NEWS
author wenzelm
Wed Mar 19 22:47:39 2008 +0100 (2008-03-19 ago)
changeset 26341 2f5a4367a39e
parent 26335 961bbcc9d85b
child 26355 9276633fdc24
permissions -rw-r--r--
avoid Auto_tac;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Syntax: symbol \<chi> is now considered a letter.  Potential
    10 INCOMPATIBILITY in identifier syntax etc.
    11 
    12 * Outer syntax: string tokens may contain arbitrary character codes
    13 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
    14 "foo_bar".
    15 
    16 * Outer syntax: string tokens no longer admit escaped white space,
    17 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
    18 white space directly.
    19 
    20 * Theory loader: use_thy (and similar operations) no longer set the
    21 implicit ML context, which was occasionally hard to predict and in
    22 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
    23 provides a proper context already.
    24 
    25 * Theory loader: old-style ML proof scripts being *attached* to a thy
    26 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
    27 'use' within a theory file will do the job.
    28 
    29 
    30 *** Pure ***
    31 
    32 * Instantiation target allows for simultaneous specification of class
    33 instance operations together with an instantiation proof.
    34 Type-checking phase allows to refer to class operations uniformly.
    35 See HOL/Complex/Complex.thy for an Isar example and
    36 HOL/Library/Eval.thy for an ML example.
    37 
    38 * Indexing of literal facts: be more serious about including only
    39 facts from the visible specification/proof context, but not the
    40 background context (locale etc.).  Affects `prop` notation and method
    41 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
    42 situations.
    43 
    44 
    45 *** HOL ***
    46 
    47 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
    48 the same name in theory Orderings:
    49 
    50   less_trans
    51   less_linear
    52   le_imp_less_or_eq
    53   le_less_trans
    54   less_le_trans
    55   less_not_sym
    56   less_asym
    57 
    58 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
    59 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
    60 and different variable names.
    61 
    62 * Library/Option_ord.thy: Canonical order on option type.
    63 
    64 * Library/RBT.thy: New theory of red-black trees, an efficient
    65 implementation of finite maps.
    66 
    67 * Library/Countable.thy: Type class for countable types.
    68 
    69 * Theory Int: The representation of numerals has changed.  The infix
    70 operator BIT and the bit datatype with constructors B0 and B1 have
    71 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
    72 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
    73 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
    74 accordingly.
    75 
    76 * Theory Nat: definition of <= and < on natural numbers no longer
    77 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
    78 le_def and less_def have disappeared.  Consider lemmas not_less
    79 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
    80 
    81 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
    82 (whose purpose mainly is for various fold_set functionals) have been
    83 abandoned in favour of the existing algebraic classes
    84 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
    85 lower_semilattice (resp. upper_semilattice) and linorder.
    86 INCOMPATIBILITY.
    87 
    88 * Theory Transitive_Closure: induct and cases rules now declare proper
    89 case_names ("base" and "step").  INCOMPATIBILITY.
    90 
    91 * Theorem Inductive.lfp_ordinal_induct generalized to complete
    92 lattices.  The form set-specific version is available as
    93 Inductive.lfp_ordinal_induct_set.
    94 
    95 * Theorems "power.simps" renamed to "power_int.simps".
    96 
    97 * Class semiring_div provides basic abstract properties of semirings
    98 with division and modulo operations.  Subsumes former class dvd_mod.
    99 
   100 * Merged theories IntDef, Numeral and IntArith into unified theory
   101 Int.  INCOMPATIBILITY.
   102 
   103 * Theory Library/Code_Index: type "index" now represents natural
   104 numbers rather than integers.  INCOMPATIBILITY.
   105 
   106 * New class "uminus" with operation "uminus" (split of from class
   107 "minus" which now only has operation "minus", binary).
   108 INCOMPATIBILITY.
   109 
   110 * New primrec package.  Specification syntax conforms in style to
   111 definition/function/....  No separate induction rule is provided.  The
   112 "primrec" command distinguishes old-style and new-style specifications
   113 by syntax.  The former primrec package is now named OldPrimrecPackage.
   114 When adjusting theories, beware: constants stemming for new-style
   115 primrec specifications have authentic syntax.
   116 
   117 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
   118 
   119 * Library/ListVector: new theory of arithmetic vector operations.
   120 
   121 * Constants "card", "internal_split", "option_map" now with authentic
   122 syntax.  INCOMPATIBILITY.
   123 
   124 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
   125 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
   126 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
   127 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
   128 Sup_set_def, le_def, less_def, option_map_def now with object
   129 equality.  INCOMPATIBILITY.
   130 
   131 * Method "induction_scheme" derives user-specified induction rules
   132 from wellfounded induction and completeness of patterns. This factors
   133 out some operations that are done internally by the function package
   134 and makes them available separately. See "HOL/ex/Induction_Scheme.thy"
   135 for examples,
   136 
   137 * Records. Removed K_record, and replaced it by pure lambda term
   138 %x. c. The simplifier setup is now more robust against eta expansion.
   139 INCOMPATIBILITY: in cases explicitly referring to K_record.
   140 
   141 * Metis prover is now an order of magnitude faster, and also works
   142 with multithreading.
   143 
   144 * Sledgehammer no longer produces structured proofs by default. To enable, 
   145 declare [[sledgehammer_full = true]]. Attributes reconstruction_modulus,  
   146 reconstruction_sorts renamed sledgehammer_modulus, sledgehammer_sorts. 
   147 INCOMPATIBILITY.
   148 
   149 *** ZF ***
   150 
   151 * Renamed theories:
   152 
   153   Datatype.thy  -> Datatype_ZF.thy
   154   Inductive.thy -> Inductive_ZF.thy
   155   Int.thy       -> Int_ZF.thy
   156   IntDiv.thy    -> IntDiv_ZF.thy
   157   Nat.thy       -> Nat_ZF.thy
   158   List.thy      -> List_ZF.thy
   159   Main.thy      -> Main_ZF.thy
   160 
   161  This is to allow to load both ZF and HOL in the same session.
   162 
   163  INCOMPATIBILITY: ZF theories that import individual theories below
   164  Main might need to be adapted. For compatibility, a new 
   165  "theory Main imports Main_ZF begin end" is provided, so if you just
   166  imported "Main", no changes are needed.
   167 
   168 
   169 *** ML ***
   170 
   171 * ML within Isar: antiquotation @{const name} or @{const
   172 name(typargs)} produces statically-checked Const term.
   173 
   174 * The ``print mode'' is now a thread-local value derived from a global
   175 template (the former print_mode reference), thus access becomes
   176 non-critical.  The global print_mode reference is for session
   177 management only; user-code should use print_mode_value,
   178 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
   179 
   180 * system/system_out provides a robust way to invoke external shell
   181 commands, with propagation of interrupts (after Poly/ML 5.2).  Do not
   182 use OS.Process.system etc. directly.
   183 
   184 
   185 *** System ***
   186 
   187 * System: removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the
   188 documented way of changing the user's settings is via
   189 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
   190 script.
   191 
   192 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
   193 in accordance with Proof General 3.7, which prefers GNU emacs.
   194 
   195 * Multithreading.max_threads := 0 refers to the number of actual CPU
   196 cores of the underlying machine, which is a good starting point for
   197 optimal performance tuning.  The corresponding usedir option -M allows
   198 "max" as an alias for "0".  WARNING: does not work on certain versions
   199 of Mac OS (with Poly/ML 5.1).
   200 
   201 * isatool tty runs Isabelle process with plain tty interaction;
   202 optional line editor may be specified via ISABELLE_LINE_EDITOR
   203 setting, the default settings attempt to locate "ledit" and "rlwrap".
   204 
   205 * isatool browser now works with Cygwin as well, using general
   206 "javapath" function defined in Isabelle process environment.
   207 
   208 * isabelle-process: non-ML sessions are run with "nice", to prevent
   209 Isabelle from flooding interactive front-ends (notably ProofGeneral /
   210 XEmacs).
   211 
   212 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   213 provides general wrapper for managing an Isabelle process in a robust
   214 fashion, with ``cooked'' output from stdin/stderr.
   215 
   216 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   217 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   218 
   219 
   220 
   221 New in Isabelle2007 (November 2007)
   222 -----------------------------------
   223 
   224 *** General ***
   225 
   226 * More uniform information about legacy features, notably a
   227 warning/error of "Legacy feature: ...", depending on the state of the
   228 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   229 legacy features will disappear eventually.
   230 
   231 * Theory syntax: the header format ``theory A = B + C:'' has been
   232 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   233 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   234 
   235 * Theory syntax: the old non-Isar theory file format has been
   236 discontinued altogether.  Note that ML proof scripts may still be used
   237 with Isar theories; migration is usually quite simple with the ML
   238 function use_legacy_bindings.  INCOMPATIBILITY.
   239 
   240 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   241 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   242 quotes.
   243 
   244 * Theory loader: be more serious about observing the static theory
   245 header specifications (including optional directories), but not the
   246 accidental file locations of previously successful loads.  The strict
   247 update policy of former update_thy is now already performed by
   248 use_thy, so the former has been removed; use_thys updates several
   249 theories simultaneously, just as 'imports' within a theory header
   250 specification, but without merging the results.  Potential
   251 INCOMPATIBILITY: may need to refine theory headers and commands
   252 ROOT.ML which depend on load order.
   253 
   254 * Theory loader: optional support for content-based file
   255 identification, instead of the traditional scheme of full physical
   256 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   257 (cf. the system manual).  The new scheme allows to work with
   258 non-finished theories in persistent session images, such that source
   259 files may be moved later on without requiring reloads.
   260 
   261 * Theory loader: old-style ML proof scripts being *attached* to a thy
   262 file (with the same base name as the theory) are considered a legacy
   263 feature, which will disappear eventually. Even now, the theory loader
   264 no longer maintains dependencies on such files.
   265 
   266 * Syntax: the scope for resolving ambiguities via type-inference is
   267 now limited to individual terms, instead of whole simultaneous
   268 specifications as before. This greatly reduces the complexity of the
   269 syntax module and improves flexibility by separating parsing and
   270 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
   271 'fixes' etc.) are required in rare situations.
   272 
   273 * Syntax: constants introduced by new-style packages ('definition',
   274 'abbreviation' etc.) are passed through the syntax module in
   275 ``authentic mode''. This means that associated mixfix annotations
   276 really stick to such constants, independently of potential name space
   277 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
   278 trees are represented slightly differently, may need to adapt syntax
   279 translations accordingly. Use CONST marker in 'translations' and
   280 @{const_syntax} antiquotation in 'parse_translation' etc.
   281 
   282 * Legacy goal package: reduced interface to the bare minimum required
   283 to keep existing proof scripts running.  Most other user-level
   284 functions are now part of the OldGoals structure, which is *not* open
   285 by default (consider isatool expandshort before open OldGoals).
   286 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   287 these tend to cause confusion about the actual goal (!) context being
   288 used here, which is not necessarily the same as the_context().
   289 
   290 * Command 'find_theorems': supports "*" wild-card in "name:"
   291 criterion; "with_dups" option.  Certain ProofGeneral versions might
   292 support a specific search form (see ProofGeneral/CHANGES).
   293 
   294 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   295 by default, which means that "prems" (and also "fixed variables") are
   296 suppressed from proof state output.  Note that the ProofGeneral
   297 settings mechanism allows to change and save options persistently, but
   298 older versions of Isabelle will fail to start up if a negative prems
   299 limit is imposed.
   300 
   301 * Local theory targets may be specified by non-nested blocks of
   302 ``context/locale/class ... begin'' followed by ``end''.  The body may
   303 contain definitions, theorems etc., including any derived mechanism
   304 that has been implemented on top of these primitives.  This concept
   305 generalizes the existing ``theorem (in ...)'' towards more versatility
   306 and scalability.
   307 
   308 * Proof General interface: proper undo of final 'end' command;
   309 discontinued Isabelle/classic mode (ML proof scripts).
   310 
   311 
   312 *** Document preparation ***
   313 
   314 * Added antiquotation @{theory name} which prints the given name,
   315 after checking that it refers to a valid ancestor theory in the
   316 current context.
   317 
   318 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   319 check the given source text as ML type/structure, printing verbatim.
   320 
   321 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   322 "c args == rhs" given in the current context.  (Any number of
   323 arguments may be given on the LHS.)
   324 
   325 
   326 *** Pure ***
   327 
   328 * The 'class' package offers a combination of axclass and locale to
   329 achieve Haskell-like type classes in Isabelle.  Definitions and
   330 theorems within a class context produce both relative results (with
   331 implicit parameters according to the locale context), and polymorphic
   332 constants with qualified polymorphism (according to the class
   333 context).  Within the body context of a 'class' target, a separate
   334 syntax layer ("user space type system") takes care of converting
   335 between global polymorphic consts and internal locale representation.
   336 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   337 "isatool doc classes" provides a tutorial.
   338 
   339 * Generic code generator framework allows to generate executable
   340 code for ML and Haskell (including Isabelle classes).  A short usage
   341 sketch:
   342 
   343     internal compilation:
   344         export_code <list of constants (term syntax)> in SML
   345     writing SML code to a file:
   346         export_code <list of constants (term syntax)> in SML <filename>
   347     writing OCaml code to a file:
   348         export_code <list of constants (term syntax)> in OCaml <filename>
   349     writing Haskell code to a bunch of files:
   350         export_code <list of constants (term syntax)> in Haskell <filename>
   351 
   352     evaluating closed propositions to True/False using code generation:
   353         method ``eval''
   354 
   355 Reasonable default setup of framework in HOL.
   356 
   357 Theorem attributs for selecting and transforming function equations theorems:
   358 
   359     [code fun]:        select a theorem as function equation for a specific constant
   360     [code fun del]:    deselect a theorem as function equation for a specific constant
   361     [code inline]:     select an equation theorem for unfolding (inlining) in place
   362     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   363 
   364 User-defined serializations (target in {SML, OCaml, Haskell}):
   365 
   366     code_const <and-list of constants (term syntax)>
   367       {(target) <and-list of const target syntax>}+
   368 
   369     code_type <and-list of type constructors>
   370       {(target) <and-list of type target syntax>}+
   371 
   372     code_instance <and-list of instances>
   373       {(target)}+
   374         where instance ::= <type constructor> :: <class>
   375 
   376     code_class <and_list of classes>
   377       {(target) <and-list of class target syntax>}+
   378         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   379 
   380 code_instance and code_class only are effective to target Haskell.
   381 
   382 For example usage see src/HOL/ex/Codegenerator.thy and
   383 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   384 generation from Isabelle/HOL theories is available via "isatool doc
   385 codegen".
   386 
   387 * Code generator: consts in 'consts_code' Isar commands are now
   388 referred to by usual term syntax (including optional type
   389 annotations).
   390 
   391 * Command 'no_translations' removes translation rules from theory
   392 syntax.
   393 
   394 * Overloaded definitions are now actually checked for acyclic
   395 dependencies.  The overloading scheme is slightly more general than
   396 that of Haskell98, although Isabelle does not demand an exact
   397 correspondence to type class and instance declarations.
   398 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   399 exotic versions of overloading -- at the discretion of the user!
   400 
   401 Polymorphic constants are represented via type arguments, i.e. the
   402 instantiation that matches an instance against the most general
   403 declaration given in the signature.  For example, with the declaration
   404 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   405 as c(nat).  Overloading is essentially simultaneous structural
   406 recursion over such type arguments.  Incomplete specification patterns
   407 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   408 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   409 Command 'print_theory' outputs the normalized system of recursive
   410 equations, see section "definitions".
   411 
   412 * Configuration options are maintained within the theory or proof
   413 context (with name and type bool/int/string), providing a very simple
   414 interface to a poor-man's version of general context data.  Tools may
   415 declare options in ML (e.g. using Attrib.config_int) and then refer to
   416 these values using Config.get etc.  Users may change options via an
   417 associated attribute of the same name.  This form of context
   418 declaration works particularly well with commands 'declare' or
   419 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   420 very easy to avoid global references, which would not observe Isar
   421 toplevel undo/redo and fail to work with multithreading.
   422 
   423 Various global ML references of Pure and HOL have been turned into
   424 configuration options:
   425 
   426   Unify.search_bound		unify_search_bound
   427   Unify.trace_bound		unify_trace_bound
   428   Unify.trace_simp		unify_trace_simp
   429   Unify.trace_types		unify_trace_types
   430   Simplifier.simp_depth_limit	simp_depth_limit
   431   Blast.depth_limit		blast_depth_limit
   432   DatatypeProp.dtK		datatype_distinctness_limit
   433   fast_arith_neq_limit  	fast_arith_neq_limit
   434   fast_arith_split_limit	fast_arith_split_limit
   435 
   436 * Named collections of theorems may be easily installed as context
   437 data using the functor NamedThmsFun (see also
   438 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   439 attributes; there is also a toplevel print command.  This facility is
   440 just a common case of general context data, which is the preferred way
   441 for anything more complex than just a list of facts in canonical
   442 order.
   443 
   444 * Isar: command 'declaration' augments a local theory by generic
   445 declaration functions written in ML.  This enables arbitrary content
   446 being added to the context, depending on a morphism that tells the
   447 difference of the original declaration context wrt. the application
   448 context encountered later on.
   449 
   450 * Isar: proper interfaces for simplification procedures.  Command
   451 'simproc_setup' declares named simprocs (with match patterns, and body
   452 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   453 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   454 
   455 * Isar: an extra pair of brackets around attribute declarations
   456 abbreviates a theorem reference involving an internal dummy fact,
   457 which will be ignored later --- only the effect of the attribute on
   458 the background context will persist.  This form of in-place
   459 declarations is particularly useful with commands like 'declare' and
   460 'using', for example ``have A using [[simproc a]] by simp''.
   461 
   462 * Isar: method "assumption" (and implicit closing of subproofs) now
   463 takes simple non-atomic goal assumptions into account: after applying
   464 an assumption as a rule the resulting subgoals are solved by atomic
   465 assumption steps.  This is particularly useful to finish 'obtain'
   466 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   467 without referring to the original premise "!!x. P x ==> thesis" in the
   468 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   469 more permissive.
   470 
   471 * Isar: implicit use of prems from the Isar proof context is
   472 considered a legacy feature.  Common applications like ``have A .''
   473 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   474 referencing facts explicitly here improves readability and
   475 maintainability of proof texts.
   476 
   477 * Isar: improper proof element 'guess' is like 'obtain', but derives
   478 the obtained context from the course of reasoning!  For example:
   479 
   480   assume "EX x y. A x & B y"   -- "any previous fact"
   481   then guess x and y by clarify
   482 
   483 This technique is potentially adventurous, depending on the facts and
   484 proof tools being involved here.
   485 
   486 * Isar: known facts from the proof context may be specified as literal
   487 propositions, using ASCII back-quote syntax.  This works wherever
   488 named facts used to be allowed so far, in proof commands, proof
   489 methods, attributes etc.  Literal facts are retrieved from the context
   490 according to unification of type and term parameters.  For example,
   491 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   492 theorems in the current context, then these are valid literal facts:
   493 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   494 
   495 There is also a proof method "fact" which does the same composition
   496 for explicit goal states, e.g. the following proof texts coincide with
   497 certain special cases of literal facts:
   498 
   499   have "A" by fact                 ==  note `A`
   500   have "A ==> B" by fact           ==  note `A ==> B`
   501   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   502   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   503 
   504 * Isar: ":" (colon) is no longer a symbolic identifier character in
   505 outer syntax.  Thus symbolic identifiers may be used without
   506 additional white space in declarations like this: ``assume *: A''.
   507 
   508 * Isar: 'print_facts' prints all local facts of the current context,
   509 both named and unnamed ones.
   510 
   511 * Isar: 'def' now admits simultaneous definitions, e.g.:
   512 
   513   def x == "t" and y == "u"
   514 
   515 * Isar: added command 'unfolding', which is structurally similar to
   516 'using', but affects both the goal state and facts by unfolding given
   517 rewrite rules.  Thus many occurrences of the 'unfold' method or
   518 'unfolded' attribute may be replaced by first-class proof text.
   519 
   520 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   521 and command 'unfolding' now all support object-level equalities
   522 (potentially conditional).  The underlying notion of rewrite rule is
   523 analogous to the 'rule_format' attribute, but *not* that of the
   524 Simplifier (which is usually more generous).
   525 
   526 * Isar: the new attribute [rotated n] (default n = 1) rotates the
   527 premises of a theorem by n. Useful in conjunction with drule.
   528 
   529 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   530 method expression within a sandbox consisting of the first N
   531 sub-goals, which need to exist.  For example, ``simp_all [3]''
   532 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   533 simplifies all new goals that emerge from applying rule foo to the
   534 originally first one.
   535 
   536 * Isar: schematic goals are no longer restricted to higher-order
   537 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   538 expected.
   539 
   540 * Isar: the conclusion of a long theorem statement is now either
   541 'shows' (a simultaneous conjunction, as before), or 'obtains'
   542 (essentially a disjunction of cases with local parameters and
   543 assumptions).  The latter allows to express general elimination rules
   544 adequately; in this notation common elimination rules look like this:
   545 
   546   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   547     assumes "EX x. P x"
   548     obtains x where "P x"
   549 
   550   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   551     assumes "A & B"
   552     obtains A and B
   553 
   554   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   555     assumes "A | B"
   556     obtains
   557       A
   558     | B
   559 
   560 The subsequent classical rules even refer to the formal "thesis"
   561 explicitly:
   562 
   563   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   564     obtains "~ thesis"
   565 
   566   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   567     obtains "thesis ==> something"
   568 
   569 The actual proof of an 'obtains' statement is analogous to that of the
   570 Isar proof element 'obtain', only that there may be several cases.
   571 Optional case names may be specified in parentheses; these will be
   572 available both in the present proof and as annotations in the
   573 resulting rule, for later use with the 'cases' method (cf. attribute
   574 case_names).
   575 
   576 * Isar: the assumptions of a long theorem statement are available as
   577 "assms" fact in the proof context.  This is more appropriate than the
   578 (historical) "prems", which refers to all assumptions of the current
   579 context, including those from the target locale, proof body etc.
   580 
   581 * Isar: 'print_statement' prints theorems from the current theory or
   582 proof context in long statement form, according to the syntax of a
   583 top-level lemma.
   584 
   585 * Isar: 'obtain' takes an optional case name for the local context
   586 introduction rule (default "that").
   587 
   588 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   589 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   590 to occur.
   591 
   592 * Pure: syntax "CONST name" produces a fully internalized constant
   593 according to the current context.  This is particularly useful for
   594 syntax translations that should refer to internal constant
   595 representations independently of name spaces.
   596 
   597 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   598 instead of "FOO ". This allows multiple binder declarations to coexist
   599 in the same context.  INCOMPATIBILITY.
   600 
   601 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   602 primitive that also works in a locale context (both for constants and
   603 fixed variables). Type declaration and internal syntactic representation
   604 of given constants retrieved from the context. Likewise, the
   605 'no_notation' command allows to remove given syntax annotations from the
   606 current context.
