NEWS
author haftmann
Wed Jan 30 10:57:44 2008 +0100 (2008-01-30)
changeset 26013 8764a1f1253b
parent 26006 c973b4981276
child 26041 c2e15e65165f
permissions -rw-r--r--
Theorem Inductive.lfp_ordinal_induct generalized to complete lattices
     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.  Supersedes previous
    33 experimental versions.
    34 
    35 
    36 *** HOL ***
    37 
    38 * Theorem Inductive.lfp_ordinal_induct generalized to complete lattices.  The
    39 form set-specific version is available as Inductive.lfp_ordinal_induct_set.
    40 
    41 * Theorems "power.simps" renamed to "power_int.simps".
    42 
    43 * New class semiring_div provides basic abstract properties of semirings
    44 with division and modulo operations.  Subsumes former class dvd_mod.
    45 
    46 * Merged theories IntDef, Numeral and IntArith into unified theory Int.
    47 INCOMPATIBILITY.
    48 
    49 * Theory Library/Code_Index: type "index" now represents natural numbers rather
    50 than integers.  INCOMPATIBILITY.
    51 
    52 * New class "uminus" with operation "uminus" (split of from class "minus"
    53 which now only has operation "minus", binary).  INCOMPATIBILITY.
    54 
    55 * New primrec package.  Specification syntax conforms in style to
    56 definition/function/....  No separate induction rule is provided.
    57 The "primrec" command distinguishes old-style and new-style specifications
    58 by syntax.  The former primrec package is now named OldPrimrecPackage.
    59 When adjusting theories, beware: constants stemming for new-style
    60 primrec specifications have authentic syntax.
    61 
    62 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
    63 
    64 * Library/ListSpace: new theory of arithmetic vector operations.
    65 
    66 * Constants "card", "internal_split", "option_map" now with authentic
    67 syntax.  INCOMPATIBILITY.
    68 
    69 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
    70 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
    71 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
    72 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
    73 Sup_set_def, le_def, less_def, option_map_def now with object
    74 equality.  INCOMPATIBILITY.
    75 
    76 * New method "induction_scheme" derives user-specified induction rules
    77 from wellfounded induction and completeness of patterns. This factors
    78 out some operations that are done internally by the function package
    79 and makes them available separately. See "HOL/ex/Induction_Scheme.thy"
    80 for examples,
    81 
    82 * Records. Removed K_record, and replaced it by pure lambda term
    83 %x. c. The simplifier setup is now more robust against eta expansion.
    84 INCOMPATIBILITY: in cases explicitly referring to K_record.
    85 
    86 * Metis prover is now an order of magnitude faster, and also works
    87 with multithreading.
    88 
    89 
    90 *** ML ***
    91 
    92 * The ``print mode'' is now a thread-local value derived from a global
    93 template (the former print_mode reference), thus access becomes
    94 non-critical.  The global print_mode reference is for session
    95 management only; user-code should use print_mode_value,
    96 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
    97 
    98 
    99 *** System ***
   100 
   101 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
   102 in accordance with Proof General 3.7, which prefers GNU emacs.
   103 
   104 * Multithreading.max_threads := 0 refers to the number of actual CPU
   105 cores of the underlying machine, which is a good starting point for
   106 optimal performance tuning.  The corresponding usedir option -M allows
   107 "max" as an alias for "0".  WARNING: does not work on certain versions
   108 of Mac OS (with Poly/ML 5.1).
   109 
   110 * isatool tty runs Isabelle process with plain tty interaction;
   111 optional line editor may be specified via ISABELLE_LINE_EDITOR
   112 setting, the default settings attempt to locate "ledit" and "rlwrap".
   113 
   114 * isatool browser now works with Cygwin as well, using general
   115 "javapath" function defined in Isabelle process environment.
   116 
   117 * isabelle-process: non-ML sessions are run with "nice", to prevent
   118 Isabelle from flooding interactive front-ends (notably ProofGeneral /
   119 XEmacs).
   120 
   121 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   122 provides general wrapper for managing an Isabelle process in a robust
   123 fashion, with ``cooked'' output from stdin/stderr.
   124 
   125 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   126 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   127 
   128 
   129 
   130 New in Isabelle2007 (November 2007)
   131 -----------------------------------
   132 
   133 *** General ***
   134 
   135 * More uniform information about legacy features, notably a
   136 warning/error of "Legacy feature: ...", depending on the state of the
   137 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   138 legacy features will disappear eventually.
   139 
   140 * Theory syntax: the header format ``theory A = B + C:'' has been
   141 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   142 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   143 
   144 * Theory syntax: the old non-Isar theory file format has been
   145 discontinued altogether.  Note that ML proof scripts may still be used
   146 with Isar theories; migration is usually quite simple with the ML
   147 function use_legacy_bindings.  INCOMPATIBILITY.
   148 
   149 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   150 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   151 quotes.
   152 
   153 * Theory loader: be more serious about observing the static theory
   154 header specifications (including optional directories), but not the
   155 accidental file locations of previously successful loads.  The strict
   156 update policy of former update_thy is now already performed by
   157 use_thy, so the former has been removed; use_thys updates several
   158 theories simultaneously, just as 'imports' within a theory header
   159 specification, but without merging the results.  Potential
   160 INCOMPATIBILITY: may need to refine theory headers and commands
   161 ROOT.ML which depend on load order.
   162 
   163 * Theory loader: optional support for content-based file
   164 identification, instead of the traditional scheme of full physical
   165 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   166 (cf. the system manual).  The new scheme allows to work with
   167 non-finished theories in persistent session images, such that source
   168 files may be moved later on without requiring reloads.
   169 
   170 * Theory loader: old-style ML proof scripts being *attached* to a thy
   171 file (with the same base name as the theory) are considered a legacy
   172 feature, which will disappear eventually. Even now, the theory loader
   173 no longer maintains dependencies on such files.
   174 
   175 * Syntax: the scope for resolving ambiguities via type-inference is
   176 now limited to individual terms, instead of whole simultaneous
   177 specifications as before. This greatly reduces the complexity of the
   178 syntax module and improves flexibility by separating parsing and
   179 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
   180 'fixes' etc.) are required in rare situations.
   181 
   182 * Syntax: constants introduced by new-style packages ('definition',
   183 'abbreviation' etc.) are passed through the syntax module in
   184 ``authentic mode''. This means that associated mixfix annotations
   185 really stick to such constants, independently of potential name space
   186 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
   187 trees are represented slightly differently, may need to adapt syntax
   188 translations accordingly. Use CONST marker in 'translations' and
   189 @{const_syntax} antiquotation in 'parse_translation' etc.
   190 
   191 * Legacy goal package: reduced interface to the bare minimum required
   192 to keep existing proof scripts running.  Most other user-level
   193 functions are now part of the OldGoals structure, which is *not* open
   194 by default (consider isatool expandshort before open OldGoals).
   195 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   196 these tend to cause confusion about the actual goal (!) context being
   197 used here, which is not necessarily the same as the_context().
   198 
   199 * Command 'find_theorems': supports "*" wild-card in "name:"
   200 criterion; "with_dups" option.  Certain ProofGeneral versions might
   201 support a specific search form (see ProofGeneral/CHANGES).
   202 
   203 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   204 by default, which means that "prems" (and also "fixed variables") are
   205 suppressed from proof state output.  Note that the ProofGeneral
   206 settings mechanism allows to change and save options persistently, but
   207 older versions of Isabelle will fail to start up if a negative prems
   208 limit is imposed.
   209 
   210 * Local theory targets may be specified by non-nested blocks of
   211 ``context/locale/class ... begin'' followed by ``end''.  The body may
   212 contain definitions, theorems etc., including any derived mechanism
   213 that has been implemented on top of these primitives.  This concept
   214 generalizes the existing ``theorem (in ...)'' towards more versatility
   215 and scalability.
   216 
   217 * Proof General interface: proper undo of final 'end' command;
   218 discontinued Isabelle/classic mode (ML proof scripts).
   219 
   220 
   221 *** Document preparation ***
   222 
   223 * Added antiquotation @{theory name} which prints the given name,
   224 after checking that it refers to a valid ancestor theory in the
   225 current context.
   226 
   227 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   228 check the given source text as ML type/structure, printing verbatim.
   229 
   230 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   231 "c args == rhs" given in the current context.  (Any number of
   232 arguments may be given on the LHS.)
   233 
   234 
   235 *** Pure ***
   236 
   237 * The 'class' package offers a combination of axclass and locale to
   238 achieve Haskell-like type classes in Isabelle.  Definitions and
   239 theorems within a class context produce both relative results (with
   240 implicit parameters according to the locale context), and polymorphic
   241 constants with qualified polymorphism (according to the class
   242 context).  Within the body context of a 'class' target, a separate
   243 syntax layer ("user space type system") takes care of converting
   244 between global polymorphic consts and internal locale representation.
   245 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   246 "isatool doc classes" provides a tutorial.
   247 
   248 * Generic code generator framework allows to generate executable
   249 code for ML and Haskell (including Isabelle classes).  A short usage
   250 sketch:
   251 
   252     internal compilation:
   253         export_code <list of constants (term syntax)> in SML
   254     writing SML code to a file:
   255         export_code <list of constants (term syntax)> in SML <filename>
   256     writing OCaml code to a file:
   257         export_code <list of constants (term syntax)> in OCaml <filename>
   258     writing Haskell code to a bunch of files:
   259         export_code <list of constants (term syntax)> in Haskell <filename>
   260 
   261     evaluating closed propositions to True/False using code generation:
   262         method ``eval''
   263 
   264 Reasonable default setup of framework in HOL.
   265 
   266 Theorem attributs for selecting and transforming function equations theorems:
   267 
   268     [code fun]:        select a theorem as function equation for a specific constant
   269     [code fun del]:    deselect a theorem as function equation for a specific constant
   270     [code inline]:     select an equation theorem for unfolding (inlining) in place
   271     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   272 
   273 User-defined serializations (target in {SML, OCaml, Haskell}):
   274 
   275     code_const <and-list of constants (term syntax)>
   276       {(target) <and-list of const target syntax>}+
   277 
   278     code_type <and-list of type constructors>
   279       {(target) <and-list of type target syntax>}+
   280 
   281     code_instance <and-list of instances>
   282       {(target)}+
   283         where instance ::= <type constructor> :: <class>
   284 
   285     code_class <and_list of classes>
   286       {(target) <and-list of class target syntax>}+
   287         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   288 
   289 code_instance and code_class only are effective to target Haskell.
   290 
   291 For example usage see src/HOL/ex/Codegenerator.thy and
   292 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   293 generation from Isabelle/HOL theories is available via "isatool doc
   294 codegen".
   295 
   296 * Code generator: consts in 'consts_code' Isar commands are now
   297 referred to by usual term syntax (including optional type
   298 annotations).
   299 
   300 * Command 'no_translations' removes translation rules from theory
   301 syntax.
   302 
   303 * Overloaded definitions are now actually checked for acyclic
   304 dependencies.  The overloading scheme is slightly more general than
   305 that of Haskell98, although Isabelle does not demand an exact
   306 correspondence to type class and instance declarations.
   307 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   308 exotic versions of overloading -- at the discretion of the user!
   309 
   310 Polymorphic constants are represented via type arguments, i.e. the
   311 instantiation that matches an instance against the most general
   312 declaration given in the signature.  For example, with the declaration
   313 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   314 as c(nat).  Overloading is essentially simultaneous structural
   315 recursion over such type arguments.  Incomplete specification patterns
   316 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   317 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   318 Command 'print_theory' outputs the normalized system of recursive
   319 equations, see section "definitions".
   320 
   321 * Configuration options are maintained within the theory or proof
   322 context (with name and type bool/int/string), providing a very simple
   323 interface to a poor-man's version of general context data.  Tools may
   324 declare options in ML (e.g. using Attrib.config_int) and then refer to
   325 these values using Config.get etc.  Users may change options via an
   326 associated attribute of the same name.  This form of context
   327 declaration works particularly well with commands 'declare' or
   328 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   329 very easy to avoid global references, which would not observe Isar
   330 toplevel undo/redo and fail to work with multithreading.
   331 
   332 Various global ML references of Pure and HOL have been turned into
   333 configuration options:
   334 
   335   Unify.search_bound		unify_search_bound
   336   Unify.trace_bound		unify_trace_bound
   337   Unify.trace_simp		unify_trace_simp
   338   Unify.trace_types		unify_trace_types
   339   Simplifier.simp_depth_limit	simp_depth_limit
   340   Blast.depth_limit		blast_depth_limit
   341   DatatypeProp.dtK		datatype_distinctness_limit
   342   fast_arith_neq_limit  	fast_arith_neq_limit
   343   fast_arith_split_limit	fast_arith_split_limit
   344 
   345 * Named collections of theorems may be easily installed as context
   346 data using the functor NamedThmsFun (see also
   347 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   348 attributes; there is also a toplevel print command.  This facility is
   349 just a common case of general context data, which is the preferred way
   350 for anything more complex than just a list of facts in canonical
   351 order.
   352 
   353 * Isar: command 'declaration' augments a local theory by generic
   354 declaration functions written in ML.  This enables arbitrary content
   355 being added to the context, depending on a morphism that tells the
   356 difference of the original declaration context wrt. the application
   357 context encountered later on.
   358 
   359 * Isar: proper interfaces for simplification procedures.  Command
   360 'simproc_setup' declares named simprocs (with match patterns, and body
   361 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   362 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   363 
   364 * Isar: an extra pair of brackets around attribute declarations
   365 abbreviates a theorem reference involving an internal dummy fact,
   366 which will be ignored later --- only the effect of the attribute on
   367 the background context will persist.  This form of in-place
   368 declarations is particularly useful with commands like 'declare' and
   369 'using', for example ``have A using [[simproc a]] by simp''.
   370 
   371 * Isar: method "assumption" (and implicit closing of subproofs) now
   372 takes simple non-atomic goal assumptions into account: after applying
   373 an assumption as a rule the resulting subgoals are solved by atomic
   374 assumption steps.  This is particularly useful to finish 'obtain'
   375 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   376 without referring to the original premise "!!x. P x ==> thesis" in the
   377 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   378 more permissive.
   379 
   380 * Isar: implicit use of prems from the Isar proof context is
   381 considered a legacy feature.  Common applications like ``have A .''
   382 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   383 referencing facts explicitly here improves readability and
   384 maintainability of proof texts.
   385 
   386 * Isar: improper proof element 'guess' is like 'obtain', but derives
   387 the obtained context from the course of reasoning!  For example:
   388 
   389   assume "EX x y. A x & B y"   -- "any previous fact"
   390   then guess x and y by clarify
   391 
   392 This technique is potentially adventurous, depending on the facts and
   393 proof tools being involved here.
   394 
   395 * Isar: known facts from the proof context may be specified as literal
   396 propositions, using ASCII back-quote syntax.  This works wherever
   397 named facts used to be allowed so far, in proof commands, proof
   398 methods, attributes etc.  Literal facts are retrieved from the context
   399 according to unification of type and term parameters.  For example,
   400 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   401 theorems in the current context, then these are valid literal facts:
   402 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   403 
   404 There is also a proof method "fact" which does the same composition
   405 for explicit goal states, e.g. the following proof texts coincide with
   406 certain special cases of literal facts:
   407 
   408   have "A" by fact                 ==  note `A`
   409   have "A ==> B" by fact           ==  note `A ==> B`
   410   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   411   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   412 
   413 * Isar: ":" (colon) is no longer a symbolic identifier character in
   414 outer syntax.  Thus symbolic identifiers may be used without
   415 additional white space in declarations like this: ``assume *: A''.
   416 
   417 * Isar: 'print_facts' prints all local facts of the current context,
   418 both named and unnamed ones.
   419 
   420 * Isar: 'def' now admits simultaneous definitions, e.g.:
   421 
   422   def x == "t" and y == "u"
   423 
   424 * Isar: added command 'unfolding', which is structurally similar to
   425 'using', but affects both the goal state and facts by unfolding given
   426 rewrite rules.  Thus many occurrences of the 'unfold' method or
   427 'unfolded' attribute may be replaced by first-class proof text.
   428 
   429 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   430 and command 'unfolding' now all support object-level equalities
   431 (potentially conditional).  The underlying notion of rewrite rule is
   432 analogous to the 'rule_format' attribute, but *not* that of the
   433 Simplifier (which is usually more generous).
   434 
   435 * Isar: the new attribute [rotated n] (default n = 1) rotates the
   436 premises of a theorem by n. Useful in conjunction with drule.
   437 
   438 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   439 method expression within a sandbox consisting of the first N
   440 sub-goals, which need to exist.  For example, ``simp_all [3]''
   441 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   442 simplifies all new goals that emerge from applying rule foo to the
   443 originally first one.
   444 
   445 * Isar: schematic goals are no longer restricted to higher-order
   446 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   447 expected.
   448 
   449 * Isar: the conclusion of a long theorem statement is now either
   450 'shows' (a simultaneous conjunction, as before), or 'obtains'
   451 (essentially a disjunction of cases with local parameters and
   452 assumptions).  The latter allows to express general elimination rules
   453 adequately; in this notation common elimination rules look like this:
   454 
   455   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   456     assumes "EX x. P x"
   457     obtains x where "P x"
   458 
   459   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   460     assumes "A & B"
   461     obtains A and B
   462 
   463   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   464     assumes "A | B"
   465     obtains
   466       A
   467     | B
   468 
   469 The subsequent classical rules even refer to the formal "thesis"
   470 explicitly:
   471 
   472   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   473     obtains "~ thesis"
   474 
   475   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   476     obtains "thesis ==> something"
   477 
   478 The actual proof of an 'obtains' statement is analogous to that of the
   479 Isar proof element 'obtain', only that there may be several cases.
   480 Optional case names may be specified in parentheses; these will be
   481 available both in the present proof and as annotations in the
   482 resulting rule, for later use with the 'cases' method (cf. attribute
   483 case_names).
   484 
   485 * Isar: the assumptions of a long theorem statement are available as
   486 "assms" fact in the proof context.  This is more appropriate than the
   487 (historical) "prems", which refers to all assumptions of the current
   488 context, including those from the target locale, proof body etc.
   489 
   490 * Isar: 'print_statement' prints theorems from the current theory or
   491 proof context in long statement form, according to the syntax of a
   492 top-level lemma.
   493 
   494 * Isar: 'obtain' takes an optional case name for the local context
   495 introduction rule (default "that").
   496 
   497 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   498 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   499 to occur.
   500 
   501 * Pure: syntax "CONST name" produces a fully internalized constant
   502 according to the current context.  This is particularly useful for
   503 syntax translations that should refer to internal constant
   504 representations independently of name spaces.
   505 
   506 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   507 instead of "FOO ". This allows multiple binder declarations to coexist
   508 in the same context.  INCOMPATIBILITY.
   509 
   510 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   511 primitive that also works in a locale context (both for constants and
   512 fixed variables). Type declaration and internal syntactic representation
   513 of given constants retrieved from the context. Likewise, the
   514 'no_notation' command allows to remove given syntax annotations from the
   515 current context.
   516 
   517 * Isar/locales: new derived specification elements 'axiomatization',
   518 'definition', 'abbreviation', which support type-inference, admit
   519 object-level specifications (equality, equivalence).  See also the
   520 isar-ref manual.  Examples:
   521 
   522   axiomatization
   523     eq  (infix "===" 50) where
   524     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   525 
   526   definition "f x y = x + y + 1"
   527   definition g where "g x = f x x"
   528 
   529   abbreviation
   530     neq  (infix "=!=" 50) where
   531     "x =!= y == ~ (x === y)"
   532 
   533 These specifications may be also used in a locale context.  Then the
   534 constants being introduced depend on certain fixed parameters, and the
   535 constant name is qualified by the locale base name.  An internal
   536 abbreviation takes care for convenient input and output, making the
   537 parameters implicit and using the original short name.  See also
   538 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   539 entities from a monomorphic theory.
   540 
   541 Presently, abbreviations are only available 'in' a target locale, but
   542 not inherited by general import expressions.  Also note that
   543 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   544 'translations' in common applications.  The "no_abbrevs" print mode
   545 prevents folding of abbreviations in term output.
   546 
   547 Concrete syntax is attached to specified constants in internal form,
   548 independently of name spaces.  The parse tree representation is
   549 slightly different -- use 'notation' instead of raw 'syntax', and
   550 'translations' with explicit "CONST" markup to accommodate this.
   551 
   552 * Pure/Isar: unified syntax for new-style specification mechanisms
   553 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
   554 full type inference and dummy patterns ("_").  For example:
   555 
   556   definition "K x _ = x"
   557 
   558   inductive conj for A B
   559   where "A ==> B ==> conj A B"
   560 
   561 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   562 the current context.  Print mode "no_abbrevs" prevents inversion of
   563 abbreviations on output.
   564 
   565 * Isar/locales: improved parameter handling: use of locales "var" and
   566 "struct" no longer necessary; - parameter renamings are no longer
   567 required to be injective.  For example, this allows to define
   568 endomorphisms as locale endom = homom mult mult h.
   569 
   570 * Isar/locales: changed the way locales with predicates are defined.
   571 Instead of accumulating the specification, the imported expression is
   572 now an interpretation.  INCOMPATIBILITY: different normal form of
   573 locale expressions.  In particular, in interpretations of locales with
   574 predicates, goals repesenting already interpreted fragments are not
   575 removed automatically.  Use methods `intro_locales' and
   576 `unfold_locales'; see below.
   577 
   578 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   579 provide backward reasoning on locales predicates.  The methods are
   580 aware of interpretations and discharge corresponding goals.
   581 `intro_locales' is less aggressive then `unfold_locales' and does not
   582 unfold predicates to assumptions.
   583 
   584 * Isar/locales: the order in which locale fragments are accumulated
   585 has changed.  This enables to override declarations from fragments due
   586 to interpretations -- for example, unwanted simp rules.
   587 
   588 * Isar/locales: interpretation in theories and proof contexts has been
   589 extended.  One may now specify (and prove) equations, which are
   590 unfolded in interpreted theorems.  This is useful for replacing
   591 defined concepts (constants depending on locale parameters) by
   592 concepts already existing in the target context.  Example:
   593 
   594   interpretation partial_order ["op <= :: [int, int] => bool"]
   595     where "partial_order.less (op <=) (x::int) y = (x < y)"
   596 
   597 Typically, the constant `partial_order.less' is created by a
   598 definition specification element in the context of locale
   599 partial_order.
   600 
   601 * Method "induct": improved internal context management to support
   602 local fixes and defines on-the-fly. Thus explicit meta-level
   603 connectives !!  and ==> are rarely required anymore in inductive goals
   604 (using object-logic connectives for this purpose has been long
   605 obsolete anyway). Common proof patterns are explained in
   606 src/HOL/Induct/Common_Patterns.thy, see also
   607 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
   608 examples.
