NEWS
author haftmann
Thu Mar 27 19:04:39 2008 +0100 (2008-03-27)
changeset 26445 17223cf843d8
parent 26434 d004b791218e
child 26479 3a2efce3e992
permissions -rw-r--r--
explicit case names for rule list_induct2
     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 theory ProtoPure.  Potential INCOMPATIBILITY.
    33 
    34 * Command 'setup': discontinued implicit version.
    35 
    36 * Instantiation target allows for simultaneous specification of class
    37 instance operations together with an instantiation proof.
    38 Type-checking phase allows to refer to class operations uniformly.
    39 See HOL/Complex/Complex.thy for an Isar example and
    40 HOL/Library/Eval.thy for an ML example.
    41 
    42 * Indexing of literal facts: be more serious about including only
    43 facts from the visible specification/proof context, but not the
    44 background context (locale etc.).  Affects `prop` notation and method
    45 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
    46 situations.
    47 
    48 
    49 *** HOL ***
    50 
    51 * Class finite no longer treats UNIV as class parameter.  Use class enum from
    52 theory Library/Enum instead to achieve a similar effect.  INCOMPATIBILITY.
    53 
    54 * Theory List: rule list_induct2 now has explicitly named cases "Nil" and "Cons".
    55 INCOMPATIBILITY.
    56 
    57 * HOL (and FOL): renamed variables in rules imp_elim and swap.
    58 Potential INCOMPATIBILITY.
    59 
    60 * Theory Product_Type: duplicated lemmas split_Pair_apply and injective_fst_snd
    61 removed, use split_eta and prod_eqI instead.  Renamed upd_fst to apfst and upd_snd
    62 to apsnd.  INCOMPATIBILITY.
    63 
    64 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
    65 the same name in theory Orderings:
    66 
    67   less_trans
    68   less_linear
    69   le_imp_less_or_eq
    70   le_less_trans
    71   less_le_trans
    72   less_not_sym
    73   less_asym
    74 
    75 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
    76 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
    77 and different variable names.
    78 
    79 * Library/Option_ord.thy: Canonical order on option type.
    80 
    81 * Library/RBT.thy: New theory of red-black trees, an efficient
    82 implementation of finite maps.
    83 
    84 * Library/Countable.thy: Type class for countable types.
    85 
    86 * Theory Int: The representation of numerals has changed.  The infix
    87 operator BIT and the bit datatype with constructors B0 and B1 have
    88 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
    89 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
    90 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
    91 accordingly.
    92 
    93 * Theory Nat: definition of <= and < on natural numbers no longer
    94 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
    95 le_def and less_def have disappeared.  Consider lemmas not_less
    96 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
    97 
    98 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
    99 (whose purpose mainly is for various fold_set functionals) have been
   100 abandoned in favour of the existing algebraic classes
   101 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
   102 lower_semilattice (resp. upper_semilattice) and linorder.
   103 INCOMPATIBILITY.
   104 
   105 * Theory Transitive_Closure: induct and cases rules now declare proper
   106 case_names ("base" and "step").  INCOMPATIBILITY.
   107 
   108 * Theorem Inductive.lfp_ordinal_induct generalized to complete
   109 lattices.  The form set-specific version is available as
   110 Inductive.lfp_ordinal_induct_set.
   111 
   112 * Theorems "power.simps" renamed to "power_int.simps".
   113 
   114 * Class semiring_div provides basic abstract properties of semirings
   115 with division and modulo operations.  Subsumes former class dvd_mod.
   116 
   117 * Merged theories IntDef, Numeral and IntArith into unified theory
   118 Int.  INCOMPATIBILITY.
   119 
   120 * Theory Library/Code_Index: type "index" now represents natural
   121 numbers rather than integers.  INCOMPATIBILITY.
   122 
   123 * New class "uminus" with operation "uminus" (split of from class
   124 "minus" which now only has operation "minus", binary).
   125 INCOMPATIBILITY.
   126 
   127 * New primrec package.  Specification syntax conforms in style to
   128 definition/function/....  No separate induction rule is provided.  The
   129 "primrec" command distinguishes old-style and new-style specifications
   130 by syntax.  The former primrec package is now named OldPrimrecPackage.
   131 When adjusting theories, beware: constants stemming from new-style
   132 primrec specifications have authentic syntax.
   133 
   134 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
   135 
   136 * Library/ListVector: new theory of arithmetic vector operations.
   137 
   138 * Constants "card", "internal_split", "option_map" now with authentic
   139 syntax.  INCOMPATIBILITY.
   140 
   141 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
   142 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
   143 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
   144 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
   145 Sup_set_def, le_def, less_def, option_map_def now with object
   146 equality.  INCOMPATIBILITY.
   147 
   148 * Method "induction_scheme" derives user-specified induction rules
   149 from wellfounded induction and completeness of patterns. This factors
   150 out some operations that are done internally by the function package
   151 and makes them available separately. See "HOL/ex/Induction_Scheme.thy"
   152 for examples,
   153 
   154 * Records. Removed K_record, and replaced it by pure lambda term
   155 %x. c. The simplifier setup is now more robust against eta expansion.
   156 INCOMPATIBILITY: in cases explicitly referring to K_record.
   157 
   158 * Metis prover is now an order of magnitude faster, and also works
   159 with multithreading.
   160 
   161 * Sledgehammer no longer produces structured proofs by default. To enable, 
   162 declare [[sledgehammer_full = true]]. Attributes reconstruction_modulus,  
   163 reconstruction_sorts renamed sledgehammer_modulus, sledgehammer_sorts. 
   164 INCOMPATIBILITY.
   165 
   166 *** ZF ***
   167 
   168 * Renamed theories:
   169 
   170   Datatype.thy  -> Datatype_ZF.thy
   171   Inductive.thy -> Inductive_ZF.thy
   172   Int.thy       -> Int_ZF.thy
   173   IntDiv.thy    -> IntDiv_ZF.thy
   174   Nat.thy       -> Nat_ZF.thy
   175   List.thy      -> List_ZF.thy
   176   Main.thy      -> Main_ZF.thy
   177 
   178  This is to allow to load both ZF and HOL in the same session.
   179 
   180  INCOMPATIBILITY: ZF theories that import individual theories below
   181  Main might need to be adapted. For compatibility, a new 
   182  "theory Main imports Main_ZF begin end" is provided, so if you just
   183  imported "Main", no changes are needed.
   184 
   185 
   186 *** ML ***
   187 
   188 * Functor NamedThmsFun: data is available to the user as dynamic fact
   189 (of the same name).
   190 
   191 * Removed obsolete "use_legacy_bindings" function.  INCOMPATIBILITY.
   192 
   193 * ML within Isar: antiquotation @{const name} or @{const
   194 name(typargs)} produces statically-checked Const term.
   195 
   196 * The ``print mode'' is now a thread-local value derived from a global
   197 template (the former print_mode reference), thus access becomes
   198 non-critical.  The global print_mode reference is for session
   199 management only; user-code should use print_mode_value,
   200 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
   201 
   202 * system/system_out provides a robust way to invoke external shell
   203 commands, with propagation of interrupts (after Poly/ML 5.2).  Do not
   204 use OS.Process.system etc. directly.
   205 
   206 
   207 *** System ***
   208 
   209 * System: removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the
   210 documented way of changing the user's settings is via
   211 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
   212 script.
   213 
   214 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
   215 in accordance with Proof General 3.7, which prefers GNU emacs.
   216 
   217 * Multithreading.max_threads := 0 refers to the number of actual CPU
   218 cores of the underlying machine, which is a good starting point for
   219 optimal performance tuning.  The corresponding usedir option -M allows
   220 "max" as an alias for "0".  WARNING: does not work on certain versions
   221 of Mac OS (with Poly/ML 5.1).
   222 
   223 * isatool tty runs Isabelle process with plain tty interaction;
   224 optional line editor may be specified via ISABELLE_LINE_EDITOR
   225 setting, the default settings attempt to locate "ledit" and "rlwrap".
   226 
   227 * isatool browser now works with Cygwin as well, using general
   228 "javapath" function defined in Isabelle process environment.
   229 
   230 * isabelle-process: non-ML sessions are run with "nice", to prevent
   231 Isabelle from flooding interactive front-ends (notably ProofGeneral /
   232 XEmacs).
   233 
   234 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   235 provides general wrapper for managing an Isabelle process in a robust
   236 fashion, with ``cooked'' output from stdin/stderr.
   237 
   238 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   239 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   240 
   241 
   242 
   243 New in Isabelle2007 (November 2007)
   244 -----------------------------------
   245 
   246 *** General ***
   247 
   248 * More uniform information about legacy features, notably a
   249 warning/error of "Legacy feature: ...", depending on the state of the
   250 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   251 legacy features will disappear eventually.
   252 
   253 * Theory syntax: the header format ``theory A = B + C:'' has been
   254 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   255 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   256 
   257 * Theory syntax: the old non-Isar theory file format has been
   258 discontinued altogether.  Note that ML proof scripts may still be used
   259 with Isar theories; migration is usually quite simple with the ML
   260 function use_legacy_bindings.  INCOMPATIBILITY.
   261 
   262 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   263 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   264 quotes.
   265 
   266 * Theory loader: be more serious about observing the static theory
   267 header specifications (including optional directories), but not the
   268 accidental file locations of previously successful loads.  The strict
   269 update policy of former update_thy is now already performed by
   270 use_thy, so the former has been removed; use_thys updates several
   271 theories simultaneously, just as 'imports' within a theory header
   272 specification, but without merging the results.  Potential
   273 INCOMPATIBILITY: may need to refine theory headers and commands
   274 ROOT.ML which depend on load order.
   275 
   276 * Theory loader: optional support for content-based file
   277 identification, instead of the traditional scheme of full physical
   278 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   279 (cf. the system manual).  The new scheme allows to work with
   280 non-finished theories in persistent session images, such that source
   281 files may be moved later on without requiring reloads.
   282 
   283 * Theory loader: old-style ML proof scripts being *attached* to a thy
   284 file (with the same base name as the theory) are considered a legacy
   285 feature, which will disappear eventually. Even now, the theory loader
   286 no longer maintains dependencies on such files.
   287 
   288 * Syntax: the scope for resolving ambiguities via type-inference is
   289 now limited to individual terms, instead of whole simultaneous
   290 specifications as before. This greatly reduces the complexity of the
   291 syntax module and improves flexibility by separating parsing and
   292 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
   293 'fixes' etc.) are required in rare situations.
   294 
   295 * Syntax: constants introduced by new-style packages ('definition',
   296 'abbreviation' etc.) are passed through the syntax module in
   297 ``authentic mode''. This means that associated mixfix annotations
   298 really stick to such constants, independently of potential name space
   299 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
   300 trees are represented slightly differently, may need to adapt syntax
   301 translations accordingly. Use CONST marker in 'translations' and
   302 @{const_syntax} antiquotation in 'parse_translation' etc.
   303 
   304 * Legacy goal package: reduced interface to the bare minimum required
   305 to keep existing proof scripts running.  Most other user-level
   306 functions are now part of the OldGoals structure, which is *not* open
   307 by default (consider isatool expandshort before open OldGoals).
   308 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   309 these tend to cause confusion about the actual goal (!) context being
   310 used here, which is not necessarily the same as the_context().
   311 
   312 * Command 'find_theorems': supports "*" wild-card in "name:"
   313 criterion; "with_dups" option.  Certain ProofGeneral versions might
   314 support a specific search form (see ProofGeneral/CHANGES).
   315 
   316 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   317 by default, which means that "prems" (and also "fixed variables") are
   318 suppressed from proof state output.  Note that the ProofGeneral
   319 settings mechanism allows to change and save options persistently, but
   320 older versions of Isabelle will fail to start up if a negative prems
   321 limit is imposed.
   322 
   323 * Local theory targets may be specified by non-nested blocks of
   324 ``context/locale/class ... begin'' followed by ``end''.  The body may
   325 contain definitions, theorems etc., including any derived mechanism
   326 that has been implemented on top of these primitives.  This concept
   327 generalizes the existing ``theorem (in ...)'' towards more versatility
   328 and scalability.
   329 
   330 * Proof General interface: proper undo of final 'end' command;
   331 discontinued Isabelle/classic mode (ML proof scripts).
   332 
   333 
   334 *** Document preparation ***
   335 
   336 * Added antiquotation @{theory name} which prints the given name,
   337 after checking that it refers to a valid ancestor theory in the
   338 current context.
   339 
   340 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   341 check the given source text as ML type/structure, printing verbatim.
   342 
   343 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   344 "c args == rhs" given in the current context.  (Any number of
   345 arguments may be given on the LHS.)
   346 
   347 
   348 *** Pure ***
   349 
   350 * The 'class' package offers a combination of axclass and locale to
   351 achieve Haskell-like type classes in Isabelle.  Definitions and
   352 theorems within a class context produce both relative results (with
   353 implicit parameters according to the locale context), and polymorphic
   354 constants with qualified polymorphism (according to the class
   355 context).  Within the body context of a 'class' target, a separate
   356 syntax layer ("user space type system") takes care of converting
   357 between global polymorphic consts and internal locale representation.
   358 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   359 "isatool doc classes" provides a tutorial.
   360 
   361 * Generic code generator framework allows to generate executable
   362 code for ML and Haskell (including Isabelle classes).  A short usage
   363 sketch:
   364 
   365     internal compilation:
   366         export_code <list of constants (term syntax)> in SML
   367     writing SML code to a file:
   368         export_code <list of constants (term syntax)> in SML <filename>
   369     writing OCaml code to a file:
   370         export_code <list of constants (term syntax)> in OCaml <filename>
   371     writing Haskell code to a bunch of files:
   372         export_code <list of constants (term syntax)> in Haskell <filename>
   373 
   374     evaluating closed propositions to True/False using code generation:
   375         method ``eval''
   376 
   377 Reasonable default setup of framework in HOL.
   378 
   379 Theorem attributs for selecting and transforming function equations theorems:
   380 
   381     [code fun]:        select a theorem as function equation for a specific constant
   382     [code fun del]:    deselect a theorem as function equation for a specific constant
   383     [code inline]:     select an equation theorem for unfolding (inlining) in place
   384     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   385 
   386 User-defined serializations (target in {SML, OCaml, Haskell}):
   387 
   388     code_const <and-list of constants (term syntax)>
   389       {(target) <and-list of const target syntax>}+
   390 
   391     code_type <and-list of type constructors>
   392       {(target) <and-list of type target syntax>}+
   393 
   394     code_instance <and-list of instances>
   395       {(target)}+
   396         where instance ::= <type constructor> :: <class>
   397 
   398     code_class <and_list of classes>
   399       {(target) <and-list of class target syntax>}+
   400         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   401 
   402 code_instance and code_class only are effective to target Haskell.
   403 
   404 For example usage see src/HOL/ex/Codegenerator.thy and
   405 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   406 generation from Isabelle/HOL theories is available via "isatool doc
   407 codegen".
   408 
   409 * Code generator: consts in 'consts_code' Isar commands are now
   410 referred to by usual term syntax (including optional type
   411 annotations).
   412 
   413 * Command 'no_translations' removes translation rules from theory
   414 syntax.
   415 
   416 * Overloaded definitions are now actually checked for acyclic
   417 dependencies.  The overloading scheme is slightly more general than
   418 that of Haskell98, although Isabelle does not demand an exact
   419 correspondence to type class and instance declarations.
   420 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   421 exotic versions of overloading -- at the discretion of the user!
   422 
   423 Polymorphic constants are represented via type arguments, i.e. the
   424 instantiation that matches an instance against the most general
   425 declaration given in the signature.  For example, with the declaration
   426 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   427 as c(nat).  Overloading is essentially simultaneous structural
   428 recursion over such type arguments.  Incomplete specification patterns
   429 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   430 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   431 Command 'print_theory' outputs the normalized system of recursive
   432 equations, see section "definitions".
   433 
   434 * Configuration options are maintained within the theory or proof
   435 context (with name and type bool/int/string), providing a very simple
   436 interface to a poor-man's version of general context data.  Tools may
   437 declare options in ML (e.g. using Attrib.config_int) and then refer to
   438 these values using Config.get etc.  Users may change options via an
   439 associated attribute of the same name.  This form of context
   440 declaration works particularly well with commands 'declare' or
   441 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   442 very easy to avoid global references, which would not observe Isar
   443 toplevel undo/redo and fail to work with multithreading.
   444 
   445 Various global ML references of Pure and HOL have been turned into
   446 configuration options:
   447 
   448   Unify.search_bound		unify_search_bound
   449   Unify.trace_bound		unify_trace_bound
   450   Unify.trace_simp		unify_trace_simp
   451   Unify.trace_types		unify_trace_types
   452   Simplifier.simp_depth_limit	simp_depth_limit
   453   Blast.depth_limit		blast_depth_limit
   454   DatatypeProp.dtK		datatype_distinctness_limit
   455   fast_arith_neq_limit  	fast_arith_neq_limit
   456   fast_arith_split_limit	fast_arith_split_limit
   457 
   458 * Named collections of theorems may be easily installed as context
   459 data using the functor NamedThmsFun (see also
   460 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   461 attributes; there is also a toplevel print command.  This facility is
   462 just a common case of general context data, which is the preferred way
   463 for anything more complex than just a list of facts in canonical
   464 order.
   465 
   466 * Isar: command 'declaration' augments a local theory by generic
   467 declaration functions written in ML.  This enables arbitrary content
   468 being added to the context, depending on a morphism that tells the
   469 difference of the original declaration context wrt. the application
   470 context encountered later on.
   471 
   472 * Isar: proper interfaces for simplification procedures.  Command
   473 'simproc_setup' declares named simprocs (with match patterns, and body
   474 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   475 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   476 
   477 * Isar: an extra pair of brackets around attribute declarations
   478 abbreviates a theorem reference involving an internal dummy fact,
   479 which will be ignored later --- only the effect of the attribute on
   480 the background context will persist.  This form of in-place
   481 declarations is particularly useful with commands like 'declare' and
   482 'using', for example ``have A using [[simproc a]] by simp''.
   483 
   484 * Isar: method "assumption" (and implicit closing of subproofs) now
   485 takes simple non-atomic goal assumptions into account: after applying
   486 an assumption as a rule the resulting subgoals are solved by atomic
   487 assumption steps.  This is particularly useful to finish 'obtain'
   488 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   489 without referring to the original premise "!!x. P x ==> thesis" in the
   490 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   491 more permissive.
   492 
   493 * Isar: implicit use of prems from the Isar proof context is
   494 considered a legacy feature.  Common applications like ``have A .''
   495 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   496 referencing facts explicitly here improves readability and
   497 maintainability of proof texts.
   498 
   499 * Isar: improper proof element 'guess' is like 'obtain', but derives
   500 the obtained context from the course of reasoning!  For example:
   501 
   502   assume "EX x y. A x & B y"   -- "any previous fact"
   503   then guess x and y by clarify
   504 
   505 This technique is potentially adventurous, depending on the facts and
   506 proof tools being involved here.
   507 
   508 * Isar: known facts from the proof context may be specified as literal
   509 propositions, using ASCII back-quote syntax.  This works wherever
   510 named facts used to be allowed so far, in proof commands, proof
   511 methods, attributes etc.  Literal facts are retrieved from the context
   512 according to unification of type and term parameters.  For example,
   513 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   514 theorems in the current context, then these are valid literal facts:
   515 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   516 
   517 There is also a proof method "fact" which does the same composition
   518 for explicit goal states, e.g. the following proof texts coincide with
   519 certain special cases of literal facts:
   520 
   521   have "A" by fact                 ==  note `A`
   522   have "A ==> B" by fact           ==  note `A ==> B`
   523   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   524   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   525 
   526 * Isar: ":" (colon) is no longer a symbolic identifier character in
   527 outer syntax.  Thus symbolic identifiers may be used without
   528 additional white space in declarations like this: ``assume *: A''.
   529 
   530 * Isar: 'print_facts' prints all local facts of the current context,
   531 both named and unnamed ones.
   532 
   533 * Isar: 'def' now admits simultaneous definitions, e.g.:
   534 
   535   def x == "t" and y == "u"
   536 
   537 * Isar: added command 'unfolding', which is structurally similar to
   538 'using', but affects both the goal state and facts by unfolding given
   539 rewrite rules.  Thus many occurrences of the 'unfold' method or
   540 'unfolded' attribute may be replaced by first-class proof text.
   541 
   542 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   543 and command 'unfolding' now all support object-level equalities
   544 (potentially conditional).  The underlying notion of rewrite rule is
   545 analogous to the 'rule_format' attribute, but *not* that of the
   546 Simplifier (which is usually more generous).
   547 
   548 * Isar: the new attribute [rotated n] (default n = 1) rotates the
   549 premises of a theorem by n. Useful in conjunction with drule.
   550 
   551 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   552 method expression within a sandbox consisting of the first N
   553 sub-goals, which need to exist.  For example, ``simp_all [3]''
   554 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   555 simplifies all new goals that emerge from applying rule foo to the
   556 originally first one.
   557 
   558 * Isar: schematic goals are no longer restricted to higher-order
   559 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   560 expected.
   561 
   562 * Isar: the conclusion of a long theorem statement is now either
   563 'shows' (a simultaneous conjunction, as before), or 'obtains'
   564 (essentially a disjunction of cases with local parameters and
   565 assumptions).  The latter allows to express general elimination rules
   566 adequately; in this notation common elimination rules look like this:
   567 
   568   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   569     assumes "EX x. P x"
   570     obtains x where "P x"
   571 
   572   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   573     assumes "A & B"
   574     obtains A and B
   575 
   576   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   577     assumes "A | B"
   578     obtains
   579       A
   580     | B
   581 
   582 The subsequent classical rules even refer to the formal "thesis"
   583 explicitly:
   584 
   585   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   586     obtains "~ thesis"
   587 
   588   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   589     obtains "thesis ==> something"
   590 
   591 The actual proof of an 'obtains' statement is analogous to that of the
   592 Isar proof element 'obtain', only that there may be several cases.
   593 Optional case names may be specified in parentheses; these will be
   594 available both in the present proof and as annotations in the
   595 resulting rule, for later use with the 'cases' method (cf. attribute
   596 case_names).
   597 
   598 * Isar: the assumptions of a long theorem statement are available as
   599 "assms" fact in the proof context.  This is more appropriate than the
   600 (historical) "prems", which refers to all assumptions of the current
   601 context, including those from the target locale, proof body etc.
   602 
   603 * Isar: 'print_statement' prints theorems from the current theory or
   604 proof context in long statement form, according to the syntax of a
   605 top-level lemma.
   606 
   607 * Isar: 'obtain' takes an optional case name for the local context
   608 introduction rule (default "that").
   609 
   610 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   611 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   612 to occur.
   613 
   614 * Pure: syntax "CONST name" produces a fully internalized constant
   615 according to the current context.  This is particularly useful for
   616 syntax translations that should refer to internal constant
   617 representations independently of name spaces.
   618 
   619 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   620 instead of "FOO ". This allows multiple binder declarations to coexist
   621 in the same context.  INCOMPATIBILITY.
   622 
   623 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   624 primitive that also works in a locale context (both for constants and
   625 fixed variables). Type declaration and internal syntactic representation
   626 of given constants retrieved from the context. Likewise, the
   627 'no_notation' command allows to remove given syntax annotations from the
   628 current context.