   607 
   608 * Isar/locales: new derived specification elements 'axiomatization',
   609 'definition', 'abbreviation', which support type-inference, admit
   610 object-level specifications (equality, equivalence).  See also the
   611 isar-ref manual.  Examples:
   612 
   613   axiomatization
   614     eq  (infix "===" 50) where
   615     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   616 
   617   definition "f x y = x + y + 1"
   618   definition g where "g x = f x x"
   619 
   620   abbreviation
   621     neq  (infix "=!=" 50) where
   622     "x =!= y == ~ (x === y)"
   623 
   624 These specifications may be also used in a locale context.  Then the
   625 constants being introduced depend on certain fixed parameters, and the
   626 constant name is qualified by the locale base name.  An internal
   627 abbreviation takes care for convenient input and output, making the
   628 parameters implicit and using the original short name.  See also
   629 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   630 entities from a monomorphic theory.
   631 
   632 Presently, abbreviations are only available 'in' a target locale, but
   633 not inherited by general import expressions.  Also note that
   634 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   635 'translations' in common applications.  The "no_abbrevs" print mode
   636 prevents folding of abbreviations in term output.
   637 
   638 Concrete syntax is attached to specified constants in internal form,
   639 independently of name spaces.  The parse tree representation is
   640 slightly different -- use 'notation' instead of raw 'syntax', and
   641 'translations' with explicit "CONST" markup to accommodate this.
   642 
   643 * Pure/Isar: unified syntax for new-style specification mechanisms
   644 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
   645 full type inference and dummy patterns ("_").  For example:
   646 
   647   definition "K x _ = x"
   648 
   649   inductive conj for A B
   650   where "A ==> B ==> conj A B"
   651 
   652 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   653 the current context.  Print mode "no_abbrevs" prevents inversion of
   654 abbreviations on output.
   655 
   656 * Isar/locales: improved parameter handling: use of locales "var" and
   657 "struct" no longer necessary; - parameter renamings are no longer
   658 required to be injective.  For example, this allows to define
   659 endomorphisms as locale endom = homom mult mult h.
   660 
   661 * Isar/locales: changed the way locales with predicates are defined.
   662 Instead of accumulating the specification, the imported expression is
   663 now an interpretation.  INCOMPATIBILITY: different normal form of
   664 locale expressions.  In particular, in interpretations of locales with
   665 predicates, goals repesenting already interpreted fragments are not
   666 removed automatically.  Use methods `intro_locales' and
   667 `unfold_locales'; see below.
   668 
   669 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   670 provide backward reasoning on locales predicates.  The methods are
   671 aware of interpretations and discharge corresponding goals.
   672 `intro_locales' is less aggressive then `unfold_locales' and does not
   673 unfold predicates to assumptions.
   674 
   675 * Isar/locales: the order in which locale fragments are accumulated
   676 has changed.  This enables to override declarations from fragments due
   677 to interpretations -- for example, unwanted simp rules.
   678 
   679 * Isar/locales: interpretation in theories and proof contexts has been
   680 extended.  One may now specify (and prove) equations, which are
   681 unfolded in interpreted theorems.  This is useful for replacing
   682 defined concepts (constants depending on locale parameters) by
   683 concepts already existing in the target context.  Example:
   684 
   685   interpretation partial_order ["op <= :: [int, int] => bool"]
   686     where "partial_order.less (op <=) (x::int) y = (x < y)"
   687 
   688 Typically, the constant `partial_order.less' is created by a
   689 definition specification element in the context of locale
   690 partial_order.
   691 
   692 * Method "induct": improved internal context management to support
   693 local fixes and defines on-the-fly. Thus explicit meta-level
   694 connectives !!  and ==> are rarely required anymore in inductive goals
   695 (using object-logic connectives for this purpose has been long
   696 obsolete anyway). Common proof patterns are explained in
   697 src/HOL/Induct/Common_Patterns.thy, see also
   698 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
   699 examples.
   700 
   701 * Method "induct": improved handling of simultaneous goals. Instead of
   702 introducing object-level conjunction, the statement is now split into
   703 several conclusions, while the corresponding symbolic cases are nested
   704 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
   705 see src/HOL/Induct/Common_Patterns.thy, for example.
   706 
   707 * Method "induct": mutual induction rules are now specified as a list
   708 of rule sharing the same induction cases. HOL packages usually provide
   709 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
   710 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
   711 mutual induction rules differently, i.e. like this:
   712 
   713   (induct rule: foo_bar.inducts)
   714   (induct set: foo bar)
   715   (induct pred: foo bar)
   716   (induct type: foo bar)
   717 
   718 The ML function ProjectRule.projections turns old-style rules into the
   719 new format.
   720 
   721 * Method "coinduct": dual of induction, see
   722 src/HOL/Library/Coinductive_List.thy for various examples.
   723 
   724 * Method "cases", "induct", "coinduct": the ``(open)'' option is
   725 considered a legacy feature.
   726 
   727 * Attribute "symmetric" produces result with standardized schematic
   728 variables (index 0).  Potential INCOMPATIBILITY.
   729 
   730 * Simplifier: by default the simplifier trace only shows top level
   731 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   732 default. Thus there is less danger of being flooded by the trace. The
   733 trace indicates where parts have been suppressed.
   734   
   735 * Provers/classical: removed obsolete classical version of elim_format
   736 attribute; classical elim/dest rules are now treated uniformly when
   737 manipulating the claset.
   738 
   739 * Provers/classical: stricter checks to ensure that supplied intro,
   740 dest and elim rules are well-formed; dest and elim rules must have at
   741 least one premise.
   742 
   743 * Provers/classical: attributes dest/elim/intro take an optional
   744 weight argument for the rule (just as the Pure versions).  Weights are
   745 ignored by automated tools, but determine the search order of single
   746 rule steps.
   747 
   748 * Syntax: input syntax now supports dummy variable binding "%_. b",
   749 where the body does not mention the bound variable.  Note that dummy
   750 patterns implicitly depend on their context of bounds, which makes
   751 "{_. _}" match any set comprehension as expected.  Potential
   752 INCOMPATIBILITY -- parse translations need to cope with syntactic
   753 constant "_idtdummy" in the binding position.
   754 
   755 * Syntax: removed obsolete syntactic constant "_K" and its associated
   756 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   757 for example "A -> B" => "Pi A (%_. B)".
   758 
   759 * Pure: 'class_deps' command visualizes the subclass relation, using
   760 the graph browser tool.
   761 
   762 * Pure: 'print_theory' now suppresses certain internal declarations by
   763 default; use '!' option for full details.
   764 
   765 
   766 *** HOL ***
   767 
   768 * Method "metis" proves goals by applying the Metis general-purpose
   769 resolution prover (see also http://gilith.com/software/metis/).
   770 Examples are in the directory MetisExamples.  WARNING: the
   771 Isabelle/HOL-Metis integration does not yet work properly with
   772 multi-threading.
   773   
   774 * Command 'sledgehammer' invokes external automatic theorem provers as
   775 background processes.  It generates calls to the "metis" method if
   776 successful. These can be pasted into the proof.  Users do not have to
   777 wait for the automatic provers to return.  WARNING: does not really
   778 work with multi-threading.
   779 
   780 * New "auto_quickcheck" feature tests outermost goal statements for
   781 potential counter-examples.  Controlled by ML references
   782 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
   783 5000 milliseconds).  Fails silently if statements is outside of
   784 executable fragment, or any other codgenerator problem occurs.
   785 
   786 * New constant "undefined" with axiom "undefined x = undefined".
   787 
   788 * Added class "HOL.eq", allowing for code generation with polymorphic
   789 equality.
   790 
   791 * Some renaming of class constants due to canonical name prefixing in
   792 the new 'class' package:
   793 
   794     HOL.abs ~> HOL.abs_class.abs
   795     HOL.divide ~> HOL.divide_class.divide
   796     0 ~> HOL.zero_class.zero
   797     1 ~> HOL.one_class.one
   798     op + ~> HOL.plus_class.plus
   799     op - ~> HOL.minus_class.minus
   800     uminus ~> HOL.minus_class.uminus
   801     op * ~> HOL.times_class.times
   802     op < ~> HOL.ord_class.less
   803     op <= > HOL.ord_class.less_eq
   804     Nat.power ~> Power.power_class.power
   805     Nat.size ~> Nat.size_class.size
   806     Numeral.number_of ~> Numeral.number_class.number_of
   807     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
   808     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
   809     Orderings.min ~> Orderings.ord_class.min
   810     Orderings.max ~> Orderings.ord_class.max
   811     Divides.op div ~> Divides.div_class.div
   812     Divides.op mod ~> Divides.div_class.mod
   813     Divides.op dvd ~> Divides.div_class.dvd
   814 
   815 INCOMPATIBILITY.  Adaptions may be required in the following cases:
   816 
   817 a) User-defined constants using any of the names "plus", "minus",
   818 "times", "less" or "less_eq". The standard syntax translations for
   819 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
   820 names.
   821 
   822 b) Variables named "plus", "minus", "times", "less", "less_eq"
   823 INCOMPATIBILITY: use more specific names.
   824 
   825 c) Permutative equations (e.g. "a + b = b + a")
   826 Since the change of names also changes the order of terms, permutative
   827 rewrite rules may get applied in a different order. Experience shows
   828 that this is rarely the case (only two adaptions in the whole Isabelle
   829 distribution).  INCOMPATIBILITY: rewrite proofs
   830 
   831 d) ML code directly refering to constant names
   832 This in general only affects hand-written proof tactics, simprocs and
   833 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
   834 Consider using @{const_name} antiquotation.
   835 
   836 * New class "default" with associated constant "default".
   837 
   838 * Function "sgn" is now overloaded and available on int, real, complex
   839 (and other numeric types), using class "sgn".  Two possible defs of
   840 sgn are given as equational assumptions in the classes sgn_if and
   841 sgn_div_norm; ordered_idom now also inherits from sgn_if.
   842 INCOMPATIBILITY.
   843 
   844 * Locale "partial_order" now unified with class "order" (cf. theory
   845 Orderings), added parameter "less".  INCOMPATIBILITY.
   846 
   847 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
   848 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
   849 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
   850 
   851 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
   852 changed order of proof goals in instance proofs.
   853 
   854 * The transitivity reasoner for partial and linear orders is set up
   855 for classes "order" and "linorder".  Instances of the reasoner are available
   856 in all contexts importing or interpreting the corresponding locales.
   857 Method "order" invokes the reasoner separately; the reasoner
   858 is also integrated with the Simplifier as a solver.  Diagnostic
   859 command 'print_orders' shows the available instances of the reasoner
   860 in the current context.
   861 
   862 * Localized monotonicity predicate in theory "Orderings"; integrated
   863 lemmas max_of_mono and min_of_mono with this predicate.
   864 INCOMPATIBILITY.
   865 
   866 * Formulation of theorem "dense" changed slightly due to integration
   867 with new class dense_linear_order.
   868 
   869 * Uniform lattice theory development in HOL.
   870 
   871     constants "meet" and "join" now named "inf" and "sup"
   872     constant "Meet" now named "Inf"
   873 
   874     classes "meet_semilorder" and "join_semilorder" now named
   875       "lower_semilattice" and "upper_semilattice"
   876     class "lorder" now named "lattice"
   877     class "comp_lat" now named "complete_lattice"
   878 
   879     Instantiation of lattice classes allows explicit definitions
   880     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
   881 
   882   INCOMPATIBILITY.  Theorem renames:
   883 
   884     meet_left_le            ~> inf_le1
   885     meet_right_le           ~> inf_le2
   886     join_left_le            ~> sup_ge1
   887     join_right_le           ~> sup_ge2
   888     meet_join_le            ~> inf_sup_ord
   889     le_meetI                ~> le_infI
   890     join_leI                ~> le_supI
   891     le_meet                 ~> le_inf_iff
   892     le_join                 ~> ge_sup_conv
   893     meet_idempotent         ~> inf_idem
   894     join_idempotent         ~> sup_idem
   895     meet_comm               ~> inf_commute
   896     join_comm               ~> sup_commute
   897     meet_leI1               ~> le_infI1
   898     meet_leI2               ~> le_infI2
   899     le_joinI1               ~> le_supI1
   900     le_joinI2               ~> le_supI2
   901     meet_assoc              ~> inf_assoc
   902     join_assoc              ~> sup_assoc
   903     meet_left_comm          ~> inf_left_commute
   904     meet_left_idempotent    ~> inf_left_idem
   905     join_left_comm          ~> sup_left_commute
   906     join_left_idempotent    ~> sup_left_idem
   907     meet_aci                ~> inf_aci
   908     join_aci                ~> sup_aci
   909     le_def_meet             ~> le_iff_inf
   910     le_def_join             ~> le_iff_sup
   911     join_absorp2            ~> sup_absorb2
   912     join_absorp1            ~> sup_absorb1
   913     meet_absorp1            ~> inf_absorb1
   914     meet_absorp2            ~> inf_absorb2
   915     meet_join_absorp        ~> inf_sup_absorb
   916     join_meet_absorp        ~> sup_inf_absorb
   917     distrib_join_le         ~> distrib_sup_le
   918     distrib_meet_le         ~> distrib_inf_le
   919 
   920     add_meet_distrib_left   ~> add_inf_distrib_left
   921     add_join_distrib_left   ~> add_sup_distrib_left
   922     is_join_neg_meet        ~> is_join_neg_inf
   923     is_meet_neg_join        ~> is_meet_neg_sup
   924     add_meet_distrib_right  ~> add_inf_distrib_right
   925     add_join_distrib_right  ~> add_sup_distrib_right
   926     add_meet_join_distribs  ~> add_sup_inf_distribs
   927     join_eq_neg_meet        ~> sup_eq_neg_inf
   928     meet_eq_neg_join        ~> inf_eq_neg_sup
   929     add_eq_meet_join        ~> add_eq_inf_sup
   930     meet_0_imp_0            ~> inf_0_imp_0
   931     join_0_imp_0            ~> sup_0_imp_0
   932     meet_0_eq_0             ~> inf_0_eq_0
   933     join_0_eq_0             ~> sup_0_eq_0
   934     neg_meet_eq_join        ~> neg_inf_eq_sup
   935     neg_join_eq_meet        ~> neg_sup_eq_inf
   936     join_eq_if              ~> sup_eq_if
   937 
   938     mono_meet               ~> mono_inf
   939     mono_join               ~> mono_sup
   940     meet_bool_eq            ~> inf_bool_eq
   941     join_bool_eq            ~> sup_bool_eq
   942     meet_fun_eq             ~> inf_fun_eq
   943     join_fun_eq             ~> sup_fun_eq
   944     meet_set_eq             ~> inf_set_eq
   945     join_set_eq             ~> sup_set_eq
   946     meet1_iff               ~> inf1_iff
   947     meet2_iff               ~> inf2_iff
   948     meet1I                  ~> inf1I
   949     meet2I                  ~> inf2I
   950     meet1D1                 ~> inf1D1
   951     meet2D1                 ~> inf2D1
   952     meet1D2                 ~> inf1D2
   953     meet2D2                 ~> inf2D2
   954     meet1E                  ~> inf1E
   955     meet2E                  ~> inf2E
   956     join1_iff               ~> sup1_iff
   957     join2_iff               ~> sup2_iff
   958     join1I1                 ~> sup1I1
   959     join2I1                 ~> sup2I1
   960     join1I1                 ~> sup1I1
   961     join2I2                 ~> sup1I2
   962     join1CI                 ~> sup1CI
   963     join2CI                 ~> sup2CI
   964     join1E                  ~> sup1E
   965     join2E                  ~> sup2E
   966 
   967     is_meet_Meet            ~> is_meet_Inf
   968     Meet_bool_def           ~> Inf_bool_def
   969     Meet_fun_def            ~> Inf_fun_def
   970     Meet_greatest           ~> Inf_greatest
   971     Meet_lower              ~> Inf_lower
   972     Meet_set_def            ~> Inf_set_def
   973 
   974     Sup_def                 ~> Sup_Inf
   975     Sup_bool_eq             ~> Sup_bool_def
   976     Sup_fun_eq              ~> Sup_fun_def
   977     Sup_set_eq              ~> Sup_set_def
   978 
   979     listsp_meetI            ~> listsp_infI
   980     listsp_meet_eq          ~> listsp_inf_eq
   981 
   982     meet_min                ~> inf_min
   983     join_max                ~> sup_max
   984 
   985 * Added syntactic class "size"; overloaded constant "size" now has
   986 type "'a::size ==> bool"
   987 
   988 * Internal reorganisation of `size' of datatypes: size theorems
   989 "foo.size" are no longer subsumed by "foo.simps" (but are still
   990 simplification rules by default!); theorems "prod.size" now named
   991 "*.size".
   992 
   993 * Class "div" now inherits from class "times" rather than "type".
   994 INCOMPATIBILITY.
   995 
   996 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
   997 Linorder etc.  have disappeared; operations defined in terms of
   998 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
   999 
  1000 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1001 
  1002 * HOL-Word: New extensive library and type for generic, fixed size
  1003 machine words, with arithemtic, bit-wise, shifting and rotating
  1004 operations, reflection into int, nat, and bool lists, automation for
  1005 linear arithmetic (by automatic reflection into nat or int), including
  1006 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1007 arithmetic type classes, supporting automatic simplification of
  1008 numerals on all operations.
  1009 
  1010 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1011 
  1012 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1013 
  1014 * Code generator library theories:
  1015   - Code_Integer represents HOL integers by big integer literals in target
  1016     languages.
  1017   - Code_Char represents HOL characters by character literals in target
  1018     languages.
  1019   - Code_Char_chr like Code_Char, but also offers treatment of character
  1020     codes; includes Code_Integer.
  1021   - Executable_Set allows to generate code for finite sets using lists.
  1022   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1023     denominator).
  1024   - Executable_Real implements a subset of real numbers, namly those
  1025     representable by rational numbers.
  1026   - Efficient_Nat implements natural numbers by integers, which in general will
  1027     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1028     includes Code_Integer.
  1029   - Code_Index provides an additional datatype index which is mapped to
  1030     target-language built-in integers.
  1031   - Code_Message provides an additional datatype message_string} which is isomorphic to
  1032     strings; messages are mapped to target-language strings.
  1033 
  1034 * New package for inductive predicates
  1035 
  1036   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1037 
  1038     inductive
  1039       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1040       for z_1 :: U_1 and ... and z_n :: U_m
  1041     where
  1042       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1043     | ...
  1044 
  1045   with full support for type-inference, rather than
  1046 
  1047     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1048 
  1049     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1050     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1051 
  1052     inductive "s z_1 ... z_m"
  1053     intros
  1054       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1055       ...
  1056 
  1057   For backward compatibility, there is a wrapper allowing inductive
  1058   sets to be defined with the new package via
  1059 
  1060     inductive_set
  1061       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1062       for z_1 :: U_1 and ... and z_n :: U_m
  1063     where
  1064       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1065     | ...
  1066 
  1067   or
  1068 
  1069     inductive_set
  1070       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1071       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1072       for z_1 :: U_1 and ... and z_n :: U_m
  1073     where
  1074       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1075     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1076     | ...
  1077 
  1078   if the additional syntax "p ..." is required.
  1079 
  1080   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1081   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1082 
  1083   INCOMPATIBILITIES:
  1084 
  1085   - Since declaration and definition of inductive sets or predicates
  1086     is no longer separated, abbreviations involving the newly
  1087     introduced sets or predicates must be specified together with the
  1088     introduction rules after the 'where' keyword (see above), rather
  1089     than before the actual inductive definition.
  1090 
  1091   - The variables in induction and elimination rules are now
  1092     quantified in the order of their occurrence in the introduction
  1093     rules, rather than in alphabetical order. Since this may break
  1094     some proofs, these proofs either have to be repaired, e.g. by
  1095     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1096     statements of the form
  1097 
  1098       case (rule_i a_i_1 ... a_i_{k_i})
  1099 
  1100     or the old order of quantification has to be restored by explicitly adding
  1101     meta-level quantifiers in the introduction rules, i.e.
  1102 
  1103       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1104 
  1105   - The format of the elimination rules is now
  1106 
  1107       p z_1 ... z_m x_1 ... x_n ==>
  1108         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1109         ==> ... ==> P
  1110 
  1111     for predicates and
  1112 
  1113       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1114         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1115         ==> ... ==> P
  1116 
  1117     for sets rather than
  1118 
  1119       x : s z_1 ... z_m ==>
  1120         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1121         ==> ... ==> P
  1122 
  1123     This may require terms in goals to be expanded to n-tuples
  1124     (e.g. using case_tac or simplification with the split_paired_all
  1125     rule) before the above elimination rule is applicable.
  1126 
  1127   - The elimination or case analysis rules for (mutually) inductive
  1128     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1129     list of rules "p_1_..._p_k.elims" is no longer available.
  1130 
  1131 * New package "function"/"fun" for general recursive functions,
  1132 supporting mutual and nested recursion, definitions in local contexts,
  1133 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1134 for small examples, and the separate tutorial on the function
  1135 package. The old recdef "package" is still available as before, but
  1136 users are encouraged to use the new package.
  1137 
  1138 * Method "lexicographic_order" automatically synthesizes termination
  1139 relations as lexicographic combinations of size measures. 
  1140 
  1141 * Case-expressions allow arbitrary constructor-patterns (including
  1142 "_") and take their order into account, like in functional
  1143 programming.  Internally, this is translated into nested
  1144 case-expressions; missing cases are added and mapped to the predefined
  1145 constant "undefined". In complicated cases printing may no longer show
  1146 the original input but the internal form. Lambda-abstractions allow
  1147 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1148 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1149 variable.
  1150 
  1151 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1152 is an abbreviation for "of_nat :: nat => int". The simplification
  1153 rules for "of_nat" have been changed to work like "int" did
  1154 previously.  Potential INCOMPATIBILITY:
  1155   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1156   - of_nat_diff and of_nat_mult are no longer default simp rules
  1157 
  1158 * Method "algebra" solves polynomial equations over (semi)rings using
  1159 Groebner bases. The (semi)ring structure is defined by locales and the
  1160 tool setup depends on that generic context. Installing the method for
  1161 a specific type involves instantiating the locale and possibly adding
  1162 declarations for computation on the coefficients.  The method is
  1163 already instantiated for natural numbers and for the axiomatic class
  1164 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1165 CALCULEMUS 2007 for the general principles underlying this
  1166 architecture of context-aware proof-tools.
  1167 
  1168 * Method "ferrack" implements quantifier elimination over
  1169 special-purpose dense linear orders using locales (analogous to
  1170 "algebra"). The method is already installed for class
  1171 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1172 rat, etc.
  1173 
  1174 * Former constant "List.op @" now named "List.append".  Use ML
  1175 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1176 circumvent possible incompatibilities when working on ML level.
  1177 
  1178 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1179 
  1180 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1181 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1182 
  1183 * New syntax for Haskell-like list comprehension (input only), eg.
  1184 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1185 
  1186 * The special syntax for function "filter" has changed from [x :
  1187 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1188 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1189 
  1190 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1191 defined on nat only, as an abbreviation for [a..<Suc b]
  1192 INCOMPATIBILITY.
  1193 
  1194 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1195 
  1196 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1197 
  1198 * New lemma collection field_simps (an extension of ring_simps) for
  1199 manipulating (in)equations involving division. Multiplies with all
  1200 denominators that can be proved to be non-zero (in equations) or
  1201 positive/negative (in inequations).
