NEWS
author wenzelm
Thu Mar 20 16:54:11 2008 +0100 (2008-03-20 ago)
changeset 26365 e6d3714b8853
parent 26355 9276633fdc24
child 26387 7807cbf7640f
permissions -rw-r--r--
fixed proof;
     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 * Instantiation target allows for simultaneous specification of class
    33 instance operations together with an instantiation proof.
    34 Type-checking phase allows to refer to class operations uniformly.
    35 See HOL/Complex/Complex.thy for an Isar example and
    36 HOL/Library/Eval.thy for an ML example.
    37 
    38 * Indexing of literal facts: be more serious about including only
    39 facts from the visible specification/proof context, but not the
    40 background context (locale etc.).  Affects `prop` notation and method
    41 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
    42 situations.
    43 
    44 
    45 *** HOL ***
    46 
    47 * Theory Product_Type: duplicated lemmas split_Pair_apply and injective_fst_snd
    48 removed, use split_eta and prod_eqI instead.  Renamed upd_fst to apfst and upd_snd
    49 to apsnd.  INCOMPATIBILITY.
    50 
    51 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
    52 the same name in theory Orderings:
    53 
    54   less_trans
    55   less_linear
    56   le_imp_less_or_eq
    57   le_less_trans
    58   less_le_trans
    59   less_not_sym
    60   less_asym
    61 
    62 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
    63 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
    64 and different variable names.
    65 
    66 * Library/Option_ord.thy: Canonical order on option type.
    67 
    68 * Library/RBT.thy: New theory of red-black trees, an efficient
    69 implementation of finite maps.
    70 
    71 * Library/Countable.thy: Type class for countable types.
    72 
    73 * Theory Int: The representation of numerals has changed.  The infix
    74 operator BIT and the bit datatype with constructors B0 and B1 have
    75 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
    76 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
    77 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
    78 accordingly.
    79 
    80 * Theory Nat: definition of <= and < on natural numbers no longer
    81 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
    82 le_def and less_def have disappeared.  Consider lemmas not_less
    83 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
    84 
    85 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
    86 (whose purpose mainly is for various fold_set functionals) have been
    87 abandoned in favour of the existing algebraic classes
    88 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
    89 lower_semilattice (resp. upper_semilattice) and linorder.
    90 INCOMPATIBILITY.
    91 
    92 * Theory Transitive_Closure: induct and cases rules now declare proper
    93 case_names ("base" and "step").  INCOMPATIBILITY.
    94 
    95 * Theorem Inductive.lfp_ordinal_induct generalized to complete
    96 lattices.  The form set-specific version is available as
    97 Inductive.lfp_ordinal_induct_set.
    98 
    99 * Theorems "power.simps" renamed to "power_int.simps".
   100 
   101 * Class semiring_div provides basic abstract properties of semirings
   102 with division and modulo operations.  Subsumes former class dvd_mod.
   103 
   104 * Merged theories IntDef, Numeral and IntArith into unified theory
   105 Int.  INCOMPATIBILITY.
   106 
   107 * Theory Library/Code_Index: type "index" now represents natural
   108 numbers rather than integers.  INCOMPATIBILITY.
   109 
   110 * New class "uminus" with operation "uminus" (split of from class
   111 "minus" which now only has operation "minus", binary).
   112 INCOMPATIBILITY.
   113 
   114 * New primrec package.  Specification syntax conforms in style to
   115 definition/function/....  No separate induction rule is provided.  The
   116 "primrec" command distinguishes old-style and new-style specifications
   117 by syntax.  The former primrec package is now named OldPrimrecPackage.
   118 When adjusting theories, beware: constants stemming from new-style
   119 primrec specifications have authentic syntax.
   120 
   121 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
   122 
   123 * Library/ListVector: new theory of arithmetic vector operations.
   124 
   125 * Constants "card", "internal_split", "option_map" now with authentic
   126 syntax.  INCOMPATIBILITY.
   127 
   128 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
   129 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
   130 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
   131 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
   132 Sup_set_def, le_def, less_def, option_map_def now with object
   133 equality.  INCOMPATIBILITY.
   134 
   135 * Method "induction_scheme" derives user-specified induction rules
   136 from wellfounded induction and completeness of patterns. This factors
   137 out some operations that are done internally by the function package
   138 and makes them available separately. See "HOL/ex/Induction_Scheme.thy"
   139 for examples,
   140 
   141 * Records. Removed K_record, and replaced it by pure lambda term
   142 %x. c. The simplifier setup is now more robust against eta expansion.
   143 INCOMPATIBILITY: in cases explicitly referring to K_record.
   144 
   145 * Metis prover is now an order of magnitude faster, and also works
   146 with multithreading.
   147 
   148 * Sledgehammer no longer produces structured proofs by default. To enable, 
   149 declare [[sledgehammer_full = true]]. Attributes reconstruction_modulus,  
   150 reconstruction_sorts renamed sledgehammer_modulus, sledgehammer_sorts. 
   151 INCOMPATIBILITY.
   152 
   153 *** ZF ***
   154 
   155 * Renamed theories:
   156 
   157   Datatype.thy  -> Datatype_ZF.thy
   158   Inductive.thy -> Inductive_ZF.thy
   159   Int.thy       -> Int_ZF.thy
   160   IntDiv.thy    -> IntDiv_ZF.thy
   161   Nat.thy       -> Nat_ZF.thy
   162   List.thy      -> List_ZF.thy
   163   Main.thy      -> Main_ZF.thy
   164 
   165  This is to allow to load both ZF and HOL in the same session.
   166 
   167  INCOMPATIBILITY: ZF theories that import individual theories below
   168  Main might need to be adapted. For compatibility, a new 
   169  "theory Main imports Main_ZF begin end" is provided, so if you just
   170  imported "Main", no changes are needed.
   171 
   172 
   173 *** ML ***
   174 
   175 * ML within Isar: antiquotation @{const name} or @{const
   176 name(typargs)} produces statically-checked Const term.
   177 
   178 * The ``print mode'' is now a thread-local value derived from a global
   179 template (the former print_mode reference), thus access becomes
   180 non-critical.  The global print_mode reference is for session
   181 management only; user-code should use print_mode_value,
   182 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
   183 
   184 * system/system_out provides a robust way to invoke external shell
   185 commands, with propagation of interrupts (after Poly/ML 5.2).  Do not
   186 use OS.Process.system etc. directly.
   187 
   188 
   189 *** System ***
   190 
   191 * System: removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the
   192 documented way of changing the user's settings is via
   193 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
   194 script.
   195 
   196 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
   197 in accordance with Proof General 3.7, which prefers GNU emacs.
   198 
   199 * Multithreading.max_threads := 0 refers to the number of actual CPU
   200 cores of the underlying machine, which is a good starting point for
   201 optimal performance tuning.  The corresponding usedir option -M allows
   202 "max" as an alias for "0".  WARNING: does not work on certain versions
   203 of Mac OS (with Poly/ML 5.1).
   204 
   205 * isatool tty runs Isabelle process with plain tty interaction;
   206 optional line editor may be specified via ISABELLE_LINE_EDITOR
   207 setting, the default settings attempt to locate "ledit" and "rlwrap".
   208 
   209 * isatool browser now works with Cygwin as well, using general
   210 "javapath" function defined in Isabelle process environment.
   211 
   212 * isabelle-process: non-ML sessions are run with "nice", to prevent
   213 Isabelle from flooding interactive front-ends (notably ProofGeneral /
   214 XEmacs).
   215 
   216 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   217 provides general wrapper for managing an Isabelle process in a robust
   218 fashion, with ``cooked'' output from stdin/stderr.
   219 
   220 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   221 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   222 
   223 
   224 
   225 New in Isabelle2007 (November 2007)
   226 -----------------------------------
   227 
   228 *** General ***
   229 
   230 * More uniform information about legacy features, notably a
   231 warning/error of "Legacy feature: ...", depending on the state of the
   232 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   233 legacy features will disappear eventually.
   234 
   235 * Theory syntax: the header format ``theory A = B + C:'' has been
   236 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   237 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   238 
   239 * Theory syntax: the old non-Isar theory file format has been
   240 discontinued altogether.  Note that ML proof scripts may still be used
   241 with Isar theories; migration is usually quite simple with the ML
   242 function use_legacy_bindings.  INCOMPATIBILITY.
   243 
   244 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   245 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   246 quotes.
   247 
   248 * Theory loader: be more serious about observing the static theory
   249 header specifications (including optional directories), but not the
   250 accidental file locations of previously successful loads.  The strict
   251 update policy of former update_thy is now already performed by
   252 use_thy, so the former has been removed; use_thys updates several
   253 theories simultaneously, just as 'imports' within a theory header
   254 specification, but without merging the results.  Potential
   255 INCOMPATIBILITY: may need to refine theory headers and commands
   256 ROOT.ML which depend on load order.
   257 
   258 * Theory loader: optional support for content-based file
   259 identification, instead of the traditional scheme of full physical
   260 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   261 (cf. the system manual).  The new scheme allows to work with
   262 non-finished theories in persistent session images, such that source
   263 files may be moved later on without requiring reloads.
   264 
   265 * Theory loader: old-style ML proof scripts being *attached* to a thy
   266 file (with the same base name as the theory) are considered a legacy
   267 feature, which will disappear eventually. Even now, the theory loader
   268 no longer maintains dependencies on such files.
   269 
   270 * Syntax: the scope for resolving ambiguities via type-inference is
   271 now limited to individual terms, instead of whole simultaneous
   272 specifications as before. This greatly reduces the complexity of the
   273 syntax module and improves flexibility by separating parsing and
   274 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
   275 'fixes' etc.) are required in rare situations.
   276 
   277 * Syntax: constants introduced by new-style packages ('definition',
   278 'abbreviation' etc.) are passed through the syntax module in
   279 ``authentic mode''. This means that associated mixfix annotations
   280 really stick to such constants, independently of potential name space
   281 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
   282 trees are represented slightly differently, may need to adapt syntax
   283 translations accordingly. Use CONST marker in 'translations' and
   284 @{const_syntax} antiquotation in 'parse_translation' etc.
   285 
   286 * Legacy goal package: reduced interface to the bare minimum required
   287 to keep existing proof scripts running.  Most other user-level
   288 functions are now part of the OldGoals structure, which is *not* open
   289 by default (consider isatool expandshort before open OldGoals).
   290 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   291 these tend to cause confusion about the actual goal (!) context being
   292 used here, which is not necessarily the same as the_context().
   293 
   294 * Command 'find_theorems': supports "*" wild-card in "name:"
   295 criterion; "with_dups" option.  Certain ProofGeneral versions might
   296 support a specific search form (see ProofGeneral/CHANGES).
   297 
   298 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   299 by default, which means that "prems" (and also "fixed variables") are
   300 suppressed from proof state output.  Note that the ProofGeneral
   301 settings mechanism allows to change and save options persistently, but
   302 older versions of Isabelle will fail to start up if a negative prems
   303 limit is imposed.
   304 
   305 * Local theory targets may be specified by non-nested blocks of
   306 ``context/locale/class ... begin'' followed by ``end''.  The body may
   307 contain definitions, theorems etc., including any derived mechanism
   308 that has been implemented on top of these primitives.  This concept
   309 generalizes the existing ``theorem (in ...)'' towards more versatility
   310 and scalability.
   311 
   312 * Proof General interface: proper undo of final 'end' command;
   313 discontinued Isabelle/classic mode (ML proof scripts).
   314 
   315 
   316 *** Document preparation ***
   317 
   318 * Added antiquotation @{theory name} which prints the given name,
   319 after checking that it refers to a valid ancestor theory in the
   320 current context.
   321 
   322 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   323 check the given source text as ML type/structure, printing verbatim.
   324 
   325 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   326 "c args == rhs" given in the current context.  (Any number of
   327 arguments may be given on the LHS.)
   328 
   329 
   330 *** Pure ***
   331 
   332 * The 'class' package offers a combination of axclass and locale to
   333 achieve Haskell-like type classes in Isabelle.  Definitions and
   334 theorems within a class context produce both relative results (with
   335 implicit parameters according to the locale context), and polymorphic
   336 constants with qualified polymorphism (according to the class
   337 context).  Within the body context of a 'class' target, a separate
   338 syntax layer ("user space type system") takes care of converting
   339 between global polymorphic consts and internal locale representation.
   340 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   341 "isatool doc classes" provides a tutorial.
   342 
   343 * Generic code generator framework allows to generate executable
   344 code for ML and Haskell (including Isabelle classes).  A short usage
   345 sketch:
   346 
   347     internal compilation:
   348         export_code <list of constants (term syntax)> in SML
   349     writing SML code to a file:
   350         export_code <list of constants (term syntax)> in SML <filename>
   351     writing OCaml code to a file:
   352         export_code <list of constants (term syntax)> in OCaml <filename>
   353     writing Haskell code to a bunch of files:
   354         export_code <list of constants (term syntax)> in Haskell <filename>
   355 
   356     evaluating closed propositions to True/False using code generation:
   357         method ``eval''
   358 
   359 Reasonable default setup of framework in HOL.
   360 
   361 Theorem attributs for selecting and transforming function equations theorems:
   362 
   363     [code fun]:        select a theorem as function equation for a specific constant
   364     [code fun del]:    deselect a theorem as function equation for a specific constant
   365     [code inline]:     select an equation theorem for unfolding (inlining) in place
   366     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   367 
   368 User-defined serializations (target in {SML, OCaml, Haskell}):
   369 
   370     code_const <and-list of constants (term syntax)>
   371       {(target) <and-list of const target syntax>}+
   372 
   373     code_type <and-list of type constructors>
   374       {(target) <and-list of type target syntax>}+
   375 
   376     code_instance <and-list of instances>
   377       {(target)}+
   378         where instance ::= <type constructor> :: <class>
   379 
   380     code_class <and_list of classes>
   381       {(target) <and-list of class target syntax>}+
   382         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   383 
   384 code_instance and code_class only are effective to target Haskell.
   385 
   386 For example usage see src/HOL/ex/Codegenerator.thy and
   387 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   388 generation from Isabelle/HOL theories is available via "isatool doc
   389 codegen".
   390 
   391 * Code generator: consts in 'consts_code' Isar commands are now
   392 referred to by usual term syntax (including optional type
   393 annotations).
   394 
   395 * Command 'no_translations' removes translation rules from theory
   396 syntax.
   397 
   398 * Overloaded definitions are now actually checked for acyclic
   399 dependencies.  The overloading scheme is slightly more general than
   400 that of Haskell98, although Isabelle does not demand an exact
   401 correspondence to type class and instance declarations.
   402 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   403 exotic versions of overloading -- at the discretion of the user!
   404 
   405 Polymorphic constants are represented via type arguments, i.e. the
   406 instantiation that matches an instance against the most general
   407 declaration given in the signature.  For example, with the declaration
   408 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   409 as c(nat).  Overloading is essentially simultaneous structural
   410 recursion over such type arguments.  Incomplete specification patterns
   411 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   412 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   413 Command 'print_theory' outputs the normalized system of recursive
   414 equations, see section "definitions".
   415 
   416 * Configuration options are maintained within the theory or proof
   417 context (with name and type bool/int/string), providing a very simple
   418 interface to a poor-man's version of general context data.  Tools may
   419 declare options in ML (e.g. using Attrib.config_int) and then refer to
   420 these values using Config.get etc.  Users may change options via an
   421 associated attribute of the same name.  This form of context
   422 declaration works particularly well with commands 'declare' or
   423 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   424 very easy to avoid global references, which would not observe Isar
   425 toplevel undo/redo and fail to work with multithreading.
   426 
   427 Various global ML references of Pure and HOL have been turned into
   428 configuration options:
   429 
   430   Unify.search_bound		unify_search_bound
   431   Unify.trace_bound		unify_trace_bound
   432   Unify.trace_simp		unify_trace_simp
   433   Unify.trace_types		unify_trace_types
   434   Simplifier.simp_depth_limit	simp_depth_limit
   435   Blast.depth_limit		blast_depth_limit
   436   DatatypeProp.dtK		datatype_distinctness_limit
   437   fast_arith_neq_limit  	fast_arith_neq_limit
   438   fast_arith_split_limit	fast_arith_split_limit
   439 
   440 * Named collections of theorems may be easily installed as context
   441 data using the functor NamedThmsFun (see also
   442 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   443 attributes; there is also a toplevel print command.  This facility is
   444 just a common case of general context data, which is the preferred way
   445 for anything more complex than just a list of facts in canonical
   446 order.
   447 
   448 * Isar: command 'declaration' augments a local theory by generic
   449 declaration functions written in ML.  This enables arbitrary content
   450 being added to the context, depending on a morphism that tells the
   451 difference of the original declaration context wrt. the application
   452 context encountered later on.
   453 
   454 * Isar: proper interfaces for simplification procedures.  Command
   455 'simproc_setup' declares named simprocs (with match patterns, and body
   456 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   457 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   458 
   459 * Isar: an extra pair of brackets around attribute declarations
   460 abbreviates a theorem reference involving an internal dummy fact,
   461 which will be ignored later --- only the effect of the attribute on
   462 the background context will persist.  This form of in-place
   463 declarations is particularly useful with commands like 'declare' and
   464 'using', for example ``have A using [[simproc a]] by simp''.
   465 
   466 * Isar: method "assumption" (and implicit closing of subproofs) now
   467 takes simple non-atomic goal assumptions into account: after applying
   468 an assumption as a rule the resulting subgoals are solved by atomic
   469 assumption steps.  This is particularly useful to finish 'obtain'
   470 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   471 without referring to the original premise "!!x. P x ==> thesis" in the
   472 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   473 more permissive.
   474 
   475 * Isar: implicit use of prems from the Isar proof context is
   476 considered a legacy feature.  Common applications like ``have A .''
   477 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   478 referencing facts explicitly here improves readability and
   479 maintainability of proof texts.
   480 
   481 * Isar: improper proof element 'guess' is like 'obtain', but derives
   482 the obtained context from the course of reasoning!  For example:
   483 
   484   assume "EX x y. A x & B y"   -- "any previous fact"
   485   then guess x and y by clarify
   486 
   487 This technique is potentially adventurous, depending on the facts and
   488 proof tools being involved here.
   489 
   490 * Isar: known facts from the proof context may be specified as literal
   491 propositions, using ASCII back-quote syntax.  This works wherever
   492 named facts used to be allowed so far, in proof commands, proof
   493 methods, attributes etc.  Literal facts are retrieved from the context
   494 according to unification of type and term parameters.  For example,
   495 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   496 theorems in the current context, then these are valid literal facts:
   497 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   498 
   499 There is also a proof method "fact" which does the same composition
   500 for explicit goal states, e.g. the following proof texts coincide with
   501 certain special cases of literal facts:
   502 
   503   have "A" by fact                 ==  note `A`
   504   have "A ==> B" by fact           ==  note `A ==> B`
   505   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   506   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   507 
   508 * Isar: ":" (colon) is no longer a symbolic identifier character in
   509 outer syntax.  Thus symbolic identifiers may be used without
   510 additional white space in declarations like this: ``assume *: A''.
   511 
   512 * Isar: 'print_facts' prints all local facts of the current context,
   513 both named and unnamed ones.
   514 
   515 * Isar: 'def' now admits simultaneous definitions, e.g.:
   516 
   517   def x == "t" and y == "u"
   518 
   519 * Isar: added command 'unfolding', which is structurally similar to
   520 'using', but affects both the goal state and facts by unfolding given
   521 rewrite rules.  Thus many occurrences of the 'unfold' method or
   522 'unfolded' attribute may be replaced by first-class proof text.
   523 
   524 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   525 and command 'unfolding' now all support object-level equalities
   526 (potentially conditional).  The underlying notion of rewrite rule is
   527 analogous to the 'rule_format' attribute, but *not* that of the
   528 Simplifier (which is usually more generous).
   529 
   530 * Isar: the new attribute [rotated n] (default n = 1) rotates the
   531 premises of a theorem by n. Useful in conjunction with drule.
   532 
   533 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   534 method expression within a sandbox consisting of the first N
   535 sub-goals, which need to exist.  For example, ``simp_all [3]''
   536 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   537 simplifies all new goals that emerge from applying rule foo to the
   538 originally first one.
   539 
   540 * Isar: schematic goals are no longer restricted to higher-order
   541 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   542 expected.
   543 
   544 * Isar: the conclusion of a long theorem statement is now either
   545 'shows' (a simultaneous conjunction, as before), or 'obtains'
   546 (essentially a disjunction of cases with local parameters and
   547 assumptions).  The latter allows to express general elimination rules
   548 adequately; in this notation common elimination rules look like this:
   549 
   550   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   551     assumes "EX x. P x"
   552     obtains x where "P x"
   553 
   554   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   555     assumes "A & B"
   556     obtains A and B
   557 
   558   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   559     assumes "A | B"
   560     obtains
   561       A
   562     | B
   563 
   564 The subsequent classical rules even refer to the formal "thesis"
   565 explicitly:
   566 
   567   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   568     obtains "~ thesis"
   569 
   570   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   571     obtains "thesis ==> something"
   572 
   573 The actual proof of an 'obtains' statement is analogous to that of the
   574 Isar proof element 'obtain', only that there may be several cases.
   575 Optional case names may be specified in parentheses; these will be
   576 available both in the present proof and as annotations in the
   577 resulting rule, for later use with the 'cases' method (cf. attribute
   578 case_names).
   579 
   580 * Isar: the assumptions of a long theorem statement are available as
   581 "assms" fact in the proof context.  This is more appropriate than the
   582 (historical) "prems", which refers to all assumptions of the current
   583 context, including those from the target locale, proof body etc.
   584 
   585 * Isar: 'print_statement' prints theorems from the current theory or
   586 proof context in long statement form, according to the syntax of a
   587 top-level lemma.
   588 
   589 * Isar: 'obtain' takes an optional case name for the local context
   590 introduction rule (default "that").
   591 
   592 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   593 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   594 to occur.
   595 
   596 * Pure: syntax "CONST name" produces a fully internalized constant
   597 according to the current context.  This is particularly useful for
   598 syntax translations that should refer to internal constant
   599 representations independently of name spaces.
   600 
   601 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   602 instead of "FOO ". This allows multiple binder declarations to coexist
   603 in the same context.  INCOMPATIBILITY.
   604 
   605 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   606 primitive that also works in a locale context (both for constants and
   607 fixed variables). Type declaration and internal syntactic representation
   608 of given constants retrieved from the context. Likewise, the
   609 'no_notation' command allows to remove given syntax annotations from the
   610 current context.
   611 
   612 * Isar/locales: new derived specification elements 'axiomatization',
   613 'definition', 'abbreviation', which support type-inference, admit
   614 object-level specifications (equality, equivalence).  See also the
   615 isar-ref manual.  Examples:
   616 
   617   axiomatization
   618     eq  (infix "===" 50) where
   619     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   620 
   621   definition "f x y = x + y + 1"
   622   definition g where "g x = f x x"
   623 
   624   abbreviation
   625     neq  (infix "=!=" 50) where
   626     "x =!= y == ~ (x === y)"
   627 
   628 These specifications may be also used in a locale context.  Then the
   629 constants being introduced depend on certain fixed parameters, and the
   630 constant name is qualified by the locale base name.  An internal
   631 abbreviation takes care for convenient input and output, making the
   632 parameters implicit and using the original short name.  See also
   633 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   634 entities from a monomorphic theory.
