NEWS
author haftmann
Fri Dec 07 15:07:59 2007 +0100 (2007-12-07)
changeset 25571 c9e39eafc7a0
parent 25557 ea6b11021e79
child 25579 22869d9d545b
permissions -rw-r--r--
instantiation target rather than legacy instance
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Symbol \<chi> is now considered a letter.  Potential INCOMPATIBILITY
    10 in identifier syntax etc.
    11 
    12 
    13 *** Pure ***
    14 
    15 * Command "instance" now takes list of definitions in the same manner
    16 as the "definition" command.  Most notably, object equality is now
    17 possible.  Type inference is more canonical than it used to be.
    18 INCOMPATIBILITY: in some cases explicit type annotations are required.
    19 
    20 
    21 *** HOL ***
    22 
    23 * New primrec package.  Specification syntax conforms in style to
    24   definition/function/....  The "primrec" command distinguished old-style
    25   and new-style specifications by syntax.  The old primrec package is
    26   now named OldPrimrecPackage.
    27 
    28 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
    29 
    30 * Constants "card", "internal_split", "option_map" now with authentic
    31 syntax.
    32 
    33 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
    34 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
    35 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
    36 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
    37 Sup_set_def, le_def, less_def, option_map_def now with object
    38 equality.
    39 
    40 
    41 
    42 New in Isabelle2007 (November 2007)
    43 -----------------------------------
    44 
    45 *** General ***
    46 
    47 * More uniform information about legacy features, notably a
    48 warning/error of "Legacy feature: ...", depending on the state of the
    49 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
    50 legacy features will disappear eventually.
    51 
    52 * Theory syntax: the header format ``theory A = B + C:'' has been
    53 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    54 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    55 
    56 * Theory syntax: the old non-Isar theory file format has been
    57 discontinued altogether.  Note that ML proof scripts may still be used
    58 with Isar theories; migration is usually quite simple with the ML
    59 function use_legacy_bindings.  INCOMPATIBILITY.
    60 
    61 * Theory syntax: some popular names (e.g. 'class', 'declaration',
    62 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
    63 quotes.
    64 
    65 * Theory loader: be more serious about observing the static theory
    66 header specifications (including optional directories), but not the
    67 accidental file locations of previously successful loads.  The strict
    68 update policy of former update_thy is now already performed by
    69 use_thy, so the former has been removed; use_thys updates several
    70 theories simultaneously, just as 'imports' within a theory header
    71 specification, but without merging the results.  Potential
    72 INCOMPATIBILITY: may need to refine theory headers and commands
    73 ROOT.ML which depend on load order.
    74 
    75 * Theory loader: optional support for content-based file
    76 identification, instead of the traditional scheme of full physical
    77 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
    78 (cf. the system manual).  The new scheme allows to work with
    79 non-finished theories in persistent session images, such that source
    80 files may be moved later on without requiring reloads.
    81 
    82 * Theory loader: old-style ML proof scripts being *attached* to a thy
    83 file (with the same base name as the theory) are considered a legacy
    84 feature, which will disappear eventually. Even now, the theory loader
    85 no longer maintains dependencies on such files.
    86 
    87 * Syntax: the scope for resolving ambiguities via type-inference is
    88 now limited to individual terms, instead of whole simultaneous
    89 specifications as before. This greatly reduces the complexity of the
    90 syntax module and improves flexibility by separating parsing and
    91 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
    92 'fixes' etc.) are required in rare situations.
    93 
    94 * Syntax: constants introduced by new-style packages ('definition',
    95 'abbreviation' etc.) are passed through the syntax module in
    96 ``authentic mode''. This means that associated mixfix annotations
    97 really stick to such constants, independently of potential name space
    98 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
    99 trees are represented slightly differently, may need to adapt syntax
   100 translations accordingly. Use CONST marker in 'translations' and
   101 @{const_syntax} antiquotation in 'parse_translation' etc.
   102 
   103 * Legacy goal package: reduced interface to the bare minimum required
   104 to keep existing proof scripts running.  Most other user-level
   105 functions are now part of the OldGoals structure, which is *not* open
   106 by default (consider isatool expandshort before open OldGoals).
   107 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   108 these tend to cause confusion about the actual goal (!) context being
   109 used here, which is not necessarily the same as the_context().
   110 
   111 * Command 'find_theorems': supports "*" wild-card in "name:"
   112 criterion; "with_dups" option.  Certain ProofGeneral versions might
   113 support a specific search form (see ProofGeneral/CHANGES).
   114 
   115 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   116 by default, which means that "prems" (and also "fixed variables") are
   117 suppressed from proof state output.  Note that the ProofGeneral
   118 settings mechanism allows to change and save options persistently, but
   119 older versions of Isabelle will fail to start up if a negative prems
   120 limit is imposed.
   121 
   122 * Local theory targets may be specified by non-nested blocks of
   123 ``context/locale/class ... begin'' followed by ``end''.  The body may
   124 contain definitions, theorems etc., including any derived mechanism
   125 that has been implemented on top of these primitives.  This concept
   126 generalizes the existing ``theorem (in ...)'' towards more versatility
   127 and scalability.
   128 
   129 * Proof General interface: proper undo of final 'end' command;
   130 discontinued Isabelle/classic mode (ML proof scripts).
   131 
   132 
   133 *** Document preparation ***
   134 
   135 * Added antiquotation @{theory name} which prints the given name,
   136 after checking that it refers to a valid ancestor theory in the
   137 current context.
   138 
   139 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   140 check the given source text as ML type/structure, printing verbatim.
   141 
   142 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   143 "c args == rhs" given in the current context.  (Any number of
   144 arguments may be given on the LHS.)
   145 
   146 
   147 *** Pure ***
   148 
   149 * The 'class' package offers a combination of axclass and locale to
   150 achieve Haskell-like type classes in Isabelle.  Definitions and
   151 theorems within a class context produce both relative results (with
   152 implicit parameters according to the locale context), and polymorphic
   153 constants with qualified polymorphism (according to the class
   154 context).  Within the body context of a 'class' target, a separate
   155 syntax layer ("user space type system") takes care of converting
   156 between global polymorphic consts and internal locale representation.
   157 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   158 "isatool doc classes" provides a tutorial.
   159 
   160 * Generic code generator framework allows to generate executable
   161 code for ML and Haskell (including Isabelle classes).  A short usage
   162 sketch:
   163 
   164     internal compilation:
   165         export_code <list of constants (term syntax)> in SML
   166     writing SML code to a file:
   167         export_code <list of constants (term syntax)> in SML <filename>
   168     writing OCaml code to a file:
   169         export_code <list of constants (term syntax)> in OCaml <filename>
   170     writing Haskell code to a bunch of files:
   171         export_code <list of constants (term syntax)> in Haskell <filename>
   172 
   173     evaluating closed propositions to True/False using code generation:
   174         method ``eval''
   175 
   176 Reasonable default setup of framework in HOL.
   177 
   178 Theorem attributs for selecting and transforming function equations theorems:
   179 
   180     [code fun]:        select a theorem as function equation for a specific constant
   181     [code fun del]:    deselect a theorem as function equation for a specific constant
   182     [code inline]:     select an equation theorem for unfolding (inlining) in place
   183     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   184 
   185 User-defined serializations (target in {SML, OCaml, Haskell}):
   186 
   187     code_const <and-list of constants (term syntax)>
   188       {(target) <and-list of const target syntax>}+
   189 
   190     code_type <and-list of type constructors>
   191       {(target) <and-list of type target syntax>}+
   192 
   193     code_instance <and-list of instances>
   194       {(target)}+
   195         where instance ::= <type constructor> :: <class>
   196 
   197     code_class <and_list of classes>
   198       {(target) <and-list of class target syntax>}+
   199         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   200 
   201 code_instance and code_class only are effective to target Haskell.
   202 
   203 For example usage see src/HOL/ex/Codegenerator.thy and
   204 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   205 generation from Isabelle/HOL theories is available via "isatool doc
   206 codegen".
   207 
   208 * Code generator: consts in 'consts_code' Isar commands are now
   209 referred to by usual term syntax (including optional type
   210 annotations).
   211 
   212 * Command 'no_translations' removes translation rules from theory
   213 syntax.
   214 
   215 * Overloaded definitions are now actually checked for acyclic
   216 dependencies.  The overloading scheme is slightly more general than
   217 that of Haskell98, although Isabelle does not demand an exact
   218 correspondence to type class and instance declarations.
   219 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   220 exotic versions of overloading -- at the discretion of the user!
   221 
   222 Polymorphic constants are represented via type arguments, i.e. the
   223 instantiation that matches an instance against the most general
   224 declaration given in the signature.  For example, with the declaration
   225 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   226 as c(nat).  Overloading is essentially simultaneous structural
   227 recursion over such type arguments.  Incomplete specification patterns
   228 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   229 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   230 Command 'print_theory' outputs the normalized system of recursive
   231 equations, see section "definitions".
   232 
   233 * Configuration options are maintained within the theory or proof
   234 context (with name and type bool/int/string), providing a very simple
   235 interface to a poor-man's version of general context data.  Tools may
   236 declare options in ML (e.g. using Attrib.config_int) and then refer to
   237 these values using Config.get etc.  Users may change options via an
   238 associated attribute of the same name.  This form of context
   239 declaration works particularly well with commands 'declare' or
   240 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   241 very easy to avoid global references, which would not observe Isar
   242 toplevel undo/redo and fail to work with multithreading.
   243 
   244 Various global ML references of Pure and HOL have been turned into
   245 configuration options:
   246 
   247   Unify.search_bound		unify_search_bound
   248   Unify.trace_bound		unify_trace_bound
   249   Unify.trace_simp		unify_trace_simp
   250   Unify.trace_types		unify_trace_types
   251   Simplifier.simp_depth_limit	simp_depth_limit
   252   Blast.depth_limit		blast_depth_limit
   253   DatatypeProp.dtK		datatype_distinctness_limit
   254   fast_arith_neq_limit  	fast_arith_neq_limit
   255   fast_arith_split_limit	fast_arith_split_limit
   256 
   257 * Named collections of theorems may be easily installed as context
   258 data using the functor NamedThmsFun (see also
   259 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   260 attributes; there is also a toplevel print command.  This facility is
   261 just a common case of general context data, which is the preferred way
   262 for anything more complex than just a list of facts in canonical
   263 order.
   264 
   265 * Isar: command 'declaration' augments a local theory by generic
   266 declaration functions written in ML.  This enables arbitrary content
   267 being added to the context, depending on a morphism that tells the
   268 difference of the original declaration context wrt. the application
   269 context encountered later on.
   270 
   271 * Isar: proper interfaces for simplification procedures.  Command
   272 'simproc_setup' declares named simprocs (with match patterns, and body
   273 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   274 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   275 
   276 * Isar: an extra pair of brackets around attribute declarations
   277 abbreviates a theorem reference involving an internal dummy fact,
   278 which will be ignored later --- only the effect of the attribute on
   279 the background context will persist.  This form of in-place
   280 declarations is particularly useful with commands like 'declare' and
   281 'using', for example ``have A using [[simproc a]] by simp''.
   282 
   283 * Isar: method "assumption" (and implicit closing of subproofs) now
   284 takes simple non-atomic goal assumptions into account: after applying
   285 an assumption as a rule the resulting subgoals are solved by atomic
   286 assumption steps.  This is particularly useful to finish 'obtain'
   287 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   288 without referring to the original premise "!!x. P x ==> thesis" in the
   289 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   290 more permissive.
   291 
   292 * Isar: implicit use of prems from the Isar proof context is
   293 considered a legacy feature.  Common applications like ``have A .''
   294 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   295 referencing facts explicitly here improves readability and
   296 maintainability of proof texts.
   297 
   298 * Isar: improper proof element 'guess' is like 'obtain', but derives
   299 the obtained context from the course of reasoning!  For example:
   300 
   301   assume "EX x y. A x & B y"   -- "any previous fact"
   302   then guess x and y by clarify
   303 
   304 This technique is potentially adventurous, depending on the facts and
   305 proof tools being involved here.
   306 
   307 * Isar: known facts from the proof context may be specified as literal
   308 propositions, using ASCII back-quote syntax.  This works wherever
   309 named facts used to be allowed so far, in proof commands, proof
   310 methods, attributes etc.  Literal facts are retrieved from the context
   311 according to unification of type and term parameters.  For example,
   312 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   313 theorems in the current context, then these are valid literal facts:
   314 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   315 
   316 There is also a proof method "fact" which does the same composition
   317 for explicit goal states, e.g. the following proof texts coincide with
   318 certain special cases of literal facts:
   319 
   320   have "A" by fact                 ==  note `A`
   321   have "A ==> B" by fact           ==  note `A ==> B`
   322   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   323   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   324 
   325 * Isar: ":" (colon) is no longer a symbolic identifier character in
   326 outer syntax.  Thus symbolic identifiers may be used without
   327 additional white space in declarations like this: ``assume *: A''.
   328 
   329 * Isar: 'print_facts' prints all local facts of the current context,
   330 both named and unnamed ones.
   331 
   332 * Isar: 'def' now admits simultaneous definitions, e.g.:
   333 
   334   def x == "t" and y == "u"
   335 
   336 * Isar: added command 'unfolding', which is structurally similar to
   337 'using', but affects both the goal state and facts by unfolding given
   338 rewrite rules.  Thus many occurrences of the 'unfold' method or
   339 'unfolded' attribute may be replaced by first-class proof text.
   340 
   341 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   342 and command 'unfolding' now all support object-level equalities
   343 (potentially conditional).  The underlying notion of rewrite rule is
   344 analogous to the 'rule_format' attribute, but *not* that of the
   345 Simplifier (which is usually more generous).
   346 
   347 * Isar: the new attribute [rotated n] (default n = 1) rotates the
   348 premises of a theorem by n. Useful in conjunction with drule.
   349 
   350 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   351 method expression within a sandbox consisting of the first N
   352 sub-goals, which need to exist.  For example, ``simp_all [3]''
   353 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   354 simplifies all new goals that emerge from applying rule foo to the
   355 originally first one.
   356 
   357 * Isar: schematic goals are no longer restricted to higher-order
   358 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   359 expected.
   360 
   361 * Isar: the conclusion of a long theorem statement is now either
   362 'shows' (a simultaneous conjunction, as before), or 'obtains'
   363 (essentially a disjunction of cases with local parameters and
   364 assumptions).  The latter allows to express general elimination rules
   365 adequately; in this notation common elimination rules look like this:
   366 
   367   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   368     assumes "EX x. P x"
   369     obtains x where "P x"
   370 
   371   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   372     assumes "A & B"
   373     obtains A and B
   374 
   375   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   376     assumes "A | B"
   377     obtains
   378       A
   379     | B
   380 
   381 The subsequent classical rules even refer to the formal "thesis"
   382 explicitly:
   383 
   384   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   385     obtains "~ thesis"
   386 
   387   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   388     obtains "thesis ==> something"
   389 
   390 The actual proof of an 'obtains' statement is analogous to that of the
   391 Isar proof element 'obtain', only that there may be several cases.
   392 Optional case names may be specified in parentheses; these will be
   393 available both in the present proof and as annotations in the
   394 resulting rule, for later use with the 'cases' method (cf. attribute
   395 case_names).
   396 
   397 * Isar: the assumptions of a long theorem statement are available as
   398 "assms" fact in the proof context.  This is more appropriate than the
   399 (historical) "prems", which refers to all assumptions of the current
   400 context, including those from the target locale, proof body etc.
   401 
   402 * Isar: 'print_statement' prints theorems from the current theory or
   403 proof context in long statement form, according to the syntax of a
   404 top-level lemma.
   405 
   406 * Isar: 'obtain' takes an optional case name for the local context
   407 introduction rule (default "that").
   408 
   409 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   410 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   411 to occur.
   412 
   413 * Pure: syntax "CONST name" produces a fully internalized constant
   414 according to the current context.  This is particularly useful for
   415 syntax translations that should refer to internal constant
   416 representations independently of name spaces.
   417 
   418 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   419 instead of "FOO ". This allows multiple binder declarations to coexist
   420 in the same context.  INCOMPATIBILITY.
   421 
   422 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   423 primitive that also works in a locale context (both for constants and
   424 fixed variables). Type declaration and internal syntactic representation
   425 of given constants retrieved from the context. Likewise, the
   426 'no_notation' command allows to remove given syntax annotations from the
   427 current context.
   428 
   429 * Isar/locales: new derived specification elements 'axiomatization',
   430 'definition', 'abbreviation', which support type-inference, admit
   431 object-level specifications (equality, equivalence).  See also the
   432 isar-ref manual.  Examples:
   433 
   434   axiomatization
   435     eq  (infix "===" 50) where
   436     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   437 
   438   definition "f x y = x + y + 1"
   439   definition g where "g x = f x x"
   440 
   441   abbreviation
   442     neq  (infix "=!=" 50) where
   443     "x =!= y == ~ (x === y)"
   444 
   445 These specifications may be also used in a locale context.  Then the
   446 constants being introduced depend on certain fixed parameters, and the
   447 constant name is qualified by the locale base name.  An internal
   448 abbreviation takes care for convenient input and output, making the
   449 parameters implicit and using the original short name.  See also
   450 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   451 entities from a monomorphic theory.
   452 
   453 Presently, abbreviations are only available 'in' a target locale, but
   454 not inherited by general import expressions.  Also note that
   455 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   456 'translations' in common applications.  The "no_abbrevs" print mode
   457 prevents folding of abbreviations in term output.
   458 
   459 Concrete syntax is attached to specified constants in internal form,
   460 independently of name spaces.  The parse tree representation is
   461 slightly different -- use 'notation' instead of raw 'syntax', and
   462 'translations' with explicit "CONST" markup to accommodate this.
   463 
   464 * Pure/Isar: unified syntax for new-style specification mechanisms
   465 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
   466 full type inference and dummy patterns ("_").  For example:
   467 
   468   definition "K x _ = x"
   469 
   470   inductive conj for A B
   471   where "A ==> B ==> conj A B"
   472 
   473 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   474 the current context.  Print mode "no_abbrevs" prevents inversion of
   475 abbreviations on output.
   476 
   477 * Isar/locales: improved parameter handling: use of locales "var" and
   478 "struct" no longer necessary; - parameter renamings are no longer
   479 required to be injective.  For example, this allows to define
   480 endomorphisms as locale endom = homom mult mult h.
   481 
   482 * Isar/locales: changed the way locales with predicates are defined.
   483 Instead of accumulating the specification, the imported expression is
   484 now an interpretation.  INCOMPATIBILITY: different normal form of
   485 locale expressions.  In particular, in interpretations of locales with
   486 predicates, goals repesenting already interpreted fragments are not
   487 removed automatically.  Use methods `intro_locales' and
   488 `unfold_locales'; see below.
   489 
   490 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   491 provide backward reasoning on locales predicates.  The methods are
   492 aware of interpretations and discharge corresponding goals.
   493 `intro_locales' is less aggressive then `unfold_locales' and does not
   494 unfold predicates to assumptions.
   495 
   496 * Isar/locales: the order in which locale fragments are accumulated
   497 has changed.  This enables to override declarations from fragments due
   498 to interpretations -- for example, unwanted simp rules.
   499 
   500 * Isar/locales: interpretation in theories and proof contexts has been
   501 extended.  One may now specify (and prove) equations, which are
   502 unfolded in interpreted theorems.  This is useful for replacing
   503 defined concepts (constants depending on locale parameters) by
   504 concepts already existing in the target context.  Example:
   505 
   506   interpretation partial_order ["op <= :: [int, int] => bool"]
   507     where "partial_order.less (op <=) (x::int) y = (x < y)"
   508 
   509 Typically, the constant `partial_order.less' is created by a
   510 definition specification element in the context of locale
   511 partial_order.
   512 
   513 * Method "induct": improved internal context management to support
   514 local fixes and defines on-the-fly. Thus explicit meta-level
   515 connectives !!  and ==> are rarely required anymore in inductive goals
   516 (using object-logic connectives for this purpose has been long
   517 obsolete anyway). Common proof patterns are explained in
   518 src/HOL/Induct/Common_Patterns.thy, see also
   519 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
   520 examples.
   521 
   522 * Method "induct": improved handling of simultaneous goals. Instead of
   523 introducing object-level conjunction, the statement is now split into
   524 several conclusions, while the corresponding symbolic cases are nested
   525 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
   526 see src/HOL/Induct/Common_Patterns.thy, for example.
   527 
   528 * Method "induct": mutual induction rules are now specified as a list
   529 of rule sharing the same induction cases. HOL packages usually provide
   530 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
   531 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
   532 mutual induction rules differently, i.e. like this:
   533 
   534   (induct rule: foo_bar.inducts)
   535   (induct set: foo bar)
   536   (induct pred: foo bar)
   537   (induct type: foo bar)
   538 
   539 The ML function ProjectRule.projections turns old-style rules into the
   540 new format.
   541 
   542 * Method "coinduct": dual of induction, see
   543 src/HOL/Library/Coinductive_List.thy for various examples.
   544 
   545 * Method "cases", "induct", "coinduct": the ``(open)'' option is
   546 considered a legacy feature.
   547 
   548 * Attribute "symmetric" produces result with standardized schematic
   549 variables (index 0).  Potential INCOMPATIBILITY.
   550 
   551 * Simplifier: by default the simplifier trace only shows top level
   552 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   553 default. Thus there is less danger of being flooded by the trace. The
   554 trace indicates where parts have been suppressed.
   555   
   556 * Provers/classical: removed obsolete classical version of elim_format
   557 attribute; classical elim/dest rules are now treated uniformly when
   558 manipulating the claset.
   559 
   560 * Provers/classical: stricter checks to ensure that supplied intro,
   561 dest and elim rules are well-formed; dest and elim rules must have at
   562 least one premise.
   563 
   564 * Provers/classical: attributes dest/elim/intro take an optional
   565 weight argument for the rule (just as the Pure versions).  Weights are
   566 ignored by automated tools, but determine the search order of single
   567 rule steps.