   629 
   630 * Isar/locales: new derived specification elements 'axiomatization',
   631 'definition', 'abbreviation', which support type-inference, admit
   632 object-level specifications (equality, equivalence).  See also the
   633 isar-ref manual.  Examples:
   634 
   635   axiomatization
   636     eq  (infix "===" 50) where
   637     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   638 
   639   definition "f x y = x + y + 1"
   640   definition g where "g x = f x x"
   641 
   642   abbreviation
   643     neq  (infix "=!=" 50) where
   644     "x =!= y == ~ (x === y)"
   645 
   646 These specifications may be also used in a locale context.  Then the
   647 constants being introduced depend on certain fixed parameters, and the
   648 constant name is qualified by the locale base name.  An internal
   649 abbreviation takes care for convenient input and output, making the
   650 parameters implicit and using the original short name.  See also
   651 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   652 entities from a monomorphic theory.
   653 
   654 Presently, abbreviations are only available 'in' a target locale, but
   655 not inherited by general import expressions.  Also note that
   656 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   657 'translations' in common applications.  The "no_abbrevs" print mode
   658 prevents folding of abbreviations in term output.
   659 
   660 Concrete syntax is attached to specified constants in internal form,
   661 independently of name spaces.  The parse tree representation is
   662 slightly different -- use 'notation' instead of raw 'syntax', and
   663 'translations' with explicit "CONST" markup to accommodate this.
   664 
   665 * Pure/Isar: unified syntax for new-style specification mechanisms
   666 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
   667 full type inference and dummy patterns ("_").  For example:
   668 
   669   definition "K x _ = x"
   670 
   671   inductive conj for A B
   672   where "A ==> B ==> conj A B"
   673 
   674 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   675 the current context.  Print mode "no_abbrevs" prevents inversion of
   676 abbreviations on output.
   677 
   678 * Isar/locales: improved parameter handling: use of locales "var" and
   679 "struct" no longer necessary; - parameter renamings are no longer
   680 required to be injective.  For example, this allows to define
   681 endomorphisms as locale endom = homom mult mult h.
   682 
   683 * Isar/locales: changed the way locales with predicates are defined.
   684 Instead of accumulating the specification, the imported expression is
   685 now an interpretation.  INCOMPATIBILITY: different normal form of
   686 locale expressions.  In particular, in interpretations of locales with
   687 predicates, goals repesenting already interpreted fragments are not
   688 removed automatically.  Use methods `intro_locales' and
   689 `unfold_locales'; see below.
   690 
   691 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   692 provide backward reasoning on locales predicates.  The methods are
   693 aware of interpretations and discharge corresponding goals.
   694 `intro_locales' is less aggressive then `unfold_locales' and does not
   695 unfold predicates to assumptions.
   696 
   697 * Isar/locales: the order in which locale fragments are accumulated
   698 has changed.  This enables to override declarations from fragments due
   699 to interpretations -- for example, unwanted simp rules.
   700 
   701 * Isar/locales: interpretation in theories and proof contexts has been
   702 extended.  One may now specify (and prove) equations, which are
   703 unfolded in interpreted theorems.  This is useful for replacing
   704 defined concepts (constants depending on locale parameters) by
   705 concepts already existing in the target context.  Example:
   706 
   707   interpretation partial_order ["op <= :: [int, int] => bool"]
   708     where "partial_order.less (op <=) (x::int) y = (x < y)"
   709 
   710 Typically, the constant `partial_order.less' is created by a
   711 definition specification element in the context of locale
   712 partial_order.
   713 
   714 * Method "induct": improved internal context management to support
   715 local fixes and defines on-the-fly. Thus explicit meta-level
   716 connectives !!  and ==> are rarely required anymore in inductive goals
   717 (using object-logic connectives for this purpose has been long
   718 obsolete anyway). Common proof patterns are explained in
   719 src/HOL/Induct/Common_Patterns.thy, see also
   720 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
   721 examples.
   722 
   723 * Method "induct": improved handling of simultaneous goals. Instead of
   724 introducing object-level conjunction, the statement is now split into
   725 several conclusions, while the corresponding symbolic cases are nested
   726 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
   727 see src/HOL/Induct/Common_Patterns.thy, for example.
   728 
   729 * Method "induct": mutual induction rules are now specified as a list
   730 of rule sharing the same induction cases. HOL packages usually provide
   731 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
   732 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
   733 mutual induction rules differently, i.e. like this:
   734 
   735   (induct rule: foo_bar.inducts)
   736   (induct set: foo bar)
   737   (induct pred: foo bar)
   738   (induct type: foo bar)
   739 
   740 The ML function ProjectRule.projections turns old-style rules into the
   741 new format.
   742 
   743 * Method "coinduct": dual of induction, see
   744 src/HOL/Library/Coinductive_List.thy for various examples.
   745 
   746 * Method "cases", "induct", "coinduct": the ``(open)'' option is
   747 considered a legacy feature.
   748 
   749 * Attribute "symmetric" produces result with standardized schematic
   750 variables (index 0).  Potential INCOMPATIBILITY.
   751 
   752 * Simplifier: by default the simplifier trace only shows top level
   753 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   754 default. Thus there is less danger of being flooded by the trace. The
   755 trace indicates where parts have been suppressed.
   756   
   757 * Provers/classical: removed obsolete classical version of elim_format
   758 attribute; classical elim/dest rules are now treated uniformly when
   759 manipulating the claset.
   760 
   761 * Provers/classical: stricter checks to ensure that supplied intro,
   762 dest and elim rules are well-formed; dest and elim rules must have at
   763 least one premise.
   764 
   765 * Provers/classical: attributes dest/elim/intro take an optional
   766 weight argument for the rule (just as the Pure versions).  Weights are
   767 ignored by automated tools, but determine the search order of single
   768 rule steps.
   769 
   770 * Syntax: input syntax now supports dummy variable binding "%_. b",
   771 where the body does not mention the bound variable.  Note that dummy
   772 patterns implicitly depend on their context of bounds, which makes
   773 "{_. _}" match any set comprehension as expected.  Potential
   774 INCOMPATIBILITY -- parse translations need to cope with syntactic
   775 constant "_idtdummy" in the binding position.
   776 
   777 * Syntax: removed obsolete syntactic constant "_K" and its associated
   778 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   779 for example "A -> B" => "Pi A (%_. B)".
   780 
   781 * Pure: 'class_deps' command visualizes the subclass relation, using
   782 the graph browser tool.
   783 
   784 * Pure: 'print_theory' now suppresses certain internal declarations by
   785 default; use '!' option for full details.
   786 
   787 
   788 *** HOL ***
   789 
   790 * Method "metis" proves goals by applying the Metis general-purpose
   791 resolution prover (see also http://gilith.com/software/metis/).
   792 Examples are in the directory MetisExamples.  WARNING: the
   793 Isabelle/HOL-Metis integration does not yet work properly with
   794 multi-threading.
   795   
   796 * Command 'sledgehammer' invokes external automatic theorem provers as
   797 background processes.  It generates calls to the "metis" method if
   798 successful. These can be pasted into the proof.  Users do not have to
   799 wait for the automatic provers to return.  WARNING: does not really
   800 work with multi-threading.
   801 
   802 * New "auto_quickcheck" feature tests outermost goal statements for
   803 potential counter-examples.  Controlled by ML references
   804 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
   805 5000 milliseconds).  Fails silently if statements is outside of
   806 executable fragment, or any other codgenerator problem occurs.
   807 
   808 * New constant "undefined" with axiom "undefined x = undefined".
   809 
   810 * Added class "HOL.eq", allowing for code generation with polymorphic
   811 equality.
   812 
   813 * Some renaming of class constants due to canonical name prefixing in
   814 the new 'class' package:
   815 
   816     HOL.abs ~> HOL.abs_class.abs
   817     HOL.divide ~> HOL.divide_class.divide
   818     0 ~> HOL.zero_class.zero
   819     1 ~> HOL.one_class.one
   820     op + ~> HOL.plus_class.plus
   821     op - ~> HOL.minus_class.minus
   822     uminus ~> HOL.minus_class.uminus
   823     op * ~> HOL.times_class.times
   824     op < ~> HOL.ord_class.less
   825     op <= > HOL.ord_class.less_eq
   826     Nat.power ~> Power.power_class.power
   827     Nat.size ~> Nat.size_class.size
   828     Numeral.number_of ~> Numeral.number_class.number_of
   829     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
   830     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
   831     Orderings.min ~> Orderings.ord_class.min
   832     Orderings.max ~> Orderings.ord_class.max
   833     Divides.op div ~> Divides.div_class.div
   834     Divides.op mod ~> Divides.div_class.mod
   835     Divides.op dvd ~> Divides.div_class.dvd
   836 
   837 INCOMPATIBILITY.  Adaptions may be required in the following cases:
   838 
   839 a) User-defined constants using any of the names "plus", "minus",
   840 "times", "less" or "less_eq". The standard syntax translations for
   841 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
   842 names.
   843 
   844 b) Variables named "plus", "minus", "times", "less", "less_eq"
   845 INCOMPATIBILITY: use more specific names.
   846 
   847 c) Permutative equations (e.g. "a + b = b + a")
   848 Since the change of names also changes the order of terms, permutative
   849 rewrite rules may get applied in a different order. Experience shows
   850 that this is rarely the case (only two adaptions in the whole Isabelle
   851 distribution).  INCOMPATIBILITY: rewrite proofs
   852 
   853 d) ML code directly refering to constant names
   854 This in general only affects hand-written proof tactics, simprocs and
   855 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
   856 Consider using @{const_name} antiquotation.
   857 
   858 * New class "default" with associated constant "default".
   859 
   860 * Function "sgn" is now overloaded and available on int, real, complex
   861 (and other numeric types), using class "sgn".  Two possible defs of
   862 sgn are given as equational assumptions in the classes sgn_if and
   863 sgn_div_norm; ordered_idom now also inherits from sgn_if.
   864 INCOMPATIBILITY.
   865 
   866 * Locale "partial_order" now unified with class "order" (cf. theory
   867 Orderings), added parameter "less".  INCOMPATIBILITY.
   868 
   869 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
   870 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
   871 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
   872 
   873 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
   874 changed order of proof goals in instance proofs.
   875 
   876 * The transitivity reasoner for partial and linear orders is set up
   877 for classes "order" and "linorder".  Instances of the reasoner are available
   878 in all contexts importing or interpreting the corresponding locales.
   879 Method "order" invokes the reasoner separately; the reasoner
   880 is also integrated with the Simplifier as a solver.  Diagnostic
   881 command 'print_orders' shows the available instances of the reasoner
   882 in the current context.
   883 
   884 * Localized monotonicity predicate in theory "Orderings"; integrated
   885 lemmas max_of_mono and min_of_mono with this predicate.
   886 INCOMPATIBILITY.
   887 
   888 * Formulation of theorem "dense" changed slightly due to integration
   889 with new class dense_linear_order.
   890 
   891 * Uniform lattice theory development in HOL.
   892 
   893     constants "meet" and "join" now named "inf" and "sup"
   894     constant "Meet" now named "Inf"
   895 
   896     classes "meet_semilorder" and "join_semilorder" now named
   897       "lower_semilattice" and "upper_semilattice"
   898     class "lorder" now named "lattice"
   899     class "comp_lat" now named "complete_lattice"
   900 
   901     Instantiation of lattice classes allows explicit definitions
   902     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
   903 
   904   INCOMPATIBILITY.  Theorem renames:
   905 
   906     meet_left_le            ~> inf_le1
   907     meet_right_le           ~> inf_le2
   908     join_left_le            ~> sup_ge1
   909     join_right_le           ~> sup_ge2
   910     meet_join_le            ~> inf_sup_ord
   911     le_meetI                ~> le_infI
   912     join_leI                ~> le_supI
   913     le_meet                 ~> le_inf_iff
   914     le_join                 ~> ge_sup_conv
   915     meet_idempotent         ~> inf_idem
   916     join_idempotent         ~> sup_idem
   917     meet_comm               ~> inf_commute
   918     join_comm               ~> sup_commute
   919     meet_leI1               ~> le_infI1
   920     meet_leI2               ~> le_infI2
   921     le_joinI1               ~> le_supI1
   922     le_joinI2               ~> le_supI2
   923     meet_assoc              ~> inf_assoc
   924     join_assoc              ~> sup_assoc
   925     meet_left_comm          ~> inf_left_commute
   926     meet_left_idempotent    ~> inf_left_idem
   927     join_left_comm          ~> sup_left_commute
   928     join_left_idempotent    ~> sup_left_idem
   929     meet_aci                ~> inf_aci
   930     join_aci                ~> sup_aci
   931     le_def_meet             ~> le_iff_inf
   932     le_def_join             ~> le_iff_sup
   933     join_absorp2            ~> sup_absorb2
   934     join_absorp1            ~> sup_absorb1
   935     meet_absorp1            ~> inf_absorb1
   936     meet_absorp2            ~> inf_absorb2
   937     meet_join_absorp        ~> inf_sup_absorb
   938     join_meet_absorp        ~> sup_inf_absorb
   939     distrib_join_le         ~> distrib_sup_le
   940     distrib_meet_le         ~> distrib_inf_le
   941 
   942     add_meet_distrib_left   ~> add_inf_distrib_left
   943     add_join_distrib_left   ~> add_sup_distrib_left
   944     is_join_neg_meet        ~> is_join_neg_inf
   945     is_meet_neg_join        ~> is_meet_neg_sup
   946     add_meet_distrib_right  ~> add_inf_distrib_right
   947     add_join_distrib_right  ~> add_sup_distrib_right
   948     add_meet_join_distribs  ~> add_sup_inf_distribs
   949     join_eq_neg_meet        ~> sup_eq_neg_inf
   950     meet_eq_neg_join        ~> inf_eq_neg_sup
   951     add_eq_meet_join        ~> add_eq_inf_sup
   952     meet_0_imp_0            ~> inf_0_imp_0
   953     join_0_imp_0            ~> sup_0_imp_0
   954     meet_0_eq_0             ~> inf_0_eq_0
   955     join_0_eq_0             ~> sup_0_eq_0
   956     neg_meet_eq_join        ~> neg_inf_eq_sup
   957     neg_join_eq_meet        ~> neg_sup_eq_inf
   958     join_eq_if              ~> sup_eq_if
   959 
   960     mono_meet               ~> mono_inf
   961     mono_join               ~> mono_sup
   962     meet_bool_eq            ~> inf_bool_eq
   963     join_bool_eq            ~> sup_bool_eq
   964     meet_fun_eq             ~> inf_fun_eq
   965     join_fun_eq             ~> sup_fun_eq
   966     meet_set_eq             ~> inf_set_eq
   967     join_set_eq             ~> sup_set_eq
   968     meet1_iff               ~> inf1_iff
   969     meet2_iff               ~> inf2_iff
   970     meet1I                  ~> inf1I
   971     meet2I                  ~> inf2I
   972     meet1D1                 ~> inf1D1
   973     meet2D1                 ~> inf2D1
   974     meet1D2                 ~> inf1D2
   975     meet2D2                 ~> inf2D2
   976     meet1E                  ~> inf1E
   977     meet2E                  ~> inf2E
   978     join1_iff               ~> sup1_iff
   979     join2_iff               ~> sup2_iff
   980     join1I1                 ~> sup1I1
   981     join2I1                 ~> sup2I1
   982     join1I1                 ~> sup1I1
   983     join2I2                 ~> sup1I2
   984     join1CI                 ~> sup1CI
   985     join2CI                 ~> sup2CI
   986     join1E                  ~> sup1E
   987     join2E                  ~> sup2E
   988 
   989     is_meet_Meet            ~> is_meet_Inf
   990     Meet_bool_def           ~> Inf_bool_def
   991     Meet_fun_def            ~> Inf_fun_def
   992     Meet_greatest           ~> Inf_greatest
   993     Meet_lower              ~> Inf_lower
   994     Meet_set_def            ~> Inf_set_def
   995 
   996     Sup_def                 ~> Sup_Inf
   997     Sup_bool_eq             ~> Sup_bool_def
   998     Sup_fun_eq              ~> Sup_fun_def
   999     Sup_set_eq              ~> Sup_set_def
  1000 
  1001     listsp_meetI            ~> listsp_infI
  1002     listsp_meet_eq          ~> listsp_inf_eq
  1003 
  1004     meet_min                ~> inf_min
  1005     join_max                ~> sup_max
  1006 
  1007 * Added syntactic class "size"; overloaded constant "size" now has
  1008 type "'a::size ==> bool"
  1009 
  1010 * Internal reorganisation of `size' of datatypes: size theorems
  1011 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1012 simplification rules by default!); theorems "prod.size" now named
  1013 "*.size".
  1014 
  1015 * Class "div" now inherits from class "times" rather than "type".
  1016 INCOMPATIBILITY.
  1017 
  1018 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1019 Linorder etc.  have disappeared; operations defined in terms of
  1020 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1021 
  1022 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1023 
  1024 * HOL-Word: New extensive library and type for generic, fixed size
  1025 machine words, with arithemtic, bit-wise, shifting and rotating
  1026 operations, reflection into int, nat, and bool lists, automation for
  1027 linear arithmetic (by automatic reflection into nat or int), including
  1028 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1029 arithmetic type classes, supporting automatic simplification of
  1030 numerals on all operations.
  1031 
  1032 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1033 
  1034 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1035 
  1036 * Code generator library theories:
  1037   - Code_Integer represents HOL integers by big integer literals in target
  1038     languages.
  1039   - Code_Char represents HOL characters by character literals in target
  1040     languages.
  1041   - Code_Char_chr like Code_Char, but also offers treatment of character
  1042     codes; includes Code_Integer.
  1043   - Executable_Set allows to generate code for finite sets using lists.
  1044   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1045     denominator).
  1046   - Executable_Real implements a subset of real numbers, namly those
  1047     representable by rational numbers.
  1048   - Efficient_Nat implements natural numbers by integers, which in general will
  1049     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1050     includes Code_Integer.
  1051   - Code_Index provides an additional datatype index which is mapped to
  1052     target-language built-in integers.
  1053   - Code_Message provides an additional datatype message_string which is isomorphic to
  1054     strings; messages are mapped to target-language strings.
  1055 
  1056 * New package for inductive predicates
  1057 
  1058   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1059 
  1060     inductive
  1061       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1062       for z_1 :: U_1 and ... and z_n :: U_m
  1063     where
  1064       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1065     | ...
  1066 
  1067   with full support for type-inference, rather than
  1068 
  1069     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1070 
  1071     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1072     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1073 
  1074     inductive "s z_1 ... z_m"
  1075     intros
  1076       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1077       ...
  1078 
  1079   For backward compatibility, there is a wrapper allowing inductive
  1080   sets to be defined with the new package via
  1081 
  1082     inductive_set
  1083       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1084       for z_1 :: U_1 and ... and z_n :: U_m
  1085     where
  1086       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1087     | ...
  1088 
  1089   or
  1090 
  1091     inductive_set
  1092       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1093       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1094       for z_1 :: U_1 and ... and z_n :: U_m
  1095     where
  1096       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1097     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1098     | ...
  1099 
  1100   if the additional syntax "p ..." is required.
  1101 
  1102   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1103   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1104 
  1105   INCOMPATIBILITIES:
  1106 
  1107   - Since declaration and definition of inductive sets or predicates
  1108     is no longer separated, abbreviations involving the newly
  1109     introduced sets or predicates must be specified together with the
  1110     introduction rules after the 'where' keyword (see above), rather
  1111     than before the actual inductive definition.
  1112 
  1113   - The variables in induction and elimination rules are now
  1114     quantified in the order of their occurrence in the introduction
  1115     rules, rather than in alphabetical order. Since this may break
  1116     some proofs, these proofs either have to be repaired, e.g. by
  1117     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1118     statements of the form
  1119 
  1120       case (rule_i a_i_1 ... a_i_{k_i})
  1121 
  1122     or the old order of quantification has to be restored by explicitly adding
  1123     meta-level quantifiers in the introduction rules, i.e.
  1124 
  1125       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1126 
  1127   - The format of the elimination rules is now
  1128 
  1129       p z_1 ... z_m x_1 ... x_n ==>
  1130         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1131         ==> ... ==> P
  1132 
  1133     for predicates and
  1134 
  1135       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1136         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1137         ==> ... ==> P
  1138 
  1139     for sets rather than
  1140 
  1141       x : s z_1 ... z_m ==>
  1142         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1143         ==> ... ==> P
  1144 
  1145     This may require terms in goals to be expanded to n-tuples
  1146     (e.g. using case_tac or simplification with the split_paired_all
  1147     rule) before the above elimination rule is applicable.
  1148 
  1149   - The elimination or case analysis rules for (mutually) inductive
  1150     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1151     list of rules "p_1_..._p_k.elims" is no longer available.
  1152 
  1153 * New package "function"/"fun" for general recursive functions,
  1154 supporting mutual and nested recursion, definitions in local contexts,
  1155 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1156 for small examples, and the separate tutorial on the function
  1157 package. The old recdef "package" is still available as before, but
  1158 users are encouraged to use the new package.
  1159 
  1160 * Method "lexicographic_order" automatically synthesizes termination
  1161 relations as lexicographic combinations of size measures. 
  1162 
  1163 * Case-expressions allow arbitrary constructor-patterns (including
  1164 "_") and take their order into account, like in functional
  1165 programming.  Internally, this is translated into nested
  1166 case-expressions; missing cases are added and mapped to the predefined
  1167 constant "undefined". In complicated cases printing may no longer show
  1168 the original input but the internal form. Lambda-abstractions allow
  1169 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1170 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1171 variable.
  1172 
  1173 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1174 is an abbreviation for "of_nat :: nat => int". The simplification
  1175 rules for "of_nat" have been changed to work like "int" did
  1176 previously.  Potential INCOMPATIBILITY:
  1177   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1178   - of_nat_diff and of_nat_mult are no longer default simp rules
  1179 
  1180 * Method "algebra" solves polynomial equations over (semi)rings using
  1181 Groebner bases. The (semi)ring structure is defined by locales and the
  1182 tool setup depends on that generic context. Installing the method for
  1183 a specific type involves instantiating the locale and possibly adding
  1184 declarations for computation on the coefficients.  The method is
  1185 already instantiated for natural numbers and for the axiomatic class
  1186 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1187 CALCULEMUS 2007 for the general principles underlying this
  1188 architecture of context-aware proof-tools.
  1189 
  1190 * Method "ferrack" implements quantifier elimination over
  1191 special-purpose dense linear orders using locales (analogous to
  1192 "algebra"). The method is already installed for class
  1193 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1194 rat, etc.
  1195 
  1196 * Former constant "List.op @" now named "List.append".  Use ML
  1197 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1198 circumvent possible incompatibilities when working on ML level.
  1199 
  1200 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1201 
  1202 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1203 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1204 
  1205 * New syntax for Haskell-like list comprehension (input only), eg.