   635 
   636 Presently, abbreviations are only available 'in' a target locale, but
   637 not inherited by general import expressions.  Also note that
   638 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   639 'translations' in common applications.  The "no_abbrevs" print mode
   640 prevents folding of abbreviations in term output.
   641 
   642 Concrete syntax is attached to specified constants in internal form,
   643 independently of name spaces.  The parse tree representation is
   644 slightly different -- use 'notation' instead of raw 'syntax', and
   645 'translations' with explicit "CONST" markup to accommodate this.
   646 
   647 * Pure/Isar: unified syntax for new-style specification mechanisms
   648 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
   649 full type inference and dummy patterns ("_").  For example:
   650 
   651   definition "K x _ = x"
   652 
   653   inductive conj for A B
   654   where "A ==> B ==> conj A B"
   655 
   656 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   657 the current context.  Print mode "no_abbrevs" prevents inversion of
   658 abbreviations on output.
   659 
   660 * Isar/locales: improved parameter handling: use of locales "var" and
   661 "struct" no longer necessary; - parameter renamings are no longer
   662 required to be injective.  For example, this allows to define
   663 endomorphisms as locale endom = homom mult mult h.
   664 
   665 * Isar/locales: changed the way locales with predicates are defined.
   666 Instead of accumulating the specification, the imported expression is
   667 now an interpretation.  INCOMPATIBILITY: different normal form of
   668 locale expressions.  In particular, in interpretations of locales with
   669 predicates, goals repesenting already interpreted fragments are not
   670 removed automatically.  Use methods `intro_locales' and
   671 `unfold_locales'; see below.
   672 
   673 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   674 provide backward reasoning on locales predicates.  The methods are
   675 aware of interpretations and discharge corresponding goals.
   676 `intro_locales' is less aggressive then `unfold_locales' and does not
   677 unfold predicates to assumptions.
   678 
   679 * Isar/locales: the order in which locale fragments are accumulated
   680 has changed.  This enables to override declarations from fragments due
   681 to interpretations -- for example, unwanted simp rules.
   682 
   683 * Isar/locales: interpretation in theories and proof contexts has been
   684 extended.  One may now specify (and prove) equations, which are
   685 unfolded in interpreted theorems.  This is useful for replacing
   686 defined concepts (constants depending on locale parameters) by
   687 concepts already existing in the target context.  Example:
   688 
   689   interpretation partial_order ["op <= :: [int, int] => bool"]
   690     where "partial_order.less (op <=) (x::int) y = (x < y)"
   691 
   692 Typically, the constant `partial_order.less' is created by a
   693 definition specification element in the context of locale
   694 partial_order.
   695 
   696 * Method "induct": improved internal context management to support
   697 local fixes and defines on-the-fly. Thus explicit meta-level
   698 connectives !!  and ==> are rarely required anymore in inductive goals
   699 (using object-logic connectives for this purpose has been long
   700 obsolete anyway). Common proof patterns are explained in
   701 src/HOL/Induct/Common_Patterns.thy, see also
   702 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
   703 examples.
   704 
   705 * Method "induct": improved handling of simultaneous goals. Instead of
   706 introducing object-level conjunction, the statement is now split into
   707 several conclusions, while the corresponding symbolic cases are nested
   708 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
   709 see src/HOL/Induct/Common_Patterns.thy, for example.
   710 
   711 * Method "induct": mutual induction rules are now specified as a list
   712 of rule sharing the same induction cases. HOL packages usually provide
   713 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
   714 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
   715 mutual induction rules differently, i.e. like this:
   716 
   717   (induct rule: foo_bar.inducts)
   718   (induct set: foo bar)
   719   (induct pred: foo bar)
   720   (induct type: foo bar)
   721 
   722 The ML function ProjectRule.projections turns old-style rules into the
   723 new format.
   724 
   725 * Method "coinduct": dual of induction, see
   726 src/HOL/Library/Coinductive_List.thy for various examples.
   727 
   728 * Method "cases", "induct", "coinduct": the ``(open)'' option is
   729 considered a legacy feature.
   730 
   731 * Attribute "symmetric" produces result with standardized schematic
   732 variables (index 0).  Potential INCOMPATIBILITY.
   733 
   734 * Simplifier: by default the simplifier trace only shows top level
   735 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   736 default. Thus there is less danger of being flooded by the trace. The
   737 trace indicates where parts have been suppressed.
   738   
   739 * Provers/classical: removed obsolete classical version of elim_format
   740 attribute; classical elim/dest rules are now treated uniformly when
   741 manipulating the claset.
   742 
   743 * Provers/classical: stricter checks to ensure that supplied intro,
   744 dest and elim rules are well-formed; dest and elim rules must have at
   745 least one premise.
   746 
   747 * Provers/classical: attributes dest/elim/intro take an optional
   748 weight argument for the rule (just as the Pure versions).  Weights are
   749 ignored by automated tools, but determine the search order of single
   750 rule steps.
   751 
   752 * Syntax: input syntax now supports dummy variable binding "%_. b",
   753 where the body does not mention the bound variable.  Note that dummy
   754 patterns implicitly depend on their context of bounds, which makes
   755 "{_. _}" match any set comprehension as expected.  Potential
   756 INCOMPATIBILITY -- parse translations need to cope with syntactic
   757 constant "_idtdummy" in the binding position.
   758 
   759 * Syntax: removed obsolete syntactic constant "_K" and its associated
   760 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   761 for example "A -> B" => "Pi A (%_. B)".
   762 
   763 * Pure: 'class_deps' command visualizes the subclass relation, using
   764 the graph browser tool.
   765 
   766 * Pure: 'print_theory' now suppresses certain internal declarations by
   767 default; use '!' option for full details.
   768 
   769 
   770 *** HOL ***
   771 
   772 * Method "metis" proves goals by applying the Metis general-purpose
   773 resolution prover (see also http://gilith.com/software/metis/).
   774 Examples are in the directory MetisExamples.  WARNING: the
   775 Isabelle/HOL-Metis integration does not yet work properly with
   776 multi-threading.
   777   
   778 * Command 'sledgehammer' invokes external automatic theorem provers as
   779 background processes.  It generates calls to the "metis" method if
   780 successful. These can be pasted into the proof.  Users do not have to
   781 wait for the automatic provers to return.  WARNING: does not really
   782 work with multi-threading.
   783 
   784 * New "auto_quickcheck" feature tests outermost goal statements for
   785 potential counter-examples.  Controlled by ML references
   786 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
   787 5000 milliseconds).  Fails silently if statements is outside of
   788 executable fragment, or any other codgenerator problem occurs.
   789 
   790 * New constant "undefined" with axiom "undefined x = undefined".
   791 
   792 * Added class "HOL.eq", allowing for code generation with polymorphic
   793 equality.
   794 
   795 * Some renaming of class constants due to canonical name prefixing in
   796 the new 'class' package:
   797 
   798     HOL.abs ~> HOL.abs_class.abs
   799     HOL.divide ~> HOL.divide_class.divide
   800     0 ~> HOL.zero_class.zero
   801     1 ~> HOL.one_class.one
   802     op + ~> HOL.plus_class.plus
   803     op - ~> HOL.minus_class.minus
   804     uminus ~> HOL.minus_class.uminus
   805     op * ~> HOL.times_class.times
   806     op < ~> HOL.ord_class.less
   807     op <= > HOL.ord_class.less_eq
   808     Nat.power ~> Power.power_class.power
   809     Nat.size ~> Nat.size_class.size
   810     Numeral.number_of ~> Numeral.number_class.number_of
   811     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
   812     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
   813     Orderings.min ~> Orderings.ord_class.min
   814     Orderings.max ~> Orderings.ord_class.max
   815     Divides.op div ~> Divides.div_class.div
   816     Divides.op mod ~> Divides.div_class.mod
   817     Divides.op dvd ~> Divides.div_class.dvd
   818 
   819 INCOMPATIBILITY.  Adaptions may be required in the following cases:
   820 
   821 a) User-defined constants using any of the names "plus", "minus",
   822 "times", "less" or "less_eq". The standard syntax translations for
   823 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
   824 names.
   825 
   826 b) Variables named "plus", "minus", "times", "less", "less_eq"
   827 INCOMPATIBILITY: use more specific names.
   828 
   829 c) Permutative equations (e.g. "a + b = b + a")
   830 Since the change of names also changes the order of terms, permutative
   831 rewrite rules may get applied in a different order. Experience shows
   832 that this is rarely the case (only two adaptions in the whole Isabelle
   833 distribution).  INCOMPATIBILITY: rewrite proofs
   834 
   835 d) ML code directly refering to constant names
   836 This in general only affects hand-written proof tactics, simprocs and
   837 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
   838 Consider using @{const_name} antiquotation.
   839 
   840 * New class "default" with associated constant "default".
   841 
   842 * Function "sgn" is now overloaded and available on int, real, complex
   843 (and other numeric types), using class "sgn".  Two possible defs of
   844 sgn are given as equational assumptions in the classes sgn_if and
   845 sgn_div_norm; ordered_idom now also inherits from sgn_if.
   846 INCOMPATIBILITY.
   847 
   848 * Locale "partial_order" now unified with class "order" (cf. theory
   849 Orderings), added parameter "less".  INCOMPATIBILITY.
   850 
   851 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
   852 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
   853 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
   854 
   855 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
   856 changed order of proof goals in instance proofs.
   857 
   858 * The transitivity reasoner for partial and linear orders is set up
   859 for classes "order" and "linorder".  Instances of the reasoner are available
   860 in all contexts importing or interpreting the corresponding locales.
   861 Method "order" invokes the reasoner separately; the reasoner
   862 is also integrated with the Simplifier as a solver.  Diagnostic
   863 command 'print_orders' shows the available instances of the reasoner
   864 in the current context.
   865 
   866 * Localized monotonicity predicate in theory "Orderings"; integrated
   867 lemmas max_of_mono and min_of_mono with this predicate.
   868 INCOMPATIBILITY.
   869 
   870 * Formulation of theorem "dense" changed slightly due to integration
   871 with new class dense_linear_order.
   872 
   873 * Uniform lattice theory development in HOL.
   874 
   875     constants "meet" and "join" now named "inf" and "sup"
   876     constant "Meet" now named "Inf"
   877 
   878     classes "meet_semilorder" and "join_semilorder" now named
   879       "lower_semilattice" and "upper_semilattice"
   880     class "lorder" now named "lattice"
   881     class "comp_lat" now named "complete_lattice"
   882 
   883     Instantiation of lattice classes allows explicit definitions
   884     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
   885 
   886   INCOMPATIBILITY.  Theorem renames:
   887 
   888     meet_left_le            ~> inf_le1
   889     meet_right_le           ~> inf_le2
   890     join_left_le            ~> sup_ge1
   891     join_right_le           ~> sup_ge2
   892     meet_join_le            ~> inf_sup_ord
   893     le_meetI                ~> le_infI
   894     join_leI                ~> le_supI
   895     le_meet                 ~> le_inf_iff
   896     le_join                 ~> ge_sup_conv
   897     meet_idempotent         ~> inf_idem
   898     join_idempotent         ~> sup_idem
   899     meet_comm               ~> inf_commute
   900     join_comm               ~> sup_commute
   901     meet_leI1               ~> le_infI1
   902     meet_leI2               ~> le_infI2
   903     le_joinI1               ~> le_supI1
   904     le_joinI2               ~> le_supI2
   905     meet_assoc              ~> inf_assoc
   906     join_assoc              ~> sup_assoc
   907     meet_left_comm          ~> inf_left_commute
   908     meet_left_idempotent    ~> inf_left_idem
   909     join_left_comm          ~> sup_left_commute
   910     join_left_idempotent    ~> sup_left_idem
   911     meet_aci                ~> inf_aci
   912     join_aci                ~> sup_aci
   913     le_def_meet             ~> le_iff_inf
   914     le_def_join             ~> le_iff_sup
   915     join_absorp2            ~> sup_absorb2
   916     join_absorp1            ~> sup_absorb1
   917     meet_absorp1            ~> inf_absorb1
   918     meet_absorp2            ~> inf_absorb2
   919     meet_join_absorp        ~> inf_sup_absorb
   920     join_meet_absorp        ~> sup_inf_absorb
   921     distrib_join_le         ~> distrib_sup_le
   922     distrib_meet_le         ~> distrib_inf_le
   923 
   924     add_meet_distrib_left   ~> add_inf_distrib_left
   925     add_join_distrib_left   ~> add_sup_distrib_left
   926     is_join_neg_meet        ~> is_join_neg_inf
   927     is_meet_neg_join        ~> is_meet_neg_sup
   928     add_meet_distrib_right  ~> add_inf_distrib_right
   929     add_join_distrib_right  ~> add_sup_distrib_right
   930     add_meet_join_distribs  ~> add_sup_inf_distribs
   931     join_eq_neg_meet        ~> sup_eq_neg_inf
   932     meet_eq_neg_join        ~> inf_eq_neg_sup
   933     add_eq_meet_join        ~> add_eq_inf_sup
   934     meet_0_imp_0            ~> inf_0_imp_0
   935     join_0_imp_0            ~> sup_0_imp_0
   936     meet_0_eq_0             ~> inf_0_eq_0
   937     join_0_eq_0             ~> sup_0_eq_0
   938     neg_meet_eq_join        ~> neg_inf_eq_sup
   939     neg_join_eq_meet        ~> neg_sup_eq_inf
   940     join_eq_if              ~> sup_eq_if
   941 
   942     mono_meet               ~> mono_inf
   943     mono_join               ~> mono_sup
   944     meet_bool_eq            ~> inf_bool_eq
   945     join_bool_eq            ~> sup_bool_eq
   946     meet_fun_eq             ~> inf_fun_eq
   947     join_fun_eq             ~> sup_fun_eq
   948     meet_set_eq             ~> inf_set_eq
   949     join_set_eq             ~> sup_set_eq
   950     meet1_iff               ~> inf1_iff
   951     meet2_iff               ~> inf2_iff
   952     meet1I                  ~> inf1I
   953     meet2I                  ~> inf2I
   954     meet1D1                 ~> inf1D1
   955     meet2D1                 ~> inf2D1
   956     meet1D2                 ~> inf1D2
   957     meet2D2                 ~> inf2D2
   958     meet1E                  ~> inf1E
   959     meet2E                  ~> inf2E
   960     join1_iff               ~> sup1_iff
   961     join2_iff               ~> sup2_iff
   962     join1I1                 ~> sup1I1
   963     join2I1                 ~> sup2I1
   964     join1I1                 ~> sup1I1
   965     join2I2                 ~> sup1I2
   966     join1CI                 ~> sup1CI
   967     join2CI                 ~> sup2CI
   968     join1E                  ~> sup1E
   969     join2E                  ~> sup2E
   970 
   971     is_meet_Meet            ~> is_meet_Inf
   972     Meet_bool_def           ~> Inf_bool_def
   973     Meet_fun_def            ~> Inf_fun_def
   974     Meet_greatest           ~> Inf_greatest
   975     Meet_lower              ~> Inf_lower
   976     Meet_set_def            ~> Inf_set_def
   977 
   978     Sup_def                 ~> Sup_Inf
   979     Sup_bool_eq             ~> Sup_bool_def
   980     Sup_fun_eq              ~> Sup_fun_def
   981     Sup_set_eq              ~> Sup_set_def
   982 
   983     listsp_meetI            ~> listsp_infI
   984     listsp_meet_eq          ~> listsp_inf_eq
   985 
   986     meet_min                ~> inf_min
   987     join_max                ~> sup_max
   988 
   989 * Added syntactic class "size"; overloaded constant "size" now has
   990 type "'a::size ==> bool"
   991 
   992 * Internal reorganisation of `size' of datatypes: size theorems
   993 "foo.size" are no longer subsumed by "foo.simps" (but are still
   994 simplification rules by default!); theorems "prod.size" now named
   995 "*.size".
   996 
   997 * Class "div" now inherits from class "times" rather than "type".
   998 INCOMPATIBILITY.
   999 
  1000 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1001 Linorder etc.  have disappeared; operations defined in terms of
  1002 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1003 
  1004 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1005 
  1006 * HOL-Word: New extensive library and type for generic, fixed size
  1007 machine words, with arithemtic, bit-wise, shifting and rotating
  1008 operations, reflection into int, nat, and bool lists, automation for
  1009 linear arithmetic (by automatic reflection into nat or int), including
  1010 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1011 arithmetic type classes, supporting automatic simplification of
  1012 numerals on all operations.
  1013 
  1014 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1015 
  1016 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1017 
  1018 * Code generator library theories:
  1019   - Code_Integer represents HOL integers by big integer literals in target
  1020     languages.
  1021   - Code_Char represents HOL characters by character literals in target
  1022     languages.
  1023   - Code_Char_chr like Code_Char, but also offers treatment of character
  1024     codes; includes Code_Integer.
  1025   - Executable_Set allows to generate code for finite sets using lists.
  1026   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1027     denominator).
  1028   - Executable_Real implements a subset of real numbers, namly those
  1029     representable by rational numbers.
  1030   - Efficient_Nat implements natural numbers by integers, which in general will
  1031     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1032     includes Code_Integer.
  1033   - Code_Index provides an additional datatype index which is mapped to
  1034     target-language built-in integers.
  1035   - Code_Message provides an additional datatype message_string which is isomorphic to
  1036     strings; messages are mapped to target-language strings.
  1037 
  1038 * New package for inductive predicates
  1039 
  1040   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1041 
  1042     inductive
  1043       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1044       for z_1 :: U_1 and ... and z_n :: U_m
  1045     where
  1046       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1047     | ...
  1048 
  1049   with full support for type-inference, rather than
  1050 
  1051     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1052 
  1053     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1054     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1055 
  1056     inductive "s z_1 ... z_m"
  1057     intros
  1058       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1059       ...
  1060 
  1061   For backward compatibility, there is a wrapper allowing inductive
  1062   sets to be defined with the new package via
  1063 
  1064     inductive_set
  1065       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1066       for z_1 :: U_1 and ... and z_n :: U_m
  1067     where
  1068       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1069     | ...
  1070 
  1071   or
  1072 
  1073     inductive_set
  1074       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1075       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1076       for z_1 :: U_1 and ... and z_n :: U_m
  1077     where
  1078       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1079     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1080     | ...
  1081 
  1082   if the additional syntax "p ..." is required.
  1083 
  1084   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1085   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1086 
  1087   INCOMPATIBILITIES:
  1088 
  1089   - Since declaration and definition of inductive sets or predicates
  1090     is no longer separated, abbreviations involving the newly
  1091     introduced sets or predicates must be specified together with the
  1092     introduction rules after the 'where' keyword (see above), rather
  1093     than before the actual inductive definition.
  1094 
  1095   - The variables in induction and elimination rules are now
  1096     quantified in the order of their occurrence in the introduction
  1097     rules, rather than in alphabetical order. Since this may break
  1098     some proofs, these proofs either have to be repaired, e.g. by
  1099     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1100     statements of the form
  1101 
  1102       case (rule_i a_i_1 ... a_i_{k_i})
  1103 
  1104     or the old order of quantification has to be restored by explicitly adding
  1105     meta-level quantifiers in the introduction rules, i.e.
  1106 
  1107       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1108 
  1109   - The format of the elimination rules is now
  1110 
  1111       p z_1 ... z_m x_1 ... x_n ==>
  1112         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1113         ==> ... ==> P
  1114 
  1115     for predicates and
  1116 
  1117       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1118         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1119         ==> ... ==> P
  1120 
  1121     for sets rather than
  1122 
  1123       x : s z_1 ... z_m ==>
  1124         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1125         ==> ... ==> P
  1126 
  1127     This may require terms in goals to be expanded to n-tuples
  1128     (e.g. using case_tac or simplification with the split_paired_all
  1129     rule) before the above elimination rule is applicable.
  1130 
  1131   - The elimination or case analysis rules for (mutually) inductive
  1132     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1133     list of rules "p_1_..._p_k.elims" is no longer available.
  1134 
  1135 * New package "function"/"fun" for general recursive functions,
  1136 supporting mutual and nested recursion, definitions in local contexts,
  1137 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1138 for small examples, and the separate tutorial on the function
  1139 package. The old recdef "package" is still available as before, but
  1140 users are encouraged to use the new package.
  1141 
  1142 * Method "lexicographic_order" automatically synthesizes termination
  1143 relations as lexicographic combinations of size measures. 
  1144 
  1145 * Case-expressions allow arbitrary constructor-patterns (including
  1146 "_") and take their order into account, like in functional
  1147 programming.  Internally, this is translated into nested
  1148 case-expressions; missing cases are added and mapped to the predefined
  1149 constant "undefined". In complicated cases printing may no longer show
  1150 the original input but the internal form. Lambda-abstractions allow
  1151 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1152 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1153 variable.
  1154 
  1155 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1156 is an abbreviation for "of_nat :: nat => int". The simplification
  1157 rules for "of_nat" have been changed to work like "int" did
  1158 previously.  Potential INCOMPATIBILITY:
  1159   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1160   - of_nat_diff and of_nat_mult are no longer default simp rules
  1161 
  1162 * Method "algebra" solves polynomial equations over (semi)rings using
  1163 Groebner bases. The (semi)ring structure is defined by locales and the
  1164 tool setup depends on that generic context. Installing the method for
  1165 a specific type involves instantiating the locale and possibly adding
  1166 declarations for computation on the coefficients.  The method is
  1167 already instantiated for natural numbers and for the axiomatic class
  1168 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1169 CALCULEMUS 2007 for the general principles underlying this
  1170 architecture of context-aware proof-tools.
  1171 
  1172 * Method "ferrack" implements quantifier elimination over
  1173 special-purpose dense linear orders using locales (analogous to
  1174 "algebra"). The method is already installed for class
  1175 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1176 rat, etc.
  1177 
  1178 * Former constant "List.op @" now named "List.append".  Use ML
  1179 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1180 circumvent possible incompatibilities when working on ML level.
  1181 
  1182 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1183 
  1184 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1185 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1186 
  1187 * New syntax for Haskell-like list comprehension (input only), eg.
  1188 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1189 
  1190 * The special syntax for function "filter" has changed from [x :
  1191 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1192 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1193 
  1194 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1195 defined on nat only, as an abbreviation for [a..<Suc b]
  1196 INCOMPATIBILITY.
  1197 
  1198 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1199 
  1200 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1201 
  1202 * New lemma collection field_simps (an extension of ring_simps) for
  1203 manipulating (in)equations involving division. Multiplies with all
  1204 denominators that can be proved to be non-zero (in equations) or
  1205 positive/negative (in inequations).
  1206 
  1207 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1208 have been improved and renamed to ring_simps, group_simps and
  1209 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1210 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1211 
  1212 * Theory Library/Commutative_Ring: switched from recdef to function
  1213 package; constants add, mul, pow now curried.  Infix syntax for
  1214 algebraic operations.
