NEWS
author nipkow
Sun Mar 02 15:02:06 2008 +0100 (2008-03-02)
changeset 26191 ae537f315b34
parent 26188 9cb1b484fe96
child 26197 46e63f49c946
permissions -rw-r--r--
Generalized Zorn and added well-ordering theorem
     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 
    26 *** Pure ***
    27 
    28 * Instantiation target allows for simultaneous specification of class
    29 instance operations together with an instantiation proof.
    30 Type-checking phase allows to refer to class operations uniformly.
    31 See HOL/Complex/Complex.thy for an Isar example and
    32 HOL/Library/Eval.thy for an ML example.
    33 
    34 
    35 *** HOL ***
    36 
    37 * Theory Int: The representation of numerals has changed.  The infix
    38 operator BIT and the bit datatype with constructors B0 and B1 have
    39 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
    40 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
    41 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
    42 accordingly.
    43 
    44 * Theory Nat: definition of <= and < on natural numbers no longer
    45 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
    46 le_def and less_def have disappeared.  Consider lemmas not_less
    47 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
    48 
    49 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
    50 (whose purpose mainly is for various fold_set functionals) have been
    51 abandoned in favour of the existing algebraic classes
    52 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
    53 lower_semilattice (resp. upper_semilattice) and linorder.
    54 INCOMPATIBILITY.
    55 
    56 * Theory Transitive_Closure: induct and cases rules now declare proper
    57 case_names ("base" and "step").  INCOMPATIBILITY.
    58 
    59 * Theorem Inductive.lfp_ordinal_induct generalized to complete
    60 lattices.  The form set-specific version is available as
    61 Inductive.lfp_ordinal_induct_set.
    62 
    63 * Theorems "power.simps" renamed to "power_int.simps".
    64 
    65 * Class semiring_div provides basic abstract properties of semirings
    66 with division and modulo operations.  Subsumes former class dvd_mod.
    67 
    68 * Merged theories IntDef, Numeral and IntArith into unified theory
    69 Int.  INCOMPATIBILITY.
    70 
    71 * Theory Library/Code_Index: type "index" now represents natural
    72 numbers rather than integers.  INCOMPATIBILITY.
    73 
    74 * New class "uminus" with operation "uminus" (split of from class
    75 "minus" which now only has operation "minus", binary).
    76 INCOMPATIBILITY.
    77 
    78 * New primrec package.  Specification syntax conforms in style to
    79 definition/function/....  No separate induction rule is provided.  The
    80 "primrec" command distinguishes old-style and new-style specifications
    81 by syntax.  The former primrec package is now named OldPrimrecPackage.
    82 When adjusting theories, beware: constants stemming for new-style
    83 primrec specifications have authentic syntax.
    84 
    85 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
    86 
    87 * Library/ListVector: new theory of arithmetic vector operations.
    88 
    89 * Constants "card", "internal_split", "option_map" now with authentic
    90 syntax.  INCOMPATIBILITY.
    91 
    92 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
    93 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
    94 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
    95 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
    96 Sup_set_def, le_def, less_def, option_map_def now with object
    97 equality.  INCOMPATIBILITY.
    98 
    99 * Method "induction_scheme" derives user-specified induction rules
   100 from wellfounded induction and completeness of patterns. This factors
   101 out some operations that are done internally by the function package
   102 and makes them available separately. See "HOL/ex/Induction_Scheme.thy"
   103 for examples,
   104 
   105 * Records. Removed K_record, and replaced it by pure lambda term
   106 %x. c. The simplifier setup is now more robust against eta expansion.
   107 INCOMPATIBILITY: in cases explicitly referring to K_record.
   108 
   109 * Metis prover is now an order of magnitude faster, and also works
   110 with multithreading.
   111 
   112 
   113 *** ML ***
   114 
   115 * ML within Isar: antiquotation @{const name} or @{const
   116 name(typargs)} produces statically-checked Const term.
   117 
   118 * The ``print mode'' is now a thread-local value derived from a global
   119 template (the former print_mode reference), thus access becomes
   120 non-critical.  The global print_mode reference is for session
   121 management only; user-code should use print_mode_value,
   122 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
   123 
   124 
   125 *** System ***
   126 
   127 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
   128 in accordance with Proof General 3.7, which prefers GNU emacs.
   129 
   130 * Multithreading.max_threads := 0 refers to the number of actual CPU
   131 cores of the underlying machine, which is a good starting point for
   132 optimal performance tuning.  The corresponding usedir option -M allows
   133 "max" as an alias for "0".  WARNING: does not work on certain versions
   134 of Mac OS (with Poly/ML 5.1).
   135 
   136 * isatool tty runs Isabelle process with plain tty interaction;
   137 optional line editor may be specified via ISABELLE_LINE_EDITOR
   138 setting, the default settings attempt to locate "ledit" and "rlwrap".
   139 
   140 * isatool browser now works with Cygwin as well, using general
   141 "javapath" function defined in Isabelle process environment.
   142 
   143 * isabelle-process: non-ML sessions are run with "nice", to prevent
   144 Isabelle from flooding interactive front-ends (notably ProofGeneral /
   145 XEmacs).
   146 
   147 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   148 provides general wrapper for managing an Isabelle process in a robust
   149 fashion, with ``cooked'' output from stdin/stderr.
   150 
   151 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   152 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   153 
   154 
   155 
   156 New in Isabelle2007 (November 2007)
   157 -----------------------------------
   158 
   159 *** General ***
   160 
   161 * More uniform information about legacy features, notably a
   162 warning/error of "Legacy feature: ...", depending on the state of the
   163 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   164 legacy features will disappear eventually.
   165 
   166 * Theory syntax: the header format ``theory A = B + C:'' has been
   167 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   168 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   169 
   170 * Theory syntax: the old non-Isar theory file format has been
   171 discontinued altogether.  Note that ML proof scripts may still be used
   172 with Isar theories; migration is usually quite simple with the ML
   173 function use_legacy_bindings.  INCOMPATIBILITY.
   174 
   175 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   176 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   177 quotes.
   178 
   179 * Theory loader: be more serious about observing the static theory
   180 header specifications (including optional directories), but not the
   181 accidental file locations of previously successful loads.  The strict
   182 update policy of former update_thy is now already performed by
   183 use_thy, so the former has been removed; use_thys updates several
   184 theories simultaneously, just as 'imports' within a theory header
   185 specification, but without merging the results.  Potential
   186 INCOMPATIBILITY: may need to refine theory headers and commands
   187 ROOT.ML which depend on load order.
   188 
   189 * Theory loader: optional support for content-based file
   190 identification, instead of the traditional scheme of full physical
   191 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   192 (cf. the system manual).  The new scheme allows to work with
   193 non-finished theories in persistent session images, such that source
   194 files may be moved later on without requiring reloads.
   195 
   196 * Theory loader: old-style ML proof scripts being *attached* to a thy
   197 file (with the same base name as the theory) are considered a legacy
   198 feature, which will disappear eventually. Even now, the theory loader
   199 no longer maintains dependencies on such files.
   200 
   201 * Syntax: the scope for resolving ambiguities via type-inference is
   202 now limited to individual terms, instead of whole simultaneous
   203 specifications as before. This greatly reduces the complexity of the
   204 syntax module and improves flexibility by separating parsing and
   205 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
   206 'fixes' etc.) are required in rare situations.
   207 
   208 * Syntax: constants introduced by new-style packages ('definition',
   209 'abbreviation' etc.) are passed through the syntax module in
   210 ``authentic mode''. This means that associated mixfix annotations
   211 really stick to such constants, independently of potential name space
   212 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
   213 trees are represented slightly differently, may need to adapt syntax
   214 translations accordingly. Use CONST marker in 'translations' and
   215 @{const_syntax} antiquotation in 'parse_translation' etc.
   216 
   217 * Legacy goal package: reduced interface to the bare minimum required
   218 to keep existing proof scripts running.  Most other user-level
   219 functions are now part of the OldGoals structure, which is *not* open
   220 by default (consider isatool expandshort before open OldGoals).
   221 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   222 these tend to cause confusion about the actual goal (!) context being
   223 used here, which is not necessarily the same as the_context().
   224 
   225 * Command 'find_theorems': supports "*" wild-card in "name:"
   226 criterion; "with_dups" option.  Certain ProofGeneral versions might
   227 support a specific search form (see ProofGeneral/CHANGES).
   228 
   229 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   230 by default, which means that "prems" (and also "fixed variables") are
   231 suppressed from proof state output.  Note that the ProofGeneral
   232 settings mechanism allows to change and save options persistently, but
   233 older versions of Isabelle will fail to start up if a negative prems
   234 limit is imposed.
   235 
   236 * Local theory targets may be specified by non-nested blocks of
   237 ``context/locale/class ... begin'' followed by ``end''.  The body may
   238 contain definitions, theorems etc., including any derived mechanism
   239 that has been implemented on top of these primitives.  This concept
   240 generalizes the existing ``theorem (in ...)'' towards more versatility
   241 and scalability.
   242 
   243 * Proof General interface: proper undo of final 'end' command;
   244 discontinued Isabelle/classic mode (ML proof scripts).
   245 
   246 
   247 *** Document preparation ***
   248 
   249 * Added antiquotation @{theory name} which prints the given name,
   250 after checking that it refers to a valid ancestor theory in the
   251 current context.
   252 
   253 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   254 check the given source text as ML type/structure, printing verbatim.
   255 
   256 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   257 "c args == rhs" given in the current context.  (Any number of
   258 arguments may be given on the LHS.)
   259 
   260 
   261 *** Pure ***
   262 
   263 * The 'class' package offers a combination of axclass and locale to
   264 achieve Haskell-like type classes in Isabelle.  Definitions and
   265 theorems within a class context produce both relative results (with
   266 implicit parameters according to the locale context), and polymorphic
   267 constants with qualified polymorphism (according to the class
   268 context).  Within the body context of a 'class' target, a separate
   269 syntax layer ("user space type system") takes care of converting
   270 between global polymorphic consts and internal locale representation.
   271 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   272 "isatool doc classes" provides a tutorial.
   273 
   274 * Generic code generator framework allows to generate executable
   275 code for ML and Haskell (including Isabelle classes).  A short usage
   276 sketch:
   277 
   278     internal compilation:
   279         export_code <list of constants (term syntax)> in SML
   280     writing SML code to a file:
   281         export_code <list of constants (term syntax)> in SML <filename>
   282     writing OCaml code to a file:
   283         export_code <list of constants (term syntax)> in OCaml <filename>
   284     writing Haskell code to a bunch of files:
   285         export_code <list of constants (term syntax)> in Haskell <filename>
   286 
   287     evaluating closed propositions to True/False using code generation:
   288         method ``eval''
   289 
   290 Reasonable default setup of framework in HOL.
   291 
   292 Theorem attributs for selecting and transforming function equations theorems:
   293 
   294     [code fun]:        select a theorem as function equation for a specific constant
   295     [code fun del]:    deselect a theorem as function equation for a specific constant
   296     [code inline]:     select an equation theorem for unfolding (inlining) in place
   297     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   298 
   299 User-defined serializations (target in {SML, OCaml, Haskell}):
   300 
   301     code_const <and-list of constants (term syntax)>
   302       {(target) <and-list of const target syntax>}+
   303 
   304     code_type <and-list of type constructors>
   305       {(target) <and-list of type target syntax>}+
   306 
   307     code_instance <and-list of instances>
   308       {(target)}+
   309         where instance ::= <type constructor> :: <class>
   310 
   311     code_class <and_list of classes>
   312       {(target) <and-list of class target syntax>}+
   313         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   314 
   315 code_instance and code_class only are effective to target Haskell.
   316 
   317 For example usage see src/HOL/ex/Codegenerator.thy and
   318 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   319 generation from Isabelle/HOL theories is available via "isatool doc
   320 codegen".
   321 
   322 * Code generator: consts in 'consts_code' Isar commands are now
   323 referred to by usual term syntax (including optional type
   324 annotations).
   325 
   326 * Command 'no_translations' removes translation rules from theory
   327 syntax.
   328 
   329 * Overloaded definitions are now actually checked for acyclic
   330 dependencies.  The overloading scheme is slightly more general than
   331 that of Haskell98, although Isabelle does not demand an exact
   332 correspondence to type class and instance declarations.
   333 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   334 exotic versions of overloading -- at the discretion of the user!
   335 
   336 Polymorphic constants are represented via type arguments, i.e. the
   337 instantiation that matches an instance against the most general
   338 declaration given in the signature.  For example, with the declaration
   339 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   340 as c(nat).  Overloading is essentially simultaneous structural
   341 recursion over such type arguments.  Incomplete specification patterns
   342 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   343 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   344 Command 'print_theory' outputs the normalized system of recursive
   345 equations, see section "definitions".
   346 
   347 * Configuration options are maintained within the theory or proof
   348 context (with name and type bool/int/string), providing a very simple
   349 interface to a poor-man's version of general context data.  Tools may
   350 declare options in ML (e.g. using Attrib.config_int) and then refer to
   351 these values using Config.get etc.  Users may change options via an
   352 associated attribute of the same name.  This form of context
   353 declaration works particularly well with commands 'declare' or
   354 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   355 very easy to avoid global references, which would not observe Isar
   356 toplevel undo/redo and fail to work with multithreading.
   357 
   358 Various global ML references of Pure and HOL have been turned into
   359 configuration options:
   360 
   361   Unify.search_bound		unify_search_bound
   362   Unify.trace_bound		unify_trace_bound
   363   Unify.trace_simp		unify_trace_simp
   364   Unify.trace_types		unify_trace_types
   365   Simplifier.simp_depth_limit	simp_depth_limit
   366   Blast.depth_limit		blast_depth_limit
   367   DatatypeProp.dtK		datatype_distinctness_limit
   368   fast_arith_neq_limit  	fast_arith_neq_limit
   369   fast_arith_split_limit	fast_arith_split_limit
   370 
   371 * Named collections of theorems may be easily installed as context
   372 data using the functor NamedThmsFun (see also
   373 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   374 attributes; there is also a toplevel print command.  This facility is
   375 just a common case of general context data, which is the preferred way
   376 for anything more complex than just a list of facts in canonical
   377 order.
   378 
   379 * Isar: command 'declaration' augments a local theory by generic
   380 declaration functions written in ML.  This enables arbitrary content
   381 being added to the context, depending on a morphism that tells the
   382 difference of the original declaration context wrt. the application
   383 context encountered later on.
   384 
   385 * Isar: proper interfaces for simplification procedures.  Command
   386 'simproc_setup' declares named simprocs (with match patterns, and body
   387 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   388 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   389 
   390 * Isar: an extra pair of brackets around attribute declarations
   391 abbreviates a theorem reference involving an internal dummy fact,
   392 which will be ignored later --- only the effect of the attribute on
   393 the background context will persist.  This form of in-place
   394 declarations is particularly useful with commands like 'declare' and
   395 'using', for example ``have A using [[simproc a]] by simp''.
   396 
   397 * Isar: method "assumption" (and implicit closing of subproofs) now
   398 takes simple non-atomic goal assumptions into account: after applying
   399 an assumption as a rule the resulting subgoals are solved by atomic
   400 assumption steps.  This is particularly useful to finish 'obtain'
   401 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   402 without referring to the original premise "!!x. P x ==> thesis" in the
   403 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   404 more permissive.
   405 
   406 * Isar: implicit use of prems from the Isar proof context is
   407 considered a legacy feature.  Common applications like ``have A .''
   408 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   409 referencing facts explicitly here improves readability and
   410 maintainability of proof texts.
   411 
   412 * Isar: improper proof element 'guess' is like 'obtain', but derives
   413 the obtained context from the course of reasoning!  For example:
   414 
   415   assume "EX x y. A x & B y"   -- "any previous fact"
   416   then guess x and y by clarify
   417 
   418 This technique is potentially adventurous, depending on the facts and
   419 proof tools being involved here.
   420 
   421 * Isar: known facts from the proof context may be specified as literal
   422 propositions, using ASCII back-quote syntax.  This works wherever
   423 named facts used to be allowed so far, in proof commands, proof
   424 methods, attributes etc.  Literal facts are retrieved from the context
   425 according to unification of type and term parameters.  For example,
   426 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   427 theorems in the current context, then these are valid literal facts:
   428 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   429 
   430 There is also a proof method "fact" which does the same composition
   431 for explicit goal states, e.g. the following proof texts coincide with
   432 certain special cases of literal facts:
   433 
   434   have "A" by fact                 ==  note `A`
   435   have "A ==> B" by fact           ==  note `A ==> B`
   436   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   437   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   438 
   439 * Isar: ":" (colon) is no longer a symbolic identifier character in
   440 outer syntax.  Thus symbolic identifiers may be used without
   441 additional white space in declarations like this: ``assume *: A''.
   442 
   443 * Isar: 'print_facts' prints all local facts of the current context,
   444 both named and unnamed ones.
   445 
   446 * Isar: 'def' now admits simultaneous definitions, e.g.:
   447 
   448   def x == "t" and y == "u"
   449 
   450 * Isar: added command 'unfolding', which is structurally similar to
   451 'using', but affects both the goal state and facts by unfolding given
   452 rewrite rules.  Thus many occurrences of the 'unfold' method or
   453 'unfolded' attribute may be replaced by first-class proof text.
   454 
   455 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   456 and command 'unfolding' now all support object-level equalities
   457 (potentially conditional).  The underlying notion of rewrite rule is
   458 analogous to the 'rule_format' attribute, but *not* that of the
   459 Simplifier (which is usually more generous).
   460 
   461 * Isar: the new attribute [rotated n] (default n = 1) rotates the
   462 premises of a theorem by n. Useful in conjunction with drule.
   463 
   464 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   465 method expression within a sandbox consisting of the first N
   466 sub-goals, which need to exist.  For example, ``simp_all [3]''
   467 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   468 simplifies all new goals that emerge from applying rule foo to the
   469 originally first one.
   470 
   471 * Isar: schematic goals are no longer restricted to higher-order
   472 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   473 expected.
   474 
   475 * Isar: the conclusion of a long theorem statement is now either
   476 'shows' (a simultaneous conjunction, as before), or 'obtains'
   477 (essentially a disjunction of cases with local parameters and
   478 assumptions).  The latter allows to express general elimination rules
   479 adequately; in this notation common elimination rules look like this:
   480 
   481   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   482     assumes "EX x. P x"
   483     obtains x where "P x"
   484 
   485   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   486     assumes "A & B"
   487     obtains A and B
   488 
   489   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   490     assumes "A | B"
   491     obtains
   492       A
   493     | B
   494 
   495 The subsequent classical rules even refer to the formal "thesis"
   496 explicitly:
   497 
   498   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   499     obtains "~ thesis"
   500 
   501   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   502     obtains "thesis ==> something"
   503 
   504 The actual proof of an 'obtains' statement is analogous to that of the
   505 Isar proof element 'obtain', only that there may be several cases.
   506 Optional case names may be specified in parentheses; these will be
   507 available both in the present proof and as annotations in the
   508 resulting rule, for later use with the 'cases' method (cf. attribute
   509 case_names).
   510 
   511 * Isar: the assumptions of a long theorem statement are available as
   512 "assms" fact in the proof context.  This is more appropriate than the
   513 (historical) "prems", which refers to all assumptions of the current
   514 context, including those from the target locale, proof body etc.
   515 
   516 * Isar: 'print_statement' prints theorems from the current theory or
   517 proof context in long statement form, according to the syntax of a
   518 top-level lemma.
   519 
   520 * Isar: 'obtain' takes an optional case name for the local context
   521 introduction rule (default "that").
   522 
   523 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   524 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   525 to occur.
   526 
   527 * Pure: syntax "CONST name" produces a fully internalized constant
   528 according to the current context.  This is particularly useful for
   529 syntax translations that should refer to internal constant
   530 representations independently of name spaces.
   531 
   532 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   533 instead of "FOO ". This allows multiple binder declarations to coexist
   534 in the same context.  INCOMPATIBILITY.
   535 
   536 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   537 primitive that also works in a locale context (both for constants and
   538 fixed variables). Type declaration and internal syntactic representation
   539 of given constants retrieved from the context. Likewise, the
   540 'no_notation' command allows to remove given syntax annotations from the
   541 current context.
   542 
   543 * Isar/locales: new derived specification elements 'axiomatization',
   544 'definition', 'abbreviation', which support type-inference, admit
   545 object-level specifications (equality, equivalence).  See also the
   546 isar-ref manual.  Examples:
   547 
   548   axiomatization
   549     eq  (infix "===" 50) where
   550     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   551 
   552   definition "f x y = x + y + 1"
   553   definition g where "g x = f x x"
   554 
   555   abbreviation
   556     neq  (infix "=!=" 50) where
   557     "x =!= y == ~ (x === y)"
   558 
   559 These specifications may be also used in a locale context.  Then the
   560 constants being introduced depend on certain fixed parameters, and the
   561 constant name is qualified by the locale base name.  An internal
   562 abbreviation takes care for convenient input and output, making the
   563 parameters implicit and using the original short name.  See also
   564 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   565 entities from a monomorphic theory.
   566 
   567 Presently, abbreviations are only available 'in' a target locale, but
   568 not inherited by general import expressions.  Also note that
   569 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   570 'translations' in common applications.  The "no_abbrevs" print mode
   571 prevents folding of abbreviations in term output.
   572 
   573 Concrete syntax is attached to specified constants in internal form,
   574 independently of name spaces.  The parse tree representation is
   575 slightly different -- use 'notation' instead of raw 'syntax', and
   576 'translations' with explicit "CONST" markup to accommodate this.
   577 
   578 * Pure/Isar: unified syntax for new-style specification mechanisms
   579 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
   580 full type inference and dummy patterns ("_").  For example:
   581 
   582   definition "K x _ = x"
   583 
   584   inductive conj for A B
   585   where "A ==> B ==> conj A B"
   586 
   587 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   588 the current context.  Print mode "no_abbrevs" prevents inversion of
   589 abbreviations on output.
   590 
   591 * Isar/locales: improved parameter handling: use of locales "var" and
   592 "struct" no longer necessary; - parameter renamings are no longer
   593 required to be injective.  For example, this allows to define
   594 endomorphisms as locale endom = homom mult mult h.
   595 
   596 * Isar/locales: changed the way locales with predicates are defined.
   597 Instead of accumulating the specification, the imported expression is
   598 now an interpretation.  INCOMPATIBILITY: different normal form of
   599 locale expressions.  In particular, in interpretations of locales with
   600 predicates, goals repesenting already interpreted fragments are not
   601 removed automatically.  Use methods `intro_locales' and
   602 `unfold_locales'; see below.
   603 
   604 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   605 provide backward reasoning on locales predicates.  The methods are
   606 aware of interpretations and discharge corresponding goals.
   607 `intro_locales' is less aggressive then `unfold_locales' and does not
   608 unfold predicates to assumptions.
