
  3715 
  3716 * HOL: simplification of natural numbers is much changed; to partly
  3717 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3718 issue the following ML commands:
  3719 
  3720   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3721   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3722 
  3723 * HOL: simplification no longer dives into case-expressions; this is
  3724 controlled by "t.weak_case_cong" for each datatype t;
  3725 
  3726 * HOL: nat_less_induct renamed to less_induct;
  3727 
  3728 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3729 fixsome to patch .thy and .ML sources automatically;
  3730 
  3731   select_equality  -> some_equality
  3732   select_eq_Ex     -> some_eq_ex
  3733   selectI2EX       -> someI2_ex
  3734   selectI2         -> someI2
  3735   selectI          -> someI
  3736   select1_equality -> some1_equality
  3737   Eps_sym_eq       -> some_sym_eq_trivial
  3738   Eps_eq           -> some_eq_trivial
  3739 
  3740 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3741 
  3742 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3743 instead);
  3744 
  3745 * HOL: the recursion equations generated by 'recdef' are now called
  3746 f.simps instead of f.rules;
  3747 
  3748 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3749 
  3750 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3751 sometimes be needed;
  3752 
  3753 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3754 
  3755 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3756 
  3757 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3758 product is now "<*>" instead of "Times"; the lexicographic product is
  3759 now "<*lex*>" instead of "**";
  3760 
  3761 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3762 of main HOL, but was unused); better use HOL's datatype package;
  3763 
  3764 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3765 the old syntax may be recovered as follows:
  3766 
  3767   syntax (symbols)
  3768     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3769       (infixl "\\<oplus>" 100)
  3770 
  3771 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3772 
  3773 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3774 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3775 internally;
  3776 
  3777 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3778 changed from A/r to A//r;
  3779 
  3780 * ZF: new treatment of arithmetic (nat & int) may break some old
  3781 proofs;
  3782 
  3783 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3784 rulify -> rule_format, elimify -> elim_format, ...);
  3785 
  3786 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3787 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3788 should have to change intro!! to intro? only); replaced "delrule" by
  3789 "rule del";
  3790 
  3791 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3792 
  3793 * Provers: strengthened force_tac by using new first_best_tac;
  3794 
  3795 * LaTeX document preparation: several changes of isabelle.sty (see
  3796 lib/texinputs);
  3797 
  3798 
  3799 *** Document preparation ***
  3800 
  3801 * formal comments (text blocks etc.) in new-style theories may now
  3802 contain antiquotations of thm/prop/term/typ/text to be presented
  3803 according to latex print mode; concrete syntax is like this:
  3804 @{term[show_types] "f(x) = a + x"};
  3805 
  3806 * isatool mkdir provides easy setup of Isabelle session directories,
  3807 including proper document sources;
  3808 
  3809 * generated LaTeX sources are now deleted after successful run
  3810 (isatool document -c); may retain a copy somewhere else via -D option
  3811 of isatool usedir;
  3812 
  3813 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3814 style files, achieving self-contained LaTeX sources and simplifying
  3815 LaTeX debugging;
  3816 
  3817 * old-style theories now produce (crude) LaTeX output as well;
  3818 
  3819 * browser info session directories are now self-contained (may be put
  3820 on WWW server seperately); improved graphs of nested sessions; removed
  3821 graph for 'all sessions';
  3822 
  3823 * several improvements in isabelle style files; \isabellestyle{it}
  3824 produces fake math mode output; \isamarkupheader is now \section by
  3825 default; see lib/texinputs/isabelle.sty etc.;
  3826 
  3827 
  3828 *** Isar ***
  3829 
  3830 * Isar/Pure: local results and corresponding term bindings are now
  3831 subject to Hindley-Milner polymorphism (similar to ML); this
  3832 accommodates incremental type-inference very nicely;
  3833 
  3834 * Isar/Pure: new derived language element 'obtain' supports
  3835 generalized existence reasoning;
  3836 
  3837 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3838 support accumulation of results, without applying any rules yet;
  3839 useful to collect intermediate results without explicit name
  3840 references, and for use with transitivity rules with more than 2
  3841 premises;
  3842 
  3843 * Isar/Pure: scalable support for case-analysis type proofs: new
  3844 'case' language element refers to local contexts symbolically, as
  3845 produced by certain proof methods; internally, case names are attached
  3846 to theorems as "tags";
  3847 
  3848 * Isar/Pure: theory command 'hide' removes declarations from
  3849 class/type/const name spaces;
  3850 
  3851 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3852 indicate potential overloading;
  3853 
  3854 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3855 
  3856 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3857 "{a,b,c}" instead of {a,b,c};
  3858 
  3859 * Isar/Pure now provides its own version of intro/elim/dest
  3860 attributes; useful for building new logics, but beware of confusion
  3861 with the version in Provers/classical;
  3862 
  3863 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3864 case name 'antecedent';
  3865 
  3866 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3867 to the current context is now done automatically);
  3868 
  3869 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3870 for definining proof methods in ML;
  3871 
  3872 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3873 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3874 most cases, one should have to change intro!! to intro? only);
  3875 replaced "delrule" by "rule del";
  3876 
  3877 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3878 'symmetric' attribute (the latter supercedes [RS sym]);
  3879 
  3880 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3881 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3882 well (including splits);
  3883 
  3884 * Isar/Provers: Simplifier and Classical methods now support all kind
  3885 of modifiers used in the past, including 'cong', 'iff', etc.