   568 
   569 * Syntax: input syntax now supports dummy variable binding "%_. b",
   570 where the body does not mention the bound variable.  Note that dummy
   571 patterns implicitly depend on their context of bounds, which makes
   572 "{_. _}" match any set comprehension as expected.  Potential
   573 INCOMPATIBILITY -- parse translations need to cope with syntactic
   574 constant "_idtdummy" in the binding position.
   575 
   576 * Syntax: removed obsolete syntactic constant "_K" and its associated
   577 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   578 for example "A -> B" => "Pi A (%_. B)".
   579 
   580 * Pure: 'class_deps' command visualizes the subclass relation, using
   581 the graph browser tool.
   582 
   583 * Pure: 'print_theory' now suppresses certain internal declarations by
   584 default; use '!' option for full details.
   585 
   586 
   587 *** HOL ***
   588 
   589 * Method "metis" proves goals by applying the Metis general-purpose
   590 resolution prover (see also http://gilith.com/software/metis/).
   591 Examples are in the directory MetisExamples.  WARNING: the
   592 Isabelle/HOL-Metis integration does not yet work properly with
   593 multi-threading.
   594   
   595 * Command 'sledgehammer' invokes external automatic theorem provers as
   596 background processes.  It generates calls to the "metis" method if
   597 successful. These can be pasted into the proof.  Users do not have to
   598 wait for the automatic provers to return.  WARNING: does not really
   599 work with multi-threading.
   600 
   601 * New "auto_quickcheck" feature tests outermost goal statements for
   602 potential counter-examples.  Controlled by ML references
   603 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
   604 5000 milliseconds).  Fails silently if statements is outside of
   605 executable fragment, or any other codgenerator problem occurs.
   606 
   607 * New constant "undefined" with axiom "undefined x = undefined".
   608 
   609 * Added class "HOL.eq", allowing for code generation with polymorphic
   610 equality.
   611 
   612 * Some renaming of class constants due to canonical name prefixing in
   613 the new 'class' package:
   614 
   615     HOL.abs ~> HOL.abs_class.abs
   616     HOL.divide ~> HOL.divide_class.divide
   617     0 ~> HOL.zero_class.zero
   618     1 ~> HOL.one_class.one
   619     op + ~> HOL.plus_class.plus
   620     op - ~> HOL.minus_class.minus
   621     uminus ~> HOL.minus_class.uminus
   622     op * ~> HOL.times_class.times
   623     op < ~> HOL.ord_class.less
   624     op <= > HOL.ord_class.less_eq
   625     Nat.power ~> Power.power_class.power
   626     Nat.size ~> Nat.size_class.size
   627     Numeral.number_of ~> Numeral.number_class.number_of
   628     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
   629     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
   630     Orderings.min ~> Orderings.ord_class.min
   631     Orderings.max ~> Orderings.ord_class.max
   632     Divides.op div ~> Divides.div_class.div
   633     Divides.op mod ~> Divides.div_class.mod
   634     Divides.op dvd ~> Divides.div_class.dvd
   635 
   636 INCOMPATIBILITY.  Adaptions may be required in the following cases:
   637 
   638 a) User-defined constants using any of the names "plus", "minus",
   639 "times", "less" or "less_eq". The standard syntax translations for
   640 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
   641 names.
   642 
   643 b) Variables named "plus", "minus", "times", "less", "less_eq"
   644 INCOMPATIBILITY: use more specific names.
   645 
   646 c) Permutative equations (e.g. "a + b = b + a")
   647 Since the change of names also changes the order of terms, permutative
   648 rewrite rules may get applied in a different order. Experience shows
   649 that this is rarely the case (only two adaptions in the whole Isabelle
   650 distribution).  INCOMPATIBILITY: rewrite proofs
   651 
   652 d) ML code directly refering to constant names
   653 This in general only affects hand-written proof tactics, simprocs and
   654 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
   655 Consider using @{const_name} antiquotation.
   656 
   657 * New class "default" with associated constant "default".
   658 
   659 * Function "sgn" is now overloaded and available on int, real, complex
   660 (and other numeric types), using class "sgn".  Two possible defs of
   661 sgn are given as equational assumptions in the classes sgn_if and
   662 sgn_div_norm; ordered_idom now also inherits from sgn_if.
   663 INCOMPATIBILITY.
   664 
   665 * Locale "partial_order" now unified with class "order" (cf. theory
   666 Orderings), added parameter "less".  INCOMPATIBILITY.
   667 
   668 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
   669 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
   670 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
   671 
   672 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
   673 changed order of proof goals in instance proofs.
   674 
   675 * The transitivity reasoner for partial and linear orders is set up
   676 for classes "order" and "linorder".  Instances of the reasoner are available
   677 in all contexts importing or interpreting the corresponding locales.
   678 Method "order" invokes the reasoner separately; the reasoner
   679 is also integrated with the Simplifier as a solver.  Diagnostic
   680 command 'print_orders' shows the available instances of the reasoner
   681 in the current context.
   682 
   683 * Localized monotonicity predicate in theory "Orderings"; integrated
   684 lemmas max_of_mono and min_of_mono with this predicate.
   685 INCOMPATIBILITY.
   686 
   687 * Formulation of theorem "dense" changed slightly due to integration
   688 with new class dense_linear_order.
   689 
   690 * Uniform lattice theory development in HOL.
   691 
   692     constants "meet" and "join" now named "inf" and "sup"
   693     constant "Meet" now named "Inf"
   694 
   695     classes "meet_semilorder" and "join_semilorder" now named
   696       "lower_semilattice" and "upper_semilattice"
   697     class "lorder" now named "lattice"
   698     class "comp_lat" now named "complete_lattice"
   699 
   700     Instantiation of lattice classes allows explicit definitions
   701     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
   702 
   703   INCOMPATIBILITY.  Theorem renames:
   704 
   705     meet_left_le            ~> inf_le1
   706     meet_right_le           ~> inf_le2
   707     join_left_le            ~> sup_ge1
   708     join_right_le           ~> sup_ge2
   709     meet_join_le            ~> inf_sup_ord
   710     le_meetI                ~> le_infI
   711     join_leI                ~> le_supI
   712     le_meet                 ~> le_inf_iff
   713     le_join                 ~> ge_sup_conv
   714     meet_idempotent         ~> inf_idem
   715     join_idempotent         ~> sup_idem
   716     meet_comm               ~> inf_commute
   717     join_comm               ~> sup_commute
   718     meet_leI1               ~> le_infI1
   719     meet_leI2               ~> le_infI2
   720     le_joinI1               ~> le_supI1
   721     le_joinI2               ~> le_supI2
   722     meet_assoc              ~> inf_assoc
   723     join_assoc              ~> sup_assoc
   724     meet_left_comm          ~> inf_left_commute
   725     meet_left_idempotent    ~> inf_left_idem
   726     join_left_comm          ~> sup_left_commute
   727     join_left_idempotent    ~> sup_left_idem
   728     meet_aci                ~> inf_aci
   729     join_aci                ~> sup_aci
   730     le_def_meet             ~> le_iff_inf
   731     le_def_join             ~> le_iff_sup
   732     join_absorp2            ~> sup_absorb2
   733     join_absorp1            ~> sup_absorb1
   734     meet_absorp1            ~> inf_absorb1
   735     meet_absorp2            ~> inf_absorb2
   736     meet_join_absorp        ~> inf_sup_absorb
   737     join_meet_absorp        ~> sup_inf_absorb
   738     distrib_join_le         ~> distrib_sup_le
   739     distrib_meet_le         ~> distrib_inf_le
   740 
   741     add_meet_distrib_left   ~> add_inf_distrib_left
   742     add_join_distrib_left   ~> add_sup_distrib_left
   743     is_join_neg_meet        ~> is_join_neg_inf
   744     is_meet_neg_join        ~> is_meet_neg_sup
   745     add_meet_distrib_right  ~> add_inf_distrib_right
   746     add_join_distrib_right  ~> add_sup_distrib_right
   747     add_meet_join_distribs  ~> add_sup_inf_distribs
   748     join_eq_neg_meet        ~> sup_eq_neg_inf
   749     meet_eq_neg_join        ~> inf_eq_neg_sup
   750     add_eq_meet_join        ~> add_eq_inf_sup
   751     meet_0_imp_0            ~> inf_0_imp_0
   752     join_0_imp_0            ~> sup_0_imp_0
   753     meet_0_eq_0             ~> inf_0_eq_0
   754     join_0_eq_0             ~> sup_0_eq_0
   755     neg_meet_eq_join        ~> neg_inf_eq_sup
   756     neg_join_eq_meet        ~> neg_sup_eq_inf
   757     join_eq_if              ~> sup_eq_if
   758 
   759     mono_meet               ~> mono_inf
   760     mono_join               ~> mono_sup
   761     meet_bool_eq            ~> inf_bool_eq
   762     join_bool_eq            ~> sup_bool_eq
   763     meet_fun_eq             ~> inf_fun_eq
   764     join_fun_eq             ~> sup_fun_eq
   765     meet_set_eq             ~> inf_set_eq
   766     join_set_eq             ~> sup_set_eq
   767     meet1_iff               ~> inf1_iff
   768     meet2_iff               ~> inf2_iff
   769     meet1I                  ~> inf1I
   770     meet2I                  ~> inf2I
   771     meet1D1                 ~> inf1D1
   772     meet2D1                 ~> inf2D1
   773     meet1D2                 ~> inf1D2
   774     meet2D2                 ~> inf2D2
   775     meet1E                  ~> inf1E
   776     meet2E                  ~> inf2E
   777     join1_iff               ~> sup1_iff
   778     join2_iff               ~> sup2_iff
   779     join1I1                 ~> sup1I1
   780     join2I1                 ~> sup2I1
   781     join1I1                 ~> sup1I1
   782     join2I2                 ~> sup1I2
   783     join1CI                 ~> sup1CI
   784     join2CI                 ~> sup2CI
   785     join1E                  ~> sup1E
   786     join2E                  ~> sup2E
   787 
   788     is_meet_Meet            ~> is_meet_Inf
   789     Meet_bool_def           ~> Inf_bool_def
   790     Meet_fun_def            ~> Inf_fun_def
   791     Meet_greatest           ~> Inf_greatest
   792     Meet_lower              ~> Inf_lower
   793     Meet_set_def            ~> Inf_set_def
   794 
   795     Sup_def                 ~> Sup_Inf
   796     Sup_bool_eq             ~> Sup_bool_def
   797     Sup_fun_eq              ~> Sup_fun_def
   798     Sup_set_eq              ~> Sup_set_def
   799 
   800     listsp_meetI            ~> listsp_infI
   801     listsp_meet_eq          ~> listsp_inf_eq
   802 
   803     meet_min                ~> inf_min
   804     join_max                ~> sup_max
   805 
   806 * Added syntactic class "size"; overloaded constant "size" now has
   807 type "'a::size ==> bool"
   808 
   809 * Internal reorganisation of `size' of datatypes: size theorems
   810 "foo.size" are no longer subsumed by "foo.simps" (but are still
   811 simplification rules by default!); theorems "prod.size" now named
   812 "*.size".
   813 
   814 * Class "div" now inherits from class "times" rather than "type".
   815 INCOMPATIBILITY.
   816 
   817 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
   818 Linorder etc.  have disappeared; operations defined in terms of
   819 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
   820 
   821 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
   822 
   823 * HOL-Word: New extensive library and type for generic, fixed size
   824 machine words, with arithemtic, bit-wise, shifting and rotating
   825 operations, reflection into int, nat, and bool lists, automation for
   826 linear arithmetic (by automatic reflection into nat or int), including
   827 lemmas on overflow and monotonicity.  Instantiated to all appropriate
   828 arithmetic type classes, supporting automatic simplification of
   829 numerals on all operations.
   830 
   831 * Library/Boolean_Algebra: locales for abstract boolean algebras.
   832 
   833 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
   834 
   835 * Code generator library theories:
   836   - Code_Integer represents HOL integers by big integer literals in target
   837     languages.
   838   - Code_Char represents HOL characters by character literals in target
   839     languages.
   840   - Code_Char_chr like Code_Char, but also offers treatment of character
   841     codes; includes Code_Integer.
   842   - Executable_Set allows to generate code for finite sets using lists.
   843   - Executable_Rat implements rational numbers as triples (sign, enumerator,
   844     denominator).
   845   - Executable_Real implements a subset of real numbers, namly those
   846     representable by rational numbers.
   847   - Efficient_Nat implements natural numbers by integers, which in general will
   848     result in higher efficency; pattern matching with 0/Suc is eliminated;
   849     includes Code_Integer.
   850   - Code_Index provides an additional datatype index which is mapped to
   851     target-language built-in integers.
   852   - Code_Message provides an additional datatype message_string} which is isomorphic to
   853     strings; messages are mapped to target-language strings.
   854 
   855 * New package for inductive predicates
   856 
   857   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
   858 
   859     inductive
   860       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   861       for z_1 :: U_1 and ... and z_n :: U_m
   862     where
   863       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   864     | ...
   865 
   866   with full support for type-inference, rather than
   867 
   868     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   869 
   870     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   871     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   872 
   873     inductive "s z_1 ... z_m"
   874     intros
   875       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   876       ...
   877 
   878   For backward compatibility, there is a wrapper allowing inductive
   879   sets to be defined with the new package via
   880 
   881     inductive_set
   882       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   883       for z_1 :: U_1 and ... and z_n :: U_m
   884     where
   885       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   886     | ...
   887 
   888   or
   889 
   890     inductive_set
   891       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   892       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   893       for z_1 :: U_1 and ... and z_n :: U_m
   894     where
   895       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   896     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   897     | ...
   898 
   899   if the additional syntax "p ..." is required.
   900 
   901   Numerous examples can be found in the subdirectories src/HOL/Auth,
   902   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
   903 
   904   INCOMPATIBILITIES:
   905 
   906   - Since declaration and definition of inductive sets or predicates
   907     is no longer separated, abbreviations involving the newly
   908     introduced sets or predicates must be specified together with the
   909     introduction rules after the 'where' keyword (see above), rather
   910     than before the actual inductive definition.
   911 
   912   - The variables in induction and elimination rules are now
   913     quantified in the order of their occurrence in the introduction
   914     rules, rather than in alphabetical order. Since this may break
   915     some proofs, these proofs either have to be repaired, e.g. by
   916     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
   917     statements of the form
   918 
   919       case (rule_i a_i_1 ... a_i_{k_i})
   920 
   921     or the old order of quantification has to be restored by explicitly adding
   922     meta-level quantifiers in the introduction rules, i.e.
   923 
   924       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
   925 
   926   - The format of the elimination rules is now
   927 
   928       p z_1 ... z_m x_1 ... x_n ==>
   929         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   930         ==> ... ==> P
   931 
   932     for predicates and
   933 
   934       (x_1, ..., x_n) : s z_1 ... z_m ==>
   935         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   936         ==> ... ==> P
   937 
   938     for sets rather than
   939 
   940       x : s z_1 ... z_m ==>
   941         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
   942         ==> ... ==> P
   943 
   944     This may require terms in goals to be expanded to n-tuples
   945     (e.g. using case_tac or simplification with the split_paired_all
   946     rule) before the above elimination rule is applicable.
   947 
   948   - The elimination or case analysis rules for (mutually) inductive
   949     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
   950     list of rules "p_1_..._p_k.elims" is no longer available.
   951 
   952 * New package "function"/"fun" for general recursive functions,
   953 supporting mutual and nested recursion, definitions in local contexts,
   954 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
   955 for small examples, and the separate tutorial on the function
   956 package. The old recdef "package" is still available as before, but
   957 users are encouraged to use the new package.
   958 
   959 * Method "lexicographic_order" automatically synthesizes termination
   960 relations as lexicographic combinations of size measures. 
   961 
   962 * Case-expressions allow arbitrary constructor-patterns (including
   963 "_") and take their order into account, like in functional
   964 programming.  Internally, this is translated into nested
   965 case-expressions; missing cases are added and mapped to the predefined
   966 constant "undefined". In complicated cases printing may no longer show
   967 the original input but the internal form. Lambda-abstractions allow
   968 the same form of pattern matching: "% pat1 => e1 | ..." is an
   969 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
   970 variable.
   971 
   972 * IntDef: The constant "int :: nat => int" has been removed; now "int"
   973 is an abbreviation for "of_nat :: nat => int". The simplification
   974 rules for "of_nat" have been changed to work like "int" did
   975 previously.  Potential INCOMPATIBILITY:
   976   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
   977   - of_nat_diff and of_nat_mult are no longer default simp rules
   978 
   979 * Method "algebra" solves polynomial equations over (semi)rings using
   980 Groebner bases. The (semi)ring structure is defined by locales and the
   981 tool setup depends on that generic context. Installing the method for
   982 a specific type involves instantiating the locale and possibly adding
   983 declarations for computation on the coefficients.  The method is
   984 already instantiated for natural numbers and for the axiomatic class
   985 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
   986 CALCULEMUS 2007 for the general principles underlying this
   987 architecture of context-aware proof-tools.
   988 
   989 * Method "ferrack" implements quantifier elimination over
   990 special-purpose dense linear orders using locales (analogous to
   991 "algebra"). The method is already installed for class
   992 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
   993 rat, etc.
   994 
   995 * Former constant "List.op @" now named "List.append".  Use ML
   996 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
   997 circumvent possible incompatibilities when working on ML level.
   998 
   999 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1000 
  1001 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1002 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1003 
  1004 * New syntax for Haskell-like list comprehension (input only), eg.
  1005 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1006 
  1007 * The special syntax for function "filter" has changed from [x :
  1008 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1009 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1010 
  1011 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1012 defined on nat only, as an abbreviation for [a..<Suc b]
  1013 INCOMPATIBILITY.
  1014 
  1015 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1016 
  1017 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1018 
  1019 * New lemma collection field_simps (an extension of ring_simps) for
  1020 manipulating (in)equations involving division. Multiplies with all
  1021 denominators that can be proved to be non-zero (in equations) or
  1022 positive/negative (in inequations).
  1023 
  1024 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1025 have been improved and renamed to ring_simps, group_simps and
  1026 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1027 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1028 
  1029 * Theory Library/Commutative_Ring: switched from recdef to function
  1030 package; constants add, mul, pow now curried.  Infix syntax for
  1031 algebraic operations.
  1032 
  1033 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1034 INCOMPATIBILITY.
  1035 
  1036 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1037 INCOMPATIBILITY.
  1038 
  1039 * HOL/records: generalised field-update to take a function on the
  1040 field rather than the new value: r(|A := x|) is translated to A_update
  1041 (K x) r The K-combinator that is internally used is called K_record.
  1042 INCOMPATIBILITY: Usage of the plain update functions has to be
  1043 adapted.
  1044  
  1045 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1046 * x = 0, which are required for a semiring.  Richer structures do not
  1047 inherit from semiring_0 anymore, because this property is a theorem
  1048 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1049 there is more to prove, but this is mostly trivial.
  1050 
  1051 * Class "recpower" is generalized to arbitrary monoids, not just
  1052 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1053 commutativity or semiring properties additionally.
  1054 
  1055 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1056 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1057 better use 'abbreviation'.
  1058 
  1059 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1060 
  1061 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1062 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1063 significant changes for setting up numeral syntax for types:
  1064   - New constants Numeral.pred and Numeral.succ instead
  1065       of former Numeral.bin_pred and Numeral.bin_succ.
  1066   - Use integer operations instead of bin_add, bin_mult and so on.
  1067   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1068   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1069 
  1070 See src/HOL/Integ/IntArith.thy for an example setup.
  1071 
  1072 * Command 'normal_form' computes the normal form of a term that may
  1073 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1074 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1075 heavy-duty computations because the functions are compiled to ML
  1076 first.  Correspondingly, a method "normalization" is provided.  See
  1077 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1078 
  1079 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1080 25 like -->); output depends on the "iff" print_mode, the default is
  1081 "A = B" (with priority 50).
  1082 
  1083 * Relations less (<) and less_eq (<=) are also available on type bool.
  1084 Modified syntax to disallow nesting without explicit parentheses,
  1085 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1086 INCOMPATIBILITY.
  1087 
  1088 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1089 
  1090 * Relation composition operator "op O" now has precedence 75 and binds
  1091 stronger than union and intersection. INCOMPATIBILITY.
  1092 
  1093 * The old set interval syntax "{m..n(}" (and relatives) has been
  1094 removed.  Use "{m..<n}" (and relatives) instead.
  1095 
  1096 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1097 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1098 ``declare [[simproc del: neq]]''.
  1099 
  1100 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1101 True/False.
  1102 
  1103 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1104 
  1105 * Theorem setsum_mult renamed to setsum_right_distrib.
  1106 
  1107 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1108 ``rule'' method.
  1109 
  1110 * Reimplemented methods "sat" and "satx", with several improvements:
  1111 goals no longer need to be stated as "<prems> ==> False", equivalences
  1112 (i.e. "=" on type bool) are handled, variable names of the form
  1113 "lit_<n>" are no longer reserved, significant speedup.
  1114 
  1115 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1116 zChaff is still supported as well.
  1117 
  1118 * 'inductive' and 'datatype': provide projections of mutual rules,
  1119 bundled as foo_bar.inducts;
  1120 
  1121 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1122 Library.
  1123 
  1124 * Library: moved theory Accessible_Part to main HOL.
  1125 
  1126 * Library: added theory Coinductive_List of potentially infinite lists
  1127 as greatest fixed-point.
  1128 
  1129 * Library: added theory AssocList which implements (finite) maps as
  1130 association lists.
  1131 
  1132 * Method "evaluation" solves goals (i.e. a boolean expression)
  1133 efficiently by compiling it to ML.  The goal is "proved" (via an
  1134 oracle) if it evaluates to True.
  1135 
  1136 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1137 also when invoked by the simplifier.  This results in the Simplifier
  1138 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1139 Configuration option fast_arith_split_limit=0 recovers the old
  1140 behavior.
  1141 
  1142 * Support for hex (0x20) and binary (0b1001) numerals.
  1143 
  1144 * New method: reify eqs (t), where eqs are equations for an
  1145 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1146 parameter, computes a term s::'b and a list xs::'a list and proves the
  1147 theorem I xs s = t. This is also known as reification or quoting. The
  1148 resulting theorem is applied to the subgoal to substitute t with I xs
  1149 s.  If t is omitted, the subgoal itself is reified.