   609 
   610 * Isar/locales: the order in which locale fragments are accumulated
   611 has changed.  This enables to override declarations from fragments due
   612 to interpretations -- for example, unwanted simp rules.
   613 
   614 * Isar/locales: interpretation in theories and proof contexts has been
   615 extended.  One may now specify (and prove) equations, which are
   616 unfolded in interpreted theorems.  This is useful for replacing
   617 defined concepts (constants depending on locale parameters) by
   618 concepts already existing in the target context.  Example:
   619 
   620   interpretation partial_order ["op <= :: [int, int] => bool"]
   621     where "partial_order.less (op <=) (x::int) y = (x < y)"
   622 
   623 Typically, the constant `partial_order.less' is created by a
   624 definition specification element in the context of locale
   625 partial_order.
   626 
   627 * Method "induct": improved internal context management to support
   628 local fixes and defines on-the-fly. Thus explicit meta-level
   629 connectives !!  and ==> are rarely required anymore in inductive goals
   630 (using object-logic connectives for this purpose has been long
   631 obsolete anyway). Common proof patterns are explained in
   632 src/HOL/Induct/Common_Patterns.thy, see also
   633 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
   634 examples.
   635 
   636 * Method "induct": improved handling of simultaneous goals. Instead of
   637 introducing object-level conjunction, the statement is now split into
   638 several conclusions, while the corresponding symbolic cases are nested
   639 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
   640 see src/HOL/Induct/Common_Patterns.thy, for example.
   641 
   642 * Method "induct": mutual induction rules are now specified as a list
   643 of rule sharing the same induction cases. HOL packages usually provide
   644 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
   645 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
   646 mutual induction rules differently, i.e. like this:
   647 
   648   (induct rule: foo_bar.inducts)
   649   (induct set: foo bar)
   650   (induct pred: foo bar)
   651   (induct type: foo bar)
   652 
   653 The ML function ProjectRule.projections turns old-style rules into the
   654 new format.
   655 
   656 * Method "coinduct": dual of induction, see
   657 src/HOL/Library/Coinductive_List.thy for various examples.
   658 
   659 * Method "cases", "induct", "coinduct": the ``(open)'' option is
   660 considered a legacy feature.
   661 
   662 * Attribute "symmetric" produces result with standardized schematic
   663 variables (index 0).  Potential INCOMPATIBILITY.
   664 
   665 * Simplifier: by default the simplifier trace only shows top level
   666 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   667 default. Thus there is less danger of being flooded by the trace. The
   668 trace indicates where parts have been suppressed.
   669   
   670 * Provers/classical: removed obsolete classical version of elim_format
   671 attribute; classical elim/dest rules are now treated uniformly when
   672 manipulating the claset.
   673 
   674 * Provers/classical: stricter checks to ensure that supplied intro,
   675 dest and elim rules are well-formed; dest and elim rules must have at
   676 least one premise.
   677 
   678 * Provers/classical: attributes dest/elim/intro take an optional
   679 weight argument for the rule (just as the Pure versions).  Weights are
   680 ignored by automated tools, but determine the search order of single
   681 rule steps.
   682 
   683 * Syntax: input syntax now supports dummy variable binding "%_. b",
   684 where the body does not mention the bound variable.  Note that dummy
   685 patterns implicitly depend on their context of bounds, which makes
   686 "{_. _}" match any set comprehension as expected.  Potential
   687 INCOMPATIBILITY -- parse translations need to cope with syntactic
   688 constant "_idtdummy" in the binding position.
   689 
   690 * Syntax: removed obsolete syntactic constant "_K" and its associated
   691 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   692 for example "A -> B" => "Pi A (%_. B)".
   693 
   694 * Pure: 'class_deps' command visualizes the subclass relation, using
   695 the graph browser tool.
   696 
   697 * Pure: 'print_theory' now suppresses certain internal declarations by
   698 default; use '!' option for full details.
   699 
   700 
   701 *** HOL ***
   702 
   703 * Method "metis" proves goals by applying the Metis general-purpose
   704 resolution prover (see also http://gilith.com/software/metis/).
   705 Examples are in the directory MetisExamples.  WARNING: the
   706 Isabelle/HOL-Metis integration does not yet work properly with
   707 multi-threading.
   708   
   709 * Command 'sledgehammer' invokes external automatic theorem provers as
   710 background processes.  It generates calls to the "metis" method if
   711 successful. These can be pasted into the proof.  Users do not have to
   712 wait for the automatic provers to return.  WARNING: does not really
   713 work with multi-threading.
   714 
   715 * New "auto_quickcheck" feature tests outermost goal statements for
   716 potential counter-examples.  Controlled by ML references
   717 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
   718 5000 milliseconds).  Fails silently if statements is outside of
   719 executable fragment, or any other codgenerator problem occurs.
   720 
   721 * New constant "undefined" with axiom "undefined x = undefined".
   722 
   723 * Added class "HOL.eq", allowing for code generation with polymorphic
   724 equality.
   725 
   726 * Some renaming of class constants due to canonical name prefixing in
   727 the new 'class' package:
   728 
   729     HOL.abs ~> HOL.abs_class.abs
   730     HOL.divide ~> HOL.divide_class.divide
   731     0 ~> HOL.zero_class.zero
   732     1 ~> HOL.one_class.one
   733     op + ~> HOL.plus_class.plus
   734     op - ~> HOL.minus_class.minus
   735     uminus ~> HOL.minus_class.uminus
   736     op * ~> HOL.times_class.times
   737     op < ~> HOL.ord_class.less
   738     op <= > HOL.ord_class.less_eq
   739     Nat.power ~> Power.power_class.power
   740     Nat.size ~> Nat.size_class.size
   741     Numeral.number_of ~> Numeral.number_class.number_of
   742     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
   743     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
   744     Orderings.min ~> Orderings.ord_class.min
   745     Orderings.max ~> Orderings.ord_class.max
   746     Divides.op div ~> Divides.div_class.div
   747     Divides.op mod ~> Divides.div_class.mod
   748     Divides.op dvd ~> Divides.div_class.dvd
   749 
   750 INCOMPATIBILITY.  Adaptions may be required in the following cases:
   751 
   752 a) User-defined constants using any of the names "plus", "minus",
   753 "times", "less" or "less_eq". The standard syntax translations for
   754 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
   755 names.
   756 
   757 b) Variables named "plus", "minus", "times", "less", "less_eq"
   758 INCOMPATIBILITY: use more specific names.
   759 
   760 c) Permutative equations (e.g. "a + b = b + a")
   761 Since the change of names also changes the order of terms, permutative
   762 rewrite rules may get applied in a different order. Experience shows
   763 that this is rarely the case (only two adaptions in the whole Isabelle
   764 distribution).  INCOMPATIBILITY: rewrite proofs
   765 
   766 d) ML code directly refering to constant names
   767 This in general only affects hand-written proof tactics, simprocs and
   768 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
   769 Consider using @{const_name} antiquotation.
   770 
   771 * New class "default" with associated constant "default".
   772 
   773 * Function "sgn" is now overloaded and available on int, real, complex
   774 (and other numeric types), using class "sgn".  Two possible defs of
   775 sgn are given as equational assumptions in the classes sgn_if and
   776 sgn_div_norm; ordered_idom now also inherits from sgn_if.
   777 INCOMPATIBILITY.
   778 
   779 * Locale "partial_order" now unified with class "order" (cf. theory
   780 Orderings), added parameter "less".  INCOMPATIBILITY.
   781 
   782 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
   783 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
   784 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
   785 
   786 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
   787 changed order of proof goals in instance proofs.
   788 
   789 * The transitivity reasoner for partial and linear orders is set up
   790 for classes "order" and "linorder".  Instances of the reasoner are available
   791 in all contexts importing or interpreting the corresponding locales.
   792 Method "order" invokes the reasoner separately; the reasoner
   793 is also integrated with the Simplifier as a solver.  Diagnostic
   794 command 'print_orders' shows the available instances of the reasoner
   795 in the current context.
   796 
   797 * Localized monotonicity predicate in theory "Orderings"; integrated
   798 lemmas max_of_mono and min_of_mono with this predicate.
   799 INCOMPATIBILITY.
   800 
   801 * Formulation of theorem "dense" changed slightly due to integration
   802 with new class dense_linear_order.
   803 
   804 * Uniform lattice theory development in HOL.
   805 
   806     constants "meet" and "join" now named "inf" and "sup"
   807     constant "Meet" now named "Inf"
   808 
   809     classes "meet_semilorder" and "join_semilorder" now named
   810       "lower_semilattice" and "upper_semilattice"
   811     class "lorder" now named "lattice"
   812     class "comp_lat" now named "complete_lattice"
   813 
   814     Instantiation of lattice classes allows explicit definitions
   815     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
   816 
   817   INCOMPATIBILITY.  Theorem renames:
   818 
   819     meet_left_le            ~> inf_le1
   820     meet_right_le           ~> inf_le2
   821     join_left_le            ~> sup_ge1
   822     join_right_le           ~> sup_ge2
   823     meet_join_le            ~> inf_sup_ord
   824     le_meetI                ~> le_infI
   825     join_leI                ~> le_supI
   826     le_meet                 ~> le_inf_iff
   827     le_join                 ~> ge_sup_conv
   828     meet_idempotent         ~> inf_idem
   829     join_idempotent         ~> sup_idem
   830     meet_comm               ~> inf_commute
   831     join_comm               ~> sup_commute
   832     meet_leI1               ~> le_infI1
   833     meet_leI2               ~> le_infI2
   834     le_joinI1               ~> le_supI1
   835     le_joinI2               ~> le_supI2
   836     meet_assoc              ~> inf_assoc
   837     join_assoc              ~> sup_assoc
   838     meet_left_comm          ~> inf_left_commute
   839     meet_left_idempotent    ~> inf_left_idem
   840     join_left_comm          ~> sup_left_commute
   841     join_left_idempotent    ~> sup_left_idem
   842     meet_aci                ~> inf_aci
   843     join_aci                ~> sup_aci
   844     le_def_meet             ~> le_iff_inf
   845     le_def_join             ~> le_iff_sup
   846     join_absorp2            ~> sup_absorb2
   847     join_absorp1            ~> sup_absorb1
   848     meet_absorp1            ~> inf_absorb1
   849     meet_absorp2            ~> inf_absorb2
   850     meet_join_absorp        ~> inf_sup_absorb
   851     join_meet_absorp        ~> sup_inf_absorb
   852     distrib_join_le         ~> distrib_sup_le
   853     distrib_meet_le         ~> distrib_inf_le
   854 
   855     add_meet_distrib_left   ~> add_inf_distrib_left
   856     add_join_distrib_left   ~> add_sup_distrib_left
   857     is_join_neg_meet        ~> is_join_neg_inf
   858     is_meet_neg_join        ~> is_meet_neg_sup
   859     add_meet_distrib_right  ~> add_inf_distrib_right
   860     add_join_distrib_right  ~> add_sup_distrib_right
   861     add_meet_join_distribs  ~> add_sup_inf_distribs
   862     join_eq_neg_meet        ~> sup_eq_neg_inf
   863     meet_eq_neg_join        ~> inf_eq_neg_sup
   864     add_eq_meet_join        ~> add_eq_inf_sup
   865     meet_0_imp_0            ~> inf_0_imp_0
   866     join_0_imp_0            ~> sup_0_imp_0
   867     meet_0_eq_0             ~> inf_0_eq_0
   868     join_0_eq_0             ~> sup_0_eq_0
   869     neg_meet_eq_join        ~> neg_inf_eq_sup
   870     neg_join_eq_meet        ~> neg_sup_eq_inf
   871     join_eq_if              ~> sup_eq_if
   872 
   873     mono_meet               ~> mono_inf
   874     mono_join               ~> mono_sup
   875     meet_bool_eq            ~> inf_bool_eq
   876     join_bool_eq            ~> sup_bool_eq
   877     meet_fun_eq             ~> inf_fun_eq
   878     join_fun_eq             ~> sup_fun_eq
   879     meet_set_eq             ~> inf_set_eq
   880     join_set_eq             ~> sup_set_eq
   881     meet1_iff               ~> inf1_iff
   882     meet2_iff               ~> inf2_iff
   883     meet1I                  ~> inf1I
   884     meet2I                  ~> inf2I
   885     meet1D1                 ~> inf1D1
   886     meet2D1                 ~> inf2D1
   887     meet1D2                 ~> inf1D2
   888     meet2D2                 ~> inf2D2
   889     meet1E                  ~> inf1E
   890     meet2E                  ~> inf2E
   891     join1_iff               ~> sup1_iff
   892     join2_iff               ~> sup2_iff
   893     join1I1                 ~> sup1I1
   894     join2I1                 ~> sup2I1
   895     join1I1                 ~> sup1I1
   896     join2I2                 ~> sup1I2
   897     join1CI                 ~> sup1CI
   898     join2CI                 ~> sup2CI
   899     join1E                  ~> sup1E
   900     join2E                  ~> sup2E
   901 
   902     is_meet_Meet            ~> is_meet_Inf
   903     Meet_bool_def           ~> Inf_bool_def
   904     Meet_fun_def            ~> Inf_fun_def
   905     Meet_greatest           ~> Inf_greatest
   906     Meet_lower              ~> Inf_lower
   907     Meet_set_def            ~> Inf_set_def
   908 
   909     Sup_def                 ~> Sup_Inf
   910     Sup_bool_eq             ~> Sup_bool_def
   911     Sup_fun_eq              ~> Sup_fun_def
   912     Sup_set_eq              ~> Sup_set_def
   913 
   914     listsp_meetI            ~> listsp_infI
   915     listsp_meet_eq          ~> listsp_inf_eq
   916 
   917     meet_min                ~> inf_min
   918     join_max                ~> sup_max
   919 
   920 * Added syntactic class "size"; overloaded constant "size" now has
   921 type "'a::size ==> bool"
   922 
   923 * Internal reorganisation of `size' of datatypes: size theorems
   924 "foo.size" are no longer subsumed by "foo.simps" (but are still
   925 simplification rules by default!); theorems "prod.size" now named
   926 "*.size".
   927 
   928 * Class "div" now inherits from class "times" rather than "type".
   929 INCOMPATIBILITY.
   930 
   931 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
   932 Linorder etc.  have disappeared; operations defined in terms of
   933 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
   934 
   935 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
   936 
   937 * HOL-Word: New extensive library and type for generic, fixed size
   938 machine words, with arithemtic, bit-wise, shifting and rotating
   939 operations, reflection into int, nat, and bool lists, automation for
   940 linear arithmetic (by automatic reflection into nat or int), including
   941 lemmas on overflow and monotonicity.  Instantiated to all appropriate
   942 arithmetic type classes, supporting automatic simplification of
   943 numerals on all operations.
   944 
   945 * Library/Boolean_Algebra: locales for abstract boolean algebras.
   946 
   947 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
   948 
   949 * Code generator library theories:
   950   - Code_Integer represents HOL integers by big integer literals in target
   951     languages.
   952   - Code_Char represents HOL characters by character literals in target
   953     languages.
   954   - Code_Char_chr like Code_Char, but also offers treatment of character
   955     codes; includes Code_Integer.
   956   - Executable_Set allows to generate code for finite sets using lists.
   957   - Executable_Rat implements rational numbers as triples (sign, enumerator,
   958     denominator).
   959   - Executable_Real implements a subset of real numbers, namly those
   960     representable by rational numbers.
   961   - Efficient_Nat implements natural numbers by integers, which in general will
   962     result in higher efficency; pattern matching with 0/Suc is eliminated;
   963     includes Code_Integer.
   964   - Code_Index provides an additional datatype index which is mapped to
   965     target-language built-in integers.
   966   - Code_Message provides an additional datatype message_string} which is isomorphic to
   967     strings; messages are mapped to target-language strings.
   968 
   969 * New package for inductive predicates
   970 
   971   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
   972 
   973     inductive
   974       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   975       for z_1 :: U_1 and ... and z_n :: U_m
   976     where
   977       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   978     | ...
   979 
   980   with full support for type-inference, rather than
   981 
   982     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   983 
   984     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   985     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   986 
   987     inductive "s z_1 ... z_m"
   988     intros
   989       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   990       ...
   991 
   992   For backward compatibility, there is a wrapper allowing inductive
   993   sets to be defined with the new package via
   994 
   995     inductive_set
   996       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   997       for z_1 :: U_1 and ... and z_n :: U_m
   998     where
   999       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1000     | ...
  1001 
  1002   or
  1003 
  1004     inductive_set
  1005       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1006       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1007       for z_1 :: U_1 and ... and z_n :: U_m
  1008     where
  1009       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1010     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1011     | ...
  1012 
  1013   if the additional syntax "p ..." is required.
  1014 
  1015   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1016   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1017 
  1018   INCOMPATIBILITIES:
  1019 
  1020   - Since declaration and definition of inductive sets or predicates
  1021     is no longer separated, abbreviations involving the newly
  1022     introduced sets or predicates must be specified together with the
  1023     introduction rules after the 'where' keyword (see above), rather
  1024     than before the actual inductive definition.
  1025 
  1026   - The variables in induction and elimination rules are now
  1027     quantified in the order of their occurrence in the introduction
  1028     rules, rather than in alphabetical order. Since this may break
  1029     some proofs, these proofs either have to be repaired, e.g. by
  1030     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1031     statements of the form
  1032 
  1033       case (rule_i a_i_1 ... a_i_{k_i})
  1034 
  1035     or the old order of quantification has to be restored by explicitly adding
  1036     meta-level quantifiers in the introduction rules, i.e.
  1037 
  1038       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1039 
  1040   - The format of the elimination rules is now
  1041 
  1042       p z_1 ... z_m x_1 ... x_n ==>
  1043         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1044         ==> ... ==> P
  1045 
  1046     for predicates and
  1047 
  1048       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1049         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1050         ==> ... ==> P
  1051 
  1052     for sets rather than
  1053 
  1054       x : s z_1 ... z_m ==>
  1055         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1056         ==> ... ==> P
  1057 
  1058     This may require terms in goals to be expanded to n-tuples
  1059     (e.g. using case_tac or simplification with the split_paired_all
  1060     rule) before the above elimination rule is applicable.
  1061 
  1062   - The elimination or case analysis rules for (mutually) inductive
  1063     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1064     list of rules "p_1_..._p_k.elims" is no longer available.
  1065 
  1066 * New package "function"/"fun" for general recursive functions,
  1067 supporting mutual and nested recursion, definitions in local contexts,
  1068 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1069 for small examples, and the separate tutorial on the function
  1070 package. The old recdef "package" is still available as before, but
  1071 users are encouraged to use the new package.
  1072 
  1073 * Method "lexicographic_order" automatically synthesizes termination
  1074 relations as lexicographic combinations of size measures. 
  1075 
  1076 * Case-expressions allow arbitrary constructor-patterns (including
  1077 "_") and take their order into account, like in functional
  1078 programming.  Internally, this is translated into nested
  1079 case-expressions; missing cases are added and mapped to the predefined
  1080 constant "undefined". In complicated cases printing may no longer show
  1081 the original input but the internal form. Lambda-abstractions allow
  1082 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1083 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1084 variable.
  1085 
  1086 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1087 is an abbreviation for "of_nat :: nat => int". The simplification
  1088 rules for "of_nat" have been changed to work like "int" did
  1089 previously.  Potential INCOMPATIBILITY:
  1090   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1091   - of_nat_diff and of_nat_mult are no longer default simp rules
  1092 
  1093 * Method "algebra" solves polynomial equations over (semi)rings using
  1094 Groebner bases. The (semi)ring structure is defined by locales and the
  1095 tool setup depends on that generic context. Installing the method for
  1096 a specific type involves instantiating the locale and possibly adding
  1097 declarations for computation on the coefficients.  The method is
  1098 already instantiated for natural numbers and for the axiomatic class
  1099 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1100 CALCULEMUS 2007 for the general principles underlying this
  1101 architecture of context-aware proof-tools.
  1102 
  1103 * Method "ferrack" implements quantifier elimination over
  1104 special-purpose dense linear orders using locales (analogous to
  1105 "algebra"). The method is already installed for class
  1106 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1107 rat, etc.
  1108 
  1109 * Former constant "List.op @" now named "List.append".  Use ML
  1110 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1111 circumvent possible incompatibilities when working on ML level.
  1112 
  1113 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1114 
  1115 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1116 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1117 
  1118 * New syntax for Haskell-like list comprehension (input only), eg.
  1119 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1120 
  1121 * The special syntax for function "filter" has changed from [x :
  1122 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1123 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1124 
  1125 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1126 defined on nat only, as an abbreviation for [a..<Suc b]
  1127 INCOMPATIBILITY.
  1128 
  1129 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1130 
  1131 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1132 
  1133 * New lemma collection field_simps (an extension of ring_simps) for
  1134 manipulating (in)equations involving division. Multiplies with all
  1135 denominators that can be proved to be non-zero (in equations) or
  1136 positive/negative (in inequations).
  1137 
  1138 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1139 have been improved and renamed to ring_simps, group_simps and
  1140 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1141 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1142 
  1143 * Theory Library/Commutative_Ring: switched from recdef to function
  1144 package; constants add, mul, pow now curried.  Infix syntax for
  1145 algebraic operations.
  1146 
  1147 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1148 INCOMPATIBILITY.
  1149 
  1150 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1151 INCOMPATIBILITY.
  1152 
  1153 * HOL/records: generalised field-update to take a function on the
  1154 field rather than the new value: r(|A := x|) is translated to A_update
  1155 (K x) r The K-combinator that is internally used is called K_record.
  1156 INCOMPATIBILITY: Usage of the plain update functions has to be
  1157 adapted.
  1158  
  1159 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1160 * x = 0, which are required for a semiring.  Richer structures do not
  1161 inherit from semiring_0 anymore, because this property is a theorem
  1162 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1163 there is more to prove, but this is mostly trivial.
  1164 
  1165 * Class "recpower" is generalized to arbitrary monoids, not just
  1166 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1167 commutativity or semiring properties additionally.
  1168 
  1169 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1170 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1171 better use 'abbreviation'.
  1172 
  1173 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1174 
  1175 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1176 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1177 significant changes for setting up numeral syntax for types:
  1178   - New constants Numeral.pred and Numeral.succ instead
  1179       of former Numeral.bin_pred and Numeral.bin_succ.
  1180   - Use integer operations instead of bin_add, bin_mult and so on.
  1181   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1182   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1183 
  1184 See src/HOL/Integ/IntArith.thy for an example setup.
  1185 
  1186 * Command 'normal_form' computes the normal form of a term that may
  1187 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1188 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1189 heavy-duty computations because the functions are compiled to ML
  1190 first.  Correspondingly, a method "normalization" is provided.  See
  1191 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1192 
  1193 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1194 25 like -->); output depends on the "iff" print_mode, the default is
  1195 "A = B" (with priority 50).