   609 
   610 * Method "induct": improved handling of simultaneous goals. Instead of
   611 introducing object-level conjunction, the statement is now split into
   612 several conclusions, while the corresponding symbolic cases are nested
   613 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
   614 see src/HOL/Induct/Common_Patterns.thy, for example.
   615 
   616 * Method "induct": mutual induction rules are now specified as a list
   617 of rule sharing the same induction cases. HOL packages usually provide
   618 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
   619 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
   620 mutual induction rules differently, i.e. like this:
   621 
   622   (induct rule: foo_bar.inducts)
   623   (induct set: foo bar)
   624   (induct pred: foo bar)
   625   (induct type: foo bar)
   626 
   627 The ML function ProjectRule.projections turns old-style rules into the
   628 new format.
   629 
   630 * Method "coinduct": dual of induction, see
   631 src/HOL/Library/Coinductive_List.thy for various examples.
   632 
   633 * Method "cases", "induct", "coinduct": the ``(open)'' option is
   634 considered a legacy feature.
   635 
   636 * Attribute "symmetric" produces result with standardized schematic
   637 variables (index 0).  Potential INCOMPATIBILITY.
   638 
   639 * Simplifier: by default the simplifier trace only shows top level
   640 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   641 default. Thus there is less danger of being flooded by the trace. The
   642 trace indicates where parts have been suppressed.
   643   
   644 * Provers/classical: removed obsolete classical version of elim_format
   645 attribute; classical elim/dest rules are now treated uniformly when
   646 manipulating the claset.
   647 
   648 * Provers/classical: stricter checks to ensure that supplied intro,
   649 dest and elim rules are well-formed; dest and elim rules must have at
   650 least one premise.
   651 
   652 * Provers/classical: attributes dest/elim/intro take an optional
   653 weight argument for the rule (just as the Pure versions).  Weights are
   654 ignored by automated tools, but determine the search order of single
   655 rule steps.
   656 
   657 * Syntax: input syntax now supports dummy variable binding "%_. b",
   658 where the body does not mention the bound variable.  Note that dummy
   659 patterns implicitly depend on their context of bounds, which makes
   660 "{_. _}" match any set comprehension as expected.  Potential
   661 INCOMPATIBILITY -- parse translations need to cope with syntactic
   662 constant "_idtdummy" in the binding position.
   663 
   664 * Syntax: removed obsolete syntactic constant "_K" and its associated
   665 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   666 for example "A -> B" => "Pi A (%_. B)".
   667 
   668 * Pure: 'class_deps' command visualizes the subclass relation, using
   669 the graph browser tool.
   670 
   671 * Pure: 'print_theory' now suppresses certain internal declarations by
   672 default; use '!' option for full details.
   673 
   674 
   675 *** HOL ***
   676 
   677 * Method "metis" proves goals by applying the Metis general-purpose
   678 resolution prover (see also http://gilith.com/software/metis/).
   679 Examples are in the directory MetisExamples.  WARNING: the
   680 Isabelle/HOL-Metis integration does not yet work properly with
   681 multi-threading.
   682   
   683 * Command 'sledgehammer' invokes external automatic theorem provers as
   684 background processes.  It generates calls to the "metis" method if
   685 successful. These can be pasted into the proof.  Users do not have to
   686 wait for the automatic provers to return.  WARNING: does not really
   687 work with multi-threading.
   688 
   689 * New "auto_quickcheck" feature tests outermost goal statements for
   690 potential counter-examples.  Controlled by ML references
   691 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
   692 5000 milliseconds).  Fails silently if statements is outside of
   693 executable fragment, or any other codgenerator problem occurs.
   694 
   695 * New constant "undefined" with axiom "undefined x = undefined".
   696 
   697 * Added class "HOL.eq", allowing for code generation with polymorphic
   698 equality.
   699 
   700 * Some renaming of class constants due to canonical name prefixing in
   701 the new 'class' package:
   702 
   703     HOL.abs ~> HOL.abs_class.abs
   704     HOL.divide ~> HOL.divide_class.divide
   705     0 ~> HOL.zero_class.zero
   706     1 ~> HOL.one_class.one
   707     op + ~> HOL.plus_class.plus
   708     op - ~> HOL.minus_class.minus
   709     uminus ~> HOL.minus_class.uminus
   710     op * ~> HOL.times_class.times
   711     op < ~> HOL.ord_class.less
   712     op <= > HOL.ord_class.less_eq
   713     Nat.power ~> Power.power_class.power
   714     Nat.size ~> Nat.size_class.size
   715     Numeral.number_of ~> Numeral.number_class.number_of
   716     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
   717     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
   718     Orderings.min ~> Orderings.ord_class.min
   719     Orderings.max ~> Orderings.ord_class.max
   720     Divides.op div ~> Divides.div_class.div
   721     Divides.op mod ~> Divides.div_class.mod
   722     Divides.op dvd ~> Divides.div_class.dvd
   723 
   724 INCOMPATIBILITY.  Adaptions may be required in the following cases:
   725 
   726 a) User-defined constants using any of the names "plus", "minus",
   727 "times", "less" or "less_eq". The standard syntax translations for
   728 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
   729 names.
   730 
   731 b) Variables named "plus", "minus", "times", "less", "less_eq"
   732 INCOMPATIBILITY: use more specific names.
   733 
   734 c) Permutative equations (e.g. "a + b = b + a")
   735 Since the change of names also changes the order of terms, permutative
   736 rewrite rules may get applied in a different order. Experience shows
   737 that this is rarely the case (only two adaptions in the whole Isabelle
   738 distribution).  INCOMPATIBILITY: rewrite proofs
   739 
   740 d) ML code directly refering to constant names
   741 This in general only affects hand-written proof tactics, simprocs and
   742 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
   743 Consider using @{const_name} antiquotation.
   744 
   745 * New class "default" with associated constant "default".
   746 
   747 * Function "sgn" is now overloaded and available on int, real, complex
   748 (and other numeric types), using class "sgn".  Two possible defs of
   749 sgn are given as equational assumptions in the classes sgn_if and
   750 sgn_div_norm; ordered_idom now also inherits from sgn_if.
   751 INCOMPATIBILITY.
   752 
   753 * Locale "partial_order" now unified with class "order" (cf. theory
   754 Orderings), added parameter "less".  INCOMPATIBILITY.
   755 
   756 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
   757 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
   758 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
   759 
   760 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
   761 changed order of proof goals in instance proofs.
   762 
   763 * The transitivity reasoner for partial and linear orders is set up
   764 for classes "order" and "linorder".  Instances of the reasoner are available
   765 in all contexts importing or interpreting the corresponding locales.
   766 Method "order" invokes the reasoner separately; the reasoner
   767 is also integrated with the Simplifier as a solver.  Diagnostic
   768 command 'print_orders' shows the available instances of the reasoner
   769 in the current context.
   770 
   771 * Localized monotonicity predicate in theory "Orderings"; integrated
   772 lemmas max_of_mono and min_of_mono with this predicate.
   773 INCOMPATIBILITY.
   774 
   775 * Formulation of theorem "dense" changed slightly due to integration
   776 with new class dense_linear_order.
   777 
   778 * Uniform lattice theory development in HOL.
   779 
   780     constants "meet" and "join" now named "inf" and "sup"
   781     constant "Meet" now named "Inf"
   782 
   783     classes "meet_semilorder" and "join_semilorder" now named
   784       "lower_semilattice" and "upper_semilattice"
   785     class "lorder" now named "lattice"
   786     class "comp_lat" now named "complete_lattice"
   787 
   788     Instantiation of lattice classes allows explicit definitions
   789     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
   790 
   791   INCOMPATIBILITY.  Theorem renames:
   792 
   793     meet_left_le            ~> inf_le1
   794     meet_right_le           ~> inf_le2
   795     join_left_le            ~> sup_ge1
   796     join_right_le           ~> sup_ge2
   797     meet_join_le            ~> inf_sup_ord
   798     le_meetI                ~> le_infI
   799     join_leI                ~> le_supI
   800     le_meet                 ~> le_inf_iff
   801     le_join                 ~> ge_sup_conv
   802     meet_idempotent         ~> inf_idem
   803     join_idempotent         ~> sup_idem
   804     meet_comm               ~> inf_commute
   805     join_comm               ~> sup_commute
   806     meet_leI1               ~> le_infI1
   807     meet_leI2               ~> le_infI2
   808     le_joinI1               ~> le_supI1
   809     le_joinI2               ~> le_supI2
   810     meet_assoc              ~> inf_assoc
   811     join_assoc              ~> sup_assoc
   812     meet_left_comm          ~> inf_left_commute
   813     meet_left_idempotent    ~> inf_left_idem
   814     join_left_comm          ~> sup_left_commute
   815     join_left_idempotent    ~> sup_left_idem
   816     meet_aci                ~> inf_aci
   817     join_aci                ~> sup_aci
   818     le_def_meet             ~> le_iff_inf
   819     le_def_join             ~> le_iff_sup
   820     join_absorp2            ~> sup_absorb2
   821     join_absorp1            ~> sup_absorb1
   822     meet_absorp1            ~> inf_absorb1
   823     meet_absorp2            ~> inf_absorb2
   824     meet_join_absorp        ~> inf_sup_absorb
   825     join_meet_absorp        ~> sup_inf_absorb
   826     distrib_join_le         ~> distrib_sup_le
   827     distrib_meet_le         ~> distrib_inf_le
   828 
   829     add_meet_distrib_left   ~> add_inf_distrib_left
   830     add_join_distrib_left   ~> add_sup_distrib_left
   831     is_join_neg_meet        ~> is_join_neg_inf
   832     is_meet_neg_join        ~> is_meet_neg_sup
   833     add_meet_distrib_right  ~> add_inf_distrib_right
   834     add_join_distrib_right  ~> add_sup_distrib_right
   835     add_meet_join_distribs  ~> add_sup_inf_distribs
   836     join_eq_neg_meet        ~> sup_eq_neg_inf
   837     meet_eq_neg_join        ~> inf_eq_neg_sup
   838     add_eq_meet_join        ~> add_eq_inf_sup
   839     meet_0_imp_0            ~> inf_0_imp_0
   840     join_0_imp_0            ~> sup_0_imp_0
   841     meet_0_eq_0             ~> inf_0_eq_0
   842     join_0_eq_0             ~> sup_0_eq_0
   843     neg_meet_eq_join        ~> neg_inf_eq_sup
   844     neg_join_eq_meet        ~> neg_sup_eq_inf
   845     join_eq_if              ~> sup_eq_if
   846 
   847     mono_meet               ~> mono_inf
   848     mono_join               ~> mono_sup
   849     meet_bool_eq            ~> inf_bool_eq
   850     join_bool_eq            ~> sup_bool_eq
   851     meet_fun_eq             ~> inf_fun_eq
   852     join_fun_eq             ~> sup_fun_eq
   853     meet_set_eq             ~> inf_set_eq
   854     join_set_eq             ~> sup_set_eq
   855     meet1_iff               ~> inf1_iff
   856     meet2_iff               ~> inf2_iff
   857     meet1I                  ~> inf1I
   858     meet2I                  ~> inf2I
   859     meet1D1                 ~> inf1D1
   860     meet2D1                 ~> inf2D1
   861     meet1D2                 ~> inf1D2
   862     meet2D2                 ~> inf2D2
   863     meet1E                  ~> inf1E
   864     meet2E                  ~> inf2E
   865     join1_iff               ~> sup1_iff
   866     join2_iff               ~> sup2_iff
   867     join1I1                 ~> sup1I1
   868     join2I1                 ~> sup2I1
   869     join1I1                 ~> sup1I1
   870     join2I2                 ~> sup1I2
   871     join1CI                 ~> sup1CI
   872     join2CI                 ~> sup2CI
   873     join1E                  ~> sup1E
   874     join2E                  ~> sup2E
   875 
   876     is_meet_Meet            ~> is_meet_Inf
   877     Meet_bool_def           ~> Inf_bool_def
   878     Meet_fun_def            ~> Inf_fun_def
   879     Meet_greatest           ~> Inf_greatest
   880     Meet_lower              ~> Inf_lower
   881     Meet_set_def            ~> Inf_set_def
   882 
   883     Sup_def                 ~> Sup_Inf
   884     Sup_bool_eq             ~> Sup_bool_def
   885     Sup_fun_eq              ~> Sup_fun_def
   886     Sup_set_eq              ~> Sup_set_def
   887 
   888     listsp_meetI            ~> listsp_infI
   889     listsp_meet_eq          ~> listsp_inf_eq
   890 
   891     meet_min                ~> inf_min
   892     join_max                ~> sup_max
   893 
   894 * Added syntactic class "size"; overloaded constant "size" now has
   895 type "'a::size ==> bool"
   896 
   897 * Internal reorganisation of `size' of datatypes: size theorems
   898 "foo.size" are no longer subsumed by "foo.simps" (but are still
   899 simplification rules by default!); theorems "prod.size" now named
   900 "*.size".
   901 
   902 * Class "div" now inherits from class "times" rather than "type".
   903 INCOMPATIBILITY.
   904 
   905 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
   906 Linorder etc.  have disappeared; operations defined in terms of
   907 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
   908 
   909 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
   910 
   911 * HOL-Word: New extensive library and type for generic, fixed size
   912 machine words, with arithemtic, bit-wise, shifting and rotating
   913 operations, reflection into int, nat, and bool lists, automation for
   914 linear arithmetic (by automatic reflection into nat or int), including
   915 lemmas on overflow and monotonicity.  Instantiated to all appropriate
   916 arithmetic type classes, supporting automatic simplification of
   917 numerals on all operations.
   918 
   919 * Library/Boolean_Algebra: locales for abstract boolean algebras.
   920 
   921 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
   922 
   923 * Code generator library theories:
   924   - Code_Integer represents HOL integers by big integer literals in target
   925     languages.
   926   - Code_Char represents HOL characters by character literals in target
   927     languages.
   928   - Code_Char_chr like Code_Char, but also offers treatment of character
   929     codes; includes Code_Integer.
   930   - Executable_Set allows to generate code for finite sets using lists.
   931   - Executable_Rat implements rational numbers as triples (sign, enumerator,
   932     denominator).
   933   - Executable_Real implements a subset of real numbers, namly those
   934     representable by rational numbers.
   935   - Efficient_Nat implements natural numbers by integers, which in general will
   936     result in higher efficency; pattern matching with 0/Suc is eliminated;
   937     includes Code_Integer.
   938   - Code_Index provides an additional datatype index which is mapped to
   939     target-language built-in integers.
   940   - Code_Message provides an additional datatype message_string} which is isomorphic to
   941     strings; messages are mapped to target-language strings.
   942 
   943 * New package for inductive predicates
   944 
   945   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
   946 
   947     inductive
   948       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   949       for z_1 :: U_1 and ... and z_n :: U_m
   950     where
   951       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   952     | ...
   953 
   954   with full support for type-inference, rather than
   955 
   956     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   957 
   958     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   959     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   960 
   961     inductive "s z_1 ... z_m"
   962     intros
   963       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   964       ...
   965 
   966   For backward compatibility, there is a wrapper allowing inductive
   967   sets to be defined with the new package via
   968 
   969     inductive_set
   970       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   971       for z_1 :: U_1 and ... and z_n :: U_m
   972     where
   973       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   974     | ...
   975 
   976   or
   977 
   978     inductive_set
   979       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   980       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   981       for z_1 :: U_1 and ... and z_n :: U_m
   982     where
   983       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   984     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   985     | ...
   986 
   987   if the additional syntax "p ..." is required.
   988 
   989   Numerous examples can be found in the subdirectories src/HOL/Auth,
   990   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
   991 
   992   INCOMPATIBILITIES:
   993 
   994   - Since declaration and definition of inductive sets or predicates
   995     is no longer separated, abbreviations involving the newly
   996     introduced sets or predicates must be specified together with the
   997     introduction rules after the 'where' keyword (see above), rather
   998     than before the actual inductive definition.
   999 
  1000   - The variables in induction and elimination rules are now
  1001     quantified in the order of their occurrence in the introduction
  1002     rules, rather than in alphabetical order. Since this may break
  1003     some proofs, these proofs either have to be repaired, e.g. by
  1004     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1005     statements of the form
  1006 
  1007       case (rule_i a_i_1 ... a_i_{k_i})
  1008 
  1009     or the old order of quantification has to be restored by explicitly adding
  1010     meta-level quantifiers in the introduction rules, i.e.
  1011 
  1012       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1013 
  1014   - The format of the elimination rules is now
  1015 
  1016       p z_1 ... z_m x_1 ... x_n ==>
  1017         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1018         ==> ... ==> P
  1019 
  1020     for predicates and
  1021 
  1022       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1023         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1024         ==> ... ==> P
  1025 
  1026     for sets rather than
  1027 
  1028       x : s z_1 ... z_m ==>
  1029         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1030         ==> ... ==> P
  1031 
  1032     This may require terms in goals to be expanded to n-tuples
  1033     (e.g. using case_tac or simplification with the split_paired_all
  1034     rule) before the above elimination rule is applicable.
  1035 
  1036   - The elimination or case analysis rules for (mutually) inductive
  1037     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1038     list of rules "p_1_..._p_k.elims" is no longer available.
  1039 
  1040 * New package "function"/"fun" for general recursive functions,
  1041 supporting mutual and nested recursion, definitions in local contexts,
  1042 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1043 for small examples, and the separate tutorial on the function
  1044 package. The old recdef "package" is still available as before, but
  1045 users are encouraged to use the new package.
  1046 
  1047 * Method "lexicographic_order" automatically synthesizes termination
  1048 relations as lexicographic combinations of size measures. 
  1049 
  1050 * Case-expressions allow arbitrary constructor-patterns (including
  1051 "_") and take their order into account, like in functional
  1052 programming.  Internally, this is translated into nested
  1053 case-expressions; missing cases are added and mapped to the predefined
  1054 constant "undefined". In complicated cases printing may no longer show
  1055 the original input but the internal form. Lambda-abstractions allow
  1056 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1057 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1058 variable.
  1059 
  1060 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1061 is an abbreviation for "of_nat :: nat => int". The simplification
  1062 rules for "of_nat" have been changed to work like "int" did
  1063 previously.  Potential INCOMPATIBILITY:
  1064   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1065   - of_nat_diff and of_nat_mult are no longer default simp rules
  1066 
  1067 * Method "algebra" solves polynomial equations over (semi)rings using
  1068 Groebner bases. The (semi)ring structure is defined by locales and the
  1069 tool setup depends on that generic context. Installing the method for
  1070 a specific type involves instantiating the locale and possibly adding
  1071 declarations for computation on the coefficients.  The method is
  1072 already instantiated for natural numbers and for the axiomatic class
  1073 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1074 CALCULEMUS 2007 for the general principles underlying this
  1075 architecture of context-aware proof-tools.
  1076 
  1077 * Method "ferrack" implements quantifier elimination over
  1078 special-purpose dense linear orders using locales (analogous to
  1079 "algebra"). The method is already installed for class
  1080 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1081 rat, etc.
  1082 
  1083 * Former constant "List.op @" now named "List.append".  Use ML
  1084 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1085 circumvent possible incompatibilities when working on ML level.
  1086 
  1087 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1088 
  1089 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1090 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1091 
  1092 * New syntax for Haskell-like list comprehension (input only), eg.
  1093 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1094 
  1095 * The special syntax for function "filter" has changed from [x :
  1096 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1097 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1098 
  1099 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1100 defined on nat only, as an abbreviation for [a..<Suc b]
  1101 INCOMPATIBILITY.
  1102 
  1103 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1104 
  1105 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1106 
  1107 * New lemma collection field_simps (an extension of ring_simps) for
  1108 manipulating (in)equations involving division. Multiplies with all
  1109 denominators that can be proved to be non-zero (in equations) or
  1110 positive/negative (in inequations).
  1111 
  1112 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1113 have been improved and renamed to ring_simps, group_simps and
  1114 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1115 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1116 
  1117 * Theory Library/Commutative_Ring: switched from recdef to function
  1118 package; constants add, mul, pow now curried.  Infix syntax for
  1119 algebraic operations.
  1120 
  1121 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1122 INCOMPATIBILITY.
  1123 
  1124 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1125 INCOMPATIBILITY.
  1126 
  1127 * HOL/records: generalised field-update to take a function on the
  1128 field rather than the new value: r(|A := x|) is translated to A_update
  1129 (K x) r The K-combinator that is internally used is called K_record.
  1130 INCOMPATIBILITY: Usage of the plain update functions has to be
  1131 adapted.
  1132  
  1133 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1134 * x = 0, which are required for a semiring.  Richer structures do not
  1135 inherit from semiring_0 anymore, because this property is a theorem
  1136 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1137 there is more to prove, but this is mostly trivial.
  1138 
  1139 * Class "recpower" is generalized to arbitrary monoids, not just
  1140 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1141 commutativity or semiring properties additionally.
  1142 
  1143 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1144 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1145 better use 'abbreviation'.
  1146 
  1147 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1148 
  1149 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1150 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1151 significant changes for setting up numeral syntax for types:
  1152   - New constants Numeral.pred and Numeral.succ instead
  1153       of former Numeral.bin_pred and Numeral.bin_succ.
  1154   - Use integer operations instead of bin_add, bin_mult and so on.
  1155   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1156   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1157 
  1158 See src/HOL/Integ/IntArith.thy for an example setup.
  1159 
  1160 * Command 'normal_form' computes the normal form of a term that may
  1161 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1162 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1163 heavy-duty computations because the functions are compiled to ML
  1164 first.  Correspondingly, a method "normalization" is provided.  See
  1165 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1166 
  1167 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1168 25 like -->); output depends on the "iff" print_mode, the default is
  1169 "A = B" (with priority 50).
  1170 
  1171 * Relations less (<) and less_eq (<=) are also available on type bool.
  1172 Modified syntax to disallow nesting without explicit parentheses,
  1173 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1174 INCOMPATIBILITY.
  1175 
  1176 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1177 
  1178 * Relation composition operator "op O" now has precedence 75 and binds
  1179 stronger than union and intersection. INCOMPATIBILITY.
  1180 
  1181 * The old set interval syntax "{m..n(}" (and relatives) has been
  1182 removed.  Use "{m..<n}" (and relatives) instead.
  1183 
  1184 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1185 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1186 ``declare [[simproc del: neq]]''.
  1187 
  1188 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1189 True/False.
  1190 
  1191 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1192 
  1193 * Theorem setsum_mult renamed to setsum_right_distrib.
  1194 
  1195 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1196 ``rule'' method.