  1150 
  1151 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1152 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1153 where f is supposed to be a computable function (in the sense of code
  1154 generattion). The method uses reify to compute s and xs as above then
  1155 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1156 r and finally gets the theorem t = r, which is again applied to the
  1157 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1158 
  1159 * Reflection: Automatic reification now handels binding, an example is
  1160 available in src/HOL/ex/ReflectionEx.thy
  1161 
  1162 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1163 command 'statespace' that is similar to 'record', but introduces an
  1164 abstract specification based on the locale infrastructure instead of
  1165 HOL types.  This leads to extra flexibility in composing state spaces,
  1166 in particular multiple inheritance and renaming of components.
  1167 
  1168 
  1169 *** HOL-Complex ***
  1170 
  1171 * Hyperreal: Functions root and sqrt are now defined on negative real
  1172 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1173 Nonnegativity side conditions have been removed from many lemmas, so
  1174 that more subgoals may now be solved by simplification; potential
  1175 INCOMPATIBILITY.
  1176 
  1177 * Real: new type classes formalize real normed vector spaces and
  1178 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1179 and norm :: 'a => real.
  1180 
  1181 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1182 reals into other types. The overloaded constant Reals :: 'a set is now
  1183 defined as range of_real; potential INCOMPATIBILITY.
  1184 
  1185 * Real: proper support for ML code generation, including 'quickcheck'.
  1186 Reals are implemented as arbitrary precision rationals.
  1187 
  1188 * Hyperreal: Several constants that previously worked only for the
  1189 reals have been generalized, so they now work over arbitrary vector
  1190 spaces. Type annotations may need to be added in some cases; potential
  1191 INCOMPATIBILITY.
  1192 
  1193   Infinitesimal  :: ('a::real_normed_vector) star set
  1194   HFinite        :: ('a::real_normed_vector) star set
  1195   HInfinite      :: ('a::real_normed_vector) star set
  1196   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1197   monad          :: ('a::real_normed_vector) star => 'a star set
  1198   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1199   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1200   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1201   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1202   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1203   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1204   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1205   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1206   sgn            :: 'a::real_normed_vector => 'a
  1207   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1208 
  1209 * Complex: Some complex-specific constants are now abbreviations for
  1210 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1211 hnorm.  Other constants have been entirely removed in favor of the
  1212 polymorphic versions (INCOMPATIBILITY):
  1213 
  1214   approx        <-- capprox
  1215   HFinite       <-- CFinite
  1216   HInfinite     <-- CInfinite
  1217   Infinitesimal <-- CInfinitesimal
  1218   monad         <-- cmonad
  1219   galaxy        <-- cgalaxy
  1220   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1221   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1222   (ns)deriv     <-- (ns)cderiv
  1223 
  1224 
  1225 *** HOL-Algebra ***
  1226 
  1227 * Formalisation of ideals and the quotient construction over rings.
  1228 
  1229 * Order and lattice theory no longer based on records.
  1230 INCOMPATIBILITY.
  1231 
  1232 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1233 greatest_closed.  INCOMPATIBILITY.
  1234 
  1235 * Method algebra is now set up via an attribute.  For examples see
  1236 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1237 of algebraic structures.
  1238 
  1239 * Renamed theory CRing to Ring.
  1240 
  1241 
  1242 *** HOL-Nominal ***
  1243 
  1244 * Substantial, yet incomplete support for nominal datatypes (binding
  1245 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  1246 src/HOL/Nominal/Examples.  Prospective users should consult
  1247 http://isabelle.in.tum.de/nominal/
  1248 
  1249 
  1250 *** ML ***
  1251 
  1252 * ML basics: just one true type int, which coincides with IntInf.int
  1253 (even on SML/NJ).
  1254 
  1255 * ML within Isar: antiquotations allow to embed statically-checked
  1256 formal entities in the source, referring to the context available at
  1257 compile-time.  For example:
  1258 
  1259 ML {* @{sort "{zero,one}"} *}
  1260 ML {* @{typ "'a => 'b"} *}
  1261 ML {* @{term "%x. x"} *}
  1262 ML {* @{prop "x == y"} *}
  1263 ML {* @{ctyp "'a => 'b"} *}
  1264 ML {* @{cterm "%x. x"} *}
  1265 ML {* @{cprop "x == y"} *}
  1266 ML {* @{thm asm_rl} *}
  1267 ML {* @{thms asm_rl} *}
  1268 ML {* @{type_name c} *}
  1269 ML {* @{type_syntax c} *}
  1270 ML {* @{const_name c} *}
  1271 ML {* @{const_syntax c} *}
  1272 ML {* @{context} *}
  1273 ML {* @{theory} *}
  1274 ML {* @{theory Pure} *}
  1275 ML {* @{theory_ref} *}
  1276 ML {* @{theory_ref Pure} *}
  1277 ML {* @{simpset} *}
  1278 ML {* @{claset} *}
  1279 ML {* @{clasimpset} *}
  1280 
  1281 The same works for sources being ``used'' within an Isar context.
  1282 
  1283 * ML in Isar: improved error reporting; extra verbosity with
  1284 ML_Context.trace enabled.
  1285 
  1286 * Pure/General/table.ML: the join operations now works via exceptions
  1287 DUP/SAME instead of type option. This is simpler in simple cases, and
  1288 admits slightly more efficient complex applications.
  1289 
  1290 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1291 use Context.generic instead of just theory.
  1292 
  1293 * Pure: datatype Context.generic joins theory/Proof.context and
  1294 provides some facilities for code that works in either kind of
  1295 context, notably GenericDataFun for uniform theory and proof data.
  1296 
  1297 * Pure: simplified internal attribute type, which is now always
  1298 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  1299 local (Proof.context) attributes have been discontinued, while
  1300 minimizing code duplication. Thm.rule_attribute and
  1301 Thm.declaration_attribute build canonical attributes; see also structure
  1302 Context for further operations on Context.generic, notably
  1303 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  1304 declarations and definitions.
  1305 
  1306 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1307 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1308 init only required for impure data. INCOMPATIBILITY: empty really need
  1309 to be empty (no dependencies on theory content!)
  1310 
  1311 * Pure/kernel: consts certification ignores sort constraints given in
  1312 signature declarations. (This information is not relevant to the
  1313 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  1314 potential INCOMPATIBILITY.
  1315 
  1316 * Pure: axiomatic type classes are now purely definitional, with
  1317 explicit proofs of class axioms and super class relations performed
  1318 internally. See Pure/axclass.ML for the main internal interfaces --
  1319 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1320 AxClass.axiomatize_class/classrel/arity supersede
  1321 Sign.add_classes/classrel/arities.
  1322 
  1323 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1324 global/local versions on theory vs. Proof.context have been
  1325 discontinued; Attrib.syntax and Method.syntax have been adapted
  1326 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1327 attributes, methods, etc.
  1328 
  1329 * Pure: several functions of signature "... -> theory -> theory * ..."
  1330 have been reoriented to "... -> theory -> ... * theory" in order to
  1331 allow natural usage in combination with the ||>, ||>>, |-> and
  1332 fold_map combinators.
  1333 
  1334 * Pure: official theorem names (closed derivations) and additional
  1335 comments (tags) are now strictly separate.  Name hints -- which are
  1336 maintained as tags -- may be attached any time without affecting the
  1337 derivation.
  1338 
  1339 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1340 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1341 achieve the old behaviour.
  1342 
  1343 * Pure: the "Goal" constant is now called "prop", supporting a
  1344 slightly more general idea of ``protecting'' meta-level rule
  1345 statements.
  1346 
  1347 * Pure: Logic.(un)varify only works in a global context, which is now
  1348 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1349 Logic.legacy_(un)varify as temporary workaround.
  1350 
  1351 * Pure: structure Name provides scalable operations for generating
  1352 internal variable names, notably Name.variants etc.  This replaces
  1353 some popular functions from term.ML:
  1354 
  1355   Term.variant		->  Name.variant
  1356   Term.variantlist	->  Name.variant_list
  1357   Term.invent_names	->  Name.invent_list
  1358 
  1359 Note that low-level renaming rarely occurs in new code -- operations
  1360 from structure Variable are used instead (see below).
  1361 
  1362 * Pure: structure Variable provides fundamental operations for proper
  1363 treatment of fixed/schematic variables in a context.  For example,
  1364 Variable.import introduces fixes for schematics of given facts and
  1365 Variable.export reverses the effect (up to renaming) -- this replaces
  1366 various freeze_thaw operations.
  1367 
  1368 * Pure: structure Goal provides simple interfaces for
  1369 init/conclude/finish and tactical prove operations (replacing former
  1370 Tactic.prove).  Goal.prove is the canonical way to prove results
  1371 within a given context; Goal.prove_global is a degraded version for
  1372 theory level goals, including a global Drule.standard.  Note that
  1373 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1374 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1375 in a locale context).
  1376 
  1377 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  1378 and type checking (Syntax.check_term etc.), with common combinations
  1379 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  1380 which are considered legacy and await removal.
  1381 
  1382 * Pure/Syntax: generic interfaces for type unchecking
  1383 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  1384 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  1385 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  1386 available for convenience, but refer to the very same operations using
  1387 a mere theory instead of a full context.
  1388 
  1389 * Isar: simplified treatment of user-level errors, using exception
  1390 ERROR of string uniformly.  Function error now merely raises ERROR,
  1391 without any side effect on output channels.  The Isar toplevel takes
  1392 care of proper display of ERROR exceptions.  ML code may use plain
  1393 handle/can/try; cat_error may be used to concatenate errors like this:
  1394 
  1395   ... handle ERROR msg => cat_error msg "..."
  1396 
  1397 Toplevel ML code (run directly or through the Isar toplevel) may be
  1398 embedded into the Isar toplevel with exception display/debug like
  1399 this:
  1400 
  1401   Isar.toplevel (fn () => ...)
  1402 
  1403 INCOMPATIBILITY, removed special transform_error facilities, removed
  1404 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1405 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1406 -- use plain ERROR instead.
  1407 
  1408 * Isar: theory setup now has type (theory -> theory), instead of a
  1409 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1410 
  1411 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  1412 ProofContext.debug/verbose flags.
  1413 
  1414 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1415 theory before entering a proof state.  Transactions now always see a
  1416 quasi-functional intermediate checkpoint, both in interactive and
  1417 batch mode.
  1418 
  1419 * Isar: simplified interfaces for outer syntax.  Renamed
  1420 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  1421 OuterSyntax.add_parsers -- this functionality is now included in
  1422 OuterSyntax.command etc.  INCOMPATIBILITY.
  1423 
  1424 * Simplifier: the simpset of a running simplification process now
  1425 contains a proof context (cf. Simplifier.the_context), which is the
  1426 very context that the initial simpset has been retrieved from (by
  1427 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1428 (solver, looper etc.) may depend on arbitrary proof data.
  1429 
  1430 * Simplifier.inherit_context inherits the proof context (plus the
  1431 local bounds) of the current simplification process; any simproc
  1432 etc. that calls the Simplifier recursively should do this!  Removed
  1433 former Simplifier.inherit_bounds, which is already included here --
  1434 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1435 specify an explicit context using Simplifier.context/theory_context.
  1436 
  1437 * Simplifier/Classical Reasoner: more abstract interfaces
  1438 change_simpset/claset for modifying the simpset/claset reference of a
  1439 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1440 INCOMPATIBILITY.
  1441 
  1442 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1443 "Trueprop" etc.
  1444 
  1445 
  1446 *** System ***
  1447 
  1448 * settings: the default heap location within ISABELLE_HOME_USER now
  1449 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  1450 Isabelle installations.
  1451 
  1452 * isabelle-process: option -S (secure mode) disables some critical
  1453 operations, notably runtime compilation and evaluation of ML source
  1454 code.
  1455 
  1456 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  1457 
  1458 * Support for parallel execution, using native multicore support of
  1459 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  1460 independent theories, according to the given theory header
  1461 specifications. The maximum number of worker threads is specified via
  1462 usedir option -M or the "max-threads" setting in Proof General. A
  1463 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  1464 to 6 on a 8-core machine.  User-code needs to observe certain
  1465 guidelines for thread-safe programming, see appendix A in the Isar
  1466 Implementation manual.
  1467 
  1468 
  1469 
  1470 New in Isabelle2005 (October 2005)
  1471 ----------------------------------
  1472 
  1473 *** General ***
  1474 
  1475 * Theory headers: the new header syntax for Isar theories is
  1476 
  1477   theory <name>
  1478   imports <theory1> ... <theoryN>
  1479   uses <file1> ... <fileM>
  1480   begin
  1481 
  1482 where the 'uses' part is optional.  The previous syntax
  1483 
  1484   theory <name> = <theory1> + ... + <theoryN>:
  1485 
  1486 will disappear in the next release.  Use isatool fixheaders to convert
  1487 existing theory files.  Note that there is no change in ancient
  1488 non-Isar theories now, but these will disappear soon.
  1489 
  1490 * Theory loader: parent theories can now also be referred to via
  1491 relative and absolute paths.
  1492 
  1493 * Command 'find_theorems' searches for a list of criteria instead of a
  1494 list of constants. Known criteria are: intro, elim, dest, name:string,
  1495 simp:term, and any term. Criteria can be preceded by '-' to select
  1496 theorems that do not match. Intro, elim, dest select theorems that
  1497 match the current goal, name:s selects theorems whose fully qualified
  1498 name contain s, and simp:term selects all simplification rules whose
  1499 lhs match term.  Any other term is interpreted as pattern and selects
  1500 all theorems matching the pattern. Available in ProofGeneral under
  1501 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1502 
  1503   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1504 
  1505 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1506 matching the current goal as introduction rule and not having "HOL."
  1507 in their name (i.e. not being defined in theory HOL).
  1508 
  1509 * Command 'thms_containing' has been discontinued in favour of
  1510 'find_theorems'; INCOMPATIBILITY.
  1511 
  1512 * Communication with Proof General is now 8bit clean, which means that
  1513 Unicode text in UTF-8 encoding may be used within theory texts (both
  1514 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1515 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1516 
  1517   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1518   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1519 
  1520 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1521 Classical Reasoner.  Typical big applications run around 2 times
  1522 faster.
  1523 
  1524 
  1525 *** Document preparation ***
  1526 
  1527 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1528 of raw sources.  Only those symbols that do not require additional
  1529 LaTeX packages (depending on comments in isabellesym.sty) are
  1530 displayed properly, everything else is left verbatim.  isatool display
  1531 and isatool print are used as front ends (these are subject to the
  1532 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1533 
  1534 * Command tags control specific markup of certain regions of text,
  1535 notably folding and hiding.  Predefined tags include "theory" (for
  1536 theory begin and end), "proof" for proof commands, and "ML" for
  1537 commands involving ML code; the additional tags "visible" and
  1538 "invisible" are unused by default.  Users may give explicit tag
  1539 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1540 interpretation of tags is determined by the LaTeX job during document
  1541 preparation: see option -V of isatool usedir, or options -n and -t of
  1542 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1543 \isadroptag.
  1544 
  1545 Several document versions may be produced at the same time via isatool
  1546 usedir (the generated index.html will link all of them).  Typical
  1547 specifications include ''-V document=theory,proof,ML'' to present
  1548 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1549 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1550 these parts without any formal replacement text.  The Isabelle site
  1551 default settings produce ''document'' and ''outline'' versions as
  1552 specified above.
  1553 
  1554 * Several new antiquotations:
  1555 
  1556   @{term_type term} prints a term with its type annotated;
  1557 
  1558   @{typeof term} prints the type of a term;
  1559 
  1560   @{const const} is the same as @{term const}, but checks that the
  1561   argument is a known logical constant;
  1562 
  1563   @{term_style style term} and @{thm_style style thm} print a term or
  1564   theorem applying a "style" to it
  1565 
  1566   @{ML text}
  1567 
  1568 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1569 definitions, equations, inequations etc., 'concl' printing only the
  1570 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1571 to print the specified premise.  TermStyle.add_style provides an ML
  1572 interface for introducing further styles.  See also the "LaTeX Sugar"
  1573 document practical applications.  The ML antiquotation prints
  1574 type-checked ML expressions verbatim.
  1575 
  1576 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1577 and 'text' support optional locale specification '(in loc)', which
  1578 specifies the default context for interpreting antiquotations.  For
  1579 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1580 
  1581 * Option 'locale=NAME' of antiquotations specifies an alternative
  1582 context interpreting the subsequent argument.  For example: @{thm
  1583 [locale=lattice] inf_assoc}.
  1584 
  1585 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1586 a proof context.
  1587 
  1588 * Proper output of antiquotations for theory commands involving a
  1589 proof context (such as 'locale' or 'theorem (in loc) ...').
  1590 
  1591 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1592 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1593 
  1594 * isatool usedir: new option -C (default true) controls whether option
  1595 -D should include a copy of the original document directory; -C false
  1596 prevents unwanted effects such as copying of administrative CVS data.
  1597 
  1598 
  1599 *** Pure ***
  1600 
  1601 * Considerably improved version of 'constdefs' command.  Now performs
  1602 automatic type-inference of declared constants; additional support for
  1603 local structure declarations (cf. locales and HOL records), see also
  1604 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1605 sequential dependencies of definitions within a single 'constdefs'
  1606 section; moreover, the declared name needs to be an identifier.  If
  1607 all fails, consider to fall back on 'consts' and 'defs' separately.
  1608 
  1609 * Improved indexed syntax and implicit structures.  First of all,
  1610 indexed syntax provides a notational device for subscripted
  1611 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1612 expressions.  Secondly, in a local context with structure
  1613 declarations, number indexes \<^sub>n or the empty index (default
  1614 number 1) refer to a certain fixed variable implicitly; option
  1615 show_structs controls printing of implicit structures.  Typical
  1616 applications of these concepts involve record types and locales.
  1617 
  1618 * New command 'no_syntax' removes grammar declarations (and
  1619 translations) resulting from the given syntax specification, which is
  1620 interpreted in the same manner as for the 'syntax' command.
  1621 
  1622 * 'Advanced' translation functions (parse_translation etc.) may depend
  1623 on the signature of the theory context being presently used for
  1624 parsing/printing, see also isar-ref manual.
  1625 
  1626 * Improved 'oracle' command provides a type-safe interface to turn an
  1627 ML expression of type theory -> T -> term into a primitive rule of
  1628 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1629 is already included here); see also FOL/ex/IffExample.thy;
  1630 INCOMPATIBILITY.
  1631 
  1632 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1633 before); "cI" is no longer bound, use "c.intro" instead.
  1634 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1635 axclasses vs. locales.
  1636 
  1637 * Improved internal renaming of symbolic identifiers -- attach primes
  1638 instead of base 26 numbers.
  1639 
  1640 * New flag show_question_marks controls printing of leading question
  1641 marks in schematic variable names.
  1642 
  1643 * In schematic variable names, *any* symbol following \<^isub> or
  1644 \<^isup> is now treated as part of the base name.  For example, the
  1645 following works without printing of awkward ".0" indexes:
  1646 
  1647   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1648     by simp
  1649 
  1650 * Inner syntax includes (*(*nested*) comments*).
  1651 
  1652 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1653 annotations as "(00...)".
  1654 
  1655 * Clear separation of logical types and nonterminals, where the latter
  1656 may only occur in 'syntax' specifications or type abbreviations.
  1657 Before that distinction was only partially implemented via type class
  1658 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1659 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1660 exotic syntax specifications may require further adaption
  1661 (e.g. Cube/Cube.thy).
  1662 
  1663 * Removed obsolete type class "logic", use the top sort {} instead.
  1664 Note that non-logical types should be declared as 'nonterminals'
  1665 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1666 specifications.
  1667 
  1668 * Attributes 'induct' and 'cases': type or set names may now be
  1669 locally fixed variables as well.
  1670 
  1671 * Simplifier: can now control the depth to which conditional rewriting
  1672 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1673 Limit.
  1674 
  1675 * Simplifier: simplification procedures may now take the current
  1676 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1677 interface), which is very useful for calling the Simplifier
  1678 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1679 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1680 low-level mk_simproc no longer applies Logic.varify internally, to
  1681 allow for use in a context of fixed variables.
  1682 
  1683 * thin_tac now works even if the assumption being deleted contains !!
  1684 or ==>.  More generally, erule now works even if the major premise of
  1685 the elimination rule contains !! or ==>.
  1686 
  1687 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1688 
  1689 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1690 from Pure, which contains all common declarations already.  Both
  1691 theories are defined via plain Isabelle/Isar .thy files.
  1692 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1693 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1694 use isatool fixcpure to adapt your theory and ML sources.
  1695 
  1696 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1697 selections of theorems in named facts via index ranges.
  1698 
  1699 * 'print_theorems': in theory mode, really print the difference
  1700 wrt. the last state (works for interactive theory development only),
  1701 in proof mode print all local facts (cf. 'print_facts');
  1702 
  1703 * 'hide': option '(open)' hides only base names.
  1704 
  1705 * More efficient treatment of intermediate checkpoints in interactive
  1706 theory development.
  1707 
  1708 * Code generator is now invoked via code_module (incremental code
  1709 generation) and code_library (modular code generation, ML structures
  1710 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1711 must be quoted when used as identifiers.
  1712 
  1713 * New 'value' command for reading, evaluating and printing terms using
  1714 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1715 quoted when used as identifier.
  1716 
  1717 
  1718 *** Locales ***
  1719 
  1720 * New commands for the interpretation of locale expressions in
  1721 theories (1), locales (2) and proof contexts (3).  These generate
  1722 proof obligations from the expression specification.  After the
  1723 obligations have been discharged, theorems of the expression are added
  1724 to the theory, target locale or proof context.  The synopsis of the
  1725 commands is a follows:
  1726 
  1727   (1) interpretation expr inst
  1728   (2) interpretation target < expr
  1729   (3) interpret expr inst
  1730 
  1731 Interpretation in theories and proof contexts require a parameter
  1732 instantiation of terms from the current context.  This is applied to
  1733 specifications and theorems of the interpreted expression.
  1734 Interpretation in locales only permits parameter renaming through the
  1735 locale expression.  Interpretation is smart in that interpretations
  1736 that are active already do not occur in proof obligations, neither are
  1737 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1738 inspect active interpretations of a particular locale.  For details,
  1739 see the Isar Reference manual.  Examples can be found in
  1740 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1741 
  1742 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1743 'interpret' instead.