  1215 
  1216 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1217 INCOMPATIBILITY.
  1218 
  1219 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1220 INCOMPATIBILITY.
  1221 
  1222 * HOL/records: generalised field-update to take a function on the
  1223 field rather than the new value: r(|A := x|) is translated to A_update
  1224 (K x) r The K-combinator that is internally used is called K_record.
  1225 INCOMPATIBILITY: Usage of the plain update functions has to be
  1226 adapted.
  1227  
  1228 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1229 * x = 0, which are required for a semiring.  Richer structures do not
  1230 inherit from semiring_0 anymore, because this property is a theorem
  1231 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1232 there is more to prove, but this is mostly trivial.
  1233 
  1234 * Class "recpower" is generalized to arbitrary monoids, not just
  1235 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1236 commutativity or semiring properties additionally.
  1237 
  1238 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1239 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1240 better use 'abbreviation'.
  1241 
  1242 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1243 
  1244 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1245 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1246 significant changes for setting up numeral syntax for types:
  1247   - New constants Numeral.pred and Numeral.succ instead
  1248       of former Numeral.bin_pred and Numeral.bin_succ.
  1249   - Use integer operations instead of bin_add, bin_mult and so on.
  1250   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1251   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1252 
  1253 See src/HOL/Integ/IntArith.thy for an example setup.
  1254 
  1255 * Command 'normal_form' computes the normal form of a term that may
  1256 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1257 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1258 heavy-duty computations because the functions are compiled to ML
  1259 first.  Correspondingly, a method "normalization" is provided.  See
  1260 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1261 
  1262 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1263 25 like -->); output depends on the "iff" print_mode, the default is
  1264 "A = B" (with priority 50).
  1265 
  1266 * Relations less (<) and less_eq (<=) are also available on type bool.
  1267 Modified syntax to disallow nesting without explicit parentheses,
  1268 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1269 INCOMPATIBILITY.
  1270 
  1271 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1272 
  1273 * Relation composition operator "op O" now has precedence 75 and binds
  1274 stronger than union and intersection. INCOMPATIBILITY.
  1275 
  1276 * The old set interval syntax "{m..n(}" (and relatives) has been
  1277 removed.  Use "{m..<n}" (and relatives) instead.
  1278 
  1279 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1280 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1281 ``declare [[simproc del: neq]]''.
  1282 
  1283 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1284 True/False.
  1285 
  1286 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1287 
  1288 * Theorem setsum_mult renamed to setsum_right_distrib.
  1289 
  1290 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1291 ``rule'' method.
  1292 
  1293 * Reimplemented methods "sat" and "satx", with several improvements:
  1294 goals no longer need to be stated as "<prems> ==> False", equivalences
  1295 (i.e. "=" on type bool) are handled, variable names of the form
  1296 "lit_<n>" are no longer reserved, significant speedup.
  1297 
  1298 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1299 zChaff is still supported as well.
  1300 
  1301 * 'inductive' and 'datatype': provide projections of mutual rules,
  1302 bundled as foo_bar.inducts;
  1303 
  1304 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1305 Library.
  1306 
  1307 * Library: moved theory Accessible_Part to main HOL.
  1308 
  1309 * Library: added theory Coinductive_List of potentially infinite lists
  1310 as greatest fixed-point.
  1311 
  1312 * Library: added theory AssocList which implements (finite) maps as
  1313 association lists.
  1314 
  1315 * Method "evaluation" solves goals (i.e. a boolean expression)
  1316 efficiently by compiling it to ML.  The goal is "proved" (via an
  1317 oracle) if it evaluates to True.
  1318 
  1319 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1320 also when invoked by the simplifier.  This results in the Simplifier
  1321 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1322 Configuration option fast_arith_split_limit=0 recovers the old
  1323 behavior.
  1324 
  1325 * Support for hex (0x20) and binary (0b1001) numerals.
  1326 
  1327 * New method: reify eqs (t), where eqs are equations for an
  1328 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1329 parameter, computes a term s::'b and a list xs::'a list and proves the
  1330 theorem I xs s = t. This is also known as reification or quoting. The
  1331 resulting theorem is applied to the subgoal to substitute t with I xs
  1332 s.  If t is omitted, the subgoal itself is reified.
  1333 
  1334 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1335 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1336 where f is supposed to be a computable function (in the sense of code
  1337 generattion). The method uses reify to compute s and xs as above then
  1338 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1339 r and finally gets the theorem t = r, which is again applied to the
  1340 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1341 
  1342 * Reflection: Automatic reification now handels binding, an example is
  1343 available in src/HOL/ex/ReflectionEx.thy
  1344 
  1345 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1346 command 'statespace' that is similar to 'record', but introduces an
  1347 abstract specification based on the locale infrastructure instead of
  1348 HOL types.  This leads to extra flexibility in composing state spaces,
  1349 in particular multiple inheritance and renaming of components.
  1350 
  1351 
  1352 *** HOL-Complex ***
  1353 
  1354 * Hyperreal: Functions root and sqrt are now defined on negative real
  1355 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1356 Nonnegativity side conditions have been removed from many lemmas, so
  1357 that more subgoals may now be solved by simplification; potential
  1358 INCOMPATIBILITY.
  1359 
  1360 * Real: new type classes formalize real normed vector spaces and
  1361 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1362 and norm :: 'a => real.
  1363 
  1364 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1365 reals into other types. The overloaded constant Reals :: 'a set is now
  1366 defined as range of_real; potential INCOMPATIBILITY.
  1367 
  1368 * Real: proper support for ML code generation, including 'quickcheck'.
  1369 Reals are implemented as arbitrary precision rationals.
  1370 
  1371 * Hyperreal: Several constants that previously worked only for the
  1372 reals have been generalized, so they now work over arbitrary vector
  1373 spaces. Type annotations may need to be added in some cases; potential
  1374 INCOMPATIBILITY.
  1375 
  1376   Infinitesimal  :: ('a::real_normed_vector) star set
  1377   HFinite        :: ('a::real_normed_vector) star set
  1378   HInfinite      :: ('a::real_normed_vector) star set
  1379   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1380   monad          :: ('a::real_normed_vector) star => 'a star set
  1381   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1382   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1383   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1384   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1385   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1386   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1387   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1388   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1389   sgn            :: 'a::real_normed_vector => 'a
  1390   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1391 
  1392 * Complex: Some complex-specific constants are now abbreviations for
  1393 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1394 hnorm.  Other constants have been entirely removed in favor of the
  1395 polymorphic versions (INCOMPATIBILITY):
  1396 
  1397   approx        <-- capprox
  1398   HFinite       <-- CFinite
  1399   HInfinite     <-- CInfinite
  1400   Infinitesimal <-- CInfinitesimal
  1401   monad         <-- cmonad
  1402   galaxy        <-- cgalaxy
  1403   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1404   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1405   (ns)deriv     <-- (ns)cderiv
  1406 
  1407 
  1408 *** HOL-Algebra ***
  1409 
  1410 * Formalisation of ideals and the quotient construction over rings.
  1411 
  1412 * Order and lattice theory no longer based on records.
  1413 INCOMPATIBILITY.
  1414 
  1415 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1416 greatest_closed.  INCOMPATIBILITY.
  1417 
  1418 * Method algebra is now set up via an attribute.  For examples see
  1419 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1420 of algebraic structures.
  1421 
  1422 * Renamed theory CRing to Ring.
  1423 
  1424 
  1425 *** HOL-Nominal ***
  1426 
  1427 * Substantial, yet incomplete support for nominal datatypes (binding
  1428 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  1429 src/HOL/Nominal/Examples.  Prospective users should consult
  1430 http://isabelle.in.tum.de/nominal/
  1431 
  1432 
  1433 *** ML ***
  1434 
  1435 * ML basics: just one true type int, which coincides with IntInf.int
  1436 (even on SML/NJ).
  1437 
  1438 * ML within Isar: antiquotations allow to embed statically-checked
  1439 formal entities in the source, referring to the context available at
  1440 compile-time.  For example:
  1441 
  1442 ML {* @{sort "{zero,one}"} *}
  1443 ML {* @{typ "'a => 'b"} *}
  1444 ML {* @{term "%x. x"} *}
  1445 ML {* @{prop "x == y"} *}
  1446 ML {* @{ctyp "'a => 'b"} *}
  1447 ML {* @{cterm "%x. x"} *}
  1448 ML {* @{cprop "x == y"} *}
  1449 ML {* @{thm asm_rl} *}
  1450 ML {* @{thms asm_rl} *}
  1451 ML {* @{type_name c} *}
  1452 ML {* @{type_syntax c} *}
  1453 ML {* @{const_name c} *}
  1454 ML {* @{const_syntax c} *}
  1455 ML {* @{context} *}
  1456 ML {* @{theory} *}
  1457 ML {* @{theory Pure} *}
  1458 ML {* @{theory_ref} *}
  1459 ML {* @{theory_ref Pure} *}
  1460 ML {* @{simpset} *}
  1461 ML {* @{claset} *}
  1462 ML {* @{clasimpset} *}
  1463 
  1464 The same works for sources being ``used'' within an Isar context.
  1465 
  1466 * ML in Isar: improved error reporting; extra verbosity with
  1467 ML_Context.trace enabled.
  1468 
  1469 * Pure/General/table.ML: the join operations now works via exceptions
  1470 DUP/SAME instead of type option. This is simpler in simple cases, and
  1471 admits slightly more efficient complex applications.
  1472 
  1473 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1474 use Context.generic instead of just theory.
  1475 
  1476 * Pure: datatype Context.generic joins theory/Proof.context and
  1477 provides some facilities for code that works in either kind of
  1478 context, notably GenericDataFun for uniform theory and proof data.
  1479 
  1480 * Pure: simplified internal attribute type, which is now always
  1481 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  1482 local (Proof.context) attributes have been discontinued, while
  1483 minimizing code duplication. Thm.rule_attribute and
  1484 Thm.declaration_attribute build canonical attributes; see also structure
  1485 Context for further operations on Context.generic, notably
  1486 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  1487 declarations and definitions.
  1488 
  1489 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1490 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1491 init only required for impure data. INCOMPATIBILITY: empty really need
  1492 to be empty (no dependencies on theory content!)
  1493 
  1494 * Pure/kernel: consts certification ignores sort constraints given in
  1495 signature declarations. (This information is not relevant to the
  1496 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  1497 potential INCOMPATIBILITY.
  1498 
  1499 * Pure: axiomatic type classes are now purely definitional, with
  1500 explicit proofs of class axioms and super class relations performed
  1501 internally. See Pure/axclass.ML for the main internal interfaces --
  1502 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1503 AxClass.axiomatize_class/classrel/arity supersede
  1504 Sign.add_classes/classrel/arities.
  1505 
  1506 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1507 global/local versions on theory vs. Proof.context have been
  1508 discontinued; Attrib.syntax and Method.syntax have been adapted
  1509 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1510 attributes, methods, etc.
  1511 
  1512 * Pure: several functions of signature "... -> theory -> theory * ..."
  1513 have been reoriented to "... -> theory -> ... * theory" in order to
  1514 allow natural usage in combination with the ||>, ||>>, |-> and
  1515 fold_map combinators.
  1516 
  1517 * Pure: official theorem names (closed derivations) and additional
  1518 comments (tags) are now strictly separate.  Name hints -- which are
  1519 maintained as tags -- may be attached any time without affecting the
  1520 derivation.
  1521 
  1522 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1523 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1524 achieve the old behaviour.
  1525 
  1526 * Pure: the "Goal" constant is now called "prop", supporting a
  1527 slightly more general idea of ``protecting'' meta-level rule
  1528 statements.
  1529 
  1530 * Pure: Logic.(un)varify only works in a global context, which is now
  1531 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1532 Logic.legacy_(un)varify as temporary workaround.
  1533 
  1534 * Pure: structure Name provides scalable operations for generating
  1535 internal variable names, notably Name.variants etc.  This replaces
  1536 some popular functions from term.ML:
  1537 
  1538   Term.variant		->  Name.variant
  1539   Term.variantlist	->  Name.variant_list
  1540   Term.invent_names	->  Name.invent_list
  1541 
  1542 Note that low-level renaming rarely occurs in new code -- operations
  1543 from structure Variable are used instead (see below).
  1544 
  1545 * Pure: structure Variable provides fundamental operations for proper
  1546 treatment of fixed/schematic variables in a context.  For example,
  1547 Variable.import introduces fixes for schematics of given facts and
  1548 Variable.export reverses the effect (up to renaming) -- this replaces
  1549 various freeze_thaw operations.
  1550 
  1551 * Pure: structure Goal provides simple interfaces for
  1552 init/conclude/finish and tactical prove operations (replacing former
  1553 Tactic.prove).  Goal.prove is the canonical way to prove results
  1554 within a given context; Goal.prove_global is a degraded version for
  1555 theory level goals, including a global Drule.standard.  Note that
  1556 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1557 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1558 in a locale context).
  1559 
  1560 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  1561 and type checking (Syntax.check_term etc.), with common combinations
  1562 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  1563 which are considered legacy and await removal.
  1564 
  1565 * Pure/Syntax: generic interfaces for type unchecking
  1566 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  1567 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  1568 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  1569 available for convenience, but refer to the very same operations using
  1570 a mere theory instead of a full context.
  1571 
  1572 * Isar: simplified treatment of user-level errors, using exception
  1573 ERROR of string uniformly.  Function error now merely raises ERROR,
  1574 without any side effect on output channels.  The Isar toplevel takes
  1575 care of proper display of ERROR exceptions.  ML code may use plain
  1576 handle/can/try; cat_error may be used to concatenate errors like this:
  1577 
  1578   ... handle ERROR msg => cat_error msg "..."
  1579 
  1580 Toplevel ML code (run directly or through the Isar toplevel) may be
  1581 embedded into the Isar toplevel with exception display/debug like
  1582 this:
  1583 
  1584   Isar.toplevel (fn () => ...)
  1585 
  1586 INCOMPATIBILITY, removed special transform_error facilities, removed
  1587 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1588 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1589 -- use plain ERROR instead.
  1590 
  1591 * Isar: theory setup now has type (theory -> theory), instead of a
  1592 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1593 
  1594 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  1595 ProofContext.debug/verbose flags.
  1596 
  1597 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1598 theory before entering a proof state.  Transactions now always see a
  1599 quasi-functional intermediate checkpoint, both in interactive and
  1600 batch mode.
  1601 
  1602 * Isar: simplified interfaces for outer syntax.  Renamed
  1603 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  1604 OuterSyntax.add_parsers -- this functionality is now included in
  1605 OuterSyntax.command etc.  INCOMPATIBILITY.
  1606 
  1607 * Simplifier: the simpset of a running simplification process now
  1608 contains a proof context (cf. Simplifier.the_context), which is the
  1609 very context that the initial simpset has been retrieved from (by
  1610 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1611 (solver, looper etc.) may depend on arbitrary proof data.
  1612 
  1613 * Simplifier.inherit_context inherits the proof context (plus the
  1614 local bounds) of the current simplification process; any simproc
  1615 etc. that calls the Simplifier recursively should do this!  Removed
  1616 former Simplifier.inherit_bounds, which is already included here --
  1617 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1618 specify an explicit context using Simplifier.context/theory_context.
  1619 
  1620 * Simplifier/Classical Reasoner: more abstract interfaces
  1621 change_simpset/claset for modifying the simpset/claset reference of a
  1622 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1623 INCOMPATIBILITY.
  1624 
  1625 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1626 "Trueprop" etc.
  1627 
  1628 
  1629 *** System ***
  1630 
  1631 * settings: the default heap location within ISABELLE_HOME_USER now
  1632 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  1633 Isabelle installations.
  1634 
  1635 * isabelle-process: option -S (secure mode) disables some critical
  1636 operations, notably runtime compilation and evaluation of ML source
  1637 code.
  1638 
  1639 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  1640 
  1641 * Support for parallel execution, using native multicore support of
  1642 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  1643 independent theories, according to the given theory header
  1644 specifications. The maximum number of worker threads is specified via
  1645 usedir option -M or the "max-threads" setting in Proof General. A
  1646 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  1647 to 6 on a 8-core machine.  User-code needs to observe certain
  1648 guidelines for thread-safe programming, see appendix A in the Isar
  1649 Implementation manual.
  1650 
  1651 
  1652 
  1653 New in Isabelle2005 (October 2005)
  1654 ----------------------------------
  1655 
  1656 *** General ***
  1657 
  1658 * Theory headers: the new header syntax for Isar theories is
  1659 
  1660   theory <name>
  1661   imports <theory1> ... <theoryN>
  1662   uses <file1> ... <fileM>
  1663   begin
  1664 
  1665 where the 'uses' part is optional.  The previous syntax
  1666 
  1667   theory <name> = <theory1> + ... + <theoryN>:
  1668 
  1669 will disappear in the next release.  Use isatool fixheaders to convert
  1670 existing theory files.  Note that there is no change in ancient
  1671 non-Isar theories now, but these will disappear soon.
  1672 
  1673 * Theory loader: parent theories can now also be referred to via
  1674 relative and absolute paths.
  1675 
  1676 * Command 'find_theorems' searches for a list of criteria instead of a
  1677 list of constants. Known criteria are: intro, elim, dest, name:string,
  1678 simp:term, and any term. Criteria can be preceded by '-' to select
  1679 theorems that do not match. Intro, elim, dest select theorems that
  1680 match the current goal, name:s selects theorems whose fully qualified
  1681 name contain s, and simp:term selects all simplification rules whose
  1682 lhs match term.  Any other term is interpreted as pattern and selects
  1683 all theorems matching the pattern. Available in ProofGeneral under
  1684 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1685 
  1686   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1687 
  1688 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1689 matching the current goal as introduction rule and not having "HOL."
  1690 in their name (i.e. not being defined in theory HOL).
  1691 
  1692 * Command 'thms_containing' has been discontinued in favour of
  1693 'find_theorems'; INCOMPATIBILITY.
  1694 
  1695 * Communication with Proof General is now 8bit clean, which means that
  1696 Unicode text in UTF-8 encoding may be used within theory texts (both
  1697 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1698 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1699 
  1700   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1701   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1702 
  1703 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1704 Classical Reasoner.  Typical big applications run around 2 times
  1705 faster.
  1706 
  1707 
  1708 *** Document preparation ***
  1709 
  1710 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1711 of raw sources.  Only those symbols that do not require additional
  1712 LaTeX packages (depending on comments in isabellesym.sty) are
  1713 displayed properly, everything else is left verbatim.  isatool display
  1714 and isatool print are used as front ends (these are subject to the
  1715 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1716 
  1717 * Command tags control specific markup of certain regions of text,
  1718 notably folding and hiding.  Predefined tags include "theory" (for
  1719 theory begin and end), "proof" for proof commands, and "ML" for
  1720 commands involving ML code; the additional tags "visible" and
  1721 "invisible" are unused by default.  Users may give explicit tag
  1722 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1723 interpretation of tags is determined by the LaTeX job during document
  1724 preparation: see option -V of isatool usedir, or options -n and -t of
  1725 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1726 \isadroptag.
  1727 
  1728 Several document versions may be produced at the same time via isatool
  1729 usedir (the generated index.html will link all of them).  Typical
  1730 specifications include ''-V document=theory,proof,ML'' to present
  1731 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1732 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1733 these parts without any formal replacement text.  The Isabelle site
  1734 default settings produce ''document'' and ''outline'' versions as
  1735 specified above.
  1736 
  1737 * Several new antiquotations:
  1738 
  1739   @{term_type term} prints a term with its type annotated;
  1740 
  1741   @{typeof term} prints the type of a term;
  1742 
  1743   @{const const} is the same as @{term const}, but checks that the
  1744   argument is a known logical constant;
  1745 
  1746   @{term_style style term} and @{thm_style style thm} print a term or
  1747   theorem applying a "style" to it
  1748 
  1749   @{ML text}
  1750 
  1751 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1752 definitions, equations, inequations etc., 'concl' printing only the
  1753 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1754 to print the specified premise.  TermStyle.add_style provides an ML
  1755 interface for introducing further styles.  See also the "LaTeX Sugar"
  1756 document practical applications.  The ML antiquotation prints
  1757 type-checked ML expressions verbatim.
  1758 
  1759 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1760 and 'text' support optional locale specification '(in loc)', which
  1761 specifies the default context for interpreting antiquotations.  For
  1762 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1763 
  1764 * Option 'locale=NAME' of antiquotations specifies an alternative
  1765 context interpreting the subsequent argument.  For example: @{thm
  1766 [locale=lattice] inf_assoc}.
  1767 
  1768 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1769 a proof context.
  1770 
  1771 * Proper output of antiquotations for theory commands involving a
  1772 proof context (such as 'locale' or 'theorem (in loc) ...').
  1773 
  1774 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1775 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1776 
  1777 * isatool usedir: new option -C (default true) controls whether option
  1778 -D should include a copy of the original document directory; -C false
  1779 prevents unwanted effects such as copying of administrative CVS data.
  1780 
  1781 
  1782 *** Pure ***
  1783 
  1784 * Considerably improved version of 'constdefs' command.  Now performs
  1785 automatic type-inference of declared constants; additional support for
  1786 local structure declarations (cf. locales and HOL records), see also
  1787 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1788 sequential dependencies of definitions within a single 'constdefs'
  1789 section; moreover, the declared name needs to be an identifier.  If
  1790 all fails, consider to fall back on 'consts' and 'defs' separately.
  1791 
  1792 * Improved indexed syntax and implicit structures.  First of all,
  1793 indexed syntax provides a notational device for subscripted
  1794 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1795 expressions.  Secondly, in a local context with structure
  1796 declarations, number indexes \<^sub>n or the empty index (default
  1797 number 1) refer to a certain fixed variable implicitly; option
  1798 show_structs controls printing of implicit structures.  Typical
  1799 applications of these concepts involve record types and locales.
  1800 
  1801 * New command 'no_syntax' removes grammar declarations (and
  1802 translations) resulting from the given syntax specification, which is
  1803 interpreted in the same manner as for the 'syntax' command.
  1804 
  1805 * 'Advanced' translation functions (parse_translation etc.) may depend
  1806 on the signature of the theory context being presently used for
  1807 parsing/printing, see also isar-ref manual.
  1808 
  1809 * Improved 'oracle' command provides a type-safe interface to turn an
  1810 ML expression of type theory -> T -> term into a primitive rule of
  1811 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1812 is already included here); see also FOL/ex/IffExample.thy;
  1813 INCOMPATIBILITY.
  1814 
  1815 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1816 before); "cI" is no longer bound, use "c.intro" instead.
  1817 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1818 axclasses vs. locales.
  1819 
  1820 * Improved internal renaming of symbolic identifiers -- attach primes
  1821 instead of base 26 numbers.
  1822 
  1823 * New flag show_question_marks controls printing of leading question
  1824 marks in schematic variable names.
  1825 
  1826 * In schematic variable names, *any* symbol following \<^isub> or
  1827 \<^isup> is now treated as part of the base name.  For example, the
  1828 following works without printing of awkward ".0" indexes:
  1829 
  1830   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1831     by simp
  1832 
  1833 * Inner syntax includes (*(*nested*) comments*).