  1206 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1207 
  1208 * The special syntax for function "filter" has changed from [x :
  1209 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1210 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1211 
  1212 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1213 defined on nat only, as an abbreviation for [a..<Suc b]
  1214 INCOMPATIBILITY.
  1215 
  1216 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1217 
  1218 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1219 
  1220 * New lemma collection field_simps (an extension of ring_simps) for
  1221 manipulating (in)equations involving division. Multiplies with all
  1222 denominators that can be proved to be non-zero (in equations) or
  1223 positive/negative (in inequations).
  1224 
  1225 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1226 have been improved and renamed to ring_simps, group_simps and
  1227 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1228 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1229 
  1230 * Theory Library/Commutative_Ring: switched from recdef to function
  1231 package; constants add, mul, pow now curried.  Infix syntax for
  1232 algebraic operations.
  1233 
  1234 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1235 INCOMPATIBILITY.
  1236 
  1237 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1238 INCOMPATIBILITY.
  1239 
  1240 * HOL/records: generalised field-update to take a function on the
  1241 field rather than the new value: r(|A := x|) is translated to A_update
  1242 (K x) r The K-combinator that is internally used is called K_record.
  1243 INCOMPATIBILITY: Usage of the plain update functions has to be
  1244 adapted.
  1245  
  1246 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1247 * x = 0, which are required for a semiring.  Richer structures do not
  1248 inherit from semiring_0 anymore, because this property is a theorem
  1249 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1250 there is more to prove, but this is mostly trivial.
  1251 
  1252 * Class "recpower" is generalized to arbitrary monoids, not just
  1253 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1254 commutativity or semiring properties additionally.
  1255 
  1256 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1257 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1258 better use 'abbreviation'.
  1259 
  1260 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1261 
  1262 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1263 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1264 significant changes for setting up numeral syntax for types:
  1265   - New constants Numeral.pred and Numeral.succ instead
  1266       of former Numeral.bin_pred and Numeral.bin_succ.
  1267   - Use integer operations instead of bin_add, bin_mult and so on.
  1268   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1269   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1270 
  1271 See src/HOL/Integ/IntArith.thy for an example setup.
  1272 
  1273 * Command 'normal_form' computes the normal form of a term that may
  1274 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1275 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1276 heavy-duty computations because the functions are compiled to ML
  1277 first.  Correspondingly, a method "normalization" is provided.  See
  1278 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1279 
  1280 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1281 25 like -->); output depends on the "iff" print_mode, the default is
  1282 "A = B" (with priority 50).
  1283 
  1284 * Relations less (<) and less_eq (<=) are also available on type bool.
  1285 Modified syntax to disallow nesting without explicit parentheses,
  1286 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1287 INCOMPATIBILITY.
  1288 
  1289 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1290 
  1291 * Relation composition operator "op O" now has precedence 75 and binds
  1292 stronger than union and intersection. INCOMPATIBILITY.
  1293 
  1294 * The old set interval syntax "{m..n(}" (and relatives) has been
  1295 removed.  Use "{m..<n}" (and relatives) instead.
  1296 
  1297 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1298 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1299 ``declare [[simproc del: neq]]''.
  1300 
  1301 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1302 True/False.
  1303 
  1304 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1305 
  1306 * Theorem setsum_mult renamed to setsum_right_distrib.
  1307 
  1308 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1309 ``rule'' method.
  1310 
  1311 * Reimplemented methods "sat" and "satx", with several improvements:
  1312 goals no longer need to be stated as "<prems> ==> False", equivalences
  1313 (i.e. "=" on type bool) are handled, variable names of the form
  1314 "lit_<n>" are no longer reserved, significant speedup.
  1315 
  1316 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1317 zChaff is still supported as well.
  1318 
  1319 * 'inductive' and 'datatype': provide projections of mutual rules,
  1320 bundled as foo_bar.inducts;
  1321 
  1322 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1323 Library.
  1324 
  1325 * Library: moved theory Accessible_Part to main HOL.
  1326 
  1327 * Library: added theory Coinductive_List of potentially infinite lists
  1328 as greatest fixed-point.
  1329 
  1330 * Library: added theory AssocList which implements (finite) maps as
  1331 association lists.
  1332 
  1333 * Method "evaluation" solves goals (i.e. a boolean expression)
  1334 efficiently by compiling it to ML.  The goal is "proved" (via an
  1335 oracle) if it evaluates to True.
  1336 
  1337 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1338 also when invoked by the simplifier.  This results in the Simplifier
  1339 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1340 Configuration option fast_arith_split_limit=0 recovers the old
  1341 behavior.
  1342 
  1343 * Support for hex (0x20) and binary (0b1001) numerals.
  1344 
  1345 * New method: reify eqs (t), where eqs are equations for an
  1346 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1347 parameter, computes a term s::'b and a list xs::'a list and proves the
  1348 theorem I xs s = t. This is also known as reification or quoting. The
  1349 resulting theorem is applied to the subgoal to substitute t with I xs
  1350 s.  If t is omitted, the subgoal itself is reified.
  1351 
  1352 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1353 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1354 where f is supposed to be a computable function (in the sense of code
  1355 generattion). The method uses reify to compute s and xs as above then
  1356 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1357 r and finally gets the theorem t = r, which is again applied to the
  1358 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1359 
  1360 * Reflection: Automatic reification now handels binding, an example is
  1361 available in src/HOL/ex/ReflectionEx.thy
  1362 
  1363 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1364 command 'statespace' that is similar to 'record', but introduces an
  1365 abstract specification based on the locale infrastructure instead of
  1366 HOL types.  This leads to extra flexibility in composing state spaces,
  1367 in particular multiple inheritance and renaming of components.
  1368 
  1369 
  1370 *** HOL-Complex ***
  1371 
  1372 * Hyperreal: Functions root and sqrt are now defined on negative real
  1373 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1374 Nonnegativity side conditions have been removed from many lemmas, so
  1375 that more subgoals may now be solved by simplification; potential
  1376 INCOMPATIBILITY.
  1377 
  1378 * Real: new type classes formalize real normed vector spaces and
  1379 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1380 and norm :: 'a => real.
  1381 
  1382 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1383 reals into other types. The overloaded constant Reals :: 'a set is now
  1384 defined as range of_real; potential INCOMPATIBILITY.
  1385 
  1386 * Real: proper support for ML code generation, including 'quickcheck'.
  1387 Reals are implemented as arbitrary precision rationals.
  1388 
  1389 * Hyperreal: Several constants that previously worked only for the
  1390 reals have been generalized, so they now work over arbitrary vector
  1391 spaces. Type annotations may need to be added in some cases; potential
  1392 INCOMPATIBILITY.
  1393 
  1394   Infinitesimal  :: ('a::real_normed_vector) star set
  1395   HFinite        :: ('a::real_normed_vector) star set
  1396   HInfinite      :: ('a::real_normed_vector) star set
  1397   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1398   monad          :: ('a::real_normed_vector) star => 'a star set
  1399   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1400   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1401   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1402   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1403   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1404   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1405   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1406   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1407   sgn            :: 'a::real_normed_vector => 'a
  1408   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1409 
  1410 * Complex: Some complex-specific constants are now abbreviations for
  1411 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1412 hnorm.  Other constants have been entirely removed in favor of the
  1413 polymorphic versions (INCOMPATIBILITY):
  1414 
  1415   approx        <-- capprox
  1416   HFinite       <-- CFinite
  1417   HInfinite     <-- CInfinite
  1418   Infinitesimal <-- CInfinitesimal
  1419   monad         <-- cmonad
  1420   galaxy        <-- cgalaxy
  1421   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1422   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1423   (ns)deriv     <-- (ns)cderiv
  1424 
  1425 
  1426 *** HOL-Algebra ***
  1427 
  1428 * Formalisation of ideals and the quotient construction over rings.
  1429 
  1430 * Order and lattice theory no longer based on records.
  1431 INCOMPATIBILITY.
  1432 
  1433 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1434 greatest_closed.  INCOMPATIBILITY.
  1435 
  1436 * Method algebra is now set up via an attribute.  For examples see
  1437 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1438 of algebraic structures.
  1439 
  1440 * Renamed theory CRing to Ring.
  1441 
  1442 
  1443 *** HOL-Nominal ***
  1444 
  1445 * Substantial, yet incomplete support for nominal datatypes (binding
  1446 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  1447 src/HOL/Nominal/Examples.  Prospective users should consult
  1448 http://isabelle.in.tum.de/nominal/
  1449 
  1450 
  1451 *** ML ***
  1452 
  1453 * ML basics: just one true type int, which coincides with IntInf.int
  1454 (even on SML/NJ).
  1455 
  1456 * ML within Isar: antiquotations allow to embed statically-checked
  1457 formal entities in the source, referring to the context available at
  1458 compile-time.  For example:
  1459 
  1460 ML {* @{sort "{zero,one}"} *}
  1461 ML {* @{typ "'a => 'b"} *}
  1462 ML {* @{term "%x. x"} *}
  1463 ML {* @{prop "x == y"} *}
  1464 ML {* @{ctyp "'a => 'b"} *}
  1465 ML {* @{cterm "%x. x"} *}
  1466 ML {* @{cprop "x == y"} *}
  1467 ML {* @{thm asm_rl} *}
  1468 ML {* @{thms asm_rl} *}
  1469 ML {* @{type_name c} *}
  1470 ML {* @{type_syntax c} *}
  1471 ML {* @{const_name c} *}
  1472 ML {* @{const_syntax c} *}
  1473 ML {* @{context} *}
  1474 ML {* @{theory} *}
  1475 ML {* @{theory Pure} *}
  1476 ML {* @{theory_ref} *}
  1477 ML {* @{theory_ref Pure} *}
  1478 ML {* @{simpset} *}
  1479 ML {* @{claset} *}
  1480 ML {* @{clasimpset} *}
  1481 
  1482 The same works for sources being ``used'' within an Isar context.
  1483 
  1484 * ML in Isar: improved error reporting; extra verbosity with
  1485 ML_Context.trace enabled.
  1486 
  1487 * Pure/General/table.ML: the join operations now works via exceptions
  1488 DUP/SAME instead of type option. This is simpler in simple cases, and
  1489 admits slightly more efficient complex applications.
  1490 
  1491 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1492 use Context.generic instead of just theory.
  1493 
  1494 * Pure: datatype Context.generic joins theory/Proof.context and
  1495 provides some facilities for code that works in either kind of
  1496 context, notably GenericDataFun for uniform theory and proof data.
  1497 
  1498 * Pure: simplified internal attribute type, which is now always
  1499 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  1500 local (Proof.context) attributes have been discontinued, while
  1501 minimizing code duplication. Thm.rule_attribute and
  1502 Thm.declaration_attribute build canonical attributes; see also structure
  1503 Context for further operations on Context.generic, notably
  1504 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  1505 declarations and definitions.
  1506 
  1507 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1508 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1509 init only required for impure data. INCOMPATIBILITY: empty really need
  1510 to be empty (no dependencies on theory content!)
  1511 
  1512 * Pure/kernel: consts certification ignores sort constraints given in
  1513 signature declarations. (This information is not relevant to the
  1514 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  1515 potential INCOMPATIBILITY.
  1516 
  1517 * Pure: axiomatic type classes are now purely definitional, with
  1518 explicit proofs of class axioms and super class relations performed
  1519 internally. See Pure/axclass.ML for the main internal interfaces --
  1520 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1521 AxClass.axiomatize_class/classrel/arity supersede
  1522 Sign.add_classes/classrel/arities.
  1523 
  1524 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1525 global/local versions on theory vs. Proof.context have been
  1526 discontinued; Attrib.syntax and Method.syntax have been adapted
  1527 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1528 attributes, methods, etc.
  1529 
  1530 * Pure: several functions of signature "... -> theory -> theory * ..."
  1531 have been reoriented to "... -> theory -> ... * theory" in order to
  1532 allow natural usage in combination with the ||>, ||>>, |-> and
  1533 fold_map combinators.
  1534 
  1535 * Pure: official theorem names (closed derivations) and additional
  1536 comments (tags) are now strictly separate.  Name hints -- which are
  1537 maintained as tags -- may be attached any time without affecting the
  1538 derivation.
  1539 
  1540 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1541 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1542 achieve the old behaviour.
  1543 
  1544 * Pure: the "Goal" constant is now called "prop", supporting a
  1545 slightly more general idea of ``protecting'' meta-level rule
  1546 statements.
  1547 
  1548 * Pure: Logic.(un)varify only works in a global context, which is now
  1549 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1550 Logic.legacy_(un)varify as temporary workaround.
  1551 
  1552 * Pure: structure Name provides scalable operations for generating
  1553 internal variable names, notably Name.variants etc.  This replaces
  1554 some popular functions from term.ML:
  1555 
  1556   Term.variant		->  Name.variant
  1557   Term.variantlist	->  Name.variant_list
  1558   Term.invent_names	->  Name.invent_list
  1559 
  1560 Note that low-level renaming rarely occurs in new code -- operations
  1561 from structure Variable are used instead (see below).
  1562 
  1563 * Pure: structure Variable provides fundamental operations for proper
  1564 treatment of fixed/schematic variables in a context.  For example,
  1565 Variable.import introduces fixes for schematics of given facts and
  1566 Variable.export reverses the effect (up to renaming) -- this replaces
  1567 various freeze_thaw operations.
  1568 
  1569 * Pure: structure Goal provides simple interfaces for
  1570 init/conclude/finish and tactical prove operations (replacing former
  1571 Tactic.prove).  Goal.prove is the canonical way to prove results
  1572 within a given context; Goal.prove_global is a degraded version for
  1573 theory level goals, including a global Drule.standard.  Note that
  1574 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1575 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1576 in a locale context).
  1577 
  1578 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  1579 and type checking (Syntax.check_term etc.), with common combinations
  1580 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  1581 which are considered legacy and await removal.
  1582 
  1583 * Pure/Syntax: generic interfaces for type unchecking
  1584 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  1585 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  1586 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  1587 available for convenience, but refer to the very same operations using
  1588 a mere theory instead of a full context.
  1589 
  1590 * Isar: simplified treatment of user-level errors, using exception
  1591 ERROR of string uniformly.  Function error now merely raises ERROR,
  1592 without any side effect on output channels.  The Isar toplevel takes
  1593 care of proper display of ERROR exceptions.  ML code may use plain
  1594 handle/can/try; cat_error may be used to concatenate errors like this:
  1595 
  1596   ... handle ERROR msg => cat_error msg "..."
  1597 
  1598 Toplevel ML code (run directly or through the Isar toplevel) may be
  1599 embedded into the Isar toplevel with exception display/debug like
  1600 this:
  1601 
  1602   Isar.toplevel (fn () => ...)
  1603 
  1604 INCOMPATIBILITY, removed special transform_error facilities, removed
  1605 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1606 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1607 -- use plain ERROR instead.
  1608 
  1609 * Isar: theory setup now has type (theory -> theory), instead of a
  1610 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1611 
  1612 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  1613 ProofContext.debug/verbose flags.
  1614 
  1615 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1616 theory before entering a proof state.  Transactions now always see a
  1617 quasi-functional intermediate checkpoint, both in interactive and
  1618 batch mode.
  1619 
  1620 * Isar: simplified interfaces for outer syntax.  Renamed
  1621 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  1622 OuterSyntax.add_parsers -- this functionality is now included in
  1623 OuterSyntax.command etc.  INCOMPATIBILITY.
  1624 
  1625 * Simplifier: the simpset of a running simplification process now
  1626 contains a proof context (cf. Simplifier.the_context), which is the
  1627 very context that the initial simpset has been retrieved from (by
  1628 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1629 (solver, looper etc.) may depend on arbitrary proof data.
  1630 
  1631 * Simplifier.inherit_context inherits the proof context (plus the
  1632 local bounds) of the current simplification process; any simproc
  1633 etc. that calls the Simplifier recursively should do this!  Removed
  1634 former Simplifier.inherit_bounds, which is already included here --
  1635 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1636 specify an explicit context using Simplifier.context/theory_context.
  1637 
  1638 * Simplifier/Classical Reasoner: more abstract interfaces
  1639 change_simpset/claset for modifying the simpset/claset reference of a
  1640 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1641 INCOMPATIBILITY.
  1642 
  1643 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1644 "Trueprop" etc.
  1645 
  1646 
  1647 *** System ***
  1648 
  1649 * settings: the default heap location within ISABELLE_HOME_USER now
  1650 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  1651 Isabelle installations.
  1652 
  1653 * isabelle-process: option -S (secure mode) disables some critical
  1654 operations, notably runtime compilation and evaluation of ML source
  1655 code.
  1656 
  1657 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  1658 
  1659 * Support for parallel execution, using native multicore support of
  1660 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  1661 independent theories, according to the given theory header
  1662 specifications. The maximum number of worker threads is specified via
  1663 usedir option -M or the "max-threads" setting in Proof General. A
  1664 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  1665 to 6 on a 8-core machine.  User-code needs to observe certain
  1666 guidelines for thread-safe programming, see appendix A in the Isar
  1667 Implementation manual.
  1668 
  1669 
  1670 
  1671 New in Isabelle2005 (October 2005)
  1672 ----------------------------------
  1673 
  1674 *** General ***
  1675 
  1676 * Theory headers: the new header syntax for Isar theories is
  1677 
  1678   theory <name>
  1679   imports <theory1> ... <theoryN>
  1680   uses <file1> ... <fileM>
  1681   begin
  1682 
  1683 where the 'uses' part is optional.  The previous syntax
  1684 
  1685   theory <name> = <theory1> + ... + <theoryN>:
  1686 
  1687 will disappear in the next release.  Use isatool fixheaders to convert
  1688 existing theory files.  Note that there is no change in ancient
  1689 non-Isar theories now, but these will disappear soon.
  1690 
  1691 * Theory loader: parent theories can now also be referred to via
  1692 relative and absolute paths.
  1693 
  1694 * Command 'find_theorems' searches for a list of criteria instead of a
  1695 list of constants. Known criteria are: intro, elim, dest, name:string,
  1696 simp:term, and any term. Criteria can be preceded by '-' to select
  1697 theorems that do not match. Intro, elim, dest select theorems that
  1698 match the current goal, name:s selects theorems whose fully qualified
  1699 name contain s, and simp:term selects all simplification rules whose
  1700 lhs match term.  Any other term is interpreted as pattern and selects
  1701 all theorems matching the pattern. Available in ProofGeneral under
  1702 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1703 
  1704   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1705 
  1706 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1707 matching the current goal as introduction rule and not having "HOL."
  1708 in their name (i.e. not being defined in theory HOL).
  1709 
  1710 * Command 'thms_containing' has been discontinued in favour of
  1711 'find_theorems'; INCOMPATIBILITY.
  1712 
  1713 * Communication with Proof General is now 8bit clean, which means that
  1714 Unicode text in UTF-8 encoding may be used within theory texts (both
  1715 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1716 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1717 
  1718   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1719   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1720 
  1721 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1722 Classical Reasoner.  Typical big applications run around 2 times
  1723 faster.
  1724 
  1725 
  1726 *** Document preparation ***
  1727 
  1728 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1729 of raw sources.  Only those symbols that do not require additional
  1730 LaTeX packages (depending on comments in isabellesym.sty) are
  1731 displayed properly, everything else is left verbatim.  isatool display
  1732 and isatool print are used as front ends (these are subject to the
  1733 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1734 
  1735 * Command tags control specific markup of certain regions of text,
  1736 notably folding and hiding.  Predefined tags include "theory" (for
  1737 theory begin and end), "proof" for proof commands, and "ML" for
  1738 commands involving ML code; the additional tags "visible" and
  1739 "invisible" are unused by default.  Users may give explicit tag
  1740 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1741 interpretation of tags is determined by the LaTeX job during document
  1742 preparation: see option -V of isatool usedir, or options -n and -t of
  1743 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1744 \isadroptag.
  1745 
  1746 Several document versions may be produced at the same time via isatool
  1747 usedir (the generated index.html will link all of them).  Typical
  1748 specifications include ''-V document=theory,proof,ML'' to present
  1749 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1750 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1751 these parts without any formal replacement text.  The Isabelle site
  1752 default settings produce ''document'' and ''outline'' versions as
  1753 specified above.
  1754 
  1755 * Several new antiquotations:
  1756 
  1757   @{term_type term} prints a term with its type annotated;
  1758 
  1759   @{typeof term} prints the type of a term;
  1760 
  1761   @{const const} is the same as @{term const}, but checks that the
  1762   argument is a known logical constant;
  1763 
  1764   @{term_style style term} and @{thm_style style thm} print a term or
  1765   theorem applying a "style" to it
  1766 
  1767   @{ML text}
  1768 
  1769 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1770 definitions, equations, inequations etc., 'concl' printing only the
  1771 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1772 to print the specified premise.  TermStyle.add_style provides an ML
  1773 interface for introducing further styles.  See also the "LaTeX Sugar"
  1774 document practical applications.  The ML antiquotation prints
  1775 type-checked ML expressions verbatim.
  1776 
  1777 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1778 and 'text' support optional locale specification '(in loc)', which
  1779 specifies the default context for interpreting antiquotations.  For
  1780 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1781 
  1782 * Option 'locale=NAME' of antiquotations specifies an alternative
  1783 context interpreting the subsequent argument.  For example: @{thm
  1784 [locale=lattice] inf_assoc}.
  1785 
  1786 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1787 a proof context.
  1788 
  1789 * Proper output of antiquotations for theory commands involving a
  1790 proof context (such as 'locale' or 'theorem (in loc) ...').
  1791 
  1792 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1793 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1794 
  1795 * isatool usedir: new option -C (default true) controls whether option
  1796 -D should include a copy of the original document directory; -C false
  1797 prevents unwanted effects such as copying of administrative CVS data.
  1798 
  1799 
  1800 *** Pure ***
  1801 
  1802 * Considerably improved version of 'constdefs' command.  Now performs
  1803 automatic type-inference of declared constants; additional support for
  1804 local structure declarations (cf. locales and HOL records), see also
  1805 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1806 sequential dependencies of definitions within a single 'constdefs'
  1807 section; moreover, the declared name needs to be an identifier.  If
  1808 all fails, consider to fall back on 'consts' and 'defs' separately.
  1809 
  1810 * Improved indexed syntax and implicit structures.  First of all,
  1811 indexed syntax provides a notational device for subscripted
  1812 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1813 expressions.  Secondly, in a local context with structure
  1814 declarations, number indexes \<^sub>n or the empty index (default
  1815 number 1) refer to a certain fixed variable implicitly; option
  1816 show_structs controls printing of implicit structures.  Typical
  1817 applications of these concepts involve record types and locales.
  1818 
  1819 * New command 'no_syntax' removes grammar declarations (and
  1820 translations) resulting from the given syntax specification, which is
  1821 interpreted in the same manner as for the 'syntax' command.
  1822 
  1823 * 'Advanced' translation functions (parse_translation etc.) may depend
  1824 on the signature of the theory context being presently used for
  1825 parsing/printing, see also isar-ref manual.
  1826 
  1827 * Improved 'oracle' command provides a type-safe interface to turn an
  1828 ML expression of type theory -> T -> term into a primitive rule of
  1829 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1830 is already included here); see also FOL/ex/IffExample.thy;
  1831 INCOMPATIBILITY.
  1832 
  1833 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1834 before); "cI" is no longer bound, use "c.intro" instead.
  1835 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1836 axclasses vs. locales.