  1744 
  1745 * New context element 'constrains' for adding type constraints to
  1746 parameters.
  1747 
  1748 * Context expressions: renaming of parameters with syntax
  1749 redeclaration.
  1750 
  1751 * Locale declaration: 'includes' disallowed.
  1752 
  1753 * Proper static binding of attribute syntax -- i.e. types / terms /
  1754 facts mentioned as arguments are always those of the locale definition
  1755 context, independently of the context of later invocations.  Moreover,
  1756 locale operations (renaming and type / term instantiation) are applied
  1757 to attribute arguments as expected.
  1758 
  1759 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1760 actual attributes; rare situations may require Attrib.attribute to
  1761 embed those attributes into Attrib.src that lack concrete syntax.
  1762 Attribute implementations need to cooperate properly with the static
  1763 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1764 Attrib.XXX_thm etc. already do the right thing without further
  1765 intervention.  Only unusual applications -- such as "where" or "of"
  1766 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1767 on the context and the facts involved -- may have to assign parsed
  1768 values to argument tokens explicitly.
  1769 
  1770 * Changed parameter management in theorem generation for long goal
  1771 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1772 theorem statement in rare situations.
  1773 
  1774 * Locale inspection command 'print_locale' omits notes elements.  Use
  1775 'print_locale!' to have them included in the output.
  1776 
  1777 
  1778 *** Provers ***
  1779 
  1780 * Provers/hypsubst.ML: improved version of the subst method, for
  1781 single-step rewriting: it now works in bound variable contexts. New is
  1782 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1783 rewrite a different subterm than the original subst method, which is
  1784 still available as 'simplesubst'.
  1785 
  1786 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1787 and quasi orders.
  1788 
  1789 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1790 reflexive-transitive closure of relations.
  1791 
  1792 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1793 limit (previously hard-coded with a value of 20) user-definable.
  1794 
  1795 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1796 is peformed already.  Object-logics merely need to finish their
  1797 initial simpset configuration as before.  INCOMPATIBILITY.
  1798 
  1799 
  1800 *** HOL ***
  1801 
  1802 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1803 
  1804   syntax (epsilon)
  1805     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1806 
  1807 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1808 and x-symbol; use option '-m epsilon' to get it actually printed.
  1809 Moreover, the mathematically important symbolic identifier \<epsilon>
  1810 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1811 
  1812 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1813 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1814 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1815 support corresponding Isar calculations.
  1816 
  1817 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1818 instead of ":".
  1819 
  1820 * theory SetInterval: changed the syntax for open intervals:
  1821 
  1822   Old       New
  1823   {..n(}    {..<n}
  1824   {)n..}    {n<..}
  1825   {m..n(}   {m..<n}
  1826   {)m..n}   {m<..n}
  1827   {)m..n(}  {m<..<n}
  1828 
  1829 The old syntax is still supported but will disappear in the next
  1830 release.  For conversion use the following Emacs search and replace
  1831 patterns (these are not perfect but work quite well):
  1832 
  1833   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1834   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1835 
  1836 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1837 equalities in commutative rings; method 'algebra' provides a generic
  1838 interface.
  1839 
  1840 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1841 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1842 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1843 be a tuple pattern.
  1844 
  1845 Some new syntax forms are available:
  1846 
  1847   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1848   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1849   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1850   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1851 
  1852 The latter form "\<Sum>x < k. e" used to be based on a separate
  1853 function "Summation", which has been discontinued.
  1854 
  1855 * theory Finite_Set: in structured induction proofs, the insert case
  1856 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1857 (insert F x)'.
  1858 
  1859 * The 'refute' command has been extended to support a much larger
  1860 fragment of HOL, including axiomatic type classes, constdefs and
  1861 typedefs, inductive datatypes and recursion.
  1862 
  1863 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1864 Requires zChaff with proof generation to be installed.  See
  1865 HOL/ex/SAT_Examples.thy for examples.
  1866 
  1867 * Datatype induction via method 'induct' now preserves the name of the
  1868 induction variable. For example, when proving P(xs::'a list) by
  1869 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1870 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1871 in unstructured proof scripts.
  1872 
  1873 * Reworked implementation of records.  Improved scalability for
  1874 records with many fields, avoiding performance problems for type
  1875 inference. Records are no longer composed of nested field types, but
  1876 of nested extension types. Therefore the record type only grows linear
  1877 in the number of extensions and not in the number of fields.  The
  1878 top-level (users) view on records is preserved.  Potential
  1879 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1880 old record representation. The type generated for a record is called
  1881 <record_name>_ext_type.
  1882 
  1883 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1884 proofs triggered by a record definition or a simproc (if
  1885 quick_and_dirty is enabled).  Definitions of large records can take
  1886 quite long.
  1887 
  1888 New simproc record_upd_simproc for simplification of multiple record
  1889 updates enabled by default.  Moreover, trivial updates are also
  1890 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1891 occasionally, since simplification is more powerful by default.
  1892 
  1893 * typedef: proper support for polymorphic sets, which contain extra
  1894 type-variables in the term.
  1895 
  1896 * Simplifier: automatically reasons about transitivity chains
  1897 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1898 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1899 old proofs break occasionally as simplification may now solve more
  1900 goals than previously.
  1901 
  1902 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1903 present.  Works for all partial orders (class "order"), in particular
  1904 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1905 just like y <= x.
  1906 
  1907 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1908 bound variable or a constant then the let is unfolded.  Otherwise
  1909 first a is simplified to b, and then f b is simplified to g. If
  1910 possible we abstract b from g arriving at "let x = b in h x",
  1911 otherwise we unfold the let and arrive at g.  The simproc can be
  1912 enabled/disabled by the reference use_let_simproc.  Potential
  1913 INCOMPATIBILITY since simplification is more powerful by default.
  1914 
  1915 * Classical reasoning: the meson method now accepts theorems as arguments.
  1916 
  1917 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1918 jobs to provide advice on the provability of subgoals.
  1919 
  1920 * Theory OrderedGroup and Ring_and_Field: various additions and
  1921 improvements to faciliate calculations involving equalities and
  1922 inequalities.
  1923 
  1924 The following theorems have been eliminated or modified
  1925 (INCOMPATIBILITY):
  1926 
  1927   abs_eq             now named abs_of_nonneg
  1928   abs_of_ge_0        now named abs_of_nonneg
  1929   abs_minus_eq       now named abs_of_nonpos
  1930   imp_abs_id         now named abs_of_nonneg
  1931   imp_abs_neg_id     now named abs_of_nonpos
  1932   mult_pos           now named mult_pos_pos
  1933   mult_pos_le        now named mult_nonneg_nonneg
  1934   mult_pos_neg_le    now named mult_nonneg_nonpos
  1935   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1936   mult_neg           now named mult_neg_neg
  1937   mult_neg_le        now named mult_nonpos_nonpos
  1938 
  1939 * The following lemmas in Ring_and_Field have been added to the simplifier:
  1940      
  1941      zero_le_square
  1942      not_square_less_zero 
  1943 
  1944   The following lemmas have been deleted from Real/RealPow:
  1945   
  1946      realpow_zero_zero
  1947      realpow_two
  1948      realpow_less
  1949      zero_le_power
  1950      realpow_two_le
  1951      abs_realpow_two
  1952      realpow_two_abs     
  1953 
  1954 * Theory Parity: added rules for simplifying exponents.
  1955 
  1956 * Theory List:
  1957 
  1958 The following theorems have been eliminated or modified
  1959 (INCOMPATIBILITY):
  1960 
  1961   list_all_Nil       now named list_all.simps(1)
  1962   list_all_Cons      now named list_all.simps(2)
  1963   list_all_conv      now named list_all_iff
  1964   set_mem_eq         now named mem_iff
  1965 
  1966 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1967 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1968 
  1969 
  1970 *** HOL-Complex ***
  1971 
  1972 * Theory RealDef: better support for embedding natural numbers and
  1973 integers in the reals.
  1974 
  1975 The following theorems have been eliminated or modified
  1976 (INCOMPATIBILITY):
  1977 
  1978   exp_ge_add_one_self  now requires no hypotheses
  1979   real_of_int_add      reversed direction of equality (use [symmetric])
  1980   real_of_int_minus    reversed direction of equality (use [symmetric])
  1981   real_of_int_diff     reversed direction of equality (use [symmetric])
  1982   real_of_int_mult     reversed direction of equality (use [symmetric])
  1983 
  1984 * Theory RComplete: expanded support for floor and ceiling functions.
  1985 
  1986 * Theory Ln is new, with properties of the natural logarithm
  1987 
  1988 * Hyperreal: There is a new type constructor "star" for making
  1989 nonstandard types.  The old type names are now type synonyms:
  1990 
  1991   hypreal = real star
  1992   hypnat = nat star
  1993   hcomplex = complex star
  1994 
  1995 * Hyperreal: Many groups of similarly-defined constants have been
  1996 replaced by polymorphic versions (INCOMPATIBILITY):
  1997 
  1998   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1999 
  2000   starset      <-- starsetNat, starsetC
  2001   *s*          <-- *sNat*, *sc*
  2002   starset_n    <-- starsetNat_n, starsetC_n
  2003   *sn*         <-- *sNatn*, *scn*
  2004   InternalSets <-- InternalNatSets, InternalCSets
  2005 
  2006   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2007   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2008   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2009   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2010   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2011 
  2012 * Hyperreal: Many type-specific theorems have been removed in favor of
  2013 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2014 
  2015   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2016   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2017   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2018   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2019   right_minus <-- hypreal_add_minus
  2020   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2021   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2022   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2023   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2024   mult_1_right <-- hcomplex_mult_one_right
  2025   mult_zero_left <-- hcomplex_mult_zero_left
  2026   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2027   right_distrib <-- hypnat_add_mult_distrib2
  2028   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2029   right_inverse <-- hypreal_mult_inverse
  2030   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2031   order_refl <-- {hypreal,hypnat}_le_refl
  2032   order_trans <-- {hypreal,hypnat}_le_trans
  2033   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2034   order_less_le <-- {hypreal,hypnat}_less_le
  2035   linorder_linear <-- {hypreal,hypnat}_le_linear
  2036   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2037   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2038   add_nonneg_nonneg <-- hypreal_le_add_order
  2039 
  2040 * Hyperreal: Separate theorems having to do with type-specific
  2041 versions of constants have been merged into theorems that apply to the
  2042 new polymorphic constants (INCOMPATIBILITY):
  2043 
  2044   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2045   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2046   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2047   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2048   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2049   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2050   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2051   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2052   STAR_diff <-- {STAR,STARC}_diff
  2053   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2054     STARC_hcomplex_of_complex}_image_subset
  2055   starset_n_Un <-- starset{Nat,C}_n_Un
  2056   starset_n_Int <-- starset{Nat,C}_n_Int
  2057   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2058   starset_n_diff <-- starset{Nat,C}_n_diff
  2059   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2060   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2061   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2062   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2063   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2064   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2065   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2066   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2067   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2068   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2069   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2070   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2071   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2072   starfun_diff <-- starfun{C,RC,CR}_diff
  2073   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2074   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2075   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2076   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2077   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2078   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2079   starfun_Id <-- starfunC_Id
  2080   starfun_approx <-- starfun{Nat,CR}_approx
  2081   starfun_capprox <-- starfun{C,RC}_capprox
  2082   starfun_abs <-- starfunNat_rabs
  2083   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2084   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2085   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2086   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2087   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2088   starfun_add_approx <-- starfunCR_add_approx
  2089   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2090   starfun_divide <-- starfun{C,CR,RC}_divide
  2091   starfun_n <-- starfun{Nat,C}_n
  2092   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2093   starfun_n_add <-- starfun{Nat,C}_n_add
  2094   starfun_n_add_minus <-- starfunNat_n_add_minus
  2095   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2096   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2097   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2098 
  2099   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2100   star_n_minus <-- {hypreal,hcomplex}_minus
  2101   star_n_diff <-- {hypreal,hcomplex}_diff
  2102   star_n_mult <-- {hypreal,hcomplex}_mult
  2103   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2104   star_n_le <-- {hypreal,hypnat}_le
  2105   star_n_less <-- {hypreal,hypnat}_less
  2106   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2107   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2108   star_n_abs <-- hypreal_hrabs
  2109   star_n_divide <-- hcomplex_divide
  2110 
  2111   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2112   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2113   star_of_diff <-- hypreal_of_real_diff
  2114   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2115   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2116   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2117   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2118   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2119   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2120   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2121   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2122   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2123   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2124   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2125   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2126   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2127   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2128   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2129   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2130   star_of_power <-- hypreal_of_real_power
  2131   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2132 
  2133 * Hyperreal: new method "transfer" that implements the transfer
  2134 principle of nonstandard analysis. With a subgoal that mentions
  2135 nonstandard types like "'a star", the command "apply transfer"
  2136 replaces it with an equivalent one that mentions only standard types.
  2137 To be successful, all free variables must have standard types; non-
  2138 standard variables must have explicit universal quantifiers.
  2139 
  2140 * Hyperreal: A theory of Taylor series.
  2141 
  2142 
  2143 *** HOLCF ***
  2144 
  2145 * Discontinued special version of 'constdefs' (which used to support
  2146 continuous functions) in favor of the general Pure one with full
  2147 type-inference.
  2148 
  2149 * New simplification procedure for solving continuity conditions; it
  2150 is much faster on terms with many nested lambda abstractions (cubic
  2151 instead of exponential time).
  2152 
  2153 * New syntax for domain package: selector names are now optional.
  2154 Parentheses should be omitted unless argument is lazy, for example:
  2155 
  2156   domain 'a stream = cons "'a" (lazy "'a stream")
  2157 
  2158 * New command 'fixrec' for defining recursive functions with pattern
  2159 matching; defining multiple functions with mutual recursion is also
  2160 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2161 sinr, or any data constructor defined by the domain package. The given
  2162 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2163 syntax and examples.
  2164 
  2165 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2166 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2167 but the proof obligation additionally includes an admissibility
  2168 requirement. The packages generate instances of class cpo or pcpo,
  2169 with continuity and strictness theorems for Rep and Abs.
  2170 
  2171 * HOLCF: Many theorems have been renamed according to a more standard naming
  2172 scheme (INCOMPATIBILITY):
  2173 
  2174   foo_inject:  "foo$x = foo$y ==> x = y"
  2175   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2176   foo_less:    "(foo$x << foo$y) = (x << y)"
  2177   foo_strict:  "foo$UU = UU"
  2178   foo_defined: "... ==> foo$x ~= UU"
  2179   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2180 
  2181 
  2182 *** ZF ***
  2183 
  2184 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2185 including the First Isomorphism Theorem (on quotienting by the kernel
  2186 of a homomorphism).
  2187 
  2188 * ZF/Simplifier: install second copy of type solver that actually
  2189 makes use of TC rules declared to Isar proof contexts (or locales);
  2190 the old version is still required for ML proof scripts.
  2191 
  2192 
  2193 *** Cube ***
  2194 
  2195 * Converted to Isar theory format; use locales instead of axiomatic
  2196 theories.
  2197 
  2198 
  2199 *** ML ***
  2200 
  2201 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2202 for ||>, ||>>, |>>,
  2203 
  2204 * Pure/library.ML no longer defines its own option datatype, but uses
  2205 that of the SML basis, which has constructors NONE and SOME instead of
  2206 None and Some, as well as exception Option.Option instead of OPTION.
  2207 The functions the, if_none, is_some, is_none have been adapted
  2208 accordingly, while Option.map replaces apsome.
  2209 
  2210 * Pure/library.ML: the exception LIST has been given up in favour of
  2211 the standard exceptions Empty and Subscript, as well as
  2212 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2213 superceded by the standard hd and tl functions etc.
  2214 
  2215 A number of basic list functions are no longer exported to the ML
  2216 toplevel, as they are variants of predefined functions.  The following
  2217 suggests how one can translate existing code:
  2218 
  2219     rev_append xs ys = List.revAppend (xs, ys)
  2220     nth_elem (i, xs) = List.nth (xs, i)
  2221     last_elem xs = List.last xs
  2222     flat xss = List.concat xss
  2223     seq fs = List.app fs
  2224     partition P xs = List.partition P xs
  2225     mapfilter f xs = List.mapPartial f xs
  2226 
  2227 * Pure/library.ML: several combinators for linear functional
  2228 transformations, notably reverse application and composition:
  2229 
  2230   x |> f                f #> g
  2231   (x, y) |-> f          f #-> g
  2232 
  2233 * Pure/library.ML: introduced/changed precedence of infix operators:
  2234 
  2235   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2236   infix 2 ?;
  2237   infix 3 o oo ooo oooo;
  2238   infix 4 ~~ upto downto;
  2239 
  2240 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2241 infix operators.
  2242 
  2243 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2244 fold_map support linear functional transformations and nesting.  For
  2245 example:
  2246 
  2247   fold f [x1, ..., xN] y =
  2248     y |> f x1 |> ... |> f xN
  2249 
  2250   (fold o fold) f [xs1, ..., xsN] y =
  2251     y |> fold f xs1 |> ... |> fold f xsN
  2252 
  2253   fold f [x1, ..., xN] =
  2254     f x1 #> ... #> f xN
  2255 
  2256   (fold o fold) f [xs1, ..., xsN] =
  2257     fold f xs1 #> ... #> fold f xsN
  2258 
  2259 * Pure/library.ML: the following selectors on type 'a option are
  2260 available:
  2261 
  2262   the:               'a option -> 'a  (*partial*)
  2263   these:             'a option -> 'a  where 'a = 'b list
  2264   the_default: 'a -> 'a option -> 'a
  2265   the_list:          'a option -> 'a list
  2266 
  2267 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2268 basic operations for association lists, following natural argument
  2269 order; moreover the explicit equality predicate passed here avoids
  2270 potentially expensive polymorphic runtime equality checks.
  2271 The old functions may be expressed as follows:
  2272 
  2273   assoc = uncurry (AList.lookup (op =))
  2274   assocs = these oo AList.lookup (op =)
  2275   overwrite = uncurry (AList.update (op =)) o swap
  2276 
  2277 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2278 
  2279   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2280   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2281 
  2282 replacing make_keylist and keyfilter (occassionally used)
  2283 Naive rewrites:
  2284 
  2285   make_keylist = AList.make
  2286   keyfilter = AList.find (op =)
  2287 
  2288 * eq_fst and eq_snd now take explicit equality parameter, thus
  2289   avoiding eqtypes. Naive rewrites:
  2290 
  2291     eq_fst = eq_fst (op =)
  2292     eq_snd = eq_snd (op =)
  2293 
  2294 * Removed deprecated apl and apr (rarely used).
  2295   Naive rewrites:
  2296 
  2297     apl (n, op) =>>= curry op n
  2298     apr (op, m) =>>= fn n => op (n, m)
  2299 
  2300 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2301 provides a reasonably efficient light-weight implementation of sets as
  2302 lists.
  2303 
  2304 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2305 few new operations; existing lookup and update are now curried to
  2306 follow natural argument order (for use with fold etc.);
  2307 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2308 
  2309 * Pure/General: output via the Isabelle channels of
  2310 writeln/warning/error etc. is now passed through Output.output, with a
  2311 hook for arbitrary transformations depending on the print_mode
  2312 (cf. Output.add_mode -- the first active mode that provides a output
  2313 function wins).  Already formatted output may be embedded into further
  2314 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2315 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2316 accommodate easy composition of diagnostic messages etc.  Programmers
  2317 rarely need to care about Output.output or Output.raw at all, with
  2318 some notable exceptions: Output.output is required when bypassing the
  2319 standard channels (writeln etc.), or in token translations to produce
  2320 properly formatted results; Output.raw is required when capturing
  2321 already output material that will eventually be presented to the user
  2322 a second time.  For the default print mode, both Output.output and
  2323 Output.raw have no effect.
  2324 
  2325 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2326 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2327 cumulative results are displayed at the end of a batch session.
  2328 
  2329 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2330 replaced by File.platform_path and File.shell_path (with appropriate
  2331 hooks).  This provides a clean interface for unusual systems where the
  2332 internal and external process view of file names are different.
  2333 
  2334 * Pure: more efficient orders for basic syntactic entities: added
  2335 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2336 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2337 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2338 orders now -- potential INCOMPATIBILITY for code that depends on a
  2339 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2340 Library.sort_strings on result).
  2341 
  2342 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2343 fold_types traverse types/terms from left to right, observing natural
  2344 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2345 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2346 
  2347 * Pure: name spaces have been refined, with significant changes of the
  2348 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2349 to extern(_table).  The plain name entry path is superceded by a
  2350 general 'naming' context, which also includes the 'policy' to produce
  2351 a fully qualified name and external accesses of a fully qualified
  2352 name; NameSpace.extend is superceded by context dependent
  2353 Sign.declare_name.  Several theory and proof context operations modify
  2354 the naming context.  Especially note Theory.restore_naming and
  2355 ProofContext.restore_naming to get back to a sane state; note that
  2356 Theory.add_path is no longer sufficient to recover from
  2357 Theory.absolute_path in particular.
  2358 
  2359 * Pure: new flags short_names (default false) and unique_names
  2360 (default true) for controlling output of qualified names.  If
  2361 short_names is set, names are printed unqualified.  If unique_names is
  2362 reset, the name prefix is reduced to the minimum required to achieve
  2363 the original result when interning again, even if there is an overlap
  2364 with earlier declarations.
  2365 
  2366 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2367 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2368 (useful for printing error messages).  INCOMPATIBILITY.
  2369 
  2370 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2371 Theory.theory are now identified, referring to the universal
  2372 Context.theory (see Pure/context.ML).  Actual signature and theory
  2373 content is managed as theory data.  The old code and interfaces were
  2374 spread over many files and structures; the new arrangement introduces
  2375 considerable INCOMPATIBILITY to gain more clarity:
  2376 
  2377   Context -- theory management operations (name, identity, inclusion,
  2378     parents, ancestors, merge, etc.), plus generic theory data;
  2379 
  2380   Sign -- logical signature and syntax operations (declaring consts,
  2381     types, etc.), plus certify/read for common entities;
  2382 
  2383   Theory -- logical theory operations (stating axioms, definitions,
  2384     oracles), plus a copy of logical signature operations (consts,
  2385     types, etc.); also a few basic management operations (Theory.copy,
  2386     Theory.merge, etc.)
  2387 
  2388 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2389 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2390 for convenience -- they merely return the theory.