  1202 
  1203 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1204 have been improved and renamed to ring_simps, group_simps and
  1205 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1206 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1207 
  1208 * Theory Library/Commutative_Ring: switched from recdef to function
  1209 package; constants add, mul, pow now curried.  Infix syntax for
  1210 algebraic operations.
  1211 
  1212 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1213 INCOMPATIBILITY.
  1214 
  1215 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1216 INCOMPATIBILITY.
  1217 
  1218 * HOL/records: generalised field-update to take a function on the
  1219 field rather than the new value: r(|A := x|) is translated to A_update
  1220 (K x) r The K-combinator that is internally used is called K_record.
  1221 INCOMPATIBILITY: Usage of the plain update functions has to be
  1222 adapted.
  1223  
  1224 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1225 * x = 0, which are required for a semiring.  Richer structures do not
  1226 inherit from semiring_0 anymore, because this property is a theorem
  1227 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1228 there is more to prove, but this is mostly trivial.
  1229 
  1230 * Class "recpower" is generalized to arbitrary monoids, not just
  1231 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1232 commutativity or semiring properties additionally.
  1233 
  1234 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1235 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1236 better use 'abbreviation'.
  1237 
  1238 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1239 
  1240 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1241 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1242 significant changes for setting up numeral syntax for types:
  1243   - New constants Numeral.pred and Numeral.succ instead
  1244       of former Numeral.bin_pred and Numeral.bin_succ.
  1245   - Use integer operations instead of bin_add, bin_mult and so on.
  1246   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1247   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1248 
  1249 See src/HOL/Integ/IntArith.thy for an example setup.
  1250 
  1251 * Command 'normal_form' computes the normal form of a term that may
  1252 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1253 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1254 heavy-duty computations because the functions are compiled to ML
  1255 first.  Correspondingly, a method "normalization" is provided.  See
  1256 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1257 
  1258 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1259 25 like -->); output depends on the "iff" print_mode, the default is
  1260 "A = B" (with priority 50).
  1261 
  1262 * Relations less (<) and less_eq (<=) are also available on type bool.
  1263 Modified syntax to disallow nesting without explicit parentheses,
  1264 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1265 INCOMPATIBILITY.
  1266 
  1267 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1268 
  1269 * Relation composition operator "op O" now has precedence 75 and binds
  1270 stronger than union and intersection. INCOMPATIBILITY.
  1271 
  1272 * The old set interval syntax "{m..n(}" (and relatives) has been
  1273 removed.  Use "{m..<n}" (and relatives) instead.
  1274 
  1275 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1276 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1277 ``declare [[simproc del: neq]]''.
  1278 
  1279 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1280 True/False.
  1281 
  1282 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1283 
  1284 * Theorem setsum_mult renamed to setsum_right_distrib.
  1285 
  1286 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1287 ``rule'' method.
  1288 
  1289 * Reimplemented methods "sat" and "satx", with several improvements:
  1290 goals no longer need to be stated as "<prems> ==> False", equivalences
  1291 (i.e. "=" on type bool) are handled, variable names of the form
  1292 "lit_<n>" are no longer reserved, significant speedup.
  1293 
  1294 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1295 zChaff is still supported as well.
  1296 
  1297 * 'inductive' and 'datatype': provide projections of mutual rules,
  1298 bundled as foo_bar.inducts;
  1299 
  1300 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1301 Library.
  1302 
  1303 * Library: moved theory Accessible_Part to main HOL.
  1304 
  1305 * Library: added theory Coinductive_List of potentially infinite lists
  1306 as greatest fixed-point.
  1307 
  1308 * Library: added theory AssocList which implements (finite) maps as
  1309 association lists.
  1310 
  1311 * Method "evaluation" solves goals (i.e. a boolean expression)
  1312 efficiently by compiling it to ML.  The goal is "proved" (via an
  1313 oracle) if it evaluates to True.
  1314 
  1315 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1316 also when invoked by the simplifier.  This results in the Simplifier
  1317 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1318 Configuration option fast_arith_split_limit=0 recovers the old
  1319 behavior.
  1320 
  1321 * Support for hex (0x20) and binary (0b1001) numerals.
  1322 
  1323 * New method: reify eqs (t), where eqs are equations for an
  1324 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1325 parameter, computes a term s::'b and a list xs::'a list and proves the
  1326 theorem I xs s = t. This is also known as reification or quoting. The
  1327 resulting theorem is applied to the subgoal to substitute t with I xs
  1328 s.  If t is omitted, the subgoal itself is reified.
  1329 
  1330 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1331 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1332 where f is supposed to be a computable function (in the sense of code
  1333 generattion). The method uses reify to compute s and xs as above then
  1334 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1335 r and finally gets the theorem t = r, which is again applied to the
  1336 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1337 
  1338 * Reflection: Automatic reification now handels binding, an example is
  1339 available in src/HOL/ex/ReflectionEx.thy
  1340 
  1341 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1342 command 'statespace' that is similar to 'record', but introduces an
  1343 abstract specification based on the locale infrastructure instead of
  1344 HOL types.  This leads to extra flexibility in composing state spaces,
  1345 in particular multiple inheritance and renaming of components.
  1346 
  1347 
  1348 *** HOL-Complex ***
  1349 
  1350 * Hyperreal: Functions root and sqrt are now defined on negative real
  1351 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1352 Nonnegativity side conditions have been removed from many lemmas, so
  1353 that more subgoals may now be solved by simplification; potential
  1354 INCOMPATIBILITY.
  1355 
  1356 * Real: new type classes formalize real normed vector spaces and
  1357 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1358 and norm :: 'a => real.
  1359 
  1360 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1361 reals into other types. The overloaded constant Reals :: 'a set is now
  1362 defined as range of_real; potential INCOMPATIBILITY.
  1363 
  1364 * Real: proper support for ML code generation, including 'quickcheck'.
  1365 Reals are implemented as arbitrary precision rationals.
  1366 
  1367 * Hyperreal: Several constants that previously worked only for the
  1368 reals have been generalized, so they now work over arbitrary vector
  1369 spaces. Type annotations may need to be added in some cases; potential
  1370 INCOMPATIBILITY.
  1371 
  1372   Infinitesimal  :: ('a::real_normed_vector) star set
  1373   HFinite        :: ('a::real_normed_vector) star set
  1374   HInfinite      :: ('a::real_normed_vector) star set
  1375   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1376   monad          :: ('a::real_normed_vector) star => 'a star set
  1377   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1378   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1379   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1380   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1381   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1382   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1383   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1384   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1385   sgn            :: 'a::real_normed_vector => 'a
  1386   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1387 
  1388 * Complex: Some complex-specific constants are now abbreviations for
  1389 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1390 hnorm.  Other constants have been entirely removed in favor of the
  1391 polymorphic versions (INCOMPATIBILITY):
  1392 
  1393   approx        <-- capprox
  1394   HFinite       <-- CFinite
  1395   HInfinite     <-- CInfinite
  1396   Infinitesimal <-- CInfinitesimal
  1397   monad         <-- cmonad
  1398   galaxy        <-- cgalaxy
  1399   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1400   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1401   (ns)deriv     <-- (ns)cderiv
  1402 
  1403 
  1404 *** HOL-Algebra ***
  1405 
  1406 * Formalisation of ideals and the quotient construction over rings.
  1407 
  1408 * Order and lattice theory no longer based on records.
  1409 INCOMPATIBILITY.
  1410 
  1411 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1412 greatest_closed.  INCOMPATIBILITY.
  1413 
  1414 * Method algebra is now set up via an attribute.  For examples see
  1415 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1416 of algebraic structures.
  1417 
  1418 * Renamed theory CRing to Ring.
  1419 
  1420 
  1421 *** HOL-Nominal ***
  1422 
  1423 * Substantial, yet incomplete support for nominal datatypes (binding
  1424 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  1425 src/HOL/Nominal/Examples.  Prospective users should consult
  1426 http://isabelle.in.tum.de/nominal/
  1427 
  1428 
  1429 *** ML ***
  1430 
  1431 * ML basics: just one true type int, which coincides with IntInf.int
  1432 (even on SML/NJ).
  1433 
  1434 * ML within Isar: antiquotations allow to embed statically-checked
  1435 formal entities in the source, referring to the context available at
  1436 compile-time.  For example:
  1437 
  1438 ML {* @{sort "{zero,one}"} *}
  1439 ML {* @{typ "'a => 'b"} *}
  1440 ML {* @{term "%x. x"} *}
  1441 ML {* @{prop "x == y"} *}
  1442 ML {* @{ctyp "'a => 'b"} *}
  1443 ML {* @{cterm "%x. x"} *}
  1444 ML {* @{cprop "x == y"} *}
  1445 ML {* @{thm asm_rl} *}
  1446 ML {* @{thms asm_rl} *}
  1447 ML {* @{type_name c} *}
  1448 ML {* @{type_syntax c} *}
  1449 ML {* @{const_name c} *}
  1450 ML {* @{const_syntax c} *}
  1451 ML {* @{context} *}
  1452 ML {* @{theory} *}
  1453 ML {* @{theory Pure} *}
  1454 ML {* @{theory_ref} *}
  1455 ML {* @{theory_ref Pure} *}
  1456 ML {* @{simpset} *}
  1457 ML {* @{claset} *}
  1458 ML {* @{clasimpset} *}
  1459 
  1460 The same works for sources being ``used'' within an Isar context.
  1461 
  1462 * ML in Isar: improved error reporting; extra verbosity with
  1463 ML_Context.trace enabled.
  1464 
  1465 * Pure/General/table.ML: the join operations now works via exceptions
  1466 DUP/SAME instead of type option. This is simpler in simple cases, and
  1467 admits slightly more efficient complex applications.
  1468 
  1469 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1470 use Context.generic instead of just theory.
  1471 
  1472 * Pure: datatype Context.generic joins theory/Proof.context and
  1473 provides some facilities for code that works in either kind of
  1474 context, notably GenericDataFun for uniform theory and proof data.
  1475 
  1476 * Pure: simplified internal attribute type, which is now always
  1477 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  1478 local (Proof.context) attributes have been discontinued, while
  1479 minimizing code duplication. Thm.rule_attribute and
  1480 Thm.declaration_attribute build canonical attributes; see also structure
  1481 Context for further operations on Context.generic, notably
  1482 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  1483 declarations and definitions.
  1484 
  1485 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1486 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1487 init only required for impure data. INCOMPATIBILITY: empty really need
  1488 to be empty (no dependencies on theory content!)
  1489 
  1490 * Pure/kernel: consts certification ignores sort constraints given in
  1491 signature declarations. (This information is not relevant to the
  1492 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  1493 potential INCOMPATIBILITY.
  1494 
  1495 * Pure: axiomatic type classes are now purely definitional, with
  1496 explicit proofs of class axioms and super class relations performed
  1497 internally. See Pure/axclass.ML for the main internal interfaces --
  1498 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1499 AxClass.axiomatize_class/classrel/arity supersede
  1500 Sign.add_classes/classrel/arities.
  1501 
  1502 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1503 global/local versions on theory vs. Proof.context have been
  1504 discontinued; Attrib.syntax and Method.syntax have been adapted
  1505 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1506 attributes, methods, etc.
  1507 
  1508 * Pure: several functions of signature "... -> theory -> theory * ..."
  1509 have been reoriented to "... -> theory -> ... * theory" in order to
  1510 allow natural usage in combination with the ||>, ||>>, |-> and
  1511 fold_map combinators.
  1512 
  1513 * Pure: official theorem names (closed derivations) and additional
  1514 comments (tags) are now strictly separate.  Name hints -- which are
  1515 maintained as tags -- may be attached any time without affecting the
  1516 derivation.
  1517 
  1518 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1519 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1520 achieve the old behaviour.
  1521 
  1522 * Pure: the "Goal" constant is now called "prop", supporting a
  1523 slightly more general idea of ``protecting'' meta-level rule
  1524 statements.
  1525 
  1526 * Pure: Logic.(un)varify only works in a global context, which is now
  1527 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1528 Logic.legacy_(un)varify as temporary workaround.
  1529 
  1530 * Pure: structure Name provides scalable operations for generating
  1531 internal variable names, notably Name.variants etc.  This replaces
  1532 some popular functions from term.ML:
  1533 
  1534   Term.variant		->  Name.variant
  1535   Term.variantlist	->  Name.variant_list
  1536   Term.invent_names	->  Name.invent_list
  1537 
  1538 Note that low-level renaming rarely occurs in new code -- operations
  1539 from structure Variable are used instead (see below).
  1540 
  1541 * Pure: structure Variable provides fundamental operations for proper
  1542 treatment of fixed/schematic variables in a context.  For example,
  1543 Variable.import introduces fixes for schematics of given facts and
  1544 Variable.export reverses the effect (up to renaming) -- this replaces
  1545 various freeze_thaw operations.
  1546 
  1547 * Pure: structure Goal provides simple interfaces for
  1548 init/conclude/finish and tactical prove operations (replacing former
  1549 Tactic.prove).  Goal.prove is the canonical way to prove results
  1550 within a given context; Goal.prove_global is a degraded version for
  1551 theory level goals, including a global Drule.standard.  Note that
  1552 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1553 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1554 in a locale context).
  1555 
  1556 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  1557 and type checking (Syntax.check_term etc.), with common combinations
  1558 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  1559 which are considered legacy and await removal.
  1560 
  1561 * Pure/Syntax: generic interfaces for type unchecking
  1562 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  1563 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  1564 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  1565 available for convenience, but refer to the very same operations using
  1566 a mere theory instead of a full context.
  1567 
  1568 * Isar: simplified treatment of user-level errors, using exception
  1569 ERROR of string uniformly.  Function error now merely raises ERROR,
  1570 without any side effect on output channels.  The Isar toplevel takes
  1571 care of proper display of ERROR exceptions.  ML code may use plain
  1572 handle/can/try; cat_error may be used to concatenate errors like this:
  1573 
  1574   ... handle ERROR msg => cat_error msg "..."
  1575 
  1576 Toplevel ML code (run directly or through the Isar toplevel) may be
  1577 embedded into the Isar toplevel with exception display/debug like
  1578 this:
  1579 
  1580   Isar.toplevel (fn () => ...)
  1581 
  1582 INCOMPATIBILITY, removed special transform_error facilities, removed
  1583 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1584 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1585 -- use plain ERROR instead.
  1586 
  1587 * Isar: theory setup now has type (theory -> theory), instead of a
  1588 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1589 
  1590 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  1591 ProofContext.debug/verbose flags.
  1592 
  1593 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1594 theory before entering a proof state.  Transactions now always see a
  1595 quasi-functional intermediate checkpoint, both in interactive and
  1596 batch mode.
  1597 
  1598 * Isar: simplified interfaces for outer syntax.  Renamed
  1599 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  1600 OuterSyntax.add_parsers -- this functionality is now included in
  1601 OuterSyntax.command etc.  INCOMPATIBILITY.
  1602 
  1603 * Simplifier: the simpset of a running simplification process now
  1604 contains a proof context (cf. Simplifier.the_context), which is the
  1605 very context that the initial simpset has been retrieved from (by
  1606 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1607 (solver, looper etc.) may depend on arbitrary proof data.
  1608 
  1609 * Simplifier.inherit_context inherits the proof context (plus the
  1610 local bounds) of the current simplification process; any simproc
  1611 etc. that calls the Simplifier recursively should do this!  Removed
  1612 former Simplifier.inherit_bounds, which is already included here --
  1613 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1614 specify an explicit context using Simplifier.context/theory_context.
  1615 
  1616 * Simplifier/Classical Reasoner: more abstract interfaces
  1617 change_simpset/claset for modifying the simpset/claset reference of a
  1618 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1619 INCOMPATIBILITY.
  1620 
  1621 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1622 "Trueprop" etc.
  1623 
  1624 
  1625 *** System ***
  1626 
  1627 * settings: the default heap location within ISABELLE_HOME_USER now
  1628 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  1629 Isabelle installations.
  1630 
  1631 * isabelle-process: option -S (secure mode) disables some critical
  1632 operations, notably runtime compilation and evaluation of ML source
  1633 code.
  1634 
  1635 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  1636 
  1637 * Support for parallel execution, using native multicore support of
  1638 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  1639 independent theories, according to the given theory header
  1640 specifications. The maximum number of worker threads is specified via
  1641 usedir option -M or the "max-threads" setting in Proof General. A
  1642 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  1643 to 6 on a 8-core machine.  User-code needs to observe certain
  1644 guidelines for thread-safe programming, see appendix A in the Isar
  1645 Implementation manual.
  1646 
  1647 
  1648 
  1649 New in Isabelle2005 (October 2005)
  1650 ----------------------------------
  1651 
  1652 *** General ***
  1653 
  1654 * Theory headers: the new header syntax for Isar theories is
  1655 
  1656   theory <name>
  1657   imports <theory1> ... <theoryN>
  1658   uses <file1> ... <fileM>
  1659   begin
  1660 
  1661 where the 'uses' part is optional.  The previous syntax
  1662 
  1663   theory <name> = <theory1> + ... + <theoryN>:
  1664 
  1665 will disappear in the next release.  Use isatool fixheaders to convert
  1666 existing theory files.  Note that there is no change in ancient
  1667 non-Isar theories now, but these will disappear soon.
  1668 
  1669 * Theory loader: parent theories can now also be referred to via
  1670 relative and absolute paths.
  1671 
  1672 * Command 'find_theorems' searches for a list of criteria instead of a
  1673 list of constants. Known criteria are: intro, elim, dest, name:string,
  1674 simp:term, and any term. Criteria can be preceded by '-' to select
  1675 theorems that do not match. Intro, elim, dest select theorems that
  1676 match the current goal, name:s selects theorems whose fully qualified
  1677 name contain s, and simp:term selects all simplification rules whose
  1678 lhs match term.  Any other term is interpreted as pattern and selects
  1679 all theorems matching the pattern. Available in ProofGeneral under
  1680 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1681 
  1682   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1683 
  1684 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1685 matching the current goal as introduction rule and not having "HOL."
  1686 in their name (i.e. not being defined in theory HOL).
  1687 
  1688 * Command 'thms_containing' has been discontinued in favour of
  1689 'find_theorems'; INCOMPATIBILITY.
  1690 
  1691 * Communication with Proof General is now 8bit clean, which means that
  1692 Unicode text in UTF-8 encoding may be used within theory texts (both
  1693 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1694 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1695 
  1696   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1697   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1698 
  1699 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1700 Classical Reasoner.  Typical big applications run around 2 times
  1701 faster.
  1702 
  1703 
  1704 *** Document preparation ***
  1705 
  1706 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1707 of raw sources.  Only those symbols that do not require additional
  1708 LaTeX packages (depending on comments in isabellesym.sty) are
  1709 displayed properly, everything else is left verbatim.  isatool display
  1710 and isatool print are used as front ends (these are subject to the
  1711 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1712 
  1713 * Command tags control specific markup of certain regions of text,
  1714 notably folding and hiding.  Predefined tags include "theory" (for
  1715 theory begin and end), "proof" for proof commands, and "ML" for
  1716 commands involving ML code; the additional tags "visible" and
  1717 "invisible" are unused by default.  Users may give explicit tag
  1718 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1719 interpretation of tags is determined by the LaTeX job during document
  1720 preparation: see option -V of isatool usedir, or options -n and -t of
  1721 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1722 \isadroptag.
  1723 
  1724 Several document versions may be produced at the same time via isatool
  1725 usedir (the generated index.html will link all of them).  Typical
  1726 specifications include ''-V document=theory,proof,ML'' to present
  1727 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1728 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1729 these parts without any formal replacement text.  The Isabelle site
  1730 default settings produce ''document'' and ''outline'' versions as
  1731 specified above.
  1732 
  1733 * Several new antiquotations:
  1734 
  1735   @{term_type term} prints a term with its type annotated;
  1736 
  1737   @{typeof term} prints the type of a term;
  1738 
  1739   @{const const} is the same as @{term const}, but checks that the
  1740   argument is a known logical constant;
  1741 
  1742   @{term_style style term} and @{thm_style style thm} print a term or
  1743   theorem applying a "style" to it
  1744 
  1745   @{ML text}
  1746 
  1747 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1748 definitions, equations, inequations etc., 'concl' printing only the
  1749 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1750 to print the specified premise.  TermStyle.add_style provides an ML
  1751 interface for introducing further styles.  See also the "LaTeX Sugar"
  1752 document practical applications.  The ML antiquotation prints
  1753 type-checked ML expressions verbatim.
  1754 
  1755 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1756 and 'text' support optional locale specification '(in loc)', which
  1757 specifies the default context for interpreting antiquotations.  For
  1758 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1759 
  1760 * Option 'locale=NAME' of antiquotations specifies an alternative
  1761 context interpreting the subsequent argument.  For example: @{thm
  1762 [locale=lattice] inf_assoc}.
  1763 
  1764 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1765 a proof context.
  1766 
  1767 * Proper output of antiquotations for theory commands involving a
  1768 proof context (such as 'locale' or 'theorem (in loc) ...').
  1769 
  1770 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1771 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1772 
  1773 * isatool usedir: new option -C (default true) controls whether option
  1774 -D should include a copy of the original document directory; -C false
  1775 prevents unwanted effects such as copying of administrative CVS data.
  1776 
  1777 
  1778 *** Pure ***
  1779 
  1780 * Considerably improved version of 'constdefs' command.  Now performs
  1781 automatic type-inference of declared constants; additional support for
  1782 local structure declarations (cf. locales and HOL records), see also
  1783 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1784 sequential dependencies of definitions within a single 'constdefs'
  1785 section; moreover, the declared name needs to be an identifier.  If
  1786 all fails, consider to fall back on 'consts' and 'defs' separately.
  1787 
  1788 * Improved indexed syntax and implicit structures.  First of all,
  1789 indexed syntax provides a notational device for subscripted
  1790 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1791 expressions.  Secondly, in a local context with structure
  1792 declarations, number indexes \<^sub>n or the empty index (default
  1793 number 1) refer to a certain fixed variable implicitly; option
  1794 show_structs controls printing of implicit structures.  Typical
  1795 applications of these concepts involve record types and locales.
  1796 
  1797 * New command 'no_syntax' removes grammar declarations (and
  1798 translations) resulting from the given syntax specification, which is
  1799 interpreted in the same manner as for the 'syntax' command.
  1800 
  1801 * 'Advanced' translation functions (parse_translation etc.) may depend
  1802 on the signature of the theory context being presently used for
  1803 parsing/printing, see also isar-ref manual.
  1804 
  1805 * Improved 'oracle' command provides a type-safe interface to turn an
  1806 ML expression of type theory -> T -> term into a primitive rule of
  1807 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1808 is already included here); see also FOL/ex/IffExample.thy;
  1809 INCOMPATIBILITY.
  1810 
  1811 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1812 before); "cI" is no longer bound, use "c.intro" instead.
  1813 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1814 axclasses vs. locales.
  1815 
  1816 * Improved internal renaming of symbolic identifiers -- attach primes
  1817 instead of base 26 numbers.
  1818 
  1819 * New flag show_question_marks controls printing of leading question
  1820 marks in schematic variable names.