  1837 
  1838 * Improved internal renaming of symbolic identifiers -- attach primes
  1839 instead of base 26 numbers.
  1840 
  1841 * New flag show_question_marks controls printing of leading question
  1842 marks in schematic variable names.
  1843 
  1844 * In schematic variable names, *any* symbol following \<^isub> or
  1845 \<^isup> is now treated as part of the base name.  For example, the
  1846 following works without printing of awkward ".0" indexes:
  1847 
  1848   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1849     by simp
  1850 
  1851 * Inner syntax includes (*(*nested*) comments*).
  1852 
  1853 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1854 annotations as "(00...)".
  1855 
  1856 * Clear separation of logical types and nonterminals, where the latter
  1857 may only occur in 'syntax' specifications or type abbreviations.
  1858 Before that distinction was only partially implemented via type class
  1859 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1860 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1861 exotic syntax specifications may require further adaption
  1862 (e.g. Cube/Cube.thy).
  1863 
  1864 * Removed obsolete type class "logic", use the top sort {} instead.
  1865 Note that non-logical types should be declared as 'nonterminals'
  1866 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1867 specifications.
  1868 
  1869 * Attributes 'induct' and 'cases': type or set names may now be
  1870 locally fixed variables as well.
  1871 
  1872 * Simplifier: can now control the depth to which conditional rewriting
  1873 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1874 Limit.
  1875 
  1876 * Simplifier: simplification procedures may now take the current
  1877 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1878 interface), which is very useful for calling the Simplifier
  1879 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1880 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1881 low-level mk_simproc no longer applies Logic.varify internally, to
  1882 allow for use in a context of fixed variables.
  1883 
  1884 * thin_tac now works even if the assumption being deleted contains !!
  1885 or ==>.  More generally, erule now works even if the major premise of
  1886 the elimination rule contains !! or ==>.
  1887 
  1888 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1889 
  1890 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1891 from Pure, which contains all common declarations already.  Both
  1892 theories are defined via plain Isabelle/Isar .thy files.
  1893 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1894 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1895 use isatool fixcpure to adapt your theory and ML sources.
  1896 
  1897 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1898 selections of theorems in named facts via index ranges.
  1899 
  1900 * 'print_theorems': in theory mode, really print the difference
  1901 wrt. the last state (works for interactive theory development only),
  1902 in proof mode print all local facts (cf. 'print_facts');
  1903 
  1904 * 'hide': option '(open)' hides only base names.
  1905 
  1906 * More efficient treatment of intermediate checkpoints in interactive
  1907 theory development.
  1908 
  1909 * Code generator is now invoked via code_module (incremental code
  1910 generation) and code_library (modular code generation, ML structures
  1911 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1912 must be quoted when used as identifiers.
  1913 
  1914 * New 'value' command for reading, evaluating and printing terms using
  1915 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1916 quoted when used as identifier.
  1917 
  1918 
  1919 *** Locales ***
  1920 
  1921 * New commands for the interpretation of locale expressions in
  1922 theories (1), locales (2) and proof contexts (3).  These generate
  1923 proof obligations from the expression specification.  After the
  1924 obligations have been discharged, theorems of the expression are added
  1925 to the theory, target locale or proof context.  The synopsis of the
  1926 commands is a follows:
  1927 
  1928   (1) interpretation expr inst
  1929   (2) interpretation target < expr
  1930   (3) interpret expr inst
  1931 
  1932 Interpretation in theories and proof contexts require a parameter
  1933 instantiation of terms from the current context.  This is applied to
  1934 specifications and theorems of the interpreted expression.
  1935 Interpretation in locales only permits parameter renaming through the
  1936 locale expression.  Interpretation is smart in that interpretations
  1937 that are active already do not occur in proof obligations, neither are
  1938 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1939 inspect active interpretations of a particular locale.  For details,
  1940 see the Isar Reference manual.  Examples can be found in
  1941 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1942 
  1943 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1944 'interpret' instead.
  1945 
  1946 * New context element 'constrains' for adding type constraints to
  1947 parameters.
  1948 
  1949 * Context expressions: renaming of parameters with syntax
  1950 redeclaration.
  1951 
  1952 * Locale declaration: 'includes' disallowed.
  1953 
  1954 * Proper static binding of attribute syntax -- i.e. types / terms /
  1955 facts mentioned as arguments are always those of the locale definition
  1956 context, independently of the context of later invocations.  Moreover,
  1957 locale operations (renaming and type / term instantiation) are applied
  1958 to attribute arguments as expected.
  1959 
  1960 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1961 actual attributes; rare situations may require Attrib.attribute to
  1962 embed those attributes into Attrib.src that lack concrete syntax.
  1963 Attribute implementations need to cooperate properly with the static
  1964 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1965 Attrib.XXX_thm etc. already do the right thing without further
  1966 intervention.  Only unusual applications -- such as "where" or "of"
  1967 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1968 on the context and the facts involved -- may have to assign parsed
  1969 values to argument tokens explicitly.
  1970 
  1971 * Changed parameter management in theorem generation for long goal
  1972 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1973 theorem statement in rare situations.
  1974 
  1975 * Locale inspection command 'print_locale' omits notes elements.  Use
  1976 'print_locale!' to have them included in the output.
  1977 
  1978 
  1979 *** Provers ***
  1980 
  1981 * Provers/hypsubst.ML: improved version of the subst method, for
  1982 single-step rewriting: it now works in bound variable contexts. New is
  1983 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1984 rewrite a different subterm than the original subst method, which is
  1985 still available as 'simplesubst'.
  1986 
  1987 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1988 and quasi orders.
  1989 
  1990 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1991 reflexive-transitive closure of relations.
  1992 
  1993 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1994 limit (previously hard-coded with a value of 20) user-definable.
  1995 
  1996 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1997 is peformed already.  Object-logics merely need to finish their
  1998 initial simpset configuration as before.  INCOMPATIBILITY.
  1999 
  2000 
  2001 *** HOL ***
  2002 
  2003 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2004 
  2005   syntax (epsilon)
  2006     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2007 
  2008 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2009 and x-symbol; use option '-m epsilon' to get it actually printed.
  2010 Moreover, the mathematically important symbolic identifier \<epsilon>
  2011 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2012 
  2013 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2014 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2015 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2016 support corresponding Isar calculations.
  2017 
  2018 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2019 instead of ":".
  2020 
  2021 * theory SetInterval: changed the syntax for open intervals:
  2022 
  2023   Old       New
  2024   {..n(}    {..<n}
  2025   {)n..}    {n<..}
  2026   {m..n(}   {m..<n}
  2027   {)m..n}   {m<..n}
  2028   {)m..n(}  {m<..<n}
  2029 
  2030 The old syntax is still supported but will disappear in the next
  2031 release.  For conversion use the following Emacs search and replace
  2032 patterns (these are not perfect but work quite well):
  2033 
  2034   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2035   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2036 
  2037 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2038 equalities in commutative rings; method 'algebra' provides a generic
  2039 interface.
  2040 
  2041 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2042 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2043 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2044 be a tuple pattern.
  2045 
  2046 Some new syntax forms are available:
  2047 
  2048   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2049   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2050   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2051   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2052 
  2053 The latter form "\<Sum>x < k. e" used to be based on a separate
  2054 function "Summation", which has been discontinued.
  2055 
  2056 * theory Finite_Set: in structured induction proofs, the insert case
  2057 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2058 (insert F x)'.
  2059 
  2060 * The 'refute' command has been extended to support a much larger
  2061 fragment of HOL, including axiomatic type classes, constdefs and
  2062 typedefs, inductive datatypes and recursion.
  2063 
  2064 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2065 Requires zChaff with proof generation to be installed.  See
  2066 HOL/ex/SAT_Examples.thy for examples.
  2067 
  2068 * Datatype induction via method 'induct' now preserves the name of the
  2069 induction variable. For example, when proving P(xs::'a list) by
  2070 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2071 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2072 in unstructured proof scripts.
  2073 
  2074 * Reworked implementation of records.  Improved scalability for
  2075 records with many fields, avoiding performance problems for type
  2076 inference. Records are no longer composed of nested field types, but
  2077 of nested extension types. Therefore the record type only grows linear
  2078 in the number of extensions and not in the number of fields.  The
  2079 top-level (users) view on records is preserved.  Potential
  2080 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2081 old record representation. The type generated for a record is called
  2082 <record_name>_ext_type.
  2083 
  2084 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2085 proofs triggered by a record definition or a simproc (if
  2086 quick_and_dirty is enabled).  Definitions of large records can take
  2087 quite long.
  2088 
  2089 New simproc record_upd_simproc for simplification of multiple record
  2090 updates enabled by default.  Moreover, trivial updates are also
  2091 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2092 occasionally, since simplification is more powerful by default.
  2093 
  2094 * typedef: proper support for polymorphic sets, which contain extra
  2095 type-variables in the term.
  2096 
  2097 * Simplifier: automatically reasons about transitivity chains
  2098 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2099 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2100 old proofs break occasionally as simplification may now solve more
  2101 goals than previously.
  2102 
  2103 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2104 present.  Works for all partial orders (class "order"), in particular
  2105 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2106 just like y <= x.
  2107 
  2108 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2109 bound variable or a constant then the let is unfolded.  Otherwise
  2110 first a is simplified to b, and then f b is simplified to g. If
  2111 possible we abstract b from g arriving at "let x = b in h x",
  2112 otherwise we unfold the let and arrive at g.  The simproc can be
  2113 enabled/disabled by the reference use_let_simproc.  Potential
  2114 INCOMPATIBILITY since simplification is more powerful by default.
  2115 
  2116 * Classical reasoning: the meson method now accepts theorems as arguments.
  2117 
  2118 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2119 jobs to provide advice on the provability of subgoals.
  2120 
  2121 * Theory OrderedGroup and Ring_and_Field: various additions and
  2122 improvements to faciliate calculations involving equalities and
  2123 inequalities.
  2124 
  2125 The following theorems have been eliminated or modified
  2126 (INCOMPATIBILITY):
  2127 
  2128   abs_eq             now named abs_of_nonneg
  2129   abs_of_ge_0        now named abs_of_nonneg
  2130   abs_minus_eq       now named abs_of_nonpos
  2131   imp_abs_id         now named abs_of_nonneg
  2132   imp_abs_neg_id     now named abs_of_nonpos
  2133   mult_pos           now named mult_pos_pos
  2134   mult_pos_le        now named mult_nonneg_nonneg
  2135   mult_pos_neg_le    now named mult_nonneg_nonpos
  2136   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2137   mult_neg           now named mult_neg_neg
  2138   mult_neg_le        now named mult_nonpos_nonpos
  2139 
  2140 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2141      
  2142      zero_le_square
  2143      not_square_less_zero 
  2144 
  2145   The following lemmas have been deleted from Real/RealPow:
  2146   
  2147      realpow_zero_zero
  2148      realpow_two
  2149      realpow_less
  2150      zero_le_power
  2151      realpow_two_le
  2152      abs_realpow_two
  2153      realpow_two_abs     
  2154 
  2155 * Theory Parity: added rules for simplifying exponents.
  2156 
  2157 * Theory List:
  2158 
  2159 The following theorems have been eliminated or modified
  2160 (INCOMPATIBILITY):
  2161 
  2162   list_all_Nil       now named list_all.simps(1)
  2163   list_all_Cons      now named list_all.simps(2)
  2164   list_all_conv      now named list_all_iff
  2165   set_mem_eq         now named mem_iff
  2166 
  2167 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2168 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2169 
  2170 
  2171 *** HOL-Complex ***
  2172 
  2173 * Theory RealDef: better support for embedding natural numbers and
  2174 integers in the reals.
  2175 
  2176 The following theorems have been eliminated or modified
  2177 (INCOMPATIBILITY):
  2178 
  2179   exp_ge_add_one_self  now requires no hypotheses
  2180   real_of_int_add      reversed direction of equality (use [symmetric])
  2181   real_of_int_minus    reversed direction of equality (use [symmetric])
  2182   real_of_int_diff     reversed direction of equality (use [symmetric])
  2183   real_of_int_mult     reversed direction of equality (use [symmetric])
  2184 
  2185 * Theory RComplete: expanded support for floor and ceiling functions.
  2186 
  2187 * Theory Ln is new, with properties of the natural logarithm
  2188 
  2189 * Hyperreal: There is a new type constructor "star" for making
  2190 nonstandard types.  The old type names are now type synonyms:
  2191 
  2192   hypreal = real star
  2193   hypnat = nat star
  2194   hcomplex = complex star
  2195 
  2196 * Hyperreal: Many groups of similarly-defined constants have been
  2197 replaced by polymorphic versions (INCOMPATIBILITY):
  2198 
  2199   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2200 
  2201   starset      <-- starsetNat, starsetC
  2202   *s*          <-- *sNat*, *sc*
  2203   starset_n    <-- starsetNat_n, starsetC_n
  2204   *sn*         <-- *sNatn*, *scn*
  2205   InternalSets <-- InternalNatSets, InternalCSets
  2206 
  2207   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2208   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2209   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2210   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2211   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2212 
  2213 * Hyperreal: Many type-specific theorems have been removed in favor of
  2214 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2215 
  2216   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2217   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2218   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2219   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2220   right_minus <-- hypreal_add_minus
  2221   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2222   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2223   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2224   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2225   mult_1_right <-- hcomplex_mult_one_right
  2226   mult_zero_left <-- hcomplex_mult_zero_left
  2227   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2228   right_distrib <-- hypnat_add_mult_distrib2
  2229   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2230   right_inverse <-- hypreal_mult_inverse
  2231   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2232   order_refl <-- {hypreal,hypnat}_le_refl
  2233   order_trans <-- {hypreal,hypnat}_le_trans
  2234   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2235   order_less_le <-- {hypreal,hypnat}_less_le
  2236   linorder_linear <-- {hypreal,hypnat}_le_linear
  2237   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2238   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2239   add_nonneg_nonneg <-- hypreal_le_add_order
  2240 
  2241 * Hyperreal: Separate theorems having to do with type-specific
  2242 versions of constants have been merged into theorems that apply to the
  2243 new polymorphic constants (INCOMPATIBILITY):
  2244 
  2245   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2246   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2247   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2248   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2249   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2250   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2251   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2252   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2253   STAR_diff <-- {STAR,STARC}_diff
  2254   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2255     STARC_hcomplex_of_complex}_image_subset
  2256   starset_n_Un <-- starset{Nat,C}_n_Un
  2257   starset_n_Int <-- starset{Nat,C}_n_Int
  2258   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2259   starset_n_diff <-- starset{Nat,C}_n_diff
  2260   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2261   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2262   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2263   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2264   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2265   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2266   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2267   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2268   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2269   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2270   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2271   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2272   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2273   starfun_diff <-- starfun{C,RC,CR}_diff
  2274   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2275   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2276   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2277   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2278   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2279   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2280   starfun_Id <-- starfunC_Id
  2281   starfun_approx <-- starfun{Nat,CR}_approx
  2282   starfun_capprox <-- starfun{C,RC}_capprox
  2283   starfun_abs <-- starfunNat_rabs
  2284   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2285   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2286   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2287   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2288   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2289   starfun_add_approx <-- starfunCR_add_approx
  2290   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2291   starfun_divide <-- starfun{C,CR,RC}_divide
  2292   starfun_n <-- starfun{Nat,C}_n
  2293   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2294   starfun_n_add <-- starfun{Nat,C}_n_add
  2295   starfun_n_add_minus <-- starfunNat_n_add_minus
  2296   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2297   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2298   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2299 
  2300   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2301   star_n_minus <-- {hypreal,hcomplex}_minus
  2302   star_n_diff <-- {hypreal,hcomplex}_diff
  2303   star_n_mult <-- {hypreal,hcomplex}_mult
  2304   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2305   star_n_le <-- {hypreal,hypnat}_le
  2306   star_n_less <-- {hypreal,hypnat}_less
  2307   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2308   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2309   star_n_abs <-- hypreal_hrabs
  2310   star_n_divide <-- hcomplex_divide
  2311 
  2312   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2313   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2314   star_of_diff <-- hypreal_of_real_diff
  2315   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2316   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2317   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2318   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2319   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2320   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2321   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2322   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2323   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2324   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2325   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2326   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2327   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2328   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2329   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2330   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2331   star_of_power <-- hypreal_of_real_power
  2332   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2333 
  2334 * Hyperreal: new method "transfer" that implements the transfer
  2335 principle of nonstandard analysis. With a subgoal that mentions
  2336 nonstandard types like "'a star", the command "apply transfer"
  2337 replaces it with an equivalent one that mentions only standard types.
  2338 To be successful, all free variables must have standard types; non-
  2339 standard variables must have explicit universal quantifiers.
  2340 
  2341 * Hyperreal: A theory of Taylor series.
  2342 
  2343 
  2344 *** HOLCF ***
  2345 
  2346 * Discontinued special version of 'constdefs' (which used to support
  2347 continuous functions) in favor of the general Pure one with full
  2348 type-inference.
  2349 
  2350 * New simplification procedure for solving continuity conditions; it
  2351 is much faster on terms with many nested lambda abstractions (cubic
  2352 instead of exponential time).
  2353 
  2354 * New syntax for domain package: selector names are now optional.
  2355 Parentheses should be omitted unless argument is lazy, for example:
  2356 
  2357   domain 'a stream = cons "'a" (lazy "'a stream")
  2358 
  2359 * New command 'fixrec' for defining recursive functions with pattern
  2360 matching; defining multiple functions with mutual recursion is also
  2361 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2362 sinr, or any data constructor defined by the domain package. The given
  2363 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2364 syntax and examples.
  2365 
  2366 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2367 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2368 but the proof obligation additionally includes an admissibility
  2369 requirement. The packages generate instances of class cpo or pcpo,
  2370 with continuity and strictness theorems for Rep and Abs.
  2371 
  2372 * HOLCF: Many theorems have been renamed according to a more standard naming
  2373 scheme (INCOMPATIBILITY):
  2374 
  2375   foo_inject:  "foo$x = foo$y ==> x = y"
  2376   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2377   foo_less:    "(foo$x << foo$y) = (x << y)"
  2378   foo_strict:  "foo$UU = UU"
  2379   foo_defined: "... ==> foo$x ~= UU"
  2380   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2381 
  2382 
  2383 *** ZF ***
  2384 
  2385 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2386 including the First Isomorphism Theorem (on quotienting by the kernel
  2387 of a homomorphism).
  2388 
  2389 * ZF/Simplifier: install second copy of type solver that actually
  2390 makes use of TC rules declared to Isar proof contexts (or locales);
  2391 the old version is still required for ML proof scripts.
  2392 
  2393 
  2394 *** Cube ***
  2395 
  2396 * Converted to Isar theory format; use locales instead of axiomatic
  2397 theories.
  2398 
  2399 
  2400 *** ML ***
  2401 
  2402 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2403 for ||>, ||>>, |>>,
  2404 
  2405 * Pure/library.ML no longer defines its own option datatype, but uses
  2406 that of the SML basis, which has constructors NONE and SOME instead of
  2407 None and Some, as well as exception Option.Option instead of OPTION.
  2408 The functions the, if_none, is_some, is_none have been adapted
  2409 accordingly, while Option.map replaces apsome.
  2410 
  2411 * Pure/library.ML: the exception LIST has been given up in favour of
  2412 the standard exceptions Empty and Subscript, as well as
  2413 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2414 superceded by the standard hd and tl functions etc.
  2415 
  2416 A number of basic list functions are no longer exported to the ML
  2417 toplevel, as they are variants of predefined functions.  The following
  2418 suggests how one can translate existing code:
  2419 
  2420     rev_append xs ys = List.revAppend (xs, ys)
  2421     nth_elem (i, xs) = List.nth (xs, i)
  2422     last_elem xs = List.last xs
  2423     flat xss = List.concat xss
  2424     seq fs = List.app fs
  2425     partition P xs = List.partition P xs
  2426     mapfilter f xs = List.mapPartial f xs
  2427 
  2428 * Pure/library.ML: several combinators for linear functional
  2429 transformations, notably reverse application and composition:
  2430 
  2431   x |> f                f #> g
  2432   (x, y) |-> f          f #-> g
  2433 
  2434 * Pure/library.ML: introduced/changed precedence of infix operators:
  2435 
  2436   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2437   infix 2 ?;
  2438   infix 3 o oo ooo oooo;
  2439   infix 4 ~~ upto downto;
  2440 
  2441 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2442 infix operators.
  2443 
  2444 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2445 fold_map support linear functional transformations and nesting.  For
  2446 example:
  2447 
  2448   fold f [x1, ..., xN] y =
  2449     y |> f x1 |> ... |> f xN
  2450 
  2451   (fold o fold) f [xs1, ..., xsN] y =
  2452     y |> fold f xs1 |> ... |> fold f xsN
  2453 
  2454   fold f [x1, ..., xN] =
  2455     f x1 #> ... #> f xN
  2456 
  2457   (fold o fold) f [xs1, ..., xsN] =
  2458     fold f xs1 #> ... #> fold f xsN
  2459 
  2460 * Pure/library.ML: the following selectors on type 'a option are
  2461 available:
  2462 
  2463   the:               'a option -> 'a  (*partial*)
  2464   these:             'a option -> 'a  where 'a = 'b list
  2465   the_default: 'a -> 'a option -> 'a
  2466   the_list:          'a option -> 'a list
  2467 
  2468 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2469 basic operations for association lists, following natural argument
  2470 order; moreover the explicit equality predicate passed here avoids
  2471 potentially expensive polymorphic runtime equality checks.
  2472 The old functions may be expressed as follows:
  2473 
  2474   assoc = uncurry (AList.lookup (op =))
  2475   assocs = these oo AList.lookup (op =)
  2476   overwrite = uncurry (AList.update (op =)) o swap
  2477 
  2478 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2479 
  2480   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2481   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2482 
  2483 replacing make_keylist and keyfilter (occassionally used)
  2484 Naive rewrites:
  2485 
  2486   make_keylist = AList.make
  2487   keyfilter = AList.find (op =)
  2488 
  2489 * eq_fst and eq_snd now take explicit equality parameter, thus
  2490   avoiding eqtypes. Naive rewrites:
  2491 
  2492     eq_fst = eq_fst (op =)
  2493     eq_snd = eq_snd (op =)
  2494 
  2495 * Removed deprecated apl and apr (rarely used).
  2496   Naive rewrites:
  2497 
  2498     apl (n, op) =>>= curry op n
  2499     apr (op, m) =>>= fn n => op (n, m)
  2500 
  2501 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2502 provides a reasonably efficient light-weight implementation of sets as
  2503 lists.
  2504 
  2505 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2506 few new operations; existing lookup and update are now curried to
  2507 follow natural argument order (for use with fold etc.);
  2508 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2509 
  2510 * Pure/General: output via the Isabelle channels of
  2511 writeln/warning/error etc. is now passed through Output.output, with a
  2512 hook for arbitrary transformations depending on the print_mode
  2513 (cf. Output.add_mode -- the first active mode that provides a output
  2514 function wins).  Already formatted output may be embedded into further
  2515 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2516 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2517 accommodate easy composition of diagnostic messages etc.  Programmers
  2518 rarely need to care about Output.output or Output.raw at all, with
  2519 some notable exceptions: Output.output is required when bypassing the
  2520 standard channels (writeln etc.), or in token translations to produce
  2521 properly formatted results; Output.raw is required when capturing
  2522 already output material that will eventually be presented to the user
  2523 a second time.  For the default print mode, both Output.output and
  2524 Output.raw have no effect.
  2525 
  2526 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2527 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2528 cumulative results are displayed at the end of a batch session.