  1197 
  1198 * Reimplemented methods "sat" and "satx", with several improvements:
  1199 goals no longer need to be stated as "<prems> ==> False", equivalences
  1200 (i.e. "=" on type bool) are handled, variable names of the form
  1201 "lit_<n>" are no longer reserved, significant speedup.
  1202 
  1203 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1204 zChaff is still supported as well.
  1205 
  1206 * 'inductive' and 'datatype': provide projections of mutual rules,
  1207 bundled as foo_bar.inducts;
  1208 
  1209 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1210 Library.
  1211 
  1212 * Library: moved theory Accessible_Part to main HOL.
  1213 
  1214 * Library: added theory Coinductive_List of potentially infinite lists
  1215 as greatest fixed-point.
  1216 
  1217 * Library: added theory AssocList which implements (finite) maps as
  1218 association lists.
  1219 
  1220 * Method "evaluation" solves goals (i.e. a boolean expression)
  1221 efficiently by compiling it to ML.  The goal is "proved" (via an
  1222 oracle) if it evaluates to True.
  1223 
  1224 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1225 also when invoked by the simplifier.  This results in the Simplifier
  1226 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1227 Configuration option fast_arith_split_limit=0 recovers the old
  1228 behavior.
  1229 
  1230 * Support for hex (0x20) and binary (0b1001) numerals.
  1231 
  1232 * New method: reify eqs (t), where eqs are equations for an
  1233 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1234 parameter, computes a term s::'b and a list xs::'a list and proves the
  1235 theorem I xs s = t. This is also known as reification or quoting. The
  1236 resulting theorem is applied to the subgoal to substitute t with I xs
  1237 s.  If t is omitted, the subgoal itself is reified.
  1238 
  1239 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1240 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1241 where f is supposed to be a computable function (in the sense of code
  1242 generattion). The method uses reify to compute s and xs as above then
  1243 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1244 r and finally gets the theorem t = r, which is again applied to the
  1245 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1246 
  1247 * Reflection: Automatic reification now handels binding, an example is
  1248 available in src/HOL/ex/ReflectionEx.thy
  1249 
  1250 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1251 command 'statespace' that is similar to 'record', but introduces an
  1252 abstract specification based on the locale infrastructure instead of
  1253 HOL types.  This leads to extra flexibility in composing state spaces,
  1254 in particular multiple inheritance and renaming of components.
  1255 
  1256 
  1257 *** HOL-Complex ***
  1258 
  1259 * Hyperreal: Functions root and sqrt are now defined on negative real
  1260 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1261 Nonnegativity side conditions have been removed from many lemmas, so
  1262 that more subgoals may now be solved by simplification; potential
  1263 INCOMPATIBILITY.
  1264 
  1265 * Real: new type classes formalize real normed vector spaces and
  1266 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1267 and norm :: 'a => real.
  1268 
  1269 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1270 reals into other types. The overloaded constant Reals :: 'a set is now
  1271 defined as range of_real; potential INCOMPATIBILITY.
  1272 
  1273 * Real: proper support for ML code generation, including 'quickcheck'.
  1274 Reals are implemented as arbitrary precision rationals.
  1275 
  1276 * Hyperreal: Several constants that previously worked only for the
  1277 reals have been generalized, so they now work over arbitrary vector
  1278 spaces. Type annotations may need to be added in some cases; potential
  1279 INCOMPATIBILITY.
  1280 
  1281   Infinitesimal  :: ('a::real_normed_vector) star set
  1282   HFinite        :: ('a::real_normed_vector) star set
  1283   HInfinite      :: ('a::real_normed_vector) star set
  1284   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1285   monad          :: ('a::real_normed_vector) star => 'a star set
  1286   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1287   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1288   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1289   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1290   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1291   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1292   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1293   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1294   sgn            :: 'a::real_normed_vector => 'a
  1295   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1296 
  1297 * Complex: Some complex-specific constants are now abbreviations for
  1298 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1299 hnorm.  Other constants have been entirely removed in favor of the
  1300 polymorphic versions (INCOMPATIBILITY):
  1301 
  1302   approx        <-- capprox
  1303   HFinite       <-- CFinite
  1304   HInfinite     <-- CInfinite
  1305   Infinitesimal <-- CInfinitesimal
  1306   monad         <-- cmonad
  1307   galaxy        <-- cgalaxy
  1308   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1309   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1310   (ns)deriv     <-- (ns)cderiv
  1311 
  1312 
  1313 *** HOL-Algebra ***
  1314 
  1315 * Formalisation of ideals and the quotient construction over rings.
  1316 
  1317 * Order and lattice theory no longer based on records.
  1318 INCOMPATIBILITY.
  1319 
  1320 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1321 greatest_closed.  INCOMPATIBILITY.
  1322 
  1323 * Method algebra is now set up via an attribute.  For examples see
  1324 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1325 of algebraic structures.
  1326 
  1327 * Renamed theory CRing to Ring.
  1328 
  1329 
  1330 *** HOL-Nominal ***
  1331 
  1332 * Substantial, yet incomplete support for nominal datatypes (binding
  1333 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  1334 src/HOL/Nominal/Examples.  Prospective users should consult
  1335 http://isabelle.in.tum.de/nominal/
  1336 
  1337 
  1338 *** ML ***
  1339 
  1340 * ML basics: just one true type int, which coincides with IntInf.int
  1341 (even on SML/NJ).
  1342 
  1343 * ML within Isar: antiquotations allow to embed statically-checked
  1344 formal entities in the source, referring to the context available at
  1345 compile-time.  For example:
  1346 
  1347 ML {* @{sort "{zero,one}"} *}
  1348 ML {* @{typ "'a => 'b"} *}
  1349 ML {* @{term "%x. x"} *}
  1350 ML {* @{prop "x == y"} *}
  1351 ML {* @{ctyp "'a => 'b"} *}
  1352 ML {* @{cterm "%x. x"} *}
  1353 ML {* @{cprop "x == y"} *}
  1354 ML {* @{thm asm_rl} *}
  1355 ML {* @{thms asm_rl} *}
  1356 ML {* @{type_name c} *}
  1357 ML {* @{type_syntax c} *}
  1358 ML {* @{const_name c} *}
  1359 ML {* @{const_syntax c} *}
  1360 ML {* @{context} *}
  1361 ML {* @{theory} *}
  1362 ML {* @{theory Pure} *}
  1363 ML {* @{theory_ref} *}
  1364 ML {* @{theory_ref Pure} *}
  1365 ML {* @{simpset} *}
  1366 ML {* @{claset} *}
  1367 ML {* @{clasimpset} *}
  1368 
  1369 The same works for sources being ``used'' within an Isar context.
  1370 
  1371 * ML in Isar: improved error reporting; extra verbosity with
  1372 ML_Context.trace enabled.
  1373 
  1374 * Pure/General/table.ML: the join operations now works via exceptions
  1375 DUP/SAME instead of type option. This is simpler in simple cases, and
  1376 admits slightly more efficient complex applications.
  1377 
  1378 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1379 use Context.generic instead of just theory.
  1380 
  1381 * Pure: datatype Context.generic joins theory/Proof.context and
  1382 provides some facilities for code that works in either kind of
  1383 context, notably GenericDataFun for uniform theory and proof data.
  1384 
  1385 * Pure: simplified internal attribute type, which is now always
  1386 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  1387 local (Proof.context) attributes have been discontinued, while
  1388 minimizing code duplication. Thm.rule_attribute and
  1389 Thm.declaration_attribute build canonical attributes; see also structure
  1390 Context for further operations on Context.generic, notably
  1391 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  1392 declarations and definitions.
  1393 
  1394 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1395 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1396 init only required for impure data. INCOMPATIBILITY: empty really need
  1397 to be empty (no dependencies on theory content!)
  1398 
  1399 * Pure/kernel: consts certification ignores sort constraints given in
  1400 signature declarations. (This information is not relevant to the
  1401 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  1402 potential INCOMPATIBILITY.
  1403 
  1404 * Pure: axiomatic type classes are now purely definitional, with
  1405 explicit proofs of class axioms and super class relations performed
  1406 internally. See Pure/axclass.ML for the main internal interfaces --
  1407 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1408 AxClass.axiomatize_class/classrel/arity supersede
  1409 Sign.add_classes/classrel/arities.
  1410 
  1411 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1412 global/local versions on theory vs. Proof.context have been
  1413 discontinued; Attrib.syntax and Method.syntax have been adapted
  1414 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1415 attributes, methods, etc.
  1416 
  1417 * Pure: several functions of signature "... -> theory -> theory * ..."
  1418 have been reoriented to "... -> theory -> ... * theory" in order to
  1419 allow natural usage in combination with the ||>, ||>>, |-> and
  1420 fold_map combinators.
  1421 
  1422 * Pure: official theorem names (closed derivations) and additional
  1423 comments (tags) are now strictly separate.  Name hints -- which are
  1424 maintained as tags -- may be attached any time without affecting the
  1425 derivation.
  1426 
  1427 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1428 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1429 achieve the old behaviour.
  1430 
  1431 * Pure: the "Goal" constant is now called "prop", supporting a
  1432 slightly more general idea of ``protecting'' meta-level rule
  1433 statements.
  1434 
  1435 * Pure: Logic.(un)varify only works in a global context, which is now
  1436 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1437 Logic.legacy_(un)varify as temporary workaround.
  1438 
  1439 * Pure: structure Name provides scalable operations for generating
  1440 internal variable names, notably Name.variants etc.  This replaces
  1441 some popular functions from term.ML:
  1442 
  1443   Term.variant		->  Name.variant
  1444   Term.variantlist	->  Name.variant_list
  1445   Term.invent_names	->  Name.invent_list
  1446 
  1447 Note that low-level renaming rarely occurs in new code -- operations
  1448 from structure Variable are used instead (see below).
  1449 
  1450 * Pure: structure Variable provides fundamental operations for proper
  1451 treatment of fixed/schematic variables in a context.  For example,
  1452 Variable.import introduces fixes for schematics of given facts and
  1453 Variable.export reverses the effect (up to renaming) -- this replaces
  1454 various freeze_thaw operations.
  1455 
  1456 * Pure: structure Goal provides simple interfaces for
  1457 init/conclude/finish and tactical prove operations (replacing former
  1458 Tactic.prove).  Goal.prove is the canonical way to prove results
  1459 within a given context; Goal.prove_global is a degraded version for
  1460 theory level goals, including a global Drule.standard.  Note that
  1461 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1462 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1463 in a locale context).
  1464 
  1465 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  1466 and type checking (Syntax.check_term etc.), with common combinations
  1467 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  1468 which are considered legacy and await removal.
  1469 
  1470 * Pure/Syntax: generic interfaces for type unchecking
  1471 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  1472 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  1473 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  1474 available for convenience, but refer to the very same operations using
  1475 a mere theory instead of a full context.
  1476 
  1477 * Isar: simplified treatment of user-level errors, using exception
  1478 ERROR of string uniformly.  Function error now merely raises ERROR,
  1479 without any side effect on output channels.  The Isar toplevel takes
  1480 care of proper display of ERROR exceptions.  ML code may use plain
  1481 handle/can/try; cat_error may be used to concatenate errors like this:
  1482 
  1483   ... handle ERROR msg => cat_error msg "..."
  1484 
  1485 Toplevel ML code (run directly or through the Isar toplevel) may be
  1486 embedded into the Isar toplevel with exception display/debug like
  1487 this:
  1488 
  1489   Isar.toplevel (fn () => ...)
  1490 
  1491 INCOMPATIBILITY, removed special transform_error facilities, removed
  1492 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1493 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1494 -- use plain ERROR instead.
  1495 
  1496 * Isar: theory setup now has type (theory -> theory), instead of a
  1497 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1498 
  1499 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  1500 ProofContext.debug/verbose flags.
  1501 
  1502 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1503 theory before entering a proof state.  Transactions now always see a
  1504 quasi-functional intermediate checkpoint, both in interactive and
  1505 batch mode.
  1506 
  1507 * Isar: simplified interfaces for outer syntax.  Renamed
  1508 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  1509 OuterSyntax.add_parsers -- this functionality is now included in
  1510 OuterSyntax.command etc.  INCOMPATIBILITY.
  1511 
  1512 * Simplifier: the simpset of a running simplification process now
  1513 contains a proof context (cf. Simplifier.the_context), which is the
  1514 very context that the initial simpset has been retrieved from (by
  1515 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1516 (solver, looper etc.) may depend on arbitrary proof data.
  1517 
  1518 * Simplifier.inherit_context inherits the proof context (plus the
  1519 local bounds) of the current simplification process; any simproc
  1520 etc. that calls the Simplifier recursively should do this!  Removed
  1521 former Simplifier.inherit_bounds, which is already included here --
  1522 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1523 specify an explicit context using Simplifier.context/theory_context.
  1524 
  1525 * Simplifier/Classical Reasoner: more abstract interfaces
  1526 change_simpset/claset for modifying the simpset/claset reference of a
  1527 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1528 INCOMPATIBILITY.
  1529 
  1530 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1531 "Trueprop" etc.
  1532 
  1533 
  1534 *** System ***
  1535 
  1536 * settings: the default heap location within ISABELLE_HOME_USER now
  1537 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  1538 Isabelle installations.
  1539 
  1540 * isabelle-process: option -S (secure mode) disables some critical
  1541 operations, notably runtime compilation and evaluation of ML source
  1542 code.
  1543 
  1544 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  1545 
  1546 * Support for parallel execution, using native multicore support of
  1547 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  1548 independent theories, according to the given theory header
  1549 specifications. The maximum number of worker threads is specified via
  1550 usedir option -M or the "max-threads" setting in Proof General. A
  1551 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  1552 to 6 on a 8-core machine.  User-code needs to observe certain
  1553 guidelines for thread-safe programming, see appendix A in the Isar
  1554 Implementation manual.
  1555 
  1556 
  1557 
  1558 New in Isabelle2005 (October 2005)
  1559 ----------------------------------
  1560 
  1561 *** General ***
  1562 
  1563 * Theory headers: the new header syntax for Isar theories is
  1564 
  1565   theory <name>
  1566   imports <theory1> ... <theoryN>
  1567   uses <file1> ... <fileM>
  1568   begin
  1569 
  1570 where the 'uses' part is optional.  The previous syntax
  1571 
  1572   theory <name> = <theory1> + ... + <theoryN>:
  1573 
  1574 will disappear in the next release.  Use isatool fixheaders to convert
  1575 existing theory files.  Note that there is no change in ancient
  1576 non-Isar theories now, but these will disappear soon.
  1577 
  1578 * Theory loader: parent theories can now also be referred to via
  1579 relative and absolute paths.
  1580 
  1581 * Command 'find_theorems' searches for a list of criteria instead of a
  1582 list of constants. Known criteria are: intro, elim, dest, name:string,
  1583 simp:term, and any term. Criteria can be preceded by '-' to select
  1584 theorems that do not match. Intro, elim, dest select theorems that
  1585 match the current goal, name:s selects theorems whose fully qualified
  1586 name contain s, and simp:term selects all simplification rules whose
  1587 lhs match term.  Any other term is interpreted as pattern and selects
  1588 all theorems matching the pattern. Available in ProofGeneral under
  1589 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1590 
  1591   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1592 
  1593 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1594 matching the current goal as introduction rule and not having "HOL."
  1595 in their name (i.e. not being defined in theory HOL).
  1596 
  1597 * Command 'thms_containing' has been discontinued in favour of
  1598 'find_theorems'; INCOMPATIBILITY.
  1599 
  1600 * Communication with Proof General is now 8bit clean, which means that
  1601 Unicode text in UTF-8 encoding may be used within theory texts (both
  1602 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1603 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1604 
  1605   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1606   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1607 
  1608 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1609 Classical Reasoner.  Typical big applications run around 2 times
  1610 faster.
  1611 
  1612 
  1613 *** Document preparation ***
  1614 
  1615 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1616 of raw sources.  Only those symbols that do not require additional
  1617 LaTeX packages (depending on comments in isabellesym.sty) are
  1618 displayed properly, everything else is left verbatim.  isatool display
  1619 and isatool print are used as front ends (these are subject to the
  1620 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1621 
  1622 * Command tags control specific markup of certain regions of text,
  1623 notably folding and hiding.  Predefined tags include "theory" (for
  1624 theory begin and end), "proof" for proof commands, and "ML" for
  1625 commands involving ML code; the additional tags "visible" and
  1626 "invisible" are unused by default.  Users may give explicit tag
  1627 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1628 interpretation of tags is determined by the LaTeX job during document
  1629 preparation: see option -V of isatool usedir, or options -n and -t of
  1630 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1631 \isadroptag.
  1632 
  1633 Several document versions may be produced at the same time via isatool
  1634 usedir (the generated index.html will link all of them).  Typical
  1635 specifications include ''-V document=theory,proof,ML'' to present
  1636 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1637 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1638 these parts without any formal replacement text.  The Isabelle site
  1639 default settings produce ''document'' and ''outline'' versions as
  1640 specified above.
  1641 
  1642 * Several new antiquotations:
  1643 
  1644   @{term_type term} prints a term with its type annotated;
  1645 
  1646   @{typeof term} prints the type of a term;
  1647 
  1648   @{const const} is the same as @{term const}, but checks that the
  1649   argument is a known logical constant;
  1650 
  1651   @{term_style style term} and @{thm_style style thm} print a term or
  1652   theorem applying a "style" to it
  1653 
  1654   @{ML text}
  1655 
  1656 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1657 definitions, equations, inequations etc., 'concl' printing only the
  1658 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1659 to print the specified premise.  TermStyle.add_style provides an ML
  1660 interface for introducing further styles.  See also the "LaTeX Sugar"
  1661 document practical applications.  The ML antiquotation prints
  1662 type-checked ML expressions verbatim.
  1663 
  1664 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1665 and 'text' support optional locale specification '(in loc)', which
  1666 specifies the default context for interpreting antiquotations.  For
  1667 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1668 
  1669 * Option 'locale=NAME' of antiquotations specifies an alternative
  1670 context interpreting the subsequent argument.  For example: @{thm
  1671 [locale=lattice] inf_assoc}.
  1672 
  1673 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1674 a proof context.
  1675 
  1676 * Proper output of antiquotations for theory commands involving a
  1677 proof context (such as 'locale' or 'theorem (in loc) ...').
  1678 
  1679 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1680 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1681 
  1682 * isatool usedir: new option -C (default true) controls whether option
  1683 -D should include a copy of the original document directory; -C false
  1684 prevents unwanted effects such as copying of administrative CVS data.
  1685 
  1686 
  1687 *** Pure ***
  1688 
  1689 * Considerably improved version of 'constdefs' command.  Now performs
  1690 automatic type-inference of declared constants; additional support for
  1691 local structure declarations (cf. locales and HOL records), see also
  1692 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1693 sequential dependencies of definitions within a single 'constdefs'
  1694 section; moreover, the declared name needs to be an identifier.  If
  1695 all fails, consider to fall back on 'consts' and 'defs' separately.
  1696 
  1697 * Improved indexed syntax and implicit structures.  First of all,
  1698 indexed syntax provides a notational device for subscripted
  1699 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1700 expressions.  Secondly, in a local context with structure
  1701 declarations, number indexes \<^sub>n or the empty index (default
  1702 number 1) refer to a certain fixed variable implicitly; option
  1703 show_structs controls printing of implicit structures.  Typical
  1704 applications of these concepts involve record types and locales.
  1705 
  1706 * New command 'no_syntax' removes grammar declarations (and
  1707 translations) resulting from the given syntax specification, which is
  1708 interpreted in the same manner as for the 'syntax' command.
  1709 
  1710 * 'Advanced' translation functions (parse_translation etc.) may depend
  1711 on the signature of the theory context being presently used for
  1712 parsing/printing, see also isar-ref manual.
  1713 
  1714 * Improved 'oracle' command provides a type-safe interface to turn an
  1715 ML expression of type theory -> T -> term into a primitive rule of
  1716 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1717 is already included here); see also FOL/ex/IffExample.thy;
  1718 INCOMPATIBILITY.
  1719 
  1720 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1721 before); "cI" is no longer bound, use "c.intro" instead.
  1722 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1723 axclasses vs. locales.
  1724 
  1725 * Improved internal renaming of symbolic identifiers -- attach primes
  1726 instead of base 26 numbers.
  1727 
  1728 * New flag show_question_marks controls printing of leading question
  1729 marks in schematic variable names.
  1730 
  1731 * In schematic variable names, *any* symbol following \<^isub> or
  1732 \<^isup> is now treated as part of the base name.  For example, the
  1733 following works without printing of awkward ".0" indexes:
  1734 
  1735   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1736     by simp
  1737 
  1738 * Inner syntax includes (*(*nested*) comments*).
  1739 
  1740 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1741 annotations as "(00...)".
  1742 
  1743 * Clear separation of logical types and nonterminals, where the latter
  1744 may only occur in 'syntax' specifications or type abbreviations.
  1745 Before that distinction was only partially implemented via type class
  1746 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1747 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1748 exotic syntax specifications may require further adaption
  1749 (e.g. Cube/Cube.thy).
  1750 
  1751 * Removed obsolete type class "logic", use the top sort {} instead.
  1752 Note that non-logical types should be declared as 'nonterminals'
  1753 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1754 specifications.
  1755 
  1756 * Attributes 'induct' and 'cases': type or set names may now be
  1757 locally fixed variables as well.
  1758 
  1759 * Simplifier: can now control the depth to which conditional rewriting
  1760 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1761 Limit.
  1762 
  1763 * Simplifier: simplification procedures may now take the current
  1764 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1765 interface), which is very useful for calling the Simplifier
  1766 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1767 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1768 low-level mk_simproc no longer applies Logic.varify internally, to
  1769 allow for use in a context of fixed variables.
  1770 
  1771 * thin_tac now works even if the assumption being deleted contains !!
  1772 or ==>.  More generally, erule now works even if the major premise of
  1773 the elimination rule contains !! or ==>.
  1774 
  1775 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1776 
  1777 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1778 from Pure, which contains all common declarations already.  Both
  1779 theories are defined via plain Isabelle/Isar .thy files.
  1780 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1781 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1782 use isatool fixcpure to adapt your theory and ML sources.
  1783 
  1784 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1785 selections of theorems in named facts via index ranges.
  1786 
  1787 * 'print_theorems': in theory mode, really print the difference
  1788 wrt. the last state (works for interactive theory development only),
  1789 in proof mode print all local facts (cf. 'print_facts');
  1790 
  1791 * 'hide': option '(open)' hides only base names.
  1792 
  1793 * More efficient treatment of intermediate checkpoints in interactive
  1794 theory development.
  1795 
  1796 * Code generator is now invoked via code_module (incremental code
  1797 generation) and code_library (modular code generation, ML structures
  1798 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1799 must be quoted when used as identifiers.