  1196 
  1197 * Relations less (<) and less_eq (<=) are also available on type bool.
  1198 Modified syntax to disallow nesting without explicit parentheses,
  1199 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1200 INCOMPATIBILITY.
  1201 
  1202 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1203 
  1204 * Relation composition operator "op O" now has precedence 75 and binds
  1205 stronger than union and intersection. INCOMPATIBILITY.
  1206 
  1207 * The old set interval syntax "{m..n(}" (and relatives) has been
  1208 removed.  Use "{m..<n}" (and relatives) instead.
  1209 
  1210 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1211 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1212 ``declare [[simproc del: neq]]''.
  1213 
  1214 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1215 True/False.
  1216 
  1217 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1218 
  1219 * Theorem setsum_mult renamed to setsum_right_distrib.
  1220 
  1221 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1222 ``rule'' method.
  1223 
  1224 * Reimplemented methods "sat" and "satx", with several improvements:
  1225 goals no longer need to be stated as "<prems> ==> False", equivalences
  1226 (i.e. "=" on type bool) are handled, variable names of the form
  1227 "lit_<n>" are no longer reserved, significant speedup.
  1228 
  1229 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1230 zChaff is still supported as well.
  1231 
  1232 * 'inductive' and 'datatype': provide projections of mutual rules,
  1233 bundled as foo_bar.inducts;
  1234 
  1235 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1236 Library.
  1237 
  1238 * Library: moved theory Accessible_Part to main HOL.
  1239 
  1240 * Library: added theory Coinductive_List of potentially infinite lists
  1241 as greatest fixed-point.
  1242 
  1243 * Library: added theory AssocList which implements (finite) maps as
  1244 association lists.
  1245 
  1246 * Method "evaluation" solves goals (i.e. a boolean expression)
  1247 efficiently by compiling it to ML.  The goal is "proved" (via an
  1248 oracle) if it evaluates to True.
  1249 
  1250 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1251 also when invoked by the simplifier.  This results in the Simplifier
  1252 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1253 Configuration option fast_arith_split_limit=0 recovers the old
  1254 behavior.
  1255 
  1256 * Support for hex (0x20) and binary (0b1001) numerals.
  1257 
  1258 * New method: reify eqs (t), where eqs are equations for an
  1259 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1260 parameter, computes a term s::'b and a list xs::'a list and proves the
  1261 theorem I xs s = t. This is also known as reification or quoting. The
  1262 resulting theorem is applied to the subgoal to substitute t with I xs
  1263 s.  If t is omitted, the subgoal itself is reified.
  1264 
  1265 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1266 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1267 where f is supposed to be a computable function (in the sense of code
  1268 generattion). The method uses reify to compute s and xs as above then
  1269 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1270 r and finally gets the theorem t = r, which is again applied to the
  1271 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1272 
  1273 * Reflection: Automatic reification now handels binding, an example is
  1274 available in src/HOL/ex/ReflectionEx.thy
  1275 
  1276 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1277 command 'statespace' that is similar to 'record', but introduces an
  1278 abstract specification based on the locale infrastructure instead of
  1279 HOL types.  This leads to extra flexibility in composing state spaces,
  1280 in particular multiple inheritance and renaming of components.
  1281 
  1282 
  1283 *** HOL-Complex ***
  1284 
  1285 * Hyperreal: Functions root and sqrt are now defined on negative real
  1286 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1287 Nonnegativity side conditions have been removed from many lemmas, so
  1288 that more subgoals may now be solved by simplification; potential
  1289 INCOMPATIBILITY.
  1290 
  1291 * Real: new type classes formalize real normed vector spaces and
  1292 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1293 and norm :: 'a => real.
  1294 
  1295 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1296 reals into other types. The overloaded constant Reals :: 'a set is now
  1297 defined as range of_real; potential INCOMPATIBILITY.
  1298 
  1299 * Real: proper support for ML code generation, including 'quickcheck'.
  1300 Reals are implemented as arbitrary precision rationals.
  1301 
  1302 * Hyperreal: Several constants that previously worked only for the
  1303 reals have been generalized, so they now work over arbitrary vector
  1304 spaces. Type annotations may need to be added in some cases; potential
  1305 INCOMPATIBILITY.
  1306 
  1307   Infinitesimal  :: ('a::real_normed_vector) star set
  1308   HFinite        :: ('a::real_normed_vector) star set
  1309   HInfinite      :: ('a::real_normed_vector) star set
  1310   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1311   monad          :: ('a::real_normed_vector) star => 'a star set
  1312   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1313   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1314   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1315   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1316   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1317   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1318   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1319   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1320   sgn            :: 'a::real_normed_vector => 'a
  1321   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1322 
  1323 * Complex: Some complex-specific constants are now abbreviations for
  1324 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1325 hnorm.  Other constants have been entirely removed in favor of the
  1326 polymorphic versions (INCOMPATIBILITY):
  1327 
  1328   approx        <-- capprox
  1329   HFinite       <-- CFinite
  1330   HInfinite     <-- CInfinite
  1331   Infinitesimal <-- CInfinitesimal
  1332   monad         <-- cmonad
  1333   galaxy        <-- cgalaxy
  1334   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1335   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1336   (ns)deriv     <-- (ns)cderiv
  1337 
  1338 
  1339 *** HOL-Algebra ***
  1340 
  1341 * Formalisation of ideals and the quotient construction over rings.
  1342 
  1343 * Order and lattice theory no longer based on records.
  1344 INCOMPATIBILITY.
  1345 
  1346 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1347 greatest_closed.  INCOMPATIBILITY.
  1348 
  1349 * Method algebra is now set up via an attribute.  For examples see
  1350 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1351 of algebraic structures.
  1352 
  1353 * Renamed theory CRing to Ring.
  1354 
  1355 
  1356 *** HOL-Nominal ***
  1357 
  1358 * Substantial, yet incomplete support for nominal datatypes (binding
  1359 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  1360 src/HOL/Nominal/Examples.  Prospective users should consult
  1361 http://isabelle.in.tum.de/nominal/
  1362 
  1363 
  1364 *** ML ***
  1365 
  1366 * ML basics: just one true type int, which coincides with IntInf.int
  1367 (even on SML/NJ).
  1368 
  1369 * ML within Isar: antiquotations allow to embed statically-checked
  1370 formal entities in the source, referring to the context available at
  1371 compile-time.  For example:
  1372 
  1373 ML {* @{sort "{zero,one}"} *}
  1374 ML {* @{typ "'a => 'b"} *}
  1375 ML {* @{term "%x. x"} *}
  1376 ML {* @{prop "x == y"} *}
  1377 ML {* @{ctyp "'a => 'b"} *}
  1378 ML {* @{cterm "%x. x"} *}
  1379 ML {* @{cprop "x == y"} *}
  1380 ML {* @{thm asm_rl} *}
  1381 ML {* @{thms asm_rl} *}
  1382 ML {* @{type_name c} *}
  1383 ML {* @{type_syntax c} *}
  1384 ML {* @{const_name c} *}
  1385 ML {* @{const_syntax c} *}
  1386 ML {* @{context} *}
  1387 ML {* @{theory} *}
  1388 ML {* @{theory Pure} *}
  1389 ML {* @{theory_ref} *}
  1390 ML {* @{theory_ref Pure} *}
  1391 ML {* @{simpset} *}
  1392 ML {* @{claset} *}
  1393 ML {* @{clasimpset} *}
  1394 
  1395 The same works for sources being ``used'' within an Isar context.
  1396 
  1397 * ML in Isar: improved error reporting; extra verbosity with
  1398 ML_Context.trace enabled.
  1399 
  1400 * Pure/General/table.ML: the join operations now works via exceptions
  1401 DUP/SAME instead of type option. This is simpler in simple cases, and
  1402 admits slightly more efficient complex applications.
  1403 
  1404 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1405 use Context.generic instead of just theory.
  1406 
  1407 * Pure: datatype Context.generic joins theory/Proof.context and
  1408 provides some facilities for code that works in either kind of
  1409 context, notably GenericDataFun for uniform theory and proof data.
  1410 
  1411 * Pure: simplified internal attribute type, which is now always
  1412 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  1413 local (Proof.context) attributes have been discontinued, while
  1414 minimizing code duplication. Thm.rule_attribute and
  1415 Thm.declaration_attribute build canonical attributes; see also structure
  1416 Context for further operations on Context.generic, notably
  1417 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  1418 declarations and definitions.
  1419 
  1420 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1421 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1422 init only required for impure data. INCOMPATIBILITY: empty really need
  1423 to be empty (no dependencies on theory content!)
  1424 
  1425 * Pure/kernel: consts certification ignores sort constraints given in
  1426 signature declarations. (This information is not relevant to the
  1427 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  1428 potential INCOMPATIBILITY.
  1429 
  1430 * Pure: axiomatic type classes are now purely definitional, with
  1431 explicit proofs of class axioms and super class relations performed
  1432 internally. See Pure/axclass.ML for the main internal interfaces --
  1433 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1434 AxClass.axiomatize_class/classrel/arity supersede
  1435 Sign.add_classes/classrel/arities.
  1436 
  1437 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1438 global/local versions on theory vs. Proof.context have been
  1439 discontinued; Attrib.syntax and Method.syntax have been adapted
  1440 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1441 attributes, methods, etc.
  1442 
  1443 * Pure: several functions of signature "... -> theory -> theory * ..."
  1444 have been reoriented to "... -> theory -> ... * theory" in order to
  1445 allow natural usage in combination with the ||>, ||>>, |-> and
  1446 fold_map combinators.
  1447 
  1448 * Pure: official theorem names (closed derivations) and additional
  1449 comments (tags) are now strictly separate.  Name hints -- which are
  1450 maintained as tags -- may be attached any time without affecting the
  1451 derivation.
  1452 
  1453 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1454 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1455 achieve the old behaviour.
  1456 
  1457 * Pure: the "Goal" constant is now called "prop", supporting a
  1458 slightly more general idea of ``protecting'' meta-level rule
  1459 statements.
  1460 
  1461 * Pure: Logic.(un)varify only works in a global context, which is now
  1462 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1463 Logic.legacy_(un)varify as temporary workaround.
  1464 
  1465 * Pure: structure Name provides scalable operations for generating
  1466 internal variable names, notably Name.variants etc.  This replaces
  1467 some popular functions from term.ML:
  1468 
  1469   Term.variant		->  Name.variant
  1470   Term.variantlist	->  Name.variant_list
  1471   Term.invent_names	->  Name.invent_list
  1472 
  1473 Note that low-level renaming rarely occurs in new code -- operations
  1474 from structure Variable are used instead (see below).
  1475 
  1476 * Pure: structure Variable provides fundamental operations for proper
  1477 treatment of fixed/schematic variables in a context.  For example,
  1478 Variable.import introduces fixes for schematics of given facts and
  1479 Variable.export reverses the effect (up to renaming) -- this replaces
  1480 various freeze_thaw operations.
  1481 
  1482 * Pure: structure Goal provides simple interfaces for
  1483 init/conclude/finish and tactical prove operations (replacing former
  1484 Tactic.prove).  Goal.prove is the canonical way to prove results
  1485 within a given context; Goal.prove_global is a degraded version for
  1486 theory level goals, including a global Drule.standard.  Note that
  1487 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1488 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1489 in a locale context).
  1490 
  1491 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  1492 and type checking (Syntax.check_term etc.), with common combinations
  1493 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  1494 which are considered legacy and await removal.
  1495 
  1496 * Pure/Syntax: generic interfaces for type unchecking
  1497 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  1498 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  1499 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  1500 available for convenience, but refer to the very same operations using
  1501 a mere theory instead of a full context.
  1502 
  1503 * Isar: simplified treatment of user-level errors, using exception
  1504 ERROR of string uniformly.  Function error now merely raises ERROR,
  1505 without any side effect on output channels.  The Isar toplevel takes
  1506 care of proper display of ERROR exceptions.  ML code may use plain
  1507 handle/can/try; cat_error may be used to concatenate errors like this:
  1508 
  1509   ... handle ERROR msg => cat_error msg "..."
  1510 
  1511 Toplevel ML code (run directly or through the Isar toplevel) may be
  1512 embedded into the Isar toplevel with exception display/debug like
  1513 this:
  1514 
  1515   Isar.toplevel (fn () => ...)
  1516 
  1517 INCOMPATIBILITY, removed special transform_error facilities, removed
  1518 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1519 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1520 -- use plain ERROR instead.
  1521 
  1522 * Isar: theory setup now has type (theory -> theory), instead of a
  1523 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1524 
  1525 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  1526 ProofContext.debug/verbose flags.
  1527 
  1528 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1529 theory before entering a proof state.  Transactions now always see a
  1530 quasi-functional intermediate checkpoint, both in interactive and
  1531 batch mode.
  1532 
  1533 * Isar: simplified interfaces for outer syntax.  Renamed
  1534 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  1535 OuterSyntax.add_parsers -- this functionality is now included in
  1536 OuterSyntax.command etc.  INCOMPATIBILITY.
  1537 
  1538 * Simplifier: the simpset of a running simplification process now
  1539 contains a proof context (cf. Simplifier.the_context), which is the
  1540 very context that the initial simpset has been retrieved from (by
  1541 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1542 (solver, looper etc.) may depend on arbitrary proof data.
  1543 
  1544 * Simplifier.inherit_context inherits the proof context (plus the
  1545 local bounds) of the current simplification process; any simproc
  1546 etc. that calls the Simplifier recursively should do this!  Removed
  1547 former Simplifier.inherit_bounds, which is already included here --
  1548 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1549 specify an explicit context using Simplifier.context/theory_context.
  1550 
  1551 * Simplifier/Classical Reasoner: more abstract interfaces
  1552 change_simpset/claset for modifying the simpset/claset reference of a
  1553 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1554 INCOMPATIBILITY.
  1555 
  1556 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1557 "Trueprop" etc.
  1558 
  1559 
  1560 *** System ***
  1561 
  1562 * settings: the default heap location within ISABELLE_HOME_USER now
  1563 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  1564 Isabelle installations.
  1565 
  1566 * isabelle-process: option -S (secure mode) disables some critical
  1567 operations, notably runtime compilation and evaluation of ML source
  1568 code.
  1569 
  1570 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  1571 
  1572 * Support for parallel execution, using native multicore support of
  1573 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  1574 independent theories, according to the given theory header
  1575 specifications. The maximum number of worker threads is specified via
  1576 usedir option -M or the "max-threads" setting in Proof General. A
  1577 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  1578 to 6 on a 8-core machine.  User-code needs to observe certain
  1579 guidelines for thread-safe programming, see appendix A in the Isar
  1580 Implementation manual.
  1581 
  1582 
  1583 
  1584 New in Isabelle2005 (October 2005)
  1585 ----------------------------------
  1586 
  1587 *** General ***
  1588 
  1589 * Theory headers: the new header syntax for Isar theories is
  1590 
  1591   theory <name>
  1592   imports <theory1> ... <theoryN>
  1593   uses <file1> ... <fileM>
  1594   begin
  1595 
  1596 where the 'uses' part is optional.  The previous syntax
  1597 
  1598   theory <name> = <theory1> + ... + <theoryN>:
  1599 
  1600 will disappear in the next release.  Use isatool fixheaders to convert
  1601 existing theory files.  Note that there is no change in ancient
  1602 non-Isar theories now, but these will disappear soon.
  1603 
  1604 * Theory loader: parent theories can now also be referred to via
  1605 relative and absolute paths.
  1606 
  1607 * Command 'find_theorems' searches for a list of criteria instead of a
  1608 list of constants. Known criteria are: intro, elim, dest, name:string,
  1609 simp:term, and any term. Criteria can be preceded by '-' to select
  1610 theorems that do not match. Intro, elim, dest select theorems that
  1611 match the current goal, name:s selects theorems whose fully qualified
  1612 name contain s, and simp:term selects all simplification rules whose
  1613 lhs match term.  Any other term is interpreted as pattern and selects
  1614 all theorems matching the pattern. Available in ProofGeneral under
  1615 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1616 
  1617   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1618 
  1619 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1620 matching the current goal as introduction rule and not having "HOL."
  1621 in their name (i.e. not being defined in theory HOL).
  1622 
  1623 * Command 'thms_containing' has been discontinued in favour of
  1624 'find_theorems'; INCOMPATIBILITY.
  1625 
  1626 * Communication with Proof General is now 8bit clean, which means that
  1627 Unicode text in UTF-8 encoding may be used within theory texts (both
  1628 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1629 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1630 
  1631   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1632   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1633 
  1634 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1635 Classical Reasoner.  Typical big applications run around 2 times
  1636 faster.
  1637 
  1638 
  1639 *** Document preparation ***
  1640 
  1641 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1642 of raw sources.  Only those symbols that do not require additional
  1643 LaTeX packages (depending on comments in isabellesym.sty) are
  1644 displayed properly, everything else is left verbatim.  isatool display
  1645 and isatool print are used as front ends (these are subject to the
  1646 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1647 
  1648 * Command tags control specific markup of certain regions of text,
  1649 notably folding and hiding.  Predefined tags include "theory" (for
  1650 theory begin and end), "proof" for proof commands, and "ML" for
  1651 commands involving ML code; the additional tags "visible" and
  1652 "invisible" are unused by default.  Users may give explicit tag
  1653 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1654 interpretation of tags is determined by the LaTeX job during document
  1655 preparation: see option -V of isatool usedir, or options -n and -t of
  1656 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1657 \isadroptag.
  1658 
  1659 Several document versions may be produced at the same time via isatool
  1660 usedir (the generated index.html will link all of them).  Typical
  1661 specifications include ''-V document=theory,proof,ML'' to present
  1662 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1663 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1664 these parts without any formal replacement text.  The Isabelle site
  1665 default settings produce ''document'' and ''outline'' versions as
  1666 specified above.
  1667 
  1668 * Several new antiquotations:
  1669 
  1670   @{term_type term} prints a term with its type annotated;
  1671 
  1672   @{typeof term} prints the type of a term;
  1673 
  1674   @{const const} is the same as @{term const}, but checks that the
  1675   argument is a known logical constant;
  1676 
  1677   @{term_style style term} and @{thm_style style thm} print a term or
  1678   theorem applying a "style" to it
  1679 
  1680   @{ML text}
  1681 
  1682 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1683 definitions, equations, inequations etc., 'concl' printing only the
  1684 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1685 to print the specified premise.  TermStyle.add_style provides an ML
  1686 interface for introducing further styles.  See also the "LaTeX Sugar"
  1687 document practical applications.  The ML antiquotation prints
  1688 type-checked ML expressions verbatim.
  1689 
  1690 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1691 and 'text' support optional locale specification '(in loc)', which
  1692 specifies the default context for interpreting antiquotations.  For
  1693 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1694 
  1695 * Option 'locale=NAME' of antiquotations specifies an alternative
  1696 context interpreting the subsequent argument.  For example: @{thm
  1697 [locale=lattice] inf_assoc}.
  1698 
  1699 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1700 a proof context.
  1701 
  1702 * Proper output of antiquotations for theory commands involving a
  1703 proof context (such as 'locale' or 'theorem (in loc) ...').
  1704 
  1705 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1706 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1707 
  1708 * isatool usedir: new option -C (default true) controls whether option
  1709 -D should include a copy of the original document directory; -C false
  1710 prevents unwanted effects such as copying of administrative CVS data.
  1711 
  1712 
  1713 *** Pure ***
  1714 
  1715 * Considerably improved version of 'constdefs' command.  Now performs
  1716 automatic type-inference of declared constants; additional support for
  1717 local structure declarations (cf. locales and HOL records), see also
  1718 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1719 sequential dependencies of definitions within a single 'constdefs'
  1720 section; moreover, the declared name needs to be an identifier.  If
  1721 all fails, consider to fall back on 'consts' and 'defs' separately.
  1722 
  1723 * Improved indexed syntax and implicit structures.  First of all,
  1724 indexed syntax provides a notational device for subscripted
  1725 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1726 expressions.  Secondly, in a local context with structure
  1727 declarations, number indexes \<^sub>n or the empty index (default
  1728 number 1) refer to a certain fixed variable implicitly; option
  1729 show_structs controls printing of implicit structures.  Typical
  1730 applications of these concepts involve record types and locales.
  1731 
  1732 * New command 'no_syntax' removes grammar declarations (and
  1733 translations) resulting from the given syntax specification, which is
  1734 interpreted in the same manner as for the 'syntax' command.
  1735 
  1736 * 'Advanced' translation functions (parse_translation etc.) may depend
  1737 on the signature of the theory context being presently used for
  1738 parsing/printing, see also isar-ref manual.
  1739 
  1740 * Improved 'oracle' command provides a type-safe interface to turn an
  1741 ML expression of type theory -> T -> term into a primitive rule of
  1742 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1743 is already included here); see also FOL/ex/IffExample.thy;
  1744 INCOMPATIBILITY.
  1745 
  1746 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1747 before); "cI" is no longer bound, use "c.intro" instead.
  1748 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1749 axclasses vs. locales.
  1750 
  1751 * Improved internal renaming of symbolic identifiers -- attach primes
  1752 instead of base 26 numbers.
  1753 
  1754 * New flag show_question_marks controls printing of leading question
  1755 marks in schematic variable names.
  1756 
  1757 * In schematic variable names, *any* symbol following \<^isub> or
  1758 \<^isup> is now treated as part of the base name.  For example, the
  1759 following works without printing of awkward ".0" indexes:
  1760 
  1761   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1762     by simp
  1763 
  1764 * Inner syntax includes (*(*nested*) comments*).
  1765 
  1766 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1767 annotations as "(00...)".
  1768 
  1769 * Clear separation of logical types and nonterminals, where the latter
  1770 may only occur in 'syntax' specifications or type abbreviations.
  1771 Before that distinction was only partially implemented via type class
  1772 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1773 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1774 exotic syntax specifications may require further adaption
  1775 (e.g. Cube/Cube.thy).
  1776 
  1777 * Removed obsolete type class "logic", use the top sort {} instead.
  1778 Note that non-logical types should be declared as 'nonterminals'
  1779 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1780 specifications.
  1781 
  1782 * Attributes 'induct' and 'cases': type or set names may now be
  1783 locally fixed variables as well.
  1784 
  1785 * Simplifier: can now control the depth to which conditional rewriting
  1786 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1787 Limit.
  1788 
  1789 * Simplifier: simplification procedures may now take the current
  1790 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1791 interface), which is very useful for calling the Simplifier
  1792 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1793 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1794 low-level mk_simproc no longer applies Logic.varify internally, to
  1795 allow for use in a context of fixed variables.
  1796 
  1797 * thin_tac now works even if the assumption being deleted contains !!
  1798 or ==>.  More generally, erule now works even if the major premise of
  1799 the elimination rule contains !! or ==>.