  2529 
  2530 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2531 replaced by File.platform_path and File.shell_path (with appropriate
  2532 hooks).  This provides a clean interface for unusual systems where the
  2533 internal and external process view of file names are different.
  2534 
  2535 * Pure: more efficient orders for basic syntactic entities: added
  2536 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2537 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2538 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2539 orders now -- potential INCOMPATIBILITY for code that depends on a
  2540 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2541 Library.sort_strings on result).
  2542 
  2543 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2544 fold_types traverse types/terms from left to right, observing natural
  2545 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2546 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2547 
  2548 * Pure: name spaces have been refined, with significant changes of the
  2549 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2550 to extern(_table).  The plain name entry path is superceded by a
  2551 general 'naming' context, which also includes the 'policy' to produce
  2552 a fully qualified name and external accesses of a fully qualified
  2553 name; NameSpace.extend is superceded by context dependent
  2554 Sign.declare_name.  Several theory and proof context operations modify
  2555 the naming context.  Especially note Theory.restore_naming and
  2556 ProofContext.restore_naming to get back to a sane state; note that
  2557 Theory.add_path is no longer sufficient to recover from
  2558 Theory.absolute_path in particular.
  2559 
  2560 * Pure: new flags short_names (default false) and unique_names
  2561 (default true) for controlling output of qualified names.  If
  2562 short_names is set, names are printed unqualified.  If unique_names is
  2563 reset, the name prefix is reduced to the minimum required to achieve
  2564 the original result when interning again, even if there is an overlap
  2565 with earlier declarations.
  2566 
  2567 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2568 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2569 (useful for printing error messages).  INCOMPATIBILITY.
  2570 
  2571 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2572 Theory.theory are now identified, referring to the universal
  2573 Context.theory (see Pure/context.ML).  Actual signature and theory
  2574 content is managed as theory data.  The old code and interfaces were
  2575 spread over many files and structures; the new arrangement introduces
  2576 considerable INCOMPATIBILITY to gain more clarity:
  2577 
  2578   Context -- theory management operations (name, identity, inclusion,
  2579     parents, ancestors, merge, etc.), plus generic theory data;
  2580 
  2581   Sign -- logical signature and syntax operations (declaring consts,
  2582     types, etc.), plus certify/read for common entities;
  2583 
  2584   Theory -- logical theory operations (stating axioms, definitions,
  2585     oracles), plus a copy of logical signature operations (consts,
  2586     types, etc.); also a few basic management operations (Theory.copy,
  2587     Theory.merge, etc.)
  2588 
  2589 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2590 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2591 for convenience -- they merely return the theory.
  2592 
  2593 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2594 
  2595 * Pure: the Isar proof context type is already defined early in Pure
  2596 as Context.proof (note that ProofContext.context and Proof.context are
  2597 aliases, where the latter is the preferred name).  This enables other
  2598 Isabelle components to refer to that type even before Isar is present.
  2599 
  2600 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2601 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2602 any of these kinds.  For example, Sign.intern typeK is now
  2603 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2604 Theory.hide_types.  Also note that former
  2605 Theory.hide_classes/types/consts are now
  2606 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2607 internalize their arguments!  INCOMPATIBILITY.
  2608 
  2609 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2610 datatype thmref (with constructors Name and NameSelection) instead of
  2611 plain string -- INCOMPATIBILITY;
  2612 
  2613 * Pure: cases produced by proof methods specify options, where NONE
  2614 means to remove case bindings -- INCOMPATIBILITY in
  2615 (RAW_)METHOD_CASES.
  2616 
  2617 * Pure: the following operations retrieve axioms or theorems from a
  2618 theory node or theory hierarchy, respectively:
  2619 
  2620   Theory.axioms_of: theory -> (string * term) list
  2621   Theory.all_axioms_of: theory -> (string * term) list
  2622   PureThy.thms_of: theory -> (string * thm) list
  2623   PureThy.all_thms_of: theory -> (string * thm) list
  2624 
  2625 * Pure: print_tac now outputs the goal through the trace channel.
  2626 
  2627 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2628 Reference Toplevel.debug (default false) controls detailed printing
  2629 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2630 controls execution profiling -- set to 1 for time and 2 for space
  2631 (both increase the runtime).
  2632 
  2633 * Isar session: The initial use of ROOT.ML is now always timed,
  2634 i.e. the log will show the actual process times, in contrast to the
  2635 elapsed wall-clock time that the outer shell wrapper produces.
  2636 
  2637 * Simplifier: improved handling of bound variables (nameless
  2638 representation, avoid allocating new strings).  Simprocs that invoke
  2639 the Simplifier recursively should use Simplifier.inherit_bounds to
  2640 avoid local name clashes.  Failure to do so produces warnings
  2641 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2642 for further details.
  2643 
  2644 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2645 bindings for all theorems stored within a given theory; this may help
  2646 in porting non-Isar theories to Isar ones, while keeping ML proof
  2647 scripts for the time being.
  2648 
  2649 * ML operator HTML.with_charset specifies the charset begin used for
  2650 generated HTML files.  For example:
  2651 
  2652   HTML.with_charset "utf-8" use_thy "Hebrew";
  2653   HTML.with_charset "utf-8" use_thy "Chinese";
  2654 
  2655 
  2656 *** System ***
  2657 
  2658 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2659 isabelle, isatool etc.).
  2660 
  2661 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2662 isatool doc, isatool mkdir, display_drafts etc.).
  2663 
  2664 * isatool usedir: option -f allows specification of the ML file to be
  2665 used by Isabelle; default is ROOT.ML.
  2666 
  2667 * New isatool version outputs the version identifier of the Isabelle
  2668 distribution being used.
  2669 
  2670 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2671 (containing Boolean satisfiability problems) into Isabelle/HOL
  2672 theories.
  2673 
  2674 
  2675 
  2676 New in Isabelle2004 (April 2004)
  2677 --------------------------------
  2678 
  2679 *** General ***
  2680 
  2681 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2682   Replaces linorder.ML.
  2683 
  2684 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2685   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2686   (\<a>...\<z>), are now considered normal letters, and can therefore
  2687   be used anywhere where an ASCII letter (a...zA...Z) has until
  2688   now. COMPATIBILITY: This obviously changes the parsing of some
  2689   terms, especially where a symbol has been used as a binder, say
  2690   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2691   as an identifier.  Fix it by inserting a space around former
  2692   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2693   existing theory and ML files.
  2694 
  2695 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2696 
  2697 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2698   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2699   a normal (but invisible) letter. For multiple letter subscripts repeat
  2700   \<^isub> like this: x\<^isub>1\<^isub>2.
  2701 
  2702 * Pure: There are now sub-/superscripts that can span more than one
  2703   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2704   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2705   superscript. The new control characters are not identifier parts.
  2706 
  2707 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2708   content of "..." to the latex file instead of \isacntrl... . The "..."
  2709   may consist of any printable characters excluding the end bracket >.
  2710 
  2711 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2712   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2713   declare constants "final", which prevents their being given a definition
  2714   later.  It is useful for constants whose behaviour is fixed axiomatically
  2715   rather than definitionally, such as the meta-logic connectives.
  2716 
  2717 * Pure: 'instance' now handles general arities with general sorts
  2718   (i.e. intersections of classes),
  2719 
  2720 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2721   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2722   It can be changed to alter the colors/layout of generated pages.
  2723 
  2724 
  2725 *** Isar ***
  2726 
  2727 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2728   cut_tac, subgoal_tac and thin_tac:
  2729   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2730     locales are no longer forced to write Isar proof scripts.
  2731     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2732     emulations.
  2733   - INCOMPATIBILITY: names of variables to be instantiated may no
  2734     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2735     This is consistent with the instantiation attribute "where".
  2736 
  2737 * Attributes "where" and "of":
  2738   - Now take type variables of instantiated theorem into account when reading
  2739     the instantiation string.  This fixes a bug that caused instantiated
  2740     theorems to have too special types in some circumstances.
  2741   - "where" permits explicit instantiations of type variables.
  2742 
  2743 * Calculation commands "moreover" and "also" no longer interfere with
  2744   current facts ("this"), admitting arbitrary combinations with "then"
  2745   and derived forms.
  2746 
  2747 * Locales:
  2748   - Goal statements involving the context element "includes" no longer
  2749     generate theorems with internal delta predicates (those ending on
  2750     "_axioms") in the premise.
  2751     Resolve particular premise with <locale>.intro to obtain old form.
  2752   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2753     specification and "includes" elements in goal statement.
  2754   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2755     [intro?] and [elim?] (respectively) by default.
  2756   - Experimental command for instantiation of locales in proof contexts:
  2757         instantiate <label>[<attrs>]: <loc>
  2758     Instantiates locale <loc> and adds all its theorems to the current context
  2759     taking into account their attributes.  Label and attrs are optional
  2760     modifiers, like in theorem declarations.  If present, names of
  2761     instantiated theorems are qualified with <label>, and the attributes
  2762     <attrs> are applied after any attributes these theorems might have already.
  2763       If the locale has assumptions, a chained fact of the form
  2764     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2765     are derived.  The command does not support old-style locales declared
  2766     with "locale (open)".
  2767       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2768 
  2769 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2770   (Isar) contexts.
  2771 
  2772 
  2773 *** HOL ***
  2774 
  2775 * Proof import: new image HOL4 contains the imported library from
  2776   the HOL4 system with about 2500 theorems. It is imported by
  2777   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2778   can be used like any other Isabelle image.  See
  2779   HOL/Import/HOL/README for more information.
  2780 
  2781 * Simplifier:
  2782   - Much improved handling of linear and partial orders.
  2783     Reasoners for linear and partial orders are set up for type classes
  2784     "linorder" and "order" respectively, and are added to the default simpset
  2785     as solvers.  This means that the simplifier can build transitivity chains
  2786     to solve goals from the assumptions.
  2787   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2788     of blast or auto after simplification become unnecessary because the goal
  2789     is solved by simplification already.
  2790 
  2791 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2792     all proved in axiomatic type classes for semirings, rings and fields.
  2793 
  2794 * Numerics:
  2795   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2796     now formalized using the Ring_and_Field theory mentioned above.
  2797   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2798     than before, because now they are set up once in a generic manner.
  2799   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2800     Look for the general versions in Ring_and_Field (and Power if they concern
  2801     exponentiation).
  2802 
  2803 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2804 
  2805 * Records:
  2806   - Record types are now by default printed with their type abbreviation
  2807     instead of the list of all field types. This can be configured via
  2808     the reference "print_record_type_abbr".
  2809   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2810     (not enabled by default).
  2811   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2812     EX x. x = sel r to True (not enabled by default).
  2813   - Tactic "record_split_simp_tac" to split and simplify records added.
  2814 
  2815 * 'specification' command added, allowing for definition by
  2816   specification.  There is also an 'ax_specification' command that
  2817   introduces the new constants axiomatically.
  2818 
  2819 * arith(_tac) is now able to generate counterexamples for reals as well.
  2820 
  2821 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2822 
  2823 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2824   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2825 
  2826 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2827   matrix theory to linear programming.
  2828 
  2829 * Unions and Intersections:
  2830   The latex output syntax of UN and INT has been changed
  2831   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2832   i.e. the index formulae has become a subscript.
  2833   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2834 
  2835 * Unions and Intersections over Intervals:
  2836   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2837   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2838   like in normal math, and corresponding versions for < and for intersection.
  2839 
  2840 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2841   lexicographic dictonary ordering has been added as "lexord".
  2842 
  2843 * ML: the legacy theory structures Int and List have been removed. They had
  2844   conflicted with ML Basis Library structures having the same names.
  2845 
  2846 * 'refute' command added to search for (finite) countermodels.  Only works
  2847   for a fragment of HOL.  The installation of an external SAT solver is
  2848   highly recommended.  See "HOL/Refute.thy" for details.
  2849 
  2850 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2851   formulae under an assignment of free variables to random values.
  2852   In contrast to 'refute', it can deal with inductive datatypes,
  2853   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2854   for examples.
  2855 
  2856 
  2857 *** HOLCF ***
  2858 
  2859 * Streams now come with concatenation and are part of the HOLCF image
  2860 
  2861 
  2862 
  2863 New in Isabelle2003 (May 2003)
  2864 ------------------------------
  2865 
  2866 *** General ***
  2867 
  2868 * Provers/simplifier:
  2869 
  2870   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2871     Assumptions are now subject to complete mutual simplification,
  2872     not just from left to right. The simplifier now preserves
  2873     the order of assumptions.
  2874 
  2875     Potential INCOMPATIBILITY:
  2876 
  2877     -- simp sometimes diverges where the old version did
  2878        not, e.g. invoking simp on the goal
  2879 
  2880         [| P (f x); y = x; f x = f y |] ==> Q
  2881 
  2882        now gives rise to the infinite reduction sequence
  2883 
  2884         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2885 
  2886        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2887        kind of problem.
  2888 
  2889     -- Tactics combining classical reasoner and simplification (such as auto)
  2890        are also affected by this change, because many of them rely on
  2891        simp. They may sometimes diverge as well or yield a different numbers
  2892        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2893        in case of problems. Sometimes subsequent calls to the classical
  2894        reasoner will fail because a preceeding call to the simplifier too
  2895        eagerly simplified the goal, e.g. deleted redundant premises.
  2896 
  2897   - The simplifier trace now shows the names of the applied rewrite rules
  2898 
  2899   - You can limit the number of recursive invocations of the simplifier
  2900     during conditional rewriting (where the simplifie tries to solve the
  2901     conditions before applying the rewrite rule):
  2902     ML "simp_depth_limit := n"
  2903     where n is an integer. Thus you can force termination where previously
  2904     the simplifier would diverge.
  2905 
  2906   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2907 
  2908   - No longer aborts on failed congruence proof.  Instead, the
  2909     congruence is ignored.
  2910 
  2911 * Pure: New generic framework for extracting programs from constructive
  2912   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2913   as HOL/Extraction for some case studies.
  2914 
  2915 * Pure: The main goal of the proof state is no longer shown by default, only
  2916 the subgoals. This behaviour is controlled by a new flag.
  2917    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2918 (ML: Proof.show_main_goal).
  2919 
  2920 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2921 rules whose conclusion matches subgoal 1:
  2922       PG menu: Isabelle/Isar -> Show me -> matching rules
  2923 The rules are ordered by how closely they match the subgoal.
  2924 In particular, rules that solve a subgoal outright are displayed first
  2925 (or rather last, the way they are printed).
  2926 (ML: ProofGeneral.print_intros())
  2927 
  2928 * Pure: New flag trace_unify_fail causes unification to print
  2929 diagnostic information (PG: in trace buffer) when it fails. This is
  2930 useful for figuring out why single step proofs like rule, erule or
  2931 assumption failed.
  2932 
  2933 * Pure: Locale specifications now produce predicate definitions
  2934 according to the body of text (covering assumptions modulo local
  2935 definitions); predicate "loc_axioms" covers newly introduced text,
  2936 while "loc" is cumulative wrt. all included locale expressions; the
  2937 latter view is presented only on export into the global theory
  2938 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2939 on the old view without predicates;
  2940 
  2941 * Pure: predefined locales "var" and "struct" are useful for sharing
  2942 parameters (as in CASL, for example); just specify something like
  2943 ``var x + var y + struct M'' as import;
  2944 
  2945 * Pure: improved thms_containing: proper indexing of facts instead of
  2946 raw theorems; check validity of results wrt. current name space;
  2947 include local facts of proof configuration (also covers active
  2948 locales), cover fixed variables in index; may use "_" in term
  2949 specification; an optional limit for the number of printed facts may
  2950 be given (the default is 40);
  2951 
  2952 * Pure: disallow duplicate fact bindings within new-style theory files
  2953 (batch-mode only);
  2954 
  2955 * Provers: improved induct method: assumptions introduced by case
  2956 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2957 the goal statement); "foo" still refers to all facts collectively;
  2958 
  2959 * Provers: the function blast.overloaded has been removed: all constants
  2960 are regarded as potentially overloaded, which improves robustness in exchange
  2961 for slight decrease in efficiency;
  2962 
  2963 * Provers/linorder: New generic prover for transitivity reasoning over
  2964 linear orders.  Note: this prover is not efficient!
  2965 
  2966 * Isar: preview of problems to finish 'show' now produce an error
  2967 rather than just a warning (in interactive mode);
  2968 
  2969 
  2970 *** HOL ***
  2971 
  2972 * arith(_tac)
  2973 
  2974  - Produces a counter example if it cannot prove a goal.
  2975    Note that the counter example may be spurious if the goal is not a formula
  2976    of quantifier-free linear arithmetic.
  2977    In ProofGeneral the counter example appears in the trace buffer.
  2978 
  2979  - Knows about div k and mod k where k is a numeral of type nat or int.
  2980 
  2981  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2982    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2983    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2984 
  2985 * simp's arithmetic capabilities have been enhanced a bit: it now
  2986 takes ~= in premises into account (by performing a case split);
  2987 
  2988 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2989 are distributed over a sum of terms;
  2990 
  2991 * New tactic "trans_tac" and method "trans" instantiate
  2992 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2993 "<=", "<" and "=").
  2994 
  2995 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2996 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2997 
  2998 * 'typedef' command has new option "open" to suppress the set
  2999 definition;
  3000 
  3001 * functions Min and Max on finite sets have been introduced (theory
  3002 Finite_Set);
  3003 
  3004 * attribute [symmetric] now works for relations as well; it turns
  3005 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3006 
  3007 * induct over a !!-quantified statement (say !!x1..xn):
  3008   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3009 
  3010 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3011 %x. None. Warning: empty_def now refers to the previously hidden definition
  3012 of the empty set.
  3013 
  3014 * Algebra: formalization of classical algebra.  Intended as base for
  3015 any algebraic development in Isabelle.  Currently covers group theory
  3016 (up to Sylow's theorem) and ring theory (Universal Property of
  3017 Univariate Polynomials).  Contributions welcome;
  3018 
  3019 * GroupTheory: deleted, since its material has been moved to Algebra;
  3020 
  3021 * Complex: new directory of the complex numbers with numeric constants,
  3022 nonstandard complex numbers, and some complex analysis, standard and
  3023 nonstandard (Jacques Fleuriot);
  3024 
  3025 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3026 
  3027 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3028 Fleuriot);
  3029 
  3030 * Real/HahnBanach: updated and adapted to locales;
  3031 
  3032 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3033 Gray and Kramer);
  3034 
  3035 * UNITY: added the Meier-Sanders theory of progress sets;
  3036 
  3037 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3038 as abstract algorithms, instantiated to the JVM;
  3039 
  3040 * Bali: Java source language formalization. Type system, operational
  3041 semantics, axiomatic semantics. Supported language features:
  3042 classes, interfaces, objects,virtual methods, static methods,
  3043 static/instance fields, arrays, access modifiers, definite
  3044 assignment, exceptions.
  3045 
  3046 
  3047 *** ZF ***
  3048 
  3049 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3050 universe, etc.);
  3051 
  3052 * Main ZF: virtually all theories converted to new-style format;
  3053 
  3054 
  3055 *** ML ***
  3056 
  3057 * Pure: Tactic.prove provides sane interface for internal proofs;
  3058 omits the infamous "standard" operation, so this is more appropriate
  3059 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3060 
  3061 * Pure: improved error reporting of simprocs;
  3062 
  3063 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3064 up simprocs;
  3065 
  3066 
  3067 *** Document preparation ***
  3068 
  3069 * uses \par instead of \\ for line breaks in theory text. This may
  3070 shift some page breaks in large documents. To get the old behaviour
  3071 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3072 
  3073 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3074 other packages
  3075 
  3076 * \<euro> now needs package babel/greek instead of marvosym (which
  3077 broke \Rightarrow)
  3078 
  3079 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3080 textcomp package)
  3081 
  3082 
  3083 
  3084 New in Isabelle2002 (March 2002)
  3085 --------------------------------
  3086 
  3087 *** Document preparation ***
  3088 
  3089 * greatly simplified document preparation setup, including more
  3090 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3091 instructive isatool mkdir; users should basically be able to get
  3092 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3093 users may run a separate document processing stage manually like this:
  3094 "isatool usedir -D output HOL Test && isatool document Test/output";
  3095 
  3096 * theory dependency graph may now be incorporated into documents;
  3097 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3098 with \includegraphics of LaTeX;
  3099 
  3100 * proper spacing of consecutive markup elements, especially text
  3101 blocks after section headings;
  3102 
  3103 * support bold style (for single symbols only), input syntax is like
  3104 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3105 
  3106 * \<bullet> is now output as bold \cdot by default, which looks much
  3107 better in printed text;
  3108 
  3109 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3110 note that these symbols are currently unavailable in Proof General /
  3111 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3112 
  3113 * isatool latex no longer depends on changed TEXINPUTS, instead
  3114 isatool document copies the Isabelle style files to the target
  3115 location;
  3116 
  3117 
  3118 *** Isar ***
  3119 
  3120 * Pure/Provers: improved proof by cases and induction;
  3121   - 'case' command admits impromptu naming of parameters (such as
  3122     "case (Suc n)");
  3123   - 'induct' method divinates rule instantiation from the inductive
  3124     claim; no longer requires excessive ?P bindings for proper
  3125     instantiation of cases;
  3126   - 'induct' method properly enumerates all possibilities of set/type
  3127     rules; as a consequence facts may be also passed through *type*
  3128     rules without further ado;
  3129   - 'induct' method now derives symbolic cases from the *rulified*
  3130     rule (before it used to rulify cases stemming from the internal
  3131     atomized version); this means that the context of a non-atomic
  3132     statement becomes is included in the hypothesis, avoiding the
  3133     slightly cumbersome show "PROP ?case" form;
  3134   - 'induct' may now use elim-style induction rules without chaining
  3135     facts, using ``missing'' premises from the goal state; this allows
  3136     rules stemming from inductive sets to be applied in unstructured
  3137     scripts, while still benefitting from proper handling of non-atomic
  3138     statements; NB: major inductive premises need to be put first, all
  3139     the rest of the goal is passed through the induction;
  3140   - 'induct' proper support for mutual induction involving non-atomic
  3141     rule statements (uses the new concept of simultaneous goals, see
  3142     below);
  3143   - append all possible rule selections, but only use the first
  3144     success (no backtracking);
  3145   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3146   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3147   - added 'print_induct_rules' (covered by help item in recent Proof
  3148     General versions);
  3149   - moved induct/cases attributes to Pure, methods to Provers;
  3150   - generic method setup instantiated for FOL and HOL;
  3151 
  3152 * Pure: support multiple simultaneous goal statements, for example
  3153 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3154 meta-level mechanism, this acts as if several individual goals had
  3155 been stated separately; in particular common proof methods need to be
  3156 repeated in order to cover all claims; note that a single elimination
  3157 step is *not* sufficient to establish the two conjunctions, so this
  3158 fails:
  3159 
  3160   assume "A & B" then have A and B ..   (*".." fails*)
  3161 
  3162 better use "obtain" in situations as above; alternative refer to
  3163 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3164 
  3165 * Pure: proper integration with ``locales''; unlike the original
  3166 version by Florian Kammller, Isar locales package high-level proof
  3167 contexts rather than raw logical ones (e.g. we admit to include
  3168 attributes everywhere); operations on locales include merge and
  3169 rename; support for implicit arguments (``structures''); simultaneous
  3170 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3171 some examples;
  3172 
  3173 * Pure: the following commands have been ``localized'', supporting a
  3174 target locale specification "(in name)": 'lemma', 'theorem',
  3175 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3176 stored both within the locale and at the theory level (exported and
  3177 qualified by the locale name);
  3178 
  3179 * Pure: theory goals may now be specified in ``long'' form, with
  3180 ad-hoc contexts consisting of arbitrary locale elements. for example
  3181 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3182 definitions may be given, too); the result is a meta-level rule with
  3183 the context elements being discharged in the obvious way;
  3184 
  3185 * Pure: new proof command 'using' allows to augment currently used
  3186 facts after a goal statement ('using' is syntactically analogous to
  3187 'apply', but acts on the goal's facts only); this allows chained facts
  3188 to be separated into parts given before and after a claim, as in
  3189 ``from a and b have C using d and e <proof>'';
  3190 
  3191 * Pure: renamed "antecedent" case to "rule_context";
  3192 
  3193 * Pure: new 'judgment' command records explicit information about the
  3194 object-logic embedding (used by several tools internally); no longer
  3195 use hard-wired "Trueprop";
  3196 
  3197 * Pure: added 'corollary' command;
  3198 
  3199 * Pure: fixed 'token_translation' command;
  3200 
  3201 * Pure: removed obsolete 'exported' attribute;
  3202 
  3203 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3204 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3205 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3206 
  3207 * Pure: method 'atomize' presents local goal premises as object-level
  3208 statements (atomic meta-level propositions); setup controlled via
  3209 rewrite rules declarations of 'atomize' attribute; example
  3210 application: 'induct' method with proper rule statements in improper
  3211 proof *scripts*;
  3212 
  3213 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3214 now consider the syntactic context of assumptions, giving a better
  3215 chance to get type-inference of the arguments right (this is
  3216 especially important for locales);
  3217 
  3218 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3219 mode;
  3220 
  3221 * Pure/obtain: the formal conclusion "thesis", being marked as
  3222 ``internal'', may no longer be reference directly in the text;
  3223 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3224 situations;
  3225 
  3226 * Pure: generic 'sym' attribute which declares a rule both as pure
  3227 'elim?' and for the 'symmetric' operation;
  3228 
  3229 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3230 text; the fixed correlation with particular command syntax has been
  3231 discontinued;
  3232 
  3233 * Pure: new method 'rules' is particularly well-suited for proof
  3234 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3235 but often produces more compact proof terms with less detours;
  3236 
  3237 * Pure/Provers/classical: simplified integration with pure rule
  3238 attributes and methods; the classical "intro?/elim?/dest?"