  1800 
  1801 * New 'value' command for reading, evaluating and printing terms using
  1802 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1803 quoted when used as identifier.
  1804 
  1805 
  1806 *** Locales ***
  1807 
  1808 * New commands for the interpretation of locale expressions in
  1809 theories (1), locales (2) and proof contexts (3).  These generate
  1810 proof obligations from the expression specification.  After the
  1811 obligations have been discharged, theorems of the expression are added
  1812 to the theory, target locale or proof context.  The synopsis of the
  1813 commands is a follows:
  1814 
  1815   (1) interpretation expr inst
  1816   (2) interpretation target < expr
  1817   (3) interpret expr inst
  1818 
  1819 Interpretation in theories and proof contexts require a parameter
  1820 instantiation of terms from the current context.  This is applied to
  1821 specifications and theorems of the interpreted expression.
  1822 Interpretation in locales only permits parameter renaming through the
  1823 locale expression.  Interpretation is smart in that interpretations
  1824 that are active already do not occur in proof obligations, neither are
  1825 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1826 inspect active interpretations of a particular locale.  For details,
  1827 see the Isar Reference manual.  Examples can be found in
  1828 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1829 
  1830 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1831 'interpret' instead.
  1832 
  1833 * New context element 'constrains' for adding type constraints to
  1834 parameters.
  1835 
  1836 * Context expressions: renaming of parameters with syntax
  1837 redeclaration.
  1838 
  1839 * Locale declaration: 'includes' disallowed.
  1840 
  1841 * Proper static binding of attribute syntax -- i.e. types / terms /
  1842 facts mentioned as arguments are always those of the locale definition
  1843 context, independently of the context of later invocations.  Moreover,
  1844 locale operations (renaming and type / term instantiation) are applied
  1845 to attribute arguments as expected.
  1846 
  1847 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1848 actual attributes; rare situations may require Attrib.attribute to
  1849 embed those attributes into Attrib.src that lack concrete syntax.
  1850 Attribute implementations need to cooperate properly with the static
  1851 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1852 Attrib.XXX_thm etc. already do the right thing without further
  1853 intervention.  Only unusual applications -- such as "where" or "of"
  1854 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1855 on the context and the facts involved -- may have to assign parsed
  1856 values to argument tokens explicitly.
  1857 
  1858 * Changed parameter management in theorem generation for long goal
  1859 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1860 theorem statement in rare situations.
  1861 
  1862 * Locale inspection command 'print_locale' omits notes elements.  Use
  1863 'print_locale!' to have them included in the output.
  1864 
  1865 
  1866 *** Provers ***
  1867 
  1868 * Provers/hypsubst.ML: improved version of the subst method, for
  1869 single-step rewriting: it now works in bound variable contexts. New is
  1870 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1871 rewrite a different subterm than the original subst method, which is
  1872 still available as 'simplesubst'.
  1873 
  1874 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1875 and quasi orders.
  1876 
  1877 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1878 reflexive-transitive closure of relations.
  1879 
  1880 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1881 limit (previously hard-coded with a value of 20) user-definable.
  1882 
  1883 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1884 is peformed already.  Object-logics merely need to finish their
  1885 initial simpset configuration as before.  INCOMPATIBILITY.
  1886 
  1887 
  1888 *** HOL ***
  1889 
  1890 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1891 
  1892   syntax (epsilon)
  1893     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1894 
  1895 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1896 and x-symbol; use option '-m epsilon' to get it actually printed.
  1897 Moreover, the mathematically important symbolic identifier \<epsilon>
  1898 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1899 
  1900 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1901 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1902 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1903 support corresponding Isar calculations.
  1904 
  1905 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1906 instead of ":".
  1907 
  1908 * theory SetInterval: changed the syntax for open intervals:
  1909 
  1910   Old       New
  1911   {..n(}    {..<n}
  1912   {)n..}    {n<..}
  1913   {m..n(}   {m..<n}
  1914   {)m..n}   {m<..n}
  1915   {)m..n(}  {m<..<n}
  1916 
  1917 The old syntax is still supported but will disappear in the next
  1918 release.  For conversion use the following Emacs search and replace
  1919 patterns (these are not perfect but work quite well):
  1920 
  1921   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1922   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1923 
  1924 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1925 equalities in commutative rings; method 'algebra' provides a generic
  1926 interface.
  1927 
  1928 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1929 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1930 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1931 be a tuple pattern.
  1932 
  1933 Some new syntax forms are available:
  1934 
  1935   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1936   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1937   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1938   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1939 
  1940 The latter form "\<Sum>x < k. e" used to be based on a separate
  1941 function "Summation", which has been discontinued.
  1942 
  1943 * theory Finite_Set: in structured induction proofs, the insert case
  1944 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1945 (insert F x)'.
  1946 
  1947 * The 'refute' command has been extended to support a much larger
  1948 fragment of HOL, including axiomatic type classes, constdefs and
  1949 typedefs, inductive datatypes and recursion.
  1950 
  1951 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1952 Requires zChaff with proof generation to be installed.  See
  1953 HOL/ex/SAT_Examples.thy for examples.
  1954 
  1955 * Datatype induction via method 'induct' now preserves the name of the
  1956 induction variable. For example, when proving P(xs::'a list) by
  1957 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1958 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1959 in unstructured proof scripts.
  1960 
  1961 * Reworked implementation of records.  Improved scalability for
  1962 records with many fields, avoiding performance problems for type
  1963 inference. Records are no longer composed of nested field types, but
  1964 of nested extension types. Therefore the record type only grows linear
  1965 in the number of extensions and not in the number of fields.  The
  1966 top-level (users) view on records is preserved.  Potential
  1967 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1968 old record representation. The type generated for a record is called
  1969 <record_name>_ext_type.
  1970 
  1971 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1972 proofs triggered by a record definition or a simproc (if
  1973 quick_and_dirty is enabled).  Definitions of large records can take
  1974 quite long.
  1975 
  1976 New simproc record_upd_simproc for simplification of multiple record
  1977 updates enabled by default.  Moreover, trivial updates are also
  1978 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1979 occasionally, since simplification is more powerful by default.
  1980 
  1981 * typedef: proper support for polymorphic sets, which contain extra
  1982 type-variables in the term.
  1983 
  1984 * Simplifier: automatically reasons about transitivity chains
  1985 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1986 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1987 old proofs break occasionally as simplification may now solve more
  1988 goals than previously.
  1989 
  1990 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1991 present.  Works for all partial orders (class "order"), in particular
  1992 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1993 just like y <= x.
  1994 
  1995 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1996 bound variable or a constant then the let is unfolded.  Otherwise
  1997 first a is simplified to b, and then f b is simplified to g. If
  1998 possible we abstract b from g arriving at "let x = b in h x",
  1999 otherwise we unfold the let and arrive at g.  The simproc can be
  2000 enabled/disabled by the reference use_let_simproc.  Potential
  2001 INCOMPATIBILITY since simplification is more powerful by default.
  2002 
  2003 * Classical reasoning: the meson method now accepts theorems as arguments.
  2004 
  2005 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2006 jobs to provide advice on the provability of subgoals.
  2007 
  2008 * Theory OrderedGroup and Ring_and_Field: various additions and
  2009 improvements to faciliate calculations involving equalities and
  2010 inequalities.
  2011 
  2012 The following theorems have been eliminated or modified
  2013 (INCOMPATIBILITY):
  2014 
  2015   abs_eq             now named abs_of_nonneg
  2016   abs_of_ge_0        now named abs_of_nonneg
  2017   abs_minus_eq       now named abs_of_nonpos
  2018   imp_abs_id         now named abs_of_nonneg
  2019   imp_abs_neg_id     now named abs_of_nonpos
  2020   mult_pos           now named mult_pos_pos
  2021   mult_pos_le        now named mult_nonneg_nonneg
  2022   mult_pos_neg_le    now named mult_nonneg_nonpos
  2023   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2024   mult_neg           now named mult_neg_neg
  2025   mult_neg_le        now named mult_nonpos_nonpos
  2026 
  2027 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2028      
  2029      zero_le_square
  2030      not_square_less_zero 
  2031 
  2032   The following lemmas have been deleted from Real/RealPow:
  2033   
  2034      realpow_zero_zero
  2035      realpow_two
  2036      realpow_less
  2037      zero_le_power
  2038      realpow_two_le
  2039      abs_realpow_two
  2040      realpow_two_abs     
  2041 
  2042 * Theory Parity: added rules for simplifying exponents.
  2043 
  2044 * Theory List:
  2045 
  2046 The following theorems have been eliminated or modified
  2047 (INCOMPATIBILITY):
  2048 
  2049   list_all_Nil       now named list_all.simps(1)
  2050   list_all_Cons      now named list_all.simps(2)
  2051   list_all_conv      now named list_all_iff
  2052   set_mem_eq         now named mem_iff
  2053 
  2054 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2055 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2056 
  2057 
  2058 *** HOL-Complex ***
  2059 
  2060 * Theory RealDef: better support for embedding natural numbers and
  2061 integers in the reals.
  2062 
  2063 The following theorems have been eliminated or modified
  2064 (INCOMPATIBILITY):
  2065 
  2066   exp_ge_add_one_self  now requires no hypotheses
  2067   real_of_int_add      reversed direction of equality (use [symmetric])
  2068   real_of_int_minus    reversed direction of equality (use [symmetric])
  2069   real_of_int_diff     reversed direction of equality (use [symmetric])
  2070   real_of_int_mult     reversed direction of equality (use [symmetric])
  2071 
  2072 * Theory RComplete: expanded support for floor and ceiling functions.
  2073 
  2074 * Theory Ln is new, with properties of the natural logarithm
  2075 
  2076 * Hyperreal: There is a new type constructor "star" for making
  2077 nonstandard types.  The old type names are now type synonyms:
  2078 
  2079   hypreal = real star
  2080   hypnat = nat star
  2081   hcomplex = complex star
  2082 
  2083 * Hyperreal: Many groups of similarly-defined constants have been
  2084 replaced by polymorphic versions (INCOMPATIBILITY):
  2085 
  2086   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2087 
  2088   starset      <-- starsetNat, starsetC
  2089   *s*          <-- *sNat*, *sc*
  2090   starset_n    <-- starsetNat_n, starsetC_n
  2091   *sn*         <-- *sNatn*, *scn*
  2092   InternalSets <-- InternalNatSets, InternalCSets
  2093 
  2094   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2095   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2096   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2097   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2098   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2099 
  2100 * Hyperreal: Many type-specific theorems have been removed in favor of
  2101 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2102 
  2103   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2104   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2105   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2106   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2107   right_minus <-- hypreal_add_minus
  2108   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2109   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2110   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2111   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2112   mult_1_right <-- hcomplex_mult_one_right
  2113   mult_zero_left <-- hcomplex_mult_zero_left
  2114   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2115   right_distrib <-- hypnat_add_mult_distrib2
  2116   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2117   right_inverse <-- hypreal_mult_inverse
  2118   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2119   order_refl <-- {hypreal,hypnat}_le_refl
  2120   order_trans <-- {hypreal,hypnat}_le_trans
  2121   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2122   order_less_le <-- {hypreal,hypnat}_less_le
  2123   linorder_linear <-- {hypreal,hypnat}_le_linear
  2124   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2125   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2126   add_nonneg_nonneg <-- hypreal_le_add_order
  2127 
  2128 * Hyperreal: Separate theorems having to do with type-specific
  2129 versions of constants have been merged into theorems that apply to the
  2130 new polymorphic constants (INCOMPATIBILITY):
  2131 
  2132   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2133   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2134   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2135   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2136   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2137   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2138   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2139   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2140   STAR_diff <-- {STAR,STARC}_diff
  2141   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2142     STARC_hcomplex_of_complex}_image_subset
  2143   starset_n_Un <-- starset{Nat,C}_n_Un
  2144   starset_n_Int <-- starset{Nat,C}_n_Int
  2145   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2146   starset_n_diff <-- starset{Nat,C}_n_diff
  2147   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2148   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2149   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2150   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2151   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2152   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2153   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2154   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2155   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2156   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2157   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2158   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2159   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2160   starfun_diff <-- starfun{C,RC,CR}_diff
  2161   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2162   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2163   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2164   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2165   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2166   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2167   starfun_Id <-- starfunC_Id
  2168   starfun_approx <-- starfun{Nat,CR}_approx
  2169   starfun_capprox <-- starfun{C,RC}_capprox
  2170   starfun_abs <-- starfunNat_rabs
  2171   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2172   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2173   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2174   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2175   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2176   starfun_add_approx <-- starfunCR_add_approx
  2177   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2178   starfun_divide <-- starfun{C,CR,RC}_divide
  2179   starfun_n <-- starfun{Nat,C}_n
  2180   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2181   starfun_n_add <-- starfun{Nat,C}_n_add
  2182   starfun_n_add_minus <-- starfunNat_n_add_minus
  2183   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2184   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2185   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2186 
  2187   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2188   star_n_minus <-- {hypreal,hcomplex}_minus
  2189   star_n_diff <-- {hypreal,hcomplex}_diff
  2190   star_n_mult <-- {hypreal,hcomplex}_mult
  2191   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2192   star_n_le <-- {hypreal,hypnat}_le
  2193   star_n_less <-- {hypreal,hypnat}_less
  2194   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2195   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2196   star_n_abs <-- hypreal_hrabs
  2197   star_n_divide <-- hcomplex_divide
  2198 
  2199   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2200   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2201   star_of_diff <-- hypreal_of_real_diff
  2202   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2203   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2204   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2205   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2206   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2207   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2208   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2209   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2210   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2211   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2212   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2213   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2214   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2215   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2216   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2217   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2218   star_of_power <-- hypreal_of_real_power
  2219   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2220 
  2221 * Hyperreal: new method "transfer" that implements the transfer
  2222 principle of nonstandard analysis. With a subgoal that mentions
  2223 nonstandard types like "'a star", the command "apply transfer"
  2224 replaces it with an equivalent one that mentions only standard types.
  2225 To be successful, all free variables must have standard types; non-
  2226 standard variables must have explicit universal quantifiers.
  2227 
  2228 * Hyperreal: A theory of Taylor series.
  2229 
  2230 
  2231 *** HOLCF ***
  2232 
  2233 * Discontinued special version of 'constdefs' (which used to support
  2234 continuous functions) in favor of the general Pure one with full
  2235 type-inference.
  2236 
  2237 * New simplification procedure for solving continuity conditions; it
  2238 is much faster on terms with many nested lambda abstractions (cubic
  2239 instead of exponential time).
  2240 
  2241 * New syntax for domain package: selector names are now optional.
  2242 Parentheses should be omitted unless argument is lazy, for example:
  2243 
  2244   domain 'a stream = cons "'a" (lazy "'a stream")
  2245 
  2246 * New command 'fixrec' for defining recursive functions with pattern
  2247 matching; defining multiple functions with mutual recursion is also
  2248 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2249 sinr, or any data constructor defined by the domain package. The given
  2250 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2251 syntax and examples.
  2252 
  2253 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2254 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2255 but the proof obligation additionally includes an admissibility
  2256 requirement. The packages generate instances of class cpo or pcpo,
  2257 with continuity and strictness theorems for Rep and Abs.
  2258 
  2259 * HOLCF: Many theorems have been renamed according to a more standard naming
  2260 scheme (INCOMPATIBILITY):
  2261 
  2262   foo_inject:  "foo$x = foo$y ==> x = y"
  2263   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2264   foo_less:    "(foo$x << foo$y) = (x << y)"
  2265   foo_strict:  "foo$UU = UU"
  2266   foo_defined: "... ==> foo$x ~= UU"
  2267   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2268 
  2269 
  2270 *** ZF ***
  2271 
  2272 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2273 including the First Isomorphism Theorem (on quotienting by the kernel
  2274 of a homomorphism).
  2275 
  2276 * ZF/Simplifier: install second copy of type solver that actually
  2277 makes use of TC rules declared to Isar proof contexts (or locales);
  2278 the old version is still required for ML proof scripts.
  2279 
  2280 
  2281 *** Cube ***
  2282 
  2283 * Converted to Isar theory format; use locales instead of axiomatic
  2284 theories.
  2285 
  2286 
  2287 *** ML ***
  2288 
  2289 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2290 for ||>, ||>>, |>>,
  2291 
  2292 * Pure/library.ML no longer defines its own option datatype, but uses
  2293 that of the SML basis, which has constructors NONE and SOME instead of
  2294 None and Some, as well as exception Option.Option instead of OPTION.
  2295 The functions the, if_none, is_some, is_none have been adapted
  2296 accordingly, while Option.map replaces apsome.
  2297 
  2298 * Pure/library.ML: the exception LIST has been given up in favour of
  2299 the standard exceptions Empty and Subscript, as well as
  2300 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2301 superceded by the standard hd and tl functions etc.
  2302 
  2303 A number of basic list functions are no longer exported to the ML
  2304 toplevel, as they are variants of predefined functions.  The following
  2305 suggests how one can translate existing code:
  2306 
  2307     rev_append xs ys = List.revAppend (xs, ys)
  2308     nth_elem (i, xs) = List.nth (xs, i)
  2309     last_elem xs = List.last xs
  2310     flat xss = List.concat xss
  2311     seq fs = List.app fs
  2312     partition P xs = List.partition P xs
  2313     mapfilter f xs = List.mapPartial f xs
  2314 
  2315 * Pure/library.ML: several combinators for linear functional
  2316 transformations, notably reverse application and composition:
  2317 
  2318   x |> f                f #> g
  2319   (x, y) |-> f          f #-> g
  2320 
  2321 * Pure/library.ML: introduced/changed precedence of infix operators:
  2322 
  2323   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2324   infix 2 ?;
  2325   infix 3 o oo ooo oooo;
  2326   infix 4 ~~ upto downto;
  2327 
  2328 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2329 infix operators.
  2330 
  2331 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2332 fold_map support linear functional transformations and nesting.  For
  2333 example:
  2334 
  2335   fold f [x1, ..., xN] y =
  2336     y |> f x1 |> ... |> f xN
  2337 
  2338   (fold o fold) f [xs1, ..., xsN] y =
  2339     y |> fold f xs1 |> ... |> fold f xsN
  2340 
  2341   fold f [x1, ..., xN] =
  2342     f x1 #> ... #> f xN
  2343 
  2344   (fold o fold) f [xs1, ..., xsN] =
  2345     fold f xs1 #> ... #> fold f xsN
  2346 
  2347 * Pure/library.ML: the following selectors on type 'a option are
  2348 available:
  2349 
  2350   the:               'a option -> 'a  (*partial*)
  2351   these:             'a option -> 'a  where 'a = 'b list
  2352   the_default: 'a -> 'a option -> 'a
  2353   the_list:          'a option -> 'a list
  2354 
  2355 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2356 basic operations for association lists, following natural argument
  2357 order; moreover the explicit equality predicate passed here avoids
  2358 potentially expensive polymorphic runtime equality checks.
  2359 The old functions may be expressed as follows:
  2360 
  2361   assoc = uncurry (AList.lookup (op =))
  2362   assocs = these oo AList.lookup (op =)
  2363   overwrite = uncurry (AList.update (op =)) o swap
  2364 
  2365 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2366 
  2367   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2368   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2369 
  2370 replacing make_keylist and keyfilter (occassionally used)
  2371 Naive rewrites:
  2372 
  2373   make_keylist = AList.make
  2374   keyfilter = AList.find (op =)
  2375 
  2376 * eq_fst and eq_snd now take explicit equality parameter, thus
  2377   avoiding eqtypes. Naive rewrites:
  2378 
  2379     eq_fst = eq_fst (op =)
  2380     eq_snd = eq_snd (op =)
  2381 
  2382 * Removed deprecated apl and apr (rarely used).
  2383   Naive rewrites:
  2384 
  2385     apl (n, op) =>>= curry op n
  2386     apr (op, m) =>>= fn n => op (n, m)
  2387 
  2388 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2389 provides a reasonably efficient light-weight implementation of sets as
  2390 lists.
  2391 
  2392 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2393 few new operations; existing lookup and update are now curried to
  2394 follow natural argument order (for use with fold etc.);
  2395 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2396 
  2397 * Pure/General: output via the Isabelle channels of
  2398 writeln/warning/error etc. is now passed through Output.output, with a
  2399 hook for arbitrary transformations depending on the print_mode
  2400 (cf. Output.add_mode -- the first active mode that provides a output
  2401 function wins).  Already formatted output may be embedded into further
  2402 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2403 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2404 accommodate easy composition of diagnostic messages etc.  Programmers
  2405 rarely need to care about Output.output or Output.raw at all, with
  2406 some notable exceptions: Output.output is required when bypassing the
  2407 standard channels (writeln etc.), or in token translations to produce
  2408 properly formatted results; Output.raw is required when capturing
  2409 already output material that will eventually be presented to the user
  2410 a second time.  For the default print mode, both Output.output and
  2411 Output.raw have no effect.
  2412 
  2413 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2414 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2415 cumulative results are displayed at the end of a batch session.
  2416 
  2417 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2418 replaced by File.platform_path and File.shell_path (with appropriate
  2419 hooks).  This provides a clean interface for unusual systems where the
  2420 internal and external process view of file names are different.
  2421 
  2422 * Pure: more efficient orders for basic syntactic entities: added
  2423 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2424 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2425 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2426 orders now -- potential INCOMPATIBILITY for code that depends on a
  2427 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2428 Library.sort_strings on result).
  2429 
  2430 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2431 fold_types traverse types/terms from left to right, observing natural
  2432 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2433 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2434 
  2435 * Pure: name spaces have been refined, with significant changes of the
  2436 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2437 to extern(_table).  The plain name entry path is superceded by a
  2438 general 'naming' context, which also includes the 'policy' to produce
  2439 a fully qualified name and external accesses of a fully qualified
  2440 name; NameSpace.extend is superceded by context dependent
  2441 Sign.declare_name.  Several theory and proof context operations modify
  2442 the naming context.  Especially note Theory.restore_naming and
  2443 ProofContext.restore_naming to get back to a sane state; note that
  2444 Theory.add_path is no longer sufficient to recover from
  2445 Theory.absolute_path in particular.
  2446 
  2447 * Pure: new flags short_names (default false) and unique_names
  2448 (default true) for controlling output of qualified names.  If
  2449 short_names is set, names are printed unqualified.  If unique_names is
  2450 reset, the name prefix is reduced to the minimum required to achieve
  2451 the original result when interning again, even if there is an overlap
  2452 with earlier declarations.
  2453 
  2454 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2455 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2456 (useful for printing error messages).  INCOMPATIBILITY.