  2391 
  2392 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2393 
  2394 * Pure: the Isar proof context type is already defined early in Pure
  2395 as Context.proof (note that ProofContext.context and Proof.context are
  2396 aliases, where the latter is the preferred name).  This enables other
  2397 Isabelle components to refer to that type even before Isar is present.
  2398 
  2399 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2400 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2401 any of these kinds.  For example, Sign.intern typeK is now
  2402 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2403 Theory.hide_types.  Also note that former
  2404 Theory.hide_classes/types/consts are now
  2405 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2406 internalize their arguments!  INCOMPATIBILITY.
  2407 
  2408 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2409 datatype thmref (with constructors Name and NameSelection) instead of
  2410 plain string -- INCOMPATIBILITY;
  2411 
  2412 * Pure: cases produced by proof methods specify options, where NONE
  2413 means to remove case bindings -- INCOMPATIBILITY in
  2414 (RAW_)METHOD_CASES.
  2415 
  2416 * Pure: the following operations retrieve axioms or theorems from a
  2417 theory node or theory hierarchy, respectively:
  2418 
  2419   Theory.axioms_of: theory -> (string * term) list
  2420   Theory.all_axioms_of: theory -> (string * term) list
  2421   PureThy.thms_of: theory -> (string * thm) list
  2422   PureThy.all_thms_of: theory -> (string * thm) list
  2423 
  2424 * Pure: print_tac now outputs the goal through the trace channel.
  2425 
  2426 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2427 Reference Toplevel.debug (default false) controls detailed printing
  2428 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2429 controls execution profiling -- set to 1 for time and 2 for space
  2430 (both increase the runtime).
  2431 
  2432 * Isar session: The initial use of ROOT.ML is now always timed,
  2433 i.e. the log will show the actual process times, in contrast to the
  2434 elapsed wall-clock time that the outer shell wrapper produces.
  2435 
  2436 * Simplifier: improved handling of bound variables (nameless
  2437 representation, avoid allocating new strings).  Simprocs that invoke
  2438 the Simplifier recursively should use Simplifier.inherit_bounds to
  2439 avoid local name clashes.  Failure to do so produces warnings
  2440 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2441 for further details.
  2442 
  2443 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2444 bindings for all theorems stored within a given theory; this may help
  2445 in porting non-Isar theories to Isar ones, while keeping ML proof
  2446 scripts for the time being.
  2447 
  2448 * ML operator HTML.with_charset specifies the charset begin used for
  2449 generated HTML files.  For example:
  2450 
  2451   HTML.with_charset "utf-8" use_thy "Hebrew";
  2452   HTML.with_charset "utf-8" use_thy "Chinese";
  2453 
  2454 
  2455 *** System ***
  2456 
  2457 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2458 isabelle, isatool etc.).
  2459 
  2460 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2461 isatool doc, isatool mkdir, display_drafts etc.).
  2462 
  2463 * isatool usedir: option -f allows specification of the ML file to be
  2464 used by Isabelle; default is ROOT.ML.
  2465 
  2466 * New isatool version outputs the version identifier of the Isabelle
  2467 distribution being used.
  2468 
  2469 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2470 (containing Boolean satisfiability problems) into Isabelle/HOL
  2471 theories.
  2472 
  2473 
  2474 
  2475 New in Isabelle2004 (April 2004)
  2476 --------------------------------
  2477 
  2478 *** General ***
  2479 
  2480 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2481   Replaces linorder.ML.
  2482 
  2483 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2484   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2485   (\<a>...\<z>), are now considered normal letters, and can therefore
  2486   be used anywhere where an ASCII letter (a...zA...Z) has until
  2487   now. COMPATIBILITY: This obviously changes the parsing of some
  2488   terms, especially where a symbol has been used as a binder, say
  2489   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2490   as an identifier.  Fix it by inserting a space around former
  2491   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2492   existing theory and ML files.
  2493 
  2494 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2495 
  2496 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2497   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2498   a normal (but invisible) letter. For multiple letter subscripts repeat
  2499   \<^isub> like this: x\<^isub>1\<^isub>2.
  2500 
  2501 * Pure: There are now sub-/superscripts that can span more than one
  2502   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2503   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2504   superscript. The new control characters are not identifier parts.
  2505 
  2506 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2507   content of "..." to the latex file instead of \isacntrl... . The "..."
  2508   may consist of any printable characters excluding the end bracket >.
  2509 
  2510 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2511   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2512   declare constants "final", which prevents their being given a definition
  2513   later.  It is useful for constants whose behaviour is fixed axiomatically
  2514   rather than definitionally, such as the meta-logic connectives.
  2515 
  2516 * Pure: 'instance' now handles general arities with general sorts
  2517   (i.e. intersections of classes),
  2518 
  2519 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2520   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2521   It can be changed to alter the colors/layout of generated pages.
  2522 
  2523 
  2524 *** Isar ***
  2525 
  2526 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2527   cut_tac, subgoal_tac and thin_tac:
  2528   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2529     locales are no longer forced to write Isar proof scripts.
  2530     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2531     emulations.
  2532   - INCOMPATIBILITY: names of variables to be instantiated may no
  2533     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2534     This is consistent with the instantiation attribute "where".
  2535 
  2536 * Attributes "where" and "of":
  2537   - Now take type variables of instantiated theorem into account when reading
  2538     the instantiation string.  This fixes a bug that caused instantiated
  2539     theorems to have too special types in some circumstances.
  2540   - "where" permits explicit instantiations of type variables.
  2541 
  2542 * Calculation commands "moreover" and "also" no longer interfere with
  2543   current facts ("this"), admitting arbitrary combinations with "then"
  2544   and derived forms.
  2545 
  2546 * Locales:
  2547   - Goal statements involving the context element "includes" no longer
  2548     generate theorems with internal delta predicates (those ending on
  2549     "_axioms") in the premise.
  2550     Resolve particular premise with <locale>.intro to obtain old form.
  2551   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2552     specification and "includes" elements in goal statement.
  2553   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2554     [intro?] and [elim?] (respectively) by default.
  2555   - Experimental command for instantiation of locales in proof contexts:
  2556         instantiate <label>[<attrs>]: <loc>
  2557     Instantiates locale <loc> and adds all its theorems to the current context
  2558     taking into account their attributes.  Label and attrs are optional
  2559     modifiers, like in theorem declarations.  If present, names of
  2560     instantiated theorems are qualified with <label>, and the attributes
  2561     <attrs> are applied after any attributes these theorems might have already.
  2562       If the locale has assumptions, a chained fact of the form
  2563     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2564     are derived.  The command does not support old-style locales declared
  2565     with "locale (open)".
  2566       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2567 
  2568 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2569   (Isar) contexts.
  2570 
  2571 
  2572 *** HOL ***
  2573 
  2574 * Proof import: new image HOL4 contains the imported library from
  2575   the HOL4 system with about 2500 theorems. It is imported by
  2576   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2577   can be used like any other Isabelle image.  See
  2578   HOL/Import/HOL/README for more information.
  2579 
  2580 * Simplifier:
  2581   - Much improved handling of linear and partial orders.
  2582     Reasoners for linear and partial orders are set up for type classes
  2583     "linorder" and "order" respectively, and are added to the default simpset
  2584     as solvers.  This means that the simplifier can build transitivity chains
  2585     to solve goals from the assumptions.
  2586   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2587     of blast or auto after simplification become unnecessary because the goal
  2588     is solved by simplification already.
  2589 
  2590 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2591     all proved in axiomatic type classes for semirings, rings and fields.
  2592 
  2593 * Numerics:
  2594   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2595     now formalized using the Ring_and_Field theory mentioned above.
  2596   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2597     than before, because now they are set up once in a generic manner.
  2598   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2599     Look for the general versions in Ring_and_Field (and Power if they concern
  2600     exponentiation).
  2601 
  2602 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2603 
  2604 * Records:
  2605   - Record types are now by default printed with their type abbreviation
  2606     instead of the list of all field types. This can be configured via
  2607     the reference "print_record_type_abbr".
  2608   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2609     (not enabled by default).
  2610   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2611     EX x. x = sel r to True (not enabled by default).
  2612   - Tactic "record_split_simp_tac" to split and simplify records added.
  2613 
  2614 * 'specification' command added, allowing for definition by
  2615   specification.  There is also an 'ax_specification' command that
  2616   introduces the new constants axiomatically.
  2617 
  2618 * arith(_tac) is now able to generate counterexamples for reals as well.
  2619 
  2620 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2621 
  2622 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2623   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2624 
  2625 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2626   matrix theory to linear programming.
  2627 
  2628 * Unions and Intersections:
  2629   The latex output syntax of UN and INT has been changed
  2630   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2631   i.e. the index formulae has become a subscript.
  2632   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2633 
  2634 * Unions and Intersections over Intervals:
  2635   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2636   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2637   like in normal math, and corresponding versions for < and for intersection.
  2638 
  2639 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2640   lexicographic dictonary ordering has been added as "lexord".
  2641 
  2642 * ML: the legacy theory structures Int and List have been removed. They had
  2643   conflicted with ML Basis Library structures having the same names.
  2644 
  2645 * 'refute' command added to search for (finite) countermodels.  Only works
  2646   for a fragment of HOL.  The installation of an external SAT solver is
  2647   highly recommended.  See "HOL/Refute.thy" for details.
  2648 
  2649 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2650   formulae under an assignment of free variables to random values.
  2651   In contrast to 'refute', it can deal with inductive datatypes,
  2652   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2653   for examples.
  2654 
  2655 
  2656 *** HOLCF ***
  2657 
  2658 * Streams now come with concatenation and are part of the HOLCF image
  2659 
  2660 
  2661 
  2662 New in Isabelle2003 (May 2003)
  2663 ------------------------------
  2664 
  2665 *** General ***
  2666 
  2667 * Provers/simplifier:
  2668 
  2669   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2670     Assumptions are now subject to complete mutual simplification,
  2671     not just from left to right. The simplifier now preserves
  2672     the order of assumptions.
  2673 
  2674     Potential INCOMPATIBILITY:
  2675 
  2676     -- simp sometimes diverges where the old version did
  2677        not, e.g. invoking simp on the goal
  2678 
  2679         [| P (f x); y = x; f x = f y |] ==> Q
  2680 
  2681        now gives rise to the infinite reduction sequence
  2682 
  2683         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2684 
  2685        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2686        kind of problem.
  2687 
  2688     -- Tactics combining classical reasoner and simplification (such as auto)
  2689        are also affected by this change, because many of them rely on
  2690        simp. They may sometimes diverge as well or yield a different numbers
  2691        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2692        in case of problems. Sometimes subsequent calls to the classical
  2693        reasoner will fail because a preceeding call to the simplifier too
  2694        eagerly simplified the goal, e.g. deleted redundant premises.
  2695 
  2696   - The simplifier trace now shows the names of the applied rewrite rules
  2697 
  2698   - You can limit the number of recursive invocations of the simplifier
  2699     during conditional rewriting (where the simplifie tries to solve the
  2700     conditions before applying the rewrite rule):
  2701     ML "simp_depth_limit := n"
  2702     where n is an integer. Thus you can force termination where previously
  2703     the simplifier would diverge.
  2704 
  2705   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2706 
  2707   - No longer aborts on failed congruence proof.  Instead, the
  2708     congruence is ignored.
  2709 
  2710 * Pure: New generic framework for extracting programs from constructive
  2711   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2712   as HOL/Extraction for some case studies.
  2713 
  2714 * Pure: The main goal of the proof state is no longer shown by default, only
  2715 the subgoals. This behaviour is controlled by a new flag.
  2716    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2717 (ML: Proof.show_main_goal).
  2718 
  2719 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2720 rules whose conclusion matches subgoal 1:
  2721       PG menu: Isabelle/Isar -> Show me -> matching rules
  2722 The rules are ordered by how closely they match the subgoal.
  2723 In particular, rules that solve a subgoal outright are displayed first
  2724 (or rather last, the way they are printed).
  2725 (ML: ProofGeneral.print_intros())
  2726 
  2727 * Pure: New flag trace_unify_fail causes unification to print
  2728 diagnostic information (PG: in trace buffer) when it fails. This is
  2729 useful for figuring out why single step proofs like rule, erule or
  2730 assumption failed.
  2731 
  2732 * Pure: Locale specifications now produce predicate definitions
  2733 according to the body of text (covering assumptions modulo local
  2734 definitions); predicate "loc_axioms" covers newly introduced text,
  2735 while "loc" is cumulative wrt. all included locale expressions; the
  2736 latter view is presented only on export into the global theory
  2737 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2738 on the old view without predicates;
  2739 
  2740 * Pure: predefined locales "var" and "struct" are useful for sharing
  2741 parameters (as in CASL, for example); just specify something like
  2742 ``var x + var y + struct M'' as import;
  2743 
  2744 * Pure: improved thms_containing: proper indexing of facts instead of
  2745 raw theorems; check validity of results wrt. current name space;
  2746 include local facts of proof configuration (also covers active
  2747 locales), cover fixed variables in index; may use "_" in term
  2748 specification; an optional limit for the number of printed facts may
  2749 be given (the default is 40);
  2750 
  2751 * Pure: disallow duplicate fact bindings within new-style theory files
  2752 (batch-mode only);
  2753 
  2754 * Provers: improved induct method: assumptions introduced by case
  2755 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2756 the goal statement); "foo" still refers to all facts collectively;
  2757 
  2758 * Provers: the function blast.overloaded has been removed: all constants
  2759 are regarded as potentially overloaded, which improves robustness in exchange
  2760 for slight decrease in efficiency;
  2761 
  2762 * Provers/linorder: New generic prover for transitivity reasoning over
  2763 linear orders.  Note: this prover is not efficient!
  2764 
  2765 * Isar: preview of problems to finish 'show' now produce an error
  2766 rather than just a warning (in interactive mode);
  2767 
  2768 
  2769 *** HOL ***
  2770 
  2771 * arith(_tac)
  2772 
  2773  - Produces a counter example if it cannot prove a goal.
  2774    Note that the counter example may be spurious if the goal is not a formula
  2775    of quantifier-free linear arithmetic.
  2776    In ProofGeneral the counter example appears in the trace buffer.
  2777 
  2778  - Knows about div k and mod k where k is a numeral of type nat or int.
  2779 
  2780  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2781    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2782    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2783 
  2784 * simp's arithmetic capabilities have been enhanced a bit: it now
  2785 takes ~= in premises into account (by performing a case split);
  2786 
  2787 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2788 are distributed over a sum of terms;
  2789 
  2790 * New tactic "trans_tac" and method "trans" instantiate
  2791 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2792 "<=", "<" and "=").
  2793 
  2794 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2795 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2796 
  2797 * 'typedef' command has new option "open" to suppress the set
  2798 definition;
  2799 
  2800 * functions Min and Max on finite sets have been introduced (theory
  2801 Finite_Set);
  2802 
  2803 * attribute [symmetric] now works for relations as well; it turns
  2804 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2805 
  2806 * induct over a !!-quantified statement (say !!x1..xn):
  2807   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2808 
  2809 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2810 %x. None. Warning: empty_def now refers to the previously hidden definition
  2811 of the empty set.
  2812 
  2813 * Algebra: formalization of classical algebra.  Intended as base for
  2814 any algebraic development in Isabelle.  Currently covers group theory
  2815 (up to Sylow's theorem) and ring theory (Universal Property of
  2816 Univariate Polynomials).  Contributions welcome;
  2817 
  2818 * GroupTheory: deleted, since its material has been moved to Algebra;
  2819 
  2820 * Complex: new directory of the complex numbers with numeric constants,
  2821 nonstandard complex numbers, and some complex analysis, standard and
  2822 nonstandard (Jacques Fleuriot);
  2823 
  2824 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2825 
  2826 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2827 Fleuriot);
  2828 
  2829 * Real/HahnBanach: updated and adapted to locales;
  2830 
  2831 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2832 Gray and Kramer);
  2833 
  2834 * UNITY: added the Meier-Sanders theory of progress sets;
  2835 
  2836 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2837 as abstract algorithms, instantiated to the JVM;
  2838 
  2839 * Bali: Java source language formalization. Type system, operational
  2840 semantics, axiomatic semantics. Supported language features:
  2841 classes, interfaces, objects,virtual methods, static methods,
  2842 static/instance fields, arrays, access modifiers, definite
  2843 assignment, exceptions.
  2844 
  2845 
  2846 *** ZF ***
  2847 
  2848 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2849 universe, etc.);
  2850 
  2851 * Main ZF: virtually all theories converted to new-style format;
  2852 
  2853 
  2854 *** ML ***
  2855 
  2856 * Pure: Tactic.prove provides sane interface for internal proofs;
  2857 omits the infamous "standard" operation, so this is more appropriate
  2858 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2859 
  2860 * Pure: improved error reporting of simprocs;
  2861 
  2862 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2863 up simprocs;
  2864 
  2865 
  2866 *** Document preparation ***
  2867 
  2868 * uses \par instead of \\ for line breaks in theory text. This may
  2869 shift some page breaks in large documents. To get the old behaviour
  2870 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2871 
  2872 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2873 other packages
  2874 
  2875 * \<euro> now needs package babel/greek instead of marvosym (which
  2876 broke \Rightarrow)
  2877 
  2878 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2879 textcomp package)
  2880 
  2881 
  2882 
  2883 New in Isabelle2002 (March 2002)
  2884 --------------------------------
  2885 
  2886 *** Document preparation ***
  2887 
  2888 * greatly simplified document preparation setup, including more
  2889 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2890 instructive isatool mkdir; users should basically be able to get
  2891 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2892 users may run a separate document processing stage manually like this:
  2893 "isatool usedir -D output HOL Test && isatool document Test/output";
  2894 
  2895 * theory dependency graph may now be incorporated into documents;
  2896 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2897 with \includegraphics of LaTeX;
  2898 
  2899 * proper spacing of consecutive markup elements, especially text
  2900 blocks after section headings;
  2901 
  2902 * support bold style (for single symbols only), input syntax is like
  2903 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2904 
  2905 * \<bullet> is now output as bold \cdot by default, which looks much
  2906 better in printed text;
  2907 
  2908 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2909 note that these symbols are currently unavailable in Proof General /
  2910 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2911 
  2912 * isatool latex no longer depends on changed TEXINPUTS, instead
  2913 isatool document copies the Isabelle style files to the target
  2914 location;
  2915 
  2916 
  2917 *** Isar ***
  2918 
  2919 * Pure/Provers: improved proof by cases and induction;
  2920   - 'case' command admits impromptu naming of parameters (such as
  2921     "case (Suc n)");
  2922   - 'induct' method divinates rule instantiation from the inductive
  2923     claim; no longer requires excessive ?P bindings for proper
  2924     instantiation of cases;
  2925   - 'induct' method properly enumerates all possibilities of set/type
  2926     rules; as a consequence facts may be also passed through *type*
  2927     rules without further ado;
  2928   - 'induct' method now derives symbolic cases from the *rulified*
  2929     rule (before it used to rulify cases stemming from the internal
  2930     atomized version); this means that the context of a non-atomic
  2931     statement becomes is included in the hypothesis, avoiding the
  2932     slightly cumbersome show "PROP ?case" form;
  2933   - 'induct' may now use elim-style induction rules without chaining
  2934     facts, using ``missing'' premises from the goal state; this allows
  2935     rules stemming from inductive sets to be applied in unstructured
  2936     scripts, while still benefitting from proper handling of non-atomic
  2937     statements; NB: major inductive premises need to be put first, all
  2938     the rest of the goal is passed through the induction;
  2939   - 'induct' proper support for mutual induction involving non-atomic
  2940     rule statements (uses the new concept of simultaneous goals, see
  2941     below);
  2942   - append all possible rule selections, but only use the first
  2943     success (no backtracking);
  2944   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2945   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2946   - added 'print_induct_rules' (covered by help item in recent Proof
  2947     General versions);
  2948   - moved induct/cases attributes to Pure, methods to Provers;
  2949   - generic method setup instantiated for FOL and HOL;
  2950 
  2951 * Pure: support multiple simultaneous goal statements, for example
  2952 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2953 meta-level mechanism, this acts as if several individual goals had
  2954 been stated separately; in particular common proof methods need to be
  2955 repeated in order to cover all claims; note that a single elimination
  2956 step is *not* sufficient to establish the two conjunctions, so this
  2957 fails:
  2958 
  2959   assume "A & B" then have A and B ..   (*".." fails*)
  2960 
  2961 better use "obtain" in situations as above; alternative refer to
  2962 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2963 
  2964 * Pure: proper integration with ``locales''; unlike the original
  2965 version by Florian Kammller, Isar locales package high-level proof
  2966 contexts rather than raw logical ones (e.g. we admit to include
  2967 attributes everywhere); operations on locales include merge and
  2968 rename; support for implicit arguments (``structures''); simultaneous
  2969 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2970 some examples;
  2971 
  2972 * Pure: the following commands have been ``localized'', supporting a
  2973 target locale specification "(in name)": 'lemma', 'theorem',
  2974 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2975 stored both within the locale and at the theory level (exported and
  2976 qualified by the locale name);
  2977 
  2978 * Pure: theory goals may now be specified in ``long'' form, with
  2979 ad-hoc contexts consisting of arbitrary locale elements. for example
  2980 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2981 definitions may be given, too); the result is a meta-level rule with
  2982 the context elements being discharged in the obvious way;
  2983 
  2984 * Pure: new proof command 'using' allows to augment currently used
  2985 facts after a goal statement ('using' is syntactically analogous to
  2986 'apply', but acts on the goal's facts only); this allows chained facts
  2987 to be separated into parts given before and after a claim, as in
  2988 ``from a and b have C using d and e <proof>'';
  2989 
  2990 * Pure: renamed "antecedent" case to "rule_context";
  2991 
  2992 * Pure: new 'judgment' command records explicit information about the
  2993 object-logic embedding (used by several tools internally); no longer
  2994 use hard-wired "Trueprop";
  2995 
  2996 * Pure: added 'corollary' command;
  2997 
  2998 * Pure: fixed 'token_translation' command;
  2999 
  3000 * Pure: removed obsolete 'exported' attribute;
  3001 
  3002 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3003 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3004 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3005 
  3006 * Pure: method 'atomize' presents local goal premises as object-level
  3007 statements (atomic meta-level propositions); setup controlled via
  3008 rewrite rules declarations of 'atomize' attribute; example
  3009 application: 'induct' method with proper rule statements in improper
  3010 proof *scripts*;
  3011 
  3012 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3013 now consider the syntactic context of assumptions, giving a better
  3014 chance to get type-inference of the arguments right (this is
  3015 especially important for locales);
  3016 
  3017 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3018 mode;
  3019 
  3020 * Pure/obtain: the formal conclusion "thesis", being marked as
  3021 ``internal'', may no longer be reference directly in the text;
  3022 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3023 situations;
  3024 
  3025 * Pure: generic 'sym' attribute which declares a rule both as pure
  3026 'elim?' and for the 'symmetric' operation;
  3027 
  3028 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3029 text; the fixed correlation with particular command syntax has been
  3030 discontinued;
  3031 
  3032 * Pure: new method 'rules' is particularly well-suited for proof
  3033 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3034 but often produces more compact proof terms with less detours;
  3035 
  3036 * Pure/Provers/classical: simplified integration with pure rule
  3037 attributes and methods; the classical "intro?/elim?/dest?"