  3239 declarations coincide with the pure ones; the "rule" method no longer
  3240 includes classically swapped intros; "intro" and "elim" methods no
  3241 longer pick rules from the context; also got rid of ML declarations
  3242 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3243 INCOMPATIBILITY;
  3244 
  3245 * Provers/classical: attribute 'swapped' produces classical inversions
  3246 of introduction rules;
  3247 
  3248 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3249 rules instead of full simplifier context; 'iff' attribute handles
  3250 conditional rules;
  3251 
  3252 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3253 
  3254 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3255 "(permissive)" option to recover old behavior;
  3256 
  3257 * HOL: 'inductive' no longer features separate (collective) attributes
  3258 for 'intros' (was found too confusing);
  3259 
  3260 * HOL: properly declared induction rules less_induct and
  3261 wf_induct_rule;
  3262 
  3263 
  3264 *** HOL ***
  3265 
  3266 * HOL: moved over to sane numeral syntax; the new policy is as
  3267 follows:
  3268 
  3269   - 0 and 1 are polymorphic constants, which are defined on any
  3270   numeric type (nat, int, real etc.);
  3271 
  3272   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3273   binary representation internally;
  3274 
  3275   - type nat has special constructor Suc, and generally prefers Suc 0
  3276   over 1::nat and Suc (Suc 0) over 2::nat;
  3277 
  3278 This change may cause significant problems of INCOMPATIBILITY; here
  3279 are some hints on converting existing sources:
  3280 
  3281   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3282   entities, so expressions involving "-" (unary or binary minus) need
  3283   to be spaced properly;
  3284 
  3285   - existing occurrences of "1" may need to be constraint "1::nat" or
  3286   even replaced by Suc 0; similar for old "2";
  3287 
  3288   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3289 
  3290   - remove all special provisions on numerals in proofs;
  3291 
  3292 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3293 representation (depends on bin_arith_simps in the default context);
  3294 
  3295 * HOL: symbolic syntax for x^2 (numeral 2);
  3296 
  3297 * HOL: the class of all HOL types is now called "type" rather than
  3298 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3299 in axclass/classes, instance/arities, and (usually rare) occurrences
  3300 in typings (of consts etc.); internally the class is called
  3301 "HOL.type", ML programs should refer to HOLogic.typeS;
  3302 
  3303 * HOL/record package improvements:
  3304   - new derived operations "fields" to build a partial record section,
  3305     "extend" to promote a fixed record to a record scheme, and
  3306     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3307     declared as simp by default;
  3308   - shared operations ("more", "fields", etc.) now need to be always
  3309     qualified) --- potential INCOMPATIBILITY;
  3310   - removed "make_scheme" operations (use "make" with "extend") --
  3311     INCOMPATIBILITY;
  3312   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3313   - provides cases/induct rules for use with corresponding Isar
  3314     methods (for concrete records, record schemes, concrete more
  3315     parts, and schematic more parts -- in that order);
  3316   - internal definitions directly based on a light-weight abstract
  3317     theory of product types over typedef rather than datatype;
  3318 
  3319 * HOL: generic code generator for generating executable ML code from
  3320 specifications; specific support for HOL constructs such as inductive
  3321 datatypes and sets, as well as recursive functions; can be invoked
  3322 via 'generate_code' theory section;
  3323 
  3324 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3325 
  3326 * HOL: consolidated and renamed several theories.  In particular:
  3327         Ord.thy has been absorbed into HOL.thy
  3328         String.thy has been absorbed into List.thy
  3329 
  3330 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3331 (beware of argument permutation!);
  3332 
  3333 * HOL: linorder_less_split superseded by linorder_cases;
  3334 
  3335 * HOL/List: "nodups" renamed to "distinct";
  3336 
  3337 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3338 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3339   - Ex_def has changed, now need to use some_eq_ex
  3340 
  3341 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3342 in this (rare) case use:
  3343 
  3344   delSWrapper "split_all_tac"
  3345   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3346 
  3347 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3348 MAY FAIL;
  3349 
  3350 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3351 Isabelle's type classes, ^ on functions and relations has too general
  3352 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3353 necessary to attach explicit type constraints;
  3354 
  3355 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3356 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3357 renamed accordingly (eg "compI" -> "rel_compI").
  3358 
  3359 * HOL: syntax translations now work properly with numerals and records
  3360 expressions;
  3361 
  3362 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3363 of "lam" -- INCOMPATIBILITY;
  3364 
  3365 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3366 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3367 renamed "Product_Type.unit";
  3368 
  3369 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3370 
  3371 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3372 the "cases" method);
  3373 
  3374 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3375 Florian Kammller);
  3376 
  3377 * HOL/IMP: updated and converted to new-style theory format; several
  3378 parts turned into readable document, with proper Isar proof texts and
  3379 some explanations (by Gerwin Klein);
  3380 
  3381 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3382 
  3383 * HOL-Hyperreal is now a logic image;
  3384 
  3385 
  3386 *** HOLCF ***
  3387 
  3388 * Isar: consts/constdefs supports mixfix syntax for continuous
  3389 operations;
  3390 
  3391 * Isar: domain package adapted to new-style theory format, e.g. see
  3392 HOLCF/ex/Dnat.thy;
  3393 
  3394 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3395 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3396 lift.induct_tac, always use UU instead of Undef;
  3397 
  3398 * HOLCF/IMP: updated and converted to new-style theory;
  3399 
  3400 
  3401 *** ZF ***
  3402 
  3403 * Isar: proper integration of logic-specific tools and packages,
  3404 including theory commands '(co)inductive', '(co)datatype',
  3405 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3406 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3407 
  3408 * theory Main no longer includes AC; for the Axiom of Choice, base
  3409 your theory on Main_ZFC;
  3410 
  3411 * the integer library now covers quotients and remainders, with many
  3412 laws relating division to addition, multiplication, etc.;
  3413 
  3414 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3415 typeless version of the formalism;
  3416 
  3417 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3418 format;
  3419 
  3420 * ZF/Induct: new directory for examples of inductive definitions,
  3421 including theory Multiset for multiset orderings; converted to
  3422 new-style theory format;
  3423 
  3424 * ZF: many new theorems about lists, ordinals, etc.;
  3425 
  3426 
  3427 *** General ***
  3428 
  3429 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3430 variable proof controls level of detail: 0 = no proofs (only oracle
  3431 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3432 also ref manual for further ML interfaces;
  3433 
  3434 * Pure/axclass: removed obsolete ML interface
  3435 goal_subclass/goal_arity;
  3436 
  3437 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3438 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3439 separate tokens, so expressions involving minus need to be spaced
  3440 properly;
  3441 
  3442 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3443 rather than "infixl" or "infixr";
  3444 
  3445 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3446 sort constraint specifications in type inference; e.g. "x::_::foo"
  3447 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3448 type variable);
  3449 
  3450 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3451 control output of nested => (types); the default behavior is
  3452 "type_brackets";
  3453 
  3454 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3455 tokens into AST constants;
  3456 
  3457 * Pure/syntax: prefer later declarations of translations and print
  3458 translation functions; potential INCOMPATIBILITY: need to reverse
  3459 multiple declarations for same syntax element constant;
  3460 
  3461 * Pure/show_hyps reset by default (in accordance to existing Isar
  3462 practice);
  3463 
  3464 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3465 addSafter;
  3466 
  3467 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3468 as well;
  3469 
  3470 * system: tested support for MacOS X; should be able to get Isabelle +
  3471 Proof General to work in a plain Terminal after installing Poly/ML
  3472 (e.g. from the Isabelle distribution area) and GNU bash alone
  3473 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3474 support requires further installations, e.g. from
  3475 http://fink.sourceforge.net/);
  3476 
  3477 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3478 
  3479 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3480 of 40 MB), cf. ML_OPTIONS;
  3481 
  3482 * system: Proof General keywords specification is now part of the
  3483 Isabelle distribution (see etc/isar-keywords.el);
  3484 
  3485 * system: support for persistent Proof General sessions (refrain from
  3486 outdating all loaded theories on startup); user may create writable
  3487 logic images like this: ``isabelle -q HOL Test'';
  3488 
  3489 * system: smart selection of Isabelle process versus Isabelle
  3490 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3491 run both "isabelle" and "Isabelle" even if file names are badly
  3492 damaged (executable inspects the case of the first letter of its own
  3493 name); added separate "isabelle-process" and "isabelle-interface";
  3494 
  3495 * system: refrain from any attempt at filtering input streams; no
  3496 longer support ``8bit'' encoding of old isabelle font, instead proper
  3497 iso-latin characters may now be used; the related isatools
  3498 "symbolinput" and "nonascii" have disappeared as well;
  3499 
  3500 * system: removed old "xterm" interface (the print modes "xterm" and
  3501 "xterm_color" are still available for direct use in a suitable
  3502 terminal);
  3503 
  3504 
  3505 
  3506 New in Isabelle99-2 (February 2001)
  3507 -----------------------------------
  3508 
  3509 *** Overview of INCOMPATIBILITIES ***
  3510 
  3511 * HOL: please note that theories in the Library and elsewhere often use the
  3512 new-style (Isar) format; to refer to their theorems in an ML script you must
  3513 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3514 
  3515 * HOL: inductive package no longer splits induction rule aggressively,
  3516 but only as far as specified by the introductions given; the old
  3517 format may be recovered via ML function complete_split_rule or attribute
  3518 'split_rule (complete)';
  3519 
  3520 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3521 gfp_Tarski to gfp_unfold;
  3522 
  3523 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3524 
  3525 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3526 relation); infix "^^" has been renamed "``"; infix "``" has been
  3527 renamed "`"; "univalent" has been renamed "single_valued";
  3528 
  3529 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3530 operation;
  3531 
  3532 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3533 
  3534 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3535 
  3536 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3537 consequence, it is no longer monotonic wrt. the local goal context
  3538 (which is now passed through the inductive cases);
  3539 
  3540 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3541 \<gg> to \<ggreater>;
  3542 
  3543 
  3544 *** Document preparation ***
  3545 
  3546 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3547 available: are "it" for near math-mode best-style output, "sl" for
  3548 slanted text style, and "tt" for plain type-writer; if no
  3549 \isabellestyle command is given, output is according to slanted
  3550 type-writer);
  3551 
  3552 * support sub/super scripts (for single symbols only), input syntax is
  3553 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3554 
  3555 * some more standard symbols; see Appendix A of the system manual for
  3556 the complete list of symbols defined in isabellesym.sty;
  3557 
  3558 * improved isabelle style files; more abstract symbol implementation
  3559 (should now use \isamath{...} and \isatext{...} in custom symbol
  3560 definitions);
  3561 
  3562 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3563 state; Note that presentation of goal states does not conform to
  3564 actual human-readable proof documents.  Please do not include goal
  3565 states into document output unless you really know what you are doing!
  3566 
  3567 * proper indentation of antiquoted output with proportional LaTeX
  3568 fonts;
  3569 
  3570 * no_document ML operator temporarily disables LaTeX document
  3571 generation;
  3572 
  3573 * isatool unsymbolize tunes sources for plain ASCII communication;
  3574 
  3575 
  3576 *** Isar ***
  3577 
  3578 * Pure: Isar now suffers initial goal statements to contain unbound
  3579 schematic variables (this does not conform to actual readable proof
  3580 documents, due to unpredictable outcome and non-compositional proof
  3581 checking); users who know what they are doing may use schematic goals
  3582 for Prolog-style synthesis of proven results;
  3583 
  3584 * Pure: assumption method (an implicit finishing) now handles actual
  3585 rules as well;
  3586 
  3587 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3588 initial goal, declare "that" only as Pure intro (only for single
  3589 steps); the "that" rule assumption may now be involved in implicit
  3590 finishing, thus ".." becomes a feasible for trivial obtains;
  3591 
  3592 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3593 instance proofs may be performed by "..";
  3594 
  3595 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3596 statements as well;
  3597 
  3598 * Pure: more robust selection of calculational rules;
  3599 
  3600 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3601 rule (as well as the assumption rule);
  3602 
  3603 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3604 lemmas, using the graph browser tool;
  3605 
  3606 * Pure: predict failure of "show" in interactive mode;
  3607 
  3608 * Pure: 'thms_containing' now takes actual terms as arguments;
  3609 
  3610 * HOL: improved method 'induct' --- now handles non-atomic goals
  3611 (potential INCOMPATIBILITY); tuned error handling;
  3612 
  3613 * HOL: cases and induct rules now provide explicit hints about the
  3614 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3615 any remaining facts are inserted into the goal verbatim;
  3616 
  3617 * HOL: local contexts (aka cases) may now contain term bindings as
  3618 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3619 the result to be shown in each case;
  3620 
  3621 * HOL: added 'recdef_tc' command;
  3622 
  3623 * isatool convert assists in eliminating legacy ML scripts;
  3624 
  3625 
  3626 *** HOL ***
  3627 
  3628 * HOL/Library: a collection of generic theories to be used together
  3629 with main HOL; the theory loader path already includes this directory
  3630 by default; the following existing theories have been moved here:
  3631 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3632 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3633 
  3634 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3635 modelling and verification task performed in Isabelle/HOL +
  3636 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3637 
  3638 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3639 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3640 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3641 'domain', this makes the theory consistent with mathematical
  3642 literature;
  3643 
  3644 * HOL basics: added overloaded operations "inverse" and "divide"
  3645 (infix "/"), syntax for generic "abs" operation, generic summation
  3646 operator \<Sum>;
  3647 
  3648 * HOL/typedef: simplified package, provide more useful rules (see also
  3649 HOL/subset.thy);
  3650 
  3651 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3652 now expressed as a proper nested rule (old-style tactic scripts may
  3653 require atomize_strip_tac to cope with non-atomic premises);
  3654 
  3655 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3656 to "split_conv" (old name still available for compatibility);
  3657 
  3658 * HOL: improved concrete syntax for strings (e.g. allows translation
  3659 rules with string literals);
  3660 
  3661 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3662  and Fleuriot's mechanization of analysis, including the transcendental
  3663  functions for the reals;
  3664 
  3665 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3666 
  3667 
  3668 *** CTT ***
  3669 
  3670 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3671 "lam" is displayed as TWO lambda-symbols
  3672 
  3673 * CTT: theory Main now available, containing everything (that is, Bool
  3674 and Arith);
  3675 
  3676 
  3677 *** General ***
  3678 
  3679 * Pure: the Simplifier has been implemented properly as a derived rule
  3680 outside of the actual kernel (at last!); the overall performance
  3681 penalty in practical applications is about 50%, while reliability of
  3682 the Isabelle inference kernel has been greatly improved;
  3683 
  3684 * print modes "brackets" and "no_brackets" control output of nested =>
  3685 (types) and ==> (props); the default behaviour is "brackets";
  3686 
  3687 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3688 as assumptions as well;
  3689 
  3690 * system: support Poly/ML 4.0;
  3691 
  3692 * system: isatool install handles KDE version 1 or 2;
  3693 
  3694 
  3695 
  3696 New in Isabelle99-1 (October 2000)
  3697 ----------------------------------
  3698 
  3699 *** Overview of INCOMPATIBILITIES ***
  3700 
  3701 * HOL: simplification of natural numbers is much changed; to partly
  3702 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3703 issue the following ML commands:
  3704 
  3705   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3706   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3707 
  3708 * HOL: simplification no longer dives into case-expressions; this is
  3709 controlled by "t.weak_case_cong" for each datatype t;
  3710 
  3711 * HOL: nat_less_induct renamed to less_induct;
  3712 
  3713 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3714 fixsome to patch .thy and .ML sources automatically;
  3715 
  3716   select_equality  -> some_equality
  3717   select_eq_Ex     -> some_eq_ex
  3718   selectI2EX       -> someI2_ex
  3719   selectI2         -> someI2
  3720   selectI          -> someI
  3721   select1_equality -> some1_equality
  3722   Eps_sym_eq       -> some_sym_eq_trivial
  3723   Eps_eq           -> some_eq_trivial
  3724 
  3725 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3726 
  3727 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3728 instead);
  3729 
  3730 * HOL: the recursion equations generated by 'recdef' are now called
  3731 f.simps instead of f.rules;
  3732 
  3733 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3734 
  3735 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3736 sometimes be needed;
  3737 
  3738 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3739 
  3740 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3741 
  3742 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3743 product is now "<*>" instead of "Times"; the lexicographic product is
  3744 now "<*lex*>" instead of "**";
  3745 
  3746 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3747 of main HOL, but was unused); better use HOL's datatype package;
  3748 
  3749 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3750 the old syntax may be recovered as follows:
  3751 
  3752   syntax (symbols)
  3753     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3754       (infixl "\\<oplus>" 100)
  3755 
  3756 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3757 
  3758 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3759 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3760 internally;
  3761 
  3762 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3763 changed from A/r to A//r;
  3764 
  3765 * ZF: new treatment of arithmetic (nat & int) may break some old
  3766 proofs;
  3767 
  3768 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3769 rulify -> rule_format, elimify -> elim_format, ...);
  3770 
  3771 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3772 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3773 should have to change intro!! to intro? only); replaced "delrule" by
  3774 "rule del";
  3775 
  3776 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3777 
  3778 * Provers: strengthened force_tac by using new first_best_tac;
  3779 
  3780 * LaTeX document preparation: several changes of isabelle.sty (see
  3781 lib/texinputs);
  3782 
  3783 
  3784 *** Document preparation ***
  3785 
  3786 * formal comments (text blocks etc.) in new-style theories may now
  3787 contain antiquotations of thm/prop/term/typ/text to be presented
  3788 according to latex print mode; concrete syntax is like this:
  3789 @{term[show_types] "f(x) = a + x"};
  3790 
  3791 * isatool mkdir provides easy setup of Isabelle session directories,
  3792 including proper document sources;
  3793 
  3794 * generated LaTeX sources are now deleted after successful run
  3795 (isatool document -c); may retain a copy somewhere else via -D option
  3796 of isatool usedir;
  3797 
  3798 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3799 style files, achieving self-contained LaTeX sources and simplifying
  3800 LaTeX debugging;
  3801 
  3802 * old-style theories now produce (crude) LaTeX output as well;
  3803 
  3804 * browser info session directories are now self-contained (may be put
  3805 on WWW server seperately); improved graphs of nested sessions; removed
  3806 graph for 'all sessions';
  3807 
  3808 * several improvements in isabelle style files; \isabellestyle{it}
  3809 produces fake math mode output; \isamarkupheader is now \section by
  3810 default; see lib/texinputs/isabelle.sty etc.;
  3811 
  3812 
  3813 *** Isar ***
  3814 
  3815 * Isar/Pure: local results and corresponding term bindings are now
  3816 subject to Hindley-Milner polymorphism (similar to ML); this
  3817 accommodates incremental type-inference very nicely;
  3818 
  3819 * Isar/Pure: new derived language element 'obtain' supports
  3820 generalized existence reasoning;
  3821 
  3822 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3823 support accumulation of results, without applying any rules yet;
  3824 useful to collect intermediate results without explicit name
  3825 references, and for use with transitivity rules with more than 2
  3826 premises;
  3827 
  3828 * Isar/Pure: scalable support for case-analysis type proofs: new
  3829 'case' language element refers to local contexts symbolically, as
  3830 produced by certain proof methods; internally, case names are attached
  3831 to theorems as "tags";
  3832 
  3833 * Isar/Pure: theory command 'hide' removes declarations from
  3834 class/type/const name spaces;
  3835 
  3836 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3837 indicate potential overloading;
  3838 
  3839 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3840 
  3841 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3842 "{a,b,c}" instead of {a,b,c};
  3843 
  3844 * Isar/Pure now provides its own version of intro/elim/dest
  3845 attributes; useful for building new logics, but beware of confusion
  3846 with the version in Provers/classical;
  3847 
  3848 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3849 case name 'antecedent';
  3850 
  3851 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3852 to the current context is now done automatically);
  3853 
  3854 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3855 for definining proof methods in ML;
  3856 
  3857 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3858 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3859 most cases, one should have to change intro!! to intro? only);
  3860 replaced "delrule" by "rule del";
  3861 
  3862 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3863 'symmetric' attribute (the latter supercedes [RS sym]);
  3864 
  3865 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3866 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3867 well (including splits);
  3868 
  3869 * Isar/Provers: Simplifier and Classical methods now support all kind
  3870 of modifiers used in the past, including 'cong', 'iff', etc.