  3886 
  3887 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3888 of Simplifier and Classical reasoner);
  3889 
  3890 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3891 now support named cases; major packages (inductive, datatype, primrec,
  3892 recdef) support case names and properly name parameters;
  3893 
  3894 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3895 monotonicity conditions are extracted to be proven at end of
  3896 calculations;
  3897 
  3898 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3899 method anyway;
  3900 
  3901 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3902 split_if split_if_asm; datatype package provides theorems foo.splits =
  3903 foo.split foo.split_asm for each datatype;
  3904 
  3905 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3906 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3907 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3908 use "(cases (simplified))" method in proper proof texts);
  3909 
  3910 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3911 
  3912 * Isar: names of theorems etc. may be natural numbers as well;
  3913 
  3914 * Isar: 'pr' command: optional arguments for goals_limit and
  3915 ProofContext.prems_limit; no longer prints theory contexts, but only
  3916 proof states;
  3917 
  3918 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3919 additional print modes to be specified; e.g. "pr(latex)" will print
  3920 proof state according to the Isabelle LaTeX style;
  3921 
  3922 * Isar: improved support for emulating tactic scripts, including proof
  3923 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3924 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3925 (for HOL datatypes);
  3926 
  3927 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3928 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3929 'proof method scripts' have to be in depth-first order;
  3930 
  3931 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3932 
  3933 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3934 should instead use individual commands for printing items
  3935 (print_commands, print_methods etc.);
  3936 
  3937 * Isar: added 'nothing' --- the empty list of theorems;
  3938 
  3939 
  3940 *** HOL ***
  3941 
  3942 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3943 corresponding virtual machine and a specification of its bytecode
  3944 verifier and a lightweight bytecode verifier, including proofs of
  3945 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3946 Cornelia Pusch (see also the homepage of project Bali at
  3947 http://isabelle.in.tum.de/Bali/);
  3948 
  3949 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3950 Clemens Ballarin;
  3951 
  3952 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3953 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3954 Rasmussen;
  3955 
  3956 * HOL/Lattice: fundamental concepts of lattice theory and order
  3957 structures, including duals, properties of bounds versus algebraic
  3958 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3959 Theorem for complete lattices etc.; may also serve as a demonstration
  3960 for abstract algebraic reasoning using axiomatic type classes, and
  3961 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3962 
  3963 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3964 von Oheimb;
  3965 
  3966 * HOL/IMPP: extension of IMP with local variables and mutually
  3967 recursive procedures, by David von Oheimb;
  3968 
  3969 * HOL/Lambda: converted into new-style theory and document;
  3970 
  3971 * HOL/ex/Multiquote: example of multiple nested quotations and
  3972 anti-quotations -- basically a generalized version of de-Bruijn
  3973 representation; very useful in avoiding lifting of operations;
  3974 
  3975 * HOL/record: added general record equality rule to simpset; fixed
  3976 select-update simplification procedure to handle extended records as
  3977 well; admit "r" as field name;
  3978 
  3979 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3980 other numeric types and also as the identity of groups, rings, etc.;
  3981 
  3982 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3983 Types nat and int belong to this axclass;
  3984 
  3985 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3986    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3987    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3988   two terms #m*u and #n*u are replaced by #(m+n)*u
  3989     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3990   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3991     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3992 
  3993 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3994 powerful prover for predicate logic but knows nothing of clasets; see
  3995 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3996 
  3997 * HOL: new version of "case_tac" subsumes both boolean case split and
  3998 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3999 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4000 
  4001 * HOL: simplification no longer dives into case-expressions: only the
  4002 selector expression is simplified, but not the remaining arms; to
  4003 enable full simplification of case-expressions for datatype t, you may
  4004 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4005 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4006 
  4007 * HOL/recdef: the recursion equations generated by 'recdef' for
  4008 function 'f' are now called f.simps instead of f.rules; if all
  4009 termination conditions are proved automatically, these simplification
  4010 rules are added to the simpset, as in primrec; rules may be named
  4011 individually as well, resulting in a separate list of theorems for
  4012 each equation;
  4013 
  4014 * HOL/While is a new theory that provides a while-combinator. It
  4015 permits the definition of tail-recursive functions without the
  4016 provision of a termination measure. The latter is necessary once the
  4017 invariant proof rule for while is applied.
  4018 
  4019 * HOL: new (overloaded) notation for the set of elements below/above
  4020 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4021 
  4022 * HOL: theorems impI, allI, ballI bound as "strip";
  4023 
  4024 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4025 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4026 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4027 
  4028 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4029 
  4030 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4031 main HOL, but was unused);
  4032 
  4033 * HOL: fewer consts declared as global (e.g. have to refer to
  4034 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4035 
  4036 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4037 in case of overlap with user translations (e.g. judgements over
  4038 tuples); (note that the underlying logical represenation is still
  4039 bogus);
  4040 
  4041 
  4042 *** ZF ***
  4043 
  4044 * ZF: simplification automatically cancels common terms in arithmetic
  4045 expressions over nat and int;
  4046 
  4047 * ZF: new treatment of nat to minimize type-checking: all operators
  4048 coerce their operands to a natural number using the function natify,
  4049 making the algebraic laws unconditional;
  4050 
  4051 * ZF: as above, for int: operators coerce their operands to an integer
  4052 using the function intify;
  4053 
  4054 * ZF: the integer library now contains many of the usual laws for the
  4055 orderings, including $<=, and monotonicity laws for $+ and $*;
  4056 
  4057 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4058 simplification;
  4059 
  4060 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4061 to the simplifier and classical reasoner simultaneously;
  4062 
  4063 
  4064 *** General ***
  4065 
  4066 * Provers: blast_tac now handles actual object-logic rules as
  4067 assumptions; note that auto_tac uses blast_tac internally as well;
  4068 
  4069 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4070 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4071 
  4072 * Provers: delrules now handles destruct rules as well (no longer need
  4073 explicit make_elim);
  4074 
  4075 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4076   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4077 use instead the strong form,
  4078   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4079 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4080 from destruct-rules;
  4081 
  4082 * Provers: Simplifier.easy_setup provides a fast path to basic
  4083 Simplifier setup for new object-logics;
  4084 
  4085 * Pure: AST translation rules no longer require constant head on LHS;
  4086 
  4087 * Pure: improved name spaces: ambiguous output is qualified; support
  4088 for hiding of names;
  4089 
  4090 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4091 XSYMBOL_HOME; no longer need to do manual configuration in most
  4092 situations;
  4093 
  4094 * system: compression of ML heaps images may now be controlled via -c
  4095 option of isabelle and isatool usedir (currently only observed by
  4096 Poly/ML);
  4097 
  4098 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4099 useful for remote X11);
  4100 
  4101 * system: provide TAGS file for Isabelle sources;
  4102 
  4103 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4104 order;
  4105 
  4106 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4107 timing flag supersedes proof_timing and Toplevel.trace;
  4108 
  4109 * ML: new combinators |>> and |>>> for incremental transformations
  4110 with secondary results (e.g. certain theory extensions):
  4111 
  4112 * ML: PureThy.add_defs gets additional argument to indicate potential
  4113 overloading (usually false);
  4114 
  4115 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4116 results;
  4117 
  4118 
  4119 
  4120 New in Isabelle99 (October 1999)
  4121 --------------------------------
  4122 
  4123 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4124 
  4125 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4126 are no longer simplified.  (This allows the simplifier to unfold recursive
  4127 functional programs.)  To restore the old behaviour, declare
  4128 
  4129     Delcongs [if_weak_cong];
  4130 
  4131 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4132 complement;
  4133 
  4134 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4135 
  4136 * HOL/datatype: mutual_induct_tac no longer exists --
  4137   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4138 
  4139 * HOL/typedef: fixed type inference for representing set; type
  4140 arguments now have to occur explicitly on the rhs as type constraints;
  4141 
  4142 * ZF: The con_defs part of an inductive definition may no longer refer
  4143 to constants declared in the same theory;
  4144 
  4145 * HOL, ZF: the function mk_cases, generated by the inductive
  4146 definition package, has lost an argument.  To simplify its result, it
  4147 uses the default simpset instead of a supplied list of theorems.