  1821 
  1822 * In schematic variable names, *any* symbol following \<^isub> or
  1823 \<^isup> is now treated as part of the base name.  For example, the
  1824 following works without printing of awkward ".0" indexes:
  1825 
  1826   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1827     by simp
  1828 
  1829 * Inner syntax includes (*(*nested*) comments*).
  1830 
  1831 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1832 annotations as "(00...)".
  1833 
  1834 * Clear separation of logical types and nonterminals, where the latter
  1835 may only occur in 'syntax' specifications or type abbreviations.
  1836 Before that distinction was only partially implemented via type class
  1837 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1838 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1839 exotic syntax specifications may require further adaption
  1840 (e.g. Cube/Cube.thy).
  1841 
  1842 * Removed obsolete type class "logic", use the top sort {} instead.
  1843 Note that non-logical types should be declared as 'nonterminals'
  1844 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1845 specifications.
  1846 
  1847 * Attributes 'induct' and 'cases': type or set names may now be
  1848 locally fixed variables as well.
  1849 
  1850 * Simplifier: can now control the depth to which conditional rewriting
  1851 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1852 Limit.
  1853 
  1854 * Simplifier: simplification procedures may now take the current
  1855 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1856 interface), which is very useful for calling the Simplifier
  1857 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1858 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1859 low-level mk_simproc no longer applies Logic.varify internally, to
  1860 allow for use in a context of fixed variables.
  1861 
  1862 * thin_tac now works even if the assumption being deleted contains !!
  1863 or ==>.  More generally, erule now works even if the major premise of
  1864 the elimination rule contains !! or ==>.
  1865 
  1866 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1867 
  1868 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1869 from Pure, which contains all common declarations already.  Both
  1870 theories are defined via plain Isabelle/Isar .thy files.
  1871 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1872 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1873 use isatool fixcpure to adapt your theory and ML sources.
  1874 
  1875 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1876 selections of theorems in named facts via index ranges.
  1877 
  1878 * 'print_theorems': in theory mode, really print the difference
  1879 wrt. the last state (works for interactive theory development only),
  1880 in proof mode print all local facts (cf. 'print_facts');
  1881 
  1882 * 'hide': option '(open)' hides only base names.
  1883 
  1884 * More efficient treatment of intermediate checkpoints in interactive
  1885 theory development.
  1886 
  1887 * Code generator is now invoked via code_module (incremental code
  1888 generation) and code_library (modular code generation, ML structures
  1889 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1890 must be quoted when used as identifiers.
  1891 
  1892 * New 'value' command for reading, evaluating and printing terms using
  1893 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1894 quoted when used as identifier.
  1895 
  1896 
  1897 *** Locales ***
  1898 
  1899 * New commands for the interpretation of locale expressions in
  1900 theories (1), locales (2) and proof contexts (3).  These generate
  1901 proof obligations from the expression specification.  After the
  1902 obligations have been discharged, theorems of the expression are added
  1903 to the theory, target locale or proof context.  The synopsis of the
  1904 commands is a follows:
  1905 
  1906   (1) interpretation expr inst
  1907   (2) interpretation target < expr
  1908   (3) interpret expr inst
  1909 
  1910 Interpretation in theories and proof contexts require a parameter
  1911 instantiation of terms from the current context.  This is applied to
  1912 specifications and theorems of the interpreted expression.
  1913 Interpretation in locales only permits parameter renaming through the
  1914 locale expression.  Interpretation is smart in that interpretations
  1915 that are active already do not occur in proof obligations, neither are
  1916 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1917 inspect active interpretations of a particular locale.  For details,
  1918 see the Isar Reference manual.  Examples can be found in
  1919 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1920 
  1921 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1922 'interpret' instead.
  1923 
  1924 * New context element 'constrains' for adding type constraints to
  1925 parameters.
  1926 
  1927 * Context expressions: renaming of parameters with syntax
  1928 redeclaration.
  1929 
  1930 * Locale declaration: 'includes' disallowed.
  1931 
  1932 * Proper static binding of attribute syntax -- i.e. types / terms /
  1933 facts mentioned as arguments are always those of the locale definition
  1934 context, independently of the context of later invocations.  Moreover,
  1935 locale operations (renaming and type / term instantiation) are applied
  1936 to attribute arguments as expected.
  1937 
  1938 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1939 actual attributes; rare situations may require Attrib.attribute to
  1940 embed those attributes into Attrib.src that lack concrete syntax.
  1941 Attribute implementations need to cooperate properly with the static
  1942 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1943 Attrib.XXX_thm etc. already do the right thing without further
  1944 intervention.  Only unusual applications -- such as "where" or "of"
  1945 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1946 on the context and the facts involved -- may have to assign parsed
  1947 values to argument tokens explicitly.
  1948 
  1949 * Changed parameter management in theorem generation for long goal
  1950 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1951 theorem statement in rare situations.
  1952 
  1953 * Locale inspection command 'print_locale' omits notes elements.  Use
  1954 'print_locale!' to have them included in the output.
  1955 
  1956 
  1957 *** Provers ***
  1958 
  1959 * Provers/hypsubst.ML: improved version of the subst method, for
  1960 single-step rewriting: it now works in bound variable contexts. New is
  1961 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1962 rewrite a different subterm than the original subst method, which is
  1963 still available as 'simplesubst'.
  1964 
  1965 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1966 and quasi orders.
  1967 
  1968 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1969 reflexive-transitive closure of relations.
  1970 
  1971 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1972 limit (previously hard-coded with a value of 20) user-definable.
  1973 
  1974 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1975 is peformed already.  Object-logics merely need to finish their
  1976 initial simpset configuration as before.  INCOMPATIBILITY.
  1977 
  1978 
  1979 *** HOL ***
  1980 
  1981 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1982 
  1983   syntax (epsilon)
  1984     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1985 
  1986 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1987 and x-symbol; use option '-m epsilon' to get it actually printed.
  1988 Moreover, the mathematically important symbolic identifier \<epsilon>
  1989 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1990 
  1991 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1992 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1993 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1994 support corresponding Isar calculations.
  1995 
  1996 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1997 instead of ":".
  1998 
  1999 * theory SetInterval: changed the syntax for open intervals:
  2000 
  2001   Old       New
  2002   {..n(}    {..<n}
  2003   {)n..}    {n<..}
  2004   {m..n(}   {m..<n}
  2005   {)m..n}   {m<..n}
  2006   {)m..n(}  {m<..<n}
  2007 
  2008 The old syntax is still supported but will disappear in the next
  2009 release.  For conversion use the following Emacs search and replace
  2010 patterns (these are not perfect but work quite well):
  2011 
  2012   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2013   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2014 
  2015 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2016 equalities in commutative rings; method 'algebra' provides a generic
  2017 interface.
  2018 
  2019 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2020 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2021 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2022 be a tuple pattern.
  2023 
  2024 Some new syntax forms are available:
  2025 
  2026   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2027   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2028   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2029   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2030 
  2031 The latter form "\<Sum>x < k. e" used to be based on a separate
  2032 function "Summation", which has been discontinued.
  2033 
  2034 * theory Finite_Set: in structured induction proofs, the insert case
  2035 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2036 (insert F x)'.
  2037 
  2038 * The 'refute' command has been extended to support a much larger
  2039 fragment of HOL, including axiomatic type classes, constdefs and
  2040 typedefs, inductive datatypes and recursion.
  2041 
  2042 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2043 Requires zChaff with proof generation to be installed.  See
  2044 HOL/ex/SAT_Examples.thy for examples.
  2045 
  2046 * Datatype induction via method 'induct' now preserves the name of the
  2047 induction variable. For example, when proving P(xs::'a list) by
  2048 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2049 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2050 in unstructured proof scripts.
  2051 
  2052 * Reworked implementation of records.  Improved scalability for
  2053 records with many fields, avoiding performance problems for type
  2054 inference. Records are no longer composed of nested field types, but
  2055 of nested extension types. Therefore the record type only grows linear
  2056 in the number of extensions and not in the number of fields.  The
  2057 top-level (users) view on records is preserved.  Potential
  2058 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2059 old record representation. The type generated for a record is called
  2060 <record_name>_ext_type.
  2061 
  2062 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2063 proofs triggered by a record definition or a simproc (if
  2064 quick_and_dirty is enabled).  Definitions of large records can take
  2065 quite long.
  2066 
  2067 New simproc record_upd_simproc for simplification of multiple record
  2068 updates enabled by default.  Moreover, trivial updates are also
  2069 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2070 occasionally, since simplification is more powerful by default.
  2071 
  2072 * typedef: proper support for polymorphic sets, which contain extra
  2073 type-variables in the term.
  2074 
  2075 * Simplifier: automatically reasons about transitivity chains
  2076 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2077 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2078 old proofs break occasionally as simplification may now solve more
  2079 goals than previously.
  2080 
  2081 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2082 present.  Works for all partial orders (class "order"), in particular
  2083 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2084 just like y <= x.
  2085 
  2086 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2087 bound variable or a constant then the let is unfolded.  Otherwise
  2088 first a is simplified to b, and then f b is simplified to g. If
  2089 possible we abstract b from g arriving at "let x = b in h x",
  2090 otherwise we unfold the let and arrive at g.  The simproc can be
  2091 enabled/disabled by the reference use_let_simproc.  Potential
  2092 INCOMPATIBILITY since simplification is more powerful by default.
  2093 
  2094 * Classical reasoning: the meson method now accepts theorems as arguments.
  2095 
  2096 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2097 jobs to provide advice on the provability of subgoals.
  2098 
  2099 * Theory OrderedGroup and Ring_and_Field: various additions and
  2100 improvements to faciliate calculations involving equalities and
  2101 inequalities.
  2102 
  2103 The following theorems have been eliminated or modified
  2104 (INCOMPATIBILITY):
  2105 
  2106   abs_eq             now named abs_of_nonneg
  2107   abs_of_ge_0        now named abs_of_nonneg
  2108   abs_minus_eq       now named abs_of_nonpos
  2109   imp_abs_id         now named abs_of_nonneg
  2110   imp_abs_neg_id     now named abs_of_nonpos
  2111   mult_pos           now named mult_pos_pos
  2112   mult_pos_le        now named mult_nonneg_nonneg
  2113   mult_pos_neg_le    now named mult_nonneg_nonpos
  2114   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2115   mult_neg           now named mult_neg_neg
  2116   mult_neg_le        now named mult_nonpos_nonpos
  2117 
  2118 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2119      
  2120      zero_le_square
  2121      not_square_less_zero 
  2122 
  2123   The following lemmas have been deleted from Real/RealPow:
  2124   
  2125      realpow_zero_zero
  2126      realpow_two
  2127      realpow_less
  2128      zero_le_power
  2129      realpow_two_le
  2130      abs_realpow_two
  2131      realpow_two_abs     
  2132 
  2133 * Theory Parity: added rules for simplifying exponents.
  2134 
  2135 * Theory List:
  2136 
  2137 The following theorems have been eliminated or modified
  2138 (INCOMPATIBILITY):
  2139 
  2140   list_all_Nil       now named list_all.simps(1)
  2141   list_all_Cons      now named list_all.simps(2)
  2142   list_all_conv      now named list_all_iff
  2143   set_mem_eq         now named mem_iff
  2144 
  2145 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2146 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2147 
  2148 
  2149 *** HOL-Complex ***
  2150 
  2151 * Theory RealDef: better support for embedding natural numbers and
  2152 integers in the reals.
  2153 
  2154 The following theorems have been eliminated or modified
  2155 (INCOMPATIBILITY):
  2156 
  2157   exp_ge_add_one_self  now requires no hypotheses
  2158   real_of_int_add      reversed direction of equality (use [symmetric])
  2159   real_of_int_minus    reversed direction of equality (use [symmetric])
  2160   real_of_int_diff     reversed direction of equality (use [symmetric])
  2161   real_of_int_mult     reversed direction of equality (use [symmetric])
  2162 
  2163 * Theory RComplete: expanded support for floor and ceiling functions.
  2164 
  2165 * Theory Ln is new, with properties of the natural logarithm
  2166 
  2167 * Hyperreal: There is a new type constructor "star" for making
  2168 nonstandard types.  The old type names are now type synonyms:
  2169 
  2170   hypreal = real star
  2171   hypnat = nat star
  2172   hcomplex = complex star
  2173 
  2174 * Hyperreal: Many groups of similarly-defined constants have been
  2175 replaced by polymorphic versions (INCOMPATIBILITY):
  2176 
  2177   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2178 
  2179   starset      <-- starsetNat, starsetC
  2180   *s*          <-- *sNat*, *sc*
  2181   starset_n    <-- starsetNat_n, starsetC_n
  2182   *sn*         <-- *sNatn*, *scn*
  2183   InternalSets <-- InternalNatSets, InternalCSets
  2184 
  2185   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2186   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2187   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2188   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2189   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2190 
  2191 * Hyperreal: Many type-specific theorems have been removed in favor of
  2192 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2193 
  2194   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2195   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2196   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2197   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2198   right_minus <-- hypreal_add_minus
  2199   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2200   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2201   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2202   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2203   mult_1_right <-- hcomplex_mult_one_right
  2204   mult_zero_left <-- hcomplex_mult_zero_left
  2205   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2206   right_distrib <-- hypnat_add_mult_distrib2
  2207   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2208   right_inverse <-- hypreal_mult_inverse
  2209   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2210   order_refl <-- {hypreal,hypnat}_le_refl
  2211   order_trans <-- {hypreal,hypnat}_le_trans
  2212   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2213   order_less_le <-- {hypreal,hypnat}_less_le
  2214   linorder_linear <-- {hypreal,hypnat}_le_linear
  2215   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2216   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2217   add_nonneg_nonneg <-- hypreal_le_add_order
  2218 
  2219 * Hyperreal: Separate theorems having to do with type-specific
  2220 versions of constants have been merged into theorems that apply to the
  2221 new polymorphic constants (INCOMPATIBILITY):
  2222 
  2223   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2224   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2225   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2226   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2227   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2228   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2229   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2230   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2231   STAR_diff <-- {STAR,STARC}_diff
  2232   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2233     STARC_hcomplex_of_complex}_image_subset
  2234   starset_n_Un <-- starset{Nat,C}_n_Un
  2235   starset_n_Int <-- starset{Nat,C}_n_Int
  2236   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2237   starset_n_diff <-- starset{Nat,C}_n_diff
  2238   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2239   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2240   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2241   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2242   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2243   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2244   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2245   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2246   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2247   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2248   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2249   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2250   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2251   starfun_diff <-- starfun{C,RC,CR}_diff
  2252   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2253   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2254   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2255   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2256   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2257   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2258   starfun_Id <-- starfunC_Id
  2259   starfun_approx <-- starfun{Nat,CR}_approx
  2260   starfun_capprox <-- starfun{C,RC}_capprox
  2261   starfun_abs <-- starfunNat_rabs
  2262   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2263   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2264   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2265   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2266   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2267   starfun_add_approx <-- starfunCR_add_approx
  2268   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2269   starfun_divide <-- starfun{C,CR,RC}_divide
  2270   starfun_n <-- starfun{Nat,C}_n
  2271   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2272   starfun_n_add <-- starfun{Nat,C}_n_add
  2273   starfun_n_add_minus <-- starfunNat_n_add_minus
  2274   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2275   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2276   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2277 
  2278   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2279   star_n_minus <-- {hypreal,hcomplex}_minus
  2280   star_n_diff <-- {hypreal,hcomplex}_diff
  2281   star_n_mult <-- {hypreal,hcomplex}_mult
  2282   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2283   star_n_le <-- {hypreal,hypnat}_le
  2284   star_n_less <-- {hypreal,hypnat}_less
  2285   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2286   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2287   star_n_abs <-- hypreal_hrabs
  2288   star_n_divide <-- hcomplex_divide
  2289 
  2290   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2291   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2292   star_of_diff <-- hypreal_of_real_diff
  2293   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2294   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2295   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2296   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2297   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2298   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2299   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2300   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2301   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2302   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2303   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2304   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2305   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2306   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2307   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2308   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2309   star_of_power <-- hypreal_of_real_power
  2310   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2311 
  2312 * Hyperreal: new method "transfer" that implements the transfer
  2313 principle of nonstandard analysis. With a subgoal that mentions
  2314 nonstandard types like "'a star", the command "apply transfer"
  2315 replaces it with an equivalent one that mentions only standard types.
  2316 To be successful, all free variables must have standard types; non-
  2317 standard variables must have explicit universal quantifiers.
  2318 
  2319 * Hyperreal: A theory of Taylor series.
  2320 
  2321 
  2322 *** HOLCF ***
  2323 
  2324 * Discontinued special version of 'constdefs' (which used to support
  2325 continuous functions) in favor of the general Pure one with full
  2326 type-inference.
  2327 
  2328 * New simplification procedure for solving continuity conditions; it
  2329 is much faster on terms with many nested lambda abstractions (cubic
  2330 instead of exponential time).
  2331 
  2332 * New syntax for domain package: selector names are now optional.
  2333 Parentheses should be omitted unless argument is lazy, for example:
  2334 
  2335   domain 'a stream = cons "'a" (lazy "'a stream")
  2336 
  2337 * New command 'fixrec' for defining recursive functions with pattern
  2338 matching; defining multiple functions with mutual recursion is also
  2339 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2340 sinr, or any data constructor defined by the domain package. The given
  2341 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2342 syntax and examples.
  2343 
  2344 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2345 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2346 but the proof obligation additionally includes an admissibility
  2347 requirement. The packages generate instances of class cpo or pcpo,
  2348 with continuity and strictness theorems for Rep and Abs.
  2349 
  2350 * HOLCF: Many theorems have been renamed according to a more standard naming
  2351 scheme (INCOMPATIBILITY):
  2352 
  2353   foo_inject:  "foo$x = foo$y ==> x = y"
  2354   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2355   foo_less:    "(foo$x << foo$y) = (x << y)"
  2356   foo_strict:  "foo$UU = UU"
  2357   foo_defined: "... ==> foo$x ~= UU"
  2358   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2359 
  2360 
  2361 *** ZF ***
  2362 
  2363 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2364 including the First Isomorphism Theorem (on quotienting by the kernel
  2365 of a homomorphism).
  2366 
  2367 * ZF/Simplifier: install second copy of type solver that actually
  2368 makes use of TC rules declared to Isar proof contexts (or locales);
  2369 the old version is still required for ML proof scripts.
  2370 
  2371 
  2372 *** Cube ***
  2373 
  2374 * Converted to Isar theory format; use locales instead of axiomatic
  2375 theories.
  2376 
  2377 
  2378 *** ML ***
  2379 
  2380 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2381 for ||>, ||>>, |>>,
  2382 
  2383 * Pure/library.ML no longer defines its own option datatype, but uses
  2384 that of the SML basis, which has constructors NONE and SOME instead of
  2385 None and Some, as well as exception Option.Option instead of OPTION.
  2386 The functions the, if_none, is_some, is_none have been adapted
  2387 accordingly, while Option.map replaces apsome.
  2388 
  2389 * Pure/library.ML: the exception LIST has been given up in favour of
  2390 the standard exceptions Empty and Subscript, as well as
  2391 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2392 superceded by the standard hd and tl functions etc.
  2393 
  2394 A number of basic list functions are no longer exported to the ML
  2395 toplevel, as they are variants of predefined functions.  The following
  2396 suggests how one can translate existing code:
  2397 
  2398     rev_append xs ys = List.revAppend (xs, ys)
  2399     nth_elem (i, xs) = List.nth (xs, i)
  2400     last_elem xs = List.last xs
  2401     flat xss = List.concat xss
  2402     seq fs = List.app fs
  2403     partition P xs = List.partition P xs
  2404     mapfilter f xs = List.mapPartial f xs
  2405 
  2406 * Pure/library.ML: several combinators for linear functional
  2407 transformations, notably reverse application and composition:
  2408 
  2409   x |> f                f #> g
  2410   (x, y) |-> f          f #-> g
  2411 
  2412 * Pure/library.ML: introduced/changed precedence of infix operators:
  2413 
  2414   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2415   infix 2 ?;
  2416   infix 3 o oo ooo oooo;
  2417   infix 4 ~~ upto downto;
  2418 
  2419 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2420 infix operators.
  2421 
  2422 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2423 fold_map support linear functional transformations and nesting.  For
  2424 example:
  2425 
  2426   fold f [x1, ..., xN] y =
  2427     y |> f x1 |> ... |> f xN
  2428 
  2429   (fold o fold) f [xs1, ..., xsN] y =
  2430     y |> fold f xs1 |> ... |> fold f xsN
  2431 
  2432   fold f [x1, ..., xN] =
  2433     f x1 #> ... #> f xN
  2434 
  2435   (fold o fold) f [xs1, ..., xsN] =
  2436     fold f xs1 #> ... #> fold f xsN
  2437 
  2438 * Pure/library.ML: the following selectors on type 'a option are
  2439 available:
  2440 
  2441   the:               'a option -> 'a  (*partial*)
  2442   these:             'a option -> 'a  where 'a = 'b list
  2443   the_default: 'a -> 'a option -> 'a
  2444   the_list:          'a option -> 'a list
  2445 
  2446 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2447 basic operations for association lists, following natural argument
  2448 order; moreover the explicit equality predicate passed here avoids
  2449 potentially expensive polymorphic runtime equality checks.
  2450 The old functions may be expressed as follows:
  2451 
  2452   assoc = uncurry (AList.lookup (op =))
  2453   assocs = these oo AList.lookup (op =)
  2454   overwrite = uncurry (AList.update (op =)) o swap
  2455 
  2456 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2457 
  2458   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2459   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2460 
  2461 replacing make_keylist and keyfilter (occassionally used)
  2462 Naive rewrites:
  2463 
  2464   make_keylist = AList.make
  2465   keyfilter = AList.find (op =)
  2466 
  2467 * eq_fst and eq_snd now take explicit equality parameter, thus
  2468   avoiding eqtypes. Naive rewrites:
  2469 
  2470     eq_fst = eq_fst (op =)
  2471     eq_snd = eq_snd (op =)
  2472 
  2473 * Removed deprecated apl and apr (rarely used).
  2474   Naive rewrites:
  2475 
  2476     apl (n, op) =>>= curry op n
  2477     apr (op, m) =>>= fn n => op (n, m)
  2478 
  2479 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2480 provides a reasonably efficient light-weight implementation of sets as
  2481 lists.
  2482 
  2483 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2484 few new operations; existing lookup and update are now curried to
  2485 follow natural argument order (for use with fold etc.);
  2486 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2487 
  2488 * Pure/General: output via the Isabelle channels of
  2489 writeln/warning/error etc. is now passed through Output.output, with a
  2490 hook for arbitrary transformations depending on the print_mode
  2491 (cf. Output.add_mode -- the first active mode that provides a output
  2492 function wins).  Already formatted output may be embedded into further
  2493 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2494 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2495 accommodate easy composition of diagnostic messages etc.  Programmers
  2496 rarely need to care about Output.output or Output.raw at all, with
  2497 some notable exceptions: Output.output is required when bypassing the
  2498 standard channels (writeln etc.), or in token translations to produce
  2499 properly formatted results; Output.raw is required when capturing
  2500 already output material that will eventually be presented to the user
  2501 a second time.  For the default print mode, both Output.output and
  2502 Output.raw have no effect.
  2503 
  2504 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2505 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2506 cumulative results are displayed at the end of a batch session.