  3871 
  3872 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3873 of Simplifier and Classical reasoner);
  3874 
  3875 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3876 now support named cases; major packages (inductive, datatype, primrec,
  3877 recdef) support case names and properly name parameters;
  3878 
  3879 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3880 monotonicity conditions are extracted to be proven at end of
  3881 calculations;
  3882 
  3883 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3884 method anyway;
  3885 
  3886 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3887 split_if split_if_asm; datatype package provides theorems foo.splits =
  3888 foo.split foo.split_asm for each datatype;
  3889 
  3890 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3891 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3892 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3893 use "(cases (simplified))" method in proper proof texts);
  3894 
  3895 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3896 
  3897 * Isar: names of theorems etc. may be natural numbers as well;
  3898 
  3899 * Isar: 'pr' command: optional arguments for goals_limit and
  3900 ProofContext.prems_limit; no longer prints theory contexts, but only
  3901 proof states;
  3902 
  3903 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3904 additional print modes to be specified; e.g. "pr(latex)" will print
  3905 proof state according to the Isabelle LaTeX style;
  3906 
  3907 * Isar: improved support for emulating tactic scripts, including proof
  3908 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3909 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3910 (for HOL datatypes);
  3911 
  3912 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3913 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3914 'proof method scripts' have to be in depth-first order;
  3915 
  3916 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3917 
  3918 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3919 should instead use individual commands for printing items
  3920 (print_commands, print_methods etc.);
  3921 
  3922 * Isar: added 'nothing' --- the empty list of theorems;
  3923 
  3924 
  3925 *** HOL ***
  3926 
  3927 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3928 corresponding virtual machine and a specification of its bytecode
  3929 verifier and a lightweight bytecode verifier, including proofs of
  3930 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3931 Cornelia Pusch (see also the homepage of project Bali at
  3932 http://isabelle.in.tum.de/Bali/);
  3933 
  3934 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3935 Clemens Ballarin;
  3936 
  3937 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3938 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3939 Rasmussen;
  3940 
  3941 * HOL/Lattice: fundamental concepts of lattice theory and order
  3942 structures, including duals, properties of bounds versus algebraic
  3943 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3944 Theorem for complete lattices etc.; may also serve as a demonstration
  3945 for abstract algebraic reasoning using axiomatic type classes, and
  3946 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3947 
  3948 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3949 von Oheimb;
  3950 
  3951 * HOL/IMPP: extension of IMP with local variables and mutually
  3952 recursive procedures, by David von Oheimb;
  3953 
  3954 * HOL/Lambda: converted into new-style theory and document;
  3955 
  3956 * HOL/ex/Multiquote: example of multiple nested quotations and
  3957 anti-quotations -- basically a generalized version of de-Bruijn
  3958 representation; very useful in avoiding lifting of operations;
  3959 
  3960 * HOL/record: added general record equality rule to simpset; fixed
  3961 select-update simplification procedure to handle extended records as
  3962 well; admit "r" as field name;
  3963 
  3964 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3965 other numeric types and also as the identity of groups, rings, etc.;
  3966 
  3967 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3968 Types nat and int belong to this axclass;
  3969 
  3970 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3971    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3972    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3973   two terms #m*u and #n*u are replaced by #(m+n)*u
  3974     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3975   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3976     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3977 
  3978 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3979 powerful prover for predicate logic but knows nothing of clasets; see
  3980 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3981 
  3982 * HOL: new version of "case_tac" subsumes both boolean case split and
  3983 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3984 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3985 
  3986 * HOL: simplification no longer dives into case-expressions: only the
  3987 selector expression is simplified, but not the remaining arms; to
  3988 enable full simplification of case-expressions for datatype t, you may
  3989 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3990 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3991 
  3992 * HOL/recdef: the recursion equations generated by 'recdef' for
  3993 function 'f' are now called f.simps instead of f.rules; if all
  3994 termination conditions are proved automatically, these simplification
  3995 rules are added to the simpset, as in primrec; rules may be named
  3996 individually as well, resulting in a separate list of theorems for
  3997 each equation;
  3998 
  3999 * HOL/While is a new theory that provides a while-combinator. It
  4000 permits the definition of tail-recursive functions without the
  4001 provision of a termination measure. The latter is necessary once the
  4002 invariant proof rule for while is applied.
  4003 
  4004 * HOL: new (overloaded) notation for the set of elements below/above
  4005 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4006 
  4007 * HOL: theorems impI, allI, ballI bound as "strip";
  4008 
  4009 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4010 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4011 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4012 
  4013 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4014 
  4015 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4016 main HOL, but was unused);
  4017 
  4018 * HOL: fewer consts declared as global (e.g. have to refer to
  4019 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4020 
  4021 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4022 in case of overlap with user translations (e.g. judgements over
  4023 tuples); (note that the underlying logical represenation is still
  4024 bogus);
  4025 
  4026 
  4027 *** ZF ***
  4028 
  4029 * ZF: simplification automatically cancels common terms in arithmetic
  4030 expressions over nat and int;
  4031 
  4032 * ZF: new treatment of nat to minimize type-checking: all operators
  4033 coerce their operands to a natural number using the function natify,
  4034 making the algebraic laws unconditional;
  4035 
  4036 * ZF: as above, for int: operators coerce their operands to an integer
  4037 using the function intify;
  4038 
  4039 * ZF: the integer library now contains many of the usual laws for the
  4040 orderings, including $<=, and monotonicity laws for $+ and $*;
  4041 
  4042 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4043 simplification;
  4044 
  4045 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4046 to the simplifier and classical reasoner simultaneously;
  4047 
  4048 
  4049 *** General ***
  4050 
  4051 * Provers: blast_tac now handles actual object-logic rules as
  4052 assumptions; note that auto_tac uses blast_tac internally as well;
  4053 
  4054 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4055 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4056 
  4057 * Provers: delrules now handles destruct rules as well (no longer need
  4058 explicit make_elim);
  4059 
  4060 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4061   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4062 use instead the strong form,
  4063   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4064 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4065 from destruct-rules;
  4066 
  4067 * Provers: Simplifier.easy_setup provides a fast path to basic
  4068 Simplifier setup for new object-logics;
  4069 
  4070 * Pure: AST translation rules no longer require constant head on LHS;
  4071 
  4072 * Pure: improved name spaces: ambiguous output is qualified; support
  4073 for hiding of names;
  4074 
  4075 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4076 XSYMBOL_HOME; no longer need to do manual configuration in most
  4077 situations;
  4078 
  4079 * system: compression of ML heaps images may now be controlled via -c
  4080 option of isabelle and isatool usedir (currently only observed by
  4081 Poly/ML);
  4082 
  4083 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4084 useful for remote X11);
  4085 
  4086 * system: provide TAGS file for Isabelle sources;
  4087 
  4088 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4089 order;
  4090 
  4091 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4092 timing flag supersedes proof_timing and Toplevel.trace;
  4093 
  4094 * ML: new combinators |>> and |>>> for incremental transformations
  4095 with secondary results (e.g. certain theory extensions):
  4096 
  4097 * ML: PureThy.add_defs gets additional argument to indicate potential
  4098 overloading (usually false);
  4099 
  4100 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4101 results;
  4102 
  4103 
  4104 
  4105 New in Isabelle99 (October 1999)
  4106 --------------------------------
  4107 
  4108 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4109 
  4110 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4111 are no longer simplified.  (This allows the simplifier to unfold recursive
  4112 functional programs.)  To restore the old behaviour, declare
  4113 
  4114     Delcongs [if_weak_cong];
  4115 
  4116 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4117 complement;
  4118 
  4119 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4120 
  4121 * HOL/datatype: mutual_induct_tac no longer exists --
  4122   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4123 
  4124 * HOL/typedef: fixed type inference for representing set; type
  4125 arguments now have to occur explicitly on the rhs as type constraints;
  4126 
  4127 * ZF: The con_defs part of an inductive definition may no longer refer
  4128 to constants declared in the same theory;
  4129 
  4130 * HOL, ZF: the function mk_cases, generated by the inductive
  4131 definition package, has lost an argument.  To simplify its result, it
  4132 uses the default simpset instead of a supplied list of theorems.
  4133 
  4134 * HOL/List: the constructors of type list are now Nil and Cons;
  4135 
  4136 * Simplifier: the type of the infix ML functions
  4137         setSSolver addSSolver setSolver addSolver
  4138 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4139 for packaging solvers. A solver is created via
  4140         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4141 where the string argument is only a comment.
  4142 
  4143 
  4144 *** Proof tools ***
  4145 
  4146 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4147 decision procedure for linear arithmetic. Currently it is used for
  4148 types `nat', `int', and `real' in HOL (see below); it can, should and
  4149 will be instantiated for other types and logics as well.
  4150 
  4151 * The simplifier now accepts rewrite rules with flexible heads, eg
  4152      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4153   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4154   matching.
  4155 
  4156 
  4157 *** General ***
  4158 
  4159 * New Isabelle/Isar subsystem provides an alternative to traditional
  4160 tactical theorem proving; together with the ProofGeneral/isar user
  4161 interface it offers an interactive environment for developing human
  4162 readable proof documents (Isar == Intelligible semi-automated
  4163 reasoning); for further information see isatool doc isar-ref,
  4164 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4165 
  4166 * improved and simplified presentation of theories: better HTML markup
  4167 (including colors), graph views in several sizes; isatool usedir now
  4168 provides a proper interface for user theories (via -P option); actual
  4169 document preparation based on (PDF)LaTeX is available as well (for
  4170 new-style theories only); see isatool doc system for more information;
  4171 
  4172 * native support for Proof General, both for classic Isabelle and
  4173 Isabelle/Isar;
  4174 
  4175 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4176 using the graph browser tool;
  4177 
  4178 * Isabelle manuals now also available as PDF;
  4179 
  4180 * theory loader rewritten from scratch (may not be fully
  4181 bug-compatible); old loadpath variable has been replaced by show_path,
  4182 add_path, del_path, reset_path functions; new operations such as
  4183 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4184 isatool doc ref);
  4185 
  4186 * improved isatool install: option -k creates KDE application icon,
  4187 option -p DIR installs standalone binaries;
  4188 
  4189 * added ML_PLATFORM setting (useful for cross-platform installations);
  4190 more robust handling of platform specific ML images for SML/NJ;
  4191 
  4192 * the settings environment is now statically scoped, i.e. it is never
  4193 created again in sub-processes invoked from isabelle, isatool, or
  4194 Isabelle;
  4195 
  4196 * path element specification '~~' refers to '$ISABELLE_HOME';
  4197 
  4198 * in locales, the "assumes" and "defines" parts may be omitted if
  4199 empty;
  4200 
  4201 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4202 long arrows);
  4203 
  4204 * new print_mode "HTML";
  4205 
  4206 * new flag show_tags controls display of tags of theorems (which are
  4207 basically just comments that may be attached by some tools);
  4208 
  4209 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4210 mode and goal output format:
  4211 
  4212 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4213 244c244
  4214 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4215 ---
  4216 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4217 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4218 181c181
  4219 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4220 ---
  4221 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4222 
  4223 * function bind_thms stores lists of theorems (cf. bind_thm);
  4224 
  4225 * new shorthand tactics ftac, eatac, datac, fatac;
  4226 
  4227 * qed (and friends) now accept "" as result name; in that case the
  4228 theorem is not stored, but proper checks and presentation of the
  4229 result still apply;
  4230 
  4231 * theorem database now also indexes constants "Trueprop", "all",
  4232 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4233 
  4234 
  4235 *** HOL ***
  4236 
  4237 ** HOL arithmetic **
  4238 
  4239 * There are now decision procedures for linear arithmetic over nat and
  4240 int:
  4241 
  4242 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4243 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4244 are treated as atomic; subformulae not involving type `nat' or `int'
  4245 are ignored; quantified subformulae are ignored unless they are
  4246 positive universal or negative existential. The tactic has to be
  4247 invoked by hand and can be a little bit slow. In particular, the
  4248 running time is exponential in the number of occurrences of `min' and
  4249 `max', and `-' on `nat'.
  4250 
  4251 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4252 (negated) (in)equalities among the premises and the conclusion into
  4253 account (i.e. no compound formulae) and does not know about `min' and
  4254 `max', and `-' on `nat'. It is fast and is used automatically by the
  4255 simplifier.
  4256 
  4257 NB: At the moment, these decision procedures do not cope with mixed
  4258 nat/int formulae where the two parts interact, such as `m < n ==>
  4259 int(m) < int(n)'.
  4260 
  4261 * HOL/Numeral provides a generic theory of numerals (encoded
  4262 efficiently as bit strings); setup for types nat/int/real is in place;
  4263 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4264 int, existing theories and proof scripts may require a few additional
  4265 type constraints;
  4266 
  4267 * integer division and remainder can now be performed on constant
  4268 arguments;
  4269 
  4270 * many properties of integer multiplication, division and remainder
  4271 are now available;
  4272 
  4273 * An interface to the Stanford Validity Checker (SVC) is available through the
  4274 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4275 are proved automatically.  SVC must be installed separately, and its results
  4276 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4277 invocation of the underlying oracle).  For SVC see
  4278   http://verify.stanford.edu/SVC
  4279 
  4280 * IsaMakefile: the HOL-Real target now builds an actual image;
  4281 
  4282 
  4283 ** HOL misc **
  4284 
  4285 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4286 (in Isabelle/Isar) -- by Gertrud Bauer;
  4287 
  4288 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4289 analysis for assembly languages with subtypes;
  4290 
  4291 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4292 -- avoids syntactic ambiguities and treats state, transition, and
  4293 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4294 changed syntax and (many) tactics;
  4295 
  4296 * HOL/inductive: Now also handles more general introduction rules such
  4297   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4298   theorems are now maintained within the theory (maintained via the
  4299   "mono" attribute);
  4300 
  4301 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4302   (using function types) such as
  4303 
  4304   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4305 
  4306 * HOL/record: record_simproc (part of the default simpset) takes care
  4307 of selectors applied to updated records; record_split_tac is no longer
  4308 part of the default claset; update_defs may now be removed from the
  4309 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4310 
  4311   claset_ref () := claset() addSWrapper record_split_wrapper;
  4312   Delsimprocs [record_simproc]
  4313 
  4314 * HOL/typedef: fixed type inference for representing set; type
  4315 arguments now have to occur explicitly on the rhs as type constraints;
  4316 
  4317 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4318 names rather than an ML expression;
  4319 
  4320 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4321 supplied later.  Program schemes can be defined, such as
  4322     "While B C s = (if B s then While B C (C s) else s)"
  4323 where the well-founded relation can be chosen after B and C have been given.
  4324 
  4325 * HOL/List: the constructors of type list are now Nil and Cons;
  4326 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4327 course, ML tools referring to List.list.op # etc. have to be adapted;
  4328 
  4329 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4330 disabled by default; run isabelle with option -m HOL to get back to
  4331 the original Gordon/HOL-style output;
  4332 
  4333 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4334 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4335 
  4336 * HOL basic syntax simplified (more orthogonal): all variants of
  4337 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4338 Eps operator is provided as well: "SOME x. P[x]";
  4339 
  4340 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4341 
  4342 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4343 thus available for user theories;
  4344 
  4345 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4346 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4347 time;
  4348 
  4349 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4350 several times and then mp;
  4351 
  4352 
  4353 *** LK ***
  4354 
  4355 * the notation <<...>> is now available as a notation for sequences of
  4356 formulas;
  4357 
  4358 * the simplifier is now installed
  4359 
  4360 * the axiom system has been generalized (thanks to Soren Heilmann)
  4361 
  4362 * the classical reasoner now has a default rule database
  4363 
  4364 
  4365 *** ZF ***
  4366 
  4367 * new primrec section allows primitive recursive functions to be given
  4368 directly (as in HOL) over datatypes and the natural numbers;
  4369 
  4370 * new tactics induct_tac and exhaust_tac for induction (or case
  4371 analysis) over datatypes and the natural numbers;
  4372 
  4373 * the datatype declaration of type T now defines the recursor T_rec;
  4374 
  4375 * simplification automatically does freeness reasoning for datatype
  4376 constructors;
  4377 
  4378 * automatic type-inference, with AddTCs command to insert new
  4379 type-checking rules;
  4380 
  4381 * datatype introduction rules are now added as Safe Introduction rules
  4382 to the claset;
  4383 
  4384 * the syntax "if P then x else y" is now available in addition to
  4385 if(P,x,y);
  4386 
  4387 
  4388 *** Internal programming interfaces ***
  4389 
  4390 * tuned simplifier trace output; new flag debug_simp;
  4391 
  4392 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4393 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4394 
  4395 * AxClass.axclass_tac lost the theory argument;
  4396 
  4397 * tuned current_goals_markers semantics: begin / end goal avoids
  4398 printing empty lines;
  4399 
  4400 * removed prs and prs_fn hook, which was broken because it did not
  4401 include \n in its semantics, forcing writeln to add one
  4402 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4403 string -> unit if you really want to output text without newline;
  4404 
  4405 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4406 plain output, interface builders may have to enable 'isabelle_font'
  4407 mode to get Isabelle font glyphs as before;
  4408 
  4409 * refined token_translation interface; INCOMPATIBILITY: output length
  4410 now of type real instead of int;
  4411 
  4412 * theory loader actions may be traced via new ThyInfo.add_hook
  4413 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4414 your own database of information attached to *whole* theories -- as
  4415 opposed to intra-theory data slots offered via TheoryDataFun;
  4416 
  4417 * proper handling of dangling sort hypotheses (at last!);
  4418 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4419 extra sort hypotheses that can be witnessed from the type signature;
  4420 the force_strip_shyps flag is gone, any remaining shyps are simply
  4421 left in the theorem (with a warning issued by strip_shyps_warning);
  4422 
  4423 
  4424 
  4425 New in Isabelle98-1 (October 1998)
  4426 ----------------------------------
  4427 
  4428 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4429 
  4430 * several changes of automated proof tools;
  4431 
  4432 * HOL: major changes to the inductive and datatype packages, including
  4433 some minor incompatibilities of theory syntax;
  4434 
  4435 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4436 called `inj_on';
  4437 
  4438 * HOL: removed duplicate thms in Arith:
  4439   less_imp_add_less  should be replaced by  trans_less_add1
  4440   le_imp_add_le      should be replaced by  trans_le_add1
  4441 
  4442 * HOL: unary minus is now overloaded (new type constraints may be
  4443 required);
  4444 
  4445 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4446 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4447 now taken as an integer constant.
  4448 
  4449 * Pure: ML function 'theory_of' renamed to 'theory';
  4450 
  4451 
  4452 *** Proof tools ***
  4453 
  4454 * Simplifier:
  4455   1. Asm_full_simp_tac is now more aggressive.
  4456      1. It will sometimes reorient premises if that increases their power to
  4457         simplify.
  4458      2. It does no longer proceed strictly from left to right but may also
  4459         rotate premises to achieve further simplification.
  4460      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4461      old Asm_full_simp_tac in that it does not rotate premises.
  4462   2. The simplifier now knows a little bit about nat-arithmetic.
  4463 
  4464 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4465 allows for selected deletion of wrappers, by introduction of names for
  4466 wrapper functionals.  This implies that addbefore, addSbefore,
  4467 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4468 and that adding two tactics with the same name overwrites the first
  4469 one (emitting a warning).
  4470   type wrapper = (int -> tactic) -> (int -> tactic)
  4471   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4472   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4473   delWrapper, delSWrapper: claset *  string            -> claset
  4474   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4475 
  4476 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4477 semantics; addbefore now affects only the unsafe part of step_tac
  4478 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4479 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4480 by Force_tac;
  4481 
  4482 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4483 compWrapper; added safe wrapper (and access functions for it);
  4484 
  4485 * HOL/split_all_tac is now much faster and fails if there is nothing
  4486 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4487 and the names of the automatically generated variables have changed.
  4488 split_all_tac has moved within claset() from unsafe wrappers to safe
  4489 wrappers, which means that !!-bound variables are split much more
  4490 aggressively, and safe_tac and clarify_tac now split such variables.
  4491 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4492 Note: the same holds for record_split_tac, which does the job of
  4493 split_all_tac for record fields.
  4494 
  4495 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4496 permanently to the default simpset using Addsplits just like
  4497 Addsimps. They can be removed via Delsplits just like
  4498 Delsimps. Lower-case versions are also available.
  4499 
  4500 * HOL/Simplifier: The rule split_if is now part of the default
  4501 simpset. This means that the simplifier will eliminate all occurrences
  4502 of if-then-else in the conclusion of a goal. To prevent this, you can
  4503 either remove split_if completely from the default simpset by
  4504 `Delsplits [split_if]' or remove it in a specific call of the
  4505 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4506 other case splitting rules to/from the default simpset: every datatype
  4507 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4508 t is the name of the datatype).
  4509 
  4510 * Classical reasoner / Simplifier combination: new force_tac (and
  4511 derivatives Force_tac, force) combines rewriting and classical
  4512 reasoning (and whatever other tools) similarly to auto_tac, but is
  4513 aimed to solve the given subgoal completely.
  4514 
  4515 
  4516 *** General ***
  4517 
  4518 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4519 and `goalw': the theory is no longer needed as an explicit argument -
  4520 the current theory context is used; assumptions are no longer returned
  4521 at the ML-level unless one of them starts with ==> or !!; it is
  4522 recommended to convert to these new commands using isatool fixgoal
  4523 (backup your sources first!);
  4524 
  4525 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4526 the current theory context, and 'theory' to lookup stored theories;
  4527 
  4528 * new theory section 'locale' for declaring constants, assumptions and
  4529 definitions that have local scope;
  4530 
  4531 * new theory section 'nonterminals' for purely syntactic types;
  4532 
  4533 * new theory section 'setup' for generic ML setup functions
  4534 (e.g. package initialization);
  4535 
  4536 * the distribution now includes Isabelle icons: see
  4537 lib/logo/isabelle-{small,tiny}.xpm;
  4538 
  4539 * isatool install - install binaries with absolute references to
  4540 ISABELLE_HOME/bin;
  4541 
  4542 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4543 
  4544 * print mode 'emacs' reserved for Isamode;
  4545 
  4546 * support multiple print (ast) translations per constant name;
  4547 
  4548 * theorems involving oracles are now printed with a suffixed [!];
  4549 
  4550 
  4551 *** HOL ***
  4552 
  4553 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4554 
  4555 * HOL/inductive package reorganized and improved: now supports mutual
  4556 definitions such as
  4557 
  4558   inductive EVEN ODD
  4559     intrs
  4560       null "0 : EVEN"
  4561       oddI "n : EVEN ==> Suc n : ODD"
  4562       evenI "n : ODD ==> Suc n : EVEN"
  4563 
  4564 new theorem list "elims" contains an elimination rule for each of the
  4565 recursive sets; inductive definitions now handle disjunctive premises
  4566 correctly (also ZF);
  4567 
  4568 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4569 "mutual_induct" no longer exists - the induction rule is always
  4570 contained in "induct";
  4571 
  4572 
  4573 * HOL/datatype package re-implemented and greatly improved: now
  4574 supports mutually recursive datatypes such as
  4575 
  4576   datatype
  4577     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4578             | SUM ('a aexp) ('a aexp)
  4579             | DIFF ('a aexp) ('a aexp)
  4580             | NUM 'a
  4581   and
  4582     'a bexp = LESS ('a aexp) ('a aexp)
  4583             | AND ('a bexp) ('a bexp)
  4584             | OR ('a bexp) ('a bexp)
  4585 
  4586 as well as indirectly recursive datatypes such as
  4587 
  4588   datatype
  4589     ('a, 'b) term = Var 'a
  4590                   | App 'b ((('a, 'b) term) list)
  4591 
  4592 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4593 induction on mutually / indirectly recursive datatypes.