  1800 
  1801 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1802 
  1803 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1804 from Pure, which contains all common declarations already.  Both
  1805 theories are defined via plain Isabelle/Isar .thy files.
  1806 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1807 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1808 use isatool fixcpure to adapt your theory and ML sources.
  1809 
  1810 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1811 selections of theorems in named facts via index ranges.
  1812 
  1813 * 'print_theorems': in theory mode, really print the difference
  1814 wrt. the last state (works for interactive theory development only),
  1815 in proof mode print all local facts (cf. 'print_facts');
  1816 
  1817 * 'hide': option '(open)' hides only base names.
  1818 
  1819 * More efficient treatment of intermediate checkpoints in interactive
  1820 theory development.
  1821 
  1822 * Code generator is now invoked via code_module (incremental code
  1823 generation) and code_library (modular code generation, ML structures
  1824 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1825 must be quoted when used as identifiers.
  1826 
  1827 * New 'value' command for reading, evaluating and printing terms using
  1828 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1829 quoted when used as identifier.
  1830 
  1831 
  1832 *** Locales ***
  1833 
  1834 * New commands for the interpretation of locale expressions in
  1835 theories (1), locales (2) and proof contexts (3).  These generate
  1836 proof obligations from the expression specification.  After the
  1837 obligations have been discharged, theorems of the expression are added
  1838 to the theory, target locale or proof context.  The synopsis of the
  1839 commands is a follows:
  1840 
  1841   (1) interpretation expr inst
  1842   (2) interpretation target < expr
  1843   (3) interpret expr inst
  1844 
  1845 Interpretation in theories and proof contexts require a parameter
  1846 instantiation of terms from the current context.  This is applied to
  1847 specifications and theorems of the interpreted expression.
  1848 Interpretation in locales only permits parameter renaming through the
  1849 locale expression.  Interpretation is smart in that interpretations
  1850 that are active already do not occur in proof obligations, neither are
  1851 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1852 inspect active interpretations of a particular locale.  For details,
  1853 see the Isar Reference manual.  Examples can be found in
  1854 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1855 
  1856 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1857 'interpret' instead.
  1858 
  1859 * New context element 'constrains' for adding type constraints to
  1860 parameters.
  1861 
  1862 * Context expressions: renaming of parameters with syntax
  1863 redeclaration.
  1864 
  1865 * Locale declaration: 'includes' disallowed.
  1866 
  1867 * Proper static binding of attribute syntax -- i.e. types / terms /
  1868 facts mentioned as arguments are always those of the locale definition
  1869 context, independently of the context of later invocations.  Moreover,
  1870 locale operations (renaming and type / term instantiation) are applied
  1871 to attribute arguments as expected.
  1872 
  1873 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1874 actual attributes; rare situations may require Attrib.attribute to
  1875 embed those attributes into Attrib.src that lack concrete syntax.
  1876 Attribute implementations need to cooperate properly with the static
  1877 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1878 Attrib.XXX_thm etc. already do the right thing without further
  1879 intervention.  Only unusual applications -- such as "where" or "of"
  1880 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1881 on the context and the facts involved -- may have to assign parsed
  1882 values to argument tokens explicitly.
  1883 
  1884 * Changed parameter management in theorem generation for long goal
  1885 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1886 theorem statement in rare situations.
  1887 
  1888 * Locale inspection command 'print_locale' omits notes elements.  Use
  1889 'print_locale!' to have them included in the output.
  1890 
  1891 
  1892 *** Provers ***
  1893 
  1894 * Provers/hypsubst.ML: improved version of the subst method, for
  1895 single-step rewriting: it now works in bound variable contexts. New is
  1896 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1897 rewrite a different subterm than the original subst method, which is
  1898 still available as 'simplesubst'.
  1899 
  1900 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1901 and quasi orders.
  1902 
  1903 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1904 reflexive-transitive closure of relations.
  1905 
  1906 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1907 limit (previously hard-coded with a value of 20) user-definable.
  1908 
  1909 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1910 is peformed already.  Object-logics merely need to finish their
  1911 initial simpset configuration as before.  INCOMPATIBILITY.
  1912 
  1913 
  1914 *** HOL ***
  1915 
  1916 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1917 
  1918   syntax (epsilon)
  1919     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1920 
  1921 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1922 and x-symbol; use option '-m epsilon' to get it actually printed.
  1923 Moreover, the mathematically important symbolic identifier \<epsilon>
  1924 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1925 
  1926 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1927 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1928 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1929 support corresponding Isar calculations.
  1930 
  1931 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1932 instead of ":".
  1933 
  1934 * theory SetInterval: changed the syntax for open intervals:
  1935 
  1936   Old       New
  1937   {..n(}    {..<n}
  1938   {)n..}    {n<..}
  1939   {m..n(}   {m..<n}
  1940   {)m..n}   {m<..n}
  1941   {)m..n(}  {m<..<n}
  1942 
  1943 The old syntax is still supported but will disappear in the next
  1944 release.  For conversion use the following Emacs search and replace
  1945 patterns (these are not perfect but work quite well):
  1946 
  1947   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1948   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1949 
  1950 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1951 equalities in commutative rings; method 'algebra' provides a generic
  1952 interface.
  1953 
  1954 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1955 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1956 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1957 be a tuple pattern.
  1958 
  1959 Some new syntax forms are available:
  1960 
  1961   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1962   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1963   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1964   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1965 
  1966 The latter form "\<Sum>x < k. e" used to be based on a separate
  1967 function "Summation", which has been discontinued.
  1968 
  1969 * theory Finite_Set: in structured induction proofs, the insert case
  1970 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1971 (insert F x)'.
  1972 
  1973 * The 'refute' command has been extended to support a much larger
  1974 fragment of HOL, including axiomatic type classes, constdefs and
  1975 typedefs, inductive datatypes and recursion.
  1976 
  1977 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1978 Requires zChaff with proof generation to be installed.  See
  1979 HOL/ex/SAT_Examples.thy for examples.
  1980 
  1981 * Datatype induction via method 'induct' now preserves the name of the
  1982 induction variable. For example, when proving P(xs::'a list) by
  1983 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1984 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1985 in unstructured proof scripts.
  1986 
  1987 * Reworked implementation of records.  Improved scalability for
  1988 records with many fields, avoiding performance problems for type
  1989 inference. Records are no longer composed of nested field types, but
  1990 of nested extension types. Therefore the record type only grows linear
  1991 in the number of extensions and not in the number of fields.  The
  1992 top-level (users) view on records is preserved.  Potential
  1993 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1994 old record representation. The type generated for a record is called
  1995 <record_name>_ext_type.
  1996 
  1997 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1998 proofs triggered by a record definition or a simproc (if
  1999 quick_and_dirty is enabled).  Definitions of large records can take
  2000 quite long.
  2001 
  2002 New simproc record_upd_simproc for simplification of multiple record
  2003 updates enabled by default.  Moreover, trivial updates are also
  2004 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2005 occasionally, since simplification is more powerful by default.
  2006 
  2007 * typedef: proper support for polymorphic sets, which contain extra
  2008 type-variables in the term.
  2009 
  2010 * Simplifier: automatically reasons about transitivity chains
  2011 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2012 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2013 old proofs break occasionally as simplification may now solve more
  2014 goals than previously.
  2015 
  2016 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2017 present.  Works for all partial orders (class "order"), in particular
  2018 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2019 just like y <= x.
  2020 
  2021 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2022 bound variable or a constant then the let is unfolded.  Otherwise
  2023 first a is simplified to b, and then f b is simplified to g. If
  2024 possible we abstract b from g arriving at "let x = b in h x",
  2025 otherwise we unfold the let and arrive at g.  The simproc can be
  2026 enabled/disabled by the reference use_let_simproc.  Potential
  2027 INCOMPATIBILITY since simplification is more powerful by default.
  2028 
  2029 * Classical reasoning: the meson method now accepts theorems as arguments.
  2030 
  2031 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2032 jobs to provide advice on the provability of subgoals.
  2033 
  2034 * Theory OrderedGroup and Ring_and_Field: various additions and
  2035 improvements to faciliate calculations involving equalities and
  2036 inequalities.
  2037 
  2038 The following theorems have been eliminated or modified
  2039 (INCOMPATIBILITY):
  2040 
  2041   abs_eq             now named abs_of_nonneg
  2042   abs_of_ge_0        now named abs_of_nonneg
  2043   abs_minus_eq       now named abs_of_nonpos
  2044   imp_abs_id         now named abs_of_nonneg
  2045   imp_abs_neg_id     now named abs_of_nonpos
  2046   mult_pos           now named mult_pos_pos
  2047   mult_pos_le        now named mult_nonneg_nonneg
  2048   mult_pos_neg_le    now named mult_nonneg_nonpos
  2049   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2050   mult_neg           now named mult_neg_neg
  2051   mult_neg_le        now named mult_nonpos_nonpos
  2052 
  2053 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2054      
  2055      zero_le_square
  2056      not_square_less_zero 
  2057 
  2058   The following lemmas have been deleted from Real/RealPow:
  2059   
  2060      realpow_zero_zero
  2061      realpow_two
  2062      realpow_less
  2063      zero_le_power
  2064      realpow_two_le
  2065      abs_realpow_two
  2066      realpow_two_abs     
  2067 
  2068 * Theory Parity: added rules for simplifying exponents.
  2069 
  2070 * Theory List:
  2071 
  2072 The following theorems have been eliminated or modified
  2073 (INCOMPATIBILITY):
  2074 
  2075   list_all_Nil       now named list_all.simps(1)
  2076   list_all_Cons      now named list_all.simps(2)
  2077   list_all_conv      now named list_all_iff
  2078   set_mem_eq         now named mem_iff
  2079 
  2080 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2081 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2082 
  2083 
  2084 *** HOL-Complex ***
  2085 
  2086 * Theory RealDef: better support for embedding natural numbers and
  2087 integers in the reals.
  2088 
  2089 The following theorems have been eliminated or modified
  2090 (INCOMPATIBILITY):
  2091 
  2092   exp_ge_add_one_self  now requires no hypotheses
  2093   real_of_int_add      reversed direction of equality (use [symmetric])
  2094   real_of_int_minus    reversed direction of equality (use [symmetric])
  2095   real_of_int_diff     reversed direction of equality (use [symmetric])
  2096   real_of_int_mult     reversed direction of equality (use [symmetric])
  2097 
  2098 * Theory RComplete: expanded support for floor and ceiling functions.
  2099 
  2100 * Theory Ln is new, with properties of the natural logarithm
  2101 
  2102 * Hyperreal: There is a new type constructor "star" for making
  2103 nonstandard types.  The old type names are now type synonyms:
  2104 
  2105   hypreal = real star
  2106   hypnat = nat star
  2107   hcomplex = complex star
  2108 
  2109 * Hyperreal: Many groups of similarly-defined constants have been
  2110 replaced by polymorphic versions (INCOMPATIBILITY):
  2111 
  2112   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2113 
  2114   starset      <-- starsetNat, starsetC
  2115   *s*          <-- *sNat*, *sc*
  2116   starset_n    <-- starsetNat_n, starsetC_n
  2117   *sn*         <-- *sNatn*, *scn*
  2118   InternalSets <-- InternalNatSets, InternalCSets
  2119 
  2120   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2121   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2122   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2123   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2124   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2125 
  2126 * Hyperreal: Many type-specific theorems have been removed in favor of
  2127 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2128 
  2129   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2130   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2131   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2132   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2133   right_minus <-- hypreal_add_minus
  2134   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2135   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2136   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2137   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2138   mult_1_right <-- hcomplex_mult_one_right
  2139   mult_zero_left <-- hcomplex_mult_zero_left
  2140   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2141   right_distrib <-- hypnat_add_mult_distrib2
  2142   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2143   right_inverse <-- hypreal_mult_inverse
  2144   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2145   order_refl <-- {hypreal,hypnat}_le_refl
  2146   order_trans <-- {hypreal,hypnat}_le_trans
  2147   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2148   order_less_le <-- {hypreal,hypnat}_less_le
  2149   linorder_linear <-- {hypreal,hypnat}_le_linear
  2150   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2151   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2152   add_nonneg_nonneg <-- hypreal_le_add_order
  2153 
  2154 * Hyperreal: Separate theorems having to do with type-specific
  2155 versions of constants have been merged into theorems that apply to the
  2156 new polymorphic constants (INCOMPATIBILITY):
  2157 
  2158   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2159   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2160   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2161   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2162   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2163   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2164   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2165   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2166   STAR_diff <-- {STAR,STARC}_diff
  2167   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2168     STARC_hcomplex_of_complex}_image_subset
  2169   starset_n_Un <-- starset{Nat,C}_n_Un
  2170   starset_n_Int <-- starset{Nat,C}_n_Int
  2171   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2172   starset_n_diff <-- starset{Nat,C}_n_diff
  2173   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2174   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2175   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2176   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2177   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2178   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2179   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2180   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2181   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2182   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2183   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2184   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2185   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2186   starfun_diff <-- starfun{C,RC,CR}_diff
  2187   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2188   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2189   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2190   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2191   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2192   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2193   starfun_Id <-- starfunC_Id
  2194   starfun_approx <-- starfun{Nat,CR}_approx
  2195   starfun_capprox <-- starfun{C,RC}_capprox
  2196   starfun_abs <-- starfunNat_rabs
  2197   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2198   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2199   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2200   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2201   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2202   starfun_add_approx <-- starfunCR_add_approx
  2203   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2204   starfun_divide <-- starfun{C,CR,RC}_divide
  2205   starfun_n <-- starfun{Nat,C}_n
  2206   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2207   starfun_n_add <-- starfun{Nat,C}_n_add
  2208   starfun_n_add_minus <-- starfunNat_n_add_minus
  2209   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2210   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2211   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2212 
  2213   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2214   star_n_minus <-- {hypreal,hcomplex}_minus
  2215   star_n_diff <-- {hypreal,hcomplex}_diff
  2216   star_n_mult <-- {hypreal,hcomplex}_mult
  2217   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2218   star_n_le <-- {hypreal,hypnat}_le
  2219   star_n_less <-- {hypreal,hypnat}_less
  2220   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2221   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2222   star_n_abs <-- hypreal_hrabs
  2223   star_n_divide <-- hcomplex_divide
  2224 
  2225   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2226   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2227   star_of_diff <-- hypreal_of_real_diff
  2228   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2229   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2230   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2231   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2232   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2233   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2234   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2235   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2236   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2237   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2238   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2239   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2240   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2241   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2242   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2243   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2244   star_of_power <-- hypreal_of_real_power
  2245   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2246 
  2247 * Hyperreal: new method "transfer" that implements the transfer
  2248 principle of nonstandard analysis. With a subgoal that mentions
  2249 nonstandard types like "'a star", the command "apply transfer"
  2250 replaces it with an equivalent one that mentions only standard types.
  2251 To be successful, all free variables must have standard types; non-
  2252 standard variables must have explicit universal quantifiers.
  2253 
  2254 * Hyperreal: A theory of Taylor series.
  2255 
  2256 
  2257 *** HOLCF ***
  2258 
  2259 * Discontinued special version of 'constdefs' (which used to support
  2260 continuous functions) in favor of the general Pure one with full
  2261 type-inference.
  2262 
  2263 * New simplification procedure for solving continuity conditions; it
  2264 is much faster on terms with many nested lambda abstractions (cubic
  2265 instead of exponential time).
  2266 
  2267 * New syntax for domain package: selector names are now optional.
  2268 Parentheses should be omitted unless argument is lazy, for example:
  2269 
  2270   domain 'a stream = cons "'a" (lazy "'a stream")
  2271 
  2272 * New command 'fixrec' for defining recursive functions with pattern
  2273 matching; defining multiple functions with mutual recursion is also
  2274 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2275 sinr, or any data constructor defined by the domain package. The given
  2276 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2277 syntax and examples.
  2278 
  2279 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2280 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2281 but the proof obligation additionally includes an admissibility
  2282 requirement. The packages generate instances of class cpo or pcpo,
  2283 with continuity and strictness theorems for Rep and Abs.
  2284 
  2285 * HOLCF: Many theorems have been renamed according to a more standard naming
  2286 scheme (INCOMPATIBILITY):
  2287 
  2288   foo_inject:  "foo$x = foo$y ==> x = y"
  2289   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2290   foo_less:    "(foo$x << foo$y) = (x << y)"
  2291   foo_strict:  "foo$UU = UU"
  2292   foo_defined: "... ==> foo$x ~= UU"
  2293   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2294 
  2295 
  2296 *** ZF ***
  2297 
  2298 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2299 including the First Isomorphism Theorem (on quotienting by the kernel
  2300 of a homomorphism).
  2301 
  2302 * ZF/Simplifier: install second copy of type solver that actually
  2303 makes use of TC rules declared to Isar proof contexts (or locales);
  2304 the old version is still required for ML proof scripts.
  2305 
  2306 
  2307 *** Cube ***
  2308 
  2309 * Converted to Isar theory format; use locales instead of axiomatic
  2310 theories.
  2311 
  2312 
  2313 *** ML ***
  2314 
  2315 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2316 for ||>, ||>>, |>>,
  2317 
  2318 * Pure/library.ML no longer defines its own option datatype, but uses
  2319 that of the SML basis, which has constructors NONE and SOME instead of
  2320 None and Some, as well as exception Option.Option instead of OPTION.
  2321 The functions the, if_none, is_some, is_none have been adapted
  2322 accordingly, while Option.map replaces apsome.
  2323 
  2324 * Pure/library.ML: the exception LIST has been given up in favour of
  2325 the standard exceptions Empty and Subscript, as well as
  2326 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2327 superceded by the standard hd and tl functions etc.
  2328 
  2329 A number of basic list functions are no longer exported to the ML
  2330 toplevel, as they are variants of predefined functions.  The following
  2331 suggests how one can translate existing code:
  2332 
  2333     rev_append xs ys = List.revAppend (xs, ys)
  2334     nth_elem (i, xs) = List.nth (xs, i)
  2335     last_elem xs = List.last xs
  2336     flat xss = List.concat xss
  2337     seq fs = List.app fs
  2338     partition P xs = List.partition P xs
  2339     mapfilter f xs = List.mapPartial f xs
  2340 
  2341 * Pure/library.ML: several combinators for linear functional
  2342 transformations, notably reverse application and composition:
  2343 
  2344   x |> f                f #> g
  2345   (x, y) |-> f          f #-> g
  2346 
  2347 * Pure/library.ML: introduced/changed precedence of infix operators:
  2348 
  2349   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2350   infix 2 ?;
  2351   infix 3 o oo ooo oooo;
  2352   infix 4 ~~ upto downto;
  2353 
  2354 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2355 infix operators.
  2356 
  2357 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2358 fold_map support linear functional transformations and nesting.  For
  2359 example:
  2360 
  2361   fold f [x1, ..., xN] y =
  2362     y |> f x1 |> ... |> f xN
  2363 
  2364   (fold o fold) f [xs1, ..., xsN] y =
  2365     y |> fold f xs1 |> ... |> fold f xsN
  2366 
  2367   fold f [x1, ..., xN] =
  2368     f x1 #> ... #> f xN
  2369 
  2370   (fold o fold) f [xs1, ..., xsN] =
  2371     fold f xs1 #> ... #> fold f xsN
  2372 
  2373 * Pure/library.ML: the following selectors on type 'a option are
  2374 available:
  2375 
  2376   the:               'a option -> 'a  (*partial*)
  2377   these:             'a option -> 'a  where 'a = 'b list
  2378   the_default: 'a -> 'a option -> 'a
  2379   the_list:          'a option -> 'a list
  2380 
  2381 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2382 basic operations for association lists, following natural argument
  2383 order; moreover the explicit equality predicate passed here avoids
  2384 potentially expensive polymorphic runtime equality checks.
  2385 The old functions may be expressed as follows:
  2386 
  2387   assoc = uncurry (AList.lookup (op =))
  2388   assocs = these oo AList.lookup (op =)
  2389   overwrite = uncurry (AList.update (op =)) o swap
  2390 
  2391 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2392 
  2393   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2394   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2395 
  2396 replacing make_keylist and keyfilter (occassionally used)
  2397 Naive rewrites:
  2398 
  2399   make_keylist = AList.make
  2400   keyfilter = AList.find (op =)
  2401 
  2402 * eq_fst and eq_snd now take explicit equality parameter, thus
  2403   avoiding eqtypes. Naive rewrites:
  2404 
  2405     eq_fst = eq_fst (op =)
  2406     eq_snd = eq_snd (op =)
  2407 
  2408 * Removed deprecated apl and apr (rarely used).
  2409   Naive rewrites:
  2410 
  2411     apl (n, op) =>>= curry op n
  2412     apr (op, m) =>>= fn n => op (n, m)
  2413 
  2414 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2415 provides a reasonably efficient light-weight implementation of sets as
  2416 lists.
  2417 
  2418 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2419 few new operations; existing lookup and update are now curried to
  2420 follow natural argument order (for use with fold etc.);
  2421 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2422 
  2423 * Pure/General: output via the Isabelle channels of
  2424 writeln/warning/error etc. is now passed through Output.output, with a
  2425 hook for arbitrary transformations depending on the print_mode
  2426 (cf. Output.add_mode -- the first active mode that provides a output
  2427 function wins).  Already formatted output may be embedded into further
  2428 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2429 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2430 accommodate easy composition of diagnostic messages etc.  Programmers
  2431 rarely need to care about Output.output or Output.raw at all, with
  2432 some notable exceptions: Output.output is required when bypassing the
  2433 standard channels (writeln etc.), or in token translations to produce
  2434 properly formatted results; Output.raw is required when capturing
  2435 already output material that will eventually be presented to the user
  2436 a second time.  For the default print mode, both Output.output and
  2437 Output.raw have no effect.
  2438 
  2439 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2440 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2441 cumulative results are displayed at the end of a batch session.
  2442 
  2443 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2444 replaced by File.platform_path and File.shell_path (with appropriate
  2445 hooks).  This provides a clean interface for unusual systems where the
  2446 internal and external process view of file names are different.
  2447 
  2448 * Pure: more efficient orders for basic syntactic entities: added
  2449 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2450 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2451 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2452 orders now -- potential INCOMPATIBILITY for code that depends on a
  2453 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2454 Library.sort_strings on result).
  2455 
  2456 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2457 fold_types traverse types/terms from left to right, observing natural
  2458 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2459 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2460 
  2461 * Pure: name spaces have been refined, with significant changes of the
  2462 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2463 to extern(_table).  The plain name entry path is superceded by a
  2464 general 'naming' context, which also includes the 'policy' to produce
  2465 a fully qualified name and external accesses of a fully qualified
  2466 name; NameSpace.extend is superceded by context dependent
  2467 Sign.declare_name.  Several theory and proof context operations modify
  2468 the naming context.  Especially note Theory.restore_naming and
  2469 ProofContext.restore_naming to get back to a sane state; note that
  2470 Theory.add_path is no longer sufficient to recover from
  2471 Theory.absolute_path in particular.
  2472 
  2473 * Pure: new flags short_names (default false) and unique_names
  2474 (default true) for controlling output of qualified names.  If
  2475 short_names is set, names are printed unqualified.  If unique_names is
  2476 reset, the name prefix is reduced to the minimum required to achieve
  2477 the original result when interning again, even if there is an overlap
  2478 with earlier declarations.