  2507 
  2508 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2509 replaced by File.platform_path and File.shell_path (with appropriate
  2510 hooks).  This provides a clean interface for unusual systems where the
  2511 internal and external process view of file names are different.
  2512 
  2513 * Pure: more efficient orders for basic syntactic entities: added
  2514 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2515 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2516 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2517 orders now -- potential INCOMPATIBILITY for code that depends on a
  2518 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2519 Library.sort_strings on result).
  2520 
  2521 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2522 fold_types traverse types/terms from left to right, observing natural
  2523 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2524 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2525 
  2526 * Pure: name spaces have been refined, with significant changes of the
  2527 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2528 to extern(_table).  The plain name entry path is superceded by a
  2529 general 'naming' context, which also includes the 'policy' to produce
  2530 a fully qualified name and external accesses of a fully qualified
  2531 name; NameSpace.extend is superceded by context dependent
  2532 Sign.declare_name.  Several theory and proof context operations modify
  2533 the naming context.  Especially note Theory.restore_naming and
  2534 ProofContext.restore_naming to get back to a sane state; note that
  2535 Theory.add_path is no longer sufficient to recover from
  2536 Theory.absolute_path in particular.
  2537 
  2538 * Pure: new flags short_names (default false) and unique_names
  2539 (default true) for controlling output of qualified names.  If
  2540 short_names is set, names are printed unqualified.  If unique_names is
  2541 reset, the name prefix is reduced to the minimum required to achieve
  2542 the original result when interning again, even if there is an overlap
  2543 with earlier declarations.
  2544 
  2545 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2546 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2547 (useful for printing error messages).  INCOMPATIBILITY.
  2548 
  2549 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2550 Theory.theory are now identified, referring to the universal
  2551 Context.theory (see Pure/context.ML).  Actual signature and theory
  2552 content is managed as theory data.  The old code and interfaces were
  2553 spread over many files and structures; the new arrangement introduces
  2554 considerable INCOMPATIBILITY to gain more clarity:
  2555 
  2556   Context -- theory management operations (name, identity, inclusion,
  2557     parents, ancestors, merge, etc.), plus generic theory data;
  2558 
  2559   Sign -- logical signature and syntax operations (declaring consts,
  2560     types, etc.), plus certify/read for common entities;
  2561 
  2562   Theory -- logical theory operations (stating axioms, definitions,
  2563     oracles), plus a copy of logical signature operations (consts,
  2564     types, etc.); also a few basic management operations (Theory.copy,
  2565     Theory.merge, etc.)
  2566 
  2567 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2568 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2569 for convenience -- they merely return the theory.
  2570 
  2571 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2572 
  2573 * Pure: the Isar proof context type is already defined early in Pure
  2574 as Context.proof (note that ProofContext.context and Proof.context are
  2575 aliases, where the latter is the preferred name).  This enables other
  2576 Isabelle components to refer to that type even before Isar is present.
  2577 
  2578 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2579 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2580 any of these kinds.  For example, Sign.intern typeK is now
  2581 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2582 Theory.hide_types.  Also note that former
  2583 Theory.hide_classes/types/consts are now
  2584 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2585 internalize their arguments!  INCOMPATIBILITY.
  2586 
  2587 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2588 datatype thmref (with constructors Name and NameSelection) instead of
  2589 plain string -- INCOMPATIBILITY;
  2590 
  2591 * Pure: cases produced by proof methods specify options, where NONE
  2592 means to remove case bindings -- INCOMPATIBILITY in
  2593 (RAW_)METHOD_CASES.
  2594 
  2595 * Pure: the following operations retrieve axioms or theorems from a
  2596 theory node or theory hierarchy, respectively:
  2597 
  2598   Theory.axioms_of: theory -> (string * term) list
  2599   Theory.all_axioms_of: theory -> (string * term) list
  2600   PureThy.thms_of: theory -> (string * thm) list
  2601   PureThy.all_thms_of: theory -> (string * thm) list
  2602 
  2603 * Pure: print_tac now outputs the goal through the trace channel.
  2604 
  2605 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2606 Reference Toplevel.debug (default false) controls detailed printing
  2607 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2608 controls execution profiling -- set to 1 for time and 2 for space
  2609 (both increase the runtime).
  2610 
  2611 * Isar session: The initial use of ROOT.ML is now always timed,
  2612 i.e. the log will show the actual process times, in contrast to the
  2613 elapsed wall-clock time that the outer shell wrapper produces.
  2614 
  2615 * Simplifier: improved handling of bound variables (nameless
  2616 representation, avoid allocating new strings).  Simprocs that invoke
  2617 the Simplifier recursively should use Simplifier.inherit_bounds to
  2618 avoid local name clashes.  Failure to do so produces warnings
  2619 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2620 for further details.
  2621 
  2622 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2623 bindings for all theorems stored within a given theory; this may help
  2624 in porting non-Isar theories to Isar ones, while keeping ML proof
  2625 scripts for the time being.
  2626 
  2627 * ML operator HTML.with_charset specifies the charset begin used for
  2628 generated HTML files.  For example:
  2629 
  2630   HTML.with_charset "utf-8" use_thy "Hebrew";
  2631   HTML.with_charset "utf-8" use_thy "Chinese";
  2632 
  2633 
  2634 *** System ***
  2635 
  2636 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2637 isabelle, isatool etc.).
  2638 
  2639 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2640 isatool doc, isatool mkdir, display_drafts etc.).
  2641 
  2642 * isatool usedir: option -f allows specification of the ML file to be
  2643 used by Isabelle; default is ROOT.ML.
  2644 
  2645 * New isatool version outputs the version identifier of the Isabelle
  2646 distribution being used.
  2647 
  2648 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2649 (containing Boolean satisfiability problems) into Isabelle/HOL
  2650 theories.
  2651 
  2652 
  2653 
  2654 New in Isabelle2004 (April 2004)
  2655 --------------------------------
  2656 
  2657 *** General ***
  2658 
  2659 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2660   Replaces linorder.ML.
  2661 
  2662 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2663   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2664   (\<a>...\<z>), are now considered normal letters, and can therefore
  2665   be used anywhere where an ASCII letter (a...zA...Z) has until
  2666   now. COMPATIBILITY: This obviously changes the parsing of some
  2667   terms, especially where a symbol has been used as a binder, say
  2668   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2669   as an identifier.  Fix it by inserting a space around former
  2670   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2671   existing theory and ML files.
  2672 
  2673 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2674 
  2675 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2676   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2677   a normal (but invisible) letter. For multiple letter subscripts repeat
  2678   \<^isub> like this: x\<^isub>1\<^isub>2.
  2679 
  2680 * Pure: There are now sub-/superscripts that can span more than one
  2681   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2682   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2683   superscript. The new control characters are not identifier parts.
  2684 
  2685 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2686   content of "..." to the latex file instead of \isacntrl... . The "..."
  2687   may consist of any printable characters excluding the end bracket >.
  2688 
  2689 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2690   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2691   declare constants "final", which prevents their being given a definition
  2692   later.  It is useful for constants whose behaviour is fixed axiomatically
  2693   rather than definitionally, such as the meta-logic connectives.
  2694 
  2695 * Pure: 'instance' now handles general arities with general sorts
  2696   (i.e. intersections of classes),
  2697 
  2698 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2699   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2700   It can be changed to alter the colors/layout of generated pages.
  2701 
  2702 
  2703 *** Isar ***
  2704 
  2705 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2706   cut_tac, subgoal_tac and thin_tac:
  2707   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2708     locales are no longer forced to write Isar proof scripts.
  2709     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2710     emulations.
  2711   - INCOMPATIBILITY: names of variables to be instantiated may no
  2712     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2713     This is consistent with the instantiation attribute "where".
  2714 
  2715 * Attributes "where" and "of":
  2716   - Now take type variables of instantiated theorem into account when reading
  2717     the instantiation string.  This fixes a bug that caused instantiated
  2718     theorems to have too special types in some circumstances.
  2719   - "where" permits explicit instantiations of type variables.
  2720 
  2721 * Calculation commands "moreover" and "also" no longer interfere with
  2722   current facts ("this"), admitting arbitrary combinations with "then"
  2723   and derived forms.
  2724 
  2725 * Locales:
  2726   - Goal statements involving the context element "includes" no longer
  2727     generate theorems with internal delta predicates (those ending on
  2728     "_axioms") in the premise.
  2729     Resolve particular premise with <locale>.intro to obtain old form.
  2730   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2731     specification and "includes" elements in goal statement.
  2732   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2733     [intro?] and [elim?] (respectively) by default.
  2734   - Experimental command for instantiation of locales in proof contexts:
  2735         instantiate <label>[<attrs>]: <loc>
  2736     Instantiates locale <loc> and adds all its theorems to the current context
  2737     taking into account their attributes.  Label and attrs are optional
  2738     modifiers, like in theorem declarations.  If present, names of
  2739     instantiated theorems are qualified with <label>, and the attributes
  2740     <attrs> are applied after any attributes these theorems might have already.
  2741       If the locale has assumptions, a chained fact of the form
  2742     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2743     are derived.  The command does not support old-style locales declared
  2744     with "locale (open)".
  2745       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2746 
  2747 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2748   (Isar) contexts.
  2749 
  2750 
  2751 *** HOL ***
  2752 
  2753 * Proof import: new image HOL4 contains the imported library from
  2754   the HOL4 system with about 2500 theorems. It is imported by
  2755   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2756   can be used like any other Isabelle image.  See
  2757   HOL/Import/HOL/README for more information.
  2758 
  2759 * Simplifier:
  2760   - Much improved handling of linear and partial orders.
  2761     Reasoners for linear and partial orders are set up for type classes
  2762     "linorder" and "order" respectively, and are added to the default simpset
  2763     as solvers.  This means that the simplifier can build transitivity chains
  2764     to solve goals from the assumptions.
  2765   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2766     of blast or auto after simplification become unnecessary because the goal
  2767     is solved by simplification already.
  2768 
  2769 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2770     all proved in axiomatic type classes for semirings, rings and fields.
  2771 
  2772 * Numerics:
  2773   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2774     now formalized using the Ring_and_Field theory mentioned above.
  2775   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2776     than before, because now they are set up once in a generic manner.
  2777   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2778     Look for the general versions in Ring_and_Field (and Power if they concern
  2779     exponentiation).
  2780 
  2781 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2782 
  2783 * Records:
  2784   - Record types are now by default printed with their type abbreviation
  2785     instead of the list of all field types. This can be configured via
  2786     the reference "print_record_type_abbr".
  2787   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2788     (not enabled by default).
  2789   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2790     EX x. x = sel r to True (not enabled by default).
  2791   - Tactic "record_split_simp_tac" to split and simplify records added.
  2792 
  2793 * 'specification' command added, allowing for definition by
  2794   specification.  There is also an 'ax_specification' command that
  2795   introduces the new constants axiomatically.
  2796 
  2797 * arith(_tac) is now able to generate counterexamples for reals as well.
  2798 
  2799 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2800 
  2801 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2802   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2803 
  2804 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2805   matrix theory to linear programming.
  2806 
  2807 * Unions and Intersections:
  2808   The latex output syntax of UN and INT has been changed
  2809   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2810   i.e. the index formulae has become a subscript.
  2811   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2812 
  2813 * Unions and Intersections over Intervals:
  2814   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2815   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2816   like in normal math, and corresponding versions for < and for intersection.
  2817 
  2818 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2819   lexicographic dictonary ordering has been added as "lexord".
  2820 
  2821 * ML: the legacy theory structures Int and List have been removed. They had
  2822   conflicted with ML Basis Library structures having the same names.
  2823 
  2824 * 'refute' command added to search for (finite) countermodels.  Only works
  2825   for a fragment of HOL.  The installation of an external SAT solver is
  2826   highly recommended.  See "HOL/Refute.thy" for details.
  2827 
  2828 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2829   formulae under an assignment of free variables to random values.
  2830   In contrast to 'refute', it can deal with inductive datatypes,
  2831   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2832   for examples.
  2833 
  2834 
  2835 *** HOLCF ***
  2836 
  2837 * Streams now come with concatenation and are part of the HOLCF image
  2838 
  2839 
  2840 
  2841 New in Isabelle2003 (May 2003)
  2842 ------------------------------
  2843 
  2844 *** General ***
  2845 
  2846 * Provers/simplifier:
  2847 
  2848   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2849     Assumptions are now subject to complete mutual simplification,
  2850     not just from left to right. The simplifier now preserves
  2851     the order of assumptions.
  2852 
  2853     Potential INCOMPATIBILITY:
  2854 
  2855     -- simp sometimes diverges where the old version did
  2856        not, e.g. invoking simp on the goal
  2857 
  2858         [| P (f x); y = x; f x = f y |] ==> Q
  2859 
  2860        now gives rise to the infinite reduction sequence
  2861 
  2862         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2863 
  2864        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2865        kind of problem.
  2866 
  2867     -- Tactics combining classical reasoner and simplification (such as auto)
  2868        are also affected by this change, because many of them rely on
  2869        simp. They may sometimes diverge as well or yield a different numbers
  2870        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2871        in case of problems. Sometimes subsequent calls to the classical
  2872        reasoner will fail because a preceeding call to the simplifier too
  2873        eagerly simplified the goal, e.g. deleted redundant premises.
  2874 
  2875   - The simplifier trace now shows the names of the applied rewrite rules
  2876 
  2877   - You can limit the number of recursive invocations of the simplifier
  2878     during conditional rewriting (where the simplifie tries to solve the
  2879     conditions before applying the rewrite rule):
  2880     ML "simp_depth_limit := n"
  2881     where n is an integer. Thus you can force termination where previously
  2882     the simplifier would diverge.
  2883 
  2884   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2885 
  2886   - No longer aborts on failed congruence proof.  Instead, the
  2887     congruence is ignored.
  2888 
  2889 * Pure: New generic framework for extracting programs from constructive
  2890   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2891   as HOL/Extraction for some case studies.
  2892 
  2893 * Pure: The main goal of the proof state is no longer shown by default, only
  2894 the subgoals. This behaviour is controlled by a new flag.
  2895    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2896 (ML: Proof.show_main_goal).
  2897 
  2898 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2899 rules whose conclusion matches subgoal 1:
  2900       PG menu: Isabelle/Isar -> Show me -> matching rules
  2901 The rules are ordered by how closely they match the subgoal.
  2902 In particular, rules that solve a subgoal outright are displayed first
  2903 (or rather last, the way they are printed).
  2904 (ML: ProofGeneral.print_intros())
  2905 
  2906 * Pure: New flag trace_unify_fail causes unification to print
  2907 diagnostic information (PG: in trace buffer) when it fails. This is
  2908 useful for figuring out why single step proofs like rule, erule or
  2909 assumption failed.
  2910 
  2911 * Pure: Locale specifications now produce predicate definitions
  2912 according to the body of text (covering assumptions modulo local
  2913 definitions); predicate "loc_axioms" covers newly introduced text,
  2914 while "loc" is cumulative wrt. all included locale expressions; the
  2915 latter view is presented only on export into the global theory
  2916 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2917 on the old view without predicates;
  2918 
  2919 * Pure: predefined locales "var" and "struct" are useful for sharing
  2920 parameters (as in CASL, for example); just specify something like
  2921 ``var x + var y + struct M'' as import;
  2922 
  2923 * Pure: improved thms_containing: proper indexing of facts instead of
  2924 raw theorems; check validity of results wrt. current name space;
  2925 include local facts of proof configuration (also covers active
  2926 locales), cover fixed variables in index; may use "_" in term
  2927 specification; an optional limit for the number of printed facts may
  2928 be given (the default is 40);
  2929 
  2930 * Pure: disallow duplicate fact bindings within new-style theory files
  2931 (batch-mode only);
  2932 
  2933 * Provers: improved induct method: assumptions introduced by case
  2934 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2935 the goal statement); "foo" still refers to all facts collectively;
  2936 
  2937 * Provers: the function blast.overloaded has been removed: all constants
  2938 are regarded as potentially overloaded, which improves robustness in exchange
  2939 for slight decrease in efficiency;
  2940 
  2941 * Provers/linorder: New generic prover for transitivity reasoning over
  2942 linear orders.  Note: this prover is not efficient!
  2943 
  2944 * Isar: preview of problems to finish 'show' now produce an error
  2945 rather than just a warning (in interactive mode);
  2946 
  2947 
  2948 *** HOL ***
  2949 
  2950 * arith(_tac)
  2951 
  2952  - Produces a counter example if it cannot prove a goal.
  2953    Note that the counter example may be spurious if the goal is not a formula
  2954    of quantifier-free linear arithmetic.
  2955    In ProofGeneral the counter example appears in the trace buffer.
  2956 
  2957  - Knows about div k and mod k where k is a numeral of type nat or int.
  2958 
  2959  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2960    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2961    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2962 
  2963 * simp's arithmetic capabilities have been enhanced a bit: it now
  2964 takes ~= in premises into account (by performing a case split);
  2965 
  2966 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2967 are distributed over a sum of terms;
  2968 
  2969 * New tactic "trans_tac" and method "trans" instantiate
  2970 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2971 "<=", "<" and "=").
  2972 
  2973 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2974 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2975 
  2976 * 'typedef' command has new option "open" to suppress the set
  2977 definition;
  2978 
  2979 * functions Min and Max on finite sets have been introduced (theory
  2980 Finite_Set);
  2981 
  2982 * attribute [symmetric] now works for relations as well; it turns
  2983 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2984 
  2985 * induct over a !!-quantified statement (say !!x1..xn):
  2986   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2987 
  2988 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2989 %x. None. Warning: empty_def now refers to the previously hidden definition
  2990 of the empty set.
  2991 
  2992 * Algebra: formalization of classical algebra.  Intended as base for
  2993 any algebraic development in Isabelle.  Currently covers group theory
  2994 (up to Sylow's theorem) and ring theory (Universal Property of
  2995 Univariate Polynomials).  Contributions welcome;
  2996 
  2997 * GroupTheory: deleted, since its material has been moved to Algebra;
  2998 
  2999 * Complex: new directory of the complex numbers with numeric constants,
  3000 nonstandard complex numbers, and some complex analysis, standard and
  3001 nonstandard (Jacques Fleuriot);
  3002 
  3003 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3004 
  3005 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3006 Fleuriot);
  3007 
  3008 * Real/HahnBanach: updated and adapted to locales;
  3009 
  3010 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3011 Gray and Kramer);
  3012 
  3013 * UNITY: added the Meier-Sanders theory of progress sets;
  3014 
  3015 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3016 as abstract algorithms, instantiated to the JVM;
  3017 
  3018 * Bali: Java source language formalization. Type system, operational
  3019 semantics, axiomatic semantics. Supported language features:
  3020 classes, interfaces, objects,virtual methods, static methods,
  3021 static/instance fields, arrays, access modifiers, definite
  3022 assignment, exceptions.
  3023 
  3024 
  3025 *** ZF ***
  3026 
  3027 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3028 universe, etc.);
  3029 
  3030 * Main ZF: virtually all theories converted to new-style format;
  3031 
  3032 
  3033 *** ML ***
  3034 
  3035 * Pure: Tactic.prove provides sane interface for internal proofs;
  3036 omits the infamous "standard" operation, so this is more appropriate
  3037 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3038 
  3039 * Pure: improved error reporting of simprocs;
  3040 
  3041 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3042 up simprocs;
  3043 
  3044 
  3045 *** Document preparation ***
  3046 
  3047 * uses \par instead of \\ for line breaks in theory text. This may
  3048 shift some page breaks in large documents. To get the old behaviour
  3049 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3050 
  3051 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3052 other packages
  3053 
  3054 * \<euro> now needs package babel/greek instead of marvosym (which
  3055 broke \Rightarrow)
  3056 
  3057 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3058 textcomp package)
  3059 
  3060 
  3061 
  3062 New in Isabelle2002 (March 2002)
  3063 --------------------------------
  3064 
  3065 *** Document preparation ***
  3066 
  3067 * greatly simplified document preparation setup, including more
  3068 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3069 instructive isatool mkdir; users should basically be able to get
  3070 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3071 users may run a separate document processing stage manually like this:
  3072 "isatool usedir -D output HOL Test && isatool document Test/output";
  3073 
  3074 * theory dependency graph may now be incorporated into documents;
  3075 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3076 with \includegraphics of LaTeX;
  3077 
  3078 * proper spacing of consecutive markup elements, especially text
  3079 blocks after section headings;
  3080 
  3081 * support bold style (for single symbols only), input syntax is like
  3082 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3083 
  3084 * \<bullet> is now output as bold \cdot by default, which looks much
  3085 better in printed text;
  3086 
  3087 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3088 note that these symbols are currently unavailable in Proof General /
  3089 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3090 
  3091 * isatool latex no longer depends on changed TEXINPUTS, instead
  3092 isatool document copies the Isabelle style files to the target
  3093 location;
  3094 
  3095 
  3096 *** Isar ***
  3097 
  3098 * Pure/Provers: improved proof by cases and induction;
  3099   - 'case' command admits impromptu naming of parameters (such as
  3100     "case (Suc n)");
  3101   - 'induct' method divinates rule instantiation from the inductive
  3102     claim; no longer requires excessive ?P bindings for proper
  3103     instantiation of cases;
  3104   - 'induct' method properly enumerates all possibilities of set/type
  3105     rules; as a consequence facts may be also passed through *type*
  3106     rules without further ado;
  3107   - 'induct' method now derives symbolic cases from the *rulified*
  3108     rule (before it used to rulify cases stemming from the internal
  3109     atomized version); this means that the context of a non-atomic
  3110     statement becomes is included in the hypothesis, avoiding the
  3111     slightly cumbersome show "PROP ?case" form;
  3112   - 'induct' may now use elim-style induction rules without chaining
  3113     facts, using ``missing'' premises from the goal state; this allows
  3114     rules stemming from inductive sets to be applied in unstructured
  3115     scripts, while still benefitting from proper handling of non-atomic
  3116     statements; NB: major inductive premises need to be put first, all
  3117     the rest of the goal is passed through the induction;
  3118   - 'induct' proper support for mutual induction involving non-atomic
  3119     rule statements (uses the new concept of simultaneous goals, see
  3120     below);
  3121   - append all possible rule selections, but only use the first
  3122     success (no backtracking);
  3123   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3124   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3125   - added 'print_induct_rules' (covered by help item in recent Proof
  3126     General versions);
  3127   - moved induct/cases attributes to Pure, methods to Provers;
  3128   - generic method setup instantiated for FOL and HOL;
  3129 
  3130 * Pure: support multiple simultaneous goal statements, for example
  3131 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3132 meta-level mechanism, this acts as if several individual goals had
  3133 been stated separately; in particular common proof methods need to be
  3134 repeated in order to cover all claims; note that a single elimination
  3135 step is *not* sufficient to establish the two conjunctions, so this
  3136 fails:
  3137 
  3138   assume "A & B" then have A and B ..   (*".." fails*)
  3139 
  3140 better use "obtain" in situations as above; alternative refer to
  3141 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3142 
  3143 * Pure: proper integration with ``locales''; unlike the original
  3144 version by Florian Kammller, Isar locales package high-level proof
  3145 contexts rather than raw logical ones (e.g. we admit to include
  3146 attributes everywhere); operations on locales include merge and
  3147 rename; support for implicit arguments (``structures''); simultaneous
  3148 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3149 some examples;
  3150 
  3151 * Pure: the following commands have been ``localized'', supporting a
  3152 target locale specification "(in name)": 'lemma', 'theorem',
  3153 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3154 stored both within the locale and at the theory level (exported and
  3155 qualified by the locale name);
  3156 
  3157 * Pure: theory goals may now be specified in ``long'' form, with
  3158 ad-hoc contexts consisting of arbitrary locale elements. for example
  3159 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3160 definitions may be given, too); the result is a meta-level rule with
  3161 the context elements being discharged in the obvious way;
  3162 
  3163 * Pure: new proof command 'using' allows to augment currently used
  3164 facts after a goal statement ('using' is syntactically analogous to
  3165 'apply', but acts on the goal's facts only); this allows chained facts
  3166 to be separated into parts given before and after a claim, as in
  3167 ``from a and b have C using d and e <proof>'';
  3168 
  3169 * Pure: renamed "antecedent" case to "rule_context";
  3170 
  3171 * Pure: new 'judgment' command records explicit information about the
  3172 object-logic embedding (used by several tools internally); no longer
  3173 use hard-wired "Trueprop";
  3174 
  3175 * Pure: added 'corollary' command;
  3176 
  3177 * Pure: fixed 'token_translation' command;
  3178 
  3179 * Pure: removed obsolete 'exported' attribute;
  3180 
  3181 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3182 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3183 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3184 
  3185 * Pure: method 'atomize' presents local goal premises as object-level
  3186 statements (atomic meta-level propositions); setup controlled via
  3187 rewrite rules declarations of 'atomize' attribute; example
  3188 application: 'induct' method with proper rule statements in improper
  3189 proof *scripts*;
  3190 
  3191 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3192 now consider the syntactic context of assumptions, giving a better
  3193 chance to get type-inference of the arguments right (this is
  3194 especially important for locales);
  3195 
  3196 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3197 mode;
  3198 
  3199 * Pure/obtain: the formal conclusion "thesis", being marked as
  3200 ``internal'', may no longer be reference directly in the text;
  3201 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3202 situations;
  3203 
  3204 * Pure: generic 'sym' attribute which declares a rule both as pure
  3205 'elim?' and for the 'symmetric' operation;
  3206 
  3207 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3208 text; the fixed correlation with particular command syntax has been
  3209 discontinued;
  3210 
  3211 * Pure: new method 'rules' is particularly well-suited for proof
  3212 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3213 but often produces more compact proof terms with less detours;
  3214 
  3215 * Pure/Provers/classical: simplified integration with pure rule
  3216 attributes and methods; the classical "intro?/elim?/dest?"