  4148 
  4149 * HOL/List: the constructors of type list are now Nil and Cons;
  4150 
  4151 * Simplifier: the type of the infix ML functions
  4152         setSSolver addSSolver setSolver addSolver
  4153 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4154 for packaging solvers. A solver is created via
  4155         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4156 where the string argument is only a comment.
  4157 
  4158 
  4159 *** Proof tools ***
  4160 
  4161 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4162 decision procedure for linear arithmetic. Currently it is used for
  4163 types `nat', `int', and `real' in HOL (see below); it can, should and
  4164 will be instantiated for other types and logics as well.
  4165 
  4166 * The simplifier now accepts rewrite rules with flexible heads, eg
  4167      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4168   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4169   matching.
  4170 
  4171 
  4172 *** General ***
  4173 
  4174 * New Isabelle/Isar subsystem provides an alternative to traditional
  4175 tactical theorem proving; together with the ProofGeneral/isar user
  4176 interface it offers an interactive environment for developing human
  4177 readable proof documents (Isar == Intelligible semi-automated
  4178 reasoning); for further information see isatool doc isar-ref,
  4179 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4180 
  4181 * improved and simplified presentation of theories: better HTML markup
  4182 (including colors), graph views in several sizes; isatool usedir now
  4183 provides a proper interface for user theories (via -P option); actual
  4184 document preparation based on (PDF)LaTeX is available as well (for
  4185 new-style theories only); see isatool doc system for more information;
  4186 
  4187 * native support for Proof General, both for classic Isabelle and
  4188 Isabelle/Isar;
  4189 
  4190 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4191 using the graph browser tool;
  4192 
  4193 * Isabelle manuals now also available as PDF;
  4194 
  4195 * theory loader rewritten from scratch (may not be fully
  4196 bug-compatible); old loadpath variable has been replaced by show_path,
  4197 add_path, del_path, reset_path functions; new operations such as
  4198 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4199 isatool doc ref);
  4200 
  4201 * improved isatool install: option -k creates KDE application icon,
  4202 option -p DIR installs standalone binaries;
  4203 
  4204 * added ML_PLATFORM setting (useful for cross-platform installations);
  4205 more robust handling of platform specific ML images for SML/NJ;
  4206 
  4207 * the settings environment is now statically scoped, i.e. it is never
  4208 created again in sub-processes invoked from isabelle, isatool, or
  4209 Isabelle;
  4210 
  4211 * path element specification '~~' refers to '$ISABELLE_HOME';
  4212 
  4213 * in locales, the "assumes" and "defines" parts may be omitted if
  4214 empty;
  4215 
  4216 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4217 long arrows);
  4218 
  4219 * new print_mode "HTML";
  4220 
  4221 * new flag show_tags controls display of tags of theorems (which are
  4222 basically just comments that may be attached by some tools);
  4223 
  4224 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4225 mode and goal output format:
  4226 
  4227 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4228 244c244
  4229 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4230 ---
  4231 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4232 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4233 181c181
  4234 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4235 ---
  4236 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4237 
  4238 * function bind_thms stores lists of theorems (cf. bind_thm);
  4239 
  4240 * new shorthand tactics ftac, eatac, datac, fatac;
  4241 
  4242 * qed (and friends) now accept "" as result name; in that case the
  4243 theorem is not stored, but proper checks and presentation of the
  4244 result still apply;
  4245 
  4246 * theorem database now also indexes constants "Trueprop", "all",
  4247 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4248 
  4249 
  4250 *** HOL ***
  4251 
  4252 ** HOL arithmetic **
  4253 
  4254 * There are now decision procedures for linear arithmetic over nat and
  4255 int:
  4256 
  4257 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4258 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4259 are treated as atomic; subformulae not involving type `nat' or `int'
  4260 are ignored; quantified subformulae are ignored unless they are
  4261 positive universal or negative existential. The tactic has to be
  4262 invoked by hand and can be a little bit slow. In particular, the
  4263 running time is exponential in the number of occurrences of `min' and
  4264 `max', and `-' on `nat'.
  4265 
  4266 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4267 (negated) (in)equalities among the premises and the conclusion into
  4268 account (i.e. no compound formulae) and does not know about `min' and
  4269 `max', and `-' on `nat'. It is fast and is used automatically by the
  4270 simplifier.
  4271 
  4272 NB: At the moment, these decision procedures do not cope with mixed
  4273 nat/int formulae where the two parts interact, such as `m < n ==>
  4274 int(m) < int(n)'.
  4275 
  4276 * HOL/Numeral provides a generic theory of numerals (encoded
  4277 efficiently as bit strings); setup for types nat/int/real is in place;
  4278 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4279 int, existing theories and proof scripts may require a few additional
  4280 type constraints;
  4281 
  4282 * integer division and remainder can now be performed on constant
  4283 arguments;
  4284 
  4285 * many properties of integer multiplication, division and remainder
  4286 are now available;
  4287 
  4288 * An interface to the Stanford Validity Checker (SVC) is available through the
  4289 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4290 are proved automatically.  SVC must be installed separately, and its results
  4291 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4292 invocation of the underlying oracle).  For SVC see
  4293   http://verify.stanford.edu/SVC
  4294 
  4295 * IsaMakefile: the HOL-Real target now builds an actual image;
  4296 
  4297 
  4298 ** HOL misc **
  4299 
  4300 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4301 (in Isabelle/Isar) -- by Gertrud Bauer;
  4302 
  4303 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4304 analysis for assembly languages with subtypes;
  4305 
  4306 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4307 -- avoids syntactic ambiguities and treats state, transition, and
  4308 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4309 changed syntax and (many) tactics;
  4310 
  4311 * HOL/inductive: Now also handles more general introduction rules such
  4312   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4313   theorems are now maintained within the theory (maintained via the
  4314   "mono" attribute);
  4315 
  4316 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4317   (using function types) such as
  4318 
  4319   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4320 
  4321 * HOL/record: record_simproc (part of the default simpset) takes care
  4322 of selectors applied to updated records; record_split_tac is no longer
  4323 part of the default claset; update_defs may now be removed from the
  4324 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4325 
  4326   claset_ref () := claset() addSWrapper record_split_wrapper;
  4327   Delsimprocs [record_simproc]
  4328 
  4329 * HOL/typedef: fixed type inference for representing set; type
  4330 arguments now have to occur explicitly on the rhs as type constraints;
  4331 
  4332 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4333 names rather than an ML expression;
  4334 
  4335 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4336 supplied later.  Program schemes can be defined, such as
  4337     "While B C s = (if B s then While B C (C s) else s)"
  4338 where the well-founded relation can be chosen after B and C have been given.