  1834 
  1835 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1836 annotations as "(00...)".
  1837 
  1838 * Clear separation of logical types and nonterminals, where the latter
  1839 may only occur in 'syntax' specifications or type abbreviations.
  1840 Before that distinction was only partially implemented via type class
  1841 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1842 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1843 exotic syntax specifications may require further adaption
  1844 (e.g. Cube/Cube.thy).
  1845 
  1846 * Removed obsolete type class "logic", use the top sort {} instead.
  1847 Note that non-logical types should be declared as 'nonterminals'
  1848 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1849 specifications.
  1850 
  1851 * Attributes 'induct' and 'cases': type or set names may now be
  1852 locally fixed variables as well.
  1853 
  1854 * Simplifier: can now control the depth to which conditional rewriting
  1855 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1856 Limit.
  1857 
  1858 * Simplifier: simplification procedures may now take the current
  1859 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1860 interface), which is very useful for calling the Simplifier
  1861 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1862 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1863 low-level mk_simproc no longer applies Logic.varify internally, to
  1864 allow for use in a context of fixed variables.
  1865 
  1866 * thin_tac now works even if the assumption being deleted contains !!
  1867 or ==>.  More generally, erule now works even if the major premise of
  1868 the elimination rule contains !! or ==>.
  1869 
  1870 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1871 
  1872 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1873 from Pure, which contains all common declarations already.  Both
  1874 theories are defined via plain Isabelle/Isar .thy files.
  1875 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1876 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1877 use isatool fixcpure to adapt your theory and ML sources.
  1878 
  1879 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1880 selections of theorems in named facts via index ranges.
  1881 
  1882 * 'print_theorems': in theory mode, really print the difference
  1883 wrt. the last state (works for interactive theory development only),
  1884 in proof mode print all local facts (cf. 'print_facts');
  1885 
  1886 * 'hide': option '(open)' hides only base names.
  1887 
  1888 * More efficient treatment of intermediate checkpoints in interactive
  1889 theory development.
  1890 
  1891 * Code generator is now invoked via code_module (incremental code
  1892 generation) and code_library (modular code generation, ML structures
  1893 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1894 must be quoted when used as identifiers.
  1895 
  1896 * New 'value' command for reading, evaluating and printing terms using
  1897 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1898 quoted when used as identifier.
  1899 
  1900 
  1901 *** Locales ***
  1902 
  1903 * New commands for the interpretation of locale expressions in
  1904 theories (1), locales (2) and proof contexts (3).  These generate
  1905 proof obligations from the expression specification.  After the
  1906 obligations have been discharged, theorems of the expression are added
  1907 to the theory, target locale or proof context.  The synopsis of the
  1908 commands is a follows:
  1909 
  1910   (1) interpretation expr inst
  1911   (2) interpretation target < expr
  1912   (3) interpret expr inst
  1913 
  1914 Interpretation in theories and proof contexts require a parameter
  1915 instantiation of terms from the current context.  This is applied to
  1916 specifications and theorems of the interpreted expression.
  1917 Interpretation in locales only permits parameter renaming through the
  1918 locale expression.  Interpretation is smart in that interpretations
  1919 that are active already do not occur in proof obligations, neither are
  1920 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1921 inspect active interpretations of a particular locale.  For details,
  1922 see the Isar Reference manual.  Examples can be found in
  1923 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1924 
  1925 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1926 'interpret' instead.
  1927 
  1928 * New context element 'constrains' for adding type constraints to
  1929 parameters.
  1930 
  1931 * Context expressions: renaming of parameters with syntax
  1932 redeclaration.
  1933 
  1934 * Locale declaration: 'includes' disallowed.
  1935 
  1936 * Proper static binding of attribute syntax -- i.e. types / terms /
  1937 facts mentioned as arguments are always those of the locale definition
  1938 context, independently of the context of later invocations.  Moreover,
  1939 locale operations (renaming and type / term instantiation) are applied
  1940 to attribute arguments as expected.
  1941 
  1942 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1943 actual attributes; rare situations may require Attrib.attribute to
  1944 embed those attributes into Attrib.src that lack concrete syntax.
  1945 Attribute implementations need to cooperate properly with the static
  1946 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1947 Attrib.XXX_thm etc. already do the right thing without further
  1948 intervention.  Only unusual applications -- such as "where" or "of"
  1949 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1950 on the context and the facts involved -- may have to assign parsed
  1951 values to argument tokens explicitly.
  1952 
  1953 * Changed parameter management in theorem generation for long goal
  1954 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1955 theorem statement in rare situations.
  1956 
  1957 * Locale inspection command 'print_locale' omits notes elements.  Use
  1958 'print_locale!' to have them included in the output.
  1959 
  1960 
  1961 *** Provers ***
  1962 
  1963 * Provers/hypsubst.ML: improved version of the subst method, for
  1964 single-step rewriting: it now works in bound variable contexts. New is
  1965 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1966 rewrite a different subterm than the original subst method, which is
  1967 still available as 'simplesubst'.
  1968 
  1969 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1970 and quasi orders.
  1971 
  1972 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1973 reflexive-transitive closure of relations.
  1974 
  1975 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1976 limit (previously hard-coded with a value of 20) user-definable.
  1977 
  1978 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1979 is peformed already.  Object-logics merely need to finish their
  1980 initial simpset configuration as before.  INCOMPATIBILITY.
  1981 
  1982 
  1983 *** HOL ***
  1984 
  1985 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1986 
  1987   syntax (epsilon)
  1988     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1989 
  1990 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1991 and x-symbol; use option '-m epsilon' to get it actually printed.
  1992 Moreover, the mathematically important symbolic identifier \<epsilon>
  1993 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1994 
  1995 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1996 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1997 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1998 support corresponding Isar calculations.
  1999 
  2000 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2001 instead of ":".
  2002 
  2003 * theory SetInterval: changed the syntax for open intervals:
  2004 
  2005   Old       New
  2006   {..n(}    {..<n}
  2007   {)n..}    {n<..}
  2008   {m..n(}   {m..<n}
  2009   {)m..n}   {m<..n}
  2010   {)m..n(}  {m<..<n}
  2011 
  2012 The old syntax is still supported but will disappear in the next
  2013 release.  For conversion use the following Emacs search and replace
  2014 patterns (these are not perfect but work quite well):
  2015 
  2016   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2017   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2018 
  2019 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2020 equalities in commutative rings; method 'algebra' provides a generic
  2021 interface.
  2022 
  2023 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2024 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2025 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2026 be a tuple pattern.
  2027 
  2028 Some new syntax forms are available:
  2029 
  2030   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2031   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2032   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2033   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2034 
  2035 The latter form "\<Sum>x < k. e" used to be based on a separate
  2036 function "Summation", which has been discontinued.
  2037 
  2038 * theory Finite_Set: in structured induction proofs, the insert case
  2039 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2040 (insert F x)'.
  2041 
  2042 * The 'refute' command has been extended to support a much larger
  2043 fragment of HOL, including axiomatic type classes, constdefs and
  2044 typedefs, inductive datatypes and recursion.
  2045 
  2046 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2047 Requires zChaff with proof generation to be installed.  See
  2048 HOL/ex/SAT_Examples.thy for examples.
  2049 
  2050 * Datatype induction via method 'induct' now preserves the name of the
  2051 induction variable. For example, when proving P(xs::'a list) by
  2052 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2053 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2054 in unstructured proof scripts.
  2055 
  2056 * Reworked implementation of records.  Improved scalability for
  2057 records with many fields, avoiding performance problems for type
  2058 inference. Records are no longer composed of nested field types, but
  2059 of nested extension types. Therefore the record type only grows linear
  2060 in the number of extensions and not in the number of fields.  The
  2061 top-level (users) view on records is preserved.  Potential
  2062 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2063 old record representation. The type generated for a record is called
  2064 <record_name>_ext_type.
  2065 
  2066 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2067 proofs triggered by a record definition or a simproc (if
  2068 quick_and_dirty is enabled).  Definitions of large records can take
  2069 quite long.
  2070 
  2071 New simproc record_upd_simproc for simplification of multiple record
  2072 updates enabled by default.  Moreover, trivial updates are also
  2073 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2074 occasionally, since simplification is more powerful by default.
  2075 
  2076 * typedef: proper support for polymorphic sets, which contain extra
  2077 type-variables in the term.
  2078 
  2079 * Simplifier: automatically reasons about transitivity chains
  2080 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2081 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2082 old proofs break occasionally as simplification may now solve more
  2083 goals than previously.
  2084 
  2085 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2086 present.  Works for all partial orders (class "order"), in particular
  2087 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2088 just like y <= x.
  2089 
  2090 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2091 bound variable or a constant then the let is unfolded.  Otherwise
  2092 first a is simplified to b, and then f b is simplified to g. If
  2093 possible we abstract b from g arriving at "let x = b in h x",
  2094 otherwise we unfold the let and arrive at g.  The simproc can be
  2095 enabled/disabled by the reference use_let_simproc.  Potential
  2096 INCOMPATIBILITY since simplification is more powerful by default.
  2097 
  2098 * Classical reasoning: the meson method now accepts theorems as arguments.
  2099 
  2100 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2101 jobs to provide advice on the provability of subgoals.
  2102 
  2103 * Theory OrderedGroup and Ring_and_Field: various additions and
  2104 improvements to faciliate calculations involving equalities and
  2105 inequalities.
  2106 
  2107 The following theorems have been eliminated or modified
  2108 (INCOMPATIBILITY):
  2109 
  2110   abs_eq             now named abs_of_nonneg
  2111   abs_of_ge_0        now named abs_of_nonneg
  2112   abs_minus_eq       now named abs_of_nonpos
  2113   imp_abs_id         now named abs_of_nonneg
  2114   imp_abs_neg_id     now named abs_of_nonpos
  2115   mult_pos           now named mult_pos_pos
  2116   mult_pos_le        now named mult_nonneg_nonneg
  2117   mult_pos_neg_le    now named mult_nonneg_nonpos
  2118   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2119   mult_neg           now named mult_neg_neg
  2120   mult_neg_le        now named mult_nonpos_nonpos
  2121 
  2122 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2123      
  2124      zero_le_square
  2125      not_square_less_zero 
  2126 
  2127   The following lemmas have been deleted from Real/RealPow:
  2128   
  2129      realpow_zero_zero
  2130      realpow_two
  2131      realpow_less
  2132      zero_le_power
  2133      realpow_two_le
  2134      abs_realpow_two
  2135      realpow_two_abs     
  2136 
  2137 * Theory Parity: added rules for simplifying exponents.
  2138 
  2139 * Theory List:
  2140 
  2141 The following theorems have been eliminated or modified
  2142 (INCOMPATIBILITY):
  2143 
  2144   list_all_Nil       now named list_all.simps(1)
  2145   list_all_Cons      now named list_all.simps(2)
  2146   list_all_conv      now named list_all_iff
  2147   set_mem_eq         now named mem_iff
  2148 
  2149 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2150 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2151 
  2152 
  2153 *** HOL-Complex ***
  2154 
  2155 * Theory RealDef: better support for embedding natural numbers and
  2156 integers in the reals.
  2157 
  2158 The following theorems have been eliminated or modified
  2159 (INCOMPATIBILITY):
  2160 
  2161   exp_ge_add_one_self  now requires no hypotheses
  2162   real_of_int_add      reversed direction of equality (use [symmetric])
  2163   real_of_int_minus    reversed direction of equality (use [symmetric])
  2164   real_of_int_diff     reversed direction of equality (use [symmetric])
  2165   real_of_int_mult     reversed direction of equality (use [symmetric])
  2166 
  2167 * Theory RComplete: expanded support for floor and ceiling functions.
  2168 
  2169 * Theory Ln is new, with properties of the natural logarithm
  2170 
  2171 * Hyperreal: There is a new type constructor "star" for making
  2172 nonstandard types.  The old type names are now type synonyms:
  2173 
  2174   hypreal = real star
  2175   hypnat = nat star
  2176   hcomplex = complex star
  2177 
  2178 * Hyperreal: Many groups of similarly-defined constants have been
  2179 replaced by polymorphic versions (INCOMPATIBILITY):
  2180 
  2181   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2182 
  2183   starset      <-- starsetNat, starsetC
  2184   *s*          <-- *sNat*, *sc*
  2185   starset_n    <-- starsetNat_n, starsetC_n
  2186   *sn*         <-- *sNatn*, *scn*
  2187   InternalSets <-- InternalNatSets, InternalCSets
  2188 
  2189   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2190   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2191   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2192   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2193   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2194 
  2195 * Hyperreal: Many type-specific theorems have been removed in favor of
  2196 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2197 
  2198   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2199   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2200   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2201   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2202   right_minus <-- hypreal_add_minus
  2203   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2204   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2205   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2206   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2207   mult_1_right <-- hcomplex_mult_one_right
  2208   mult_zero_left <-- hcomplex_mult_zero_left
  2209   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2210   right_distrib <-- hypnat_add_mult_distrib2
  2211   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2212   right_inverse <-- hypreal_mult_inverse
  2213   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2214   order_refl <-- {hypreal,hypnat}_le_refl
  2215   order_trans <-- {hypreal,hypnat}_le_trans
  2216   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2217   order_less_le <-- {hypreal,hypnat}_less_le
  2218   linorder_linear <-- {hypreal,hypnat}_le_linear
  2219   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2220   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2221   add_nonneg_nonneg <-- hypreal_le_add_order
  2222 
  2223 * Hyperreal: Separate theorems having to do with type-specific
  2224 versions of constants have been merged into theorems that apply to the
  2225 new polymorphic constants (INCOMPATIBILITY):
  2226 
  2227   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2228   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2229   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2230   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2231   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2232   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2233   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2234   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2235   STAR_diff <-- {STAR,STARC}_diff
  2236   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2237     STARC_hcomplex_of_complex}_image_subset
  2238   starset_n_Un <-- starset{Nat,C}_n_Un
  2239   starset_n_Int <-- starset{Nat,C}_n_Int
  2240   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2241   starset_n_diff <-- starset{Nat,C}_n_diff
  2242   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2243   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2244   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2245   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2246   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2247   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2248   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2249   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2250   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2251   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2252   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2253   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2254   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2255   starfun_diff <-- starfun{C,RC,CR}_diff
  2256   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2257   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2258   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2259   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2260   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2261   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2262   starfun_Id <-- starfunC_Id
  2263   starfun_approx <-- starfun{Nat,CR}_approx
  2264   starfun_capprox <-- starfun{C,RC}_capprox
  2265   starfun_abs <-- starfunNat_rabs
  2266   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2267   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2268   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2269   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2270   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2271   starfun_add_approx <-- starfunCR_add_approx
  2272   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2273   starfun_divide <-- starfun{C,CR,RC}_divide
  2274   starfun_n <-- starfun{Nat,C}_n
  2275   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2276   starfun_n_add <-- starfun{Nat,C}_n_add
  2277   starfun_n_add_minus <-- starfunNat_n_add_minus
  2278   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2279   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2280   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2281 
  2282   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2283   star_n_minus <-- {hypreal,hcomplex}_minus
  2284   star_n_diff <-- {hypreal,hcomplex}_diff
  2285   star_n_mult <-- {hypreal,hcomplex}_mult
  2286   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2287   star_n_le <-- {hypreal,hypnat}_le
  2288   star_n_less <-- {hypreal,hypnat}_less
  2289   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2290   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2291   star_n_abs <-- hypreal_hrabs
  2292   star_n_divide <-- hcomplex_divide
  2293 
  2294   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2295   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2296   star_of_diff <-- hypreal_of_real_diff
  2297   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2298   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2299   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2300   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2301   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2302   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2303   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2304   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2305   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2306   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2307   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2308   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2309   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2310   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2311   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2312   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2313   star_of_power <-- hypreal_of_real_power
  2314   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2315 
  2316 * Hyperreal: new method "transfer" that implements the transfer
  2317 principle of nonstandard analysis. With a subgoal that mentions
  2318 nonstandard types like "'a star", the command "apply transfer"
  2319 replaces it with an equivalent one that mentions only standard types.
  2320 To be successful, all free variables must have standard types; non-
  2321 standard variables must have explicit universal quantifiers.
  2322 
  2323 * Hyperreal: A theory of Taylor series.
  2324 
  2325 
  2326 *** HOLCF ***
  2327 
  2328 * Discontinued special version of 'constdefs' (which used to support
  2329 continuous functions) in favor of the general Pure one with full
  2330 type-inference.
  2331 
  2332 * New simplification procedure for solving continuity conditions; it
  2333 is much faster on terms with many nested lambda abstractions (cubic
  2334 instead of exponential time).
  2335 
  2336 * New syntax for domain package: selector names are now optional.
  2337 Parentheses should be omitted unless argument is lazy, for example:
  2338 
  2339   domain 'a stream = cons "'a" (lazy "'a stream")
  2340 
  2341 * New command 'fixrec' for defining recursive functions with pattern
  2342 matching; defining multiple functions with mutual recursion is also
  2343 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2344 sinr, or any data constructor defined by the domain package. The given
  2345 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2346 syntax and examples.
  2347 
  2348 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2349 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2350 but the proof obligation additionally includes an admissibility
  2351 requirement. The packages generate instances of class cpo or pcpo,
  2352 with continuity and strictness theorems for Rep and Abs.
  2353 
  2354 * HOLCF: Many theorems have been renamed according to a more standard naming
  2355 scheme (INCOMPATIBILITY):
  2356 
  2357   foo_inject:  "foo$x = foo$y ==> x = y"
  2358   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2359   foo_less:    "(foo$x << foo$y) = (x << y)"
  2360   foo_strict:  "foo$UU = UU"
  2361   foo_defined: "... ==> foo$x ~= UU"
  2362   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2363 
  2364 
  2365 *** ZF ***
  2366 
  2367 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2368 including the First Isomorphism Theorem (on quotienting by the kernel
  2369 of a homomorphism).
  2370 
  2371 * ZF/Simplifier: install second copy of type solver that actually
  2372 makes use of TC rules declared to Isar proof contexts (or locales);
  2373 the old version is still required for ML proof scripts.
  2374 
  2375 
  2376 *** Cube ***
  2377 
  2378 * Converted to Isar theory format; use locales instead of axiomatic
  2379 theories.
  2380 
  2381 
  2382 *** ML ***
  2383 
  2384 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2385 for ||>, ||>>, |>>,
  2386 
  2387 * Pure/library.ML no longer defines its own option datatype, but uses
  2388 that of the SML basis, which has constructors NONE and SOME instead of
  2389 None and Some, as well as exception Option.Option instead of OPTION.
  2390 The functions the, if_none, is_some, is_none have been adapted
  2391 accordingly, while Option.map replaces apsome.
  2392 
  2393 * Pure/library.ML: the exception LIST has been given up in favour of
  2394 the standard exceptions Empty and Subscript, as well as
  2395 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2396 superceded by the standard hd and tl functions etc.
  2397 
  2398 A number of basic list functions are no longer exported to the ML
  2399 toplevel, as they are variants of predefined functions.  The following
  2400 suggests how one can translate existing code:
  2401 
  2402     rev_append xs ys = List.revAppend (xs, ys)
  2403     nth_elem (i, xs) = List.nth (xs, i)
  2404     last_elem xs = List.last xs
  2405     flat xss = List.concat xss
  2406     seq fs = List.app fs
  2407     partition P xs = List.partition P xs
  2408     mapfilter f xs = List.mapPartial f xs
  2409 
  2410 * Pure/library.ML: several combinators for linear functional
  2411 transformations, notably reverse application and composition:
  2412 
  2413   x |> f                f #> g
  2414   (x, y) |-> f          f #-> g
  2415 
  2416 * Pure/library.ML: introduced/changed precedence of infix operators:
  2417 
  2418   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2419   infix 2 ?;
  2420   infix 3 o oo ooo oooo;
  2421   infix 4 ~~ upto downto;
  2422 
  2423 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2424 infix operators.
  2425 
  2426 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2427 fold_map support linear functional transformations and nesting.  For
  2428 example:
  2429 
  2430   fold f [x1, ..., xN] y =
  2431     y |> f x1 |> ... |> f xN
  2432 
  2433   (fold o fold) f [xs1, ..., xsN] y =
  2434     y |> fold f xs1 |> ... |> fold f xsN
  2435 
  2436   fold f [x1, ..., xN] =
  2437     f x1 #> ... #> f xN
  2438 
  2439   (fold o fold) f [xs1, ..., xsN] =
  2440     fold f xs1 #> ... #> fold f xsN
  2441 
  2442 * Pure/library.ML: the following selectors on type 'a option are
  2443 available:
  2444 
  2445   the:               'a option -> 'a  (*partial*)
  2446   these:             'a option -> 'a  where 'a = 'b list
  2447   the_default: 'a -> 'a option -> 'a
  2448   the_list:          'a option -> 'a list
  2449 
  2450 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2451 basic operations for association lists, following natural argument
  2452 order; moreover the explicit equality predicate passed here avoids
  2453 potentially expensive polymorphic runtime equality checks.
  2454 The old functions may be expressed as follows:
  2455 
  2456   assoc = uncurry (AList.lookup (op =))
  2457   assocs = these oo AList.lookup (op =)
  2458   overwrite = uncurry (AList.update (op =)) o swap
  2459 
  2460 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2461 
  2462   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2463   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2464 
  2465 replacing make_keylist and keyfilter (occassionally used)
  2466 Naive rewrites:
  2467 
  2468   make_keylist = AList.make
  2469   keyfilter = AList.find (op =)
  2470 
  2471 * eq_fst and eq_snd now take explicit equality parameter, thus
  2472   avoiding eqtypes. Naive rewrites:
  2473 
  2474     eq_fst = eq_fst (op =)
  2475     eq_snd = eq_snd (op =)
  2476 
  2477 * Removed deprecated apl and apr (rarely used).
  2478   Naive rewrites:
  2479 
  2480     apl (n, op) =>>= curry op n
  2481     apr (op, m) =>>= fn n => op (n, m)
  2482 
  2483 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2484 provides a reasonably efficient light-weight implementation of sets as
  2485 lists.
  2486 
  2487 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2488 few new operations; existing lookup and update are now curried to
  2489 follow natural argument order (for use with fold etc.);
  2490 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2491 
  2492 * Pure/General: output via the Isabelle channels of
  2493 writeln/warning/error etc. is now passed through Output.output, with a
  2494 hook for arbitrary transformations depending on the print_mode
  2495 (cf. Output.add_mode -- the first active mode that provides a output
  2496 function wins).  Already formatted output may be embedded into further
  2497 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2498 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2499 accommodate easy composition of diagnostic messages etc.  Programmers
  2500 rarely need to care about Output.output or Output.raw at all, with
  2501 some notable exceptions: Output.output is required when bypassing the
  2502 standard channels (writeln etc.), or in token translations to produce
  2503 properly formatted results; Output.raw is required when capturing
  2504 already output material that will eventually be presented to the user
  2505 a second time.  For the default print mode, both Output.output and
  2506 Output.raw have no effect.
  2507 
  2508 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2509 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2510 cumulative results are displayed at the end of a batch session.