  2479 
  2480 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2481 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2482 (useful for printing error messages).  INCOMPATIBILITY.
  2483 
  2484 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2485 Theory.theory are now identified, referring to the universal
  2486 Context.theory (see Pure/context.ML).  Actual signature and theory
  2487 content is managed as theory data.  The old code and interfaces were
  2488 spread over many files and structures; the new arrangement introduces
  2489 considerable INCOMPATIBILITY to gain more clarity:
  2490 
  2491   Context -- theory management operations (name, identity, inclusion,
  2492     parents, ancestors, merge, etc.), plus generic theory data;
  2493 
  2494   Sign -- logical signature and syntax operations (declaring consts,
  2495     types, etc.), plus certify/read for common entities;
  2496 
  2497   Theory -- logical theory operations (stating axioms, definitions,
  2498     oracles), plus a copy of logical signature operations (consts,
  2499     types, etc.); also a few basic management operations (Theory.copy,
  2500     Theory.merge, etc.)
  2501 
  2502 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2503 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2504 for convenience -- they merely return the theory.
  2505 
  2506 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2507 
  2508 * Pure: the Isar proof context type is already defined early in Pure
  2509 as Context.proof (note that ProofContext.context and Proof.context are
  2510 aliases, where the latter is the preferred name).  This enables other
  2511 Isabelle components to refer to that type even before Isar is present.
  2512 
  2513 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2514 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2515 any of these kinds.  For example, Sign.intern typeK is now
  2516 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2517 Theory.hide_types.  Also note that former
  2518 Theory.hide_classes/types/consts are now
  2519 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2520 internalize their arguments!  INCOMPATIBILITY.
  2521 
  2522 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2523 datatype thmref (with constructors Name and NameSelection) instead of
  2524 plain string -- INCOMPATIBILITY;
  2525 
  2526 * Pure: cases produced by proof methods specify options, where NONE
  2527 means to remove case bindings -- INCOMPATIBILITY in
  2528 (RAW_)METHOD_CASES.
  2529 
  2530 * Pure: the following operations retrieve axioms or theorems from a
  2531 theory node or theory hierarchy, respectively:
  2532 
  2533   Theory.axioms_of: theory -> (string * term) list
  2534   Theory.all_axioms_of: theory -> (string * term) list
  2535   PureThy.thms_of: theory -> (string * thm) list
  2536   PureThy.all_thms_of: theory -> (string * thm) list
  2537 
  2538 * Pure: print_tac now outputs the goal through the trace channel.
  2539 
  2540 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2541 Reference Toplevel.debug (default false) controls detailed printing
  2542 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2543 controls execution profiling -- set to 1 for time and 2 for space
  2544 (both increase the runtime).
  2545 
  2546 * Isar session: The initial use of ROOT.ML is now always timed,
  2547 i.e. the log will show the actual process times, in contrast to the
  2548 elapsed wall-clock time that the outer shell wrapper produces.
  2549 
  2550 * Simplifier: improved handling of bound variables (nameless
  2551 representation, avoid allocating new strings).  Simprocs that invoke
  2552 the Simplifier recursively should use Simplifier.inherit_bounds to
  2553 avoid local name clashes.  Failure to do so produces warnings
  2554 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2555 for further details.
  2556 
  2557 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2558 bindings for all theorems stored within a given theory; this may help
  2559 in porting non-Isar theories to Isar ones, while keeping ML proof
  2560 scripts for the time being.
  2561 
  2562 * ML operator HTML.with_charset specifies the charset begin used for
  2563 generated HTML files.  For example:
  2564 
  2565   HTML.with_charset "utf-8" use_thy "Hebrew";
  2566   HTML.with_charset "utf-8" use_thy "Chinese";
  2567 
  2568 
  2569 *** System ***
  2570 
  2571 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2572 isabelle, isatool etc.).
  2573 
  2574 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2575 isatool doc, isatool mkdir, display_drafts etc.).
  2576 
  2577 * isatool usedir: option -f allows specification of the ML file to be
  2578 used by Isabelle; default is ROOT.ML.
  2579 
  2580 * New isatool version outputs the version identifier of the Isabelle
  2581 distribution being used.
  2582 
  2583 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2584 (containing Boolean satisfiability problems) into Isabelle/HOL
  2585 theories.
  2586 
  2587 
  2588 
  2589 New in Isabelle2004 (April 2004)
  2590 --------------------------------
  2591 
  2592 *** General ***
  2593 
  2594 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2595   Replaces linorder.ML.
  2596 
  2597 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2598   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2599   (\<a>...\<z>), are now considered normal letters, and can therefore
  2600   be used anywhere where an ASCII letter (a...zA...Z) has until
  2601   now. COMPATIBILITY: This obviously changes the parsing of some
  2602   terms, especially where a symbol has been used as a binder, say
  2603   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2604   as an identifier.  Fix it by inserting a space around former
  2605   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2606   existing theory and ML files.
  2607 
  2608 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2609 
  2610 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2611   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2612   a normal (but invisible) letter. For multiple letter subscripts repeat
  2613   \<^isub> like this: x\<^isub>1\<^isub>2.
  2614 
  2615 * Pure: There are now sub-/superscripts that can span more than one
  2616   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2617   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2618   superscript. The new control characters are not identifier parts.
  2619 
  2620 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2621   content of "..." to the latex file instead of \isacntrl... . The "..."
  2622   may consist of any printable characters excluding the end bracket >.
  2623 
  2624 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2625   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2626   declare constants "final", which prevents their being given a definition
  2627   later.  It is useful for constants whose behaviour is fixed axiomatically
  2628   rather than definitionally, such as the meta-logic connectives.
  2629 
  2630 * Pure: 'instance' now handles general arities with general sorts
  2631   (i.e. intersections of classes),
  2632 
  2633 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2634   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2635   It can be changed to alter the colors/layout of generated pages.
  2636 
  2637 
  2638 *** Isar ***
  2639 
  2640 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2641   cut_tac, subgoal_tac and thin_tac:
  2642   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2643     locales are no longer forced to write Isar proof scripts.
  2644     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2645     emulations.
  2646   - INCOMPATIBILITY: names of variables to be instantiated may no
  2647     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2648     This is consistent with the instantiation attribute "where".
  2649 
  2650 * Attributes "where" and "of":
  2651   - Now take type variables of instantiated theorem into account when reading
  2652     the instantiation string.  This fixes a bug that caused instantiated
  2653     theorems to have too special types in some circumstances.
  2654   - "where" permits explicit instantiations of type variables.
  2655 
  2656 * Calculation commands "moreover" and "also" no longer interfere with
  2657   current facts ("this"), admitting arbitrary combinations with "then"
  2658   and derived forms.
  2659 
  2660 * Locales:
  2661   - Goal statements involving the context element "includes" no longer
  2662     generate theorems with internal delta predicates (those ending on
  2663     "_axioms") in the premise.
  2664     Resolve particular premise with <locale>.intro to obtain old form.
  2665   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2666     specification and "includes" elements in goal statement.
  2667   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2668     [intro?] and [elim?] (respectively) by default.
  2669   - Experimental command for instantiation of locales in proof contexts:
  2670         instantiate <label>[<attrs>]: <loc>
  2671     Instantiates locale <loc> and adds all its theorems to the current context
  2672     taking into account their attributes.  Label and attrs are optional
  2673     modifiers, like in theorem declarations.  If present, names of
  2674     instantiated theorems are qualified with <label>, and the attributes
  2675     <attrs> are applied after any attributes these theorems might have already.
  2676       If the locale has assumptions, a chained fact of the form
  2677     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2678     are derived.  The command does not support old-style locales declared
  2679     with "locale (open)".
  2680       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2681 
  2682 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2683   (Isar) contexts.
  2684 
  2685 
  2686 *** HOL ***
  2687 
  2688 * Proof import: new image HOL4 contains the imported library from
  2689   the HOL4 system with about 2500 theorems. It is imported by
  2690   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2691   can be used like any other Isabelle image.  See
  2692   HOL/Import/HOL/README for more information.
  2693 
  2694 * Simplifier:
  2695   - Much improved handling of linear and partial orders.
  2696     Reasoners for linear and partial orders are set up for type classes
  2697     "linorder" and "order" respectively, and are added to the default simpset
  2698     as solvers.  This means that the simplifier can build transitivity chains
  2699     to solve goals from the assumptions.
  2700   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2701     of blast or auto after simplification become unnecessary because the goal
  2702     is solved by simplification already.
  2703 
  2704 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2705     all proved in axiomatic type classes for semirings, rings and fields.
  2706 
  2707 * Numerics:
  2708   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2709     now formalized using the Ring_and_Field theory mentioned above.
  2710   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2711     than before, because now they are set up once in a generic manner.
  2712   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2713     Look for the general versions in Ring_and_Field (and Power if they concern
  2714     exponentiation).
  2715 
  2716 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2717 
  2718 * Records:
  2719   - Record types are now by default printed with their type abbreviation
  2720     instead of the list of all field types. This can be configured via
  2721     the reference "print_record_type_abbr".
  2722   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2723     (not enabled by default).
  2724   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2725     EX x. x = sel r to True (not enabled by default).
  2726   - Tactic "record_split_simp_tac" to split and simplify records added.
  2727 
  2728 * 'specification' command added, allowing for definition by
  2729   specification.  There is also an 'ax_specification' command that
  2730   introduces the new constants axiomatically.
  2731 
  2732 * arith(_tac) is now able to generate counterexamples for reals as well.
  2733 
  2734 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2735 
  2736 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2737   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2738 
  2739 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2740   matrix theory to linear programming.
  2741 
  2742 * Unions and Intersections:
  2743   The latex output syntax of UN and INT has been changed
  2744   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2745   i.e. the index formulae has become a subscript.
  2746   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2747 
  2748 * Unions and Intersections over Intervals:
  2749   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2750   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2751   like in normal math, and corresponding versions for < and for intersection.
  2752 
  2753 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2754   lexicographic dictonary ordering has been added as "lexord".
  2755 
  2756 * ML: the legacy theory structures Int and List have been removed. They had
  2757   conflicted with ML Basis Library structures having the same names.
  2758 
  2759 * 'refute' command added to search for (finite) countermodels.  Only works
  2760   for a fragment of HOL.  The installation of an external SAT solver is
  2761   highly recommended.  See "HOL/Refute.thy" for details.
  2762 
  2763 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2764   formulae under an assignment of free variables to random values.
  2765   In contrast to 'refute', it can deal with inductive datatypes,
  2766   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2767   for examples.
  2768 
  2769 
  2770 *** HOLCF ***
  2771 
  2772 * Streams now come with concatenation and are part of the HOLCF image
  2773 
  2774 
  2775 
  2776 New in Isabelle2003 (May 2003)
  2777 ------------------------------
  2778 
  2779 *** General ***
  2780 
  2781 * Provers/simplifier:
  2782 
  2783   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2784     Assumptions are now subject to complete mutual simplification,
  2785     not just from left to right. The simplifier now preserves
  2786     the order of assumptions.
  2787 
  2788     Potential INCOMPATIBILITY:
  2789 
  2790     -- simp sometimes diverges where the old version did
  2791        not, e.g. invoking simp on the goal
  2792 
  2793         [| P (f x); y = x; f x = f y |] ==> Q
  2794 
  2795        now gives rise to the infinite reduction sequence
  2796 
  2797         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2798 
  2799        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2800        kind of problem.
  2801 
  2802     -- Tactics combining classical reasoner and simplification (such as auto)
  2803        are also affected by this change, because many of them rely on
  2804        simp. They may sometimes diverge as well or yield a different numbers
  2805        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2806        in case of problems. Sometimes subsequent calls to the classical
  2807        reasoner will fail because a preceeding call to the simplifier too
  2808        eagerly simplified the goal, e.g. deleted redundant premises.
  2809 
  2810   - The simplifier trace now shows the names of the applied rewrite rules
  2811 
  2812   - You can limit the number of recursive invocations of the simplifier
  2813     during conditional rewriting (where the simplifie tries to solve the
  2814     conditions before applying the rewrite rule):
  2815     ML "simp_depth_limit := n"
  2816     where n is an integer. Thus you can force termination where previously
  2817     the simplifier would diverge.
  2818 
  2819   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2820 
  2821   - No longer aborts on failed congruence proof.  Instead, the
  2822     congruence is ignored.
  2823 
  2824 * Pure: New generic framework for extracting programs from constructive
  2825   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2826   as HOL/Extraction for some case studies.
  2827 
  2828 * Pure: The main goal of the proof state is no longer shown by default, only
  2829 the subgoals. This behaviour is controlled by a new flag.
  2830    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2831 (ML: Proof.show_main_goal).
  2832 
  2833 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2834 rules whose conclusion matches subgoal 1:
  2835       PG menu: Isabelle/Isar -> Show me -> matching rules
  2836 The rules are ordered by how closely they match the subgoal.
  2837 In particular, rules that solve a subgoal outright are displayed first
  2838 (or rather last, the way they are printed).
  2839 (ML: ProofGeneral.print_intros())
  2840 
  2841 * Pure: New flag trace_unify_fail causes unification to print
  2842 diagnostic information (PG: in trace buffer) when it fails. This is
  2843 useful for figuring out why single step proofs like rule, erule or
  2844 assumption failed.
  2845 
  2846 * Pure: Locale specifications now produce predicate definitions
  2847 according to the body of text (covering assumptions modulo local
  2848 definitions); predicate "loc_axioms" covers newly introduced text,
  2849 while "loc" is cumulative wrt. all included locale expressions; the
  2850 latter view is presented only on export into the global theory
  2851 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2852 on the old view without predicates;
  2853 
  2854 * Pure: predefined locales "var" and "struct" are useful for sharing
  2855 parameters (as in CASL, for example); just specify something like
  2856 ``var x + var y + struct M'' as import;
  2857 
  2858 * Pure: improved thms_containing: proper indexing of facts instead of
  2859 raw theorems; check validity of results wrt. current name space;
  2860 include local facts of proof configuration (also covers active
  2861 locales), cover fixed variables in index; may use "_" in term
  2862 specification; an optional limit for the number of printed facts may
  2863 be given (the default is 40);
  2864 
  2865 * Pure: disallow duplicate fact bindings within new-style theory files
  2866 (batch-mode only);
  2867 
  2868 * Provers: improved induct method: assumptions introduced by case
  2869 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2870 the goal statement); "foo" still refers to all facts collectively;
  2871 
  2872 * Provers: the function blast.overloaded has been removed: all constants
  2873 are regarded as potentially overloaded, which improves robustness in exchange
  2874 for slight decrease in efficiency;
  2875 
  2876 * Provers/linorder: New generic prover for transitivity reasoning over
  2877 linear orders.  Note: this prover is not efficient!
  2878 
  2879 * Isar: preview of problems to finish 'show' now produce an error
  2880 rather than just a warning (in interactive mode);
  2881 
  2882 
  2883 *** HOL ***
  2884 
  2885 * arith(_tac)
  2886 
  2887  - Produces a counter example if it cannot prove a goal.
  2888    Note that the counter example may be spurious if the goal is not a formula
  2889    of quantifier-free linear arithmetic.
  2890    In ProofGeneral the counter example appears in the trace buffer.
  2891 
  2892  - Knows about div k and mod k where k is a numeral of type nat or int.
  2893 
  2894  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2895    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2896    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2897 
  2898 * simp's arithmetic capabilities have been enhanced a bit: it now
  2899 takes ~= in premises into account (by performing a case split);
  2900 
  2901 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2902 are distributed over a sum of terms;
  2903 
  2904 * New tactic "trans_tac" and method "trans" instantiate
  2905 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2906 "<=", "<" and "=").
  2907 
  2908 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2909 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2910 
  2911 * 'typedef' command has new option "open" to suppress the set
  2912 definition;
  2913 
  2914 * functions Min and Max on finite sets have been introduced (theory
  2915 Finite_Set);
  2916 
  2917 * attribute [symmetric] now works for relations as well; it turns
  2918 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2919 
  2920 * induct over a !!-quantified statement (say !!x1..xn):
  2921   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2922 
  2923 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2924 %x. None. Warning: empty_def now refers to the previously hidden definition
  2925 of the empty set.
  2926 
  2927 * Algebra: formalization of classical algebra.  Intended as base for
  2928 any algebraic development in Isabelle.  Currently covers group theory
  2929 (up to Sylow's theorem) and ring theory (Universal Property of
  2930 Univariate Polynomials).  Contributions welcome;
  2931 
  2932 * GroupTheory: deleted, since its material has been moved to Algebra;
  2933 
  2934 * Complex: new directory of the complex numbers with numeric constants,
  2935 nonstandard complex numbers, and some complex analysis, standard and
  2936 nonstandard (Jacques Fleuriot);
  2937 
  2938 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2939 
  2940 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2941 Fleuriot);
  2942 
  2943 * Real/HahnBanach: updated and adapted to locales;
  2944 
  2945 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2946 Gray and Kramer);
  2947 
  2948 * UNITY: added the Meier-Sanders theory of progress sets;
  2949 
  2950 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2951 as abstract algorithms, instantiated to the JVM;
  2952 
  2953 * Bali: Java source language formalization. Type system, operational
  2954 semantics, axiomatic semantics. Supported language features:
  2955 classes, interfaces, objects,virtual methods, static methods,
  2956 static/instance fields, arrays, access modifiers, definite
  2957 assignment, exceptions.
  2958 
  2959 
  2960 *** ZF ***
  2961 
  2962 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2963 universe, etc.);
  2964 
  2965 * Main ZF: virtually all theories converted to new-style format;
  2966 
  2967 
  2968 *** ML ***
  2969 
  2970 * Pure: Tactic.prove provides sane interface for internal proofs;
  2971 omits the infamous "standard" operation, so this is more appropriate
  2972 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2973 
  2974 * Pure: improved error reporting of simprocs;
  2975 
  2976 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2977 up simprocs;
  2978 
  2979 
  2980 *** Document preparation ***
  2981 
  2982 * uses \par instead of \\ for line breaks in theory text. This may
  2983 shift some page breaks in large documents. To get the old behaviour
  2984 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2985 
  2986 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2987 other packages
  2988 
  2989 * \<euro> now needs package babel/greek instead of marvosym (which
  2990 broke \Rightarrow)
  2991 
  2992 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2993 textcomp package)
  2994 
  2995 
  2996 
  2997 New in Isabelle2002 (March 2002)
  2998 --------------------------------
  2999 
  3000 *** Document preparation ***
  3001 
  3002 * greatly simplified document preparation setup, including more
  3003 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3004 instructive isatool mkdir; users should basically be able to get
  3005 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3006 users may run a separate document processing stage manually like this:
  3007 "isatool usedir -D output HOL Test && isatool document Test/output";
  3008 
  3009 * theory dependency graph may now be incorporated into documents;
  3010 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3011 with \includegraphics of LaTeX;
  3012 
  3013 * proper spacing of consecutive markup elements, especially text
  3014 blocks after section headings;
  3015 
  3016 * support bold style (for single symbols only), input syntax is like
  3017 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3018 
  3019 * \<bullet> is now output as bold \cdot by default, which looks much
  3020 better in printed text;
  3021 
  3022 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3023 note that these symbols are currently unavailable in Proof General /
  3024 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3025 
  3026 * isatool latex no longer depends on changed TEXINPUTS, instead
  3027 isatool document copies the Isabelle style files to the target
  3028 location;
  3029 
  3030 
  3031 *** Isar ***
  3032 
  3033 * Pure/Provers: improved proof by cases and induction;
  3034   - 'case' command admits impromptu naming of parameters (such as
  3035     "case (Suc n)");
  3036   - 'induct' method divinates rule instantiation from the inductive
  3037     claim; no longer requires excessive ?P bindings for proper
  3038     instantiation of cases;
  3039   - 'induct' method properly enumerates all possibilities of set/type
  3040     rules; as a consequence facts may be also passed through *type*
  3041     rules without further ado;
  3042   - 'induct' method now derives symbolic cases from the *rulified*
  3043     rule (before it used to rulify cases stemming from the internal
  3044     atomized version); this means that the context of a non-atomic
  3045     statement becomes is included in the hypothesis, avoiding the
  3046     slightly cumbersome show "PROP ?case" form;
  3047   - 'induct' may now use elim-style induction rules without chaining
  3048     facts, using ``missing'' premises from the goal state; this allows
  3049     rules stemming from inductive sets to be applied in unstructured
  3050     scripts, while still benefitting from proper handling of non-atomic
  3051     statements; NB: major inductive premises need to be put first, all
  3052     the rest of the goal is passed through the induction;
  3053   - 'induct' proper support for mutual induction involving non-atomic
  3054     rule statements (uses the new concept of simultaneous goals, see
  3055     below);
  3056   - append all possible rule selections, but only use the first
  3057     success (no backtracking);
  3058   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3059   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3060   - added 'print_induct_rules' (covered by help item in recent Proof
  3061     General versions);
  3062   - moved induct/cases attributes to Pure, methods to Provers;
  3063   - generic method setup instantiated for FOL and HOL;
  3064 
  3065 * Pure: support multiple simultaneous goal statements, for example
  3066 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3067 meta-level mechanism, this acts as if several individual goals had
  3068 been stated separately; in particular common proof methods need to be
  3069 repeated in order to cover all claims; note that a single elimination
  3070 step is *not* sufficient to establish the two conjunctions, so this
  3071 fails:
  3072 
  3073   assume "A & B" then have A and B ..   (*".." fails*)
  3074 
  3075 better use "obtain" in situations as above; alternative refer to
  3076 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3077 
  3078 * Pure: proper integration with ``locales''; unlike the original
  3079 version by Florian Kammller, Isar locales package high-level proof
  3080 contexts rather than raw logical ones (e.g. we admit to include
  3081 attributes everywhere); operations on locales include merge and
  3082 rename; support for implicit arguments (``structures''); simultaneous
  3083 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3084 some examples;
  3085 
  3086 * Pure: the following commands have been ``localized'', supporting a
  3087 target locale specification "(in name)": 'lemma', 'theorem',
  3088 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3089 stored both within the locale and at the theory level (exported and
  3090 qualified by the locale name);
  3091 
  3092 * Pure: theory goals may now be specified in ``long'' form, with
  3093 ad-hoc contexts consisting of arbitrary locale elements. for example
  3094 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3095 definitions may be given, too); the result is a meta-level rule with
  3096 the context elements being discharged in the obvious way;
  3097 
  3098 * Pure: new proof command 'using' allows to augment currently used
  3099 facts after a goal statement ('using' is syntactically analogous to
  3100 'apply', but acts on the goal's facts only); this allows chained facts
  3101 to be separated into parts given before and after a claim, as in
  3102 ``from a and b have C using d and e <proof>'';
  3103 
  3104 * Pure: renamed "antecedent" case to "rule_context";
  3105 
  3106 * Pure: new 'judgment' command records explicit information about the
  3107 object-logic embedding (used by several tools internally); no longer
  3108 use hard-wired "Trueprop";
  3109 
  3110 * Pure: added 'corollary' command;
  3111 
  3112 * Pure: fixed 'token_translation' command;
  3113 
  3114 * Pure: removed obsolete 'exported' attribute;
  3115 
  3116 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3117 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3118 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3119 
  3120 * Pure: method 'atomize' presents local goal premises as object-level
  3121 statements (atomic meta-level propositions); setup controlled via
  3122 rewrite rules declarations of 'atomize' attribute; example
  3123 application: 'induct' method with proper rule statements in improper
  3124 proof *scripts*;
  3125 
  3126 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3127 now consider the syntactic context of assumptions, giving a better
  3128 chance to get type-inference of the arguments right (this is
  3129 especially important for locales);
  3130 
  3131 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3132 mode;
  3133 
  3134 * Pure/obtain: the formal conclusion "thesis", being marked as
  3135 ``internal'', may no longer be reference directly in the text;
  3136 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3137 situations;
  3138 
  3139 * Pure: generic 'sym' attribute which declares a rule both as pure
  3140 'elim?' and for the 'symmetric' operation;
  3141 
  3142 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3143 text; the fixed correlation with particular command syntax has been
  3144 discontinued;
  3145 
  3146 * Pure: new method 'rules' is particularly well-suited for proof
  3147 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3148 but often produces more compact proof terms with less detours;
  3149 
  3150 * Pure/Provers/classical: simplified integration with pure rule
  3151 attributes and methods; the classical "intro?/elim?/dest?"