  4339 
  4340 * HOL/List: the constructors of type list are now Nil and Cons;
  4341 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4342 course, ML tools referring to List.list.op # etc. have to be adapted;
  4343 
  4344 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4345 disabled by default; run isabelle with option -m HOL to get back to
  4346 the original Gordon/HOL-style output;
  4347 
  4348 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4349 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4350 
  4351 * HOL basic syntax simplified (more orthogonal): all variants of
  4352 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4353 Eps operator is provided as well: "SOME x. P[x]";
  4354 
  4355 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4356 
  4357 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4358 thus available for user theories;
  4359 
  4360 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4361 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4362 time;
  4363 
  4364 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4365 several times and then mp;
  4366 
  4367 
  4368 *** LK ***
  4369 
  4370 * the notation <<...>> is now available as a notation for sequences of
  4371 formulas;
  4372 
  4373 * the simplifier is now installed
  4374 
  4375 * the axiom system has been generalized (thanks to Soren Heilmann)
  4376 
  4377 * the classical reasoner now has a default rule database
  4378 
  4379 
  4380 *** ZF ***
  4381 
  4382 * new primrec section allows primitive recursive functions to be given
  4383 directly (as in HOL) over datatypes and the natural numbers;
  4384 
  4385 * new tactics induct_tac and exhaust_tac for induction (or case
  4386 analysis) over datatypes and the natural numbers;
  4387 
  4388 * the datatype declaration of type T now defines the recursor T_rec;
  4389 
  4390 * simplification automatically does freeness reasoning for datatype
  4391 constructors;
  4392 
  4393 * automatic type-inference, with AddTCs command to insert new
  4394 type-checking rules;
  4395 
  4396 * datatype introduction rules are now added as Safe Introduction rules
  4397 to the claset;
  4398 
  4399 * the syntax "if P then x else y" is now available in addition to
  4400 if(P,x,y);
  4401 
  4402 
  4403 *** Internal programming interfaces ***
  4404 
  4405 * tuned simplifier trace output; new flag debug_simp;
  4406 
  4407 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4408 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4409 
  4410 * AxClass.axclass_tac lost the theory argument;
  4411 
  4412 * tuned current_goals_markers semantics: begin / end goal avoids
  4413 printing empty lines;
  4414 
  4415 * removed prs and prs_fn hook, which was broken because it did not
  4416 include \n in its semantics, forcing writeln to add one
  4417 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4418 string -> unit if you really want to output text without newline;
  4419 
  4420 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4421 plain output, interface builders may have to enable 'isabelle_font'
  4422 mode to get Isabelle font glyphs as before;
  4423 
  4424 * refined token_translation interface; INCOMPATIBILITY: output length
  4425 now of type real instead of int;
  4426 
  4427 * theory loader actions may be traced via new ThyInfo.add_hook
  4428 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4429 your own database of information attached to *whole* theories -- as
  4430 opposed to intra-theory data slots offered via TheoryDataFun;
  4431 
  4432 * proper handling of dangling sort hypotheses (at last!);
  4433 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4434 extra sort hypotheses that can be witnessed from the type signature;
  4435 the force_strip_shyps flag is gone, any remaining shyps are simply
  4436 left in the theorem (with a warning issued by strip_shyps_warning);
  4437 
  4438 
  4439 
  4440 New in Isabelle98-1 (October 1998)
  4441 ----------------------------------
  4442 
  4443 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4444 
  4445 * several changes of automated proof tools;
  4446 
  4447 * HOL: major changes to the inductive and datatype packages, including
  4448 some minor incompatibilities of theory syntax;
  4449 
  4450 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4451 called `inj_on';
  4452 
  4453 * HOL: removed duplicate thms in Arith:
  4454   less_imp_add_less  should be replaced by  trans_less_add1
  4455   le_imp_add_le      should be replaced by  trans_le_add1
  4456 
  4457 * HOL: unary minus is now overloaded (new type constraints may be
  4458 required);
  4459 
  4460 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4461 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4462 now taken as an integer constant.
  4463 
  4464 * Pure: ML function 'theory_of' renamed to 'theory';
  4465 
  4466 
  4467 *** Proof tools ***
  4468 
  4469 * Simplifier:
  4470   1. Asm_full_simp_tac is now more aggressive.
  4471      1. It will sometimes reorient premises if that increases their power to
  4472         simplify.
  4473      2. It does no longer proceed strictly from left to right but may also
  4474         rotate premises to achieve further simplification.
  4475      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4476      old Asm_full_simp_tac in that it does not rotate premises.
  4477   2. The simplifier now knows a little bit about nat-arithmetic.
  4478 
  4479 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4480 allows for selected deletion of wrappers, by introduction of names for
  4481 wrapper functionals.  This implies that addbefore, addSbefore,
  4482 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4483 and that adding two tactics with the same name overwrites the first
  4484 one (emitting a warning).
  4485   type wrapper = (int -> tactic) -> (int -> tactic)
  4486   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4487   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4488   delWrapper, delSWrapper: claset *  string            -> claset
  4489   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4490 
  4491 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4492 semantics; addbefore now affects only the unsafe part of step_tac
  4493 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4494 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4495 by Force_tac;
  4496 
  4497 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4498 compWrapper; added safe wrapper (and access functions for it);
  4499 
  4500 * HOL/split_all_tac is now much faster and fails if there is nothing
  4501 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4502 and the names of the automatically generated variables have changed.
  4503 split_all_tac has moved within claset() from unsafe wrappers to safe
  4504 wrappers, which means that !!-bound variables are split much more
  4505 aggressively, and safe_tac and clarify_tac now split such variables.
  4506 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4507 Note: the same holds for record_split_tac, which does the job of
  4508 split_all_tac for record fields.
  4509 
  4510 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4511 permanently to the default simpset using Addsplits just like
  4512 Addsimps. They can be removed via Delsplits just like
  4513 Delsimps. Lower-case versions are also available.
  4514 
  4515 * HOL/Simplifier: The rule split_if is now part of the default
  4516 simpset. This means that the simplifier will eliminate all occurrences
  4517 of if-then-else in the conclusion of a goal. To prevent this, you can
  4518 either remove split_if completely from the default simpset by
  4519 `Delsplits [split_if]' or remove it in a specific call of the
  4520 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4521 other case splitting rules to/from the default simpset: every datatype
  4522 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4523 t is the name of the datatype).