  2511 
  2512 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2513 replaced by File.platform_path and File.shell_path (with appropriate
  2514 hooks).  This provides a clean interface for unusual systems where the
  2515 internal and external process view of file names are different.
  2516 
  2517 * Pure: more efficient orders for basic syntactic entities: added
  2518 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2519 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2520 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2521 orders now -- potential INCOMPATIBILITY for code that depends on a
  2522 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2523 Library.sort_strings on result).
  2524 
  2525 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2526 fold_types traverse types/terms from left to right, observing natural
  2527 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2528 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2529 
  2530 * Pure: name spaces have been refined, with significant changes of the
  2531 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2532 to extern(_table).  The plain name entry path is superceded by a
  2533 general 'naming' context, which also includes the 'policy' to produce
  2534 a fully qualified name and external accesses of a fully qualified
  2535 name; NameSpace.extend is superceded by context dependent
  2536 Sign.declare_name.  Several theory and proof context operations modify
  2537 the naming context.  Especially note Theory.restore_naming and
  2538 ProofContext.restore_naming to get back to a sane state; note that
  2539 Theory.add_path is no longer sufficient to recover from
  2540 Theory.absolute_path in particular.
  2541 
  2542 * Pure: new flags short_names (default false) and unique_names
  2543 (default true) for controlling output of qualified names.  If
  2544 short_names is set, names are printed unqualified.  If unique_names is
  2545 reset, the name prefix is reduced to the minimum required to achieve
  2546 the original result when interning again, even if there is an overlap
  2547 with earlier declarations.
  2548 
  2549 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2550 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2551 (useful for printing error messages).  INCOMPATIBILITY.
  2552 
  2553 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2554 Theory.theory are now identified, referring to the universal
  2555 Context.theory (see Pure/context.ML).  Actual signature and theory
  2556 content is managed as theory data.  The old code and interfaces were
  2557 spread over many files and structures; the new arrangement introduces
  2558 considerable INCOMPATIBILITY to gain more clarity:
  2559 
  2560   Context -- theory management operations (name, identity, inclusion,
  2561     parents, ancestors, merge, etc.), plus generic theory data;
  2562 
  2563   Sign -- logical signature and syntax operations (declaring consts,
  2564     types, etc.), plus certify/read for common entities;
  2565 
  2566   Theory -- logical theory operations (stating axioms, definitions,
  2567     oracles), plus a copy of logical signature operations (consts,
  2568     types, etc.); also a few basic management operations (Theory.copy,
  2569     Theory.merge, etc.)
  2570 
  2571 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2572 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2573 for convenience -- they merely return the theory.
  2574 
  2575 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2576 
  2577 * Pure: the Isar proof context type is already defined early in Pure
  2578 as Context.proof (note that ProofContext.context and Proof.context are
  2579 aliases, where the latter is the preferred name).  This enables other
  2580 Isabelle components to refer to that type even before Isar is present.
  2581 
  2582 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2583 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2584 any of these kinds.  For example, Sign.intern typeK is now
  2585 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2586 Theory.hide_types.  Also note that former
  2587 Theory.hide_classes/types/consts are now
  2588 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2589 internalize their arguments!  INCOMPATIBILITY.
  2590 
  2591 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2592 datatype thmref (with constructors Name and NameSelection) instead of
  2593 plain string -- INCOMPATIBILITY;
  2594 
  2595 * Pure: cases produced by proof methods specify options, where NONE
  2596 means to remove case bindings -- INCOMPATIBILITY in
  2597 (RAW_)METHOD_CASES.
  2598 
  2599 * Pure: the following operations retrieve axioms or theorems from a
  2600 theory node or theory hierarchy, respectively:
  2601 
  2602   Theory.axioms_of: theory -> (string * term) list
  2603   Theory.all_axioms_of: theory -> (string * term) list
  2604   PureThy.thms_of: theory -> (string * thm) list
  2605   PureThy.all_thms_of: theory -> (string * thm) list
  2606 
  2607 * Pure: print_tac now outputs the goal through the trace channel.
  2608 
  2609 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2610 Reference Toplevel.debug (default false) controls detailed printing
  2611 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2612 controls execution profiling -- set to 1 for time and 2 for space
  2613 (both increase the runtime).
  2614 
  2615 * Isar session: The initial use of ROOT.ML is now always timed,
  2616 i.e. the log will show the actual process times, in contrast to the
  2617 elapsed wall-clock time that the outer shell wrapper produces.
  2618 
  2619 * Simplifier: improved handling of bound variables (nameless
  2620 representation, avoid allocating new strings).  Simprocs that invoke
  2621 the Simplifier recursively should use Simplifier.inherit_bounds to
  2622 avoid local name clashes.  Failure to do so produces warnings
  2623 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2624 for further details.
  2625 
  2626 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2627 bindings for all theorems stored within a given theory; this may help
  2628 in porting non-Isar theories to Isar ones, while keeping ML proof
  2629 scripts for the time being.
  2630 
  2631 * ML operator HTML.with_charset specifies the charset begin used for
  2632 generated HTML files.  For example:
  2633 
  2634   HTML.with_charset "utf-8" use_thy "Hebrew";
  2635   HTML.with_charset "utf-8" use_thy "Chinese";
  2636 
  2637 
  2638 *** System ***
  2639 
  2640 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2641 isabelle, isatool etc.).
  2642 
  2643 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2644 isatool doc, isatool mkdir, display_drafts etc.).
  2645 
  2646 * isatool usedir: option -f allows specification of the ML file to be
  2647 used by Isabelle; default is ROOT.ML.
  2648 
  2649 * New isatool version outputs the version identifier of the Isabelle
  2650 distribution being used.
  2651 
  2652 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2653 (containing Boolean satisfiability problems) into Isabelle/HOL
  2654 theories.
  2655 
  2656 
  2657 
  2658 New in Isabelle2004 (April 2004)
  2659 --------------------------------
  2660 
  2661 *** General ***
  2662 
  2663 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2664   Replaces linorder.ML.
  2665 
  2666 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2667   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2668   (\<a>...\<z>), are now considered normal letters, and can therefore
  2669   be used anywhere where an ASCII letter (a...zA...Z) has until
  2670   now. COMPATIBILITY: This obviously changes the parsing of some
  2671   terms, especially where a symbol has been used as a binder, say
  2672   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2673   as an identifier.  Fix it by inserting a space around former
  2674   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2675   existing theory and ML files.
  2676 
  2677 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2678 
  2679 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2680   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2681   a normal (but invisible) letter. For multiple letter subscripts repeat
  2682   \<^isub> like this: x\<^isub>1\<^isub>2.
  2683 
  2684 * Pure: There are now sub-/superscripts that can span more than one
  2685   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2686   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2687   superscript. The new control characters are not identifier parts.
  2688 
  2689 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2690   content of "..." to the latex file instead of \isacntrl... . The "..."
  2691   may consist of any printable characters excluding the end bracket >.
  2692 
  2693 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2694   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2695   declare constants "final", which prevents their being given a definition
  2696   later.  It is useful for constants whose behaviour is fixed axiomatically
  2697   rather than definitionally, such as the meta-logic connectives.
  2698 
  2699 * Pure: 'instance' now handles general arities with general sorts
  2700   (i.e. intersections of classes),
  2701 
  2702 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2703   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2704   It can be changed to alter the colors/layout of generated pages.
  2705 
  2706 
  2707 *** Isar ***
  2708 
  2709 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2710   cut_tac, subgoal_tac and thin_tac:
  2711   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2712     locales are no longer forced to write Isar proof scripts.
  2713     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2714     emulations.
  2715   - INCOMPATIBILITY: names of variables to be instantiated may no
  2716     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2717     This is consistent with the instantiation attribute "where".
  2718 
  2719 * Attributes "where" and "of":
  2720   - Now take type variables of instantiated theorem into account when reading
  2721     the instantiation string.  This fixes a bug that caused instantiated
  2722     theorems to have too special types in some circumstances.
  2723   - "where" permits explicit instantiations of type variables.
  2724 
  2725 * Calculation commands "moreover" and "also" no longer interfere with
  2726   current facts ("this"), admitting arbitrary combinations with "then"
  2727   and derived forms.
  2728 
  2729 * Locales:
  2730   - Goal statements involving the context element "includes" no longer
  2731     generate theorems with internal delta predicates (those ending on
  2732     "_axioms") in the premise.
  2733     Resolve particular premise with <locale>.intro to obtain old form.
  2734   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2735     specification and "includes" elements in goal statement.
  2736   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2737     [intro?] and [elim?] (respectively) by default.
  2738   - Experimental command for instantiation of locales in proof contexts:
  2739         instantiate <label>[<attrs>]: <loc>
  2740     Instantiates locale <loc> and adds all its theorems to the current context
  2741     taking into account their attributes.  Label and attrs are optional
  2742     modifiers, like in theorem declarations.  If present, names of
  2743     instantiated theorems are qualified with <label>, and the attributes
  2744     <attrs> are applied after any attributes these theorems might have already.
  2745       If the locale has assumptions, a chained fact of the form
  2746     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2747     are derived.  The command does not support old-style locales declared
  2748     with "locale (open)".
  2749       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2750 
  2751 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2752   (Isar) contexts.
  2753 
  2754 
  2755 *** HOL ***
  2756 
  2757 * Proof import: new image HOL4 contains the imported library from
  2758   the HOL4 system with about 2500 theorems. It is imported by
  2759   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2760   can be used like any other Isabelle image.  See
  2761   HOL/Import/HOL/README for more information.
  2762 
  2763 * Simplifier:
  2764   - Much improved handling of linear and partial orders.
  2765     Reasoners for linear and partial orders are set up for type classes
  2766     "linorder" and "order" respectively, and are added to the default simpset
  2767     as solvers.  This means that the simplifier can build transitivity chains
  2768     to solve goals from the assumptions.
  2769   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2770     of blast or auto after simplification become unnecessary because the goal
  2771     is solved by simplification already.
  2772 
  2773 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2774     all proved in axiomatic type classes for semirings, rings and fields.
  2775 
  2776 * Numerics:
  2777   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2778     now formalized using the Ring_and_Field theory mentioned above.
  2779   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2780     than before, because now they are set up once in a generic manner.
  2781   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2782     Look for the general versions in Ring_and_Field (and Power if they concern
  2783     exponentiation).
  2784 
  2785 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2786 
  2787 * Records:
  2788   - Record types are now by default printed with their type abbreviation
  2789     instead of the list of all field types. This can be configured via
  2790     the reference "print_record_type_abbr".
  2791   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2792     (not enabled by default).
  2793   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2794     EX x. x = sel r to True (not enabled by default).
  2795   - Tactic "record_split_simp_tac" to split and simplify records added.
  2796 
  2797 * 'specification' command added, allowing for definition by
  2798   specification.  There is also an 'ax_specification' command that
  2799   introduces the new constants axiomatically.
  2800 
  2801 * arith(_tac) is now able to generate counterexamples for reals as well.
  2802 
  2803 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2804 
  2805 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2806   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2807 
  2808 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2809   matrix theory to linear programming.
  2810 
  2811 * Unions and Intersections:
  2812   The latex output syntax of UN and INT has been changed
  2813   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2814   i.e. the index formulae has become a subscript.
  2815   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2816 
  2817 * Unions and Intersections over Intervals:
  2818   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2819   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2820   like in normal math, and corresponding versions for < and for intersection.
  2821 
  2822 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2823   lexicographic dictonary ordering has been added as "lexord".
  2824 
  2825 * ML: the legacy theory structures Int and List have been removed. They had
  2826   conflicted with ML Basis Library structures having the same names.
  2827 
  2828 * 'refute' command added to search for (finite) countermodels.  Only works
  2829   for a fragment of HOL.  The installation of an external SAT solver is
  2830   highly recommended.  See "HOL/Refute.thy" for details.
  2831 
  2832 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2833   formulae under an assignment of free variables to random values.
  2834   In contrast to 'refute', it can deal with inductive datatypes,
  2835   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2836   for examples.
  2837 
  2838 
  2839 *** HOLCF ***
  2840 
  2841 * Streams now come with concatenation and are part of the HOLCF image
  2842 
  2843 
  2844 
  2845 New in Isabelle2003 (May 2003)
  2846 ------------------------------
  2847 
  2848 *** General ***
  2849 
  2850 * Provers/simplifier:
  2851 
  2852   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2853     Assumptions are now subject to complete mutual simplification,
  2854     not just from left to right. The simplifier now preserves
  2855     the order of assumptions.
  2856 
  2857     Potential INCOMPATIBILITY:
  2858 
  2859     -- simp sometimes diverges where the old version did
  2860        not, e.g. invoking simp on the goal
  2861 
  2862         [| P (f x); y = x; f x = f y |] ==> Q
  2863 
  2864        now gives rise to the infinite reduction sequence
  2865 
  2866         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2867 
  2868        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2869        kind of problem.
  2870 
  2871     -- Tactics combining classical reasoner and simplification (such as auto)
  2872        are also affected by this change, because many of them rely on
  2873        simp. They may sometimes diverge as well or yield a different numbers
  2874        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2875        in case of problems. Sometimes subsequent calls to the classical
  2876        reasoner will fail because a preceeding call to the simplifier too
  2877        eagerly simplified the goal, e.g. deleted redundant premises.
  2878 
  2879   - The simplifier trace now shows the names of the applied rewrite rules
  2880 
  2881   - You can limit the number of recursive invocations of the simplifier
  2882     during conditional rewriting (where the simplifie tries to solve the
  2883     conditions before applying the rewrite rule):
  2884     ML "simp_depth_limit := n"
  2885     where n is an integer. Thus you can force termination where previously
  2886     the simplifier would diverge.
  2887 
  2888   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2889 
  2890   - No longer aborts on failed congruence proof.  Instead, the
  2891     congruence is ignored.
  2892 
  2893 * Pure: New generic framework for extracting programs from constructive
  2894   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2895   as HOL/Extraction for some case studies.
  2896 
  2897 * Pure: The main goal of the proof state is no longer shown by default, only
  2898 the subgoals. This behaviour is controlled by a new flag.
  2899    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2900 (ML: Proof.show_main_goal).
  2901 
  2902 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2903 rules whose conclusion matches subgoal 1:
  2904       PG menu: Isabelle/Isar -> Show me -> matching rules
  2905 The rules are ordered by how closely they match the subgoal.
  2906 In particular, rules that solve a subgoal outright are displayed first
  2907 (or rather last, the way they are printed).
  2908 (ML: ProofGeneral.print_intros())
  2909 
  2910 * Pure: New flag trace_unify_fail causes unification to print
  2911 diagnostic information (PG: in trace buffer) when it fails. This is
  2912 useful for figuring out why single step proofs like rule, erule or
  2913 assumption failed.
  2914 
  2915 * Pure: Locale specifications now produce predicate definitions
  2916 according to the body of text (covering assumptions modulo local
  2917 definitions); predicate "loc_axioms" covers newly introduced text,
  2918 while "loc" is cumulative wrt. all included locale expressions; the
  2919 latter view is presented only on export into the global theory
  2920 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2921 on the old view without predicates;
  2922 
  2923 * Pure: predefined locales "var" and "struct" are useful for sharing
  2924 parameters (as in CASL, for example); just specify something like
  2925 ``var x + var y + struct M'' as import;
  2926 
  2927 * Pure: improved thms_containing: proper indexing of facts instead of
  2928 raw theorems; check validity of results wrt. current name space;
  2929 include local facts of proof configuration (also covers active
  2930 locales), cover fixed variables in index; may use "_" in term
  2931 specification; an optional limit for the number of printed facts may
  2932 be given (the default is 40);
  2933 
  2934 * Pure: disallow duplicate fact bindings within new-style theory files
  2935 (batch-mode only);
  2936 
  2937 * Provers: improved induct method: assumptions introduced by case
  2938 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2939 the goal statement); "foo" still refers to all facts collectively;
  2940 
  2941 * Provers: the function blast.overloaded has been removed: all constants
  2942 are regarded as potentially overloaded, which improves robustness in exchange
  2943 for slight decrease in efficiency;
  2944 
  2945 * Provers/linorder: New generic prover for transitivity reasoning over
  2946 linear orders.  Note: this prover is not efficient!
  2947 
  2948 * Isar: preview of problems to finish 'show' now produce an error
  2949 rather than just a warning (in interactive mode);
  2950 
  2951 
  2952 *** HOL ***
  2953 
  2954 * arith(_tac)
  2955 
  2956  - Produces a counter example if it cannot prove a goal.
  2957    Note that the counter example may be spurious if the goal is not a formula
  2958    of quantifier-free linear arithmetic.
  2959    In ProofGeneral the counter example appears in the trace buffer.
  2960 
  2961  - Knows about div k and mod k where k is a numeral of type nat or int.
  2962 
  2963  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2964    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2965    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2966 
  2967 * simp's arithmetic capabilities have been enhanced a bit: it now
  2968 takes ~= in premises into account (by performing a case split);
  2969 
  2970 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2971 are distributed over a sum of terms;
  2972 
  2973 * New tactic "trans_tac" and method "trans" instantiate
  2974 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2975 "<=", "<" and "=").
  2976 
  2977 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2978 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2979 
  2980 * 'typedef' command has new option "open" to suppress the set
  2981 definition;
  2982 
  2983 * functions Min and Max on finite sets have been introduced (theory
  2984 Finite_Set);
  2985 
  2986 * attribute [symmetric] now works for relations as well; it turns
  2987 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2988 
  2989 * induct over a !!-quantified statement (say !!x1..xn):
  2990   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2991 
  2992 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2993 %x. None. Warning: empty_def now refers to the previously hidden definition
  2994 of the empty set.
  2995 
  2996 * Algebra: formalization of classical algebra.  Intended as base for
  2997 any algebraic development in Isabelle.  Currently covers group theory
  2998 (up to Sylow's theorem) and ring theory (Universal Property of
  2999 Univariate Polynomials).  Contributions welcome;
  3000 
  3001 * GroupTheory: deleted, since its material has been moved to Algebra;
  3002 
  3003 * Complex: new directory of the complex numbers with numeric constants,
  3004 nonstandard complex numbers, and some complex analysis, standard and
  3005 nonstandard (Jacques Fleuriot);
  3006 
  3007 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3008 
  3009 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3010 Fleuriot);
  3011 
  3012 * Real/HahnBanach: updated and adapted to locales;
  3013 
  3014 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3015 Gray and Kramer);
  3016 
  3017 * UNITY: added the Meier-Sanders theory of progress sets;
  3018 
  3019 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3020 as abstract algorithms, instantiated to the JVM;
  3021 
  3022 * Bali: Java source language formalization. Type system, operational
  3023 semantics, axiomatic semantics. Supported language features:
  3024 classes, interfaces, objects,virtual methods, static methods,
  3025 static/instance fields, arrays, access modifiers, definite
  3026 assignment, exceptions.
  3027 
  3028 
  3029 *** ZF ***
  3030 
  3031 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3032 universe, etc.);
  3033 
  3034 * Main ZF: virtually all theories converted to new-style format;
  3035 
  3036 
  3037 *** ML ***
  3038 
  3039 * Pure: Tactic.prove provides sane interface for internal proofs;
  3040 omits the infamous "standard" operation, so this is more appropriate
  3041 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3042 
  3043 * Pure: improved error reporting of simprocs;
  3044 
  3045 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3046 up simprocs;
  3047 
  3048 
  3049 *** Document preparation ***
  3050 
  3051 * uses \par instead of \\ for line breaks in theory text. This may
  3052 shift some page breaks in large documents. To get the old behaviour
  3053 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3054 
  3055 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3056 other packages
  3057 
  3058 * \<euro> now needs package babel/greek instead of marvosym (which
  3059 broke \Rightarrow)
  3060 
  3061 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3062 textcomp package)
  3063 
  3064 
  3065 
  3066 New in Isabelle2002 (March 2002)
  3067 --------------------------------
  3068 
  3069 *** Document preparation ***
  3070 
  3071 * greatly simplified document preparation setup, including more
  3072 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3073 instructive isatool mkdir; users should basically be able to get
  3074 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3075 users may run a separate document processing stage manually like this:
  3076 "isatool usedir -D output HOL Test && isatool document Test/output";
  3077 
  3078 * theory dependency graph may now be incorporated into documents;
  3079 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3080 with \includegraphics of LaTeX;
  3081 
  3082 * proper spacing of consecutive markup elements, especially text
  3083 blocks after section headings;
  3084 
  3085 * support bold style (for single symbols only), input syntax is like
  3086 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3087 
  3088 * \<bullet> is now output as bold \cdot by default, which looks much
  3089 better in printed text;
  3090 
  3091 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3092 note that these symbols are currently unavailable in Proof General /
  3093 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3094 
  3095 * isatool latex no longer depends on changed TEXINPUTS, instead
  3096 isatool document copies the Isabelle style files to the target
  3097 location;
  3098 
  3099 
  3100 *** Isar ***
  3101 
  3102 * Pure/Provers: improved proof by cases and induction;
  3103   - 'case' command admits impromptu naming of parameters (such as
  3104     "case (Suc n)");
  3105   - 'induct' method divinates rule instantiation from the inductive
  3106     claim; no longer requires excessive ?P bindings for proper
  3107     instantiation of cases;
  3108   - 'induct' method properly enumerates all possibilities of set/type
  3109     rules; as a consequence facts may be also passed through *type*
  3110     rules without further ado;
  3111   - 'induct' method now derives symbolic cases from the *rulified*
  3112     rule (before it used to rulify cases stemming from the internal
  3113     atomized version); this means that the context of a non-atomic
  3114     statement becomes is included in the hypothesis, avoiding the
  3115     slightly cumbersome show "PROP ?case" form;
  3116   - 'induct' may now use elim-style induction rules without chaining
  3117     facts, using ``missing'' premises from the goal state; this allows
  3118     rules stemming from inductive sets to be applied in unstructured
  3119     scripts, while still benefitting from proper handling of non-atomic
  3120     statements; NB: major inductive premises need to be put first, all
  3121     the rest of the goal is passed through the induction;
  3122   - 'induct' proper support for mutual induction involving non-atomic
  3123     rule statements (uses the new concept of simultaneous goals, see
  3124     below);
  3125   - append all possible rule selections, but only use the first
  3126     success (no backtracking);
  3127   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3128   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3129   - added 'print_induct_rules' (covered by help item in recent Proof
  3130     General versions);
  3131   - moved induct/cases attributes to Pure, methods to Provers;
  3132   - generic method setup instantiated for FOL and HOL;
  3133 
  3134 * Pure: support multiple simultaneous goal statements, for example
  3135 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3136 meta-level mechanism, this acts as if several individual goals had
  3137 been stated separately; in particular common proof methods need to be
  3138 repeated in order to cover all claims; note that a single elimination
  3139 step is *not* sufficient to establish the two conjunctions, so this
  3140 fails:
  3141 
  3142   assume "A & B" then have A and B ..   (*".." fails*)
  3143 
  3144 better use "obtain" in situations as above; alternative refer to
  3145 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3146 
  3147 * Pure: proper integration with ``locales''; unlike the original
  3148 version by Florian Kammller, Isar locales package high-level proof
  3149 contexts rather than raw logical ones (e.g. we admit to include
  3150 attributes everywhere); operations on locales include merge and
  3151 rename; support for implicit arguments (``structures''); simultaneous
  3152 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3153 some examples;
  3154 
  3155 * Pure: the following commands have been ``localized'', supporting a
  3156 target locale specification "(in name)": 'lemma', 'theorem',
  3157 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3158 stored both within the locale and at the theory level (exported and
  3159 qualified by the locale name);
  3160 
  3161 * Pure: theory goals may now be specified in ``long'' form, with
  3162 ad-hoc contexts consisting of arbitrary locale elements. for example
  3163 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3164 definitions may be given, too); the result is a meta-level rule with
  3165 the context elements being discharged in the obvious way;
  3166 
  3167 * Pure: new proof command 'using' allows to augment currently used
  3168 facts after a goal statement ('using' is syntactically analogous to
  3169 'apply', but acts on the goal's facts only); this allows chained facts
  3170 to be separated into parts given before and after a claim, as in
  3171 ``from a and b have C using d and e <proof>'';
  3172 
  3173 * Pure: renamed "antecedent" case to "rule_context";
  3174 
  3175 * Pure: new 'judgment' command records explicit information about the
  3176 object-logic embedding (used by several tools internally); no longer
  3177 use hard-wired "Trueprop";
  3178 
  3179 * Pure: added 'corollary' command;
  3180 
  3181 * Pure: fixed 'token_translation' command;
  3182 
  3183 * Pure: removed obsolete 'exported' attribute;
  3184 
  3185 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3186 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3187 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3188 
  3189 * Pure: method 'atomize' presents local goal premises as object-level
  3190 statements (atomic meta-level propositions); setup controlled via
  3191 rewrite rules declarations of 'atomize' attribute; example
  3192 application: 'induct' method with proper rule statements in improper
  3193 proof *scripts*;
  3194 
  3195 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3196 now consider the syntactic context of assumptions, giving a better
  3197 chance to get type-inference of the arguments right (this is
  3198 especially important for locales);
  3199 
  3200 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3201 mode;
  3202 
  3203 * Pure/obtain: the formal conclusion "thesis", being marked as
  3204 ``internal'', may no longer be reference directly in the text;
  3205 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3206 situations;
  3207 
  3208 * Pure: generic 'sym' attribute which declares a rule both as pure
  3209 'elim?' and for the 'symmetric' operation;
  3210 
  3211 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3212 text; the fixed correlation with particular command syntax has been
  3213 discontinued;
  3214 
  3215 * Pure: new method 'rules' is particularly well-suited for proof
  3216 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3217 but often produces more compact proof terms with less detours;
  3218 
  3219 * Pure/Provers/classical: simplified integration with pure rule
  3220 attributes and methods; the classical "intro?/elim?/dest?"