  2457 
  2458 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2459 Theory.theory are now identified, referring to the universal
  2460 Context.theory (see Pure/context.ML).  Actual signature and theory
  2461 content is managed as theory data.  The old code and interfaces were
  2462 spread over many files and structures; the new arrangement introduces
  2463 considerable INCOMPATIBILITY to gain more clarity:
  2464 
  2465   Context -- theory management operations (name, identity, inclusion,
  2466     parents, ancestors, merge, etc.), plus generic theory data;
  2467 
  2468   Sign -- logical signature and syntax operations (declaring consts,
  2469     types, etc.), plus certify/read for common entities;
  2470 
  2471   Theory -- logical theory operations (stating axioms, definitions,
  2472     oracles), plus a copy of logical signature operations (consts,
  2473     types, etc.); also a few basic management operations (Theory.copy,
  2474     Theory.merge, etc.)
  2475 
  2476 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2477 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2478 for convenience -- they merely return the theory.
  2479 
  2480 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2481 
  2482 * Pure: the Isar proof context type is already defined early in Pure
  2483 as Context.proof (note that ProofContext.context and Proof.context are
  2484 aliases, where the latter is the preferred name).  This enables other
  2485 Isabelle components to refer to that type even before Isar is present.
  2486 
  2487 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2488 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2489 any of these kinds.  For example, Sign.intern typeK is now
  2490 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2491 Theory.hide_types.  Also note that former
  2492 Theory.hide_classes/types/consts are now
  2493 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2494 internalize their arguments!  INCOMPATIBILITY.
  2495 
  2496 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2497 datatype thmref (with constructors Name and NameSelection) instead of
  2498 plain string -- INCOMPATIBILITY;
  2499 
  2500 * Pure: cases produced by proof methods specify options, where NONE
  2501 means to remove case bindings -- INCOMPATIBILITY in
  2502 (RAW_)METHOD_CASES.
  2503 
  2504 * Pure: the following operations retrieve axioms or theorems from a
  2505 theory node or theory hierarchy, respectively:
  2506 
  2507   Theory.axioms_of: theory -> (string * term) list
  2508   Theory.all_axioms_of: theory -> (string * term) list
  2509   PureThy.thms_of: theory -> (string * thm) list
  2510   PureThy.all_thms_of: theory -> (string * thm) list
  2511 
  2512 * Pure: print_tac now outputs the goal through the trace channel.
  2513 
  2514 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2515 Reference Toplevel.debug (default false) controls detailed printing
  2516 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2517 controls execution profiling -- set to 1 for time and 2 for space
  2518 (both increase the runtime).
  2519 
  2520 * Isar session: The initial use of ROOT.ML is now always timed,
  2521 i.e. the log will show the actual process times, in contrast to the
  2522 elapsed wall-clock time that the outer shell wrapper produces.
  2523 
  2524 * Simplifier: improved handling of bound variables (nameless
  2525 representation, avoid allocating new strings).  Simprocs that invoke
  2526 the Simplifier recursively should use Simplifier.inherit_bounds to
  2527 avoid local name clashes.  Failure to do so produces warnings
  2528 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2529 for further details.
  2530 
  2531 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2532 bindings for all theorems stored within a given theory; this may help
  2533 in porting non-Isar theories to Isar ones, while keeping ML proof
  2534 scripts for the time being.
  2535 
  2536 * ML operator HTML.with_charset specifies the charset begin used for
  2537 generated HTML files.  For example:
  2538 
  2539   HTML.with_charset "utf-8" use_thy "Hebrew";
  2540   HTML.with_charset "utf-8" use_thy "Chinese";
  2541 
  2542 
  2543 *** System ***
  2544 
  2545 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2546 isabelle, isatool etc.).
  2547 
  2548 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2549 isatool doc, isatool mkdir, display_drafts etc.).
  2550 
  2551 * isatool usedir: option -f allows specification of the ML file to be
  2552 used by Isabelle; default is ROOT.ML.
  2553 
  2554 * New isatool version outputs the version identifier of the Isabelle
  2555 distribution being used.
  2556 
  2557 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2558 (containing Boolean satisfiability problems) into Isabelle/HOL
  2559 theories.
  2560 
  2561 
  2562 
  2563 New in Isabelle2004 (April 2004)
  2564 --------------------------------
  2565 
  2566 *** General ***
  2567 
  2568 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2569   Replaces linorder.ML.
  2570 
  2571 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2572   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2573   (\<a>...\<z>), are now considered normal letters, and can therefore
  2574   be used anywhere where an ASCII letter (a...zA...Z) has until
  2575   now. COMPATIBILITY: This obviously changes the parsing of some
  2576   terms, especially where a symbol has been used as a binder, say
  2577   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2578   as an identifier.  Fix it by inserting a space around former
  2579   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2580   existing theory and ML files.
  2581 
  2582 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2583 
  2584 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2585   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2586   a normal (but invisible) letter. For multiple letter subscripts repeat
  2587   \<^isub> like this: x\<^isub>1\<^isub>2.
  2588 
  2589 * Pure: There are now sub-/superscripts that can span more than one
  2590   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2591   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2592   superscript. The new control characters are not identifier parts.
  2593 
  2594 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2595   content of "..." to the latex file instead of \isacntrl... . The "..."
  2596   may consist of any printable characters excluding the end bracket >.
  2597 
  2598 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2599   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2600   declare constants "final", which prevents their being given a definition
  2601   later.  It is useful for constants whose behaviour is fixed axiomatically
  2602   rather than definitionally, such as the meta-logic connectives.
  2603 
  2604 * Pure: 'instance' now handles general arities with general sorts
  2605   (i.e. intersections of classes),
  2606 
  2607 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2608   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2609   It can be changed to alter the colors/layout of generated pages.
  2610 
  2611 
  2612 *** Isar ***
  2613 
  2614 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2615   cut_tac, subgoal_tac and thin_tac:
  2616   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2617     locales are no longer forced to write Isar proof scripts.
  2618     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2619     emulations.
  2620   - INCOMPATIBILITY: names of variables to be instantiated may no
  2621     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2622     This is consistent with the instantiation attribute "where".
  2623 
  2624 * Attributes "where" and "of":
  2625   - Now take type variables of instantiated theorem into account when reading
  2626     the instantiation string.  This fixes a bug that caused instantiated
  2627     theorems to have too special types in some circumstances.
  2628   - "where" permits explicit instantiations of type variables.
  2629 
  2630 * Calculation commands "moreover" and "also" no longer interfere with
  2631   current facts ("this"), admitting arbitrary combinations with "then"
  2632   and derived forms.
  2633 
  2634 * Locales:
  2635   - Goal statements involving the context element "includes" no longer
  2636     generate theorems with internal delta predicates (those ending on
  2637     "_axioms") in the premise.
  2638     Resolve particular premise with <locale>.intro to obtain old form.
  2639   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2640     specification and "includes" elements in goal statement.
  2641   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2642     [intro?] and [elim?] (respectively) by default.
  2643   - Experimental command for instantiation of locales in proof contexts:
  2644         instantiate <label>[<attrs>]: <loc>
  2645     Instantiates locale <loc> and adds all its theorems to the current context
  2646     taking into account their attributes.  Label and attrs are optional
  2647     modifiers, like in theorem declarations.  If present, names of
  2648     instantiated theorems are qualified with <label>, and the attributes
  2649     <attrs> are applied after any attributes these theorems might have already.
  2650       If the locale has assumptions, a chained fact of the form
  2651     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2652     are derived.  The command does not support old-style locales declared
  2653     with "locale (open)".
  2654       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2655 
  2656 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2657   (Isar) contexts.
  2658 
  2659 
  2660 *** HOL ***
  2661 
  2662 * Proof import: new image HOL4 contains the imported library from
  2663   the HOL4 system with about 2500 theorems. It is imported by
  2664   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2665   can be used like any other Isabelle image.  See
  2666   HOL/Import/HOL/README for more information.
  2667 
  2668 * Simplifier:
  2669   - Much improved handling of linear and partial orders.
  2670     Reasoners for linear and partial orders are set up for type classes
  2671     "linorder" and "order" respectively, and are added to the default simpset
  2672     as solvers.  This means that the simplifier can build transitivity chains
  2673     to solve goals from the assumptions.
  2674   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2675     of blast or auto after simplification become unnecessary because the goal
  2676     is solved by simplification already.
  2677 
  2678 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2679     all proved in axiomatic type classes for semirings, rings and fields.
  2680 
  2681 * Numerics:
  2682   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2683     now formalized using the Ring_and_Field theory mentioned above.
  2684   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2685     than before, because now they are set up once in a generic manner.
  2686   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2687     Look for the general versions in Ring_and_Field (and Power if they concern
  2688     exponentiation).
  2689 
  2690 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2691 
  2692 * Records:
  2693   - Record types are now by default printed with their type abbreviation
  2694     instead of the list of all field types. This can be configured via
  2695     the reference "print_record_type_abbr".
  2696   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2697     (not enabled by default).
  2698   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2699     EX x. x = sel r to True (not enabled by default).
  2700   - Tactic "record_split_simp_tac" to split and simplify records added.
  2701 
  2702 * 'specification' command added, allowing for definition by
  2703   specification.  There is also an 'ax_specification' command that
  2704   introduces the new constants axiomatically.
  2705 
  2706 * arith(_tac) is now able to generate counterexamples for reals as well.
  2707 
  2708 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2709 
  2710 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2711   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2712 
  2713 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2714   matrix theory to linear programming.
  2715 
  2716 * Unions and Intersections:
  2717   The latex output syntax of UN and INT has been changed
  2718   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2719   i.e. the index formulae has become a subscript.
  2720   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2721 
  2722 * Unions and Intersections over Intervals:
  2723   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2724   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2725   like in normal math, and corresponding versions for < and for intersection.
  2726 
  2727 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2728   lexicographic dictonary ordering has been added as "lexord".
  2729 
  2730 * ML: the legacy theory structures Int and List have been removed. They had
  2731   conflicted with ML Basis Library structures having the same names.
  2732 
  2733 * 'refute' command added to search for (finite) countermodels.  Only works
  2734   for a fragment of HOL.  The installation of an external SAT solver is
  2735   highly recommended.  See "HOL/Refute.thy" for details.
  2736 
  2737 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2738   formulae under an assignment of free variables to random values.
  2739   In contrast to 'refute', it can deal with inductive datatypes,
  2740   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2741   for examples.
  2742 
  2743 
  2744 *** HOLCF ***
  2745 
  2746 * Streams now come with concatenation and are part of the HOLCF image
  2747 
  2748 
  2749 
  2750 New in Isabelle2003 (May 2003)
  2751 ------------------------------
  2752 
  2753 *** General ***
  2754 
  2755 * Provers/simplifier:
  2756 
  2757   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2758     Assumptions are now subject to complete mutual simplification,
  2759     not just from left to right. The simplifier now preserves
  2760     the order of assumptions.
  2761 
  2762     Potential INCOMPATIBILITY:
  2763 
  2764     -- simp sometimes diverges where the old version did
  2765        not, e.g. invoking simp on the goal
  2766 
  2767         [| P (f x); y = x; f x = f y |] ==> Q
  2768 
  2769        now gives rise to the infinite reduction sequence
  2770 
  2771         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2772 
  2773        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2774        kind of problem.
  2775 
  2776     -- Tactics combining classical reasoner and simplification (such as auto)
  2777        are also affected by this change, because many of them rely on
  2778        simp. They may sometimes diverge as well or yield a different numbers
  2779        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2780        in case of problems. Sometimes subsequent calls to the classical
  2781        reasoner will fail because a preceeding call to the simplifier too
  2782        eagerly simplified the goal, e.g. deleted redundant premises.
  2783 
  2784   - The simplifier trace now shows the names of the applied rewrite rules
  2785 
  2786   - You can limit the number of recursive invocations of the simplifier
  2787     during conditional rewriting (where the simplifie tries to solve the
  2788     conditions before applying the rewrite rule):
  2789     ML "simp_depth_limit := n"
  2790     where n is an integer. Thus you can force termination where previously
  2791     the simplifier would diverge.
  2792 
  2793   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2794 
  2795   - No longer aborts on failed congruence proof.  Instead, the
  2796     congruence is ignored.
  2797 
  2798 * Pure: New generic framework for extracting programs from constructive
  2799   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2800   as HOL/Extraction for some case studies.
  2801 
  2802 * Pure: The main goal of the proof state is no longer shown by default, only
  2803 the subgoals. This behaviour is controlled by a new flag.
  2804    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2805 (ML: Proof.show_main_goal).
  2806 
  2807 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2808 rules whose conclusion matches subgoal 1:
  2809       PG menu: Isabelle/Isar -> Show me -> matching rules
  2810 The rules are ordered by how closely they match the subgoal.
  2811 In particular, rules that solve a subgoal outright are displayed first
  2812 (or rather last, the way they are printed).
  2813 (ML: ProofGeneral.print_intros())
  2814 
  2815 * Pure: New flag trace_unify_fail causes unification to print
  2816 diagnostic information (PG: in trace buffer) when it fails. This is
  2817 useful for figuring out why single step proofs like rule, erule or
  2818 assumption failed.
  2819 
  2820 * Pure: Locale specifications now produce predicate definitions
  2821 according to the body of text (covering assumptions modulo local
  2822 definitions); predicate "loc_axioms" covers newly introduced text,
  2823 while "loc" is cumulative wrt. all included locale expressions; the
  2824 latter view is presented only on export into the global theory
  2825 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2826 on the old view without predicates;
  2827 
  2828 * Pure: predefined locales "var" and "struct" are useful for sharing
  2829 parameters (as in CASL, for example); just specify something like
  2830 ``var x + var y + struct M'' as import;
  2831 
  2832 * Pure: improved thms_containing: proper indexing of facts instead of
  2833 raw theorems; check validity of results wrt. current name space;
  2834 include local facts of proof configuration (also covers active
  2835 locales), cover fixed variables in index; may use "_" in term
  2836 specification; an optional limit for the number of printed facts may
  2837 be given (the default is 40);
  2838 
  2839 * Pure: disallow duplicate fact bindings within new-style theory files
  2840 (batch-mode only);
  2841 
  2842 * Provers: improved induct method: assumptions introduced by case
  2843 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2844 the goal statement); "foo" still refers to all facts collectively;
  2845 
  2846 * Provers: the function blast.overloaded has been removed: all constants
  2847 are regarded as potentially overloaded, which improves robustness in exchange
  2848 for slight decrease in efficiency;
  2849 
  2850 * Provers/linorder: New generic prover for transitivity reasoning over
  2851 linear orders.  Note: this prover is not efficient!
  2852 
  2853 * Isar: preview of problems to finish 'show' now produce an error
  2854 rather than just a warning (in interactive mode);
  2855 
  2856 
  2857 *** HOL ***
  2858 
  2859 * arith(_tac)
  2860 
  2861  - Produces a counter example if it cannot prove a goal.
  2862    Note that the counter example may be spurious if the goal is not a formula
  2863    of quantifier-free linear arithmetic.
  2864    In ProofGeneral the counter example appears in the trace buffer.
  2865 
  2866  - Knows about div k and mod k where k is a numeral of type nat or int.
  2867 
  2868  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2869    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2870    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2871 
  2872 * simp's arithmetic capabilities have been enhanced a bit: it now
  2873 takes ~= in premises into account (by performing a case split);
  2874 
  2875 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2876 are distributed over a sum of terms;
  2877 
  2878 * New tactic "trans_tac" and method "trans" instantiate
  2879 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2880 "<=", "<" and "=").
  2881 
  2882 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2883 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2884 
  2885 * 'typedef' command has new option "open" to suppress the set
  2886 definition;
  2887 
  2888 * functions Min and Max on finite sets have been introduced (theory
  2889 Finite_Set);
  2890 
  2891 * attribute [symmetric] now works for relations as well; it turns
  2892 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2893 
  2894 * induct over a !!-quantified statement (say !!x1..xn):
  2895   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2896 
  2897 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2898 %x. None. Warning: empty_def now refers to the previously hidden definition
  2899 of the empty set.
  2900 
  2901 * Algebra: formalization of classical algebra.  Intended as base for
  2902 any algebraic development in Isabelle.  Currently covers group theory
  2903 (up to Sylow's theorem) and ring theory (Universal Property of
  2904 Univariate Polynomials).  Contributions welcome;
  2905 
  2906 * GroupTheory: deleted, since its material has been moved to Algebra;
  2907 
  2908 * Complex: new directory of the complex numbers with numeric constants,
  2909 nonstandard complex numbers, and some complex analysis, standard and
  2910 nonstandard (Jacques Fleuriot);
  2911 
  2912 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2913 
  2914 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2915 Fleuriot);
  2916 
  2917 * Real/HahnBanach: updated and adapted to locales;
  2918 
  2919 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2920 Gray and Kramer);
  2921 
  2922 * UNITY: added the Meier-Sanders theory of progress sets;
  2923 
  2924 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2925 as abstract algorithms, instantiated to the JVM;
  2926 
  2927 * Bali: Java source language formalization. Type system, operational
  2928 semantics, axiomatic semantics. Supported language features:
  2929 classes, interfaces, objects,virtual methods, static methods,
  2930 static/instance fields, arrays, access modifiers, definite
  2931 assignment, exceptions.
  2932 
  2933 
  2934 *** ZF ***
  2935 
  2936 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2937 universe, etc.);
  2938 
  2939 * Main ZF: virtually all theories converted to new-style format;
  2940 
  2941 
  2942 *** ML ***
  2943 
  2944 * Pure: Tactic.prove provides sane interface for internal proofs;
  2945 omits the infamous "standard" operation, so this is more appropriate
  2946 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2947 
  2948 * Pure: improved error reporting of simprocs;
  2949 
  2950 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2951 up simprocs;
  2952 
  2953 
  2954 *** Document preparation ***
  2955 
  2956 * uses \par instead of \\ for line breaks in theory text. This may
  2957 shift some page breaks in large documents. To get the old behaviour
  2958 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2959 
  2960 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2961 other packages
  2962 
  2963 * \<euro> now needs package babel/greek instead of marvosym (which
  2964 broke \Rightarrow)
  2965 
  2966 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2967 textcomp package)
  2968 
  2969 
  2970 
  2971 New in Isabelle2002 (March 2002)
  2972 --------------------------------
  2973 
  2974 *** Document preparation ***
  2975 
  2976 * greatly simplified document preparation setup, including more
  2977 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2978 instructive isatool mkdir; users should basically be able to get
  2979 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2980 users may run a separate document processing stage manually like this:
  2981 "isatool usedir -D output HOL Test && isatool document Test/output";
  2982 
  2983 * theory dependency graph may now be incorporated into documents;
  2984 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2985 with \includegraphics of LaTeX;
  2986 
  2987 * proper spacing of consecutive markup elements, especially text
  2988 blocks after section headings;
  2989 
  2990 * support bold style (for single symbols only), input syntax is like
  2991 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2992 
  2993 * \<bullet> is now output as bold \cdot by default, which looks much
  2994 better in printed text;
  2995 
  2996 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2997 note that these symbols are currently unavailable in Proof General /
  2998 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2999 
  3000 * isatool latex no longer depends on changed TEXINPUTS, instead
  3001 isatool document copies the Isabelle style files to the target
  3002 location;
  3003 
  3004 
  3005 *** Isar ***
  3006 
  3007 * Pure/Provers: improved proof by cases and induction;
  3008   - 'case' command admits impromptu naming of parameters (such as
  3009     "case (Suc n)");
  3010   - 'induct' method divinates rule instantiation from the inductive
  3011     claim; no longer requires excessive ?P bindings for proper
  3012     instantiation of cases;
  3013   - 'induct' method properly enumerates all possibilities of set/type
  3014     rules; as a consequence facts may be also passed through *type*
  3015     rules without further ado;
  3016   - 'induct' method now derives symbolic cases from the *rulified*
  3017     rule (before it used to rulify cases stemming from the internal
  3018     atomized version); this means that the context of a non-atomic
  3019     statement becomes is included in the hypothesis, avoiding the
  3020     slightly cumbersome show "PROP ?case" form;
  3021   - 'induct' may now use elim-style induction rules without chaining
  3022     facts, using ``missing'' premises from the goal state; this allows
  3023     rules stemming from inductive sets to be applied in unstructured
  3024     scripts, while still benefitting from proper handling of non-atomic
  3025     statements; NB: major inductive premises need to be put first, all
  3026     the rest of the goal is passed through the induction;
  3027   - 'induct' proper support for mutual induction involving non-atomic
  3028     rule statements (uses the new concept of simultaneous goals, see
  3029     below);
  3030   - append all possible rule selections, but only use the first
  3031     success (no backtracking);
  3032   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3033   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3034   - added 'print_induct_rules' (covered by help item in recent Proof
  3035     General versions);
  3036   - moved induct/cases attributes to Pure, methods to Provers;
  3037   - generic method setup instantiated for FOL and HOL;
  3038 
  3039 * Pure: support multiple simultaneous goal statements, for example
  3040 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3041 meta-level mechanism, this acts as if several individual goals had
  3042 been stated separately; in particular common proof methods need to be
  3043 repeated in order to cover all claims; note that a single elimination
  3044 step is *not* sufficient to establish the two conjunctions, so this
  3045 fails:
  3046 
  3047   assume "A & B" then have A and B ..   (*".." fails*)
  3048 
  3049 better use "obtain" in situations as above; alternative refer to
  3050 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3051 
  3052 * Pure: proper integration with ``locales''; unlike the original
  3053 version by Florian Kammller, Isar locales package high-level proof
  3054 contexts rather than raw logical ones (e.g. we admit to include
  3055 attributes everywhere); operations on locales include merge and
  3056 rename; support for implicit arguments (``structures''); simultaneous
  3057 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3058 some examples;
  3059 
  3060 * Pure: the following commands have been ``localized'', supporting a
  3061 target locale specification "(in name)": 'lemma', 'theorem',
  3062 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3063 stored both within the locale and at the theory level (exported and
  3064 qualified by the locale name);
  3065 
  3066 * Pure: theory goals may now be specified in ``long'' form, with
  3067 ad-hoc contexts consisting of arbitrary locale elements. for example
  3068 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3069 definitions may be given, too); the result is a meta-level rule with
  3070 the context elements being discharged in the obvious way;
  3071 
  3072 * Pure: new proof command 'using' allows to augment currently used
  3073 facts after a goal statement ('using' is syntactically analogous to
  3074 'apply', but acts on the goal's facts only); this allows chained facts
  3075 to be separated into parts given before and after a claim, as in
  3076 ``from a and b have C using d and e <proof>'';
  3077 
  3078 * Pure: renamed "antecedent" case to "rule_context";
  3079 
  3080 * Pure: new 'judgment' command records explicit information about the
  3081 object-logic embedding (used by several tools internally); no longer
  3082 use hard-wired "Trueprop";
  3083 
  3084 * Pure: added 'corollary' command;
  3085 
  3086 * Pure: fixed 'token_translation' command;
  3087 
  3088 * Pure: removed obsolete 'exported' attribute;
  3089 
  3090 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3091 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3092 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3093 
  3094 * Pure: method 'atomize' presents local goal premises as object-level
  3095 statements (atomic meta-level propositions); setup controlled via
  3096 rewrite rules declarations of 'atomize' attribute; example
  3097 application: 'induct' method with proper rule statements in improper
  3098 proof *scripts*;
  3099 
  3100 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3101 now consider the syntactic context of assumptions, giving a better
  3102 chance to get type-inference of the arguments right (this is
  3103 especially important for locales);
  3104 
  3105 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3106 mode;
  3107 
  3108 * Pure/obtain: the formal conclusion "thesis", being marked as
  3109 ``internal'', may no longer be reference directly in the text;
  3110 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3111 situations;
  3112 
  3113 * Pure: generic 'sym' attribute which declares a rule both as pure
  3114 'elim?' and for the 'symmetric' operation;
  3115 
  3116 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3117 text; the fixed correlation with particular command syntax has been
  3118 discontinued;
  3119 
  3120 * Pure: new method 'rules' is particularly well-suited for proof
  3121 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3122 but often produces more compact proof terms with less detours;
  3123 
  3124 * Pure/Provers/classical: simplified integration with pure rule
  3125 attributes and methods; the classical "intro?/elim?/dest?"