  3217 declarations coincide with the pure ones; the "rule" method no longer
  3218 includes classically swapped intros; "intro" and "elim" methods no
  3219 longer pick rules from the context; also got rid of ML declarations
  3220 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3221 INCOMPATIBILITY;
  3222 
  3223 * Provers/classical: attribute 'swapped' produces classical inversions
  3224 of introduction rules;
  3225 
  3226 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3227 rules instead of full simplifier context; 'iff' attribute handles
  3228 conditional rules;
  3229 
  3230 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3231 
  3232 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3233 "(permissive)" option to recover old behavior;
  3234 
  3235 * HOL: 'inductive' no longer features separate (collective) attributes
  3236 for 'intros' (was found too confusing);
  3237 
  3238 * HOL: properly declared induction rules less_induct and
  3239 wf_induct_rule;
  3240 
  3241 
  3242 *** HOL ***
  3243 
  3244 * HOL: moved over to sane numeral syntax; the new policy is as
  3245 follows:
  3246 
  3247   - 0 and 1 are polymorphic constants, which are defined on any
  3248   numeric type (nat, int, real etc.);
  3249 
  3250   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3251   binary representation internally;
  3252 
  3253   - type nat has special constructor Suc, and generally prefers Suc 0
  3254   over 1::nat and Suc (Suc 0) over 2::nat;
  3255 
  3256 This change may cause significant problems of INCOMPATIBILITY; here
  3257 are some hints on converting existing sources:
  3258 
  3259   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3260   entities, so expressions involving "-" (unary or binary minus) need
  3261   to be spaced properly;
  3262 
  3263   - existing occurrences of "1" may need to be constraint "1::nat" or
  3264   even replaced by Suc 0; similar for old "2";
  3265 
  3266   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3267 
  3268   - remove all special provisions on numerals in proofs;
  3269 
  3270 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3271 representation (depends on bin_arith_simps in the default context);
  3272 
  3273 * HOL: symbolic syntax for x^2 (numeral 2);
  3274 
  3275 * HOL: the class of all HOL types is now called "type" rather than
  3276 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3277 in axclass/classes, instance/arities, and (usually rare) occurrences
  3278 in typings (of consts etc.); internally the class is called
  3279 "HOL.type", ML programs should refer to HOLogic.typeS;
  3280 
  3281 * HOL/record package improvements:
  3282   - new derived operations "fields" to build a partial record section,
  3283     "extend" to promote a fixed record to a record scheme, and
  3284     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3285     declared as simp by default;
  3286   - shared operations ("more", "fields", etc.) now need to be always
  3287     qualified) --- potential INCOMPATIBILITY;
  3288   - removed "make_scheme" operations (use "make" with "extend") --
  3289     INCOMPATIBILITY;
  3290   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3291   - provides cases/induct rules for use with corresponding Isar
  3292     methods (for concrete records, record schemes, concrete more
  3293     parts, and schematic more parts -- in that order);
  3294   - internal definitions directly based on a light-weight abstract
  3295     theory of product types over typedef rather than datatype;
  3296 
  3297 * HOL: generic code generator for generating executable ML code from
  3298 specifications; specific support for HOL constructs such as inductive
  3299 datatypes and sets, as well as recursive functions; can be invoked
  3300 via 'generate_code' theory section;
  3301 
  3302 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3303 
  3304 * HOL: consolidated and renamed several theories.  In particular:
  3305         Ord.thy has been absorbed into HOL.thy
  3306         String.thy has been absorbed into List.thy
  3307 
  3308 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3309 (beware of argument permutation!);
  3310 
  3311 * HOL: linorder_less_split superseded by linorder_cases;
  3312 
  3313 * HOL/List: "nodups" renamed to "distinct";
  3314 
  3315 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3316 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3317   - Ex_def has changed, now need to use some_eq_ex
  3318 
  3319 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3320 in this (rare) case use:
  3321 
  3322   delSWrapper "split_all_tac"
  3323   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3324 
  3325 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3326 MAY FAIL;
  3327 
  3328 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3329 Isabelle's type classes, ^ on functions and relations has too general
  3330 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3331 necessary to attach explicit type constraints;
  3332 
  3333 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3334 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3335 renamed accordingly (eg "compI" -> "rel_compI").
  3336 
  3337 * HOL: syntax translations now work properly with numerals and records
  3338 expressions;
  3339 
  3340 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3341 of "lam" -- INCOMPATIBILITY;
  3342 
  3343 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3344 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3345 renamed "Product_Type.unit";
  3346 
  3347 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3348 
  3349 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3350 the "cases" method);
  3351 
  3352 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3353 Florian Kammller);
  3354 
  3355 * HOL/IMP: updated and converted to new-style theory format; several
  3356 parts turned into readable document, with proper Isar proof texts and
  3357 some explanations (by Gerwin Klein);
  3358 
  3359 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3360 
  3361 * HOL-Hyperreal is now a logic image;
  3362 
  3363 
  3364 *** HOLCF ***
  3365 
  3366 * Isar: consts/constdefs supports mixfix syntax for continuous
  3367 operations;
  3368 
  3369 * Isar: domain package adapted to new-style theory format, e.g. see
  3370 HOLCF/ex/Dnat.thy;
  3371 
  3372 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3373 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3374 lift.induct_tac, always use UU instead of Undef;
  3375 
  3376 * HOLCF/IMP: updated and converted to new-style theory;
  3377 
  3378 
  3379 *** ZF ***
  3380 
  3381 * Isar: proper integration of logic-specific tools and packages,
  3382 including theory commands '(co)inductive', '(co)datatype',
  3383 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3384 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3385 
  3386 * theory Main no longer includes AC; for the Axiom of Choice, base
  3387 your theory on Main_ZFC;
  3388 
  3389 * the integer library now covers quotients and remainders, with many
  3390 laws relating division to addition, multiplication, etc.;
  3391 
  3392 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3393 typeless version of the formalism;
  3394 
  3395 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3396 format;
  3397 
  3398 * ZF/Induct: new directory for examples of inductive definitions,
  3399 including theory Multiset for multiset orderings; converted to
  3400 new-style theory format;
  3401 
  3402 * ZF: many new theorems about lists, ordinals, etc.;
  3403 
  3404 
  3405 *** General ***
  3406 
  3407 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3408 variable proof controls level of detail: 0 = no proofs (only oracle
  3409 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3410 also ref manual for further ML interfaces;
  3411 
  3412 * Pure/axclass: removed obsolete ML interface
  3413 goal_subclass/goal_arity;
  3414 
  3415 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3416 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3417 separate tokens, so expressions involving minus need to be spaced
  3418 properly;
  3419 
  3420 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3421 rather than "infixl" or "infixr";
  3422 
  3423 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3424 sort constraint specifications in type inference; e.g. "x::_::foo"
  3425 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3426 type variable);
  3427 
  3428 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3429 control output of nested => (types); the default behavior is
  3430 "type_brackets";
  3431 
  3432 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3433 tokens into AST constants;
  3434 
  3435 * Pure/syntax: prefer later declarations of translations and print
  3436 translation functions; potential INCOMPATIBILITY: need to reverse
  3437 multiple declarations for same syntax element constant;
  3438 
  3439 * Pure/show_hyps reset by default (in accordance to existing Isar
  3440 practice);
  3441 
  3442 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3443 addSafter;
  3444 
  3445 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3446 as well;
  3447 
  3448 * system: tested support for MacOS X; should be able to get Isabelle +
  3449 Proof General to work in a plain Terminal after installing Poly/ML
  3450 (e.g. from the Isabelle distribution area) and GNU bash alone
  3451 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3452 support requires further installations, e.g. from
  3453 http://fink.sourceforge.net/);
  3454 
  3455 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3456 
  3457 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3458 of 40 MB), cf. ML_OPTIONS;
  3459 
  3460 * system: Proof General keywords specification is now part of the
  3461 Isabelle distribution (see etc/isar-keywords.el);
  3462 
  3463 * system: support for persistent Proof General sessions (refrain from
  3464 outdating all loaded theories on startup); user may create writable
  3465 logic images like this: ``isabelle -q HOL Test'';
  3466 
  3467 * system: smart selection of Isabelle process versus Isabelle
  3468 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3469 run both "isabelle" and "Isabelle" even if file names are badly
  3470 damaged (executable inspects the case of the first letter of its own
  3471 name); added separate "isabelle-process" and "isabelle-interface";
  3472 
  3473 * system: refrain from any attempt at filtering input streams; no
  3474 longer support ``8bit'' encoding of old isabelle font, instead proper
  3475 iso-latin characters may now be used; the related isatools
  3476 "symbolinput" and "nonascii" have disappeared as well;
  3477 
  3478 * system: removed old "xterm" interface (the print modes "xterm" and
  3479 "xterm_color" are still available for direct use in a suitable
  3480 terminal);
  3481 
  3482 
  3483 
  3484 New in Isabelle99-2 (February 2001)
  3485 -----------------------------------
  3486 
  3487 *** Overview of INCOMPATIBILITIES ***
  3488 
  3489 * HOL: please note that theories in the Library and elsewhere often use the
  3490 new-style (Isar) format; to refer to their theorems in an ML script you must
  3491 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3492 
  3493 * HOL: inductive package no longer splits induction rule aggressively,
  3494 but only as far as specified by the introductions given; the old
  3495 format may be recovered via ML function complete_split_rule or attribute
  3496 'split_rule (complete)';
  3497 
  3498 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3499 gfp_Tarski to gfp_unfold;
  3500 
  3501 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3502 
  3503 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3504 relation); infix "^^" has been renamed "``"; infix "``" has been
  3505 renamed "`"; "univalent" has been renamed "single_valued";
  3506 
  3507 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3508 operation;
  3509 
  3510 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3511 
  3512 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3513 
  3514 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3515 consequence, it is no longer monotonic wrt. the local goal context
  3516 (which is now passed through the inductive cases);
  3517 
  3518 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3519 \<gg> to \<ggreater>;
  3520 
  3521 
  3522 *** Document preparation ***
  3523 
  3524 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3525 available: are "it" for near math-mode best-style output, "sl" for
  3526 slanted text style, and "tt" for plain type-writer; if no
  3527 \isabellestyle command is given, output is according to slanted
  3528 type-writer);
  3529 
  3530 * support sub/super scripts (for single symbols only), input syntax is
  3531 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3532 
  3533 * some more standard symbols; see Appendix A of the system manual for
  3534 the complete list of symbols defined in isabellesym.sty;
  3535 
  3536 * improved isabelle style files; more abstract symbol implementation
  3537 (should now use \isamath{...} and \isatext{...} in custom symbol
  3538 definitions);
  3539 
  3540 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3541 state; Note that presentation of goal states does not conform to
  3542 actual human-readable proof documents.  Please do not include goal
  3543 states into document output unless you really know what you are doing!
  3544 
  3545 * proper indentation of antiquoted output with proportional LaTeX
  3546 fonts;
  3547 
  3548 * no_document ML operator temporarily disables LaTeX document
  3549 generation;
  3550 
  3551 * isatool unsymbolize tunes sources for plain ASCII communication;
  3552 
  3553 
  3554 *** Isar ***
  3555 
  3556 * Pure: Isar now suffers initial goal statements to contain unbound
  3557 schematic variables (this does not conform to actual readable proof
  3558 documents, due to unpredictable outcome and non-compositional proof
  3559 checking); users who know what they are doing may use schematic goals
  3560 for Prolog-style synthesis of proven results;
  3561 
  3562 * Pure: assumption method (an implicit finishing) now handles actual
  3563 rules as well;
  3564 
  3565 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3566 initial goal, declare "that" only as Pure intro (only for single
  3567 steps); the "that" rule assumption may now be involved in implicit
  3568 finishing, thus ".." becomes a feasible for trivial obtains;
  3569 
  3570 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3571 instance proofs may be performed by "..";
  3572 
  3573 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3574 statements as well;
  3575 
  3576 * Pure: more robust selection of calculational rules;
  3577 
  3578 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3579 rule (as well as the assumption rule);
  3580 
  3581 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3582 lemmas, using the graph browser tool;
  3583 
  3584 * Pure: predict failure of "show" in interactive mode;
  3585 
  3586 * Pure: 'thms_containing' now takes actual terms as arguments;
  3587 
  3588 * HOL: improved method 'induct' --- now handles non-atomic goals
  3589 (potential INCOMPATIBILITY); tuned error handling;
  3590 
  3591 * HOL: cases and induct rules now provide explicit hints about the
  3592 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3593 any remaining facts are inserted into the goal verbatim;
  3594 
  3595 * HOL: local contexts (aka cases) may now contain term bindings as
  3596 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3597 the result to be shown in each case;
  3598 
  3599 * HOL: added 'recdef_tc' command;
  3600 
  3601 * isatool convert assists in eliminating legacy ML scripts;
  3602 
  3603 
  3604 *** HOL ***
  3605 
  3606 * HOL/Library: a collection of generic theories to be used together
  3607 with main HOL; the theory loader path already includes this directory
  3608 by default; the following existing theories have been moved here:
  3609 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3610 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3611 
  3612 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3613 modelling and verification task performed in Isabelle/HOL +
  3614 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3615 
  3616 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3617 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3618 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3619 'domain', this makes the theory consistent with mathematical
  3620 literature;
  3621 
  3622 * HOL basics: added overloaded operations "inverse" and "divide"
  3623 (infix "/"), syntax for generic "abs" operation, generic summation
  3624 operator \<Sum>;
  3625 
  3626 * HOL/typedef: simplified package, provide more useful rules (see also
  3627 HOL/subset.thy);
  3628 
  3629 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3630 now expressed as a proper nested rule (old-style tactic scripts may
  3631 require atomize_strip_tac to cope with non-atomic premises);
  3632 
  3633 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3634 to "split_conv" (old name still available for compatibility);
  3635 
  3636 * HOL: improved concrete syntax for strings (e.g. allows translation
  3637 rules with string literals);
  3638 
  3639 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3640  and Fleuriot's mechanization of analysis, including the transcendental
  3641  functions for the reals;
  3642 
  3643 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3644 
  3645 
  3646 *** CTT ***
  3647 
  3648 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3649 "lam" is displayed as TWO lambda-symbols
  3650 
  3651 * CTT: theory Main now available, containing everything (that is, Bool
  3652 and Arith);
  3653 
  3654 
  3655 *** General ***
  3656 
  3657 * Pure: the Simplifier has been implemented properly as a derived rule
  3658 outside of the actual kernel (at last!); the overall performance
  3659 penalty in practical applications is about 50%, while reliability of
  3660 the Isabelle inference kernel has been greatly improved;
  3661 
  3662 * print modes "brackets" and "no_brackets" control output of nested =>
  3663 (types) and ==> (props); the default behaviour is "brackets";
  3664 
  3665 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3666 as assumptions as well;
  3667 
  3668 * system: support Poly/ML 4.0;
  3669 
  3670 * system: isatool install handles KDE version 1 or 2;
  3671 
  3672 
  3673 
  3674 New in Isabelle99-1 (October 2000)
  3675 ----------------------------------
  3676 
  3677 *** Overview of INCOMPATIBILITIES ***
  3678 
  3679 * HOL: simplification of natural numbers is much changed; to partly
  3680 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3681 issue the following ML commands:
  3682 
  3683   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3684   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3685 
  3686 * HOL: simplification no longer dives into case-expressions; this is
  3687 controlled by "t.weak_case_cong" for each datatype t;
  3688 
  3689 * HOL: nat_less_induct renamed to less_induct;
  3690 
  3691 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3692 fixsome to patch .thy and .ML sources automatically;
  3693 
  3694   select_equality  -> some_equality
  3695   select_eq_Ex     -> some_eq_ex
  3696   selectI2EX       -> someI2_ex
  3697   selectI2         -> someI2
  3698   selectI          -> someI
  3699   select1_equality -> some1_equality
  3700   Eps_sym_eq       -> some_sym_eq_trivial
  3701   Eps_eq           -> some_eq_trivial
  3702 
  3703 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3704 
  3705 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3706 instead);
  3707 
  3708 * HOL: the recursion equations generated by 'recdef' are now called
  3709 f.simps instead of f.rules;
  3710 
  3711 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3712 
  3713 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3714 sometimes be needed;
  3715 
  3716 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3717 
  3718 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3719 
  3720 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3721 product is now "<*>" instead of "Times"; the lexicographic product is
  3722 now "<*lex*>" instead of "**";
  3723 
  3724 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3725 of main HOL, but was unused); better use HOL's datatype package;
  3726 
  3727 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3728 the old syntax may be recovered as follows:
  3729 
  3730   syntax (symbols)
  3731     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3732       (infixl "\\<oplus>" 100)
  3733 
  3734 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3735 
  3736 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3737 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3738 internally;
  3739 
  3740 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3741 changed from A/r to A//r;
  3742 
  3743 * ZF: new treatment of arithmetic (nat & int) may break some old
  3744 proofs;
  3745 
  3746 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3747 rulify -> rule_format, elimify -> elim_format, ...);
  3748 
  3749 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3750 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3751 should have to change intro!! to intro? only); replaced "delrule" by
  3752 "rule del";
  3753 
  3754 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3755 
  3756 * Provers: strengthened force_tac by using new first_best_tac;
  3757 
  3758 * LaTeX document preparation: several changes of isabelle.sty (see
  3759 lib/texinputs);
  3760 
  3761 
  3762 *** Document preparation ***
  3763 
  3764 * formal comments (text blocks etc.) in new-style theories may now
  3765 contain antiquotations of thm/prop/term/typ/text to be presented
  3766 according to latex print mode; concrete syntax is like this:
  3767 @{term[show_types] "f(x) = a + x"};
  3768 
  3769 * isatool mkdir provides easy setup of Isabelle session directories,
  3770 including proper document sources;
  3771 
  3772 * generated LaTeX sources are now deleted after successful run
  3773 (isatool document -c); may retain a copy somewhere else via -D option
  3774 of isatool usedir;
  3775 
  3776 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3777 style files, achieving self-contained LaTeX sources and simplifying
  3778 LaTeX debugging;
  3779 
  3780 * old-style theories now produce (crude) LaTeX output as well;
  3781 
  3782 * browser info session directories are now self-contained (may be put
  3783 on WWW server seperately); improved graphs of nested sessions; removed
  3784 graph for 'all sessions';
  3785 
  3786 * several improvements in isabelle style files; \isabellestyle{it}
  3787 produces fake math mode output; \isamarkupheader is now \section by
  3788 default; see lib/texinputs/isabelle.sty etc.;
  3789 
  3790 
  3791 *** Isar ***
  3792 
  3793 * Isar/Pure: local results and corresponding term bindings are now
  3794 subject to Hindley-Milner polymorphism (similar to ML); this
  3795 accommodates incremental type-inference very nicely;
  3796 
  3797 * Isar/Pure: new derived language element 'obtain' supports
  3798 generalized existence reasoning;
  3799 
  3800 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3801 support accumulation of results, without applying any rules yet;
  3802 useful to collect intermediate results without explicit name
  3803 references, and for use with transitivity rules with more than 2
  3804 premises;
  3805 
  3806 * Isar/Pure: scalable support for case-analysis type proofs: new
  3807 'case' language element refers to local contexts symbolically, as
  3808 produced by certain proof methods; internally, case names are attached
  3809 to theorems as "tags";
  3810 
  3811 * Isar/Pure: theory command 'hide' removes declarations from
  3812 class/type/const name spaces;
  3813 
  3814 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3815 indicate potential overloading;
  3816 
  3817 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3818 
  3819 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3820 "{a,b,c}" instead of {a,b,c};
  3821 
  3822 * Isar/Pure now provides its own version of intro/elim/dest
  3823 attributes; useful for building new logics, but beware of confusion
  3824 with the version in Provers/classical;
  3825 
  3826 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3827 case name 'antecedent';
  3828 
  3829 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3830 to the current context is now done automatically);
  3831 
  3832 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3833 for definining proof methods in ML;
  3834 
  3835 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3836 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3837 most cases, one should have to change intro!! to intro? only);
  3838 replaced "delrule" by "rule del";
  3839 
  3840 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3841 'symmetric' attribute (the latter supercedes [RS sym]);
  3842 
  3843 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3844 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3845 well (including splits);
  3846 
  3847 * Isar/Provers: Simplifier and Classical methods now support all kind
  3848 of modifiers used in the past, including 'cong', 'iff', etc.