  3221 declarations coincide with the pure ones; the "rule" method no longer
  3222 includes classically swapped intros; "intro" and "elim" methods no
  3223 longer pick rules from the context; also got rid of ML declarations
  3224 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3225 INCOMPATIBILITY;
  3226 
  3227 * Provers/classical: attribute 'swapped' produces classical inversions
  3228 of introduction rules;
  3229 
  3230 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3231 rules instead of full simplifier context; 'iff' attribute handles
  3232 conditional rules;
  3233 
  3234 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3235 
  3236 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3237 "(permissive)" option to recover old behavior;
  3238 
  3239 * HOL: 'inductive' no longer features separate (collective) attributes
  3240 for 'intros' (was found too confusing);
  3241 
  3242 * HOL: properly declared induction rules less_induct and
  3243 wf_induct_rule;
  3244 
  3245 
  3246 *** HOL ***
  3247 
  3248 * HOL: moved over to sane numeral syntax; the new policy is as
  3249 follows:
  3250 
  3251   - 0 and 1 are polymorphic constants, which are defined on any
  3252   numeric type (nat, int, real etc.);
  3253 
  3254   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3255   binary representation internally;
  3256 
  3257   - type nat has special constructor Suc, and generally prefers Suc 0
  3258   over 1::nat and Suc (Suc 0) over 2::nat;
  3259 
  3260 This change may cause significant problems of INCOMPATIBILITY; here
  3261 are some hints on converting existing sources:
  3262 
  3263   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3264   entities, so expressions involving "-" (unary or binary minus) need
  3265   to be spaced properly;
  3266 
  3267   - existing occurrences of "1" may need to be constraint "1::nat" or
  3268   even replaced by Suc 0; similar for old "2";
  3269 
  3270   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3271 
  3272   - remove all special provisions on numerals in proofs;
  3273 
  3274 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3275 representation (depends on bin_arith_simps in the default context);
  3276 
  3277 * HOL: symbolic syntax for x^2 (numeral 2);
  3278 
  3279 * HOL: the class of all HOL types is now called "type" rather than
  3280 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3281 in axclass/classes, instance/arities, and (usually rare) occurrences
  3282 in typings (of consts etc.); internally the class is called
  3283 "HOL.type", ML programs should refer to HOLogic.typeS;
  3284 
  3285 * HOL/record package improvements:
  3286   - new derived operations "fields" to build a partial record section,
  3287     "extend" to promote a fixed record to a record scheme, and
  3288     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3289     declared as simp by default;
  3290   - shared operations ("more", "fields", etc.) now need to be always
  3291     qualified) --- potential INCOMPATIBILITY;
  3292   - removed "make_scheme" operations (use "make" with "extend") --
  3293     INCOMPATIBILITY;
  3294   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3295   - provides cases/induct rules for use with corresponding Isar
  3296     methods (for concrete records, record schemes, concrete more
  3297     parts, and schematic more parts -- in that order);
  3298   - internal definitions directly based on a light-weight abstract
  3299     theory of product types over typedef rather than datatype;
  3300 
  3301 * HOL: generic code generator for generating executable ML code from
  3302 specifications; specific support for HOL constructs such as inductive
  3303 datatypes and sets, as well as recursive functions; can be invoked
  3304 via 'generate_code' theory section;
  3305 
  3306 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3307 
  3308 * HOL: consolidated and renamed several theories.  In particular:
  3309         Ord.thy has been absorbed into HOL.thy
  3310         String.thy has been absorbed into List.thy
  3311 
  3312 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3313 (beware of argument permutation!);
  3314 
  3315 * HOL: linorder_less_split superseded by linorder_cases;
  3316 
  3317 * HOL/List: "nodups" renamed to "distinct";
  3318 
  3319 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3320 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3321   - Ex_def has changed, now need to use some_eq_ex
  3322 
  3323 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3324 in this (rare) case use:
  3325 
  3326   delSWrapper "split_all_tac"
  3327   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3328 
  3329 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3330 MAY FAIL;
  3331 
  3332 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3333 Isabelle's type classes, ^ on functions and relations has too general
  3334 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3335 necessary to attach explicit type constraints;
  3336 
  3337 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3338 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3339 renamed accordingly (eg "compI" -> "rel_compI").
  3340 
  3341 * HOL: syntax translations now work properly with numerals and records
  3342 expressions;
  3343 
  3344 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3345 of "lam" -- INCOMPATIBILITY;
  3346 
  3347 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3348 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3349 renamed "Product_Type.unit";
  3350 
  3351 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3352 
  3353 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3354 the "cases" method);
  3355 
  3356 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3357 Florian Kammller);
  3358 
  3359 * HOL/IMP: updated and converted to new-style theory format; several
  3360 parts turned into readable document, with proper Isar proof texts and
  3361 some explanations (by Gerwin Klein);
  3362 
  3363 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3364 
  3365 * HOL-Hyperreal is now a logic image;
  3366 
  3367 
  3368 *** HOLCF ***
  3369 
  3370 * Isar: consts/constdefs supports mixfix syntax for continuous
  3371 operations;
  3372 
  3373 * Isar: domain package adapted to new-style theory format, e.g. see
  3374 HOLCF/ex/Dnat.thy;
  3375 
  3376 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3377 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3378 lift.induct_tac, always use UU instead of Undef;
  3379 
  3380 * HOLCF/IMP: updated and converted to new-style theory;
  3381 
  3382 
  3383 *** ZF ***
  3384 
  3385 * Isar: proper integration of logic-specific tools and packages,
  3386 including theory commands '(co)inductive', '(co)datatype',
  3387 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3388 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3389 
  3390 * theory Main no longer includes AC; for the Axiom of Choice, base
  3391 your theory on Main_ZFC;
  3392 
  3393 * the integer library now covers quotients and remainders, with many
  3394 laws relating division to addition, multiplication, etc.;
  3395 
  3396 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3397 typeless version of the formalism;
  3398 
  3399 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3400 format;
  3401 
  3402 * ZF/Induct: new directory for examples of inductive definitions,
  3403 including theory Multiset for multiset orderings; converted to
  3404 new-style theory format;
  3405 
  3406 * ZF: many new theorems about lists, ordinals, etc.;
  3407 
  3408 
  3409 *** General ***
  3410 
  3411 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3412 variable proof controls level of detail: 0 = no proofs (only oracle
  3413 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3414 also ref manual for further ML interfaces;
  3415 
  3416 * Pure/axclass: removed obsolete ML interface
  3417 goal_subclass/goal_arity;
  3418 
  3419 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3420 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3421 separate tokens, so expressions involving minus need to be spaced
  3422 properly;
  3423 
  3424 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3425 rather than "infixl" or "infixr";
  3426 
  3427 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3428 sort constraint specifications in type inference; e.g. "x::_::foo"
  3429 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3430 type variable);
  3431 
  3432 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3433 control output of nested => (types); the default behavior is
  3434 "type_brackets";
  3435 
  3436 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3437 tokens into AST constants;
  3438 
  3439 * Pure/syntax: prefer later declarations of translations and print
  3440 translation functions; potential INCOMPATIBILITY: need to reverse
  3441 multiple declarations for same syntax element constant;
  3442 
  3443 * Pure/show_hyps reset by default (in accordance to existing Isar
  3444 practice);
  3445 
  3446 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3447 addSafter;
  3448 
  3449 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3450 as well;
  3451 
  3452 * system: tested support for MacOS X; should be able to get Isabelle +
  3453 Proof General to work in a plain Terminal after installing Poly/ML
  3454 (e.g. from the Isabelle distribution area) and GNU bash alone
  3455 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3456 support requires further installations, e.g. from
  3457 http://fink.sourceforge.net/);
  3458 
  3459 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3460 
  3461 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3462 of 40 MB), cf. ML_OPTIONS;
  3463 
  3464 * system: Proof General keywords specification is now part of the
  3465 Isabelle distribution (see etc/isar-keywords.el);
  3466 
  3467 * system: support for persistent Proof General sessions (refrain from
  3468 outdating all loaded theories on startup); user may create writable
  3469 logic images like this: ``isabelle -q HOL Test'';
  3470 
  3471 * system: smart selection of Isabelle process versus Isabelle
  3472 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3473 run both "isabelle" and "Isabelle" even if file names are badly
  3474 damaged (executable inspects the case of the first letter of its own
  3475 name); added separate "isabelle-process" and "isabelle-interface";
  3476 
  3477 * system: refrain from any attempt at filtering input streams; no
  3478 longer support ``8bit'' encoding of old isabelle font, instead proper
  3479 iso-latin characters may now be used; the related isatools
  3480 "symbolinput" and "nonascii" have disappeared as well;
  3481 
  3482 * system: removed old "xterm" interface (the print modes "xterm" and
  3483 "xterm_color" are still available for direct use in a suitable
  3484 terminal);
  3485 
  3486 
  3487 
  3488 New in Isabelle99-2 (February 2001)
  3489 -----------------------------------
  3490 
  3491 *** Overview of INCOMPATIBILITIES ***
  3492 
  3493 * HOL: please note that theories in the Library and elsewhere often use the
  3494 new-style (Isar) format; to refer to their theorems in an ML script you must
  3495 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3496 
  3497 * HOL: inductive package no longer splits induction rule aggressively,
  3498 but only as far as specified by the introductions given; the old
  3499 format may be recovered via ML function complete_split_rule or attribute
  3500 'split_rule (complete)';
  3501 
  3502 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3503 gfp_Tarski to gfp_unfold;
  3504 
  3505 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3506 
  3507 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3508 relation); infix "^^" has been renamed "``"; infix "``" has been
  3509 renamed "`"; "univalent" has been renamed "single_valued";
  3510 
  3511 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3512 operation;
  3513 
  3514 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3515 
  3516 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3517 
  3518 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3519 consequence, it is no longer monotonic wrt. the local goal context
  3520 (which is now passed through the inductive cases);
  3521 
  3522 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3523 \<gg> to \<ggreater>;
  3524 
  3525 
  3526 *** Document preparation ***
  3527 
  3528 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3529 available: are "it" for near math-mode best-style output, "sl" for
  3530 slanted text style, and "tt" for plain type-writer; if no
  3531 \isabellestyle command is given, output is according to slanted
  3532 type-writer);
  3533 
  3534 * support sub/super scripts (for single symbols only), input syntax is
  3535 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3536 
  3537 * some more standard symbols; see Appendix A of the system manual for
  3538 the complete list of symbols defined in isabellesym.sty;
  3539 
  3540 * improved isabelle style files; more abstract symbol implementation
  3541 (should now use \isamath{...} and \isatext{...} in custom symbol
  3542 definitions);
  3543 
  3544 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3545 state; Note that presentation of goal states does not conform to
  3546 actual human-readable proof documents.  Please do not include goal
  3547 states into document output unless you really know what you are doing!
  3548 
  3549 * proper indentation of antiquoted output with proportional LaTeX
  3550 fonts;
  3551 
  3552 * no_document ML operator temporarily disables LaTeX document
  3553 generation;
  3554 
  3555 * isatool unsymbolize tunes sources for plain ASCII communication;
  3556 
  3557 
  3558 *** Isar ***
  3559 
  3560 * Pure: Isar now suffers initial goal statements to contain unbound
  3561 schematic variables (this does not conform to actual readable proof
  3562 documents, due to unpredictable outcome and non-compositional proof
  3563 checking); users who know what they are doing may use schematic goals
  3564 for Prolog-style synthesis of proven results;
  3565 
  3566 * Pure: assumption method (an implicit finishing) now handles actual
  3567 rules as well;
  3568 
  3569 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3570 initial goal, declare "that" only as Pure intro (only for single
  3571 steps); the "that" rule assumption may now be involved in implicit
  3572 finishing, thus ".." becomes a feasible for trivial obtains;
  3573 
  3574 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3575 instance proofs may be performed by "..";
  3576 
  3577 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3578 statements as well;
  3579 
  3580 * Pure: more robust selection of calculational rules;
  3581 
  3582 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3583 rule (as well as the assumption rule);
  3584 
  3585 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3586 lemmas, using the graph browser tool;
  3587 
  3588 * Pure: predict failure of "show" in interactive mode;
  3589 
  3590 * Pure: 'thms_containing' now takes actual terms as arguments;
  3591 
  3592 * HOL: improved method 'induct' --- now handles non-atomic goals
  3593 (potential INCOMPATIBILITY); tuned error handling;
  3594 
  3595 * HOL: cases and induct rules now provide explicit hints about the
  3596 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3597 any remaining facts are inserted into the goal verbatim;
  3598 
  3599 * HOL: local contexts (aka cases) may now contain term bindings as
  3600 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3601 the result to be shown in each case;
  3602 
  3603 * HOL: added 'recdef_tc' command;
  3604 
  3605 * isatool convert assists in eliminating legacy ML scripts;
  3606 
  3607 
  3608 *** HOL ***
  3609 
  3610 * HOL/Library: a collection of generic theories to be used together
  3611 with main HOL; the theory loader path already includes this directory
  3612 by default; the following existing theories have been moved here:
  3613 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3614 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3615 
  3616 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3617 modelling and verification task performed in Isabelle/HOL +
  3618 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3619 
  3620 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3621 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3622 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3623 'domain', this makes the theory consistent with mathematical
  3624 literature;
  3625 
  3626 * HOL basics: added overloaded operations "inverse" and "divide"
  3627 (infix "/"), syntax for generic "abs" operation, generic summation
  3628 operator \<Sum>;
  3629 
  3630 * HOL/typedef: simplified package, provide more useful rules (see also
  3631 HOL/subset.thy);
  3632 
  3633 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3634 now expressed as a proper nested rule (old-style tactic scripts may
  3635 require atomize_strip_tac to cope with non-atomic premises);
  3636 
  3637 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3638 to "split_conv" (old name still available for compatibility);
  3639 
  3640 * HOL: improved concrete syntax for strings (e.g. allows translation
  3641 rules with string literals);
  3642 
  3643 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3644  and Fleuriot's mechanization of analysis, including the transcendental
  3645  functions for the reals;
  3646 
  3647 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3648 
  3649 
  3650 *** CTT ***
  3651 
  3652 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3653 "lam" is displayed as TWO lambda-symbols
  3654 
  3655 * CTT: theory Main now available, containing everything (that is, Bool
  3656 and Arith);
  3657 
  3658 
  3659 *** General ***
  3660 
  3661 * Pure: the Simplifier has been implemented properly as a derived rule
  3662 outside of the actual kernel (at last!); the overall performance
  3663 penalty in practical applications is about 50%, while reliability of
  3664 the Isabelle inference kernel has been greatly improved;
  3665 
  3666 * print modes "brackets" and "no_brackets" control output of nested =>
  3667 (types) and ==> (props); the default behaviour is "brackets";
  3668 
  3669 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3670 as assumptions as well;
  3671 
  3672 * system: support Poly/ML 4.0;
  3673 
  3674 * system: isatool install handles KDE version 1 or 2;
  3675 
  3676 
  3677 
  3678 New in Isabelle99-1 (October 2000)
  3679 ----------------------------------
  3680 
  3681 *** Overview of INCOMPATIBILITIES ***
  3682 
  3683 * HOL: simplification of natural numbers is much changed; to partly
  3684 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3685 issue the following ML commands:
  3686 
  3687   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3688   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3689 
  3690 * HOL: simplification no longer dives into case-expressions; this is
  3691 controlled by "t.weak_case_cong" for each datatype t;
  3692 
  3693 * HOL: nat_less_induct renamed to less_induct;
  3694 
  3695 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3696 fixsome to patch .thy and .ML sources automatically;
  3697 
  3698   select_equality  -> some_equality
  3699   select_eq_Ex     -> some_eq_ex
  3700   selectI2EX       -> someI2_ex
  3701   selectI2         -> someI2
  3702   selectI          -> someI
  3703   select1_equality -> some1_equality
  3704   Eps_sym_eq       -> some_sym_eq_trivial
  3705   Eps_eq           -> some_eq_trivial
  3706 
  3707 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3708 
  3709 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3710 instead);
  3711 
  3712 * HOL: the recursion equations generated by 'recdef' are now called
  3713 f.simps instead of f.rules;
  3714 
  3715 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3716 
  3717 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3718 sometimes be needed;
  3719 
  3720 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3721 
  3722 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3723 
  3724 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3725 product is now "<*>" instead of "Times"; the lexicographic product is
  3726 now "<*lex*>" instead of "**";
  3727 
  3728 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3729 of main HOL, but was unused); better use HOL's datatype package;
  3730 
  3731 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3732 the old syntax may be recovered as follows:
  3733 
  3734   syntax (symbols)
  3735     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3736       (infixl "\\<oplus>" 100)
  3737 
  3738 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3739 
  3740 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3741 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3742 internally;
  3743 
  3744 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3745 changed from A/r to A//r;
  3746 
  3747 * ZF: new treatment of arithmetic (nat & int) may break some old
  3748 proofs;
  3749 
  3750 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3751 rulify -> rule_format, elimify -> elim_format, ...);
  3752 
  3753 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3754 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3755 should have to change intro!! to intro? only); replaced "delrule" by
  3756 "rule del";
  3757 
  3758 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3759 
  3760 * Provers: strengthened force_tac by using new first_best_tac;
  3761 
  3762 * LaTeX document preparation: several changes of isabelle.sty (see
  3763 lib/texinputs);
  3764 
  3765 
  3766 *** Document preparation ***
  3767 
  3768 * formal comments (text blocks etc.) in new-style theories may now
  3769 contain antiquotations of thm/prop/term/typ/text to be presented
  3770 according to latex print mode; concrete syntax is like this:
  3771 @{term[show_types] "f(x) = a + x"};
  3772 
  3773 * isatool mkdir provides easy setup of Isabelle session directories,
  3774 including proper document sources;
  3775 
  3776 * generated LaTeX sources are now deleted after successful run
  3777 (isatool document -c); may retain a copy somewhere else via -D option
  3778 of isatool usedir;
  3779 
  3780 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3781 style files, achieving self-contained LaTeX sources and simplifying
  3782 LaTeX debugging;
  3783 
  3784 * old-style theories now produce (crude) LaTeX output as well;
  3785 
  3786 * browser info session directories are now self-contained (may be put
  3787 on WWW server seperately); improved graphs of nested sessions; removed
  3788 graph for 'all sessions';
  3789 
  3790 * several improvements in isabelle style files; \isabellestyle{it}
  3791 produces fake math mode output; \isamarkupheader is now \section by
  3792 default; see lib/texinputs/isabelle.sty etc.;
  3793 
  3794 
  3795 *** Isar ***
  3796 
  3797 * Isar/Pure: local results and corresponding term bindings are now
  3798 subject to Hindley-Milner polymorphism (similar to ML); this
  3799 accommodates incremental type-inference very nicely;
  3800 
  3801 * Isar/Pure: new derived language element 'obtain' supports
  3802 generalized existence reasoning;
  3803 
  3804 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3805 support accumulation of results, without applying any rules yet;
  3806 useful to collect intermediate results without explicit name
  3807 references, and for use with transitivity rules with more than 2
  3808 premises;
  3809 
  3810 * Isar/Pure: scalable support for case-analysis type proofs: new
  3811 'case' language element refers to local contexts symbolically, as
  3812 produced by certain proof methods; internally, case names are attached
  3813 to theorems as "tags";
  3814 
  3815 * Isar/Pure: theory command 'hide' removes declarations from
  3816 class/type/const name spaces;
  3817 
  3818 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3819 indicate potential overloading;
  3820 
  3821 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3822 
  3823 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3824 "{a,b,c}" instead of {a,b,c};
  3825 
  3826 * Isar/Pure now provides its own version of intro/elim/dest
  3827 attributes; useful for building new logics, but beware of confusion
  3828 with the version in Provers/classical;
  3829 
  3830 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3831 case name 'antecedent';
  3832 
  3833 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3834 to the current context is now done automatically);
  3835 
  3836 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3837 for definining proof methods in ML;
  3838 
  3839 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3840 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3841 most cases, one should have to change intro!! to intro? only);
  3842 replaced "delrule" by "rule del";
  3843 
  3844 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3845 'symmetric' attribute (the latter supercedes [RS sym]);
  3846 
  3847 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3848 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3849 well (including splits);
  3850 
  3851 * Isar/Provers: Simplifier and Classical methods now support all kind
  3852 of modifiers used in the past, including 'cong', 'iff', etc.