  3152 declarations coincide with the pure ones; the "rule" method no longer
  3153 includes classically swapped intros; "intro" and "elim" methods no
  3154 longer pick rules from the context; also got rid of ML declarations
  3155 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3156 INCOMPATIBILITY;
  3157 
  3158 * Provers/classical: attribute 'swapped' produces classical inversions
  3159 of introduction rules;
  3160 
  3161 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3162 rules instead of full simplifier context; 'iff' attribute handles
  3163 conditional rules;
  3164 
  3165 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3166 
  3167 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3168 "(permissive)" option to recover old behavior;
  3169 
  3170 * HOL: 'inductive' no longer features separate (collective) attributes
  3171 for 'intros' (was found too confusing);
  3172 
  3173 * HOL: properly declared induction rules less_induct and
  3174 wf_induct_rule;
  3175 
  3176 
  3177 *** HOL ***
  3178 
  3179 * HOL: moved over to sane numeral syntax; the new policy is as
  3180 follows:
  3181 
  3182   - 0 and 1 are polymorphic constants, which are defined on any
  3183   numeric type (nat, int, real etc.);
  3184 
  3185   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3186   binary representation internally;
  3187 
  3188   - type nat has special constructor Suc, and generally prefers Suc 0
  3189   over 1::nat and Suc (Suc 0) over 2::nat;
  3190 
  3191 This change may cause significant problems of INCOMPATIBILITY; here
  3192 are some hints on converting existing sources:
  3193 
  3194   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3195   entities, so expressions involving "-" (unary or binary minus) need
  3196   to be spaced properly;
  3197 
  3198   - existing occurrences of "1" may need to be constraint "1::nat" or
  3199   even replaced by Suc 0; similar for old "2";
  3200 
  3201   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3202 
  3203   - remove all special provisions on numerals in proofs;
  3204 
  3205 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3206 representation (depends on bin_arith_simps in the default context);
  3207 
  3208 * HOL: symbolic syntax for x^2 (numeral 2);
  3209 
  3210 * HOL: the class of all HOL types is now called "type" rather than
  3211 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3212 in axclass/classes, instance/arities, and (usually rare) occurrences
  3213 in typings (of consts etc.); internally the class is called
  3214 "HOL.type", ML programs should refer to HOLogic.typeS;
  3215 
  3216 * HOL/record package improvements:
  3217   - new derived operations "fields" to build a partial record section,
  3218     "extend" to promote a fixed record to a record scheme, and
  3219     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3220     declared as simp by default;
  3221   - shared operations ("more", "fields", etc.) now need to be always
  3222     qualified) --- potential INCOMPATIBILITY;
  3223   - removed "make_scheme" operations (use "make" with "extend") --
  3224     INCOMPATIBILITY;
  3225   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3226   - provides cases/induct rules for use with corresponding Isar
  3227     methods (for concrete records, record schemes, concrete more
  3228     parts, and schematic more parts -- in that order);
  3229   - internal definitions directly based on a light-weight abstract
  3230     theory of product types over typedef rather than datatype;
  3231 
  3232 * HOL: generic code generator for generating executable ML code from
  3233 specifications; specific support for HOL constructs such as inductive
  3234 datatypes and sets, as well as recursive functions; can be invoked
  3235 via 'generate_code' theory section;
  3236 
  3237 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3238 
  3239 * HOL: consolidated and renamed several theories.  In particular:
  3240         Ord.thy has been absorbed into HOL.thy
  3241         String.thy has been absorbed into List.thy
  3242 
  3243 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3244 (beware of argument permutation!);
  3245 
  3246 * HOL: linorder_less_split superseded by linorder_cases;
  3247 
  3248 * HOL/List: "nodups" renamed to "distinct";
  3249 
  3250 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3251 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3252   - Ex_def has changed, now need to use some_eq_ex
  3253 
  3254 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3255 in this (rare) case use:
  3256 
  3257   delSWrapper "split_all_tac"
  3258   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3259 
  3260 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3261 MAY FAIL;
  3262 
  3263 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3264 Isabelle's type classes, ^ on functions and relations has too general
  3265 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3266 necessary to attach explicit type constraints;
  3267 
  3268 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3269 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3270 renamed accordingly (eg "compI" -> "rel_compI").
  3271 
  3272 * HOL: syntax translations now work properly with numerals and records
  3273 expressions;
  3274 
  3275 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3276 of "lam" -- INCOMPATIBILITY;
  3277 
  3278 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3279 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3280 renamed "Product_Type.unit";
  3281 
  3282 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3283 
  3284 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3285 the "cases" method);
  3286 
  3287 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3288 Florian Kammller);
  3289 
  3290 * HOL/IMP: updated and converted to new-style theory format; several
  3291 parts turned into readable document, with proper Isar proof texts and
  3292 some explanations (by Gerwin Klein);
  3293 
  3294 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3295 
  3296 * HOL-Hyperreal is now a logic image;
  3297 
  3298 
  3299 *** HOLCF ***
  3300 
  3301 * Isar: consts/constdefs supports mixfix syntax for continuous
  3302 operations;
  3303 
  3304 * Isar: domain package adapted to new-style theory format, e.g. see
  3305 HOLCF/ex/Dnat.thy;
  3306 
  3307 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3308 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3309 lift.induct_tac, always use UU instead of Undef;
  3310 
  3311 * HOLCF/IMP: updated and converted to new-style theory;
  3312 
  3313 
  3314 *** ZF ***
  3315 
  3316 * Isar: proper integration of logic-specific tools and packages,
  3317 including theory commands '(co)inductive', '(co)datatype',
  3318 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3319 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3320 
  3321 * theory Main no longer includes AC; for the Axiom of Choice, base
  3322 your theory on Main_ZFC;
  3323 
  3324 * the integer library now covers quotients and remainders, with many
  3325 laws relating division to addition, multiplication, etc.;
  3326 
  3327 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3328 typeless version of the formalism;
  3329 
  3330 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3331 format;
  3332 
  3333 * ZF/Induct: new directory for examples of inductive definitions,
  3334 including theory Multiset for multiset orderings; converted to
  3335 new-style theory format;
  3336 
  3337 * ZF: many new theorems about lists, ordinals, etc.;
  3338 
  3339 
  3340 *** General ***
  3341 
  3342 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3343 variable proof controls level of detail: 0 = no proofs (only oracle
  3344 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3345 also ref manual for further ML interfaces;
  3346 
  3347 * Pure/axclass: removed obsolete ML interface
  3348 goal_subclass/goal_arity;
  3349 
  3350 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3351 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3352 separate tokens, so expressions involving minus need to be spaced
  3353 properly;
  3354 
  3355 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3356 rather than "infixl" or "infixr";
  3357 
  3358 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3359 sort constraint specifications in type inference; e.g. "x::_::foo"
  3360 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3361 type variable);
  3362 
  3363 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3364 control output of nested => (types); the default behavior is
  3365 "type_brackets";
  3366 
  3367 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3368 tokens into AST constants;
  3369 
  3370 * Pure/syntax: prefer later declarations of translations and print
  3371 translation functions; potential INCOMPATIBILITY: need to reverse
  3372 multiple declarations for same syntax element constant;
  3373 
  3374 * Pure/show_hyps reset by default (in accordance to existing Isar
  3375 practice);
  3376 
  3377 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3378 addSafter;
  3379 
  3380 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3381 as well;
  3382 
  3383 * system: tested support for MacOS X; should be able to get Isabelle +
  3384 Proof General to work in a plain Terminal after installing Poly/ML
  3385 (e.g. from the Isabelle distribution area) and GNU bash alone
  3386 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3387 support requires further installations, e.g. from
  3388 http://fink.sourceforge.net/);
  3389 
  3390 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3391 
  3392 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3393 of 40 MB), cf. ML_OPTIONS;
  3394 
  3395 * system: Proof General keywords specification is now part of the
  3396 Isabelle distribution (see etc/isar-keywords.el);
  3397 
  3398 * system: support for persistent Proof General sessions (refrain from
  3399 outdating all loaded theories on startup); user may create writable
  3400 logic images like this: ``isabelle -q HOL Test'';
  3401 
  3402 * system: smart selection of Isabelle process versus Isabelle
  3403 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3404 run both "isabelle" and "Isabelle" even if file names are badly
  3405 damaged (executable inspects the case of the first letter of its own
  3406 name); added separate "isabelle-process" and "isabelle-interface";
  3407 
  3408 * system: refrain from any attempt at filtering input streams; no
  3409 longer support ``8bit'' encoding of old isabelle font, instead proper
  3410 iso-latin characters may now be used; the related isatools
  3411 "symbolinput" and "nonascii" have disappeared as well;
  3412 
  3413 * system: removed old "xterm" interface (the print modes "xterm" and
  3414 "xterm_color" are still available for direct use in a suitable
  3415 terminal);
  3416 
  3417 
  3418 
  3419 New in Isabelle99-2 (February 2001)
  3420 -----------------------------------
  3421 
  3422 *** Overview of INCOMPATIBILITIES ***
  3423 
  3424 * HOL: please note that theories in the Library and elsewhere often use the
  3425 new-style (Isar) format; to refer to their theorems in an ML script you must
  3426 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3427 
  3428 * HOL: inductive package no longer splits induction rule aggressively,
  3429 but only as far as specified by the introductions given; the old
  3430 format may be recovered via ML function complete_split_rule or attribute
  3431 'split_rule (complete)';
  3432 
  3433 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3434 gfp_Tarski to gfp_unfold;
  3435 
  3436 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3437 
  3438 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3439 relation); infix "^^" has been renamed "``"; infix "``" has been
  3440 renamed "`"; "univalent" has been renamed "single_valued";
  3441 
  3442 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3443 operation;
  3444 
  3445 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3446 
  3447 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3448 
  3449 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3450 consequence, it is no longer monotonic wrt. the local goal context
  3451 (which is now passed through the inductive cases);
  3452 
  3453 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3454 \<gg> to \<ggreater>;
  3455 
  3456 
  3457 *** Document preparation ***
  3458 
  3459 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3460 available: are "it" for near math-mode best-style output, "sl" for
  3461 slanted text style, and "tt" for plain type-writer; if no
  3462 \isabellestyle command is given, output is according to slanted
  3463 type-writer);
  3464 
  3465 * support sub/super scripts (for single symbols only), input syntax is
  3466 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3467 
  3468 * some more standard symbols; see Appendix A of the system manual for
  3469 the complete list of symbols defined in isabellesym.sty;
  3470 
  3471 * improved isabelle style files; more abstract symbol implementation
  3472 (should now use \isamath{...} and \isatext{...} in custom symbol
  3473 definitions);
  3474 
  3475 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3476 state; Note that presentation of goal states does not conform to
  3477 actual human-readable proof documents.  Please do not include goal
  3478 states into document output unless you really know what you are doing!
  3479 
  3480 * proper indentation of antiquoted output with proportional LaTeX
  3481 fonts;
  3482 
  3483 * no_document ML operator temporarily disables LaTeX document
  3484 generation;
  3485 
  3486 * isatool unsymbolize tunes sources for plain ASCII communication;
  3487 
  3488 
  3489 *** Isar ***
  3490 
  3491 * Pure: Isar now suffers initial goal statements to contain unbound
  3492 schematic variables (this does not conform to actual readable proof
  3493 documents, due to unpredictable outcome and non-compositional proof
  3494 checking); users who know what they are doing may use schematic goals
  3495 for Prolog-style synthesis of proven results;
  3496 
  3497 * Pure: assumption method (an implicit finishing) now handles actual
  3498 rules as well;
  3499 
  3500 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3501 initial goal, declare "that" only as Pure intro (only for single
  3502 steps); the "that" rule assumption may now be involved in implicit
  3503 finishing, thus ".." becomes a feasible for trivial obtains;
  3504 
  3505 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3506 instance proofs may be performed by "..";
  3507 
  3508 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3509 statements as well;
  3510 
  3511 * Pure: more robust selection of calculational rules;
  3512 
  3513 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3514 rule (as well as the assumption rule);
  3515 
  3516 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3517 lemmas, using the graph browser tool;
  3518 
  3519 * Pure: predict failure of "show" in interactive mode;
  3520 
  3521 * Pure: 'thms_containing' now takes actual terms as arguments;
  3522 
  3523 * HOL: improved method 'induct' --- now handles non-atomic goals
  3524 (potential INCOMPATIBILITY); tuned error handling;
  3525 
  3526 * HOL: cases and induct rules now provide explicit hints about the
  3527 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3528 any remaining facts are inserted into the goal verbatim;
  3529 
  3530 * HOL: local contexts (aka cases) may now contain term bindings as
  3531 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3532 the result to be shown in each case;
  3533 
  3534 * HOL: added 'recdef_tc' command;
  3535 
  3536 * isatool convert assists in eliminating legacy ML scripts;
  3537 
  3538 
  3539 *** HOL ***
  3540 
  3541 * HOL/Library: a collection of generic theories to be used together
  3542 with main HOL; the theory loader path already includes this directory
  3543 by default; the following existing theories have been moved here:
  3544 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3545 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3546 
  3547 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3548 modelling and verification task performed in Isabelle/HOL +
  3549 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3550 
  3551 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3552 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3553 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3554 'domain', this makes the theory consistent with mathematical
  3555 literature;
  3556 
  3557 * HOL basics: added overloaded operations "inverse" and "divide"
  3558 (infix "/"), syntax for generic "abs" operation, generic summation
  3559 operator \<Sum>;
  3560 
  3561 * HOL/typedef: simplified package, provide more useful rules (see also
  3562 HOL/subset.thy);
  3563 
  3564 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3565 now expressed as a proper nested rule (old-style tactic scripts may
  3566 require atomize_strip_tac to cope with non-atomic premises);
  3567 
  3568 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3569 to "split_conv" (old name still available for compatibility);
  3570 
  3571 * HOL: improved concrete syntax for strings (e.g. allows translation
  3572 rules with string literals);
  3573 
  3574 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3575  and Fleuriot's mechanization of analysis, including the transcendental
  3576  functions for the reals;
  3577 
  3578 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3579 
  3580 
  3581 *** CTT ***
  3582 
  3583 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3584 "lam" is displayed as TWO lambda-symbols
  3585 
  3586 * CTT: theory Main now available, containing everything (that is, Bool
  3587 and Arith);
  3588 
  3589 
  3590 *** General ***
  3591 
  3592 * Pure: the Simplifier has been implemented properly as a derived rule
  3593 outside of the actual kernel (at last!); the overall performance
  3594 penalty in practical applications is about 50%, while reliability of
  3595 the Isabelle inference kernel has been greatly improved;
  3596 
  3597 * print modes "brackets" and "no_brackets" control output of nested =>
  3598 (types) and ==> (props); the default behaviour is "brackets";
  3599 
  3600 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3601 as assumptions as well;
  3602 
  3603 * system: support Poly/ML 4.0;
  3604 
  3605 * system: isatool install handles KDE version 1 or 2;
  3606 
  3607 
  3608 
  3609 New in Isabelle99-1 (October 2000)
  3610 ----------------------------------
  3611 
  3612 *** Overview of INCOMPATIBILITIES ***
  3613 
  3614 * HOL: simplification of natural numbers is much changed; to partly
  3615 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3616 issue the following ML commands:
  3617 
  3618   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3619   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3620 
  3621 * HOL: simplification no longer dives into case-expressions; this is
  3622 controlled by "t.weak_case_cong" for each datatype t;
  3623 
  3624 * HOL: nat_less_induct renamed to less_induct;
  3625 
  3626 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3627 fixsome to patch .thy and .ML sources automatically;
  3628 
  3629   select_equality  -> some_equality
  3630   select_eq_Ex     -> some_eq_ex
  3631   selectI2EX       -> someI2_ex
  3632   selectI2         -> someI2
  3633   selectI          -> someI
  3634   select1_equality -> some1_equality
  3635   Eps_sym_eq       -> some_sym_eq_trivial
  3636   Eps_eq           -> some_eq_trivial
  3637 
  3638 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3639 
  3640 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3641 instead);
  3642 
  3643 * HOL: the recursion equations generated by 'recdef' are now called
  3644 f.simps instead of f.rules;
  3645 
  3646 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3647 
  3648 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3649 sometimes be needed;
  3650 
  3651 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3652 
  3653 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3654 
  3655 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3656 product is now "<*>" instead of "Times"; the lexicographic product is
  3657 now "<*lex*>" instead of "**";
  3658 
  3659 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3660 of main HOL, but was unused); better use HOL's datatype package;
  3661 
  3662 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3663 the old syntax may be recovered as follows:
  3664 
  3665   syntax (symbols)
  3666     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3667       (infixl "\\<oplus>" 100)
  3668 
  3669 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3670 
  3671 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3672 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3673 internally;
  3674 
  3675 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3676 changed from A/r to A//r;
  3677 
  3678 * ZF: new treatment of arithmetic (nat & int) may break some old
  3679 proofs;
  3680 
  3681 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3682 rulify -> rule_format, elimify -> elim_format, ...);
  3683 
  3684 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3685 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3686 should have to change intro!! to intro? only); replaced "delrule" by
  3687 "rule del";
  3688 
  3689 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3690 
  3691 * Provers: strengthened force_tac by using new first_best_tac;
  3692 
  3693 * LaTeX document preparation: several changes of isabelle.sty (see
  3694 lib/texinputs);
  3695 
  3696 
  3697 *** Document preparation ***
  3698 
  3699 * formal comments (text blocks etc.) in new-style theories may now
  3700 contain antiquotations of thm/prop/term/typ/text to be presented
  3701 according to latex print mode; concrete syntax is like this:
  3702 @{term[show_types] "f(x) = a + x"};
  3703 
  3704 * isatool mkdir provides easy setup of Isabelle session directories,
  3705 including proper document sources;
  3706 
  3707 * generated LaTeX sources are now deleted after successful run
  3708 (isatool document -c); may retain a copy somewhere else via -D option
  3709 of isatool usedir;
  3710 
  3711 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3712 style files, achieving self-contained LaTeX sources and simplifying
  3713 LaTeX debugging;
  3714 
  3715 * old-style theories now produce (crude) LaTeX output as well;
  3716 
  3717 * browser info session directories are now self-contained (may be put
  3718 on WWW server seperately); improved graphs of nested sessions; removed
  3719 graph for 'all sessions';
  3720 
  3721 * several improvements in isabelle style files; \isabellestyle{it}
  3722 produces fake math mode output; \isamarkupheader is now \section by
  3723 default; see lib/texinputs/isabelle.sty etc.;
  3724 
  3725 
  3726 *** Isar ***
  3727 
  3728 * Isar/Pure: local results and corresponding term bindings are now
  3729 subject to Hindley-Milner polymorphism (similar to ML); this
  3730 accommodates incremental type-inference very nicely;
  3731 
  3732 * Isar/Pure: new derived language element 'obtain' supports
  3733 generalized existence reasoning;
  3734 
  3735 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3736 support accumulation of results, without applying any rules yet;
  3737 useful to collect intermediate results without explicit name
  3738 references, and for use with transitivity rules with more than 2
  3739 premises;
  3740 
  3741 * Isar/Pure: scalable support for case-analysis type proofs: new
  3742 'case' language element refers to local contexts symbolically, as
  3743 produced by certain proof methods; internally, case names are attached
  3744 to theorems as "tags";
  3745 
  3746 * Isar/Pure: theory command 'hide' removes declarations from
  3747 class/type/const name spaces;
  3748 
  3749 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3750 indicate potential overloading;
  3751 
  3752 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3753 
  3754 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3755 "{a,b,c}" instead of {a,b,c};
  3756 
  3757 * Isar/Pure now provides its own version of intro/elim/dest
  3758 attributes; useful for building new logics, but beware of confusion
  3759 with the version in Provers/classical;
  3760 
  3761 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3762 case name 'antecedent';
  3763 
  3764 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3765 to the current context is now done automatically);
  3766 
  3767 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3768 for definining proof methods in ML;
  3769 
  3770 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3771 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3772 most cases, one should have to change intro!! to intro? only);
  3773 replaced "delrule" by "rule del";
  3774 
  3775 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3776 'symmetric' attribute (the latter supercedes [RS sym]);
  3777 
  3778 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3779 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3780 well (including splits);
  3781 
  3782 * Isar/Provers: Simplifier and Classical methods now support all kind
  3783 of modifiers used in the past, including 'cong', 'iff', etc.