  4524 
  4525 * Classical reasoner / Simplifier combination: new force_tac (and
  4526 derivatives Force_tac, force) combines rewriting and classical
  4527 reasoning (and whatever other tools) similarly to auto_tac, but is
  4528 aimed to solve the given subgoal completely.
  4529 
  4530 
  4531 *** General ***
  4532 
  4533 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4534 and `goalw': the theory is no longer needed as an explicit argument -
  4535 the current theory context is used; assumptions are no longer returned
  4536 at the ML-level unless one of them starts with ==> or !!; it is
  4537 recommended to convert to these new commands using isatool fixgoal
  4538 (backup your sources first!);
  4539 
  4540 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4541 the current theory context, and 'theory' to lookup stored theories;
  4542 
  4543 * new theory section 'locale' for declaring constants, assumptions and
  4544 definitions that have local scope;
  4545 
  4546 * new theory section 'nonterminals' for purely syntactic types;
  4547 
  4548 * new theory section 'setup' for generic ML setup functions
  4549 (e.g. package initialization);
  4550 
  4551 * the distribution now includes Isabelle icons: see
  4552 lib/logo/isabelle-{small,tiny}.xpm;
  4553 
  4554 * isatool install - install binaries with absolute references to
  4555 ISABELLE_HOME/bin;
  4556 
  4557 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4558 
  4559 * print mode 'emacs' reserved for Isamode;
  4560 
  4561 * support multiple print (ast) translations per constant name;
  4562 
  4563 * theorems involving oracles are now printed with a suffixed [!];
  4564 
  4565 
  4566 *** HOL ***
  4567 
  4568 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4569 
  4570 * HOL/inductive package reorganized and improved: now supports mutual
  4571 definitions such as
  4572 
  4573   inductive EVEN ODD
  4574     intrs
  4575       null "0 : EVEN"
  4576       oddI "n : EVEN ==> Suc n : ODD"
  4577       evenI "n : ODD ==> Suc n : EVEN"
  4578 
  4579 new theorem list "elims" contains an elimination rule for each of the
  4580 recursive sets; inductive definitions now handle disjunctive premises
  4581 correctly (also ZF);
  4582 
  4583 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4584 "mutual_induct" no longer exists - the induction rule is always
  4585 contained in "induct";
  4586 
  4587 
  4588 * HOL/datatype package re-implemented and greatly improved: now
  4589 supports mutually recursive datatypes such as
  4590 
  4591   datatype
  4592     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4593             | SUM ('a aexp) ('a aexp)
  4594             | DIFF ('a aexp) ('a aexp)
  4595             | NUM 'a
  4596   and
  4597     'a bexp = LESS ('a aexp) ('a aexp)
  4598             | AND ('a bexp) ('a bexp)
  4599             | OR ('a bexp) ('a bexp)
  4600 
  4601 as well as indirectly recursive datatypes such as
  4602 
  4603   datatype
  4604     ('a, 'b) term = Var 'a
  4605                   | App 'b ((('a, 'b) term) list)
  4606 
  4607 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4608 induction on mutually / indirectly recursive datatypes.
  4609 
  4610 Primrec equations are now stored in theory and can be accessed via
  4611 <function_name>.simps.
  4612 
  4613 INCOMPATIBILITIES:
  4614 
  4615   - Theories using datatypes must now have theory Datatype as an
  4616     ancestor.
  4617   - The specific <typename>.induct_tac no longer exists - use the
  4618     generic induct_tac instead.
  4619   - natE has been renamed to nat.exhaust - use exhaust_tac
  4620     instead of res_inst_tac ... natE. Note that the variable
  4621     names in nat.exhaust differ from the names in natE, this
  4622     may cause some "fragile" proofs to fail.
  4623   - The theorems split_<typename>_case and split_<typename>_case_asm
  4624     have been renamed to <typename>.split and <typename>.split_asm.
  4625   - Since default sorts of type variables are now handled correctly,
  4626     some datatype definitions may have to be annotated with explicit
  4627     sort constraints.
  4628   - Primrec definitions no longer require function name and type
  4629     of recursive argument.
  4630 
  4631 Consider using isatool fixdatatype to adapt your theories and proof
  4632 scripts to the new package (backup your sources first!).
  4633 
  4634 
  4635 * HOL/record package: considerably improved implementation; now
  4636 includes concrete syntax for record types, terms, updates; theorems
  4637 for surjective pairing and splitting !!-bound record variables; proof
  4638 support is as follows:
  4639 
  4640   1) standard conversions (selectors or updates applied to record
  4641 constructor terms) are part of the standard simpset;
  4642 
  4643   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4644 made part of standard simpset and claset via addIffs;
  4645 
  4646   3) a tactic for record field splitting (record_split_tac) is part of
  4647 the standard claset (addSWrapper);
  4648 
  4649 To get a better idea about these rules you may retrieve them via
  4650 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4651 the name of your record type.
  4652 
  4653 The split tactic 3) conceptually simplifies by the following rule:
  4654 
  4655   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4656 
  4657 Thus any record variable that is bound by meta-all will automatically
  4658 blow up into some record constructor term, consequently the
  4659 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4660 solve record problems automatically.
  4661 
  4662 
  4663 * reorganized the main HOL image: HOL/Integ and String loaded by
  4664 default; theory Main includes everything;
  4665 
  4666 * automatic simplification of integer sums and comparisons, using cancellation;
  4667 
  4668 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4669 
  4670 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4671 
  4672 * many new identities for unions, intersections, set difference, etc.;
  4673 
  4674 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4675 called split_if, split_split, split_sum_case and split_nat_case (to go
  4676 with add/delsplits);
  4677 
  4678 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4679 (?x::unit) = (); this is made part of the default simpset, which COULD
  4680 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4681 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4682 unit_abs_eta_conv is added in order to counter the effect of
  4683 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4684 %u.f();
  4685 
  4686 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4687 makes more sense);
  4688 
  4689 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4690   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4691   disjointness reasoning but breaking a few old proofs.
  4692 
  4693 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4694 to 'converse' from 'inverse' (for compatibility with ZF and some
  4695 literature);
  4696 
  4697 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4698 the well-founded relation;
  4699 
  4700 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4701     Compl A.  The "Compl" syntax remains available as input syntax for this
  4702     release ONLY.