  3126 declarations coincide with the pure ones; the "rule" method no longer
  3127 includes classically swapped intros; "intro" and "elim" methods no
  3128 longer pick rules from the context; also got rid of ML declarations
  3129 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3130 INCOMPATIBILITY;
  3131 
  3132 * Provers/classical: attribute 'swapped' produces classical inversions
  3133 of introduction rules;
  3134 
  3135 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3136 rules instead of full simplifier context; 'iff' attribute handles
  3137 conditional rules;
  3138 
  3139 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3140 
  3141 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3142 "(permissive)" option to recover old behavior;
  3143 
  3144 * HOL: 'inductive' no longer features separate (collective) attributes
  3145 for 'intros' (was found too confusing);
  3146 
  3147 * HOL: properly declared induction rules less_induct and
  3148 wf_induct_rule;
  3149 
  3150 
  3151 *** HOL ***
  3152 
  3153 * HOL: moved over to sane numeral syntax; the new policy is as
  3154 follows:
  3155 
  3156   - 0 and 1 are polymorphic constants, which are defined on any
  3157   numeric type (nat, int, real etc.);
  3158 
  3159   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3160   binary representation internally;
  3161 
  3162   - type nat has special constructor Suc, and generally prefers Suc 0
  3163   over 1::nat and Suc (Suc 0) over 2::nat;
  3164 
  3165 This change may cause significant problems of INCOMPATIBILITY; here
  3166 are some hints on converting existing sources:
  3167 
  3168   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3169   entities, so expressions involving "-" (unary or binary minus) need
  3170   to be spaced properly;
  3171 
  3172   - existing occurrences of "1" may need to be constraint "1::nat" or
  3173   even replaced by Suc 0; similar for old "2";
  3174 
  3175   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3176 
  3177   - remove all special provisions on numerals in proofs;
  3178 
  3179 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3180 representation (depends on bin_arith_simps in the default context);
  3181 
  3182 * HOL: symbolic syntax for x^2 (numeral 2);
  3183 
  3184 * HOL: the class of all HOL types is now called "type" rather than
  3185 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3186 in axclass/classes, instance/arities, and (usually rare) occurrences
  3187 in typings (of consts etc.); internally the class is called
  3188 "HOL.type", ML programs should refer to HOLogic.typeS;
  3189 
  3190 * HOL/record package improvements:
  3191   - new derived operations "fields" to build a partial record section,
  3192     "extend" to promote a fixed record to a record scheme, and
  3193     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3194     declared as simp by default;
  3195   - shared operations ("more", "fields", etc.) now need to be always
  3196     qualified) --- potential INCOMPATIBILITY;
  3197   - removed "make_scheme" operations (use "make" with "extend") --
  3198     INCOMPATIBILITY;
  3199   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3200   - provides cases/induct rules for use with corresponding Isar
  3201     methods (for concrete records, record schemes, concrete more
  3202     parts, and schematic more parts -- in that order);
  3203   - internal definitions directly based on a light-weight abstract
  3204     theory of product types over typedef rather than datatype;
  3205 
  3206 * HOL: generic code generator for generating executable ML code from
  3207 specifications; specific support for HOL constructs such as inductive
  3208 datatypes and sets, as well as recursive functions; can be invoked
  3209 via 'generate_code' theory section;
  3210 
  3211 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3212 
  3213 * HOL: consolidated and renamed several theories.  In particular:
  3214         Ord.thy has been absorbed into HOL.thy
  3215         String.thy has been absorbed into List.thy
  3216 
  3217 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3218 (beware of argument permutation!);
  3219 
  3220 * HOL: linorder_less_split superseded by linorder_cases;
  3221 
  3222 * HOL/List: "nodups" renamed to "distinct";
  3223 
  3224 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3225 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3226   - Ex_def has changed, now need to use some_eq_ex
  3227 
  3228 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3229 in this (rare) case use:
  3230 
  3231   delSWrapper "split_all_tac"
  3232   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3233 
  3234 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3235 MAY FAIL;
  3236 
  3237 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3238 Isabelle's type classes, ^ on functions and relations has too general
  3239 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3240 necessary to attach explicit type constraints;
  3241 
  3242 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3243 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3244 renamed accordingly (eg "compI" -> "rel_compI").
  3245 
  3246 * HOL: syntax translations now work properly with numerals and records
  3247 expressions;
  3248 
  3249 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3250 of "lam" -- INCOMPATIBILITY;
  3251 
  3252 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3253 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3254 renamed "Product_Type.unit";
  3255 
  3256 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3257 
  3258 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3259 the "cases" method);
  3260 
  3261 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3262 Florian Kammller);
  3263 
  3264 * HOL/IMP: updated and converted to new-style theory format; several
  3265 parts turned into readable document, with proper Isar proof texts and
  3266 some explanations (by Gerwin Klein);
  3267 
  3268 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3269 
  3270 * HOL-Hyperreal is now a logic image;
  3271 
  3272 
  3273 *** HOLCF ***
  3274 
  3275 * Isar: consts/constdefs supports mixfix syntax for continuous
  3276 operations;
  3277 
  3278 * Isar: domain package adapted to new-style theory format, e.g. see
  3279 HOLCF/ex/Dnat.thy;
  3280 
  3281 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3282 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3283 lift.induct_tac, always use UU instead of Undef;
  3284 
  3285 * HOLCF/IMP: updated and converted to new-style theory;
  3286 
  3287 
  3288 *** ZF ***
  3289 
  3290 * Isar: proper integration of logic-specific tools and packages,
  3291 including theory commands '(co)inductive', '(co)datatype',
  3292 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3293 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3294 
  3295 * theory Main no longer includes AC; for the Axiom of Choice, base
  3296 your theory on Main_ZFC;
  3297 
  3298 * the integer library now covers quotients and remainders, with many
  3299 laws relating division to addition, multiplication, etc.;
  3300 
  3301 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3302 typeless version of the formalism;
  3303 
  3304 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3305 format;
  3306 
  3307 * ZF/Induct: new directory for examples of inductive definitions,
  3308 including theory Multiset for multiset orderings; converted to
  3309 new-style theory format;
  3310 
  3311 * ZF: many new theorems about lists, ordinals, etc.;
  3312 
  3313 
  3314 *** General ***
  3315 
  3316 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3317 variable proof controls level of detail: 0 = no proofs (only oracle
  3318 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3319 also ref manual for further ML interfaces;
  3320 
  3321 * Pure/axclass: removed obsolete ML interface
  3322 goal_subclass/goal_arity;
  3323 
  3324 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3325 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3326 separate tokens, so expressions involving minus need to be spaced
  3327 properly;
  3328 
  3329 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3330 rather than "infixl" or "infixr";
  3331 
  3332 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3333 sort constraint specifications in type inference; e.g. "x::_::foo"
  3334 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3335 type variable);
  3336 
  3337 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3338 control output of nested => (types); the default behavior is
  3339 "type_brackets";
  3340 
  3341 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3342 tokens into AST constants;
  3343 
  3344 * Pure/syntax: prefer later declarations of translations and print
  3345 translation functions; potential INCOMPATIBILITY: need to reverse
  3346 multiple declarations for same syntax element constant;
  3347 
  3348 * Pure/show_hyps reset by default (in accordance to existing Isar
  3349 practice);
  3350 
  3351 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3352 addSafter;
  3353 
  3354 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3355 as well;
  3356 
  3357 * system: tested support for MacOS X; should be able to get Isabelle +
  3358 Proof General to work in a plain Terminal after installing Poly/ML
  3359 (e.g. from the Isabelle distribution area) and GNU bash alone
  3360 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3361 support requires further installations, e.g. from
  3362 http://fink.sourceforge.net/);
  3363 
  3364 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3365 
  3366 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3367 of 40 MB), cf. ML_OPTIONS;
  3368 
  3369 * system: Proof General keywords specification is now part of the
  3370 Isabelle distribution (see etc/isar-keywords.el);
  3371 
  3372 * system: support for persistent Proof General sessions (refrain from
  3373 outdating all loaded theories on startup); user may create writable
  3374 logic images like this: ``isabelle -q HOL Test'';
  3375 
  3376 * system: smart selection of Isabelle process versus Isabelle
  3377 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3378 run both "isabelle" and "Isabelle" even if file names are badly
  3379 damaged (executable inspects the case of the first letter of its own
  3380 name); added separate "isabelle-process" and "isabelle-interface";
  3381 
  3382 * system: refrain from any attempt at filtering input streams; no
  3383 longer support ``8bit'' encoding of old isabelle font, instead proper
  3384 iso-latin characters may now be used; the related isatools
  3385 "symbolinput" and "nonascii" have disappeared as well;
  3386 
  3387 * system: removed old "xterm" interface (the print modes "xterm" and
  3388 "xterm_color" are still available for direct use in a suitable
  3389 terminal);
  3390 
  3391 
  3392 
  3393 New in Isabelle99-2 (February 2001)
  3394 -----------------------------------
  3395 
  3396 *** Overview of INCOMPATIBILITIES ***
  3397 
  3398 * HOL: please note that theories in the Library and elsewhere often use the
  3399 new-style (Isar) format; to refer to their theorems in an ML script you must
  3400 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3401 
  3402 * HOL: inductive package no longer splits induction rule aggressively,
  3403 but only as far as specified by the introductions given; the old
  3404 format may be recovered via ML function complete_split_rule or attribute
  3405 'split_rule (complete)';
  3406 
  3407 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3408 gfp_Tarski to gfp_unfold;
  3409 
  3410 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3411 
  3412 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3413 relation); infix "^^" has been renamed "``"; infix "``" has been
  3414 renamed "`"; "univalent" has been renamed "single_valued";
  3415 
  3416 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3417 operation;
  3418 
  3419 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3420 
  3421 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3422 
  3423 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3424 consequence, it is no longer monotonic wrt. the local goal context
  3425 (which is now passed through the inductive cases);
  3426 
  3427 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3428 \<gg> to \<ggreater>;
  3429 
  3430 
  3431 *** Document preparation ***
  3432 
  3433 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3434 available: are "it" for near math-mode best-style output, "sl" for
  3435 slanted text style, and "tt" for plain type-writer; if no
  3436 \isabellestyle command is given, output is according to slanted
  3437 type-writer);
  3438 
  3439 * support sub/super scripts (for single symbols only), input syntax is
  3440 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3441 
  3442 * some more standard symbols; see Appendix A of the system manual for
  3443 the complete list of symbols defined in isabellesym.sty;
  3444 
  3445 * improved isabelle style files; more abstract symbol implementation
  3446 (should now use \isamath{...} and \isatext{...} in custom symbol
  3447 definitions);
  3448 
  3449 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3450 state; Note that presentation of goal states does not conform to
  3451 actual human-readable proof documents.  Please do not include goal
  3452 states into document output unless you really know what you are doing!
  3453 
  3454 * proper indentation of antiquoted output with proportional LaTeX
  3455 fonts;
  3456 
  3457 * no_document ML operator temporarily disables LaTeX document
  3458 generation;
  3459 
  3460 * isatool unsymbolize tunes sources for plain ASCII communication;
  3461 
  3462 
  3463 *** Isar ***
  3464 
  3465 * Pure: Isar now suffers initial goal statements to contain unbound
  3466 schematic variables (this does not conform to actual readable proof
  3467 documents, due to unpredictable outcome and non-compositional proof
  3468 checking); users who know what they are doing may use schematic goals
  3469 for Prolog-style synthesis of proven results;
  3470 
  3471 * Pure: assumption method (an implicit finishing) now handles actual
  3472 rules as well;
  3473 
  3474 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3475 initial goal, declare "that" only as Pure intro (only for single
  3476 steps); the "that" rule assumption may now be involved in implicit
  3477 finishing, thus ".." becomes a feasible for trivial obtains;
  3478 
  3479 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3480 instance proofs may be performed by "..";
  3481 
  3482 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3483 statements as well;
  3484 
  3485 * Pure: more robust selection of calculational rules;
  3486 
  3487 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3488 rule (as well as the assumption rule);
  3489 
  3490 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3491 lemmas, using the graph browser tool;
  3492 
  3493 * Pure: predict failure of "show" in interactive mode;
  3494 
  3495 * Pure: 'thms_containing' now takes actual terms as arguments;
  3496 
  3497 * HOL: improved method 'induct' --- now handles non-atomic goals
  3498 (potential INCOMPATIBILITY); tuned error handling;
  3499 
  3500 * HOL: cases and induct rules now provide explicit hints about the
  3501 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3502 any remaining facts are inserted into the goal verbatim;
  3503 
  3504 * HOL: local contexts (aka cases) may now contain term bindings as
  3505 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3506 the result to be shown in each case;
  3507 
  3508 * HOL: added 'recdef_tc' command;
  3509 
  3510 * isatool convert assists in eliminating legacy ML scripts;
  3511 
  3512 
  3513 *** HOL ***
  3514 
  3515 * HOL/Library: a collection of generic theories to be used together
  3516 with main HOL; the theory loader path already includes this directory
  3517 by default; the following existing theories have been moved here:
  3518 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3519 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3520 
  3521 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3522 modelling and verification task performed in Isabelle/HOL +
  3523 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3524 
  3525 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3526 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3527 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3528 'domain', this makes the theory consistent with mathematical
  3529 literature;
  3530 
  3531 * HOL basics: added overloaded operations "inverse" and "divide"
  3532 (infix "/"), syntax for generic "abs" operation, generic summation
  3533 operator \<Sum>;
  3534 
  3535 * HOL/typedef: simplified package, provide more useful rules (see also
  3536 HOL/subset.thy);
  3537 
  3538 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3539 now expressed as a proper nested rule (old-style tactic scripts may
  3540 require atomize_strip_tac to cope with non-atomic premises);
  3541 
  3542 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3543 to "split_conv" (old name still available for compatibility);
  3544 
  3545 * HOL: improved concrete syntax for strings (e.g. allows translation
  3546 rules with string literals);
  3547 
  3548 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3549  and Fleuriot's mechanization of analysis, including the transcendental
  3550  functions for the reals;
  3551 
  3552 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3553 
  3554 
  3555 *** CTT ***
  3556 
  3557 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3558 "lam" is displayed as TWO lambda-symbols
  3559 
  3560 * CTT: theory Main now available, containing everything (that is, Bool
  3561 and Arith);
  3562 
  3563 
  3564 *** General ***
  3565 
  3566 * Pure: the Simplifier has been implemented properly as a derived rule
  3567 outside of the actual kernel (at last!); the overall performance
  3568 penalty in practical applications is about 50%, while reliability of
  3569 the Isabelle inference kernel has been greatly improved;
  3570 
  3571 * print modes "brackets" and "no_brackets" control output of nested =>
  3572 (types) and ==> (props); the default behaviour is "brackets";
  3573 
  3574 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3575 as assumptions as well;
  3576 
  3577 * system: support Poly/ML 4.0;
  3578 
  3579 * system: isatool install handles KDE version 1 or 2;
  3580 
  3581 
  3582 
  3583 New in Isabelle99-1 (October 2000)
  3584 ----------------------------------
  3585 
  3586 *** Overview of INCOMPATIBILITIES ***
  3587 
  3588 * HOL: simplification of natural numbers is much changed; to partly
  3589 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3590 issue the following ML commands:
  3591 
  3592   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3593   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3594 
  3595 * HOL: simplification no longer dives into case-expressions; this is
  3596 controlled by "t.weak_case_cong" for each datatype t;
  3597 
  3598 * HOL: nat_less_induct renamed to less_induct;
  3599 
  3600 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3601 fixsome to patch .thy and .ML sources automatically;
  3602 
  3603   select_equality  -> some_equality
  3604   select_eq_Ex     -> some_eq_ex
  3605   selectI2EX       -> someI2_ex
  3606   selectI2         -> someI2
  3607   selectI          -> someI
  3608   select1_equality -> some1_equality
  3609   Eps_sym_eq       -> some_sym_eq_trivial
  3610   Eps_eq           -> some_eq_trivial
  3611 
  3612 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3613 
  3614 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3615 instead);
  3616 
  3617 * HOL: the recursion equations generated by 'recdef' are now called
  3618 f.simps instead of f.rules;
  3619 
  3620 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3621 
  3622 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3623 sometimes be needed;
  3624 
  3625 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3626 
  3627 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3628 
  3629 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3630 product is now "<*>" instead of "Times"; the lexicographic product is
  3631 now "<*lex*>" instead of "**";
  3632 
  3633 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3634 of main HOL, but was unused); better use HOL's datatype package;
  3635 
  3636 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3637 the old syntax may be recovered as follows:
  3638 
  3639   syntax (symbols)
  3640     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3641       (infixl "\\<oplus>" 100)
  3642 
  3643 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3644 
  3645 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3646 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3647 internally;
  3648 
  3649 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3650 changed from A/r to A//r;
  3651 
  3652 * ZF: new treatment of arithmetic (nat & int) may break some old
  3653 proofs;
  3654 
  3655 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3656 rulify -> rule_format, elimify -> elim_format, ...);
  3657 
  3658 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3659 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3660 should have to change intro!! to intro? only); replaced "delrule" by
  3661 "rule del";
  3662 
  3663 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3664 
  3665 * Provers: strengthened force_tac by using new first_best_tac;
  3666 
  3667 * LaTeX document preparation: several changes of isabelle.sty (see
  3668 lib/texinputs);
  3669 
  3670 
  3671 *** Document preparation ***
  3672 
  3673 * formal comments (text blocks etc.) in new-style theories may now
  3674 contain antiquotations of thm/prop/term/typ/text to be presented
  3675 according to latex print mode; concrete syntax is like this:
  3676 @{term[show_types] "f(x) = a + x"};
  3677 
  3678 * isatool mkdir provides easy setup of Isabelle session directories,
  3679 including proper document sources;
  3680 
  3681 * generated LaTeX sources are now deleted after successful run
  3682 (isatool document -c); may retain a copy somewhere else via -D option
  3683 of isatool usedir;
  3684 
  3685 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3686 style files, achieving self-contained LaTeX sources and simplifying
  3687 LaTeX debugging;
  3688 
  3689 * old-style theories now produce (crude) LaTeX output as well;
  3690 
  3691 * browser info session directories are now self-contained (may be put
  3692 on WWW server seperately); improved graphs of nested sessions; removed
  3693 graph for 'all sessions';
  3694 
  3695 * several improvements in isabelle style files; \isabellestyle{it}
  3696 produces fake math mode output; \isamarkupheader is now \section by
  3697 default; see lib/texinputs/isabelle.sty etc.;
  3698 
  3699 
  3700 *** Isar ***
  3701 
  3702 * Isar/Pure: local results and corresponding term bindings are now
  3703 subject to Hindley-Milner polymorphism (similar to ML); this
  3704 accommodates incremental type-inference very nicely;
  3705 
  3706 * Isar/Pure: new derived language element 'obtain' supports
  3707 generalized existence reasoning;
  3708 
  3709 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3710 support accumulation of results, without applying any rules yet;
  3711 useful to collect intermediate results without explicit name
  3712 references, and for use with transitivity rules with more than 2
  3713 premises;
  3714 
  3715 * Isar/Pure: scalable support for case-analysis type proofs: new
  3716 'case' language element refers to local contexts symbolically, as
  3717 produced by certain proof methods; internally, case names are attached
  3718 to theorems as "tags";
  3719 
  3720 * Isar/Pure: theory command 'hide' removes declarations from
  3721 class/type/const name spaces;
  3722 
  3723 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3724 indicate potential overloading;
  3725 
  3726 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3727 
  3728 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3729 "{a,b,c}" instead of {a,b,c};
  3730 
  3731 * Isar/Pure now provides its own version of intro/elim/dest
  3732 attributes; useful for building new logics, but beware of confusion
  3733 with the version in Provers/classical;
  3734 
  3735 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3736 case name 'antecedent';
  3737 
  3738 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3739 to the current context is now done automatically);
  3740 
  3741 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3742 for definining proof methods in ML;
  3743 
  3744 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3745 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3746 most cases, one should have to change intro!! to intro? only);
  3747 replaced "delrule" by "rule del";
  3748 
  3749 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3750 'symmetric' attribute (the latter supercedes [RS sym]);
  3751 
  3752 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3753 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3754 well (including splits);
  3755 
  3756 * Isar/Provers: Simplifier and Classical methods now support all kind
  3757 of modifiers used in the past, including 'cong', 'iff', etc.