  3038 declarations coincide with the pure ones; the "rule" method no longer
  3039 includes classically swapped intros; "intro" and "elim" methods no
  3040 longer pick rules from the context; also got rid of ML declarations
  3041 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3042 INCOMPATIBILITY;
  3043 
  3044 * Provers/classical: attribute 'swapped' produces classical inversions
  3045 of introduction rules;
  3046 
  3047 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3048 rules instead of full simplifier context; 'iff' attribute handles
  3049 conditional rules;
  3050 
  3051 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3052 
  3053 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3054 "(permissive)" option to recover old behavior;
  3055 
  3056 * HOL: 'inductive' no longer features separate (collective) attributes
  3057 for 'intros' (was found too confusing);
  3058 
  3059 * HOL: properly declared induction rules less_induct and
  3060 wf_induct_rule;
  3061 
  3062 
  3063 *** HOL ***
  3064 
  3065 * HOL: moved over to sane numeral syntax; the new policy is as
  3066 follows:
  3067 
  3068   - 0 and 1 are polymorphic constants, which are defined on any
  3069   numeric type (nat, int, real etc.);
  3070 
  3071   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3072   binary representation internally;
  3073 
  3074   - type nat has special constructor Suc, and generally prefers Suc 0
  3075   over 1::nat and Suc (Suc 0) over 2::nat;
  3076 
  3077 This change may cause significant problems of INCOMPATIBILITY; here
  3078 are some hints on converting existing sources:
  3079 
  3080   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3081   entities, so expressions involving "-" (unary or binary minus) need
  3082   to be spaced properly;
  3083 
  3084   - existing occurrences of "1" may need to be constraint "1::nat" or
  3085   even replaced by Suc 0; similar for old "2";
  3086 
  3087   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3088 
  3089   - remove all special provisions on numerals in proofs;
  3090 
  3091 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3092 representation (depends on bin_arith_simps in the default context);
  3093 
  3094 * HOL: symbolic syntax for x^2 (numeral 2);
  3095 
  3096 * HOL: the class of all HOL types is now called "type" rather than
  3097 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3098 in axclass/classes, instance/arities, and (usually rare) occurrences
  3099 in typings (of consts etc.); internally the class is called
  3100 "HOL.type", ML programs should refer to HOLogic.typeS;
  3101 
  3102 * HOL/record package improvements:
  3103   - new derived operations "fields" to build a partial record section,
  3104     "extend" to promote a fixed record to a record scheme, and
  3105     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3106     declared as simp by default;
  3107   - shared operations ("more", "fields", etc.) now need to be always
  3108     qualified) --- potential INCOMPATIBILITY;
  3109   - removed "make_scheme" operations (use "make" with "extend") --
  3110     INCOMPATIBILITY;
  3111   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3112   - provides cases/induct rules for use with corresponding Isar
  3113     methods (for concrete records, record schemes, concrete more
  3114     parts, and schematic more parts -- in that order);
  3115   - internal definitions directly based on a light-weight abstract
  3116     theory of product types over typedef rather than datatype;
  3117 
  3118 * HOL: generic code generator for generating executable ML code from
  3119 specifications; specific support for HOL constructs such as inductive
  3120 datatypes and sets, as well as recursive functions; can be invoked
  3121 via 'generate_code' theory section;
  3122 
  3123 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3124 
  3125 * HOL: consolidated and renamed several theories.  In particular:
  3126         Ord.thy has been absorbed into HOL.thy
  3127         String.thy has been absorbed into List.thy
  3128 
  3129 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3130 (beware of argument permutation!);
  3131 
  3132 * HOL: linorder_less_split superseded by linorder_cases;
  3133 
  3134 * HOL/List: "nodups" renamed to "distinct";
  3135 
  3136 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3137 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3138   - Ex_def has changed, now need to use some_eq_ex
  3139 
  3140 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3141 in this (rare) case use:
  3142 
  3143   delSWrapper "split_all_tac"
  3144   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3145 
  3146 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3147 MAY FAIL;
  3148 
  3149 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3150 Isabelle's type classes, ^ on functions and relations has too general
  3151 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3152 necessary to attach explicit type constraints;
  3153 
  3154 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3155 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3156 renamed accordingly (eg "compI" -> "rel_compI").
  3157 
  3158 * HOL: syntax translations now work properly with numerals and records
  3159 expressions;
  3160 
  3161 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3162 of "lam" -- INCOMPATIBILITY;
  3163 
  3164 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3165 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3166 renamed "Product_Type.unit";
  3167 
  3168 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3169 
  3170 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3171 the "cases" method);
  3172 
  3173 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3174 Florian Kammller);
  3175 
  3176 * HOL/IMP: updated and converted to new-style theory format; several
  3177 parts turned into readable document, with proper Isar proof texts and
  3178 some explanations (by Gerwin Klein);
  3179 
  3180 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3181 
  3182 * HOL-Hyperreal is now a logic image;
  3183 
  3184 
  3185 *** HOLCF ***
  3186 
  3187 * Isar: consts/constdefs supports mixfix syntax for continuous
  3188 operations;
  3189 
  3190 * Isar: domain package adapted to new-style theory format, e.g. see
  3191 HOLCF/ex/Dnat.thy;
  3192 
  3193 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3194 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3195 lift.induct_tac, always use UU instead of Undef;
  3196 
  3197 * HOLCF/IMP: updated and converted to new-style theory;
  3198 
  3199 
  3200 *** ZF ***
  3201 
  3202 * Isar: proper integration of logic-specific tools and packages,
  3203 including theory commands '(co)inductive', '(co)datatype',
  3204 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3205 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3206 
  3207 * theory Main no longer includes AC; for the Axiom of Choice, base
  3208 your theory on Main_ZFC;
  3209 
  3210 * the integer library now covers quotients and remainders, with many
  3211 laws relating division to addition, multiplication, etc.;
  3212 
  3213 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3214 typeless version of the formalism;
  3215 
  3216 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3217 format;
  3218 
  3219 * ZF/Induct: new directory for examples of inductive definitions,
  3220 including theory Multiset for multiset orderings; converted to
  3221 new-style theory format;
  3222 
  3223 * ZF: many new theorems about lists, ordinals, etc.;
  3224 
  3225 
  3226 *** General ***
  3227 
  3228 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3229 variable proof controls level of detail: 0 = no proofs (only oracle
  3230 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3231 also ref manual for further ML interfaces;
  3232 
  3233 * Pure/axclass: removed obsolete ML interface
  3234 goal_subclass/goal_arity;
  3235 
  3236 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3237 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3238 separate tokens, so expressions involving minus need to be spaced
  3239 properly;
  3240 
  3241 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3242 rather than "infixl" or "infixr";
  3243 
  3244 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3245 sort constraint specifications in type inference; e.g. "x::_::foo"
  3246 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3247 type variable);
  3248 
  3249 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3250 control output of nested => (types); the default behavior is
  3251 "type_brackets";
  3252 
  3253 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3254 tokens into AST constants;
  3255 
  3256 * Pure/syntax: prefer later declarations of translations and print
  3257 translation functions; potential INCOMPATIBILITY: need to reverse
  3258 multiple declarations for same syntax element constant;
  3259 
  3260 * Pure/show_hyps reset by default (in accordance to existing Isar
  3261 practice);
  3262 
  3263 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3264 addSafter;
  3265 
  3266 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3267 as well;
  3268 
  3269 * system: tested support for MacOS X; should be able to get Isabelle +
  3270 Proof General to work in a plain Terminal after installing Poly/ML
  3271 (e.g. from the Isabelle distribution area) and GNU bash alone
  3272 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3273 support requires further installations, e.g. from
  3274 http://fink.sourceforge.net/);
  3275 
  3276 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3277 
  3278 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3279 of 40 MB), cf. ML_OPTIONS;
  3280 
  3281 * system: Proof General keywords specification is now part of the
  3282 Isabelle distribution (see etc/isar-keywords.el);
  3283 
  3284 * system: support for persistent Proof General sessions (refrain from
  3285 outdating all loaded theories on startup); user may create writable
  3286 logic images like this: ``isabelle -q HOL Test'';
  3287 
  3288 * system: smart selection of Isabelle process versus Isabelle
  3289 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3290 run both "isabelle" and "Isabelle" even if file names are badly
  3291 damaged (executable inspects the case of the first letter of its own
  3292 name); added separate "isabelle-process" and "isabelle-interface";
  3293 
  3294 * system: refrain from any attempt at filtering input streams; no
  3295 longer support ``8bit'' encoding of old isabelle font, instead proper
  3296 iso-latin characters may now be used; the related isatools
  3297 "symbolinput" and "nonascii" have disappeared as well;
  3298 
  3299 * system: removed old "xterm" interface (the print modes "xterm" and
  3300 "xterm_color" are still available for direct use in a suitable
  3301 terminal);
  3302 
  3303 
  3304 
  3305 New in Isabelle99-2 (February 2001)
  3306 -----------------------------------
  3307 
  3308 *** Overview of INCOMPATIBILITIES ***
  3309 
  3310 * HOL: please note that theories in the Library and elsewhere often use the
  3311 new-style (Isar) format; to refer to their theorems in an ML script you must
  3312 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3313 
  3314 * HOL: inductive package no longer splits induction rule aggressively,
  3315 but only as far as specified by the introductions given; the old
  3316 format may be recovered via ML function complete_split_rule or attribute
  3317 'split_rule (complete)';
  3318 
  3319 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3320 gfp_Tarski to gfp_unfold;
  3321 
  3322 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3323 
  3324 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3325 relation); infix "^^" has been renamed "``"; infix "``" has been
  3326 renamed "`"; "univalent" has been renamed "single_valued";
  3327 
  3328 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3329 operation;
  3330 
  3331 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3332 
  3333 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3334 
  3335 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3336 consequence, it is no longer monotonic wrt. the local goal context
  3337 (which is now passed through the inductive cases);
  3338 
  3339 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3340 \<gg> to \<ggreater>;
  3341 
  3342 
  3343 *** Document preparation ***
  3344 
  3345 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3346 available: are "it" for near math-mode best-style output, "sl" for
  3347 slanted text style, and "tt" for plain type-writer; if no
  3348 \isabellestyle command is given, output is according to slanted
  3349 type-writer);
  3350 
  3351 * support sub/super scripts (for single symbols only), input syntax is
  3352 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3353 
  3354 * some more standard symbols; see Appendix A of the system manual for
  3355 the complete list of symbols defined in isabellesym.sty;
  3356 
  3357 * improved isabelle style files; more abstract symbol implementation
  3358 (should now use \isamath{...} and \isatext{...} in custom symbol
  3359 definitions);
  3360 
  3361 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3362 state; Note that presentation of goal states does not conform to
  3363 actual human-readable proof documents.  Please do not include goal
  3364 states into document output unless you really know what you are doing!
  3365 
  3366 * proper indentation of antiquoted output with proportional LaTeX
  3367 fonts;
  3368 
  3369 * no_document ML operator temporarily disables LaTeX document
  3370 generation;
  3371 
  3372 * isatool unsymbolize tunes sources for plain ASCII communication;
  3373 
  3374 
  3375 *** Isar ***
  3376 
  3377 * Pure: Isar now suffers initial goal statements to contain unbound
  3378 schematic variables (this does not conform to actual readable proof
  3379 documents, due to unpredictable outcome and non-compositional proof
  3380 checking); users who know what they are doing may use schematic goals
  3381 for Prolog-style synthesis of proven results;
  3382 
  3383 * Pure: assumption method (an implicit finishing) now handles actual
  3384 rules as well;
  3385 
  3386 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3387 initial goal, declare "that" only as Pure intro (only for single
  3388 steps); the "that" rule assumption may now be involved in implicit
  3389 finishing, thus ".." becomes a feasible for trivial obtains;
  3390 
  3391 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3392 instance proofs may be performed by "..";
  3393 
  3394 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3395 statements as well;
  3396 
  3397 * Pure: more robust selection of calculational rules;
  3398 
  3399 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3400 rule (as well as the assumption rule);
  3401 
  3402 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3403 lemmas, using the graph browser tool;
  3404 
  3405 * Pure: predict failure of "show" in interactive mode;
  3406 
  3407 * Pure: 'thms_containing' now takes actual terms as arguments;
  3408 
  3409 * HOL: improved method 'induct' --- now handles non-atomic goals
  3410 (potential INCOMPATIBILITY); tuned error handling;
  3411 
  3412 * HOL: cases and induct rules now provide explicit hints about the
  3413 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3414 any remaining facts are inserted into the goal verbatim;
  3415 
  3416 * HOL: local contexts (aka cases) may now contain term bindings as
  3417 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3418 the result to be shown in each case;
  3419 
  3420 * HOL: added 'recdef_tc' command;
  3421 
  3422 * isatool convert assists in eliminating legacy ML scripts;
  3423 
  3424 
  3425 *** HOL ***
  3426 
  3427 * HOL/Library: a collection of generic theories to be used together
  3428 with main HOL; the theory loader path already includes this directory
  3429 by default; the following existing theories have been moved here:
  3430 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3431 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3432 
  3433 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3434 modelling and verification task performed in Isabelle/HOL +
  3435 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3436 
  3437 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3438 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3439 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3440 'domain', this makes the theory consistent with mathematical
  3441 literature;
  3442 
  3443 * HOL basics: added overloaded operations "inverse" and "divide"
  3444 (infix "/"), syntax for generic "abs" operation, generic summation
  3445 operator \<Sum>;
  3446 
  3447 * HOL/typedef: simplified package, provide more useful rules (see also
  3448 HOL/subset.thy);
  3449 
  3450 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3451 now expressed as a proper nested rule (old-style tactic scripts may
  3452 require atomize_strip_tac to cope with non-atomic premises);
  3453 
  3454 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3455 to "split_conv" (old name still available for compatibility);
  3456 
  3457 * HOL: improved concrete syntax for strings (e.g. allows translation
  3458 rules with string literals);
  3459 
  3460 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3461  and Fleuriot's mechanization of analysis, including the transcendental
  3462  functions for the reals;
  3463 
  3464 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3465 
  3466 
  3467 *** CTT ***
  3468 
  3469 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3470 "lam" is displayed as TWO lambda-symbols
  3471 
  3472 * CTT: theory Main now available, containing everything (that is, Bool
  3473 and Arith);
  3474 
  3475 
  3476 *** General ***
  3477 
  3478 * Pure: the Simplifier has been implemented properly as a derived rule
  3479 outside of the actual kernel (at last!); the overall performance
  3480 penalty in practical applications is about 50%, while reliability of
  3481 the Isabelle inference kernel has been greatly improved;
  3482 
  3483 * print modes "brackets" and "no_brackets" control output of nested =>
  3484 (types) and ==> (props); the default behaviour is "brackets";
  3485 
  3486 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3487 as assumptions as well;
  3488 
  3489 * system: support Poly/ML 4.0;
  3490 
  3491 * system: isatool install handles KDE version 1 or 2;
  3492 
  3493 
  3494 
  3495 New in Isabelle99-1 (October 2000)
  3496 ----------------------------------
  3497 
  3498 *** Overview of INCOMPATIBILITIES ***
  3499 
  3500 * HOL: simplification of natural numbers is much changed; to partly
  3501 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3502 issue the following ML commands:
  3503 
  3504   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3505   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3506 
  3507 * HOL: simplification no longer dives into case-expressions; this is
  3508 controlled by "t.weak_case_cong" for each datatype t;
  3509 
  3510 * HOL: nat_less_induct renamed to less_induct;
  3511 
  3512 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3513 fixsome to patch .thy and .ML sources automatically;
  3514 
  3515   select_equality  -> some_equality
  3516   select_eq_Ex     -> some_eq_ex
  3517   selectI2EX       -> someI2_ex
  3518   selectI2         -> someI2
  3519   selectI          -> someI
  3520   select1_equality -> some1_equality
  3521   Eps_sym_eq       -> some_sym_eq_trivial
  3522   Eps_eq           -> some_eq_trivial
  3523 
  3524 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3525 
  3526 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3527 instead);
  3528 
  3529 * HOL: the recursion equations generated by 'recdef' are now called
  3530 f.simps instead of f.rules;
  3531 
  3532 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3533 
  3534 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3535 sometimes be needed;
  3536 
  3537 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3538 
  3539 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3540 
  3541 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3542 product is now "<*>" instead of "Times"; the lexicographic product is
  3543 now "<*lex*>" instead of "**";
  3544 
  3545 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3546 of main HOL, but was unused); better use HOL's datatype package;
  3547 
  3548 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3549 the old syntax may be recovered as follows:
  3550 
  3551   syntax (symbols)
  3552     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3553       (infixl "\\<oplus>" 100)
  3554 
  3555 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3556 
  3557 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3558 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3559 internally;
  3560 
  3561 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3562 changed from A/r to A//r;
  3563 
  3564 * ZF: new treatment of arithmetic (nat & int) may break some old
  3565 proofs;
  3566 
  3567 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3568 rulify -> rule_format, elimify -> elim_format, ...);
  3569 
  3570 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3571 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3572 should have to change intro!! to intro? only); replaced "delrule" by
  3573 "rule del";
  3574 
  3575 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3576 
  3577 * Provers: strengthened force_tac by using new first_best_tac;
  3578 
  3579 * LaTeX document preparation: several changes of isabelle.sty (see
  3580 lib/texinputs);
  3581 
  3582 
  3583 *** Document preparation ***
  3584 
  3585 * formal comments (text blocks etc.) in new-style theories may now
  3586 contain antiquotations of thm/prop/term/typ/text to be presented
  3587 according to latex print mode; concrete syntax is like this:
  3588 @{term[show_types] "f(x) = a + x"};
  3589 
  3590 * isatool mkdir provides easy setup of Isabelle session directories,
  3591 including proper document sources;
  3592 
  3593 * generated LaTeX sources are now deleted after successful run
  3594 (isatool document -c); may retain a copy somewhere else via -D option
  3595 of isatool usedir;
  3596 
  3597 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3598 style files, achieving self-contained LaTeX sources and simplifying
  3599 LaTeX debugging;
  3600 
  3601 * old-style theories now produce (crude) LaTeX output as well;
  3602 
  3603 * browser info session directories are now self-contained (may be put
  3604 on WWW server seperately); improved graphs of nested sessions; removed
  3605 graph for 'all sessions';
  3606 
  3607 * several improvements in isabelle style files; \isabellestyle{it}
  3608 produces fake math mode output; \isamarkupheader is now \section by
  3609 default; see lib/texinputs/isabelle.sty etc.;
  3610 
  3611 
  3612 *** Isar ***
  3613 
  3614 * Isar/Pure: local results and corresponding term bindings are now
  3615 subject to Hindley-Milner polymorphism (similar to ML); this
  3616 accommodates incremental type-inference very nicely;
  3617 
  3618 * Isar/Pure: new derived language element 'obtain' supports
  3619 generalized existence reasoning;
  3620 
  3621 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3622 support accumulation of results, without applying any rules yet;
  3623 useful to collect intermediate results without explicit name
  3624 references, and for use with transitivity rules with more than 2
  3625 premises;
  3626 
  3627 * Isar/Pure: scalable support for case-analysis type proofs: new
  3628 'case' language element refers to local contexts symbolically, as
  3629 produced by certain proof methods; internally, case names are attached
  3630 to theorems as "tags";
  3631 
  3632 * Isar/Pure: theory command 'hide' removes declarations from
  3633 class/type/const name spaces;
  3634 
  3635 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3636 indicate potential overloading;
  3637 
  3638 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3639 
  3640 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3641 "{a,b,c}" instead of {a,b,c};
  3642 
  3643 * Isar/Pure now provides its own version of intro/elim/dest
  3644 attributes; useful for building new logics, but beware of confusion
  3645 with the version in Provers/classical;
  3646 
  3647 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3648 case name 'antecedent';
  3649 
  3650 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3651 to the current context is now done automatically);
  3652 
  3653 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3654 for definining proof methods in ML;
  3655 
  3656 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3657 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3658 most cases, one should have to change intro!! to intro? only);
  3659 replaced "delrule" by "rule del";
  3660 
  3661 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3662 'symmetric' attribute (the latter supercedes [RS sym]);
  3663 
  3664 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3665 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3666 well (including splits);
  3667 
  3668 * Isar/Provers: Simplifier and Classical methods now support all kind
  3669 of modifiers used in the past, including 'cong', 'iff', etc.