  4703 
  4704 * HOL/Update: new theory of function updates:
  4705     f(a:=b) == %x. if x=a then b else f x
  4706 may also be iterated as in f(a:=b,c:=d,...);
  4707 
  4708 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4709 
  4710 * HOL/List:
  4711   - new function list_update written xs[i:=v] that updates the i-th
  4712     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4713   - new function `upt' written [i..j(] which generates the list
  4714     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4715     bound write [i..j], which is a shorthand for [i..j+1(].
  4716   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4717 
  4718 * HOL/Arith:
  4719   - removed 'pred' (predecessor) function;
  4720   - generalized some theorems about n-1;
  4721   - many new laws about "div" and "mod";
  4722   - new laws about greatest common divisors (see theory ex/Primes);
  4723 
  4724 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4725 instead of "inverse";
  4726 
  4727 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4728   of the multiset ordering;
  4729 
  4730 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4731   (not included by default);
  4732 
  4733 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4734 
  4735 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4736   programs, i.e. different program variables may have different types.
  4737 
  4738 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4739   [previously, this check worked only if the rewrite rule was unconditional]
  4740   Now rew can involve either definitions or equalities (either == or =).
  4741 
  4742 
  4743 *** ZF ***
  4744 
  4745 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4746   only the theorems proved on ZF.ML;
  4747 
  4748 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4749   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4750   disjointness reasoning but breaking a few old proofs.
  4751 
  4752 * ZF/Update: new theory of function updates
  4753     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4754   may also be iterated as in f(a:=b,c:=d,...);
  4755 
  4756 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4757 
  4758 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4759   [previously, this check worked only if the rewrite rule was unconditional]
  4760   Now rew can involve either definitions or equalities (either == or =).
  4761 
  4762 * case_tac provided for compatibility with HOL
  4763     (like the old excluded_middle_tac, but with subgoals swapped)
  4764 
  4765 
  4766 *** Internal programming interfaces ***
  4767 
  4768 * Pure: several new basic modules made available for general use, see
  4769 also src/Pure/README;
  4770 
  4771 * improved the theory data mechanism to support encapsulation (data
  4772 kind name replaced by private Object.kind, acting as authorization
  4773 key); new type-safe user interface via functor TheoryDataFun; generic
  4774 print_data function becomes basically useless;
  4775 
  4776 * removed global_names compatibility flag -- all theory declarations
  4777 are qualified by default;
  4778 
  4779 * module Pure/Syntax now offers quote / antiquote translation
  4780 functions (useful for Hoare logic etc. with implicit dependencies);
  4781 see HOL/ex/Antiquote for an example use;
  4782 
  4783 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4784 cterm -> thm;
  4785 
  4786 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4787 subgoal;
  4788 
  4789 * Display.print_goals function moved to Locale.print_goals;
  4790 
  4791 * standard print function for goals supports current_goals_markers
  4792 variable for marking begin of proof, end of proof, start of goal; the
  4793 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4794 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4795 for example;
  4796 
  4797 
  4798 
  4799 New in Isabelle98 (January 1998)
  4800 --------------------------------
  4801 
  4802 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4803 
  4804 * changed lexical syntax of terms / types: dots made part of long
  4805 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4806 
  4807 * simpset (and claset) reference variable replaced by functions
  4808 simpset / simpset_ref;
  4809 
  4810 * no longer supports theory aliases (via merge) and non-trivial
  4811 implicit merge of thms' signatures;
  4812 
  4813 * most internal names of constants changed due to qualified names;
  4814 
  4815 * changed Pure/Sequence interface (see Pure/seq.ML);
  4816 
  4817 
  4818 *** General Changes ***
  4819 
  4820 * hierachically structured name spaces (for consts, types, axms, thms
  4821 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4822 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4823 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4824 long_names for fully qualified output names; NOTE: ML programs
  4825 (special tactics, packages etc.) referring to internal names may have
  4826 to be adapted to cope with fully qualified names; in case of severe
  4827 backward campatibility problems try setting 'global_names' at compile
  4828 time to have enrything declared within a flat name space; one may also
  4829 fine tune name declarations in theories via the 'global' and 'local'
  4830 section;
  4831 
  4832 * reimplemented the implicit simpset and claset using the new anytype
  4833 data filed in signatures; references simpset:simpset ref etc. are
  4834 replaced by functions simpset:unit->simpset and
  4835 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4836 to patch your ML files accordingly;
  4837 
  4838 * HTML output now includes theory graph data for display with Java
  4839 applet or isatool browser; data generated automatically via isatool
  4840 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4841 
  4842 * defs may now be conditional; improved rewrite_goals_tac to handle
  4843 conditional equations;
  4844 
  4845 * defs now admits additional type arguments, using TYPE('a) syntax;
  4846 
  4847 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4848 creates a new theory node; implicit merge of thms' signatures is
  4849 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4850 transfer:theory->thm->thm in (rare) cases;
  4851 
  4852 * improved handling of draft signatures / theories; draft thms (and
  4853 ctyps, cterms) are automatically promoted to real ones;
  4854 
  4855 * slightly changed interfaces for oracles: admit many per theory, named
  4856 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4857 
  4858 * print_goals: optional output of const types (set show_consts and
  4859 show_types);
  4860 
  4861 * improved output of warnings (###) and errors (***);
  4862 
  4863 * subgoal_tac displays a warning if the new subgoal has type variables;
  4864 
  4865 * removed old README and Makefiles;
  4866 
  4867 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4868 
  4869 * removed obsolete init_pps and init_database;
  4870 
  4871 * deleted the obsolete tactical STATE, which was declared by
  4872     fun STATE tacfun st = tacfun st st;
  4873 
  4874 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4875 (which abbreviates $HOME);
  4876 
  4877 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4878 use isatool fixseq to adapt your ML programs (this works for fully
  4879 qualified references to the Sequence structure only!);
  4880 
  4881 * use_thy no longer requires writable current directory; it always
  4882 reloads .ML *and* .thy file, if either one is out of date;
  4883 
  4884 
  4885 *** Classical Reasoner ***
  4886 
  4887 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4888 tactics that use classical reasoning to simplify a subgoal without
  4889 splitting it into several subgoals;
  4890 
  4891 * Safe_tac: like safe_tac but uses the default claset;
  4892 
  4893 
  4894 *** Simplifier ***
  4895 
  4896 * added simplification meta rules:
  4897     (asm_)(full_)simplify: simpset -> thm -> thm;
  4898 
  4899 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4900 logics (again);
  4901 
  4902 * added prems argument to simplification procedures;
  4903 
  4904 * HOL, FOL, ZF: added infix function `addsplits':
  4905   instead of `<simpset> setloop (split_tac <thms>)'
  4906   you can simply write `<simpset> addsplits <thms>'
  4907 
  4908 
  4909 *** Syntax ***
  4910 
  4911 * TYPE('a) syntax for type reflection terms;
  4912 
  4913 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4914 
  4915 * pretty printer: changed order of mixfix annotation preference (again!);
  4916 
  4917 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4918 
  4919 
  4920 *** HOL ***
  4921 
  4922 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4923   with `addloop' of the simplifier to faciliate case splitting in premises.