  3758 
  3759 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3760 of Simplifier and Classical reasoner);
  3761 
  3762 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3763 now support named cases; major packages (inductive, datatype, primrec,
  3764 recdef) support case names and properly name parameters;
  3765 
  3766 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3767 monotonicity conditions are extracted to be proven at end of
  3768 calculations;
  3769 
  3770 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3771 method anyway;
  3772 
  3773 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3774 split_if split_if_asm; datatype package provides theorems foo.splits =
  3775 foo.split foo.split_asm for each datatype;
  3776 
  3777 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3778 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3779 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3780 use "(cases (simplified))" method in proper proof texts);
  3781 
  3782 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3783 
  3784 * Isar: names of theorems etc. may be natural numbers as well;
  3785 
  3786 * Isar: 'pr' command: optional arguments for goals_limit and
  3787 ProofContext.prems_limit; no longer prints theory contexts, but only
  3788 proof states;
  3789 
  3790 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3791 additional print modes to be specified; e.g. "pr(latex)" will print
  3792 proof state according to the Isabelle LaTeX style;
  3793 
  3794 * Isar: improved support for emulating tactic scripts, including proof
  3795 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3796 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3797 (for HOL datatypes);
  3798 
  3799 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3800 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3801 'proof method scripts' have to be in depth-first order;
  3802 
  3803 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3804 
  3805 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3806 should instead use individual commands for printing items
  3807 (print_commands, print_methods etc.);
  3808 
  3809 * Isar: added 'nothing' --- the empty list of theorems;
  3810 
  3811 
  3812 *** HOL ***
  3813 
  3814 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3815 corresponding virtual machine and a specification of its bytecode
  3816 verifier and a lightweight bytecode verifier, including proofs of
  3817 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3818 Cornelia Pusch (see also the homepage of project Bali at
  3819 http://isabelle.in.tum.de/Bali/);
  3820 
  3821 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3822 Clemens Ballarin;
  3823 
  3824 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3825 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3826 Rasmussen;
  3827 
  3828 * HOL/Lattice: fundamental concepts of lattice theory and order
  3829 structures, including duals, properties of bounds versus algebraic
  3830 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3831 Theorem for complete lattices etc.; may also serve as a demonstration
  3832 for abstract algebraic reasoning using axiomatic type classes, and
  3833 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3834 
  3835 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3836 von Oheimb;
  3837 
  3838 * HOL/IMPP: extension of IMP with local variables and mutually
  3839 recursive procedures, by David von Oheimb;
  3840 
  3841 * HOL/Lambda: converted into new-style theory and document;
  3842 
  3843 * HOL/ex/Multiquote: example of multiple nested quotations and
  3844 anti-quotations -- basically a generalized version of de-Bruijn
  3845 representation; very useful in avoiding lifting of operations;
  3846 
  3847 * HOL/record: added general record equality rule to simpset; fixed
  3848 select-update simplification procedure to handle extended records as
  3849 well; admit "r" as field name;
  3850 
  3851 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3852 other numeric types and also as the identity of groups, rings, etc.;
  3853 
  3854 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3855 Types nat and int belong to this axclass;
  3856 
  3857 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3858    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3859    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3860   two terms #m*u and #n*u are replaced by #(m+n)*u
  3861     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3862   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3863     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3864 
  3865 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3866 powerful prover for predicate logic but knows nothing of clasets; see
  3867 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3868 
  3869 * HOL: new version of "case_tac" subsumes both boolean case split and
  3870 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3871 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3872 
  3873 * HOL: simplification no longer dives into case-expressions: only the
  3874 selector expression is simplified, but not the remaining arms; to
  3875 enable full simplification of case-expressions for datatype t, you may
  3876 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3877 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3878 
  3879 * HOL/recdef: the recursion equations generated by 'recdef' for
  3880 function 'f' are now called f.simps instead of f.rules; if all
  3881 termination conditions are proved automatically, these simplification
  3882 rules are added to the simpset, as in primrec; rules may be named
  3883 individually as well, resulting in a separate list of theorems for
  3884 each equation;
  3885 
  3886 * HOL/While is a new theory that provides a while-combinator. It
  3887 permits the definition of tail-recursive functions without the
  3888 provision of a termination measure. The latter is necessary once the
  3889 invariant proof rule for while is applied.
  3890 
  3891 * HOL: new (overloaded) notation for the set of elements below/above
  3892 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3893 
  3894 * HOL: theorems impI, allI, ballI bound as "strip";
  3895 
  3896 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3897 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3898 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3899 
  3900 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3901 
  3902 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3903 main HOL, but was unused);
  3904 
  3905 * HOL: fewer consts declared as global (e.g. have to refer to
  3906 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3907 
  3908 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3909 in case of overlap with user translations (e.g. judgements over
  3910 tuples); (note that the underlying logical represenation is still
  3911 bogus);
  3912 
  3913 
  3914 *** ZF ***
  3915 
  3916 * ZF: simplification automatically cancels common terms in arithmetic
  3917 expressions over nat and int;
  3918 
  3919 * ZF: new treatment of nat to minimize type-checking: all operators
  3920 coerce their operands to a natural number using the function natify,
  3921 making the algebraic laws unconditional;
  3922 
  3923 * ZF: as above, for int: operators coerce their operands to an integer
  3924 using the function intify;
  3925 
  3926 * ZF: the integer library now contains many of the usual laws for the
  3927 orderings, including $<=, and monotonicity laws for $+ and $*;
  3928 
  3929 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3930 simplification;
  3931 
  3932 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3933 to the simplifier and classical reasoner simultaneously;
  3934 
  3935 
  3936 *** General ***
  3937 
  3938 * Provers: blast_tac now handles actual object-logic rules as
  3939 assumptions; note that auto_tac uses blast_tac internally as well;
  3940 
  3941 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3942 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3943 
  3944 * Provers: delrules now handles destruct rules as well (no longer need
  3945 explicit make_elim);
  3946 
  3947 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3948   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3949 use instead the strong form,
  3950   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3951 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3952 from destruct-rules;
  3953 
  3954 * Provers: Simplifier.easy_setup provides a fast path to basic
  3955 Simplifier setup for new object-logics;
  3956 
  3957 * Pure: AST translation rules no longer require constant head on LHS;
  3958 
  3959 * Pure: improved name spaces: ambiguous output is qualified; support
  3960 for hiding of names;
  3961 
  3962 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3963 XSYMBOL_HOME; no longer need to do manual configuration in most
  3964 situations;
  3965 
  3966 * system: compression of ML heaps images may now be controlled via -c
  3967 option of isabelle and isatool usedir (currently only observed by
  3968 Poly/ML);
  3969 
  3970 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3971 useful for remote X11);
  3972 
  3973 * system: provide TAGS file for Isabelle sources;
  3974 
  3975 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3976 order;
  3977 
  3978 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3979 timing flag supersedes proof_timing and Toplevel.trace;
  3980 
  3981 * ML: new combinators |>> and |>>> for incremental transformations
  3982 with secondary results (e.g. certain theory extensions):
  3983 
  3984 * ML: PureThy.add_defs gets additional argument to indicate potential
  3985 overloading (usually false);
  3986 
  3987 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3988 results;
  3989 
  3990 
  3991 
  3992 New in Isabelle99 (October 1999)
  3993 --------------------------------
  3994 
  3995 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3996 
  3997 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3998 are no longer simplified.  (This allows the simplifier to unfold recursive
  3999 functional programs.)  To restore the old behaviour, declare
  4000 
  4001     Delcongs [if_weak_cong];
  4002 
  4003 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4004 complement;
  4005 
  4006 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4007 
  4008 * HOL/datatype: mutual_induct_tac no longer exists --
  4009   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4010 
  4011 * HOL/typedef: fixed type inference for representing set; type
  4012 arguments now have to occur explicitly on the rhs as type constraints;
  4013 
  4014 * ZF: The con_defs part of an inductive definition may no longer refer
  4015 to constants declared in the same theory;
  4016 
  4017 * HOL, ZF: the function mk_cases, generated by the inductive
  4018 definition package, has lost an argument.  To simplify its result, it
  4019 uses the default simpset instead of a supplied list of theorems.
  4020 
  4021 * HOL/List: the constructors of type list are now Nil and Cons;
  4022 
  4023 * Simplifier: the type of the infix ML functions
  4024         setSSolver addSSolver setSolver addSolver
  4025 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4026 for packaging solvers. A solver is created via
  4027         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4028 where the string argument is only a comment.
  4029 
  4030 
  4031 *** Proof tools ***
  4032 
  4033 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4034 decision procedure for linear arithmetic. Currently it is used for
  4035 types `nat', `int', and `real' in HOL (see below); it can, should and
  4036 will be instantiated for other types and logics as well.
  4037 
  4038 * The simplifier now accepts rewrite rules with flexible heads, eg
  4039      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4040   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4041   matching.
  4042 
  4043 
  4044 *** General ***
  4045 
  4046 * New Isabelle/Isar subsystem provides an alternative to traditional
  4047 tactical theorem proving; together with the ProofGeneral/isar user
  4048 interface it offers an interactive environment for developing human
  4049 readable proof documents (Isar == Intelligible semi-automated
  4050 reasoning); for further information see isatool doc isar-ref,
  4051 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4052 
  4053 * improved and simplified presentation of theories: better HTML markup
  4054 (including colors), graph views in several sizes; isatool usedir now
  4055 provides a proper interface for user theories (via -P option); actual
  4056 document preparation based on (PDF)LaTeX is available as well (for
  4057 new-style theories only); see isatool doc system for more information;
  4058 
  4059 * native support for Proof General, both for classic Isabelle and
  4060 Isabelle/Isar;
  4061 
  4062 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4063 using the graph browser tool;
  4064 
  4065 * Isabelle manuals now also available as PDF;
  4066 
  4067 * theory loader rewritten from scratch (may not be fully
  4068 bug-compatible); old loadpath variable has been replaced by show_path,
  4069 add_path, del_path, reset_path functions; new operations such as
  4070 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4071 isatool doc ref);
  4072 
  4073 * improved isatool install: option -k creates KDE application icon,
  4074 option -p DIR installs standalone binaries;
  4075 
  4076 * added ML_PLATFORM setting (useful for cross-platform installations);
  4077 more robust handling of platform specific ML images for SML/NJ;
  4078 
  4079 * the settings environment is now statically scoped, i.e. it is never
  4080 created again in sub-processes invoked from isabelle, isatool, or
  4081 Isabelle;
  4082 
  4083 * path element specification '~~' refers to '$ISABELLE_HOME';
  4084 
  4085 * in locales, the "assumes" and "defines" parts may be omitted if
  4086 empty;
  4087 
  4088 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4089 long arrows);
  4090 
  4091 * new print_mode "HTML";
  4092 
  4093 * new flag show_tags controls display of tags of theorems (which are
  4094 basically just comments that may be attached by some tools);
  4095 
  4096 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4097 mode and goal output format:
  4098 
  4099 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4100 244c244
  4101 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4102 ---
  4103 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4104 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4105 181c181
  4106 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4107 ---
  4108 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4109 
  4110 * function bind_thms stores lists of theorems (cf. bind_thm);
  4111 
  4112 * new shorthand tactics ftac, eatac, datac, fatac;
  4113 
  4114 * qed (and friends) now accept "" as result name; in that case the
  4115 theorem is not stored, but proper checks and presentation of the
  4116 result still apply;
  4117 
  4118 * theorem database now also indexes constants "Trueprop", "all",
  4119 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4120 
  4121 
  4122 *** HOL ***
  4123 
  4124 ** HOL arithmetic **
  4125 
  4126 * There are now decision procedures for linear arithmetic over nat and
  4127 int:
  4128 
  4129 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4130 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4131 are treated as atomic; subformulae not involving type `nat' or `int'
  4132 are ignored; quantified subformulae are ignored unless they are
  4133 positive universal or negative existential. The tactic has to be
  4134 invoked by hand and can be a little bit slow. In particular, the
  4135 running time is exponential in the number of occurrences of `min' and
  4136 `max', and `-' on `nat'.
  4137 
  4138 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4139 (negated) (in)equalities among the premises and the conclusion into
  4140 account (i.e. no compound formulae) and does not know about `min' and
  4141 `max', and `-' on `nat'. It is fast and is used automatically by the
  4142 simplifier.
  4143 
  4144 NB: At the moment, these decision procedures do not cope with mixed
  4145 nat/int formulae where the two parts interact, such as `m < n ==>
  4146 int(m) < int(n)'.
  4147 
  4148 * HOL/Numeral provides a generic theory of numerals (encoded
  4149 efficiently as bit strings); setup for types nat/int/real is in place;
  4150 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4151 int, existing theories and proof scripts may require a few additional
  4152 type constraints;
  4153 
  4154 * integer division and remainder can now be performed on constant
  4155 arguments;
  4156 
  4157 * many properties of integer multiplication, division and remainder
  4158 are now available;
  4159 
  4160 * An interface to the Stanford Validity Checker (SVC) is available through the
  4161 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4162 are proved automatically.  SVC must be installed separately, and its results
  4163 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4164 invocation of the underlying oracle).  For SVC see
  4165   http://verify.stanford.edu/SVC
  4166 
  4167 * IsaMakefile: the HOL-Real target now builds an actual image;
  4168 
  4169 
  4170 ** HOL misc **
  4171 
  4172 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4173 (in Isabelle/Isar) -- by Gertrud Bauer;
  4174 
  4175 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4176 analysis for assembly languages with subtypes;
  4177 
  4178 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4179 -- avoids syntactic ambiguities and treats state, transition, and
  4180 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4181 changed syntax and (many) tactics;
  4182 
  4183 * HOL/inductive: Now also handles more general introduction rules such
  4184   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4185   theorems are now maintained within the theory (maintained via the
  4186   "mono" attribute);
  4187 
  4188 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4189   (using function types) such as
  4190 
  4191   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4192 
  4193 * HOL/record: record_simproc (part of the default simpset) takes care
  4194 of selectors applied to updated records; record_split_tac is no longer
  4195 part of the default claset; update_defs may now be removed from the
  4196 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4197 
  4198   claset_ref () := claset() addSWrapper record_split_wrapper;
  4199   Delsimprocs [record_simproc]
  4200 
  4201 * HOL/typedef: fixed type inference for representing set; type
  4202 arguments now have to occur explicitly on the rhs as type constraints;
  4203 
  4204 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4205 names rather than an ML expression;
  4206 
  4207 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4208 supplied later.  Program schemes can be defined, such as
  4209     "While B C s = (if B s then While B C (C s) else s)"
  4210 where the well-founded relation can be chosen after B and C have been given.
  4211 
  4212 * HOL/List: the constructors of type list are now Nil and Cons;
  4213 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4214 course, ML tools referring to List.list.op # etc. have to be adapted;
  4215 
  4216 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4217 disabled by default; run isabelle with option -m HOL to get back to
  4218 the original Gordon/HOL-style output;
  4219 
  4220 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4221 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4222 
  4223 * HOL basic syntax simplified (more orthogonal): all variants of
  4224 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4225 Eps operator is provided as well: "SOME x. P[x]";
  4226 
  4227 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4228 
  4229 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4230 thus available for user theories;
  4231 
  4232 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4233 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4234 time;
  4235 
  4236 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4237 several times and then mp;
  4238 
  4239 
  4240 *** LK ***
  4241 
  4242 * the notation <<...>> is now available as a notation for sequences of
  4243 formulas;
  4244 
  4245 * the simplifier is now installed
  4246 
  4247 * the axiom system has been generalized (thanks to Soren Heilmann)
  4248 
  4249 * the classical reasoner now has a default rule database
  4250 
  4251 
  4252 *** ZF ***
  4253 
  4254 * new primrec section allows primitive recursive functions to be given
  4255 directly (as in HOL) over datatypes and the natural numbers;
  4256 
  4257 * new tactics induct_tac and exhaust_tac for induction (or case
  4258 analysis) over datatypes and the natural numbers;
  4259 
  4260 * the datatype declaration of type T now defines the recursor T_rec;
  4261 
  4262 * simplification automatically does freeness reasoning for datatype
  4263 constructors;
  4264 
  4265 * automatic type-inference, with AddTCs command to insert new
  4266 type-checking rules;
  4267 
  4268 * datatype introduction rules are now added as Safe Introduction rules
  4269 to the claset;
  4270 
  4271 * the syntax "if P then x else y" is now available in addition to
  4272 if(P,x,y);
  4273 
  4274 
  4275 *** Internal programming interfaces ***
  4276 
  4277 * tuned simplifier trace output; new flag debug_simp;
  4278 
  4279 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4280 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4281 
  4282 * AxClass.axclass_tac lost the theory argument;
  4283 
  4284 * tuned current_goals_markers semantics: begin / end goal avoids
  4285 printing empty lines;
  4286 
  4287 * removed prs and prs_fn hook, which was broken because it did not
  4288 include \n in its semantics, forcing writeln to add one
  4289 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4290 string -> unit if you really want to output text without newline;
  4291 
  4292 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4293 plain output, interface builders may have to enable 'isabelle_font'
  4294 mode to get Isabelle font glyphs as before;
  4295 
  4296 * refined token_translation interface; INCOMPATIBILITY: output length
  4297 now of type real instead of int;
  4298 
  4299 * theory loader actions may be traced via new ThyInfo.add_hook
  4300 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4301 your own database of information attached to *whole* theories -- as
  4302 opposed to intra-theory data slots offered via TheoryDataFun;
  4303 
  4304 * proper handling of dangling sort hypotheses (at last!);
  4305 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4306 extra sort hypotheses that can be witnessed from the type signature;
  4307 the force_strip_shyps flag is gone, any remaining shyps are simply
  4308 left in the theorem (with a warning issued by strip_shyps_warning);
  4309 
  4310 
  4311 
  4312 New in Isabelle98-1 (October 1998)
  4313 ----------------------------------
  4314 
  4315 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4316 
  4317 * several changes of automated proof tools;
  4318 
  4319 * HOL: major changes to the inductive and datatype packages, including
  4320 some minor incompatibilities of theory syntax;
  4321 
  4322 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4323 called `inj_on';
  4324 
  4325 * HOL: removed duplicate thms in Arith:
  4326   less_imp_add_less  should be replaced by  trans_less_add1
  4327   le_imp_add_le      should be replaced by  trans_le_add1
  4328 
  4329 * HOL: unary minus is now overloaded (new type constraints may be
  4330 required);
  4331 
  4332 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4333 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4334 now taken as an integer constant.
  4335 
  4336 * Pure: ML function 'theory_of' renamed to 'theory';
  4337 
  4338 
  4339 *** Proof tools ***
  4340 
  4341 * Simplifier:
  4342   1. Asm_full_simp_tac is now more aggressive.
  4343      1. It will sometimes reorient premises if that increases their power to
  4344         simplify.
  4345      2. It does no longer proceed strictly from left to right but may also
  4346         rotate premises to achieve further simplification.
  4347      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4348      old Asm_full_simp_tac in that it does not rotate premises.
  4349   2. The simplifier now knows a little bit about nat-arithmetic.
  4350 
  4351 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4352 allows for selected deletion of wrappers, by introduction of names for
  4353 wrapper functionals.  This implies that addbefore, addSbefore,
  4354 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4355 and that adding two tactics with the same name overwrites the first
  4356 one (emitting a warning).
  4357   type wrapper = (int -> tactic) -> (int -> tactic)
  4358   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4359   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4360   delWrapper, delSWrapper: claset *  string            -> claset
  4361   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4362 
  4363 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4364 semantics; addbefore now affects only the unsafe part of step_tac
  4365 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4366 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4367 by Force_tac;
  4368 
  4369 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4370 compWrapper; added safe wrapper (and access functions for it);
  4371 
  4372 * HOL/split_all_tac is now much faster and fails if there is nothing
  4373 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4374 and the names of the automatically generated variables have changed.
  4375 split_all_tac has moved within claset() from unsafe wrappers to safe
  4376 wrappers, which means that !!-bound variables are split much more
  4377 aggressively, and safe_tac and clarify_tac now split such variables.
  4378 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4379 Note: the same holds for record_split_tac, which does the job of
  4380 split_all_tac for record fields.
  4381 
  4382 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4383 permanently to the default simpset using Addsplits just like
  4384 Addsimps. They can be removed via Delsplits just like
  4385 Delsimps. Lower-case versions are also available.
  4386 
  4387 * HOL/Simplifier: The rule split_if is now part of the default
  4388 simpset. This means that the simplifier will eliminate all occurrences
  4389 of if-then-else in the conclusion of a goal. To prevent this, you can
  4390 either remove split_if completely from the default simpset by
  4391 `Delsplits [split_if]' or remove it in a specific call of the
  4392 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4393 other case splitting rules to/from the default simpset: every datatype
  4394 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4395 t is the name of the datatype).
  4396 
  4397 * Classical reasoner / Simplifier combination: new force_tac (and
  4398 derivatives Force_tac, force) combines rewriting and classical
  4399 reasoning (and whatever other tools) similarly to auto_tac, but is
  4400 aimed to solve the given subgoal completely.
  4401 
  4402 
  4403 *** General ***
  4404 
  4405 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4406 and `goalw': the theory is no longer needed as an explicit argument -
  4407 the current theory context is used; assumptions are no longer returned
  4408 at the ML-level unless one of them starts with ==> or !!; it is
  4409 recommended to convert to these new commands using isatool fixgoal
  4410 (backup your sources first!);
  4411 
  4412 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4413 the current theory context, and 'theory' to lookup stored theories;
  4414 
  4415 * new theory section 'locale' for declaring constants, assumptions and
  4416 definitions that have local scope;
  4417 
  4418 * new theory section 'nonterminals' for purely syntactic types;
  4419 
  4420 * new theory section 'setup' for generic ML setup functions
  4421 (e.g. package initialization);
  4422 
  4423 * the distribution now includes Isabelle icons: see
  4424 lib/logo/isabelle-{small,tiny}.xpm;
  4425 
  4426 * isatool install - install binaries with absolute references to
  4427 ISABELLE_HOME/bin;
  4428 
  4429 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4430 
  4431 * print mode 'emacs' reserved for Isamode;
  4432 
  4433 * support multiple print (ast) translations per constant name;
  4434 
  4435 * theorems involving oracles are now printed with a suffixed [!];
  4436 
  4437 
  4438 *** HOL ***
  4439 
  4440 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4441 
  4442 * HOL/inductive package reorganized and improved: now supports mutual
  4443 definitions such as
  4444 
  4445   inductive EVEN ODD
  4446     intrs
  4447       null "0 : EVEN"
  4448       oddI "n : EVEN ==> Suc n : ODD"
  4449       evenI "n : ODD ==> Suc n : EVEN"
  4450 
  4451 new theorem list "elims" contains an elimination rule for each of the
  4452 recursive sets; inductive definitions now handle disjunctive premises
  4453 correctly (also ZF);
  4454 
  4455 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4456 "mutual_induct" no longer exists - the induction rule is always
  4457 contained in "induct";
  4458 
  4459 
  4460 * HOL/datatype package re-implemented and greatly improved: now
  4461 supports mutually recursive datatypes such as
  4462 
  4463   datatype
  4464     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4465             | SUM ('a aexp) ('a aexp)
  4466             | DIFF ('a aexp) ('a aexp)
  4467             | NUM 'a
  4468   and
  4469     'a bexp = LESS ('a aexp) ('a aexp)
  4470             | AND ('a bexp) ('a bexp)
  4471             | OR ('a bexp) ('a bexp)
  4472 
  4473 as well as indirectly recursive datatypes such as
  4474 
  4475   datatype
  4476     ('a, 'b) term = Var 'a
  4477                   | App 'b ((('a, 'b) term) list)
  4478 
  4479 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4480 induction on mutually / indirectly recursive datatypes.