  4594 
  4595 Primrec equations are now stored in theory and can be accessed via
  4596 <function_name>.simps.
  4597 
  4598 INCOMPATIBILITIES:
  4599 
  4600   - Theories using datatypes must now have theory Datatype as an
  4601     ancestor.
  4602   - The specific <typename>.induct_tac no longer exists - use the
  4603     generic induct_tac instead.
  4604   - natE has been renamed to nat.exhaust - use exhaust_tac
  4605     instead of res_inst_tac ... natE. Note that the variable
  4606     names in nat.exhaust differ from the names in natE, this
  4607     may cause some "fragile" proofs to fail.
  4608   - The theorems split_<typename>_case and split_<typename>_case_asm
  4609     have been renamed to <typename>.split and <typename>.split_asm.
  4610   - Since default sorts of type variables are now handled correctly,
  4611     some datatype definitions may have to be annotated with explicit
  4612     sort constraints.
  4613   - Primrec definitions no longer require function name and type
  4614     of recursive argument.
  4615 
  4616 Consider using isatool fixdatatype to adapt your theories and proof
  4617 scripts to the new package (backup your sources first!).
  4618 
  4619 
  4620 * HOL/record package: considerably improved implementation; now
  4621 includes concrete syntax for record types, terms, updates; theorems
  4622 for surjective pairing and splitting !!-bound record variables; proof
  4623 support is as follows:
  4624 
  4625   1) standard conversions (selectors or updates applied to record
  4626 constructor terms) are part of the standard simpset;
  4627 
  4628   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4629 made part of standard simpset and claset via addIffs;
  4630 
  4631   3) a tactic for record field splitting (record_split_tac) is part of
  4632 the standard claset (addSWrapper);
  4633 
  4634 To get a better idea about these rules you may retrieve them via
  4635 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4636 the name of your record type.
  4637 
  4638 The split tactic 3) conceptually simplifies by the following rule:
  4639 
  4640   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4641 
  4642 Thus any record variable that is bound by meta-all will automatically
  4643 blow up into some record constructor term, consequently the
  4644 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4645 solve record problems automatically.
  4646 
  4647 
  4648 * reorganized the main HOL image: HOL/Integ and String loaded by
  4649 default; theory Main includes everything;
  4650 
  4651 * automatic simplification of integer sums and comparisons, using cancellation;
  4652 
  4653 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4654 
  4655 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4656 
  4657 * many new identities for unions, intersections, set difference, etc.;
  4658 
  4659 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4660 called split_if, split_split, split_sum_case and split_nat_case (to go
  4661 with add/delsplits);
  4662 
  4663 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4664 (?x::unit) = (); this is made part of the default simpset, which COULD
  4665 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4666 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4667 unit_abs_eta_conv is added in order to counter the effect of
  4668 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4669 %u.f();
  4670 
  4671 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4672 makes more sense);
  4673 
  4674 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4675   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4676   disjointness reasoning but breaking a few old proofs.
  4677 
  4678 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4679 to 'converse' from 'inverse' (for compatibility with ZF and some
  4680 literature);
  4681 
  4682 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4683 the well-founded relation;
  4684 
  4685 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4686     Compl A.  The "Compl" syntax remains available as input syntax for this
  4687     release ONLY.
  4688 
  4689 * HOL/Update: new theory of function updates:
  4690     f(a:=b) == %x. if x=a then b else f x
  4691 may also be iterated as in f(a:=b,c:=d,...);
  4692 
  4693 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4694 
  4695 * HOL/List:
  4696   - new function list_update written xs[i:=v] that updates the i-th
  4697     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4698   - new function `upt' written [i..j(] which generates the list
  4699     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4700     bound write [i..j], which is a shorthand for [i..j+1(].
  4701   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4702 
  4703 * HOL/Arith:
  4704   - removed 'pred' (predecessor) function;
  4705   - generalized some theorems about n-1;
  4706   - many new laws about "div" and "mod";
  4707   - new laws about greatest common divisors (see theory ex/Primes);
  4708 
  4709 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4710 instead of "inverse";
  4711 
  4712 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4713   of the multiset ordering;
  4714 
  4715 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4716   (not included by default);
  4717 
  4718 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4719 
  4720 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4721   programs, i.e. different program variables may have different types.
  4722 
  4723 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4724   [previously, this check worked only if the rewrite rule was unconditional]
  4725   Now rew can involve either definitions or equalities (either == or =).
  4726 
  4727 
  4728 *** ZF ***
  4729 
  4730 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4731   only the theorems proved on ZF.ML;
  4732 
  4733 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4734   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4735   disjointness reasoning but breaking a few old proofs.
  4736 
  4737 * ZF/Update: new theory of function updates
  4738     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4739   may also be iterated as in f(a:=b,c:=d,...);
  4740 
  4741 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4742 
  4743 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4744   [previously, this check worked only if the rewrite rule was unconditional]
  4745   Now rew can involve either definitions or equalities (either == or =).
  4746 
  4747 * case_tac provided for compatibility with HOL
  4748     (like the old excluded_middle_tac, but with subgoals swapped)
  4749 
  4750 
  4751 *** Internal programming interfaces ***
  4752 
  4753 * Pure: several new basic modules made available for general use, see
  4754 also src/Pure/README;
  4755 
  4756 * improved the theory data mechanism to support encapsulation (data
  4757 kind name replaced by private Object.kind, acting as authorization
  4758 key); new type-safe user interface via functor TheoryDataFun; generic
  4759 print_data function becomes basically useless;
  4760 
  4761 * removed global_names compatibility flag -- all theory declarations
  4762 are qualified by default;
  4763 
  4764 * module Pure/Syntax now offers quote / antiquote translation
  4765 functions (useful for Hoare logic etc. with implicit dependencies);
  4766 see HOL/ex/Antiquote for an example use;
  4767 
  4768 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4769 cterm -> thm;
  4770 
  4771 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4772 subgoal;
  4773 
  4774 * Display.print_goals function moved to Locale.print_goals;
  4775 
  4776 * standard print function for goals supports current_goals_markers
  4777 variable for marking begin of proof, end of proof, start of goal; the
  4778 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4779 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4780 for example;
  4781 
  4782 
  4783 
  4784 New in Isabelle98 (January 1998)
  4785 --------------------------------
  4786 
  4787 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4788 
  4789 * changed lexical syntax of terms / types: dots made part of long
  4790 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4791 
  4792 * simpset (and claset) reference variable replaced by functions
  4793 simpset / simpset_ref;
  4794 
  4795 * no longer supports theory aliases (via merge) and non-trivial
  4796 implicit merge of thms' signatures;
  4797 
  4798 * most internal names of constants changed due to qualified names;
  4799 
  4800 * changed Pure/Sequence interface (see Pure/seq.ML);
  4801 
  4802 
  4803 *** General Changes ***
  4804 
  4805 * hierachically structured name spaces (for consts, types, axms, thms
  4806 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4807 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4808 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4809 long_names for fully qualified output names; NOTE: ML programs
  4810 (special tactics, packages etc.) referring to internal names may have
  4811 to be adapted to cope with fully qualified names; in case of severe
  4812 backward campatibility problems try setting 'global_names' at compile
  4813 time to have enrything declared within a flat name space; one may also
  4814 fine tune name declarations in theories via the 'global' and 'local'
  4815 section;
  4816 
  4817 * reimplemented the implicit simpset and claset using the new anytype
  4818 data filed in signatures; references simpset:simpset ref etc. are
  4819 replaced by functions simpset:unit->simpset and
  4820 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4821 to patch your ML files accordingly;
  4822 
  4823 * HTML output now includes theory graph data for display with Java
  4824 applet or isatool browser; data generated automatically via isatool
  4825 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4826 
  4827 * defs may now be conditional; improved rewrite_goals_tac to handle
  4828 conditional equations;
  4829 
  4830 * defs now admits additional type arguments, using TYPE('a) syntax;
  4831 
  4832 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4833 creates a new theory node; implicit merge of thms' signatures is
  4834 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4835 transfer:theory->thm->thm in (rare) cases;
  4836 
  4837 * improved handling of draft signatures / theories; draft thms (and
  4838 ctyps, cterms) are automatically promoted to real ones;
  4839 
  4840 * slightly changed interfaces for oracles: admit many per theory, named
  4841 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4842 
  4843 * print_goals: optional output of const types (set show_consts and
  4844 show_types);
  4845 
  4846 * improved output of warnings (###) and errors (***);
  4847 
  4848 * subgoal_tac displays a warning if the new subgoal has type variables;
  4849 
  4850 * removed old README and Makefiles;
  4851 
  4852 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4853 
  4854 * removed obsolete init_pps and init_database;
  4855 
  4856 * deleted the obsolete tactical STATE, which was declared by
  4857     fun STATE tacfun st = tacfun st st;
  4858 
  4859 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4860 (which abbreviates $HOME);
  4861 
  4862 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4863 use isatool fixseq to adapt your ML programs (this works for fully
  4864 qualified references to the Sequence structure only!);
  4865 
  4866 * use_thy no longer requires writable current directory; it always
  4867 reloads .ML *and* .thy file, if either one is out of date;
  4868 
  4869 
  4870 *** Classical Reasoner ***
  4871 
  4872 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4873 tactics that use classical reasoning to simplify a subgoal without
  4874 splitting it into several subgoals;
  4875 
  4876 * Safe_tac: like safe_tac but uses the default claset;
  4877 
  4878 
  4879 *** Simplifier ***
  4880 
  4881 * added simplification meta rules:
  4882     (asm_)(full_)simplify: simpset -> thm -> thm;
  4883 
  4884 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4885 logics (again);
  4886 
  4887 * added prems argument to simplification procedures;
  4888 
  4889 * HOL, FOL, ZF: added infix function `addsplits':
  4890   instead of `<simpset> setloop (split_tac <thms>)'
  4891   you can simply write `<simpset> addsplits <thms>'
  4892 
  4893 
  4894 *** Syntax ***
  4895 
  4896 * TYPE('a) syntax for type reflection terms;
  4897 
  4898 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4899 
  4900 * pretty printer: changed order of mixfix annotation preference (again!);
  4901 
  4902 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4903 
  4904 
  4905 *** HOL ***
  4906 
  4907 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4908   with `addloop' of the simplifier to faciliate case splitting in premises.
  4909 
  4910 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4911 
  4912 * HOL/Auth: new protocol proofs including some for the Internet
  4913   protocol TLS;
  4914 
  4915 * HOL/Map: new theory of `maps' a la VDM;
  4916 
  4917 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4918 cancelling out common nat summands from =, <, <= (in)equalities, or
  4919 differences; simplification procedures nat_cancel_factor for
  4920 cancelling common factor from =, <, <= (in)equalities over natural
  4921 sums; nat_cancel contains both kinds of procedures, it is installed by
  4922 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4923 
  4924 * HOL/simplifier: terms of the form
  4925   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4926   are rewritten to
  4927   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4928   and those of the form
  4929   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4930   are rewritten to
  4931   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4932 
  4933 * HOL/datatype
  4934   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4935 
  4936   P(t_case f1 ... fn x) =
  4937      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4938         ...
  4939        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4940      )
  4941 
  4942   and a theorem `split_t_case_asm' of the form
  4943 
  4944   P(t_case f1 ... fn x) =
  4945     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4946         ...
  4947        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4948      )
  4949   which can be added to a simpset via `addsplits'. The existing theorems
  4950   expand_list_case and expand_option_case have been renamed to
  4951   split_list_case and split_option_case.
  4952 
  4953 * HOL/Arithmetic:
  4954   - `pred n' is automatically converted to `n-1'.
  4955     Users are strongly encouraged not to use `pred' any longer,
  4956     because it will disappear altogether at some point.
  4957   - Users are strongly encouraged to write "0 < n" rather than
  4958     "n ~= 0". Theorems and proof tools have been modified towards this
  4959     `standard'.
  4960 
  4961 * HOL/Lists:
  4962   the function "set_of_list" has been renamed "set" (and its theorems too);
  4963   the function "nth" now takes its arguments in the reverse order and
  4964   has acquired the infix notation "!" as in "xs!n".
  4965 
  4966 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4967 
  4968 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4969   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4970 
  4971 * HOL/record: extensible records with schematic structural subtyping
  4972 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4973 still lacks various theorems and concrete record syntax;
  4974 
  4975 
  4976 *** HOLCF ***
  4977 
  4978 * removed "axioms" and "generated by" sections;
  4979 
  4980 * replaced "ops" section by extended "consts" section, which is capable of
  4981   handling the continuous function space "->" directly;
  4982 
  4983 * domain package:
  4984   . proves theorems immediately and stores them in the theory,
  4985   . creates hierachical name space,
  4986   . now uses normal mixfix annotations (instead of cinfix...),
  4987   . minor changes to some names and values (for consistency),
  4988   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4989   . separator between mutual domain defs: changed "," to "and",
  4990   . improved handling of sort constraints;  now they have to
  4991     appear on the left-hand side of the equations only;
  4992 
  4993 * fixed LAM <x,y,zs>.b syntax;
  4994 
  4995 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4996 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4997 
  4998 
  4999 *** FOL and ZF ***
  5000 
  5001 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5002   with `addloop' of the simplifier to faciliate case splitting in premises.
  5003 
  5004 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5005 in HOL, they strip ALL and --> from proved theorems;
  5006 
  5007 
  5008 
  5009 New in Isabelle94-8 (May 1997)
  5010 ------------------------------
  5011 
  5012 *** General Changes ***
  5013 
  5014 * new utilities to build / run / maintain Isabelle etc. (in parts
  5015 still somewhat experimental); old Makefiles etc. still functional;
  5016 
  5017 * new 'Isabelle System Manual';
  5018 
  5019 * INSTALL text, together with ./configure and ./build scripts;
  5020 
  5021 * reimplemented type inference for greater efficiency, better error
  5022 messages and clean internal interface;
  5023 
  5024 * prlim command for dealing with lots of subgoals (an easier way of
  5025 setting goals_limit);
  5026 
  5027 
  5028 *** Syntax ***
  5029 
  5030 * supports alternative (named) syntax tables (parser and pretty
  5031 printer); internal interface is provided by add_modesyntax(_i);
  5032 
  5033 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5034 be used in conjunction with the Isabelle symbol font; uses the
  5035 "symbols" syntax table;
  5036 
  5037 * added token_translation interface (may translate name tokens in
  5038 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5039 the current print_mode); IMPORTANT: user print translation functions
  5040 are responsible for marking newly introduced bounds
  5041 (Syntax.mark_boundT);
  5042 
  5043 * token translations for modes "xterm" and "xterm_color" that display
  5044 names in bold, underline etc. or colors (which requires a color
  5045 version of xterm);
  5046 
  5047 * infixes may now be declared with names independent of their syntax;
  5048 
  5049 * added typed_print_translation (like print_translation, but may
  5050 access type of constant);
  5051 
  5052 
  5053 *** Classical Reasoner ***
  5054 
  5055 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5056 some limitations.  Blast_tac...
  5057   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5058   + ignores elimination rules that don't have the correct format
  5059         (the conclusion MUST be a formula variable)
  5060   + ignores types, which can make HOL proofs fail
  5061   + rules must not require higher-order unification, e.g. apply_type in ZF
  5062     [message "Function Var's argument not a bound variable" relates to this]
  5063   + its proof strategy is more general but can actually be slower
  5064 
  5065 * substitution with equality assumptions no longer permutes other
  5066 assumptions;
  5067 
  5068 * minor changes in semantics of addafter (now called addaltern); renamed
  5069 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5070 (and access functions for it);
  5071 
  5072 * improved combination of classical reasoner and simplifier:
  5073   + functions for handling clasimpsets
  5074   + improvement of addss: now the simplifier is called _after_ the
  5075     safe steps.
  5076   + safe variant of addss called addSss: uses safe simplifications
  5077     _during_ the safe steps. It is more complete as it allows multiple
  5078     instantiations of unknowns (e.g. with slow_tac).
  5079 
  5080 *** Simplifier ***
  5081 
  5082 * added interface for simplification procedures (functions that
  5083 produce *proven* rewrite rules on the fly, depending on current
  5084 redex);
  5085 
  5086 * ordering on terms as parameter (used for ordered rewriting);
  5087 
  5088 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5089 
  5090 * the solver is now split into a safe and an unsafe part.
  5091 This should be invisible for the normal user, except that the
  5092 functions setsolver and addsolver have been renamed to setSolver and
  5093 addSolver; added safe_asm_full_simp_tac;
  5094 
  5095 
  5096 *** HOL ***
  5097 
  5098 * a generic induction tactic `induct_tac' which works for all datatypes and
  5099 also for type `nat';
  5100 
  5101 * a generic case distinction tactic `exhaust_tac' which works for all
  5102 datatypes and also for type `nat';
  5103 
  5104 * each datatype comes with a function `size';
  5105 
  5106 * patterns in case expressions allow tuple patterns as arguments to
  5107 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5108 
  5109 * primrec now also works with type nat;
  5110 
  5111 * recdef: a new declaration form, allows general recursive functions to be
  5112 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5113 
  5114 * the constant for negation has been renamed from "not" to "Not" to
  5115 harmonize with FOL, ZF, LK, etc.;
  5116 
  5117 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5118 infinite lists;
  5119 
  5120 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5121 
  5122 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5123 problems in commutative rings, using axiomatic type classes for + and *;
  5124 
  5125 * more examples in HOL/MiniML and HOL/Auth;
  5126 
  5127 * more default rewrite rules for quantifiers, union/intersection;
  5128 
  5129 * a new constant `arbitrary == @x.False';
  5130 
  5131 * HOLCF/IOA replaces old HOL/IOA;
  5132 
  5133 * HOLCF changes: derived all rules and arities
  5134   + axiomatic type classes instead of classes
  5135   + typedef instead of faking type definitions
  5136   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5137   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5138   + eliminated the types void, one, tr
  5139   + use unit lift and bool lift (with translations) instead of one and tr
  5140   + eliminated blift from Lift3.thy (use Def instead of blift)
  5141   all eliminated rules are derived as theorems --> no visible changes ;
  5142 
  5143 
  5144 *** ZF ***
  5145 
  5146 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5147 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5148 as ZF_cs addSIs [equalityI];
  5149 
  5150 
  5151 
  5152 New in Isabelle94-7 (November 96)
  5153 ---------------------------------
  5154 
  5155 * allowing negative levels (as offsets) in prlev and choplev;
  5156 
  5157 * super-linear speedup for large simplifications;
  5158 
  5159 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5160 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5161 FAIL); can suppress it using the command Delsimps (ex_simps @
  5162 all_simps); De Morgan laws are also now included, by default;
  5163 
  5164 * improved printing of ==>  :  ~:
  5165 
  5166 * new object-logic "Sequents" adds linear logic, while replacing LK
  5167 and Modal (thanks to Sara Kalvala);
  5168 
  5169 * HOL/Auth: correctness proofs for authentication protocols;
  5170 
  5171 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5172 examples on HOL/Auth);
  5173 
  5174 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5175 the rewriter and classical reasoner simultaneously;
  5176 
  5177 * function uresult no longer returns theorems in "standard" format;
  5178 regain previous version by: val uresult = standard o uresult;
  5179 
  5180 
  5181 
  5182 New in Isabelle94-6
  5183 -------------------
  5184 
  5185 * oracles -- these establish an interface between Isabelle and trusted
  5186 external reasoners, which may deliver results as theorems;
  5187 
  5188 * proof objects (in particular record all uses of oracles);
  5189 
  5190 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5191 
  5192 * "constdefs" section in theory files;
  5193 
  5194 * "primrec" section (HOL) no longer requires names;
  5195 
  5196 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5197 
  5198 
  5199 
  5200 New in Isabelle94-5
  5201 -------------------
  5202 
  5203 * reduced space requirements;
  5204 
  5205 * automatic HTML generation from theories;
  5206 
  5207 * theory files no longer require "..." (quotes) around most types;
  5208 
  5209 * new examples, including two proofs of the Church-Rosser theorem;
  5210 
  5211 * non-curried (1994) version of HOL is no longer distributed;
  5212 
  5213 
  5214 
  5215 New in Isabelle94-4
  5216 -------------------
  5217 
  5218 * greatly reduced space requirements;
  5219 
  5220 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5221 
  5222 * searchable theorem database (see the section "Retrieving theorems" on
  5223 page 8 of the Reference Manual);
  5224 
  5225 * new examples, including Grabczewski's monumental case study of the
  5226 Axiom of Choice;
  5227 
  5228 * The previous version of HOL renamed to Old_HOL;
  5229 
  5230 * The new version of HOL (previously called CHOL) uses a curried syntax
  5231 for functions.  Application looks like f a b instead of f(a,b);
  5232 
  5233 * Mutually recursive inductive definitions finally work in HOL;
  5234 
  5235 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5236 translates to the operator "split";
  5237 
  5238 
  5239 
  5240 New in Isabelle94-3
  5241 -------------------
  5242 
  5243 * new infix operator, addss, allowing the classical reasoner to
  5244 perform simplification at each step of its search.  Example:
  5245         fast_tac (cs addss ss)
  5246 
  5247 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5248 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5249 look like (a,b) instead of <a,b>;
  5250 
  5251 * PLEASE NOTE: CHOL will eventually replace HOL!
  5252 
  5253 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5254 It translates to the operator "split".  A new theory of integers is available;
  5255 
  5256 * In ZF, integer numerals now denote two's-complement binary integers.
  5257 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5258 
  5259 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5260 of the Axiom of Choice;
  5261 
  5262 
  5263 
  5264 New in Isabelle94-2
  5265 -------------------
  5266 
  5267 * Significantly faster resolution;
  5268 
  5269 * the different sections in a .thy file can now be mixed and repeated
  5270 freely;
  5271 
  5272 * Database of theorems for FOL, HOL and ZF.  New
  5273 commands including qed, qed_goal and bind_thm store theorems in the database.
  5274 
  5275 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5276 a given theory (thms_of), or find out what theory a theorem was proved in
  5277 (theory_of_thm);
  5278 
  5279 * Bugs fixed in the inductive definition and datatype packages;
  5280 
  5281 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5282 and HOL_dup_cs obsolete;
  5283 
  5284 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5285 have been removed;
  5286 
  5287 * Simpler definition of function space in ZF;
  5288 
  5289 * new results about cardinal and ordinal arithmetic in ZF;
  5290 
  5291 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5292 types;
  5293 
  5294 :mode=text:wrap=hard:maxLineLen=72:
  5295 
  5296 $Id$