  4924 
  4925 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4926 
  4927 * HOL/Auth: new protocol proofs including some for the Internet
  4928   protocol TLS;
  4929 
  4930 * HOL/Map: new theory of `maps' a la VDM;
  4931 
  4932 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4933 cancelling out common nat summands from =, <, <= (in)equalities, or
  4934 differences; simplification procedures nat_cancel_factor for
  4935 cancelling common factor from =, <, <= (in)equalities over natural
  4936 sums; nat_cancel contains both kinds of procedures, it is installed by
  4937 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4938 
  4939 * HOL/simplifier: terms of the form
  4940   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4941   are rewritten to
  4942   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4943   and those of the form
  4944   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4945   are rewritten to
  4946   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4947 
  4948 * HOL/datatype
  4949   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4950 
  4951   P(t_case f1 ... fn x) =
  4952      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4953         ...
  4954        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4955      )
  4956 
  4957   and a theorem `split_t_case_asm' of the form
  4958 
  4959   P(t_case f1 ... fn x) =
  4960     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4961         ...
  4962        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4963      )
  4964   which can be added to a simpset via `addsplits'. The existing theorems
  4965   expand_list_case and expand_option_case have been renamed to
  4966   split_list_case and split_option_case.
  4967 
  4968 * HOL/Arithmetic:
  4969   - `pred n' is automatically converted to `n-1'.
  4970     Users are strongly encouraged not to use `pred' any longer,
  4971     because it will disappear altogether at some point.
  4972   - Users are strongly encouraged to write "0 < n" rather than
  4973     "n ~= 0". Theorems and proof tools have been modified towards this
  4974     `standard'.
  4975 
  4976 * HOL/Lists:
  4977   the function "set_of_list" has been renamed "set" (and its theorems too);
  4978   the function "nth" now takes its arguments in the reverse order and
  4979   has acquired the infix notation "!" as in "xs!n".
  4980 
  4981 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4982 
  4983 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4984   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4985 
  4986 * HOL/record: extensible records with schematic structural subtyping
  4987 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4988 still lacks various theorems and concrete record syntax;
  4989 
  4990 
  4991 *** HOLCF ***
  4992 
  4993 * removed "axioms" and "generated by" sections;
  4994 
  4995 * replaced "ops" section by extended "consts" section, which is capable of
  4996   handling the continuous function space "->" directly;
  4997 
  4998 * domain package:
  4999   . proves theorems immediately and stores them in the theory,
  5000   . creates hierachical name space,
  5001   . now uses normal mixfix annotations (instead of cinfix...),
  5002   . minor changes to some names and values (for consistency),
  5003   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5004   . separator between mutual domain defs: changed "," to "and",
  5005   . improved handling of sort constraints;  now they have to
  5006     appear on the left-hand side of the equations only;
  5007 
  5008 * fixed LAM <x,y,zs>.b syntax;
  5009 
  5010 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5011 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5012 
  5013 
  5014 *** FOL and ZF ***
  5015 
  5016 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5017   with `addloop' of the simplifier to faciliate case splitting in premises.
  5018 
  5019 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5020 in HOL, they strip ALL and --> from proved theorems;
  5021 
  5022 
  5023 
  5024 New in Isabelle94-8 (May 1997)
  5025 ------------------------------
  5026 
  5027 *** General Changes ***
  5028 
  5029 * new utilities to build / run / maintain Isabelle etc. (in parts
  5030 still somewhat experimental); old Makefiles etc. still functional;
  5031 
  5032 * new 'Isabelle System Manual';
  5033 
  5034 * INSTALL text, together with ./configure and ./build scripts;
  5035 
  5036 * reimplemented type inference for greater efficiency, better error
  5037 messages and clean internal interface;
  5038 
  5039 * prlim command for dealing with lots of subgoals (an easier way of
  5040 setting goals_limit);
  5041 
  5042 
  5043 *** Syntax ***
  5044 
  5045 * supports alternative (named) syntax tables (parser and pretty
  5046 printer); internal interface is provided by add_modesyntax(_i);
  5047 
  5048 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5049 be used in conjunction with the Isabelle symbol font; uses the
  5050 "symbols" syntax table;
  5051 
  5052 * added token_translation interface (may translate name tokens in
  5053 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5054 the current print_mode); IMPORTANT: user print translation functions
  5055 are responsible for marking newly introduced bounds
  5056 (Syntax.mark_boundT);
  5057 
  5058 * token translations for modes "xterm" and "xterm_color" that display
  5059 names in bold, underline etc. or colors (which requires a color
  5060 version of xterm);
  5061 
  5062 * infixes may now be declared with names independent of their syntax;
  5063 
  5064 * added typed_print_translation (like print_translation, but may
  5065 access type of constant);
  5066 
  5067 
  5068 *** Classical Reasoner ***
  5069 
  5070 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5071 some limitations.  Blast_tac...
  5072   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5073   + ignores elimination rules that don't have the correct format
  5074         (the conclusion MUST be a formula variable)
  5075   + ignores types, which can make HOL proofs fail
  5076   + rules must not require higher-order unification, e.g. apply_type in ZF
  5077     [message "Function Var's argument not a bound variable" relates to this]
  5078   + its proof strategy is more general but can actually be slower
  5079 
  5080 * substitution with equality assumptions no longer permutes other
  5081 assumptions;
  5082 
  5083 * minor changes in semantics of addafter (now called addaltern); renamed
  5084 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5085 (and access functions for it);
  5086 
  5087 * improved combination of classical reasoner and simplifier:
  5088   + functions for handling clasimpsets
  5089   + improvement of addss: now the simplifier is called _after_ the
  5090     safe steps.
  5091   + safe variant of addss called addSss: uses safe simplifications
  5092     _during_ the safe steps. It is more complete as it allows multiple
  5093     instantiations of unknowns (e.g. with slow_tac).