  4481 
  4482 Primrec equations are now stored in theory and can be accessed via
  4483 <function_name>.simps.
  4484 
  4485 INCOMPATIBILITIES:
  4486 
  4487   - Theories using datatypes must now have theory Datatype as an
  4488     ancestor.
  4489   - The specific <typename>.induct_tac no longer exists - use the
  4490     generic induct_tac instead.
  4491   - natE has been renamed to nat.exhaust - use exhaust_tac
  4492     instead of res_inst_tac ... natE. Note that the variable
  4493     names in nat.exhaust differ from the names in natE, this
  4494     may cause some "fragile" proofs to fail.
  4495   - The theorems split_<typename>_case and split_<typename>_case_asm
  4496     have been renamed to <typename>.split and <typename>.split_asm.
  4497   - Since default sorts of type variables are now handled correctly,
  4498     some datatype definitions may have to be annotated with explicit
  4499     sort constraints.
  4500   - Primrec definitions no longer require function name and type
  4501     of recursive argument.
  4502 
  4503 Consider using isatool fixdatatype to adapt your theories and proof
  4504 scripts to the new package (backup your sources first!).
  4505 
  4506 
  4507 * HOL/record package: considerably improved implementation; now
  4508 includes concrete syntax for record types, terms, updates; theorems
  4509 for surjective pairing and splitting !!-bound record variables; proof
  4510 support is as follows:
  4511 
  4512   1) standard conversions (selectors or updates applied to record
  4513 constructor terms) are part of the standard simpset;
  4514 
  4515   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4516 made part of standard simpset and claset via addIffs;
  4517 
  4518   3) a tactic for record field splitting (record_split_tac) is part of
  4519 the standard claset (addSWrapper);
  4520 
  4521 To get a better idea about these rules you may retrieve them via
  4522 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4523 the name of your record type.
  4524 
  4525 The split tactic 3) conceptually simplifies by the following rule:
  4526 
  4527   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4528 
  4529 Thus any record variable that is bound by meta-all will automatically
  4530 blow up into some record constructor term, consequently the
  4531 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4532 solve record problems automatically.
  4533 
  4534 
  4535 * reorganized the main HOL image: HOL/Integ and String loaded by
  4536 default; theory Main includes everything;
  4537 
  4538 * automatic simplification of integer sums and comparisons, using cancellation;
  4539 
  4540 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4541 
  4542 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4543 
  4544 * many new identities for unions, intersections, set difference, etc.;
  4545 
  4546 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4547 called split_if, split_split, split_sum_case and split_nat_case (to go
  4548 with add/delsplits);
  4549 
  4550 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4551 (?x::unit) = (); this is made part of the default simpset, which COULD
  4552 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4553 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4554 unit_abs_eta_conv is added in order to counter the effect of
  4555 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4556 %u.f();
  4557 
  4558 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4559 makes more sense);
  4560 
  4561 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4562   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4563   disjointness reasoning but breaking a few old proofs.
  4564 
  4565 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4566 to 'converse' from 'inverse' (for compatibility with ZF and some
  4567 literature);
  4568 
  4569 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4570 the well-founded relation;
  4571 
  4572 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4573     Compl A.  The "Compl" syntax remains available as input syntax for this
  4574     release ONLY.
  4575 
  4576 * HOL/Update: new theory of function updates:
  4577     f(a:=b) == %x. if x=a then b else f x
  4578 may also be iterated as in f(a:=b,c:=d,...);
  4579 
  4580 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4581 
  4582 * HOL/List:
  4583   - new function list_update written xs[i:=v] that updates the i-th
  4584     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4585   - new function `upt' written [i..j(] which generates the list
  4586     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4587     bound write [i..j], which is a shorthand for [i..j+1(].
  4588   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4589 
  4590 * HOL/Arith:
  4591   - removed 'pred' (predecessor) function;
  4592   - generalized some theorems about n-1;
  4593   - many new laws about "div" and "mod";
  4594   - new laws about greatest common divisors (see theory ex/Primes);
  4595 
  4596 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4597 instead of "inverse";
  4598 
  4599 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4600   of the multiset ordering;
  4601 
  4602 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4603   (not included by default);
  4604 
  4605 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4606 
  4607 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4608   programs, i.e. different program variables may have different types.
  4609 
  4610 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4611   [previously, this check worked only if the rewrite rule was unconditional]
  4612   Now rew can involve either definitions or equalities (either == or =).
  4613 
  4614 
  4615 *** ZF ***
  4616 
  4617 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4618   only the theorems proved on ZF.ML;
  4619 
  4620 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4621   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4622   disjointness reasoning but breaking a few old proofs.
  4623 
  4624 * ZF/Update: new theory of function updates
  4625     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4626   may also be iterated as in f(a:=b,c:=d,...);
  4627 
  4628 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4629 
  4630 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4631   [previously, this check worked only if the rewrite rule was unconditional]
  4632   Now rew can involve either definitions or equalities (either == or =).
  4633 
  4634 * case_tac provided for compatibility with HOL
  4635     (like the old excluded_middle_tac, but with subgoals swapped)
  4636 
  4637 
  4638 *** Internal programming interfaces ***
  4639 
  4640 * Pure: several new basic modules made available for general use, see
  4641 also src/Pure/README;
  4642 
  4643 * improved the theory data mechanism to support encapsulation (data
  4644 kind name replaced by private Object.kind, acting as authorization
  4645 key); new type-safe user interface via functor TheoryDataFun; generic
  4646 print_data function becomes basically useless;
  4647 
  4648 * removed global_names compatibility flag -- all theory declarations
  4649 are qualified by default;
  4650 
  4651 * module Pure/Syntax now offers quote / antiquote translation
  4652 functions (useful for Hoare logic etc. with implicit dependencies);
  4653 see HOL/ex/Antiquote for an example use;
  4654 
  4655 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4656 cterm -> thm;
  4657 
  4658 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4659 subgoal;
  4660 
  4661 * Display.print_goals function moved to Locale.print_goals;
  4662 
  4663 * standard print function for goals supports current_goals_markers
  4664 variable for marking begin of proof, end of proof, start of goal; the
  4665 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4666 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4667 for example;
  4668 
  4669 
  4670 
  4671 New in Isabelle98 (January 1998)
  4672 --------------------------------
  4673 
  4674 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4675 
  4676 * changed lexical syntax of terms / types: dots made part of long
  4677 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4678 
  4679 * simpset (and claset) reference variable replaced by functions
  4680 simpset / simpset_ref;
  4681 
  4682 * no longer supports theory aliases (via merge) and non-trivial
  4683 implicit merge of thms' signatures;
  4684 
  4685 * most internal names of constants changed due to qualified names;
  4686 
  4687 * changed Pure/Sequence interface (see Pure/seq.ML);
  4688 
  4689 
  4690 *** General Changes ***
  4691 
  4692 * hierachically structured name spaces (for consts, types, axms, thms
  4693 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4694 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4695 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4696 long_names for fully qualified output names; NOTE: ML programs
  4697 (special tactics, packages etc.) referring to internal names may have
  4698 to be adapted to cope with fully qualified names; in case of severe
  4699 backward campatibility problems try setting 'global_names' at compile
  4700 time to have enrything declared within a flat name space; one may also
  4701 fine tune name declarations in theories via the 'global' and 'local'
  4702 section;
  4703 
  4704 * reimplemented the implicit simpset and claset using the new anytype
  4705 data filed in signatures; references simpset:simpset ref etc. are
  4706 replaced by functions simpset:unit->simpset and
  4707 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4708 to patch your ML files accordingly;
  4709 
  4710 * HTML output now includes theory graph data for display with Java
  4711 applet or isatool browser; data generated automatically via isatool
  4712 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4713 
  4714 * defs may now be conditional; improved rewrite_goals_tac to handle
  4715 conditional equations;
  4716 
  4717 * defs now admits additional type arguments, using TYPE('a) syntax;
  4718 
  4719 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4720 creates a new theory node; implicit merge of thms' signatures is
  4721 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4722 transfer:theory->thm->thm in (rare) cases;
  4723 
  4724 * improved handling of draft signatures / theories; draft thms (and
  4725 ctyps, cterms) are automatically promoted to real ones;
  4726 
  4727 * slightly changed interfaces for oracles: admit many per theory, named
  4728 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4729 
  4730 * print_goals: optional output of const types (set show_consts and
  4731 show_types);
  4732 
  4733 * improved output of warnings (###) and errors (***);
  4734 
  4735 * subgoal_tac displays a warning if the new subgoal has type variables;
  4736 
  4737 * removed old README and Makefiles;
  4738 
  4739 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4740 
  4741 * removed obsolete init_pps and init_database;
  4742 
  4743 * deleted the obsolete tactical STATE, which was declared by
  4744     fun STATE tacfun st = tacfun st st;
  4745 
  4746 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4747 (which abbreviates $HOME);
  4748 
  4749 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4750 use isatool fixseq to adapt your ML programs (this works for fully
  4751 qualified references to the Sequence structure only!);
  4752 
  4753 * use_thy no longer requires writable current directory; it always
  4754 reloads .ML *and* .thy file, if either one is out of date;
  4755 
  4756 
  4757 *** Classical Reasoner ***
  4758 
  4759 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4760 tactics that use classical reasoning to simplify a subgoal without
  4761 splitting it into several subgoals;
  4762 
  4763 * Safe_tac: like safe_tac but uses the default claset;
  4764 
  4765 
  4766 *** Simplifier ***
  4767 
  4768 * added simplification meta rules:
  4769     (asm_)(full_)simplify: simpset -> thm -> thm;
  4770 
  4771 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4772 logics (again);
  4773 
  4774 * added prems argument to simplification procedures;
  4775 
  4776 * HOL, FOL, ZF: added infix function `addsplits':
  4777   instead of `<simpset> setloop (split_tac <thms>)'
  4778   you can simply write `<simpset> addsplits <thms>'
  4779 
  4780 
  4781 *** Syntax ***
  4782 
  4783 * TYPE('a) syntax for type reflection terms;
  4784 
  4785 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4786 
  4787 * pretty printer: changed order of mixfix annotation preference (again!);
  4788 
  4789 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4790 
  4791 
  4792 *** HOL ***
  4793 
  4794 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4795   with `addloop' of the simplifier to faciliate case splitting in premises.
  4796 
  4797 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4798 
  4799 * HOL/Auth: new protocol proofs including some for the Internet
  4800   protocol TLS;
  4801 
  4802 * HOL/Map: new theory of `maps' a la VDM;
  4803 
  4804 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4805 cancelling out common nat summands from =, <, <= (in)equalities, or
  4806 differences; simplification procedures nat_cancel_factor for
  4807 cancelling common factor from =, <, <= (in)equalities over natural
  4808 sums; nat_cancel contains both kinds of procedures, it is installed by
  4809 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4810 
  4811 * HOL/simplifier: terms of the form
  4812   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4813   are rewritten to
  4814   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4815   and those of the form
  4816   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4817   are rewritten to
  4818   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4819 
  4820 * HOL/datatype
  4821   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4822 
  4823   P(t_case f1 ... fn x) =
  4824      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4825         ...
  4826        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4827      )
  4828 
  4829   and a theorem `split_t_case_asm' of the form
  4830 
  4831   P(t_case f1 ... fn x) =
  4832     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4833         ...
  4834        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4835      )
  4836   which can be added to a simpset via `addsplits'. The existing theorems
  4837   expand_list_case and expand_option_case have been renamed to
  4838   split_list_case and split_option_case.
  4839 
  4840 * HOL/Arithmetic:
  4841   - `pred n' is automatically converted to `n-1'.
  4842     Users are strongly encouraged not to use `pred' any longer,
  4843     because it will disappear altogether at some point.
  4844   - Users are strongly encouraged to write "0 < n" rather than
  4845     "n ~= 0". Theorems and proof tools have been modified towards this
  4846     `standard'.
  4847 
  4848 * HOL/Lists:
  4849   the function "set_of_list" has been renamed "set" (and its theorems too);
  4850   the function "nth" now takes its arguments in the reverse order and
  4851   has acquired the infix notation "!" as in "xs!n".
  4852 
  4853 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4854 
  4855 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4856   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4857 
  4858 * HOL/record: extensible records with schematic structural subtyping
  4859 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4860 still lacks various theorems and concrete record syntax;
  4861 
  4862 
  4863 *** HOLCF ***
  4864 
  4865 * removed "axioms" and "generated by" sections;
  4866 
  4867 * replaced "ops" section by extended "consts" section, which is capable of
  4868   handling the continuous function space "->" directly;
  4869 
  4870 * domain package:
  4871   . proves theorems immediately and stores them in the theory,
  4872   . creates hierachical name space,
  4873   . now uses normal mixfix annotations (instead of cinfix...),
  4874   . minor changes to some names and values (for consistency),
  4875   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4876   . separator between mutual domain defs: changed "," to "and",
  4877   . improved handling of sort constraints;  now they have to
  4878     appear on the left-hand side of the equations only;
  4879 
  4880 * fixed LAM <x,y,zs>.b syntax;
  4881 
  4882 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4883 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4884 
  4885 
  4886 *** FOL and ZF ***
  4887 
  4888 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4889   with `addloop' of the simplifier to faciliate case splitting in premises.
  4890 
  4891 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4892 in HOL, they strip ALL and --> from proved theorems;
  4893 
  4894 
  4895 
  4896 New in Isabelle94-8 (May 1997)
  4897 ------------------------------
  4898 
  4899 *** General Changes ***
  4900 
  4901 * new utilities to build / run / maintain Isabelle etc. (in parts
  4902 still somewhat experimental); old Makefiles etc. still functional;
  4903 
  4904 * new 'Isabelle System Manual';
  4905 
  4906 * INSTALL text, together with ./configure and ./build scripts;
  4907 
  4908 * reimplemented type inference for greater efficiency, better error
  4909 messages and clean internal interface;
  4910 
  4911 * prlim command for dealing with lots of subgoals (an easier way of
  4912 setting goals_limit);
  4913 
  4914 
  4915 *** Syntax ***
  4916 
  4917 * supports alternative (named) syntax tables (parser and pretty
  4918 printer); internal interface is provided by add_modesyntax(_i);
  4919 
  4920 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4921 be used in conjunction with the Isabelle symbol font; uses the
  4922 "symbols" syntax table;
  4923 
  4924 * added token_translation interface (may translate name tokens in
  4925 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4926 the current print_mode); IMPORTANT: user print translation functions
  4927 are responsible for marking newly introduced bounds
  4928 (Syntax.mark_boundT);
  4929 
  4930 * token translations for modes "xterm" and "xterm_color" that display
  4931 names in bold, underline etc. or colors (which requires a color
  4932 version of xterm);
  4933 
  4934 * infixes may now be declared with names independent of their syntax;
  4935 
  4936 * added typed_print_translation (like print_translation, but may
  4937 access type of constant);
  4938 
  4939 
  4940 *** Classical Reasoner ***
  4941 
  4942 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4943 some limitations.  Blast_tac...
  4944   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4945   + ignores elimination rules that don't have the correct format
  4946         (the conclusion MUST be a formula variable)
  4947   + ignores types, which can make HOL proofs fail
  4948   + rules must not require higher-order unification, e.g. apply_type in ZF
  4949     [message "Function Var's argument not a bound variable" relates to this]
  4950   + its proof strategy is more general but can actually be slower
  4951 
  4952 * substitution with equality assumptions no longer permutes other
  4953 assumptions;
  4954 
  4955 * minor changes in semantics of addafter (now called addaltern); renamed
  4956 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4957 (and access functions for it);
  4958 
  4959 * improved combination of classical reasoner and simplifier:
  4960   + functions for handling clasimpsets
  4961   + improvement of addss: now the simplifier is called _after_ the
  4962     safe steps.
  4963   + safe variant of addss called addSss: uses safe simplifications
  4964     _during_ the safe steps. It is more complete as it allows multiple
  4965     instantiations of unknowns (e.g. with slow_tac).
  4966 
  4967 *** Simplifier ***
  4968 
  4969 * added interface for simplification procedures (functions that
  4970 produce *proven* rewrite rules on the fly, depending on current
  4971 redex);
  4972 
  4973 * ordering on terms as parameter (used for ordered rewriting);
  4974 
  4975 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4976 
  4977 * the solver is now split into a safe and an unsafe part.
  4978 This should be invisible for the normal user, except that the
  4979 functions setsolver and addsolver have been renamed to setSolver and
  4980 addSolver; added safe_asm_full_simp_tac;
  4981 
  4982 
  4983 *** HOL ***
  4984 
  4985 * a generic induction tactic `induct_tac' which works for all datatypes and
  4986 also for type `nat';
  4987 
  4988 * a generic case distinction tactic `exhaust_tac' which works for all
  4989 datatypes and also for type `nat';
  4990 
  4991 * each datatype comes with a function `size';
  4992 
  4993 * patterns in case expressions allow tuple patterns as arguments to
  4994 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4995 
  4996 * primrec now also works with type nat;
  4997 
  4998 * recdef: a new declaration form, allows general recursive functions to be
  4999 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5000 
  5001 * the constant for negation has been renamed from "not" to "Not" to
  5002 harmonize with FOL, ZF, LK, etc.;
  5003 
  5004 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5005 infinite lists;
  5006 
  5007 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5008 
  5009 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5010 problems in commutative rings, using axiomatic type classes for + and *;
  5011 
  5012 * more examples in HOL/MiniML and HOL/Auth;
  5013 
  5014 * more default rewrite rules for quantifiers, union/intersection;
  5015 
  5016 * a new constant `arbitrary == @x.False';
  5017 
  5018 * HOLCF/IOA replaces old HOL/IOA;
  5019 
  5020 * HOLCF changes: derived all rules and arities
  5021   + axiomatic type classes instead of classes
  5022   + typedef instead of faking type definitions
  5023   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5024   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5025   + eliminated the types void, one, tr
  5026   + use unit lift and bool lift (with translations) instead of one and tr
  5027   + eliminated blift from Lift3.thy (use Def instead of blift)
  5028   all eliminated rules are derived as theorems --> no visible changes ;
  5029 
  5030 
  5031 *** ZF ***
  5032 
  5033 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5034 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5035 as ZF_cs addSIs [equalityI];
  5036 
  5037 
  5038 
  5039 New in Isabelle94-7 (November 96)
  5040 ---------------------------------
  5041 
  5042 * allowing negative levels (as offsets) in prlev and choplev;
  5043 
  5044 * super-linear speedup for large simplifications;
  5045 
  5046 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5047 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5048 FAIL); can suppress it using the command Delsimps (ex_simps @
  5049 all_simps); De Morgan laws are also now included, by default;
  5050 
  5051 * improved printing of ==>  :  ~:
  5052 
  5053 * new object-logic "Sequents" adds linear logic, while replacing LK
  5054 and Modal (thanks to Sara Kalvala);
  5055 
  5056 * HOL/Auth: correctness proofs for authentication protocols;
  5057 
  5058 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5059 examples on HOL/Auth);
  5060 
  5061 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5062 the rewriter and classical reasoner simultaneously;
  5063 
  5064 * function uresult no longer returns theorems in "standard" format;
  5065 regain previous version by: val uresult = standard o uresult;
  5066 
  5067 
  5068 
  5069 New in Isabelle94-6
  5070 -------------------
  5071 
  5072 * oracles -- these establish an interface between Isabelle and trusted
  5073 external reasoners, which may deliver results as theorems;
  5074 
  5075 * proof objects (in particular record all uses of oracles);
  5076 
  5077 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5078 
  5079 * "constdefs" section in theory files;
  5080 
  5081 * "primrec" section (HOL) no longer requires names;
  5082 
  5083 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5084 
  5085 
  5086 
  5087 New in Isabelle94-5
  5088 -------------------
  5089 
  5090 * reduced space requirements;
  5091 
  5092 * automatic HTML generation from theories;
  5093 
  5094 * theory files no longer require "..." (quotes) around most types;
  5095 
  5096 * new examples, including two proofs of the Church-Rosser theorem;
  5097 
  5098 * non-curried (1994) version of HOL is no longer distributed;
  5099 
  5100 
  5101 
  5102 New in Isabelle94-4
  5103 -------------------
  5104 
  5105 * greatly reduced space requirements;
  5106 
  5107 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5108 
  5109 * searchable theorem database (see the section "Retrieving theorems" on
  5110 page 8 of the Reference Manual);
  5111 
  5112 * new examples, including Grabczewski's monumental case study of the
  5113 Axiom of Choice;
  5114 
  5115 * The previous version of HOL renamed to Old_HOL;
  5116 
  5117 * The new version of HOL (previously called CHOL) uses a curried syntax
  5118 for functions.  Application looks like f a b instead of f(a,b);
  5119 
  5120 * Mutually recursive inductive definitions finally work in HOL;
  5121 
  5122 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5123 translates to the operator "split";
  5124 
  5125 
  5126 
  5127 New in Isabelle94-3
  5128 -------------------
  5129 
  5130 * new infix operator, addss, allowing the classical reasoner to
  5131 perform simplification at each step of its search.  Example:
  5132         fast_tac (cs addss ss)
  5133 
  5134 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5135 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5136 look like (a,b) instead of <a,b>;
  5137 
  5138 * PLEASE NOTE: CHOL will eventually replace HOL!
  5139 
  5140 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5141 It translates to the operator "split".  A new theory of integers is available;
  5142 
  5143 * In ZF, integer numerals now denote two's-complement binary integers.
  5144 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5145 
  5146 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5147 of the Axiom of Choice;
  5148 
  5149 
  5150 
  5151 New in Isabelle94-2
  5152 -------------------
  5153 
  5154 * Significantly faster resolution;
  5155 
  5156 * the different sections in a .thy file can now be mixed and repeated
  5157 freely;
  5158 
  5159 * Database of theorems for FOL, HOL and ZF.  New
  5160 commands including qed, qed_goal and bind_thm store theorems in the database.
  5161 
  5162 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5163 a given theory (thms_of), or find out what theory a theorem was proved in
  5164 (theory_of_thm);
  5165 
  5166 * Bugs fixed in the inductive definition and datatype packages;
  5167 
  5168 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5169 and HOL_dup_cs obsolete;
  5170 
  5171 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5172 have been removed;
  5173 
  5174 * Simpler definition of function space in ZF;
  5175 
  5176 * new results about cardinal and ordinal arithmetic in ZF;
  5177 
  5178 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5179 types;
  5180 
  5181 :mode=text:wrap=hard:maxLineLen=72:
  5182 $Id$