  3849 
  3850 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3851 of Simplifier and Classical reasoner);
  3852 
  3853 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3854 now support named cases; major packages (inductive, datatype, primrec,
  3855 recdef) support case names and properly name parameters;
  3856 
  3857 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3858 monotonicity conditions are extracted to be proven at end of
  3859 calculations;
  3860 
  3861 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3862 method anyway;
  3863 
  3864 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3865 split_if split_if_asm; datatype package provides theorems foo.splits =
  3866 foo.split foo.split_asm for each datatype;
  3867 
  3868 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3869 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3870 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3871 use "(cases (simplified))" method in proper proof texts);
  3872 
  3873 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3874 
  3875 * Isar: names of theorems etc. may be natural numbers as well;
  3876 
  3877 * Isar: 'pr' command: optional arguments for goals_limit and
  3878 ProofContext.prems_limit; no longer prints theory contexts, but only
  3879 proof states;
  3880 
  3881 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3882 additional print modes to be specified; e.g. "pr(latex)" will print
  3883 proof state according to the Isabelle LaTeX style;
  3884 
  3885 * Isar: improved support for emulating tactic scripts, including proof
  3886 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3887 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3888 (for HOL datatypes);
  3889 
  3890 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3891 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3892 'proof method scripts' have to be in depth-first order;
  3893 
  3894 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3895 
  3896 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3897 should instead use individual commands for printing items
  3898 (print_commands, print_methods etc.);
  3899 
  3900 * Isar: added 'nothing' --- the empty list of theorems;
  3901 
  3902 
  3903 *** HOL ***
  3904 
  3905 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3906 corresponding virtual machine and a specification of its bytecode
  3907 verifier and a lightweight bytecode verifier, including proofs of
  3908 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3909 Cornelia Pusch (see also the homepage of project Bali at
  3910 http://isabelle.in.tum.de/Bali/);
  3911 
  3912 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3913 Clemens Ballarin;
  3914 
  3915 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3916 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3917 Rasmussen;
  3918 
  3919 * HOL/Lattice: fundamental concepts of lattice theory and order
  3920 structures, including duals, properties of bounds versus algebraic
  3921 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3922 Theorem for complete lattices etc.; may also serve as a demonstration
  3923 for abstract algebraic reasoning using axiomatic type classes, and
  3924 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3925 
  3926 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3927 von Oheimb;
  3928 
  3929 * HOL/IMPP: extension of IMP with local variables and mutually
  3930 recursive procedures, by David von Oheimb;
  3931 
  3932 * HOL/Lambda: converted into new-style theory and document;
  3933 
  3934 * HOL/ex/Multiquote: example of multiple nested quotations and
  3935 anti-quotations -- basically a generalized version of de-Bruijn
  3936 representation; very useful in avoiding lifting of operations;
  3937 
  3938 * HOL/record: added general record equality rule to simpset; fixed
  3939 select-update simplification procedure to handle extended records as
  3940 well; admit "r" as field name;
  3941 
  3942 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3943 other numeric types and also as the identity of groups, rings, etc.;
  3944 
  3945 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3946 Types nat and int belong to this axclass;
  3947 
  3948 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3949    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3950    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3951   two terms #m*u and #n*u are replaced by #(m+n)*u
  3952     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3953   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3954     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3955 
  3956 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3957 powerful prover for predicate logic but knows nothing of clasets; see
  3958 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3959 
  3960 * HOL: new version of "case_tac" subsumes both boolean case split and
  3961 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3962 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3963 
  3964 * HOL: simplification no longer dives into case-expressions: only the
  3965 selector expression is simplified, but not the remaining arms; to
  3966 enable full simplification of case-expressions for datatype t, you may
  3967 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3968 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3969 
  3970 * HOL/recdef: the recursion equations generated by 'recdef' for
  3971 function 'f' are now called f.simps instead of f.rules; if all
  3972 termination conditions are proved automatically, these simplification
  3973 rules are added to the simpset, as in primrec; rules may be named
  3974 individually as well, resulting in a separate list of theorems for
  3975 each equation;
  3976 
  3977 * HOL/While is a new theory that provides a while-combinator. It
  3978 permits the definition of tail-recursive functions without the
  3979 provision of a termination measure. The latter is necessary once the
  3980 invariant proof rule for while is applied.
  3981 
  3982 * HOL: new (overloaded) notation for the set of elements below/above
  3983 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3984 
  3985 * HOL: theorems impI, allI, ballI bound as "strip";
  3986 
  3987 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3988 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3989 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3990 
  3991 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3992 
  3993 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3994 main HOL, but was unused);
  3995 
  3996 * HOL: fewer consts declared as global (e.g. have to refer to
  3997 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3998 
  3999 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4000 in case of overlap with user translations (e.g. judgements over
  4001 tuples); (note that the underlying logical represenation is still
  4002 bogus);
  4003 
  4004 
  4005 *** ZF ***
  4006 
  4007 * ZF: simplification automatically cancels common terms in arithmetic
  4008 expressions over nat and int;
  4009 
  4010 * ZF: new treatment of nat to minimize type-checking: all operators
  4011 coerce their operands to a natural number using the function natify,
  4012 making the algebraic laws unconditional;
  4013 
  4014 * ZF: as above, for int: operators coerce their operands to an integer
  4015 using the function intify;
  4016 
  4017 * ZF: the integer library now contains many of the usual laws for the
  4018 orderings, including $<=, and monotonicity laws for $+ and $*;
  4019 
  4020 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4021 simplification;
  4022 
  4023 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4024 to the simplifier and classical reasoner simultaneously;
  4025 
  4026 
  4027 *** General ***
  4028 
  4029 * Provers: blast_tac now handles actual object-logic rules as
  4030 assumptions; note that auto_tac uses blast_tac internally as well;
  4031 
  4032 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4033 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4034 
  4035 * Provers: delrules now handles destruct rules as well (no longer need
  4036 explicit make_elim);
  4037 
  4038 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4039   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4040 use instead the strong form,
  4041   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4042 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4043 from destruct-rules;
  4044 
  4045 * Provers: Simplifier.easy_setup provides a fast path to basic
  4046 Simplifier setup for new object-logics;
  4047 
  4048 * Pure: AST translation rules no longer require constant head on LHS;
  4049 
  4050 * Pure: improved name spaces: ambiguous output is qualified; support
  4051 for hiding of names;
  4052 
  4053 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4054 XSYMBOL_HOME; no longer need to do manual configuration in most
  4055 situations;
  4056 
  4057 * system: compression of ML heaps images may now be controlled via -c
  4058 option of isabelle and isatool usedir (currently only observed by
  4059 Poly/ML);
  4060 
  4061 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4062 useful for remote X11);
  4063 
  4064 * system: provide TAGS file for Isabelle sources;
  4065 
  4066 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4067 order;
  4068 
  4069 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4070 timing flag supersedes proof_timing and Toplevel.trace;
  4071 
  4072 * ML: new combinators |>> and |>>> for incremental transformations
  4073 with secondary results (e.g. certain theory extensions):
  4074 
  4075 * ML: PureThy.add_defs gets additional argument to indicate potential
  4076 overloading (usually false);
  4077 
  4078 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4079 results;
  4080 
  4081 
  4082 
  4083 New in Isabelle99 (October 1999)
  4084 --------------------------------
  4085 
  4086 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4087 
  4088 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4089 are no longer simplified.  (This allows the simplifier to unfold recursive
  4090 functional programs.)  To restore the old behaviour, declare
  4091 
  4092     Delcongs [if_weak_cong];
  4093 
  4094 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4095 complement;
  4096 
  4097 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4098 
  4099 * HOL/datatype: mutual_induct_tac no longer exists --
  4100   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4101 
  4102 * HOL/typedef: fixed type inference for representing set; type
  4103 arguments now have to occur explicitly on the rhs as type constraints;
  4104 
  4105 * ZF: The con_defs part of an inductive definition may no longer refer
  4106 to constants declared in the same theory;
  4107 
  4108 * HOL, ZF: the function mk_cases, generated by the inductive
  4109 definition package, has lost an argument.  To simplify its result, it
  4110 uses the default simpset instead of a supplied list of theorems.
  4111 
  4112 * HOL/List: the constructors of type list are now Nil and Cons;
  4113 
  4114 * Simplifier: the type of the infix ML functions
  4115         setSSolver addSSolver setSolver addSolver
  4116 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4117 for packaging solvers. A solver is created via
  4118         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4119 where the string argument is only a comment.
  4120 
  4121 
  4122 *** Proof tools ***
  4123 
  4124 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4125 decision procedure for linear arithmetic. Currently it is used for
  4126 types `nat', `int', and `real' in HOL (see below); it can, should and
  4127 will be instantiated for other types and logics as well.
  4128 
  4129 * The simplifier now accepts rewrite rules with flexible heads, eg
  4130      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4131   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4132   matching.
  4133 
  4134 
  4135 *** General ***
  4136 
  4137 * New Isabelle/Isar subsystem provides an alternative to traditional
  4138 tactical theorem proving; together with the ProofGeneral/isar user
  4139 interface it offers an interactive environment for developing human
  4140 readable proof documents (Isar == Intelligible semi-automated
  4141 reasoning); for further information see isatool doc isar-ref,
  4142 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4143 
  4144 * improved and simplified presentation of theories: better HTML markup
  4145 (including colors), graph views in several sizes; isatool usedir now
  4146 provides a proper interface for user theories (via -P option); actual
  4147 document preparation based on (PDF)LaTeX is available as well (for
  4148 new-style theories only); see isatool doc system for more information;
  4149 
  4150 * native support for Proof General, both for classic Isabelle and
  4151 Isabelle/Isar;
  4152 
  4153 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4154 using the graph browser tool;
  4155 
  4156 * Isabelle manuals now also available as PDF;
  4157 
  4158 * theory loader rewritten from scratch (may not be fully
  4159 bug-compatible); old loadpath variable has been replaced by show_path,
  4160 add_path, del_path, reset_path functions; new operations such as
  4161 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4162 isatool doc ref);
  4163 
  4164 * improved isatool install: option -k creates KDE application icon,
  4165 option -p DIR installs standalone binaries;
  4166 
  4167 * added ML_PLATFORM setting (useful for cross-platform installations);
  4168 more robust handling of platform specific ML images for SML/NJ;
  4169 
  4170 * the settings environment is now statically scoped, i.e. it is never
  4171 created again in sub-processes invoked from isabelle, isatool, or
  4172 Isabelle;
  4173 
  4174 * path element specification '~~' refers to '$ISABELLE_HOME';
  4175 
  4176 * in locales, the "assumes" and "defines" parts may be omitted if
  4177 empty;
  4178 
  4179 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4180 long arrows);
  4181 
  4182 * new print_mode "HTML";
  4183 
  4184 * new flag show_tags controls display of tags of theorems (which are
  4185 basically just comments that may be attached by some tools);
  4186 
  4187 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4188 mode and goal output format:
  4189 
  4190 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4191 244c244
  4192 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4193 ---
  4194 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4195 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4196 181c181
  4197 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4198 ---
  4199 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4200 
  4201 * function bind_thms stores lists of theorems (cf. bind_thm);
  4202 
  4203 * new shorthand tactics ftac, eatac, datac, fatac;
  4204 
  4205 * qed (and friends) now accept "" as result name; in that case the
  4206 theorem is not stored, but proper checks and presentation of the
  4207 result still apply;
  4208 
  4209 * theorem database now also indexes constants "Trueprop", "all",
  4210 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4211 
  4212 
  4213 *** HOL ***
  4214 
  4215 ** HOL arithmetic **
  4216 
  4217 * There are now decision procedures for linear arithmetic over nat and
  4218 int:
  4219 
  4220 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4221 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4222 are treated as atomic; subformulae not involving type `nat' or `int'
  4223 are ignored; quantified subformulae are ignored unless they are
  4224 positive universal or negative existential. The tactic has to be
  4225 invoked by hand and can be a little bit slow. In particular, the
  4226 running time is exponential in the number of occurrences of `min' and
  4227 `max', and `-' on `nat'.
  4228 
  4229 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4230 (negated) (in)equalities among the premises and the conclusion into
  4231 account (i.e. no compound formulae) and does not know about `min' and
  4232 `max', and `-' on `nat'. It is fast and is used automatically by the
  4233 simplifier.
  4234 
  4235 NB: At the moment, these decision procedures do not cope with mixed
  4236 nat/int formulae where the two parts interact, such as `m < n ==>
  4237 int(m) < int(n)'.
  4238 
  4239 * HOL/Numeral provides a generic theory of numerals (encoded
  4240 efficiently as bit strings); setup for types nat/int/real is in place;
  4241 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4242 int, existing theories and proof scripts may require a few additional
  4243 type constraints;
  4244 
  4245 * integer division and remainder can now be performed on constant
  4246 arguments;
  4247 
  4248 * many properties of integer multiplication, division and remainder
  4249 are now available;
  4250 
  4251 * An interface to the Stanford Validity Checker (SVC) is available through the
  4252 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4253 are proved automatically.  SVC must be installed separately, and its results
  4254 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4255 invocation of the underlying oracle).  For SVC see
  4256   http://verify.stanford.edu/SVC
  4257 
  4258 * IsaMakefile: the HOL-Real target now builds an actual image;
  4259 
  4260 
  4261 ** HOL misc **
  4262 
  4263 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4264 (in Isabelle/Isar) -- by Gertrud Bauer;
  4265 
  4266 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4267 analysis for assembly languages with subtypes;
  4268 
  4269 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4270 -- avoids syntactic ambiguities and treats state, transition, and
  4271 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4272 changed syntax and (many) tactics;
  4273 
  4274 * HOL/inductive: Now also handles more general introduction rules such
  4275   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4276   theorems are now maintained within the theory (maintained via the
  4277   "mono" attribute);
  4278 
  4279 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4280   (using function types) such as
  4281 
  4282   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4283 
  4284 * HOL/record: record_simproc (part of the default simpset) takes care
  4285 of selectors applied to updated records; record_split_tac is no longer
  4286 part of the default claset; update_defs may now be removed from the
  4287 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4288 
  4289   claset_ref () := claset() addSWrapper record_split_wrapper;
  4290   Delsimprocs [record_simproc]
  4291 
  4292 * HOL/typedef: fixed type inference for representing set; type
  4293 arguments now have to occur explicitly on the rhs as type constraints;
  4294 
  4295 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4296 names rather than an ML expression;
  4297 
  4298 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4299 supplied later.  Program schemes can be defined, such as
  4300     "While B C s = (if B s then While B C (C s) else s)"
  4301 where the well-founded relation can be chosen after B and C have been given.
  4302 
  4303 * HOL/List: the constructors of type list are now Nil and Cons;
  4304 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4305 course, ML tools referring to List.list.op # etc. have to be adapted;
  4306 
  4307 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4308 disabled by default; run isabelle with option -m HOL to get back to
  4309 the original Gordon/HOL-style output;
  4310 
  4311 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4312 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4313 
  4314 * HOL basic syntax simplified (more orthogonal): all variants of
  4315 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4316 Eps operator is provided as well: "SOME x. P[x]";
  4317 
  4318 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4319 
  4320 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4321 thus available for user theories;
  4322 
  4323 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4324 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4325 time;
  4326 
  4327 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4328 several times and then mp;
  4329 
  4330 
  4331 *** LK ***
  4332 
  4333 * the notation <<...>> is now available as a notation for sequences of
  4334 formulas;
  4335 
  4336 * the simplifier is now installed
  4337 
  4338 * the axiom system has been generalized (thanks to Soren Heilmann)
  4339 
  4340 * the classical reasoner now has a default rule database
  4341 
  4342 
  4343 *** ZF ***
  4344 
  4345 * new primrec section allows primitive recursive functions to be given
  4346 directly (as in HOL) over datatypes and the natural numbers;
  4347 
  4348 * new tactics induct_tac and exhaust_tac for induction (or case
  4349 analysis) over datatypes and the natural numbers;
  4350 
  4351 * the datatype declaration of type T now defines the recursor T_rec;
  4352 
  4353 * simplification automatically does freeness reasoning for datatype
  4354 constructors;
  4355 
  4356 * automatic type-inference, with AddTCs command to insert new
  4357 type-checking rules;
  4358 
  4359 * datatype introduction rules are now added as Safe Introduction rules
  4360 to the claset;
  4361 
  4362 * the syntax "if P then x else y" is now available in addition to
  4363 if(P,x,y);
  4364 
  4365 
  4366 *** Internal programming interfaces ***
  4367 
  4368 * tuned simplifier trace output; new flag debug_simp;
  4369 
  4370 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4371 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4372 
  4373 * AxClass.axclass_tac lost the theory argument;
  4374 
  4375 * tuned current_goals_markers semantics: begin / end goal avoids
  4376 printing empty lines;
  4377 
  4378 * removed prs and prs_fn hook, which was broken because it did not
  4379 include \n in its semantics, forcing writeln to add one
  4380 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4381 string -> unit if you really want to output text without newline;
  4382 
  4383 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4384 plain output, interface builders may have to enable 'isabelle_font'
  4385 mode to get Isabelle font glyphs as before;
  4386 
  4387 * refined token_translation interface; INCOMPATIBILITY: output length
  4388 now of type real instead of int;
  4389 
  4390 * theory loader actions may be traced via new ThyInfo.add_hook
  4391 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4392 your own database of information attached to *whole* theories -- as
  4393 opposed to intra-theory data slots offered via TheoryDataFun;
  4394 
  4395 * proper handling of dangling sort hypotheses (at last!);
  4396 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4397 extra sort hypotheses that can be witnessed from the type signature;
  4398 the force_strip_shyps flag is gone, any remaining shyps are simply
  4399 left in the theorem (with a warning issued by strip_shyps_warning);
  4400 
  4401 
  4402 
  4403 New in Isabelle98-1 (October 1998)
  4404 ----------------------------------
  4405 
  4406 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4407 
  4408 * several changes of automated proof tools;
  4409 
  4410 * HOL: major changes to the inductive and datatype packages, including
  4411 some minor incompatibilities of theory syntax;
  4412 
  4413 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4414 called `inj_on';
  4415 
  4416 * HOL: removed duplicate thms in Arith:
  4417   less_imp_add_less  should be replaced by  trans_less_add1
  4418   le_imp_add_le      should be replaced by  trans_le_add1
  4419 
  4420 * HOL: unary minus is now overloaded (new type constraints may be
  4421 required);
  4422 
  4423 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4424 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4425 now taken as an integer constant.
  4426 
  4427 * Pure: ML function 'theory_of' renamed to 'theory';
  4428 
  4429 
  4430 *** Proof tools ***
  4431 
  4432 * Simplifier:
  4433   1. Asm_full_simp_tac is now more aggressive.
  4434      1. It will sometimes reorient premises if that increases their power to
  4435         simplify.
  4436      2. It does no longer proceed strictly from left to right but may also
  4437         rotate premises to achieve further simplification.
  4438      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4439      old Asm_full_simp_tac in that it does not rotate premises.
  4440   2. The simplifier now knows a little bit about nat-arithmetic.
  4441 
  4442 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4443 allows for selected deletion of wrappers, by introduction of names for
  4444 wrapper functionals.  This implies that addbefore, addSbefore,
  4445 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4446 and that adding two tactics with the same name overwrites the first
  4447 one (emitting a warning).
  4448   type wrapper = (int -> tactic) -> (int -> tactic)
  4449   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4450   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4451   delWrapper, delSWrapper: claset *  string            -> claset
  4452   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4453 
  4454 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4455 semantics; addbefore now affects only the unsafe part of step_tac
  4456 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4457 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4458 by Force_tac;
  4459 
  4460 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4461 compWrapper; added safe wrapper (and access functions for it);
  4462 
  4463 * HOL/split_all_tac is now much faster and fails if there is nothing
  4464 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4465 and the names of the automatically generated variables have changed.
  4466 split_all_tac has moved within claset() from unsafe wrappers to safe
  4467 wrappers, which means that !!-bound variables are split much more
  4468 aggressively, and safe_tac and clarify_tac now split such variables.
  4469 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4470 Note: the same holds for record_split_tac, which does the job of
  4471 split_all_tac for record fields.
  4472 
  4473 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4474 permanently to the default simpset using Addsplits just like
  4475 Addsimps. They can be removed via Delsplits just like
  4476 Delsimps. Lower-case versions are also available.
  4477 
  4478 * HOL/Simplifier: The rule split_if is now part of the default
  4479 simpset. This means that the simplifier will eliminate all occurrences
  4480 of if-then-else in the conclusion of a goal. To prevent this, you can
  4481 either remove split_if completely from the default simpset by
  4482 `Delsplits [split_if]' or remove it in a specific call of the
  4483 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4484 other case splitting rules to/from the default simpset: every datatype
  4485 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4486 t is the name of the datatype).
  4487 
  4488 * Classical reasoner / Simplifier combination: new force_tac (and
  4489 derivatives Force_tac, force) combines rewriting and classical
  4490 reasoning (and whatever other tools) similarly to auto_tac, but is
  4491 aimed to solve the given subgoal completely.
  4492 
  4493 
  4494 *** General ***
  4495 
  4496 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4497 and `goalw': the theory is no longer needed as an explicit argument -
  4498 the current theory context is used; assumptions are no longer returned
  4499 at the ML-level unless one of them starts with ==> or !!; it is
  4500 recommended to convert to these new commands using isatool fixgoal
  4501 (backup your sources first!);
  4502 
  4503 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4504 the current theory context, and 'theory' to lookup stored theories;
  4505 
  4506 * new theory section 'locale' for declaring constants, assumptions and
  4507 definitions that have local scope;
  4508 
  4509 * new theory section 'nonterminals' for purely syntactic types;
  4510 
  4511 * new theory section 'setup' for generic ML setup functions
  4512 (e.g. package initialization);
  4513 
  4514 * the distribution now includes Isabelle icons: see
  4515 lib/logo/isabelle-{small,tiny}.xpm;
  4516 
  4517 * isatool install - install binaries with absolute references to
  4518 ISABELLE_HOME/bin;
  4519 
  4520 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4521 
  4522 * print mode 'emacs' reserved for Isamode;
  4523 
  4524 * support multiple print (ast) translations per constant name;
  4525 
  4526 * theorems involving oracles are now printed with a suffixed [!];
  4527 
  4528 
  4529 *** HOL ***
  4530 
  4531 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4532 
  4533 * HOL/inductive package reorganized and improved: now supports mutual
  4534 definitions such as
  4535 
  4536   inductive EVEN ODD
  4537     intrs
  4538       null "0 : EVEN"
  4539       oddI "n : EVEN ==> Suc n : ODD"
  4540       evenI "n : ODD ==> Suc n : EVEN"
  4541 
  4542 new theorem list "elims" contains an elimination rule for each of the
  4543 recursive sets; inductive definitions now handle disjunctive premises
  4544 correctly (also ZF);
  4545 
  4546 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4547 "mutual_induct" no longer exists - the induction rule is always
  4548 contained in "induct";
  4549 
  4550 
  4551 * HOL/datatype package re-implemented and greatly improved: now
  4552 supports mutually recursive datatypes such as
  4553 
  4554   datatype
  4555     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4556             | SUM ('a aexp) ('a aexp)
  4557             | DIFF ('a aexp) ('a aexp)
  4558             | NUM 'a
  4559   and
  4560     'a bexp = LESS ('a aexp) ('a aexp)
  4561             | AND ('a bexp) ('a bexp)
  4562             | OR ('a bexp) ('a bexp)
  4563 
  4564 as well as indirectly recursive datatypes such as
  4565 
  4566   datatype
  4567     ('a, 'b) term = Var 'a
  4568                   | App 'b ((('a, 'b) term) list)
  4569 
  4570 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4571 induction on mutually / indirectly recursive datatypes.