  3853 
  3854 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3855 of Simplifier and Classical reasoner);
  3856 
  3857 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3858 now support named cases; major packages (inductive, datatype, primrec,
  3859 recdef) support case names and properly name parameters;
  3860 
  3861 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3862 monotonicity conditions are extracted to be proven at end of
  3863 calculations;
  3864 
  3865 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3866 method anyway;
  3867 
  3868 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3869 split_if split_if_asm; datatype package provides theorems foo.splits =
  3870 foo.split foo.split_asm for each datatype;
  3871 
  3872 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3873 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3874 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3875 use "(cases (simplified))" method in proper proof texts);
  3876 
  3877 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3878 
  3879 * Isar: names of theorems etc. may be natural numbers as well;
  3880 
  3881 * Isar: 'pr' command: optional arguments for goals_limit and
  3882 ProofContext.prems_limit; no longer prints theory contexts, but only
  3883 proof states;
  3884 
  3885 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3886 additional print modes to be specified; e.g. "pr(latex)" will print
  3887 proof state according to the Isabelle LaTeX style;
  3888 
  3889 * Isar: improved support for emulating tactic scripts, including proof
  3890 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3891 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3892 (for HOL datatypes);
  3893 
  3894 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3895 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3896 'proof method scripts' have to be in depth-first order;
  3897 
  3898 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3899 
  3900 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3901 should instead use individual commands for printing items
  3902 (print_commands, print_methods etc.);
  3903 
  3904 * Isar: added 'nothing' --- the empty list of theorems;
  3905 
  3906 
  3907 *** HOL ***
  3908 
  3909 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3910 corresponding virtual machine and a specification of its bytecode
  3911 verifier and a lightweight bytecode verifier, including proofs of
  3912 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3913 Cornelia Pusch (see also the homepage of project Bali at
  3914 http://isabelle.in.tum.de/Bali/);
  3915 
  3916 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3917 Clemens Ballarin;
  3918 
  3919 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3920 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3921 Rasmussen;
  3922 
  3923 * HOL/Lattice: fundamental concepts of lattice theory and order
  3924 structures, including duals, properties of bounds versus algebraic
  3925 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3926 Theorem for complete lattices etc.; may also serve as a demonstration
  3927 for abstract algebraic reasoning using axiomatic type classes, and
  3928 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3929 
  3930 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3931 von Oheimb;
  3932 
  3933 * HOL/IMPP: extension of IMP with local variables and mutually
  3934 recursive procedures, by David von Oheimb;
  3935 
  3936 * HOL/Lambda: converted into new-style theory and document;
  3937 
  3938 * HOL/ex/Multiquote: example of multiple nested quotations and
  3939 anti-quotations -- basically a generalized version of de-Bruijn
  3940 representation; very useful in avoiding lifting of operations;
  3941 
  3942 * HOL/record: added general record equality rule to simpset; fixed
  3943 select-update simplification procedure to handle extended records as
  3944 well; admit "r" as field name;
  3945 
  3946 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3947 other numeric types and also as the identity of groups, rings, etc.;
  3948 
  3949 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3950 Types nat and int belong to this axclass;
  3951 
  3952 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3953    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3954    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3955   two terms #m*u and #n*u are replaced by #(m+n)*u
  3956     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3957   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3958     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3959 
  3960 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3961 powerful prover for predicate logic but knows nothing of clasets; see
  3962 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3963 
  3964 * HOL: new version of "case_tac" subsumes both boolean case split and
  3965 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3966 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3967 
  3968 * HOL: simplification no longer dives into case-expressions: only the
  3969 selector expression is simplified, but not the remaining arms; to
  3970 enable full simplification of case-expressions for datatype t, you may
  3971 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3972 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3973 
  3974 * HOL/recdef: the recursion equations generated by 'recdef' for
  3975 function 'f' are now called f.simps instead of f.rules; if all
  3976 termination conditions are proved automatically, these simplification
  3977 rules are added to the simpset, as in primrec; rules may be named
  3978 individually as well, resulting in a separate list of theorems for
  3979 each equation;
  3980 
  3981 * HOL/While is a new theory that provides a while-combinator. It
  3982 permits the definition of tail-recursive functions without the
  3983 provision of a termination measure. The latter is necessary once the
  3984 invariant proof rule for while is applied.
  3985 
  3986 * HOL: new (overloaded) notation for the set of elements below/above
  3987 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3988 
  3989 * HOL: theorems impI, allI, ballI bound as "strip";
  3990 
  3991 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3992 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3993 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3994 
  3995 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3996 
  3997 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3998 main HOL, but was unused);
  3999 
  4000 * HOL: fewer consts declared as global (e.g. have to refer to
  4001 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4002 
  4003 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4004 in case of overlap with user translations (e.g. judgements over
  4005 tuples); (note that the underlying logical represenation is still
  4006 bogus);
  4007 
  4008 
  4009 *** ZF ***
  4010 
  4011 * ZF: simplification automatically cancels common terms in arithmetic
  4012 expressions over nat and int;
  4013 
  4014 * ZF: new treatment of nat to minimize type-checking: all operators
  4015 coerce their operands to a natural number using the function natify,
  4016 making the algebraic laws unconditional;
  4017 
  4018 * ZF: as above, for int: operators coerce their operands to an integer
  4019 using the function intify;
  4020 
  4021 * ZF: the integer library now contains many of the usual laws for the
  4022 orderings, including $<=, and monotonicity laws for $+ and $*;
  4023 
  4024 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4025 simplification;
  4026 
  4027 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4028 to the simplifier and classical reasoner simultaneously;
  4029 
  4030 
  4031 *** General ***
  4032 
  4033 * Provers: blast_tac now handles actual object-logic rules as
  4034 assumptions; note that auto_tac uses blast_tac internally as well;
  4035 
  4036 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4037 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4038 
  4039 * Provers: delrules now handles destruct rules as well (no longer need
  4040 explicit make_elim);
  4041 
  4042 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4043   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4044 use instead the strong form,
  4045   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4046 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4047 from destruct-rules;
  4048 
  4049 * Provers: Simplifier.easy_setup provides a fast path to basic
  4050 Simplifier setup for new object-logics;
  4051 
  4052 * Pure: AST translation rules no longer require constant head on LHS;
  4053 
  4054 * Pure: improved name spaces: ambiguous output is qualified; support
  4055 for hiding of names;
  4056 
  4057 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4058 XSYMBOL_HOME; no longer need to do manual configuration in most
  4059 situations;
  4060 
  4061 * system: compression of ML heaps images may now be controlled via -c
  4062 option of isabelle and isatool usedir (currently only observed by
  4063 Poly/ML);
  4064 
  4065 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4066 useful for remote X11);
  4067 
  4068 * system: provide TAGS file for Isabelle sources;
  4069 
  4070 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4071 order;
  4072 
  4073 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4074 timing flag supersedes proof_timing and Toplevel.trace;
  4075 
  4076 * ML: new combinators |>> and |>>> for incremental transformations
  4077 with secondary results (e.g. certain theory extensions):
  4078 
  4079 * ML: PureThy.add_defs gets additional argument to indicate potential
  4080 overloading (usually false);
  4081 
  4082 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4083 results;
  4084 
  4085 
  4086 
  4087 New in Isabelle99 (October 1999)
  4088 --------------------------------
  4089 
  4090 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4091 
  4092 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4093 are no longer simplified.  (This allows the simplifier to unfold recursive
  4094 functional programs.)  To restore the old behaviour, declare
  4095 
  4096     Delcongs [if_weak_cong];
  4097 
  4098 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4099 complement;
  4100 
  4101 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4102 
  4103 * HOL/datatype: mutual_induct_tac no longer exists --
  4104   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4105 
  4106 * HOL/typedef: fixed type inference for representing set; type
  4107 arguments now have to occur explicitly on the rhs as type constraints;
  4108 
  4109 * ZF: The con_defs part of an inductive definition may no longer refer
  4110 to constants declared in the same theory;
  4111 
  4112 * HOL, ZF: the function mk_cases, generated by the inductive
  4113 definition package, has lost an argument.  To simplify its result, it
  4114 uses the default simpset instead of a supplied list of theorems.
  4115 
  4116 * HOL/List: the constructors of type list are now Nil and Cons;
  4117 
  4118 * Simplifier: the type of the infix ML functions
  4119         setSSolver addSSolver setSolver addSolver
  4120 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4121 for packaging solvers. A solver is created via
  4122         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4123 where the string argument is only a comment.
  4124 
  4125 
  4126 *** Proof tools ***
  4127 
  4128 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4129 decision procedure for linear arithmetic. Currently it is used for
  4130 types `nat', `int', and `real' in HOL (see below); it can, should and
  4131 will be instantiated for other types and logics as well.
  4132 
  4133 * The simplifier now accepts rewrite rules with flexible heads, eg
  4134      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4135   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4136   matching.
  4137 
  4138 
  4139 *** General ***
  4140 
  4141 * New Isabelle/Isar subsystem provides an alternative to traditional
  4142 tactical theorem proving; together with the ProofGeneral/isar user
  4143 interface it offers an interactive environment for developing human
  4144 readable proof documents (Isar == Intelligible semi-automated
  4145 reasoning); for further information see isatool doc isar-ref,
  4146 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4147 
  4148 * improved and simplified presentation of theories: better HTML markup
  4149 (including colors), graph views in several sizes; isatool usedir now
  4150 provides a proper interface for user theories (via -P option); actual
  4151 document preparation based on (PDF)LaTeX is available as well (for
  4152 new-style theories only); see isatool doc system for more information;
  4153 
  4154 * native support for Proof General, both for classic Isabelle and
  4155 Isabelle/Isar;
  4156 
  4157 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4158 using the graph browser tool;
  4159 
  4160 * Isabelle manuals now also available as PDF;
  4161 
  4162 * theory loader rewritten from scratch (may not be fully
  4163 bug-compatible); old loadpath variable has been replaced by show_path,
  4164 add_path, del_path, reset_path functions; new operations such as
  4165 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4166 isatool doc ref);
  4167 
  4168 * improved isatool install: option -k creates KDE application icon,
  4169 option -p DIR installs standalone binaries;
  4170 
  4171 * added ML_PLATFORM setting (useful for cross-platform installations);
  4172 more robust handling of platform specific ML images for SML/NJ;
  4173 
  4174 * the settings environment is now statically scoped, i.e. it is never
  4175 created again in sub-processes invoked from isabelle, isatool, or
  4176 Isabelle;
  4177 
  4178 * path element specification '~~' refers to '$ISABELLE_HOME';
  4179 
  4180 * in locales, the "assumes" and "defines" parts may be omitted if
  4181 empty;
  4182 
  4183 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4184 long arrows);
  4185 
  4186 * new print_mode "HTML";
  4187 
  4188 * new flag show_tags controls display of tags of theorems (which are
  4189 basically just comments that may be attached by some tools);
  4190 
  4191 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4192 mode and goal output format:
  4193 
  4194 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4195 244c244
  4196 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4197 ---
  4198 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4199 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4200 181c181
  4201 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4202 ---
  4203 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4204 
  4205 * function bind_thms stores lists of theorems (cf. bind_thm);
  4206 
  4207 * new shorthand tactics ftac, eatac, datac, fatac;
  4208 
  4209 * qed (and friends) now accept "" as result name; in that case the
  4210 theorem is not stored, but proper checks and presentation of the
  4211 result still apply;
  4212 
  4213 * theorem database now also indexes constants "Trueprop", "all",
  4214 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4215 
  4216 
  4217 *** HOL ***
  4218 
  4219 ** HOL arithmetic **
  4220 
  4221 * There are now decision procedures for linear arithmetic over nat and
  4222 int:
  4223 
  4224 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4225 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4226 are treated as atomic; subformulae not involving type `nat' or `int'
  4227 are ignored; quantified subformulae are ignored unless they are
  4228 positive universal or negative existential. The tactic has to be
  4229 invoked by hand and can be a little bit slow. In particular, the
  4230 running time is exponential in the number of occurrences of `min' and
  4231 `max', and `-' on `nat'.
  4232 
  4233 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4234 (negated) (in)equalities among the premises and the conclusion into
  4235 account (i.e. no compound formulae) and does not know about `min' and
  4236 `max', and `-' on `nat'. It is fast and is used automatically by the
  4237 simplifier.
  4238 
  4239 NB: At the moment, these decision procedures do not cope with mixed
  4240 nat/int formulae where the two parts interact, such as `m < n ==>
  4241 int(m) < int(n)'.
  4242 
  4243 * HOL/Numeral provides a generic theory of numerals (encoded
  4244 efficiently as bit strings); setup for types nat/int/real is in place;
  4245 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4246 int, existing theories and proof scripts may require a few additional
  4247 type constraints;
  4248 
  4249 * integer division and remainder can now be performed on constant
  4250 arguments;
  4251 
  4252 * many properties of integer multiplication, division and remainder
  4253 are now available;
  4254 
  4255 * An interface to the Stanford Validity Checker (SVC) is available through the
  4256 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4257 are proved automatically.  SVC must be installed separately, and its results
  4258 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4259 invocation of the underlying oracle).  For SVC see
  4260   http://verify.stanford.edu/SVC
  4261 
  4262 * IsaMakefile: the HOL-Real target now builds an actual image;
  4263 
  4264 
  4265 ** HOL misc **
  4266 
  4267 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4268 (in Isabelle/Isar) -- by Gertrud Bauer;
  4269 
  4270 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4271 analysis for assembly languages with subtypes;
  4272 
  4273 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4274 -- avoids syntactic ambiguities and treats state, transition, and
  4275 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4276 changed syntax and (many) tactics;
  4277 
  4278 * HOL/inductive: Now also handles more general introduction rules such
  4279   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4280   theorems are now maintained within the theory (maintained via the
  4281   "mono" attribute);
  4282 
  4283 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4284   (using function types) such as
  4285 
  4286   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4287 
  4288 * HOL/record: record_simproc (part of the default simpset) takes care
  4289 of selectors applied to updated records; record_split_tac is no longer
  4290 part of the default claset; update_defs may now be removed from the
  4291 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4292 
  4293   claset_ref () := claset() addSWrapper record_split_wrapper;
  4294   Delsimprocs [record_simproc]
  4295 
  4296 * HOL/typedef: fixed type inference for representing set; type
  4297 arguments now have to occur explicitly on the rhs as type constraints;
  4298 
  4299 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4300 names rather than an ML expression;
  4301 
  4302 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4303 supplied later.  Program schemes can be defined, such as
  4304     "While B C s = (if B s then While B C (C s) else s)"
  4305 where the well-founded relation can be chosen after B and C have been given.
  4306 
  4307 * HOL/List: the constructors of type list are now Nil and Cons;
  4308 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4309 course, ML tools referring to List.list.op # etc. have to be adapted;
  4310 
  4311 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4312 disabled by default; run isabelle with option -m HOL to get back to
  4313 the original Gordon/HOL-style output;
  4314 
  4315 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4316 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4317 
  4318 * HOL basic syntax simplified (more orthogonal): all variants of
  4319 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4320 Eps operator is provided as well: "SOME x. P[x]";
  4321 
  4322 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4323 
  4324 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4325 thus available for user theories;
  4326 
  4327 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4328 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4329 time;
  4330 
  4331 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4332 several times and then mp;
  4333 
  4334 
  4335 *** LK ***
  4336 
  4337 * the notation <<...>> is now available as a notation for sequences of
  4338 formulas;
  4339 
  4340 * the simplifier is now installed
  4341 
  4342 * the axiom system has been generalized (thanks to Soren Heilmann)
  4343 
  4344 * the classical reasoner now has a default rule database
  4345 
  4346 
  4347 *** ZF ***
  4348 
  4349 * new primrec section allows primitive recursive functions to be given
  4350 directly (as in HOL) over datatypes and the natural numbers;
  4351 
  4352 * new tactics induct_tac and exhaust_tac for induction (or case
  4353 analysis) over datatypes and the natural numbers;
  4354 
  4355 * the datatype declaration of type T now defines the recursor T_rec;
  4356 
  4357 * simplification automatically does freeness reasoning for datatype
  4358 constructors;
  4359 
  4360 * automatic type-inference, with AddTCs command to insert new
  4361 type-checking rules;
  4362 
  4363 * datatype introduction rules are now added as Safe Introduction rules
  4364 to the claset;
  4365 
  4366 * the syntax "if P then x else y" is now available in addition to
  4367 if(P,x,y);
  4368 
  4369 
  4370 *** Internal programming interfaces ***
  4371 
  4372 * tuned simplifier trace output; new flag debug_simp;
  4373 
  4374 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4375 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4376 
  4377 * AxClass.axclass_tac lost the theory argument;
  4378 
  4379 * tuned current_goals_markers semantics: begin / end goal avoids
  4380 printing empty lines;
  4381 
  4382 * removed prs and prs_fn hook, which was broken because it did not
  4383 include \n in its semantics, forcing writeln to add one
  4384 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4385 string -> unit if you really want to output text without newline;
  4386 
  4387 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4388 plain output, interface builders may have to enable 'isabelle_font'
  4389 mode to get Isabelle font glyphs as before;
  4390 
  4391 * refined token_translation interface; INCOMPATIBILITY: output length
  4392 now of type real instead of int;
  4393 
  4394 * theory loader actions may be traced via new ThyInfo.add_hook
  4395 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4396 your own database of information attached to *whole* theories -- as
  4397 opposed to intra-theory data slots offered via TheoryDataFun;
  4398 
  4399 * proper handling of dangling sort hypotheses (at last!);
  4400 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4401 extra sort hypotheses that can be witnessed from the type signature;
  4402 the force_strip_shyps flag is gone, any remaining shyps are simply
  4403 left in the theorem (with a warning issued by strip_shyps_warning);
  4404 
  4405 
  4406 
  4407 New in Isabelle98-1 (October 1998)
  4408 ----------------------------------
  4409 
  4410 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4411 
  4412 * several changes of automated proof tools;
  4413 
  4414 * HOL: major changes to the inductive and datatype packages, including
  4415 some minor incompatibilities of theory syntax;
  4416 
  4417 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4418 called `inj_on';
  4419 
  4420 * HOL: removed duplicate thms in Arith:
  4421   less_imp_add_less  should be replaced by  trans_less_add1
  4422   le_imp_add_le      should be replaced by  trans_le_add1
  4423 
  4424 * HOL: unary minus is now overloaded (new type constraints may be
  4425 required);
  4426 
  4427 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4428 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4429 now taken as an integer constant.
  4430 
  4431 * Pure: ML function 'theory_of' renamed to 'theory';
  4432 
  4433 
  4434 *** Proof tools ***
  4435 
  4436 * Simplifier:
  4437   1. Asm_full_simp_tac is now more aggressive.
  4438      1. It will sometimes reorient premises if that increases their power to
  4439         simplify.
  4440      2. It does no longer proceed strictly from left to right but may also
  4441         rotate premises to achieve further simplification.
  4442      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4443      old Asm_full_simp_tac in that it does not rotate premises.
  4444   2. The simplifier now knows a little bit about nat-arithmetic.
  4445 
  4446 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4447 allows for selected deletion of wrappers, by introduction of names for
  4448 wrapper functionals.  This implies that addbefore, addSbefore,
  4449 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4450 and that adding two tactics with the same name overwrites the first
  4451 one (emitting a warning).
  4452   type wrapper = (int -> tactic) -> (int -> tactic)
  4453   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4454   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4455   delWrapper, delSWrapper: claset *  string            -> claset
  4456   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4457 
  4458 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4459 semantics; addbefore now affects only the unsafe part of step_tac
  4460 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4461 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4462 by Force_tac;
  4463 
  4464 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4465 compWrapper; added safe wrapper (and access functions for it);
  4466 
  4467 * HOL/split_all_tac is now much faster and fails if there is nothing
  4468 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4469 and the names of the automatically generated variables have changed.
  4470 split_all_tac has moved within claset() from unsafe wrappers to safe
  4471 wrappers, which means that !!-bound variables are split much more
  4472 aggressively, and safe_tac and clarify_tac now split such variables.
  4473 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4474 Note: the same holds for record_split_tac, which does the job of
  4475 split_all_tac for record fields.
  4476 
  4477 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4478 permanently to the default simpset using Addsplits just like
  4479 Addsimps. They can be removed via Delsplits just like
  4480 Delsimps. Lower-case versions are also available.
  4481 
  4482 * HOL/Simplifier: The rule split_if is now part of the default
  4483 simpset. This means that the simplifier will eliminate all occurrences
  4484 of if-then-else in the conclusion of a goal. To prevent this, you can
  4485 either remove split_if completely from the default simpset by
  4486 `Delsplits [split_if]' or remove it in a specific call of the
  4487 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4488 other case splitting rules to/from the default simpset: every datatype
  4489 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4490 t is the name of the datatype).
  4491 
  4492 * Classical reasoner / Simplifier combination: new force_tac (and
  4493 derivatives Force_tac, force) combines rewriting and classical
  4494 reasoning (and whatever other tools) similarly to auto_tac, but is
  4495 aimed to solve the given subgoal completely.
  4496 
  4497 
  4498 *** General ***
  4499 
  4500 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4501 and `goalw': the theory is no longer needed as an explicit argument -
  4502 the current theory context is used; assumptions are no longer returned
  4503 at the ML-level unless one of them starts with ==> or !!; it is
  4504 recommended to convert to these new commands using isatool fixgoal
  4505 (backup your sources first!);
  4506 
  4507 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4508 the current theory context, and 'theory' to lookup stored theories;
  4509 
  4510 * new theory section 'locale' for declaring constants, assumptions and
  4511 definitions that have local scope;
  4512 
  4513 * new theory section 'nonterminals' for purely syntactic types;
  4514 
  4515 * new theory section 'setup' for generic ML setup functions
  4516 (e.g. package initialization);
  4517 
  4518 * the distribution now includes Isabelle icons: see
  4519 lib/logo/isabelle-{small,tiny}.xpm;
  4520 
  4521 * isatool install - install binaries with absolute references to
  4522 ISABELLE_HOME/bin;
  4523 
  4524 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4525 
  4526 * print mode 'emacs' reserved for Isamode;
  4527 
  4528 * support multiple print (ast) translations per constant name;
  4529 
  4530 * theorems involving oracles are now printed with a suffixed [!];
  4531 
  4532 
  4533 *** HOL ***
  4534 
  4535 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4536 
  4537 * HOL/inductive package reorganized and improved: now supports mutual
  4538 definitions such as
  4539 
  4540   inductive EVEN ODD
  4541     intrs
  4542       null "0 : EVEN"
  4543       oddI "n : EVEN ==> Suc n : ODD"
  4544       evenI "n : ODD ==> Suc n : EVEN"
  4545 
  4546 new theorem list "elims" contains an elimination rule for each of the
  4547 recursive sets; inductive definitions now handle disjunctive premises
  4548 correctly (also ZF);
  4549 
  4550 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4551 "mutual_induct" no longer exists - the induction rule is always
  4552 contained in "induct";
  4553 
  4554 
  4555 * HOL/datatype package re-implemented and greatly improved: now
  4556 supports mutually recursive datatypes such as
  4557 
  4558   datatype
  4559     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4560             | SUM ('a aexp) ('a aexp)
  4561             | DIFF ('a aexp) ('a aexp)
  4562             | NUM 'a
  4563   and
  4564     'a bexp = LESS ('a aexp) ('a aexp)
  4565             | AND ('a bexp) ('a bexp)
  4566             | OR ('a bexp) ('a bexp)
  4567 
  4568 as well as indirectly recursive datatypes such as
  4569 
  4570   datatype
  4571     ('a, 'b) term = Var 'a
  4572                   | App 'b ((('a, 'b) term) list)
  4573 
  4574 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4575 induction on mutually / indirectly recursive datatypes.