  5094 
  5095 *** Simplifier ***
  5096 
  5097 * added interface for simplification procedures (functions that
  5098 produce *proven* rewrite rules on the fly, depending on current
  5099 redex);
  5100 
  5101 * ordering on terms as parameter (used for ordered rewriting);
  5102 
  5103 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5104 
  5105 * the solver is now split into a safe and an unsafe part.
  5106 This should be invisible for the normal user, except that the
  5107 functions setsolver and addsolver have been renamed to setSolver and
  5108 addSolver; added safe_asm_full_simp_tac;
  5109 
  5110 
  5111 *** HOL ***
  5112 
  5113 * a generic induction tactic `induct_tac' which works for all datatypes and
  5114 also for type `nat';
  5115 
  5116 * a generic case distinction tactic `exhaust_tac' which works for all
  5117 datatypes and also for type `nat';
  5118 
  5119 * each datatype comes with a function `size';
  5120 
  5121 * patterns in case expressions allow tuple patterns as arguments to
  5122 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5123 
  5124 * primrec now also works with type nat;
  5125 
  5126 * recdef: a new declaration form, allows general recursive functions to be
  5127 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5128 
  5129 * the constant for negation has been renamed from "not" to "Not" to
  5130 harmonize with FOL, ZF, LK, etc.;
  5131 
  5132 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5133 infinite lists;
  5134 
  5135 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5136 
  5137 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5138 problems in commutative rings, using axiomatic type classes for + and *;
  5139 
  5140 * more examples in HOL/MiniML and HOL/Auth;
  5141 
  5142 * more default rewrite rules for quantifiers, union/intersection;
  5143 
  5144 * a new constant `arbitrary == @x.False';
  5145 
  5146 * HOLCF/IOA replaces old HOL/IOA;
  5147 
  5148 * HOLCF changes: derived all rules and arities
  5149   + axiomatic type classes instead of classes
  5150   + typedef instead of faking type definitions
  5151   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5152   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5153   + eliminated the types void, one, tr
  5154   + use unit lift and bool lift (with translations) instead of one and tr
  5155   + eliminated blift from Lift3.thy (use Def instead of blift)
  5156   all eliminated rules are derived as theorems --> no visible changes ;
  5157 
  5158 
  5159 *** ZF ***
  5160 
  5161 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5162 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5163 as ZF_cs addSIs [equalityI];
  5164 
  5165 
  5166 
  5167 New in Isabelle94-7 (November 96)
  5168 ---------------------------------
  5169 
  5170 * allowing negative levels (as offsets) in prlev and choplev;
  5171 
  5172 * super-linear speedup for large simplifications;
  5173 
  5174 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5175 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5176 FAIL); can suppress it using the command Delsimps (ex_simps @
  5177 all_simps); De Morgan laws are also now included, by default;
  5178 
  5179 * improved printing of ==>  :  ~:
  5180 
  5181 * new object-logic "Sequents" adds linear logic, while replacing LK
  5182 and Modal (thanks to Sara Kalvala);
  5183 
  5184 * HOL/Auth: correctness proofs for authentication protocols;
  5185 
  5186 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5187 examples on HOL/Auth);
  5188 
  5189 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5190 the rewriter and classical reasoner simultaneously;
  5191 
  5192 * function uresult no longer returns theorems in "standard" format;
  5193 regain previous version by: val uresult = standard o uresult;
  5194 
  5195 
  5196 
  5197 New in Isabelle94-6
  5198 -------------------
  5199 
  5200 * oracles -- these establish an interface between Isabelle and trusted
  5201 external reasoners, which may deliver results as theorems;
  5202 
  5203 * proof objects (in particular record all uses of oracles);
  5204 
  5205 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5206 
  5207 * "constdefs" section in theory files;
  5208 
  5209 * "primrec" section (HOL) no longer requires names;
  5210 
  5211 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5212 
  5213 
  5214 
  5215 New in Isabelle94-5
  5216 -------------------
  5217 
  5218 * reduced space requirements;
  5219 
  5220 * automatic HTML generation from theories;
  5221 
  5222 * theory files no longer require "..." (quotes) around most types;
  5223 
  5224 * new examples, including two proofs of the Church-Rosser theorem;
  5225 
  5226 * non-curried (1994) version of HOL is no longer distributed;
  5227 
  5228 
  5229 
  5230 New in Isabelle94-4
  5231 -------------------
  5232 
  5233 * greatly reduced space requirements;
  5234 
  5235 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5236 
  5237 * searchable theorem database (see the section "Retrieving theorems" on
  5238 page 8 of the Reference Manual);
  5239 
  5240 * new examples, including Grabczewski's monumental case study of the
  5241 Axiom of Choice;
  5242 
  5243 * The previous version of HOL renamed to Old_HOL;
  5244 
  5245 * The new version of HOL (previously called CHOL) uses a curried syntax
  5246 for functions.  Application looks like f a b instead of f(a,b);
  5247 
  5248 * Mutually recursive inductive definitions finally work in HOL;
  5249 
  5250 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5251 translates to the operator "split";
  5252 
  5253 
  5254 
  5255 New in Isabelle94-3
  5256 -------------------
  5257 
  5258 * new infix operator, addss, allowing the classical reasoner to
  5259 perform simplification at each step of its search.  Example:
  5260         fast_tac (cs addss ss)
  5261 
  5262 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5263 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5264 look like (a,b) instead of <a,b>;
  5265 
  5266 * PLEASE NOTE: CHOL will eventually replace HOL!
  5267 
  5268 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5269 It translates to the operator "split".  A new theory of integers is available;
  5270 
  5271 * In ZF, integer numerals now denote two's-complement binary integers.
  5272 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5273 
  5274 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5275 of the Axiom of Choice;
  5276 
  5277 
  5278 
  5279 New in Isabelle94-2
  5280 -------------------
  5281 
  5282 * Significantly faster resolution;
  5283 
  5284 * the different sections in a .thy file can now be mixed and repeated
  5285 freely;
  5286 
  5287 * Database of theorems for FOL, HOL and ZF.  New
  5288 commands including qed, qed_goal and bind_thm store theorems in the database.
  5289 
  5290 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5291 a given theory (thms_of), or find out what theory a theorem was proved in
  5292 (theory_of_thm);
  5293 
  5294 * Bugs fixed in the inductive definition and datatype packages;
  5295 
  5296 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5297 and HOL_dup_cs obsolete;
  5298 
  5299 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5300 have been removed;
  5301 
  5302 * Simpler definition of function space in ZF;
  5303 
  5304 * new results about cardinal and ordinal arithmetic in ZF;
  5305 
  5306 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5307 types;
  5308 
  5309 :mode=text:wrap=hard:maxLineLen=72:
  5310 
  5311 $Id$