  3670 
  3671 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3672 of Simplifier and Classical reasoner);
  3673 
  3674 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3675 now support named cases; major packages (inductive, datatype, primrec,
  3676 recdef) support case names and properly name parameters;
  3677 
  3678 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3679 monotonicity conditions are extracted to be proven at end of
  3680 calculations;
  3681 
  3682 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3683 method anyway;
  3684 
  3685 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3686 split_if split_if_asm; datatype package provides theorems foo.splits =
  3687 foo.split foo.split_asm for each datatype;
  3688 
  3689 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3690 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3691 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3692 use "(cases (simplified))" method in proper proof texts);
  3693 
  3694 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3695 
  3696 * Isar: names of theorems etc. may be natural numbers as well;
  3697 
  3698 * Isar: 'pr' command: optional arguments for goals_limit and
  3699 ProofContext.prems_limit; no longer prints theory contexts, but only
  3700 proof states;
  3701 
  3702 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3703 additional print modes to be specified; e.g. "pr(latex)" will print
  3704 proof state according to the Isabelle LaTeX style;
  3705 
  3706 * Isar: improved support for emulating tactic scripts, including proof
  3707 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3708 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3709 (for HOL datatypes);
  3710 
  3711 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3712 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3713 'proof method scripts' have to be in depth-first order;
  3714 
  3715 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3716 
  3717 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3718 should instead use individual commands for printing items
  3719 (print_commands, print_methods etc.);
  3720 
  3721 * Isar: added 'nothing' --- the empty list of theorems;
  3722 
  3723 
  3724 *** HOL ***
  3725 
  3726 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3727 corresponding virtual machine and a specification of its bytecode
  3728 verifier and a lightweight bytecode verifier, including proofs of
  3729 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3730 Cornelia Pusch (see also the homepage of project Bali at
  3731 http://isabelle.in.tum.de/Bali/);
  3732 
  3733 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3734 Clemens Ballarin;
  3735 
  3736 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3737 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3738 Rasmussen;
  3739 
  3740 * HOL/Lattice: fundamental concepts of lattice theory and order
  3741 structures, including duals, properties of bounds versus algebraic
  3742 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3743 Theorem for complete lattices etc.; may also serve as a demonstration
  3744 for abstract algebraic reasoning using axiomatic type classes, and
  3745 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3746 
  3747 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3748 von Oheimb;
  3749 
  3750 * HOL/IMPP: extension of IMP with local variables and mutually
  3751 recursive procedures, by David von Oheimb;
  3752 
  3753 * HOL/Lambda: converted into new-style theory and document;
  3754 
  3755 * HOL/ex/Multiquote: example of multiple nested quotations and
  3756 anti-quotations -- basically a generalized version of de-Bruijn
  3757 representation; very useful in avoiding lifting of operations;
  3758 
  3759 * HOL/record: added general record equality rule to simpset; fixed
  3760 select-update simplification procedure to handle extended records as
  3761 well; admit "r" as field name;
  3762 
  3763 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3764 other numeric types and also as the identity of groups, rings, etc.;
  3765 
  3766 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3767 Types nat and int belong to this axclass;
  3768 
  3769 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3770    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3771    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3772   two terms #m*u and #n*u are replaced by #(m+n)*u
  3773     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3774   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3775     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3776 
  3777 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3778 powerful prover for predicate logic but knows nothing of clasets; see
  3779 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3780 
  3781 * HOL: new version of "case_tac" subsumes both boolean case split and
  3782 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3783 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3784 
  3785 * HOL: simplification no longer dives into case-expressions: only the
  3786 selector expression is simplified, but not the remaining arms; to
  3787 enable full simplification of case-expressions for datatype t, you may
  3788 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3789 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3790 
  3791 * HOL/recdef: the recursion equations generated by 'recdef' for
  3792 function 'f' are now called f.simps instead of f.rules; if all
  3793 termination conditions are proved automatically, these simplification
  3794 rules are added to the simpset, as in primrec; rules may be named
  3795 individually as well, resulting in a separate list of theorems for
  3796 each equation;
  3797 
  3798 * HOL/While is a new theory that provides a while-combinator. It
  3799 permits the definition of tail-recursive functions without the
  3800 provision of a termination measure. The latter is necessary once the
  3801 invariant proof rule for while is applied.
  3802 
  3803 * HOL: new (overloaded) notation for the set of elements below/above
  3804 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3805 
  3806 * HOL: theorems impI, allI, ballI bound as "strip";
  3807 
  3808 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3809 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3810 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3811 
  3812 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3813 
  3814 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3815 main HOL, but was unused);
  3816 
  3817 * HOL: fewer consts declared as global (e.g. have to refer to
  3818 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3819 
  3820 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3821 in case of overlap with user translations (e.g. judgements over
  3822 tuples); (note that the underlying logical represenation is still
  3823 bogus);
  3824 
  3825 
  3826 *** ZF ***
  3827 
  3828 * ZF: simplification automatically cancels common terms in arithmetic
  3829 expressions over nat and int;
  3830 
  3831 * ZF: new treatment of nat to minimize type-checking: all operators
  3832 coerce their operands to a natural number using the function natify,
  3833 making the algebraic laws unconditional;
  3834 
  3835 * ZF: as above, for int: operators coerce their operands to an integer
  3836 using the function intify;
  3837 
  3838 * ZF: the integer library now contains many of the usual laws for the
  3839 orderings, including $<=, and monotonicity laws for $+ and $*;
  3840 
  3841 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3842 simplification;
  3843 
  3844 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3845 to the simplifier and classical reasoner simultaneously;
  3846 
  3847 
  3848 *** General ***
  3849 
  3850 * Provers: blast_tac now handles actual object-logic rules as
  3851 assumptions; note that auto_tac uses blast_tac internally as well;
  3852 
  3853 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3854 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3855 
  3856 * Provers: delrules now handles destruct rules as well (no longer need
  3857 explicit make_elim);
  3858 
  3859 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3860   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3861 use instead the strong form,
  3862   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3863 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3864 from destruct-rules;
  3865 
  3866 * Provers: Simplifier.easy_setup provides a fast path to basic
  3867 Simplifier setup for new object-logics;
  3868 
  3869 * Pure: AST translation rules no longer require constant head on LHS;
  3870 
  3871 * Pure: improved name spaces: ambiguous output is qualified; support
  3872 for hiding of names;
  3873 
  3874 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3875 XSYMBOL_HOME; no longer need to do manual configuration in most
  3876 situations;
  3877 
  3878 * system: compression of ML heaps images may now be controlled via -c
  3879 option of isabelle and isatool usedir (currently only observed by
  3880 Poly/ML);
  3881 
  3882 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3883 useful for remote X11);
  3884 
  3885 * system: provide TAGS file for Isabelle sources;
  3886 
  3887 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3888 order;
  3889 
  3890 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3891 timing flag supersedes proof_timing and Toplevel.trace;
  3892 
  3893 * ML: new combinators |>> and |>>> for incremental transformations
  3894 with secondary results (e.g. certain theory extensions):
  3895 
  3896 * ML: PureThy.add_defs gets additional argument to indicate potential
  3897 overloading (usually false);
  3898 
  3899 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3900 results;
  3901 
  3902 
  3903 
  3904 New in Isabelle99 (October 1999)
  3905 --------------------------------
  3906 
  3907 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3908 
  3909 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3910 are no longer simplified.  (This allows the simplifier to unfold recursive
  3911 functional programs.)  To restore the old behaviour, declare
  3912 
  3913     Delcongs [if_weak_cong];
  3914 
  3915 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3916 complement;
  3917 
  3918 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3919 
  3920 * HOL/datatype: mutual_induct_tac no longer exists --
  3921   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3922 
  3923 * HOL/typedef: fixed type inference for representing set; type
  3924 arguments now have to occur explicitly on the rhs as type constraints;
  3925 
  3926 * ZF: The con_defs part of an inductive definition may no longer refer
  3927 to constants declared in the same theory;
  3928 
  3929 * HOL, ZF: the function mk_cases, generated by the inductive
  3930 definition package, has lost an argument.  To simplify its result, it
  3931 uses the default simpset instead of a supplied list of theorems.
  3932 
  3933 * HOL/List: the constructors of type list are now Nil and Cons;
  3934 
  3935 * Simplifier: the type of the infix ML functions
  3936         setSSolver addSSolver setSolver addSolver
  3937 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3938 for packaging solvers. A solver is created via
  3939         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3940 where the string argument is only a comment.
  3941 
  3942 
  3943 *** Proof tools ***
  3944 
  3945 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3946 decision procedure for linear arithmetic. Currently it is used for
  3947 types `nat', `int', and `real' in HOL (see below); it can, should and
  3948 will be instantiated for other types and logics as well.
  3949 
  3950 * The simplifier now accepts rewrite rules with flexible heads, eg
  3951      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3952   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3953   matching.
  3954 
  3955 
  3956 *** General ***
  3957 
  3958 * New Isabelle/Isar subsystem provides an alternative to traditional
  3959 tactical theorem proving; together with the ProofGeneral/isar user
  3960 interface it offers an interactive environment for developing human
  3961 readable proof documents (Isar == Intelligible semi-automated
  3962 reasoning); for further information see isatool doc isar-ref,
  3963 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3964 
  3965 * improved and simplified presentation of theories: better HTML markup
  3966 (including colors), graph views in several sizes; isatool usedir now
  3967 provides a proper interface for user theories (via -P option); actual
  3968 document preparation based on (PDF)LaTeX is available as well (for
  3969 new-style theories only); see isatool doc system for more information;
  3970 
  3971 * native support for Proof General, both for classic Isabelle and
  3972 Isabelle/Isar;
  3973 
  3974 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3975 using the graph browser tool;
  3976 
  3977 * Isabelle manuals now also available as PDF;
  3978 
  3979 * theory loader rewritten from scratch (may not be fully
  3980 bug-compatible); old loadpath variable has been replaced by show_path,
  3981 add_path, del_path, reset_path functions; new operations such as
  3982 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3983 isatool doc ref);
  3984 
  3985 * improved isatool install: option -k creates KDE application icon,
  3986 option -p DIR installs standalone binaries;
  3987 
  3988 * added ML_PLATFORM setting (useful for cross-platform installations);
  3989 more robust handling of platform specific ML images for SML/NJ;
  3990 
  3991 * the settings environment is now statically scoped, i.e. it is never
  3992 created again in sub-processes invoked from isabelle, isatool, or
  3993 Isabelle;
  3994 
  3995 * path element specification '~~' refers to '$ISABELLE_HOME';
  3996 
  3997 * in locales, the "assumes" and "defines" parts may be omitted if
  3998 empty;
  3999 
  4000 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4001 long arrows);
  4002 
  4003 * new print_mode "HTML";
  4004 
  4005 * new flag show_tags controls display of tags of theorems (which are
  4006 basically just comments that may be attached by some tools);
  4007 
  4008 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4009 mode and goal output format:
  4010 
  4011 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4012 244c244
  4013 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4014 ---
  4015 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4016 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4017 181c181
  4018 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4019 ---
  4020 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4021 
  4022 * function bind_thms stores lists of theorems (cf. bind_thm);
  4023 
  4024 * new shorthand tactics ftac, eatac, datac, fatac;
  4025 
  4026 * qed (and friends) now accept "" as result name; in that case the
  4027 theorem is not stored, but proper checks and presentation of the
  4028 result still apply;
  4029 
  4030 * theorem database now also indexes constants "Trueprop", "all",
  4031 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4032 
  4033 
  4034 *** HOL ***
  4035 
  4036 ** HOL arithmetic **
  4037 
  4038 * There are now decision procedures for linear arithmetic over nat and
  4039 int:
  4040 
  4041 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4042 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4043 are treated as atomic; subformulae not involving type `nat' or `int'
  4044 are ignored; quantified subformulae are ignored unless they are
  4045 positive universal or negative existential. The tactic has to be
  4046 invoked by hand and can be a little bit slow. In particular, the
  4047 running time is exponential in the number of occurrences of `min' and
  4048 `max', and `-' on `nat'.
  4049 
  4050 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4051 (negated) (in)equalities among the premises and the conclusion into
  4052 account (i.e. no compound formulae) and does not know about `min' and
  4053 `max', and `-' on `nat'. It is fast and is used automatically by the
  4054 simplifier.
  4055 
  4056 NB: At the moment, these decision procedures do not cope with mixed
  4057 nat/int formulae where the two parts interact, such as `m < n ==>
  4058 int(m) < int(n)'.
  4059 
  4060 * HOL/Numeral provides a generic theory of numerals (encoded
  4061 efficiently as bit strings); setup for types nat/int/real is in place;
  4062 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4063 int, existing theories and proof scripts may require a few additional
  4064 type constraints;
  4065 
  4066 * integer division and remainder can now be performed on constant
  4067 arguments;
  4068 
  4069 * many properties of integer multiplication, division and remainder
  4070 are now available;
  4071 
  4072 * An interface to the Stanford Validity Checker (SVC) is available through the
  4073 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4074 are proved automatically.  SVC must be installed separately, and its results
  4075 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4076 invocation of the underlying oracle).  For SVC see
  4077   http://verify.stanford.edu/SVC
  4078 
  4079 * IsaMakefile: the HOL-Real target now builds an actual image;
  4080 
  4081 
  4082 ** HOL misc **
  4083 
  4084 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4085 (in Isabelle/Isar) -- by Gertrud Bauer;
  4086 
  4087 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4088 analysis for assembly languages with subtypes;
  4089 
  4090 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4091 -- avoids syntactic ambiguities and treats state, transition, and
  4092 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4093 changed syntax and (many) tactics;
  4094 
  4095 * HOL/inductive: Now also handles more general introduction rules such
  4096   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4097   theorems are now maintained within the theory (maintained via the
  4098   "mono" attribute);
  4099 
  4100 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4101   (using function types) such as
  4102 
  4103   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4104 
  4105 * HOL/record: record_simproc (part of the default simpset) takes care
  4106 of selectors applied to updated records; record_split_tac is no longer
  4107 part of the default claset; update_defs may now be removed from the
  4108 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4109 
  4110   claset_ref () := claset() addSWrapper record_split_wrapper;
  4111   Delsimprocs [record_simproc]
  4112 
  4113 * HOL/typedef: fixed type inference for representing set; type
  4114 arguments now have to occur explicitly on the rhs as type constraints;
  4115 
  4116 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4117 names rather than an ML expression;
  4118 
  4119 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4120 supplied later.  Program schemes can be defined, such as
  4121     "While B C s = (if B s then While B C (C s) else s)"
  4122 where the well-founded relation can be chosen after B and C have been given.
  4123 
  4124 * HOL/List: the constructors of type list are now Nil and Cons;
  4125 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4126 course, ML tools referring to List.list.op # etc. have to be adapted;
  4127 
  4128 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4129 disabled by default; run isabelle with option -m HOL to get back to
  4130 the original Gordon/HOL-style output;
  4131 
  4132 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4133 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4134 
  4135 * HOL basic syntax simplified (more orthogonal): all variants of
  4136 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4137 Eps operator is provided as well: "SOME x. P[x]";
  4138 
  4139 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4140 
  4141 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4142 thus available for user theories;
  4143 
  4144 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4145 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4146 time;
  4147 
  4148 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4149 several times and then mp;
  4150 
  4151 
  4152 *** LK ***
  4153 
  4154 * the notation <<...>> is now available as a notation for sequences of
  4155 formulas;
  4156 
  4157 * the simplifier is now installed
  4158 
  4159 * the axiom system has been generalized (thanks to Soren Heilmann)
  4160 
  4161 * the classical reasoner now has a default rule database
  4162 
  4163 
  4164 *** ZF ***
  4165 
  4166 * new primrec section allows primitive recursive functions to be given
  4167 directly (as in HOL) over datatypes and the natural numbers;
  4168 
  4169 * new tactics induct_tac and exhaust_tac for induction (or case
  4170 analysis) over datatypes and the natural numbers;
  4171 
  4172 * the datatype declaration of type T now defines the recursor T_rec;
  4173 
  4174 * simplification automatically does freeness reasoning for datatype
  4175 constructors;
  4176 
  4177 * automatic type-inference, with AddTCs command to insert new
  4178 type-checking rules;
  4179 
  4180 * datatype introduction rules are now added as Safe Introduction rules
  4181 to the claset;
  4182 
  4183 * the syntax "if P then x else y" is now available in addition to
  4184 if(P,x,y);
  4185 
  4186 
  4187 *** Internal programming interfaces ***
  4188 
  4189 * tuned simplifier trace output; new flag debug_simp;
  4190 
  4191 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4192 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4193 
  4194 * AxClass.axclass_tac lost the theory argument;
  4195 
  4196 * tuned current_goals_markers semantics: begin / end goal avoids
  4197 printing empty lines;
  4198 
  4199 * removed prs and prs_fn hook, which was broken because it did not
  4200 include \n in its semantics, forcing writeln to add one
  4201 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4202 string -> unit if you really want to output text without newline;
  4203 
  4204 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4205 plain output, interface builders may have to enable 'isabelle_font'
  4206 mode to get Isabelle font glyphs as before;
  4207 
  4208 * refined token_translation interface; INCOMPATIBILITY: output length
  4209 now of type real instead of int;
  4210 
  4211 * theory loader actions may be traced via new ThyInfo.add_hook
  4212 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4213 your own database of information attached to *whole* theories -- as
  4214 opposed to intra-theory data slots offered via TheoryDataFun;
  4215 
  4216 * proper handling of dangling sort hypotheses (at last!);
  4217 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4218 extra sort hypotheses that can be witnessed from the type signature;
  4219 the force_strip_shyps flag is gone, any remaining shyps are simply
  4220 left in the theorem (with a warning issued by strip_shyps_warning);
  4221 
  4222 
  4223 
  4224 New in Isabelle98-1 (October 1998)
  4225 ----------------------------------
  4226 
  4227 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4228 
  4229 * several changes of automated proof tools;
  4230 
  4231 * HOL: major changes to the inductive and datatype packages, including
  4232 some minor incompatibilities of theory syntax;
  4233 
  4234 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4235 called `inj_on';
  4236 
  4237 * HOL: removed duplicate thms in Arith:
  4238   less_imp_add_less  should be replaced by  trans_less_add1
  4239   le_imp_add_le      should be replaced by  trans_le_add1
  4240 
  4241 * HOL: unary minus is now overloaded (new type constraints may be
  4242 required);
  4243 
  4244 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4245 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4246 now taken as an integer constant.
  4247 
  4248 * Pure: ML function 'theory_of' renamed to 'theory';
  4249 
  4250 
  4251 *** Proof tools ***
  4252 
  4253 * Simplifier:
  4254   1. Asm_full_simp_tac is now more aggressive.
  4255      1. It will sometimes reorient premises if that increases their power to
  4256         simplify.
  4257      2. It does no longer proceed strictly from left to right but may also
  4258         rotate premises to achieve further simplification.
  4259      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4260      old Asm_full_simp_tac in that it does not rotate premises.
  4261   2. The simplifier now knows a little bit about nat-arithmetic.
  4262 
  4263 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4264 allows for selected deletion of wrappers, by introduction of names for
  4265 wrapper functionals.  This implies that addbefore, addSbefore,
  4266 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4267 and that adding two tactics with the same name overwrites the first
  4268 one (emitting a warning).
  4269   type wrapper = (int -> tactic) -> (int -> tactic)
  4270   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4271   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4272   delWrapper, delSWrapper: claset *  string            -> claset
  4273   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4274 
  4275 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4276 semantics; addbefore now affects only the unsafe part of step_tac
  4277 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4278 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4279 by Force_tac;
  4280 
  4281 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4282 compWrapper; added safe wrapper (and access functions for it);
  4283 
  4284 * HOL/split_all_tac is now much faster and fails if there is nothing
  4285 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4286 and the names of the automatically generated variables have changed.
  4287 split_all_tac has moved within claset() from unsafe wrappers to safe
  4288 wrappers, which means that !!-bound variables are split much more
  4289 aggressively, and safe_tac and clarify_tac now split such variables.
  4290 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4291 Note: the same holds for record_split_tac, which does the job of
  4292 split_all_tac for record fields.
  4293 
  4294 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4295 permanently to the default simpset using Addsplits just like
  4296 Addsimps. They can be removed via Delsplits just like
  4297 Delsimps. Lower-case versions are also available.
  4298 
  4299 * HOL/Simplifier: The rule split_if is now part of the default
  4300 simpset. This means that the simplifier will eliminate all occurrences
  4301 of if-then-else in the conclusion of a goal. To prevent this, you can
  4302 either remove split_if completely from the default simpset by
  4303 `Delsplits [split_if]' or remove it in a specific call of the
  4304 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4305 other case splitting rules to/from the default simpset: every datatype
  4306 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4307 t is the name of the datatype).
  4308 
  4309 * Classical reasoner / Simplifier combination: new force_tac (and
  4310 derivatives Force_tac, force) combines rewriting and classical
  4311 reasoning (and whatever other tools) similarly to auto_tac, but is
  4312 aimed to solve the given subgoal completely.
  4313 
  4314 
  4315 *** General ***
  4316 
  4317 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4318 and `goalw': the theory is no longer needed as an explicit argument -
  4319 the current theory context is used; assumptions are no longer returned
  4320 at the ML-level unless one of them starts with ==> or !!; it is
  4321 recommended to convert to these new commands using isatool fixgoal
  4322 (backup your sources first!);
  4323 
  4324 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4325 the current theory context, and 'theory' to lookup stored theories;
  4326 
  4327 * new theory section 'locale' for declaring constants, assumptions and
  4328 definitions that have local scope;
  4329 
  4330 * new theory section 'nonterminals' for purely syntactic types;
  4331 
  4332 * new theory section 'setup' for generic ML setup functions
  4333 (e.g. package initialization);
  4334 
  4335 * the distribution now includes Isabelle icons: see
  4336 lib/logo/isabelle-{small,tiny}.xpm;
  4337 
  4338 * isatool install - install binaries with absolute references to
  4339 ISABELLE_HOME/bin;
  4340 
  4341 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4342 
  4343 * print mode 'emacs' reserved for Isamode;
  4344 
  4345 * support multiple print (ast) translations per constant name;
  4346 
  4347 * theorems involving oracles are now printed with a suffixed [!];
  4348 
  4349 
  4350 *** HOL ***
  4351 
  4352 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4353 
  4354 * HOL/inductive package reorganized and improved: now supports mutual
  4355 definitions such as
  4356 
  4357   inductive EVEN ODD
  4358     intrs
  4359       null "0 : EVEN"
  4360       oddI "n : EVEN ==> Suc n : ODD"
  4361       evenI "n : ODD ==> Suc n : EVEN"
  4362 
  4363 new theorem list "elims" contains an elimination rule for each of the
  4364 recursive sets; inductive definitions now handle disjunctive premises
  4365 correctly (also ZF);
  4366 
  4367 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4368 "mutual_induct" no longer exists - the induction rule is always
  4369 contained in "induct";
  4370 
  4371 
  4372 * HOL/datatype package re-implemented and greatly improved: now
  4373 supports mutually recursive datatypes such as
  4374 
  4375   datatype
  4376     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4377             | SUM ('a aexp) ('a aexp)
  4378             | DIFF ('a aexp) ('a aexp)
  4379             | NUM 'a
  4380   and
  4381     'a bexp = LESS ('a aexp) ('a aexp)
  4382             | AND ('a bexp) ('a bexp)
  4383             | OR ('a bexp) ('a bexp)
  4384 
  4385 as well as indirectly recursive datatypes such as
  4386 
  4387   datatype
  4388     ('a, 'b) term = Var 'a
  4389                   | App 'b ((('a, 'b) term) list)
  4390 
  4391 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4392 induction on mutually / indirectly recursive datatypes.