  3784 
  3785 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3786 of Simplifier and Classical reasoner);
  3787 
  3788 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3789 now support named cases; major packages (inductive, datatype, primrec,
  3790 recdef) support case names and properly name parameters;
  3791 
  3792 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3793 monotonicity conditions are extracted to be proven at end of
  3794 calculations;
  3795 
  3796 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3797 method anyway;
  3798 
  3799 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3800 split_if split_if_asm; datatype package provides theorems foo.splits =
  3801 foo.split foo.split_asm for each datatype;
  3802 
  3803 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3804 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3805 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3806 use "(cases (simplified))" method in proper proof texts);
  3807 
  3808 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3809 
  3810 * Isar: names of theorems etc. may be natural numbers as well;
  3811 
  3812 * Isar: 'pr' command: optional arguments for goals_limit and
  3813 ProofContext.prems_limit; no longer prints theory contexts, but only
  3814 proof states;
  3815 
  3816 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3817 additional print modes to be specified; e.g. "pr(latex)" will print
  3818 proof state according to the Isabelle LaTeX style;
  3819 
  3820 * Isar: improved support for emulating tactic scripts, including proof
  3821 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3822 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3823 (for HOL datatypes);
  3824 
  3825 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3826 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3827 'proof method scripts' have to be in depth-first order;
  3828 
  3829 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3830 
  3831 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3832 should instead use individual commands for printing items
  3833 (print_commands, print_methods etc.);
  3834 
  3835 * Isar: added 'nothing' --- the empty list of theorems;
  3836 
  3837 
  3838 *** HOL ***
  3839 
  3840 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3841 corresponding virtual machine and a specification of its bytecode
  3842 verifier and a lightweight bytecode verifier, including proofs of
  3843 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3844 Cornelia Pusch (see also the homepage of project Bali at
  3845 http://isabelle.in.tum.de/Bali/);
  3846 
  3847 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3848 Clemens Ballarin;
  3849 
  3850 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3851 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3852 Rasmussen;
  3853 
  3854 * HOL/Lattice: fundamental concepts of lattice theory and order
  3855 structures, including duals, properties of bounds versus algebraic
  3856 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3857 Theorem for complete lattices etc.; may also serve as a demonstration
  3858 for abstract algebraic reasoning using axiomatic type classes, and
  3859 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3860 
  3861 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3862 von Oheimb;
  3863 
  3864 * HOL/IMPP: extension of IMP with local variables and mutually
  3865 recursive procedures, by David von Oheimb;
  3866 
  3867 * HOL/Lambda: converted into new-style theory and document;
  3868 
  3869 * HOL/ex/Multiquote: example of multiple nested quotations and
  3870 anti-quotations -- basically a generalized version of de-Bruijn
  3871 representation; very useful in avoiding lifting of operations;
  3872 
  3873 * HOL/record: added general record equality rule to simpset; fixed
  3874 select-update simplification procedure to handle extended records as
  3875 well; admit "r" as field name;
  3876 
  3877 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3878 other numeric types and also as the identity of groups, rings, etc.;
  3879 
  3880 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3881 Types nat and int belong to this axclass;
  3882 
  3883 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3884    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3885    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3886   two terms #m*u and #n*u are replaced by #(m+n)*u
  3887     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3888   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3889     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3890 
  3891 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3892 powerful prover for predicate logic but knows nothing of clasets; see
  3893 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3894 
  3895 * HOL: new version of "case_tac" subsumes both boolean case split and
  3896 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3897 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3898 
  3899 * HOL: simplification no longer dives into case-expressions: only the
  3900 selector expression is simplified, but not the remaining arms; to
  3901 enable full simplification of case-expressions for datatype t, you may
  3902 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3903 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3904 
  3905 * HOL/recdef: the recursion equations generated by 'recdef' for
  3906 function 'f' are now called f.simps instead of f.rules; if all
  3907 termination conditions are proved automatically, these simplification
  3908 rules are added to the simpset, as in primrec; rules may be named
  3909 individually as well, resulting in a separate list of theorems for
  3910 each equation;
  3911 
  3912 * HOL/While is a new theory that provides a while-combinator. It
  3913 permits the definition of tail-recursive functions without the
  3914 provision of a termination measure. The latter is necessary once the
  3915 invariant proof rule for while is applied.
  3916 
  3917 * HOL: new (overloaded) notation for the set of elements below/above
  3918 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3919 
  3920 * HOL: theorems impI, allI, ballI bound as "strip";
  3921 
  3922 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3923 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3924 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3925 
  3926 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3927 
  3928 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3929 main HOL, but was unused);
  3930 
  3931 * HOL: fewer consts declared as global (e.g. have to refer to
  3932 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3933 
  3934 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3935 in case of overlap with user translations (e.g. judgements over
  3936 tuples); (note that the underlying logical represenation is still
  3937 bogus);
  3938 
  3939 
  3940 *** ZF ***
  3941 
  3942 * ZF: simplification automatically cancels common terms in arithmetic
  3943 expressions over nat and int;
  3944 
  3945 * ZF: new treatment of nat to minimize type-checking: all operators
  3946 coerce their operands to a natural number using the function natify,
  3947 making the algebraic laws unconditional;
  3948 
  3949 * ZF: as above, for int: operators coerce their operands to an integer
  3950 using the function intify;
  3951 
  3952 * ZF: the integer library now contains many of the usual laws for the
  3953 orderings, including $<=, and monotonicity laws for $+ and $*;
  3954 
  3955 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3956 simplification;
  3957 
  3958 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3959 to the simplifier and classical reasoner simultaneously;
  3960 
  3961 
  3962 *** General ***
  3963 
  3964 * Provers: blast_tac now handles actual object-logic rules as
  3965 assumptions; note that auto_tac uses blast_tac internally as well;
  3966 
  3967 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3968 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3969 
  3970 * Provers: delrules now handles destruct rules as well (no longer need
  3971 explicit make_elim);
  3972 
  3973 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3974   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3975 use instead the strong form,
  3976   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3977 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3978 from destruct-rules;
  3979 
  3980 * Provers: Simplifier.easy_setup provides a fast path to basic
  3981 Simplifier setup for new object-logics;
  3982 
  3983 * Pure: AST translation rules no longer require constant head on LHS;
  3984 
  3985 * Pure: improved name spaces: ambiguous output is qualified; support
  3986 for hiding of names;
  3987 
  3988 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3989 XSYMBOL_HOME; no longer need to do manual configuration in most
  3990 situations;
  3991 
  3992 * system: compression of ML heaps images may now be controlled via -c
  3993 option of isabelle and isatool usedir (currently only observed by
  3994 Poly/ML);
  3995 
  3996 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3997 useful for remote X11);
  3998 
  3999 * system: provide TAGS file for Isabelle sources;
  4000 
  4001 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4002 order;
  4003 
  4004 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4005 timing flag supersedes proof_timing and Toplevel.trace;
  4006 
  4007 * ML: new combinators |>> and |>>> for incremental transformations
  4008 with secondary results (e.g. certain theory extensions):
  4009 
  4010 * ML: PureThy.add_defs gets additional argument to indicate potential
  4011 overloading (usually false);
  4012 
  4013 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4014 results;
  4015 
  4016 
  4017 
  4018 New in Isabelle99 (October 1999)
  4019 --------------------------------
  4020 
  4021 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4022 
  4023 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4024 are no longer simplified.  (This allows the simplifier to unfold recursive
  4025 functional programs.)  To restore the old behaviour, declare
  4026 
  4027     Delcongs [if_weak_cong];
  4028 
  4029 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4030 complement;
  4031 
  4032 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4033 
  4034 * HOL/datatype: mutual_induct_tac no longer exists --
  4035   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4036 
  4037 * HOL/typedef: fixed type inference for representing set; type
  4038 arguments now have to occur explicitly on the rhs as type constraints;
  4039 
  4040 * ZF: The con_defs part of an inductive definition may no longer refer
  4041 to constants declared in the same theory;
  4042 
  4043 * HOL, ZF: the function mk_cases, generated by the inductive
  4044 definition package, has lost an argument.  To simplify its result, it
  4045 uses the default simpset instead of a supplied list of theorems.
  4046 
  4047 * HOL/List: the constructors of type list are now Nil and Cons;
  4048 
  4049 * Simplifier: the type of the infix ML functions
  4050         setSSolver addSSolver setSolver addSolver
  4051 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4052 for packaging solvers. A solver is created via
  4053         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4054 where the string argument is only a comment.
  4055 
  4056 
  4057 *** Proof tools ***
  4058 
  4059 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4060 decision procedure for linear arithmetic. Currently it is used for
  4061 types `nat', `int', and `real' in HOL (see below); it can, should and
  4062 will be instantiated for other types and logics as well.
  4063 
  4064 * The simplifier now accepts rewrite rules with flexible heads, eg
  4065      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4066   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4067   matching.
  4068 
  4069 
  4070 *** General ***
  4071 
  4072 * New Isabelle/Isar subsystem provides an alternative to traditional
  4073 tactical theorem proving; together with the ProofGeneral/isar user
  4074 interface it offers an interactive environment for developing human
  4075 readable proof documents (Isar == Intelligible semi-automated
  4076 reasoning); for further information see isatool doc isar-ref,
  4077 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4078 
  4079 * improved and simplified presentation of theories: better HTML markup
  4080 (including colors), graph views in several sizes; isatool usedir now
  4081 provides a proper interface for user theories (via -P option); actual
  4082 document preparation based on (PDF)LaTeX is available as well (for
  4083 new-style theories only); see isatool doc system for more information;
  4084 
  4085 * native support for Proof General, both for classic Isabelle and
  4086 Isabelle/Isar;
  4087 
  4088 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4089 using the graph browser tool;
  4090 
  4091 * Isabelle manuals now also available as PDF;
  4092 
  4093 * theory loader rewritten from scratch (may not be fully
  4094 bug-compatible); old loadpath variable has been replaced by show_path,
  4095 add_path, del_path, reset_path functions; new operations such as
  4096 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4097 isatool doc ref);
  4098 
  4099 * improved isatool install: option -k creates KDE application icon,
  4100 option -p DIR installs standalone binaries;
  4101 
  4102 * added ML_PLATFORM setting (useful for cross-platform installations);
  4103 more robust handling of platform specific ML images for SML/NJ;
  4104 
  4105 * the settings environment is now statically scoped, i.e. it is never
  4106 created again in sub-processes invoked from isabelle, isatool, or
  4107 Isabelle;
  4108 
  4109 * path element specification '~~' refers to '$ISABELLE_HOME';
  4110 
  4111 * in locales, the "assumes" and "defines" parts may be omitted if
  4112 empty;
  4113 
  4114 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4115 long arrows);
  4116 
  4117 * new print_mode "HTML";
  4118 
  4119 * new flag show_tags controls display of tags of theorems (which are
  4120 basically just comments that may be attached by some tools);
  4121 
  4122 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4123 mode and goal output format:
  4124 
  4125 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4126 244c244
  4127 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4128 ---
  4129 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4130 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4131 181c181
  4132 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4133 ---
  4134 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4135 
  4136 * function bind_thms stores lists of theorems (cf. bind_thm);
  4137 
  4138 * new shorthand tactics ftac, eatac, datac, fatac;
  4139 
  4140 * qed (and friends) now accept "" as result name; in that case the
  4141 theorem is not stored, but proper checks and presentation of the
  4142 result still apply;
  4143 
  4144 * theorem database now also indexes constants "Trueprop", "all",
  4145 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4146 
  4147 
  4148 *** HOL ***
  4149 
  4150 ** HOL arithmetic **
  4151 
  4152 * There are now decision procedures for linear arithmetic over nat and
  4153 int:
  4154 
  4155 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4156 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4157 are treated as atomic; subformulae not involving type `nat' or `int'
  4158 are ignored; quantified subformulae are ignored unless they are
  4159 positive universal or negative existential. The tactic has to be
  4160 invoked by hand and can be a little bit slow. In particular, the
  4161 running time is exponential in the number of occurrences of `min' and
  4162 `max', and `-' on `nat'.
  4163 
  4164 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4165 (negated) (in)equalities among the premises and the conclusion into
  4166 account (i.e. no compound formulae) and does not know about `min' and
  4167 `max', and `-' on `nat'. It is fast and is used automatically by the
  4168 simplifier.
  4169 
  4170 NB: At the moment, these decision procedures do not cope with mixed
  4171 nat/int formulae where the two parts interact, such as `m < n ==>
  4172 int(m) < int(n)'.
  4173 
  4174 * HOL/Numeral provides a generic theory of numerals (encoded
  4175 efficiently as bit strings); setup for types nat/int/real is in place;
  4176 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4177 int, existing theories and proof scripts may require a few additional
  4178 type constraints;
  4179 
  4180 * integer division and remainder can now be performed on constant
  4181 arguments;
  4182 
  4183 * many properties of integer multiplication, division and remainder
  4184 are now available;
  4185 
  4186 * An interface to the Stanford Validity Checker (SVC) is available through the
  4187 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4188 are proved automatically.  SVC must be installed separately, and its results
  4189 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4190 invocation of the underlying oracle).  For SVC see
  4191   http://verify.stanford.edu/SVC
  4192 
  4193 * IsaMakefile: the HOL-Real target now builds an actual image;
  4194 
  4195 
  4196 ** HOL misc **
  4197 
  4198 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4199 (in Isabelle/Isar) -- by Gertrud Bauer;
  4200 
  4201 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4202 analysis for assembly languages with subtypes;
  4203 
  4204 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4205 -- avoids syntactic ambiguities and treats state, transition, and
  4206 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4207 changed syntax and (many) tactics;
  4208 
  4209 * HOL/inductive: Now also handles more general introduction rules such
  4210   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4211   theorems are now maintained within the theory (maintained via the
  4212   "mono" attribute);
  4213 
  4214 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4215   (using function types) such as
  4216 
  4217   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4218 
  4219 * HOL/record: record_simproc (part of the default simpset) takes care
  4220 of selectors applied to updated records; record_split_tac is no longer
  4221 part of the default claset; update_defs may now be removed from the
  4222 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4223 
  4224   claset_ref () := claset() addSWrapper record_split_wrapper;
  4225   Delsimprocs [record_simproc]
  4226 
  4227 * HOL/typedef: fixed type inference for representing set; type
  4228 arguments now have to occur explicitly on the rhs as type constraints;
  4229 
  4230 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4231 names rather than an ML expression;
  4232 
  4233 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4234 supplied later.  Program schemes can be defined, such as
  4235     "While B C s = (if B s then While B C (C s) else s)"
  4236 where the well-founded relation can be chosen after B and C have been given.
  4237 
  4238 * HOL/List: the constructors of type list are now Nil and Cons;
  4239 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4240 course, ML tools referring to List.list.op # etc. have to be adapted;
  4241 
  4242 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4243 disabled by default; run isabelle with option -m HOL to get back to
  4244 the original Gordon/HOL-style output;
  4245 
  4246 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4247 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4248 
  4249 * HOL basic syntax simplified (more orthogonal): all variants of
  4250 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4251 Eps operator is provided as well: "SOME x. P[x]";
  4252 
  4253 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4254 
  4255 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4256 thus available for user theories;
  4257 
  4258 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4259 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4260 time;
  4261 
  4262 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4263 several times and then mp;
  4264 
  4265 
  4266 *** LK ***
  4267 
  4268 * the notation <<...>> is now available as a notation for sequences of
  4269 formulas;
  4270 
  4271 * the simplifier is now installed
  4272 
  4273 * the axiom system has been generalized (thanks to Soren Heilmann)
  4274 
  4275 * the classical reasoner now has a default rule database
  4276 
  4277 
  4278 *** ZF ***
  4279 
  4280 * new primrec section allows primitive recursive functions to be given
  4281 directly (as in HOL) over datatypes and the natural numbers;
  4282 
  4283 * new tactics induct_tac and exhaust_tac for induction (or case
  4284 analysis) over datatypes and the natural numbers;
  4285 
  4286 * the datatype declaration of type T now defines the recursor T_rec;
  4287 
  4288 * simplification automatically does freeness reasoning for datatype
  4289 constructors;
  4290 
  4291 * automatic type-inference, with AddTCs command to insert new
  4292 type-checking rules;
  4293 
  4294 * datatype introduction rules are now added as Safe Introduction rules
  4295 to the claset;
  4296 
  4297 * the syntax "if P then x else y" is now available in addition to
  4298 if(P,x,y);
  4299 
  4300 
  4301 *** Internal programming interfaces ***
  4302 
  4303 * tuned simplifier trace output; new flag debug_simp;
  4304 
  4305 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4306 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4307 
  4308 * AxClass.axclass_tac lost the theory argument;
  4309 
  4310 * tuned current_goals_markers semantics: begin / end goal avoids
  4311 printing empty lines;
  4312 
  4313 * removed prs and prs_fn hook, which was broken because it did not
  4314 include \n in its semantics, forcing writeln to add one
  4315 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4316 string -> unit if you really want to output text without newline;
  4317 
  4318 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4319 plain output, interface builders may have to enable 'isabelle_font'
  4320 mode to get Isabelle font glyphs as before;
  4321 
  4322 * refined token_translation interface; INCOMPATIBILITY: output length
  4323 now of type real instead of int;
  4324 
  4325 * theory loader actions may be traced via new ThyInfo.add_hook
  4326 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4327 your own database of information attached to *whole* theories -- as
  4328 opposed to intra-theory data slots offered via TheoryDataFun;
  4329 
  4330 * proper handling of dangling sort hypotheses (at last!);
  4331 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4332 extra sort hypotheses that can be witnessed from the type signature;
  4333 the force_strip_shyps flag is gone, any remaining shyps are simply
  4334 left in the theorem (with a warning issued by strip_shyps_warning);
  4335 
  4336 
  4337 
  4338 New in Isabelle98-1 (October 1998)
  4339 ----------------------------------
  4340 
  4341 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4342 
  4343 * several changes of automated proof tools;
  4344 
  4345 * HOL: major changes to the inductive and datatype packages, including
  4346 some minor incompatibilities of theory syntax;
  4347 
  4348 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4349 called `inj_on';
  4350 
  4351 * HOL: removed duplicate thms in Arith:
  4352   less_imp_add_less  should be replaced by  trans_less_add1
  4353   le_imp_add_le      should be replaced by  trans_le_add1
  4354 
  4355 * HOL: unary minus is now overloaded (new type constraints may be
  4356 required);
  4357 
  4358 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4359 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4360 now taken as an integer constant.
  4361 
  4362 * Pure: ML function 'theory_of' renamed to 'theory';
  4363 
  4364 
  4365 *** Proof tools ***
  4366 
  4367 * Simplifier:
  4368   1. Asm_full_simp_tac is now more aggressive.
  4369      1. It will sometimes reorient premises if that increases their power to
  4370         simplify.
  4371      2. It does no longer proceed strictly from left to right but may also
  4372         rotate premises to achieve further simplification.
  4373      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4374      old Asm_full_simp_tac in that it does not rotate premises.
  4375   2. The simplifier now knows a little bit about nat-arithmetic.
  4376 
  4377 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4378 allows for selected deletion of wrappers, by introduction of names for
  4379 wrapper functionals.  This implies that addbefore, addSbefore,
  4380 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4381 and that adding two tactics with the same name overwrites the first
  4382 one (emitting a warning).
  4383   type wrapper = (int -> tactic) -> (int -> tactic)
  4384   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4385   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4386   delWrapper, delSWrapper: claset *  string            -> claset
  4387   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4388 
  4389 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4390 semantics; addbefore now affects only the unsafe part of step_tac
  4391 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4392 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4393 by Force_tac;
  4394 
  4395 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4396 compWrapper; added safe wrapper (and access functions for it);
  4397 
  4398 * HOL/split_all_tac is now much faster and fails if there is nothing
  4399 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4400 and the names of the automatically generated variables have changed.
  4401 split_all_tac has moved within claset() from unsafe wrappers to safe
  4402 wrappers, which means that !!-bound variables are split much more
  4403 aggressively, and safe_tac and clarify_tac now split such variables.
  4404 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4405 Note: the same holds for record_split_tac, which does the job of
  4406 split_all_tac for record fields.
  4407 
  4408 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4409 permanently to the default simpset using Addsplits just like
  4410 Addsimps. They can be removed via Delsplits just like
  4411 Delsimps. Lower-case versions are also available.
  4412 
  4413 * HOL/Simplifier: The rule split_if is now part of the default
  4414 simpset. This means that the simplifier will eliminate all occurrences
  4415 of if-then-else in the conclusion of a goal. To prevent this, you can
  4416 either remove split_if completely from the default simpset by
  4417 `Delsplits [split_if]' or remove it in a specific call of the
  4418 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4419 other case splitting rules to/from the default simpset: every datatype
  4420 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4421 t is the name of the datatype).
  4422 
  4423 * Classical reasoner / Simplifier combination: new force_tac (and
  4424 derivatives Force_tac, force) combines rewriting and classical
  4425 reasoning (and whatever other tools) similarly to auto_tac, but is
  4426 aimed to solve the given subgoal completely.
  4427 
  4428 
  4429 *** General ***
  4430 
  4431 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4432 and `goalw': the theory is no longer needed as an explicit argument -
  4433 the current theory context is used; assumptions are no longer returned
  4434 at the ML-level unless one of them starts with ==> or !!; it is
  4435 recommended to convert to these new commands using isatool fixgoal
  4436 (backup your sources first!);
  4437 
  4438 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4439 the current theory context, and 'theory' to lookup stored theories;
  4440 
  4441 * new theory section 'locale' for declaring constants, assumptions and
  4442 definitions that have local scope;
  4443 
  4444 * new theory section 'nonterminals' for purely syntactic types;
  4445 
  4446 * new theory section 'setup' for generic ML setup functions
  4447 (e.g. package initialization);
  4448 
  4449 * the distribution now includes Isabelle icons: see
  4450 lib/logo/isabelle-{small,tiny}.xpm;
  4451 
  4452 * isatool install - install binaries with absolute references to
  4453 ISABELLE_HOME/bin;
  4454 
  4455 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4456 
  4457 * print mode 'emacs' reserved for Isamode;
  4458 
  4459 * support multiple print (ast) translations per constant name;
  4460 
  4461 * theorems involving oracles are now printed with a suffixed [!];
  4462 
  4463 
  4464 *** HOL ***
  4465 
  4466 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4467 
  4468 * HOL/inductive package reorganized and improved: now supports mutual
  4469 definitions such as
  4470 
  4471   inductive EVEN ODD
  4472     intrs
  4473       null "0 : EVEN"
  4474       oddI "n : EVEN ==> Suc n : ODD"
  4475       evenI "n : ODD ==> Suc n : EVEN"
  4476 
  4477 new theorem list "elims" contains an elimination rule for each of the
  4478 recursive sets; inductive definitions now handle disjunctive premises
  4479 correctly (also ZF);
  4480 
  4481 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4482 "mutual_induct" no longer exists - the induction rule is always
  4483 contained in "induct";
  4484 
  4485 
  4486 * HOL/datatype package re-implemented and greatly improved: now
  4487 supports mutually recursive datatypes such as
  4488 
  4489   datatype
  4490     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4491             | SUM ('a aexp) ('a aexp)
  4492             | DIFF ('a aexp) ('a aexp)
  4493             | NUM 'a
  4494   and
  4495     'a bexp = LESS ('a aexp) ('a aexp)
  4496             | AND ('a bexp) ('a bexp)
  4497             | OR ('a bexp) ('a bexp)
  4498 
  4499 as well as indirectly recursive datatypes such as
  4500 
  4501   datatype
  4502     ('a, 'b) term = Var 'a
  4503                   | App 'b ((('a, 'b) term) list)
  4504 
  4505 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4506 induction on mutually / indirectly recursive datatypes.