  4576 
  4577 Primrec equations are now stored in theory and can be accessed via
  4578 <function_name>.simps.
  4579 
  4580 INCOMPATIBILITIES:
  4581 
  4582   - Theories using datatypes must now have theory Datatype as an
  4583     ancestor.
  4584   - The specific <typename>.induct_tac no longer exists - use the
  4585     generic induct_tac instead.
  4586   - natE has been renamed to nat.exhaust - use exhaust_tac
  4587     instead of res_inst_tac ... natE. Note that the variable
  4588     names in nat.exhaust differ from the names in natE, this
  4589     may cause some "fragile" proofs to fail.
  4590   - The theorems split_<typename>_case and split_<typename>_case_asm
  4591     have been renamed to <typename>.split and <typename>.split_asm.
  4592   - Since default sorts of type variables are now handled correctly,
  4593     some datatype definitions may have to be annotated with explicit
  4594     sort constraints.
  4595   - Primrec definitions no longer require function name and type
  4596     of recursive argument.
  4597 
  4598 Consider using isatool fixdatatype to adapt your theories and proof
  4599 scripts to the new package (backup your sources first!).
  4600 
  4601 
  4602 * HOL/record package: considerably improved implementation; now
  4603 includes concrete syntax for record types, terms, updates; theorems
  4604 for surjective pairing and splitting !!-bound record variables; proof
  4605 support is as follows:
  4606 
  4607   1) standard conversions (selectors or updates applied to record
  4608 constructor terms) are part of the standard simpset;
  4609 
  4610   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4611 made part of standard simpset and claset via addIffs;
  4612 
  4613   3) a tactic for record field splitting (record_split_tac) is part of
  4614 the standard claset (addSWrapper);
  4615 
  4616 To get a better idea about these rules you may retrieve them via
  4617 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4618 the name of your record type.
  4619 
  4620 The split tactic 3) conceptually simplifies by the following rule:
  4621 
  4622   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4623 
  4624 Thus any record variable that is bound by meta-all will automatically
  4625 blow up into some record constructor term, consequently the
  4626 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4627 solve record problems automatically.
  4628 
  4629 
  4630 * reorganized the main HOL image: HOL/Integ and String loaded by
  4631 default; theory Main includes everything;
  4632 
  4633 * automatic simplification of integer sums and comparisons, using cancellation;
  4634 
  4635 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4636 
  4637 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4638 
  4639 * many new identities for unions, intersections, set difference, etc.;
  4640 
  4641 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4642 called split_if, split_split, split_sum_case and split_nat_case (to go
  4643 with add/delsplits);
  4644 
  4645 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4646 (?x::unit) = (); this is made part of the default simpset, which COULD
  4647 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4648 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4649 unit_abs_eta_conv is added in order to counter the effect of
  4650 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4651 %u.f();
  4652 
  4653 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4654 makes more sense);
  4655 
  4656 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4657   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4658   disjointness reasoning but breaking a few old proofs.
  4659 
  4660 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4661 to 'converse' from 'inverse' (for compatibility with ZF and some
  4662 literature);
  4663 
  4664 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4665 the well-founded relation;
  4666 
  4667 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4668     Compl A.  The "Compl" syntax remains available as input syntax for this
  4669     release ONLY.
  4670 
  4671 * HOL/Update: new theory of function updates:
  4672     f(a:=b) == %x. if x=a then b else f x
  4673 may also be iterated as in f(a:=b,c:=d,...);
  4674 
  4675 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4676 
  4677 * HOL/List:
  4678   - new function list_update written xs[i:=v] that updates the i-th
  4679     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4680   - new function `upt' written [i..j(] which generates the list
  4681     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4682     bound write [i..j], which is a shorthand for [i..j+1(].
  4683   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4684 
  4685 * HOL/Arith:
  4686   - removed 'pred' (predecessor) function;
  4687   - generalized some theorems about n-1;
  4688   - many new laws about "div" and "mod";
  4689   - new laws about greatest common divisors (see theory ex/Primes);
  4690 
  4691 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4692 instead of "inverse";
  4693 
  4694 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4695   of the multiset ordering;
  4696 
  4697 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4698   (not included by default);
  4699 
  4700 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4701 
  4702 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4703   programs, i.e. different program variables may have different types.
  4704 
  4705 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4706   [previously, this check worked only if the rewrite rule was unconditional]
  4707   Now rew can involve either definitions or equalities (either == or =).
  4708 
  4709 
  4710 *** ZF ***
  4711 
  4712 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4713   only the theorems proved on ZF.ML;
  4714 
  4715 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4716   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4717   disjointness reasoning but breaking a few old proofs.
  4718 
  4719 * ZF/Update: new theory of function updates
  4720     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4721   may also be iterated as in f(a:=b,c:=d,...);
  4722 
  4723 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4724 
  4725 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4726   [previously, this check worked only if the rewrite rule was unconditional]
  4727   Now rew can involve either definitions or equalities (either == or =).
  4728 
  4729 * case_tac provided for compatibility with HOL
  4730     (like the old excluded_middle_tac, but with subgoals swapped)
  4731 
  4732 
  4733 *** Internal programming interfaces ***
  4734 
  4735 * Pure: several new basic modules made available for general use, see
  4736 also src/Pure/README;
  4737 
  4738 * improved the theory data mechanism to support encapsulation (data
  4739 kind name replaced by private Object.kind, acting as authorization
  4740 key); new type-safe user interface via functor TheoryDataFun; generic
  4741 print_data function becomes basically useless;
  4742 
  4743 * removed global_names compatibility flag -- all theory declarations
  4744 are qualified by default;
  4745 
  4746 * module Pure/Syntax now offers quote / antiquote translation
  4747 functions (useful for Hoare logic etc. with implicit dependencies);
  4748 see HOL/ex/Antiquote for an example use;
  4749 
  4750 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4751 cterm -> thm;
  4752 
  4753 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4754 subgoal;
  4755 
  4756 * Display.print_goals function moved to Locale.print_goals;
  4757 
  4758 * standard print function for goals supports current_goals_markers
  4759 variable for marking begin of proof, end of proof, start of goal; the
  4760 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4761 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4762 for example;
  4763 
  4764 
  4765 
  4766 New in Isabelle98 (January 1998)
  4767 --------------------------------
  4768 
  4769 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4770 
  4771 * changed lexical syntax of terms / types: dots made part of long
  4772 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4773 
  4774 * simpset (and claset) reference variable replaced by functions
  4775 simpset / simpset_ref;
  4776 
  4777 * no longer supports theory aliases (via merge) and non-trivial
  4778 implicit merge of thms' signatures;
  4779 
  4780 * most internal names of constants changed due to qualified names;
  4781 
  4782 * changed Pure/Sequence interface (see Pure/seq.ML);
  4783 
  4784 
  4785 *** General Changes ***
  4786 
  4787 * hierachically structured name spaces (for consts, types, axms, thms
  4788 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4789 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4790 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4791 long_names for fully qualified output names; NOTE: ML programs
  4792 (special tactics, packages etc.) referring to internal names may have
  4793 to be adapted to cope with fully qualified names; in case of severe
  4794 backward campatibility problems try setting 'global_names' at compile
  4795 time to have enrything declared within a flat name space; one may also
  4796 fine tune name declarations in theories via the 'global' and 'local'
  4797 section;
  4798 
  4799 * reimplemented the implicit simpset and claset using the new anytype
  4800 data filed in signatures; references simpset:simpset ref etc. are
  4801 replaced by functions simpset:unit->simpset and
  4802 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4803 to patch your ML files accordingly;
  4804 
  4805 * HTML output now includes theory graph data for display with Java
  4806 applet or isatool browser; data generated automatically via isatool
  4807 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4808 
  4809 * defs may now be conditional; improved rewrite_goals_tac to handle
  4810 conditional equations;
  4811 
  4812 * defs now admits additional type arguments, using TYPE('a) syntax;
  4813 
  4814 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4815 creates a new theory node; implicit merge of thms' signatures is
  4816 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4817 transfer:theory->thm->thm in (rare) cases;
  4818 
  4819 * improved handling of draft signatures / theories; draft thms (and
  4820 ctyps, cterms) are automatically promoted to real ones;
  4821 
  4822 * slightly changed interfaces for oracles: admit many per theory, named
  4823 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4824 
  4825 * print_goals: optional output of const types (set show_consts and
  4826 show_types);
  4827 
  4828 * improved output of warnings (###) and errors (***);
  4829 
  4830 * subgoal_tac displays a warning if the new subgoal has type variables;
  4831 
  4832 * removed old README and Makefiles;
  4833 
  4834 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4835 
  4836 * removed obsolete init_pps and init_database;
  4837 
  4838 * deleted the obsolete tactical STATE, which was declared by
  4839     fun STATE tacfun st = tacfun st st;
  4840 
  4841 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4842 (which abbreviates $HOME);
  4843 
  4844 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4845 use isatool fixseq to adapt your ML programs (this works for fully
  4846 qualified references to the Sequence structure only!);
  4847 
  4848 * use_thy no longer requires writable current directory; it always
  4849 reloads .ML *and* .thy file, if either one is out of date;
  4850 
  4851 
  4852 *** Classical Reasoner ***
  4853 
  4854 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4855 tactics that use classical reasoning to simplify a subgoal without
  4856 splitting it into several subgoals;
  4857 
  4858 * Safe_tac: like safe_tac but uses the default claset;
  4859 
  4860 
  4861 *** Simplifier ***
  4862 
  4863 * added simplification meta rules:
  4864     (asm_)(full_)simplify: simpset -> thm -> thm;
  4865 
  4866 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4867 logics (again);
  4868 
  4869 * added prems argument to simplification procedures;
  4870 
  4871 * HOL, FOL, ZF: added infix function `addsplits':
  4872   instead of `<simpset> setloop (split_tac <thms>)'
  4873   you can simply write `<simpset> addsplits <thms>'
  4874 
  4875 
  4876 *** Syntax ***
  4877 
  4878 * TYPE('a) syntax for type reflection terms;
  4879 
  4880 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4881 
  4882 * pretty printer: changed order of mixfix annotation preference (again!);
  4883 
  4884 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4885 
  4886 
  4887 *** HOL ***
  4888 
  4889 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4890   with `addloop' of the simplifier to faciliate case splitting in premises.
  4891 
  4892 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4893 
  4894 * HOL/Auth: new protocol proofs including some for the Internet
  4895   protocol TLS;
  4896 
  4897 * HOL/Map: new theory of `maps' a la VDM;
  4898 
  4899 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4900 cancelling out common nat summands from =, <, <= (in)equalities, or
  4901 differences; simplification procedures nat_cancel_factor for
  4902 cancelling common factor from =, <, <= (in)equalities over natural
  4903 sums; nat_cancel contains both kinds of procedures, it is installed by
  4904 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4905 
  4906 * HOL/simplifier: terms of the form
  4907   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4908   are rewritten to
  4909   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4910   and those of the form
  4911   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4912   are rewritten to
  4913   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4914 
  4915 * HOL/datatype
  4916   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4917 
  4918   P(t_case f1 ... fn x) =
  4919      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4920         ...
  4921        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4922      )
  4923 
  4924   and a theorem `split_t_case_asm' of the form
  4925 
  4926   P(t_case f1 ... fn x) =
  4927     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4928         ...
  4929        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4930      )
  4931   which can be added to a simpset via `addsplits'. The existing theorems
  4932   expand_list_case and expand_option_case have been renamed to
  4933   split_list_case and split_option_case.
  4934 
  4935 * HOL/Arithmetic:
  4936   - `pred n' is automatically converted to `n-1'.
  4937     Users are strongly encouraged not to use `pred' any longer,
  4938     because it will disappear altogether at some point.
  4939   - Users are strongly encouraged to write "0 < n" rather than
  4940     "n ~= 0". Theorems and proof tools have been modified towards this
  4941     `standard'.
  4942 
  4943 * HOL/Lists:
  4944   the function "set_of_list" has been renamed "set" (and its theorems too);
  4945   the function "nth" now takes its arguments in the reverse order and
  4946   has acquired the infix notation "!" as in "xs!n".
  4947 
  4948 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4949 
  4950 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4951   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4952 
  4953 * HOL/record: extensible records with schematic structural subtyping
  4954 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4955 still lacks various theorems and concrete record syntax;
  4956 
  4957 
  4958 *** HOLCF ***
  4959 
  4960 * removed "axioms" and "generated by" sections;
  4961 
  4962 * replaced "ops" section by extended "consts" section, which is capable of
  4963   handling the continuous function space "->" directly;
  4964 
  4965 * domain package:
  4966   . proves theorems immediately and stores them in the theory,
  4967   . creates hierachical name space,
  4968   . now uses normal mixfix annotations (instead of cinfix...),
  4969   . minor changes to some names and values (for consistency),
  4970   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4971   . separator between mutual domain defs: changed "," to "and",
  4972   . improved handling of sort constraints;  now they have to
  4973     appear on the left-hand side of the equations only;
  4974 
  4975 * fixed LAM <x,y,zs>.b syntax;
  4976 
  4977 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4978 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4979 
  4980 
  4981 *** FOL and ZF ***
  4982 
  4983 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4984   with `addloop' of the simplifier to faciliate case splitting in premises.
  4985 
  4986 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4987 in HOL, they strip ALL and --> from proved theorems;
  4988 
  4989 
  4990 
  4991 New in Isabelle94-8 (May 1997)
  4992 ------------------------------
  4993 
  4994 *** General Changes ***
  4995 
  4996 * new utilities to build / run / maintain Isabelle etc. (in parts
  4997 still somewhat experimental); old Makefiles etc. still functional;
  4998 
  4999 * new 'Isabelle System Manual';
  5000 
  5001 * INSTALL text, together with ./configure and ./build scripts;
  5002 
  5003 * reimplemented type inference for greater efficiency, better error
  5004 messages and clean internal interface;
  5005 
  5006 * prlim command for dealing with lots of subgoals (an easier way of
  5007 setting goals_limit);
  5008 
  5009 
  5010 *** Syntax ***
  5011 
  5012 * supports alternative (named) syntax tables (parser and pretty
  5013 printer); internal interface is provided by add_modesyntax(_i);
  5014 
  5015 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5016 be used in conjunction with the Isabelle symbol font; uses the
  5017 "symbols" syntax table;
  5018 
  5019 * added token_translation interface (may translate name tokens in
  5020 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5021 the current print_mode); IMPORTANT: user print translation functions
  5022 are responsible for marking newly introduced bounds
  5023 (Syntax.mark_boundT);
  5024 
  5025 * token translations for modes "xterm" and "xterm_color" that display
  5026 names in bold, underline etc. or colors (which requires a color
  5027 version of xterm);
  5028 
  5029 * infixes may now be declared with names independent of their syntax;
  5030 
  5031 * added typed_print_translation (like print_translation, but may
  5032 access type of constant);
  5033 
  5034 
  5035 *** Classical Reasoner ***
  5036 
  5037 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5038 some limitations.  Blast_tac...
  5039   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5040   + ignores elimination rules that don't have the correct format
  5041         (the conclusion MUST be a formula variable)
  5042   + ignores types, which can make HOL proofs fail
  5043   + rules must not require higher-order unification, e.g. apply_type in ZF
  5044     [message "Function Var's argument not a bound variable" relates to this]
  5045   + its proof strategy is more general but can actually be slower
  5046 
  5047 * substitution with equality assumptions no longer permutes other
  5048 assumptions;
  5049 
  5050 * minor changes in semantics of addafter (now called addaltern); renamed
  5051 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5052 (and access functions for it);
  5053 
  5054 * improved combination of classical reasoner and simplifier:
  5055   + functions for handling clasimpsets
  5056   + improvement of addss: now the simplifier is called _after_ the
  5057     safe steps.
  5058   + safe variant of addss called addSss: uses safe simplifications
  5059     _during_ the safe steps. It is more complete as it allows multiple
  5060     instantiations of unknowns (e.g. with slow_tac).
  5061 
  5062 *** Simplifier ***
  5063 
  5064 * added interface for simplification procedures (functions that
  5065 produce *proven* rewrite rules on the fly, depending on current
  5066 redex);
  5067 
  5068 * ordering on terms as parameter (used for ordered rewriting);
  5069 
  5070 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5071 
  5072 * the solver is now split into a safe and an unsafe part.
  5073 This should be invisible for the normal user, except that the
  5074 functions setsolver and addsolver have been renamed to setSolver and
  5075 addSolver; added safe_asm_full_simp_tac;
  5076 
  5077 
  5078 *** HOL ***
  5079 
  5080 * a generic induction tactic `induct_tac' which works for all datatypes and
  5081 also for type `nat';
  5082 
  5083 * a generic case distinction tactic `exhaust_tac' which works for all
  5084 datatypes and also for type `nat';
  5085 
  5086 * each datatype comes with a function `size';
  5087 
  5088 * patterns in case expressions allow tuple patterns as arguments to
  5089 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5090 
  5091 * primrec now also works with type nat;
  5092 
  5093 * recdef: a new declaration form, allows general recursive functions to be
  5094 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5095 
  5096 * the constant for negation has been renamed from "not" to "Not" to
  5097 harmonize with FOL, ZF, LK, etc.;
  5098 
  5099 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5100 infinite lists;
  5101 
  5102 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5103 
  5104 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5105 problems in commutative rings, using axiomatic type classes for + and *;
  5106 
  5107 * more examples in HOL/MiniML and HOL/Auth;
  5108 
  5109 * more default rewrite rules for quantifiers, union/intersection;
  5110 
  5111 * a new constant `arbitrary == @x.False';
  5112 
  5113 * HOLCF/IOA replaces old HOL/IOA;
  5114 
  5115 * HOLCF changes: derived all rules and arities
  5116   + axiomatic type classes instead of classes
  5117   + typedef instead of faking type definitions
  5118   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5119   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5120   + eliminated the types void, one, tr
  5121   + use unit lift and bool lift (with translations) instead of one and tr
  5122   + eliminated blift from Lift3.thy (use Def instead of blift)
  5123   all eliminated rules are derived as theorems --> no visible changes ;
  5124 
  5125 
  5126 *** ZF ***
  5127 
  5128 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5129 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5130 as ZF_cs addSIs [equalityI];
  5131 
  5132 
  5133 
  5134 New in Isabelle94-7 (November 96)
  5135 ---------------------------------
  5136 
  5137 * allowing negative levels (as offsets) in prlev and choplev;
  5138 
  5139 * super-linear speedup for large simplifications;
  5140 
  5141 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5142 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5143 FAIL); can suppress it using the command Delsimps (ex_simps @
  5144 all_simps); De Morgan laws are also now included, by default;
  5145 
  5146 * improved printing of ==>  :  ~:
  5147 
  5148 * new object-logic "Sequents" adds linear logic, while replacing LK
  5149 and Modal (thanks to Sara Kalvala);
  5150 
  5151 * HOL/Auth: correctness proofs for authentication protocols;
  5152 
  5153 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5154 examples on HOL/Auth);
  5155 
  5156 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5157 the rewriter and classical reasoner simultaneously;
  5158 
  5159 * function uresult no longer returns theorems in "standard" format;
  5160 regain previous version by: val uresult = standard o uresult;
  5161 
  5162 
  5163 
  5164 New in Isabelle94-6
  5165 -------------------
  5166 
  5167 * oracles -- these establish an interface between Isabelle and trusted
  5168 external reasoners, which may deliver results as theorems;
  5169 
  5170 * proof objects (in particular record all uses of oracles);
  5171 
  5172 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5173 
  5174 * "constdefs" section in theory files;
  5175 
  5176 * "primrec" section (HOL) no longer requires names;
  5177 
  5178 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5179 
  5180 
  5181 
  5182 New in Isabelle94-5
  5183 -------------------
  5184 
  5185 * reduced space requirements;
  5186 
  5187 * automatic HTML generation from theories;
  5188 
  5189 * theory files no longer require "..." (quotes) around most types;
  5190 
  5191 * new examples, including two proofs of the Church-Rosser theorem;
  5192 
  5193 * non-curried (1994) version of HOL is no longer distributed;
  5194 
  5195 
  5196 
  5197 New in Isabelle94-4
  5198 -------------------
  5199 
  5200 * greatly reduced space requirements;
  5201 
  5202 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5203 
  5204 * searchable theorem database (see the section "Retrieving theorems" on
  5205 page 8 of the Reference Manual);
  5206 
  5207 * new examples, including Grabczewski's monumental case study of the
  5208 Axiom of Choice;
  5209 
  5210 * The previous version of HOL renamed to Old_HOL;
  5211 
  5212 * The new version of HOL (previously called CHOL) uses a curried syntax
  5213 for functions.  Application looks like f a b instead of f(a,b);
  5214 
  5215 * Mutually recursive inductive definitions finally work in HOL;
  5216 
  5217 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5218 translates to the operator "split";
  5219 
  5220 
  5221 
  5222 New in Isabelle94-3
  5223 -------------------
  5224 
  5225 * new infix operator, addss, allowing the classical reasoner to
  5226 perform simplification at each step of its search.  Example:
  5227         fast_tac (cs addss ss)
  5228 
  5229 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5230 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5231 look like (a,b) instead of <a,b>;
  5232 
  5233 * PLEASE NOTE: CHOL will eventually replace HOL!
  5234 
  5235 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5236 It translates to the operator "split".  A new theory of integers is available;
  5237 
  5238 * In ZF, integer numerals now denote two's-complement binary integers.
  5239 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5240 
  5241 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5242 of the Axiom of Choice;
  5243 
  5244 
  5245 
  5246 New in Isabelle94-2
  5247 -------------------
  5248 
  5249 * Significantly faster resolution;
  5250 
  5251 * the different sections in a .thy file can now be mixed and repeated
  5252 freely;
  5253 
  5254 * Database of theorems for FOL, HOL and ZF.  New
  5255 commands including qed, qed_goal and bind_thm store theorems in the database.
  5256 
  5257 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5258 a given theory (thms_of), or find out what theory a theorem was proved in
  5259 (theory_of_thm);
  5260 
  5261 * Bugs fixed in the inductive definition and datatype packages;
  5262 
  5263 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5264 and HOL_dup_cs obsolete;
  5265 
  5266 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5267 have been removed;
  5268 
  5269 * Simpler definition of function space in ZF;
  5270 
  5271 * new results about cardinal and ordinal arithmetic in ZF;
  5272 
  5273 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5274 types;
  5275 
  5276 :mode=text:wrap=hard:maxLineLen=72:
  5277 
  5278 $Id$