  4572 
  4573 Primrec equations are now stored in theory and can be accessed via
  4574 <function_name>.simps.
  4575 
  4576 INCOMPATIBILITIES:
  4577 
  4578   - Theories using datatypes must now have theory Datatype as an
  4579     ancestor.
  4580   - The specific <typename>.induct_tac no longer exists - use the
  4581     generic induct_tac instead.
  4582   - natE has been renamed to nat.exhaust - use exhaust_tac
  4583     instead of res_inst_tac ... natE. Note that the variable
  4584     names in nat.exhaust differ from the names in natE, this
  4585     may cause some "fragile" proofs to fail.
  4586   - The theorems split_<typename>_case and split_<typename>_case_asm
  4587     have been renamed to <typename>.split and <typename>.split_asm.
  4588   - Since default sorts of type variables are now handled correctly,
  4589     some datatype definitions may have to be annotated with explicit
  4590     sort constraints.
  4591   - Primrec definitions no longer require function name and type
  4592     of recursive argument.
  4593 
  4594 Consider using isatool fixdatatype to adapt your theories and proof
  4595 scripts to the new package (backup your sources first!).
  4596 
  4597 
  4598 * HOL/record package: considerably improved implementation; now
  4599 includes concrete syntax for record types, terms, updates; theorems
  4600 for surjective pairing and splitting !!-bound record variables; proof
  4601 support is as follows:
  4602 
  4603   1) standard conversions (selectors or updates applied to record
  4604 constructor terms) are part of the standard simpset;
  4605 
  4606   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4607 made part of standard simpset and claset via addIffs;
  4608 
  4609   3) a tactic for record field splitting (record_split_tac) is part of
  4610 the standard claset (addSWrapper);
  4611 
  4612 To get a better idea about these rules you may retrieve them via
  4613 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4614 the name of your record type.
  4615 
  4616 The split tactic 3) conceptually simplifies by the following rule:
  4617 
  4618   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4619 
  4620 Thus any record variable that is bound by meta-all will automatically
  4621 blow up into some record constructor term, consequently the
  4622 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4623 solve record problems automatically.
  4624 
  4625 
  4626 * reorganized the main HOL image: HOL/Integ and String loaded by
  4627 default; theory Main includes everything;
  4628 
  4629 * automatic simplification of integer sums and comparisons, using cancellation;
  4630 
  4631 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4632 
  4633 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4634 
  4635 * many new identities for unions, intersections, set difference, etc.;
  4636 
  4637 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4638 called split_if, split_split, split_sum_case and split_nat_case (to go
  4639 with add/delsplits);
  4640 
  4641 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4642 (?x::unit) = (); this is made part of the default simpset, which COULD
  4643 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4644 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4645 unit_abs_eta_conv is added in order to counter the effect of
  4646 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4647 %u.f();
  4648 
  4649 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4650 makes more sense);
  4651 
  4652 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4653   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4654   disjointness reasoning but breaking a few old proofs.
  4655 
  4656 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4657 to 'converse' from 'inverse' (for compatibility with ZF and some
  4658 literature);
  4659 
  4660 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4661 the well-founded relation;
  4662 
  4663 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4664     Compl A.  The "Compl" syntax remains available as input syntax for this
  4665     release ONLY.
  4666 
  4667 * HOL/Update: new theory of function updates:
  4668     f(a:=b) == %x. if x=a then b else f x
  4669 may also be iterated as in f(a:=b,c:=d,...);
  4670 
  4671 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4672 
  4673 * HOL/List:
  4674   - new function list_update written xs[i:=v] that updates the i-th
  4675     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4676   - new function `upt' written [i..j(] which generates the list
  4677     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4678     bound write [i..j], which is a shorthand for [i..j+1(].
  4679   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4680 
  4681 * HOL/Arith:
  4682   - removed 'pred' (predecessor) function;
  4683   - generalized some theorems about n-1;
  4684   - many new laws about "div" and "mod";
  4685   - new laws about greatest common divisors (see theory ex/Primes);
  4686 
  4687 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4688 instead of "inverse";
  4689 
  4690 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4691   of the multiset ordering;
  4692 
  4693 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4694   (not included by default);
  4695 
  4696 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4697 
  4698 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4699   programs, i.e. different program variables may have different types.
  4700 
  4701 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4702   [previously, this check worked only if the rewrite rule was unconditional]
  4703   Now rew can involve either definitions or equalities (either == or =).
  4704 
  4705 
  4706 *** ZF ***
  4707 
  4708 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4709   only the theorems proved on ZF.ML;
  4710 
  4711 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4712   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4713   disjointness reasoning but breaking a few old proofs.
  4714 
  4715 * ZF/Update: new theory of function updates
  4716     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4717   may also be iterated as in f(a:=b,c:=d,...);
  4718 
  4719 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4720 
  4721 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4722   [previously, this check worked only if the rewrite rule was unconditional]
  4723   Now rew can involve either definitions or equalities (either == or =).
  4724 
  4725 * case_tac provided for compatibility with HOL
  4726     (like the old excluded_middle_tac, but with subgoals swapped)
  4727 
  4728 
  4729 *** Internal programming interfaces ***
  4730 
  4731 * Pure: several new basic modules made available for general use, see
  4732 also src/Pure/README;
  4733 
  4734 * improved the theory data mechanism to support encapsulation (data
  4735 kind name replaced by private Object.kind, acting as authorization
  4736 key); new type-safe user interface via functor TheoryDataFun; generic
  4737 print_data function becomes basically useless;
  4738 
  4739 * removed global_names compatibility flag -- all theory declarations
  4740 are qualified by default;
  4741 
  4742 * module Pure/Syntax now offers quote / antiquote translation
  4743 functions (useful for Hoare logic etc. with implicit dependencies);
  4744 see HOL/ex/Antiquote for an example use;
  4745 
  4746 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4747 cterm -> thm;
  4748 
  4749 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4750 subgoal;
  4751 
  4752 * Display.print_goals function moved to Locale.print_goals;
  4753 
  4754 * standard print function for goals supports current_goals_markers
  4755 variable for marking begin of proof, end of proof, start of goal; the
  4756 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4757 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4758 for example;
  4759 
  4760 
  4761 
  4762 New in Isabelle98 (January 1998)
  4763 --------------------------------
  4764 
  4765 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4766 
  4767 * changed lexical syntax of terms / types: dots made part of long
  4768 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4769 
  4770 * simpset (and claset) reference variable replaced by functions
  4771 simpset / simpset_ref;
  4772 
  4773 * no longer supports theory aliases (via merge) and non-trivial
  4774 implicit merge of thms' signatures;
  4775 
  4776 * most internal names of constants changed due to qualified names;
  4777 
  4778 * changed Pure/Sequence interface (see Pure/seq.ML);
  4779 
  4780 
  4781 *** General Changes ***
  4782 
  4783 * hierachically structured name spaces (for consts, types, axms, thms
  4784 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4785 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4786 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4787 long_names for fully qualified output names; NOTE: ML programs
  4788 (special tactics, packages etc.) referring to internal names may have
  4789 to be adapted to cope with fully qualified names; in case of severe
  4790 backward campatibility problems try setting 'global_names' at compile
  4791 time to have enrything declared within a flat name space; one may also
  4792 fine tune name declarations in theories via the 'global' and 'local'
  4793 section;
  4794 
  4795 * reimplemented the implicit simpset and claset using the new anytype
  4796 data filed in signatures; references simpset:simpset ref etc. are
  4797 replaced by functions simpset:unit->simpset and
  4798 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4799 to patch your ML files accordingly;
  4800 
  4801 * HTML output now includes theory graph data for display with Java
  4802 applet or isatool browser; data generated automatically via isatool
  4803 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4804 
  4805 * defs may now be conditional; improved rewrite_goals_tac to handle
  4806 conditional equations;
  4807 
  4808 * defs now admits additional type arguments, using TYPE('a) syntax;
  4809 
  4810 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4811 creates a new theory node; implicit merge of thms' signatures is
  4812 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4813 transfer:theory->thm->thm in (rare) cases;
  4814 
  4815 * improved handling of draft signatures / theories; draft thms (and
  4816 ctyps, cterms) are automatically promoted to real ones;
  4817 
  4818 * slightly changed interfaces for oracles: admit many per theory, named
  4819 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4820 
  4821 * print_goals: optional output of const types (set show_consts and
  4822 show_types);
  4823 
  4824 * improved output of warnings (###) and errors (***);
  4825 
  4826 * subgoal_tac displays a warning if the new subgoal has type variables;
  4827 
  4828 * removed old README and Makefiles;
  4829 
  4830 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4831 
  4832 * removed obsolete init_pps and init_database;
  4833 
  4834 * deleted the obsolete tactical STATE, which was declared by
  4835     fun STATE tacfun st = tacfun st st;
  4836 
  4837 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4838 (which abbreviates $HOME);
  4839 
  4840 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4841 use isatool fixseq to adapt your ML programs (this works for fully
  4842 qualified references to the Sequence structure only!);
  4843 
  4844 * use_thy no longer requires writable current directory; it always
  4845 reloads .ML *and* .thy file, if either one is out of date;
  4846 
  4847 
  4848 *** Classical Reasoner ***
  4849 
  4850 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4851 tactics that use classical reasoning to simplify a subgoal without
  4852 splitting it into several subgoals;
  4853 
  4854 * Safe_tac: like safe_tac but uses the default claset;
  4855 
  4856 
  4857 *** Simplifier ***
  4858 
  4859 * added simplification meta rules:
  4860     (asm_)(full_)simplify: simpset -> thm -> thm;
  4861 
  4862 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4863 logics (again);
  4864 
  4865 * added prems argument to simplification procedures;
  4866 
  4867 * HOL, FOL, ZF: added infix function `addsplits':
  4868   instead of `<simpset> setloop (split_tac <thms>)'
  4869   you can simply write `<simpset> addsplits <thms>'
  4870 
  4871 
  4872 *** Syntax ***
  4873 
  4874 * TYPE('a) syntax for type reflection terms;
  4875 
  4876 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4877 
  4878 * pretty printer: changed order of mixfix annotation preference (again!);
  4879 
  4880 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4881 
  4882 
  4883 *** HOL ***
  4884 
  4885 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4886   with `addloop' of the simplifier to faciliate case splitting in premises.
  4887 
  4888 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4889 
  4890 * HOL/Auth: new protocol proofs including some for the Internet
  4891   protocol TLS;
  4892 
  4893 * HOL/Map: new theory of `maps' a la VDM;
  4894 
  4895 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4896 cancelling out common nat summands from =, <, <= (in)equalities, or
  4897 differences; simplification procedures nat_cancel_factor for
  4898 cancelling common factor from =, <, <= (in)equalities over natural
  4899 sums; nat_cancel contains both kinds of procedures, it is installed by
  4900 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4901 
  4902 * HOL/simplifier: terms of the form
  4903   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4904   are rewritten to
  4905   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4906   and those of the form
  4907   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4908   are rewritten to
  4909   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4910 
  4911 * HOL/datatype
  4912   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4913 
  4914   P(t_case f1 ... fn x) =
  4915      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4916         ...
  4917        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4918      )
  4919 
  4920   and a theorem `split_t_case_asm' of the form
  4921 
  4922   P(t_case f1 ... fn x) =
  4923     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4924         ...
  4925        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4926      )
  4927   which can be added to a simpset via `addsplits'. The existing theorems
  4928   expand_list_case and expand_option_case have been renamed to
  4929   split_list_case and split_option_case.
  4930 
  4931 * HOL/Arithmetic:
  4932   - `pred n' is automatically converted to `n-1'.
  4933     Users are strongly encouraged not to use `pred' any longer,
  4934     because it will disappear altogether at some point.
  4935   - Users are strongly encouraged to write "0 < n" rather than
  4936     "n ~= 0". Theorems and proof tools have been modified towards this
  4937     `standard'.
  4938 
  4939 * HOL/Lists:
  4940   the function "set_of_list" has been renamed "set" (and its theorems too);
  4941   the function "nth" now takes its arguments in the reverse order and
  4942   has acquired the infix notation "!" as in "xs!n".
  4943 
  4944 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4945 
  4946 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4947   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4948 
  4949 * HOL/record: extensible records with schematic structural subtyping
  4950 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4951 still lacks various theorems and concrete record syntax;
  4952 
  4953 
  4954 *** HOLCF ***
  4955 
  4956 * removed "axioms" and "generated by" sections;
  4957 
  4958 * replaced "ops" section by extended "consts" section, which is capable of
  4959   handling the continuous function space "->" directly;
  4960 
  4961 * domain package:
  4962   . proves theorems immediately and stores them in the theory,
  4963   . creates hierachical name space,
  4964   . now uses normal mixfix annotations (instead of cinfix...),
  4965   . minor changes to some names and values (for consistency),
  4966   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4967   . separator between mutual domain defs: changed "," to "and",
  4968   . improved handling of sort constraints;  now they have to
  4969     appear on the left-hand side of the equations only;
  4970 
  4971 * fixed LAM <x,y,zs>.b syntax;
  4972 
  4973 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4974 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4975 
  4976 
  4977 *** FOL and ZF ***
  4978 
  4979 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4980   with `addloop' of the simplifier to faciliate case splitting in premises.
  4981 
  4982 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4983 in HOL, they strip ALL and --> from proved theorems;
  4984 
  4985 
  4986 
  4987 New in Isabelle94-8 (May 1997)
  4988 ------------------------------
  4989 
  4990 *** General Changes ***
  4991 
  4992 * new utilities to build / run / maintain Isabelle etc. (in parts
  4993 still somewhat experimental); old Makefiles etc. still functional;
  4994 
  4995 * new 'Isabelle System Manual';
  4996 
  4997 * INSTALL text, together with ./configure and ./build scripts;
  4998 
  4999 * reimplemented type inference for greater efficiency, better error
  5000 messages and clean internal interface;
  5001 
  5002 * prlim command for dealing with lots of subgoals (an easier way of
  5003 setting goals_limit);
  5004 
  5005 
  5006 *** Syntax ***
  5007 
  5008 * supports alternative (named) syntax tables (parser and pretty
  5009 printer); internal interface is provided by add_modesyntax(_i);
  5010 
  5011 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5012 be used in conjunction with the Isabelle symbol font; uses the
  5013 "symbols" syntax table;
  5014 
  5015 * added token_translation interface (may translate name tokens in
  5016 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5017 the current print_mode); IMPORTANT: user print translation functions
  5018 are responsible for marking newly introduced bounds
  5019 (Syntax.mark_boundT);
  5020 
  5021 * token translations for modes "xterm" and "xterm_color" that display
  5022 names in bold, underline etc. or colors (which requires a color
  5023 version of xterm);
  5024 
  5025 * infixes may now be declared with names independent of their syntax;
  5026 
  5027 * added typed_print_translation (like print_translation, but may
  5028 access type of constant);
  5029 
  5030 
  5031 *** Classical Reasoner ***
  5032 
  5033 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5034 some limitations.  Blast_tac...
  5035   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5036   + ignores elimination rules that don't have the correct format
  5037         (the conclusion MUST be a formula variable)
  5038   + ignores types, which can make HOL proofs fail
  5039   + rules must not require higher-order unification, e.g. apply_type in ZF
  5040     [message "Function Var's argument not a bound variable" relates to this]
  5041   + its proof strategy is more general but can actually be slower
  5042 
  5043 * substitution with equality assumptions no longer permutes other
  5044 assumptions;
  5045 
  5046 * minor changes in semantics of addafter (now called addaltern); renamed
  5047 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5048 (and access functions for it);
  5049 
  5050 * improved combination of classical reasoner and simplifier:
  5051   + functions for handling clasimpsets
  5052   + improvement of addss: now the simplifier is called _after_ the
  5053     safe steps.
  5054   + safe variant of addss called addSss: uses safe simplifications
  5055     _during_ the safe steps. It is more complete as it allows multiple
  5056     instantiations of unknowns (e.g. with slow_tac).
  5057 
  5058 *** Simplifier ***
  5059 
  5060 * added interface for simplification procedures (functions that
  5061 produce *proven* rewrite rules on the fly, depending on current
  5062 redex);
  5063 
  5064 * ordering on terms as parameter (used for ordered rewriting);
  5065 
  5066 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5067 
  5068 * the solver is now split into a safe and an unsafe part.
  5069 This should be invisible for the normal user, except that the
  5070 functions setsolver and addsolver have been renamed to setSolver and
  5071 addSolver; added safe_asm_full_simp_tac;
  5072 
  5073 
  5074 *** HOL ***
  5075 
  5076 * a generic induction tactic `induct_tac' which works for all datatypes and
  5077 also for type `nat';
  5078 
  5079 * a generic case distinction tactic `exhaust_tac' which works for all
  5080 datatypes and also for type `nat';
  5081 
  5082 * each datatype comes with a function `size';
  5083 
  5084 * patterns in case expressions allow tuple patterns as arguments to
  5085 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5086 
  5087 * primrec now also works with type nat;
  5088 
  5089 * recdef: a new declaration form, allows general recursive functions to be
  5090 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5091 
  5092 * the constant for negation has been renamed from "not" to "Not" to
  5093 harmonize with FOL, ZF, LK, etc.;
  5094 
  5095 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5096 infinite lists;
  5097 
  5098 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5099 
  5100 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5101 problems in commutative rings, using axiomatic type classes for + and *;
  5102 
  5103 * more examples in HOL/MiniML and HOL/Auth;
  5104 
  5105 * more default rewrite rules for quantifiers, union/intersection;
  5106 
  5107 * a new constant `arbitrary == @x.False';
  5108 
  5109 * HOLCF/IOA replaces old HOL/IOA;
  5110 
  5111 * HOLCF changes: derived all rules and arities
  5112   + axiomatic type classes instead of classes
  5113   + typedef instead of faking type definitions
  5114   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5115   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5116   + eliminated the types void, one, tr
  5117   + use unit lift and bool lift (with translations) instead of one and tr
  5118   + eliminated blift from Lift3.thy (use Def instead of blift)
  5119   all eliminated rules are derived as theorems --> no visible changes ;
  5120 
  5121 
  5122 *** ZF ***
  5123 
  5124 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5125 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5126 as ZF_cs addSIs [equalityI];
  5127 
  5128 
  5129 
  5130 New in Isabelle94-7 (November 96)
  5131 ---------------------------------
  5132 
  5133 * allowing negative levels (as offsets) in prlev and choplev;
  5134 
  5135 * super-linear speedup for large simplifications;
  5136 
  5137 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5138 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5139 FAIL); can suppress it using the command Delsimps (ex_simps @
  5140 all_simps); De Morgan laws are also now included, by default;
  5141 
  5142 * improved printing of ==>  :  ~:
  5143 
  5144 * new object-logic "Sequents" adds linear logic, while replacing LK
  5145 and Modal (thanks to Sara Kalvala);
  5146 
  5147 * HOL/Auth: correctness proofs for authentication protocols;
  5148 
  5149 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5150 examples on HOL/Auth);
  5151 
  5152 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5153 the rewriter and classical reasoner simultaneously;
  5154 
  5155 * function uresult no longer returns theorems in "standard" format;
  5156 regain previous version by: val uresult = standard o uresult;
  5157 
  5158 
  5159 
  5160 New in Isabelle94-6
  5161 -------------------
  5162 
  5163 * oracles -- these establish an interface between Isabelle and trusted
  5164 external reasoners, which may deliver results as theorems;
  5165 
  5166 * proof objects (in particular record all uses of oracles);
  5167 
  5168 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5169 
  5170 * "constdefs" section in theory files;
  5171 
  5172 * "primrec" section (HOL) no longer requires names;
  5173 
  5174 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5175 
  5176 
  5177 
  5178 New in Isabelle94-5
  5179 -------------------
  5180 
  5181 * reduced space requirements;
  5182 
  5183 * automatic HTML generation from theories;
  5184 
  5185 * theory files no longer require "..." (quotes) around most types;
  5186 
  5187 * new examples, including two proofs of the Church-Rosser theorem;
  5188 
  5189 * non-curried (1994) version of HOL is no longer distributed;
  5190 
  5191 
  5192 
  5193 New in Isabelle94-4
  5194 -------------------
  5195 
  5196 * greatly reduced space requirements;
  5197 
  5198 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5199 
  5200 * searchable theorem database (see the section "Retrieving theorems" on
  5201 page 8 of the Reference Manual);
  5202 
  5203 * new examples, including Grabczewski's monumental case study of the
  5204 Axiom of Choice;
  5205 
  5206 * The previous version of HOL renamed to Old_HOL;
  5207 
  5208 * The new version of HOL (previously called CHOL) uses a curried syntax
  5209 for functions.  Application looks like f a b instead of f(a,b);
  5210 
  5211 * Mutually recursive inductive definitions finally work in HOL;
  5212 
  5213 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5214 translates to the operator "split";
  5215 
  5216 
  5217 
  5218 New in Isabelle94-3
  5219 -------------------
  5220 
  5221 * new infix operator, addss, allowing the classical reasoner to
  5222 perform simplification at each step of its search.  Example:
  5223         fast_tac (cs addss ss)
  5224 
  5225 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5226 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5227 look like (a,b) instead of <a,b>;
  5228 
  5229 * PLEASE NOTE: CHOL will eventually replace HOL!
  5230 
  5231 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5232 It translates to the operator "split".  A new theory of integers is available;
  5233 
  5234 * In ZF, integer numerals now denote two's-complement binary integers.
  5235 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5236 
  5237 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5238 of the Axiom of Choice;
  5239 
  5240 
  5241 
  5242 New in Isabelle94-2
  5243 -------------------
  5244 
  5245 * Significantly faster resolution;
  5246 
  5247 * the different sections in a .thy file can now be mixed and repeated
  5248 freely;
  5249 
  5250 * Database of theorems for FOL, HOL and ZF.  New
  5251 commands including qed, qed_goal and bind_thm store theorems in the database.
  5252 
  5253 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5254 a given theory (thms_of), or find out what theory a theorem was proved in
  5255 (theory_of_thm);
  5256 
  5257 * Bugs fixed in the inductive definition and datatype packages;
  5258 
  5259 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5260 and HOL_dup_cs obsolete;
  5261 
  5262 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5263 have been removed;
  5264 
  5265 * Simpler definition of function space in ZF;
  5266 
  5267 * new results about cardinal and ordinal arithmetic in ZF;
  5268 
  5269 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5270 types;
  5271 
  5272 :mode=text:wrap=hard:maxLineLen=72:
  5273 
  5274 $Id$