  4507 
  4508 Primrec equations are now stored in theory and can be accessed via
  4509 <function_name>.simps.
  4510 
  4511 INCOMPATIBILITIES:
  4512 
  4513   - Theories using datatypes must now have theory Datatype as an
  4514     ancestor.
  4515   - The specific <typename>.induct_tac no longer exists - use the
  4516     generic induct_tac instead.
  4517   - natE has been renamed to nat.exhaust - use exhaust_tac
  4518     instead of res_inst_tac ... natE. Note that the variable
  4519     names in nat.exhaust differ from the names in natE, this
  4520     may cause some "fragile" proofs to fail.
  4521   - The theorems split_<typename>_case and split_<typename>_case_asm
  4522     have been renamed to <typename>.split and <typename>.split_asm.
  4523   - Since default sorts of type variables are now handled correctly,
  4524     some datatype definitions may have to be annotated with explicit
  4525     sort constraints.
  4526   - Primrec definitions no longer require function name and type
  4527     of recursive argument.
  4528 
  4529 Consider using isatool fixdatatype to adapt your theories and proof
  4530 scripts to the new package (backup your sources first!).
  4531 
  4532 
  4533 * HOL/record package: considerably improved implementation; now
  4534 includes concrete syntax for record types, terms, updates; theorems
  4535 for surjective pairing and splitting !!-bound record variables; proof
  4536 support is as follows:
  4537 
  4538   1) standard conversions (selectors or updates applied to record
  4539 constructor terms) are part of the standard simpset;
  4540 
  4541   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4542 made part of standard simpset and claset via addIffs;
  4543 
  4544   3) a tactic for record field splitting (record_split_tac) is part of
  4545 the standard claset (addSWrapper);
  4546 
  4547 To get a better idea about these rules you may retrieve them via
  4548 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4549 the name of your record type.
  4550 
  4551 The split tactic 3) conceptually simplifies by the following rule:
  4552 
  4553   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4554 
  4555 Thus any record variable that is bound by meta-all will automatically
  4556 blow up into some record constructor term, consequently the
  4557 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4558 solve record problems automatically.
  4559 
  4560 
  4561 * reorganized the main HOL image: HOL/Integ and String loaded by
  4562 default; theory Main includes everything;
  4563 
  4564 * automatic simplification of integer sums and comparisons, using cancellation;
  4565 
  4566 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4567 
  4568 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4569 
  4570 * many new identities for unions, intersections, set difference, etc.;
  4571 
  4572 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4573 called split_if, split_split, split_sum_case and split_nat_case (to go
  4574 with add/delsplits);
  4575 
  4576 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4577 (?x::unit) = (); this is made part of the default simpset, which COULD
  4578 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4579 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4580 unit_abs_eta_conv is added in order to counter the effect of
  4581 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4582 %u.f();
  4583 
  4584 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4585 makes more sense);
  4586 
  4587 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4588   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4589   disjointness reasoning but breaking a few old proofs.
  4590 
  4591 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4592 to 'converse' from 'inverse' (for compatibility with ZF and some
  4593 literature);
  4594 
  4595 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4596 the well-founded relation;
  4597 
  4598 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4599     Compl A.  The "Compl" syntax remains available as input syntax for this
  4600     release ONLY.
  4601 
  4602 * HOL/Update: new theory of function updates:
  4603     f(a:=b) == %x. if x=a then b else f x
  4604 may also be iterated as in f(a:=b,c:=d,...);
  4605 
  4606 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4607 
  4608 * HOL/List:
  4609   - new function list_update written xs[i:=v] that updates the i-th
  4610     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4611   - new function `upt' written [i..j(] which generates the list
  4612     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4613     bound write [i..j], which is a shorthand for [i..j+1(].
  4614   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4615 
  4616 * HOL/Arith:
  4617   - removed 'pred' (predecessor) function;
  4618   - generalized some theorems about n-1;
  4619   - many new laws about "div" and "mod";
  4620   - new laws about greatest common divisors (see theory ex/Primes);
  4621 
  4622 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4623 instead of "inverse";
  4624 
  4625 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4626   of the multiset ordering;
  4627 
  4628 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4629   (not included by default);
  4630 
  4631 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4632 
  4633 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4634   programs, i.e. different program variables may have different types.
  4635 
  4636 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4637   [previously, this check worked only if the rewrite rule was unconditional]
  4638   Now rew can involve either definitions or equalities (either == or =).
  4639 
  4640 
  4641 *** ZF ***
  4642 
  4643 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4644   only the theorems proved on ZF.ML;
  4645 
  4646 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4647   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4648   disjointness reasoning but breaking a few old proofs.
  4649 
  4650 * ZF/Update: new theory of function updates
  4651     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4652   may also be iterated as in f(a:=b,c:=d,...);
  4653 
  4654 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4655 
  4656 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4657   [previously, this check worked only if the rewrite rule was unconditional]
  4658   Now rew can involve either definitions or equalities (either == or =).
  4659 
  4660 * case_tac provided for compatibility with HOL
  4661     (like the old excluded_middle_tac, but with subgoals swapped)
  4662 
  4663 
  4664 *** Internal programming interfaces ***
  4665 
  4666 * Pure: several new basic modules made available for general use, see
  4667 also src/Pure/README;
  4668 
  4669 * improved the theory data mechanism to support encapsulation (data
  4670 kind name replaced by private Object.kind, acting as authorization
  4671 key); new type-safe user interface via functor TheoryDataFun; generic
  4672 print_data function becomes basically useless;
  4673 
  4674 * removed global_names compatibility flag -- all theory declarations
  4675 are qualified by default;
  4676 
  4677 * module Pure/Syntax now offers quote / antiquote translation
  4678 functions (useful for Hoare logic etc. with implicit dependencies);
  4679 see HOL/ex/Antiquote for an example use;
  4680 
  4681 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4682 cterm -> thm;
  4683 
  4684 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4685 subgoal;
  4686 
  4687 * Display.print_goals function moved to Locale.print_goals;
  4688 
  4689 * standard print function for goals supports current_goals_markers
  4690 variable for marking begin of proof, end of proof, start of goal; the
  4691 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4692 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4693 for example;
  4694 
  4695 
  4696 
  4697 New in Isabelle98 (January 1998)
  4698 --------------------------------
  4699 
  4700 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4701 
  4702 * changed lexical syntax of terms / types: dots made part of long
  4703 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4704 
  4705 * simpset (and claset) reference variable replaced by functions
  4706 simpset / simpset_ref;
  4707 
  4708 * no longer supports theory aliases (via merge) and non-trivial
  4709 implicit merge of thms' signatures;
  4710 
  4711 * most internal names of constants changed due to qualified names;
  4712 
  4713 * changed Pure/Sequence interface (see Pure/seq.ML);
  4714 
  4715 
  4716 *** General Changes ***
  4717 
  4718 * hierachically structured name spaces (for consts, types, axms, thms
  4719 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4720 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4721 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4722 long_names for fully qualified output names; NOTE: ML programs
  4723 (special tactics, packages etc.) referring to internal names may have
  4724 to be adapted to cope with fully qualified names; in case of severe
  4725 backward campatibility problems try setting 'global_names' at compile
  4726 time to have enrything declared within a flat name space; one may also
  4727 fine tune name declarations in theories via the 'global' and 'local'
  4728 section;
  4729 
  4730 * reimplemented the implicit simpset and claset using the new anytype
  4731 data filed in signatures; references simpset:simpset ref etc. are
  4732 replaced by functions simpset:unit->simpset and
  4733 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4734 to patch your ML files accordingly;
  4735 
  4736 * HTML output now includes theory graph data for display with Java
  4737 applet or isatool browser; data generated automatically via isatool
  4738 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4739 
  4740 * defs may now be conditional; improved rewrite_goals_tac to handle
  4741 conditional equations;
  4742 
  4743 * defs now admits additional type arguments, using TYPE('a) syntax;
  4744 
  4745 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4746 creates a new theory node; implicit merge of thms' signatures is
  4747 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4748 transfer:theory->thm->thm in (rare) cases;
  4749 
  4750 * improved handling of draft signatures / theories; draft thms (and
  4751 ctyps, cterms) are automatically promoted to real ones;
  4752 
  4753 * slightly changed interfaces for oracles: admit many per theory, named
  4754 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4755 
  4756 * print_goals: optional output of const types (set show_consts and
  4757 show_types);
  4758 
  4759 * improved output of warnings (###) and errors (***);
  4760 
  4761 * subgoal_tac displays a warning if the new subgoal has type variables;
  4762 
  4763 * removed old README and Makefiles;
  4764 
  4765 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4766 
  4767 * removed obsolete init_pps and init_database;
  4768 
  4769 * deleted the obsolete tactical STATE, which was declared by
  4770     fun STATE tacfun st = tacfun st st;
  4771 
  4772 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4773 (which abbreviates $HOME);
  4774 
  4775 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4776 use isatool fixseq to adapt your ML programs (this works for fully
  4777 qualified references to the Sequence structure only!);
  4778 
  4779 * use_thy no longer requires writable current directory; it always
  4780 reloads .ML *and* .thy file, if either one is out of date;
  4781 
  4782 
  4783 *** Classical Reasoner ***
  4784 
  4785 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4786 tactics that use classical reasoning to simplify a subgoal without
  4787 splitting it into several subgoals;
  4788 
  4789 * Safe_tac: like safe_tac but uses the default claset;
  4790 
  4791 
  4792 *** Simplifier ***
  4793 
  4794 * added simplification meta rules:
  4795     (asm_)(full_)simplify: simpset -> thm -> thm;
  4796 
  4797 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4798 logics (again);
  4799 
  4800 * added prems argument to simplification procedures;
  4801 
  4802 * HOL, FOL, ZF: added infix function `addsplits':
  4803   instead of `<simpset> setloop (split_tac <thms>)'
  4804   you can simply write `<simpset> addsplits <thms>'
  4805 
  4806 
  4807 *** Syntax ***
  4808 
  4809 * TYPE('a) syntax for type reflection terms;
  4810 
  4811 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4812 
  4813 * pretty printer: changed order of mixfix annotation preference (again!);
  4814 
  4815 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4816 
  4817 
  4818 *** HOL ***
  4819 
  4820 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4821   with `addloop' of the simplifier to faciliate case splitting in premises.
  4822 
  4823 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4824 
  4825 * HOL/Auth: new protocol proofs including some for the Internet
  4826   protocol TLS;
  4827 
  4828 * HOL/Map: new theory of `maps' a la VDM;
  4829 
  4830 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4831 cancelling out common nat summands from =, <, <= (in)equalities, or
  4832 differences; simplification procedures nat_cancel_factor for
  4833 cancelling common factor from =, <, <= (in)equalities over natural
  4834 sums; nat_cancel contains both kinds of procedures, it is installed by
  4835 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4836 
  4837 * HOL/simplifier: terms of the form
  4838   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4839   are rewritten to
  4840   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4841   and those of the form
  4842   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4843   are rewritten to
  4844   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4845 
  4846 * HOL/datatype
  4847   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4848 
  4849   P(t_case f1 ... fn x) =
  4850      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4851         ...
  4852        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4853      )
  4854 
  4855   and a theorem `split_t_case_asm' of the form
  4856 
  4857   P(t_case f1 ... fn x) =
  4858     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4859         ...
  4860        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4861      )
  4862   which can be added to a simpset via `addsplits'. The existing theorems
  4863   expand_list_case and expand_option_case have been renamed to
  4864   split_list_case and split_option_case.
  4865 
  4866 * HOL/Arithmetic:
  4867   - `pred n' is automatically converted to `n-1'.
  4868     Users are strongly encouraged not to use `pred' any longer,
  4869     because it will disappear altogether at some point.
  4870   - Users are strongly encouraged to write "0 < n" rather than
  4871     "n ~= 0". Theorems and proof tools have been modified towards this
  4872     `standard'.
  4873 
  4874 * HOL/Lists:
  4875   the function "set_of_list" has been renamed "set" (and its theorems too);
  4876   the function "nth" now takes its arguments in the reverse order and
  4877   has acquired the infix notation "!" as in "xs!n".
  4878 
  4879 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4880 
  4881 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4882   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4883 
  4884 * HOL/record: extensible records with schematic structural subtyping
  4885 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4886 still lacks various theorems and concrete record syntax;
  4887 
  4888 
  4889 *** HOLCF ***
  4890 
  4891 * removed "axioms" and "generated by" sections;
  4892 
  4893 * replaced "ops" section by extended "consts" section, which is capable of
  4894   handling the continuous function space "->" directly;
  4895 
  4896 * domain package:
  4897   . proves theorems immediately and stores them in the theory,
  4898   . creates hierachical name space,
  4899   . now uses normal mixfix annotations (instead of cinfix...),
  4900   . minor changes to some names and values (for consistency),
  4901   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4902   . separator between mutual domain defs: changed "," to "and",
  4903   . improved handling of sort constraints;  now they have to
  4904     appear on the left-hand side of the equations only;
  4905 
  4906 * fixed LAM <x,y,zs>.b syntax;
  4907 
  4908 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4909 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4910 
  4911 
  4912 *** FOL and ZF ***
  4913 
  4914 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4915   with `addloop' of the simplifier to faciliate case splitting in premises.
  4916 
  4917 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4918 in HOL, they strip ALL and --> from proved theorems;
  4919 
  4920 
  4921 
  4922 New in Isabelle94-8 (May 1997)
  4923 ------------------------------
  4924 
  4925 *** General Changes ***
  4926 
  4927 * new utilities to build / run / maintain Isabelle etc. (in parts
  4928 still somewhat experimental); old Makefiles etc. still functional;
  4929 
  4930 * new 'Isabelle System Manual';
  4931 
  4932 * INSTALL text, together with ./configure and ./build scripts;
  4933 
  4934 * reimplemented type inference for greater efficiency, better error
  4935 messages and clean internal interface;
  4936 
  4937 * prlim command for dealing with lots of subgoals (an easier way of
  4938 setting goals_limit);
  4939 
  4940 
  4941 *** Syntax ***
  4942 
  4943 * supports alternative (named) syntax tables (parser and pretty
  4944 printer); internal interface is provided by add_modesyntax(_i);
  4945 
  4946 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4947 be used in conjunction with the Isabelle symbol font; uses the
  4948 "symbols" syntax table;
  4949 
  4950 * added token_translation interface (may translate name tokens in
  4951 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4952 the current print_mode); IMPORTANT: user print translation functions
  4953 are responsible for marking newly introduced bounds
  4954 (Syntax.mark_boundT);
  4955 
  4956 * token translations for modes "xterm" and "xterm_color" that display
  4957 names in bold, underline etc. or colors (which requires a color
  4958 version of xterm);
  4959 
  4960 * infixes may now be declared with names independent of their syntax;
  4961 
  4962 * added typed_print_translation (like print_translation, but may
  4963 access type of constant);
  4964 
  4965 
  4966 *** Classical Reasoner ***
  4967 
  4968 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4969 some limitations.  Blast_tac...
  4970   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4971   + ignores elimination rules that don't have the correct format
  4972         (the conclusion MUST be a formula variable)
  4973   + ignores types, which can make HOL proofs fail
  4974   + rules must not require higher-order unification, e.g. apply_type in ZF
  4975     [message "Function Var's argument not a bound variable" relates to this]
  4976   + its proof strategy is more general but can actually be slower
  4977 
  4978 * substitution with equality assumptions no longer permutes other
  4979 assumptions;
  4980 
  4981 * minor changes in semantics of addafter (now called addaltern); renamed
  4982 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4983 (and access functions for it);
  4984 
  4985 * improved combination of classical reasoner and simplifier:
  4986   + functions for handling clasimpsets
  4987   + improvement of addss: now the simplifier is called _after_ the
  4988     safe steps.
  4989   + safe variant of addss called addSss: uses safe simplifications
  4990     _during_ the safe steps. It is more complete as it allows multiple
  4991     instantiations of unknowns (e.g. with slow_tac).
  4992 
  4993 *** Simplifier ***
  4994 
  4995 * added interface for simplification procedures (functions that
  4996 produce *proven* rewrite rules on the fly, depending on current
  4997 redex);
  4998 
  4999 * ordering on terms as parameter (used for ordered rewriting);
  5000 
  5001 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5002 
  5003 * the solver is now split into a safe and an unsafe part.
  5004 This should be invisible for the normal user, except that the
  5005 functions setsolver and addsolver have been renamed to setSolver and
  5006 addSolver; added safe_asm_full_simp_tac;
  5007 
  5008 
  5009 *** HOL ***
  5010 
  5011 * a generic induction tactic `induct_tac' which works for all datatypes and
  5012 also for type `nat';
  5013 
  5014 * a generic case distinction tactic `exhaust_tac' which works for all
  5015 datatypes and also for type `nat';
  5016 
  5017 * each datatype comes with a function `size';
  5018 
  5019 * patterns in case expressions allow tuple patterns as arguments to
  5020 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5021 
  5022 * primrec now also works with type nat;
  5023 
  5024 * recdef: a new declaration form, allows general recursive functions to be
  5025 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5026 
  5027 * the constant for negation has been renamed from "not" to "Not" to
  5028 harmonize with FOL, ZF, LK, etc.;
  5029 
  5030 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5031 infinite lists;
  5032 
  5033 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5034 
  5035 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5036 problems in commutative rings, using axiomatic type classes for + and *;
  5037 
  5038 * more examples in HOL/MiniML and HOL/Auth;
  5039 
  5040 * more default rewrite rules for quantifiers, union/intersection;
  5041 
  5042 * a new constant `arbitrary == @x.False';
  5043 
  5044 * HOLCF/IOA replaces old HOL/IOA;
  5045 
  5046 * HOLCF changes: derived all rules and arities
  5047   + axiomatic type classes instead of classes
  5048   + typedef instead of faking type definitions
  5049   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5050   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5051   + eliminated the types void, one, tr
  5052   + use unit lift and bool lift (with translations) instead of one and tr
  5053   + eliminated blift from Lift3.thy (use Def instead of blift)
  5054   all eliminated rules are derived as theorems --> no visible changes ;
  5055 
  5056 
  5057 *** ZF ***
  5058 
  5059 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5060 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5061 as ZF_cs addSIs [equalityI];
  5062 
  5063 
  5064 
  5065 New in Isabelle94-7 (November 96)
  5066 ---------------------------------
  5067 
  5068 * allowing negative levels (as offsets) in prlev and choplev;
  5069 
  5070 * super-linear speedup for large simplifications;
  5071 
  5072 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5073 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5074 FAIL); can suppress it using the command Delsimps (ex_simps @
  5075 all_simps); De Morgan laws are also now included, by default;
  5076 
  5077 * improved printing of ==>  :  ~:
  5078 
  5079 * new object-logic "Sequents" adds linear logic, while replacing LK
  5080 and Modal (thanks to Sara Kalvala);
  5081 
  5082 * HOL/Auth: correctness proofs for authentication protocols;
  5083 
  5084 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5085 examples on HOL/Auth);
  5086 
  5087 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5088 the rewriter and classical reasoner simultaneously;
  5089 
  5090 * function uresult no longer returns theorems in "standard" format;
  5091 regain previous version by: val uresult = standard o uresult;
  5092 
  5093 
  5094 
  5095 New in Isabelle94-6
  5096 -------------------
  5097 
  5098 * oracles -- these establish an interface between Isabelle and trusted
  5099 external reasoners, which may deliver results as theorems;
  5100 
  5101 * proof objects (in particular record all uses of oracles);
  5102 
  5103 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5104 
  5105 * "constdefs" section in theory files;
  5106 
  5107 * "primrec" section (HOL) no longer requires names;
  5108 
  5109 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5110 
  5111 
  5112 
  5113 New in Isabelle94-5
  5114 -------------------
  5115 
  5116 * reduced space requirements;
  5117 
  5118 * automatic HTML generation from theories;
  5119 
  5120 * theory files no longer require "..." (quotes) around most types;
  5121 
  5122 * new examples, including two proofs of the Church-Rosser theorem;
  5123 
  5124 * non-curried (1994) version of HOL is no longer distributed;
  5125 
  5126 
  5127 
  5128 New in Isabelle94-4
  5129 -------------------
  5130 
  5131 * greatly reduced space requirements;
  5132 
  5133 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5134 
  5135 * searchable theorem database (see the section "Retrieving theorems" on
  5136 page 8 of the Reference Manual);
  5137 
  5138 * new examples, including Grabczewski's monumental case study of the
  5139 Axiom of Choice;
  5140 
  5141 * The previous version of HOL renamed to Old_HOL;
  5142 
  5143 * The new version of HOL (previously called CHOL) uses a curried syntax
  5144 for functions.  Application looks like f a b instead of f(a,b);
  5145 
  5146 * Mutually recursive inductive definitions finally work in HOL;
  5147 
  5148 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5149 translates to the operator "split";
  5150 
  5151 
  5152 
  5153 New in Isabelle94-3
  5154 -------------------
  5155 
  5156 * new infix operator, addss, allowing the classical reasoner to
  5157 perform simplification at each step of its search.  Example:
  5158         fast_tac (cs addss ss)
  5159 
  5160 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5161 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5162 look like (a,b) instead of <a,b>;
  5163 
  5164 * PLEASE NOTE: CHOL will eventually replace HOL!
  5165 
  5166 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5167 It translates to the operator "split".  A new theory of integers is available;
  5168 
  5169 * In ZF, integer numerals now denote two's-complement binary integers.
  5170 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5171 
  5172 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5173 of the Axiom of Choice;
  5174 
  5175 
  5176 
  5177 New in Isabelle94-2
  5178 -------------------
  5179 
  5180 * Significantly faster resolution;
  5181 
  5182 * the different sections in a .thy file can now be mixed and repeated
  5183 freely;
  5184 
  5185 * Database of theorems for FOL, HOL and ZF.  New
  5186 commands including qed, qed_goal and bind_thm store theorems in the database.
  5187 
  5188 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5189 a given theory (thms_of), or find out what theory a theorem was proved in
  5190 (theory_of_thm);
  5191 
  5192 * Bugs fixed in the inductive definition and datatype packages;
  5193 
  5194 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5195 and HOL_dup_cs obsolete;
  5196 
  5197 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5198 have been removed;
  5199 
  5200 * Simpler definition of function space in ZF;
  5201 
  5202 * new results about cardinal and ordinal arithmetic in ZF;
  5203 
  5204 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5205 types;
  5206 
  5207 :mode=text:wrap=hard:maxLineLen=72:
  5208 $Id$