  4393 
  4394 Primrec equations are now stored in theory and can be accessed via
  4395 <function_name>.simps.
  4396 
  4397 INCOMPATIBILITIES:
  4398 
  4399   - Theories using datatypes must now have theory Datatype as an
  4400     ancestor.
  4401   - The specific <typename>.induct_tac no longer exists - use the
  4402     generic induct_tac instead.
  4403   - natE has been renamed to nat.exhaust - use exhaust_tac
  4404     instead of res_inst_tac ... natE. Note that the variable
  4405     names in nat.exhaust differ from the names in natE, this
  4406     may cause some "fragile" proofs to fail.
  4407   - The theorems split_<typename>_case and split_<typename>_case_asm
  4408     have been renamed to <typename>.split and <typename>.split_asm.
  4409   - Since default sorts of type variables are now handled correctly,
  4410     some datatype definitions may have to be annotated with explicit
  4411     sort constraints.
  4412   - Primrec definitions no longer require function name and type
  4413     of recursive argument.
  4414 
  4415 Consider using isatool fixdatatype to adapt your theories and proof
  4416 scripts to the new package (backup your sources first!).
  4417 
  4418 
  4419 * HOL/record package: considerably improved implementation; now
  4420 includes concrete syntax for record types, terms, updates; theorems
  4421 for surjective pairing and splitting !!-bound record variables; proof
  4422 support is as follows:
  4423 
  4424   1) standard conversions (selectors or updates applied to record
  4425 constructor terms) are part of the standard simpset;
  4426 
  4427   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4428 made part of standard simpset and claset via addIffs;
  4429 
  4430   3) a tactic for record field splitting (record_split_tac) is part of
  4431 the standard claset (addSWrapper);
  4432 
  4433 To get a better idea about these rules you may retrieve them via
  4434 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4435 the name of your record type.
  4436 
  4437 The split tactic 3) conceptually simplifies by the following rule:
  4438 
  4439   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4440 
  4441 Thus any record variable that is bound by meta-all will automatically
  4442 blow up into some record constructor term, consequently the
  4443 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4444 solve record problems automatically.
  4445 
  4446 
  4447 * reorganized the main HOL image: HOL/Integ and String loaded by
  4448 default; theory Main includes everything;
  4449 
  4450 * automatic simplification of integer sums and comparisons, using cancellation;
  4451 
  4452 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4453 
  4454 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4455 
  4456 * many new identities for unions, intersections, set difference, etc.;
  4457 
  4458 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4459 called split_if, split_split, split_sum_case and split_nat_case (to go
  4460 with add/delsplits);
  4461 
  4462 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4463 (?x::unit) = (); this is made part of the default simpset, which COULD
  4464 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4465 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4466 unit_abs_eta_conv is added in order to counter the effect of
  4467 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4468 %u.f();
  4469 
  4470 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4471 makes more sense);
  4472 
  4473 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4474   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4475   disjointness reasoning but breaking a few old proofs.
  4476 
  4477 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4478 to 'converse' from 'inverse' (for compatibility with ZF and some
  4479 literature);
  4480 
  4481 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4482 the well-founded relation;
  4483 
  4484 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4485     Compl A.  The "Compl" syntax remains available as input syntax for this
  4486     release ONLY.
  4487 
  4488 * HOL/Update: new theory of function updates:
  4489     f(a:=b) == %x. if x=a then b else f x
  4490 may also be iterated as in f(a:=b,c:=d,...);
  4491 
  4492 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4493 
  4494 * HOL/List:
  4495   - new function list_update written xs[i:=v] that updates the i-th
  4496     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4497   - new function `upt' written [i..j(] which generates the list
  4498     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4499     bound write [i..j], which is a shorthand for [i..j+1(].
  4500   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4501 
  4502 * HOL/Arith:
  4503   - removed 'pred' (predecessor) function;
  4504   - generalized some theorems about n-1;
  4505   - many new laws about "div" and "mod";
  4506   - new laws about greatest common divisors (see theory ex/Primes);
  4507 
  4508 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4509 instead of "inverse";
  4510 
  4511 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4512   of the multiset ordering;
  4513 
  4514 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4515   (not included by default);
  4516 
  4517 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4518 
  4519 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4520   programs, i.e. different program variables may have different types.
  4521 
  4522 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4523   [previously, this check worked only if the rewrite rule was unconditional]
  4524   Now rew can involve either definitions or equalities (either == or =).
  4525 
  4526 
  4527 *** ZF ***
  4528 
  4529 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4530   only the theorems proved on ZF.ML;
  4531 
  4532 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4533   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4534   disjointness reasoning but breaking a few old proofs.
  4535 
  4536 * ZF/Update: new theory of function updates
  4537     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4538   may also be iterated as in f(a:=b,c:=d,...);
  4539 
  4540 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4541 
  4542 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4543   [previously, this check worked only if the rewrite rule was unconditional]
  4544   Now rew can involve either definitions or equalities (either == or =).
  4545 
  4546 * case_tac provided for compatibility with HOL
  4547     (like the old excluded_middle_tac, but with subgoals swapped)
  4548 
  4549 
  4550 *** Internal programming interfaces ***
  4551 
  4552 * Pure: several new basic modules made available for general use, see
  4553 also src/Pure/README;
  4554 
  4555 * improved the theory data mechanism to support encapsulation (data
  4556 kind name replaced by private Object.kind, acting as authorization
  4557 key); new type-safe user interface via functor TheoryDataFun; generic
  4558 print_data function becomes basically useless;
  4559 
  4560 * removed global_names compatibility flag -- all theory declarations
  4561 are qualified by default;
  4562 
  4563 * module Pure/Syntax now offers quote / antiquote translation
  4564 functions (useful for Hoare logic etc. with implicit dependencies);
  4565 see HOL/ex/Antiquote for an example use;
  4566 
  4567 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4568 cterm -> thm;
  4569 
  4570 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4571 subgoal;
  4572 
  4573 * Display.print_goals function moved to Locale.print_goals;
  4574 
  4575 * standard print function for goals supports current_goals_markers
  4576 variable for marking begin of proof, end of proof, start of goal; the
  4577 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4578 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4579 for example;
  4580 
  4581 
  4582 
  4583 New in Isabelle98 (January 1998)
  4584 --------------------------------
  4585 
  4586 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4587 
  4588 * changed lexical syntax of terms / types: dots made part of long
  4589 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4590 
  4591 * simpset (and claset) reference variable replaced by functions
  4592 simpset / simpset_ref;
  4593 
  4594 * no longer supports theory aliases (via merge) and non-trivial
  4595 implicit merge of thms' signatures;
  4596 
  4597 * most internal names of constants changed due to qualified names;
  4598 
  4599 * changed Pure/Sequence interface (see Pure/seq.ML);
  4600 
  4601 
  4602 *** General Changes ***
  4603 
  4604 * hierachically structured name spaces (for consts, types, axms, thms
  4605 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4606 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4607 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4608 long_names for fully qualified output names; NOTE: ML programs
  4609 (special tactics, packages etc.) referring to internal names may have
  4610 to be adapted to cope with fully qualified names; in case of severe
  4611 backward campatibility problems try setting 'global_names' at compile
  4612 time to have enrything declared within a flat name space; one may also
  4613 fine tune name declarations in theories via the 'global' and 'local'
  4614 section;
  4615 
  4616 * reimplemented the implicit simpset and claset using the new anytype
  4617 data filed in signatures; references simpset:simpset ref etc. are
  4618 replaced by functions simpset:unit->simpset and
  4619 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4620 to patch your ML files accordingly;
  4621 
  4622 * HTML output now includes theory graph data for display with Java
  4623 applet or isatool browser; data generated automatically via isatool
  4624 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4625 
  4626 * defs may now be conditional; improved rewrite_goals_tac to handle
  4627 conditional equations;
  4628 
  4629 * defs now admits additional type arguments, using TYPE('a) syntax;
  4630 
  4631 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4632 creates a new theory node; implicit merge of thms' signatures is
  4633 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4634 transfer:theory->thm->thm in (rare) cases;
  4635 
  4636 * improved handling of draft signatures / theories; draft thms (and
  4637 ctyps, cterms) are automatically promoted to real ones;
  4638 
  4639 * slightly changed interfaces for oracles: admit many per theory, named
  4640 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4641 
  4642 * print_goals: optional output of const types (set show_consts and
  4643 show_types);
  4644 
  4645 * improved output of warnings (###) and errors (***);
  4646 
  4647 * subgoal_tac displays a warning if the new subgoal has type variables;
  4648 
  4649 * removed old README and Makefiles;
  4650 
  4651 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4652 
  4653 * removed obsolete init_pps and init_database;
  4654 
  4655 * deleted the obsolete tactical STATE, which was declared by
  4656     fun STATE tacfun st = tacfun st st;
  4657 
  4658 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4659 (which abbreviates $HOME);
  4660 
  4661 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4662 use isatool fixseq to adapt your ML programs (this works for fully
  4663 qualified references to the Sequence structure only!);
  4664 
  4665 * use_thy no longer requires writable current directory; it always
  4666 reloads .ML *and* .thy file, if either one is out of date;
  4667 
  4668 
  4669 *** Classical Reasoner ***
  4670 
  4671 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4672 tactics that use classical reasoning to simplify a subgoal without
  4673 splitting it into several subgoals;
  4674 
  4675 * Safe_tac: like safe_tac but uses the default claset;
  4676 
  4677 
  4678 *** Simplifier ***
  4679 
  4680 * added simplification meta rules:
  4681     (asm_)(full_)simplify: simpset -> thm -> thm;
  4682 
  4683 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4684 logics (again);
  4685 
  4686 * added prems argument to simplification procedures;
  4687 
  4688 * HOL, FOL, ZF: added infix function `addsplits':
  4689   instead of `<simpset> setloop (split_tac <thms>)'
  4690   you can simply write `<simpset> addsplits <thms>'
  4691 
  4692 
  4693 *** Syntax ***
  4694 
  4695 * TYPE('a) syntax for type reflection terms;
  4696 
  4697 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4698 
  4699 * pretty printer: changed order of mixfix annotation preference (again!);
  4700 
  4701 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4702 
  4703 
  4704 *** HOL ***
  4705 
  4706 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4707   with `addloop' of the simplifier to faciliate case splitting in premises.
  4708 
  4709 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4710 
  4711 * HOL/Auth: new protocol proofs including some for the Internet
  4712   protocol TLS;
  4713 
  4714 * HOL/Map: new theory of `maps' a la VDM;
  4715 
  4716 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4717 cancelling out common nat summands from =, <, <= (in)equalities, or
  4718 differences; simplification procedures nat_cancel_factor for
  4719 cancelling common factor from =, <, <= (in)equalities over natural
  4720 sums; nat_cancel contains both kinds of procedures, it is installed by
  4721 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4722 
  4723 * HOL/simplifier: terms of the form
  4724   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4725   are rewritten to
  4726   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4727   and those of the form
  4728   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4729   are rewritten to
  4730   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4731 
  4732 * HOL/datatype
  4733   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4734 
  4735   P(t_case f1 ... fn x) =
  4736      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4737         ...
  4738        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4739      )
  4740 
  4741   and a theorem `split_t_case_asm' of the form
  4742 
  4743   P(t_case f1 ... fn x) =
  4744     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4745         ...
  4746        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4747      )
  4748   which can be added to a simpset via `addsplits'. The existing theorems
  4749   expand_list_case and expand_option_case have been renamed to
  4750   split_list_case and split_option_case.
  4751 
  4752 * HOL/Arithmetic:
  4753   - `pred n' is automatically converted to `n-1'.
  4754     Users are strongly encouraged not to use `pred' any longer,
  4755     because it will disappear altogether at some point.
  4756   - Users are strongly encouraged to write "0 < n" rather than
  4757     "n ~= 0". Theorems and proof tools have been modified towards this
  4758     `standard'.
  4759 
  4760 * HOL/Lists:
  4761   the function "set_of_list" has been renamed "set" (and its theorems too);
  4762   the function "nth" now takes its arguments in the reverse order and
  4763   has acquired the infix notation "!" as in "xs!n".
  4764 
  4765 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4766 
  4767 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4768   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4769 
  4770 * HOL/record: extensible records with schematic structural subtyping
  4771 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4772 still lacks various theorems and concrete record syntax;
  4773 
  4774 
  4775 *** HOLCF ***
  4776 
  4777 * removed "axioms" and "generated by" sections;
  4778 
  4779 * replaced "ops" section by extended "consts" section, which is capable of
  4780   handling the continuous function space "->" directly;
  4781 
  4782 * domain package:
  4783   . proves theorems immediately and stores them in the theory,
  4784   . creates hierachical name space,
  4785   . now uses normal mixfix annotations (instead of cinfix...),
  4786   . minor changes to some names and values (for consistency),
  4787   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4788   . separator between mutual domain defs: changed "," to "and",
  4789   . improved handling of sort constraints;  now they have to
  4790     appear on the left-hand side of the equations only;
  4791 
  4792 * fixed LAM <x,y,zs>.b syntax;
  4793 
  4794 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4795 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4796 
  4797 
  4798 *** FOL and ZF ***
  4799 
  4800 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4801   with `addloop' of the simplifier to faciliate case splitting in premises.
  4802 
  4803 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4804 in HOL, they strip ALL and --> from proved theorems;
  4805 
  4806 
  4807 
  4808 New in Isabelle94-8 (May 1997)
  4809 ------------------------------
  4810 
  4811 *** General Changes ***
  4812 
  4813 * new utilities to build / run / maintain Isabelle etc. (in parts
  4814 still somewhat experimental); old Makefiles etc. still functional;
  4815 
  4816 * new 'Isabelle System Manual';
  4817 
  4818 * INSTALL text, together with ./configure and ./build scripts;
  4819 
  4820 * reimplemented type inference for greater efficiency, better error
  4821 messages and clean internal interface;
  4822 
  4823 * prlim command for dealing with lots of subgoals (an easier way of
  4824 setting goals_limit);
  4825 
  4826 
  4827 *** Syntax ***
  4828 
  4829 * supports alternative (named) syntax tables (parser and pretty
  4830 printer); internal interface is provided by add_modesyntax(_i);
  4831 
  4832 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4833 be used in conjunction with the Isabelle symbol font; uses the
  4834 "symbols" syntax table;
  4835 
  4836 * added token_translation interface (may translate name tokens in
  4837 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4838 the current print_mode); IMPORTANT: user print translation functions
  4839 are responsible for marking newly introduced bounds
  4840 (Syntax.mark_boundT);
  4841 
  4842 * token translations for modes "xterm" and "xterm_color" that display
  4843 names in bold, underline etc. or colors (which requires a color
  4844 version of xterm);
  4845 
  4846 * infixes may now be declared with names independent of their syntax;
  4847 
  4848 * added typed_print_translation (like print_translation, but may
  4849 access type of constant);
  4850 
  4851 
  4852 *** Classical Reasoner ***
  4853 
  4854 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4855 some limitations.  Blast_tac...
  4856   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4857   + ignores elimination rules that don't have the correct format
  4858         (the conclusion MUST be a formula variable)
  4859   + ignores types, which can make HOL proofs fail
  4860   + rules must not require higher-order unification, e.g. apply_type in ZF
  4861     [message "Function Var's argument not a bound variable" relates to this]
  4862   + its proof strategy is more general but can actually be slower
  4863 
  4864 * substitution with equality assumptions no longer permutes other
  4865 assumptions;
  4866 
  4867 * minor changes in semantics of addafter (now called addaltern); renamed
  4868 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4869 (and access functions for it);
  4870 
  4871 * improved combination of classical reasoner and simplifier:
  4872   + functions for handling clasimpsets
  4873   + improvement of addss: now the simplifier is called _after_ the
  4874     safe steps.
  4875   + safe variant of addss called addSss: uses safe simplifications
  4876     _during_ the safe steps. It is more complete as it allows multiple
  4877     instantiations of unknowns (e.g. with slow_tac).
  4878 
  4879 *** Simplifier ***
  4880 
  4881 * added interface for simplification procedures (functions that
  4882 produce *proven* rewrite rules on the fly, depending on current
  4883 redex);
  4884 
  4885 * ordering on terms as parameter (used for ordered rewriting);
  4886 
  4887 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4888 
  4889 * the solver is now split into a safe and an unsafe part.
  4890 This should be invisible for the normal user, except that the
  4891 functions setsolver and addsolver have been renamed to setSolver and
  4892 addSolver; added safe_asm_full_simp_tac;
  4893 
  4894 
  4895 *** HOL ***
  4896 
  4897 * a generic induction tactic `induct_tac' which works for all datatypes and
  4898 also for type `nat';
  4899 
  4900 * a generic case distinction tactic `exhaust_tac' which works for all
  4901 datatypes and also for type `nat';
  4902 
  4903 * each datatype comes with a function `size';
  4904 
  4905 * patterns in case expressions allow tuple patterns as arguments to
  4906 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4907 
  4908 * primrec now also works with type nat;
  4909 
  4910 * recdef: a new declaration form, allows general recursive functions to be
  4911 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4912 
  4913 * the constant for negation has been renamed from "not" to "Not" to
  4914 harmonize with FOL, ZF, LK, etc.;
  4915 
  4916 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4917 infinite lists;
  4918 
  4919 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4920 
  4921 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4922 problems in commutative rings, using axiomatic type classes for + and *;
  4923 
  4924 * more examples in HOL/MiniML and HOL/Auth;
  4925 
  4926 * more default rewrite rules for quantifiers, union/intersection;
  4927 
  4928 * a new constant `arbitrary == @x.False';
  4929 
  4930 * HOLCF/IOA replaces old HOL/IOA;
  4931 
  4932 * HOLCF changes: derived all rules and arities
  4933   + axiomatic type classes instead of classes
  4934   + typedef instead of faking type definitions
  4935   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4936   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4937   + eliminated the types void, one, tr
  4938   + use unit lift and bool lift (with translations) instead of one and tr
  4939   + eliminated blift from Lift3.thy (use Def instead of blift)
  4940   all eliminated rules are derived as theorems --> no visible changes ;
  4941 
  4942 
  4943 *** ZF ***
  4944 
  4945 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4946 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4947 as ZF_cs addSIs [equalityI];
  4948 
  4949 
  4950 
  4951 New in Isabelle94-7 (November 96)
  4952 ---------------------------------
  4953 
  4954 * allowing negative levels (as offsets) in prlev and choplev;
  4955 
  4956 * super-linear speedup for large simplifications;
  4957 
  4958 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4959 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4960 FAIL); can suppress it using the command Delsimps (ex_simps @
  4961 all_simps); De Morgan laws are also now included, by default;
  4962 
  4963 * improved printing of ==>  :  ~:
  4964 
  4965 * new object-logic "Sequents" adds linear logic, while replacing LK
  4966 and Modal (thanks to Sara Kalvala);
  4967 
  4968 * HOL/Auth: correctness proofs for authentication protocols;
  4969 
  4970 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4971 examples on HOL/Auth);
  4972 
  4973 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4974 the rewriter and classical reasoner simultaneously;
  4975 
  4976 * function uresult no longer returns theorems in "standard" format;
  4977 regain previous version by: val uresult = standard o uresult;
  4978 
  4979 
  4980 
  4981 New in Isabelle94-6
  4982 -------------------
  4983 
  4984 * oracles -- these establish an interface between Isabelle and trusted
  4985 external reasoners, which may deliver results as theorems;
  4986 
  4987 * proof objects (in particular record all uses of oracles);
  4988 
  4989 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4990 
  4991 * "constdefs" section in theory files;
  4992 
  4993 * "primrec" section (HOL) no longer requires names;
  4994 
  4995 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4996 
  4997 
  4998 
  4999 New in Isabelle94-5
  5000 -------------------
  5001 
  5002 * reduced space requirements;
  5003 
  5004 * automatic HTML generation from theories;
  5005 
  5006 * theory files no longer require "..." (quotes) around most types;
  5007 
  5008 * new examples, including two proofs of the Church-Rosser theorem;
  5009 
  5010 * non-curried (1994) version of HOL is no longer distributed;
  5011 
  5012 
  5013 
  5014 New in Isabelle94-4
  5015 -------------------
  5016 
  5017 * greatly reduced space requirements;
  5018 
  5019 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5020 
  5021 * searchable theorem database (see the section "Retrieving theorems" on
  5022 page 8 of the Reference Manual);
  5023 
  5024 * new examples, including Grabczewski's monumental case study of the
  5025 Axiom of Choice;
  5026 
  5027 * The previous version of HOL renamed to Old_HOL;
  5028 
  5029 * The new version of HOL (previously called CHOL) uses a curried syntax
  5030 for functions.  Application looks like f a b instead of f(a,b);
  5031 
  5032 * Mutually recursive inductive definitions finally work in HOL;
  5033 
  5034 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5035 translates to the operator "split";
  5036 
  5037 
  5038 
  5039 New in Isabelle94-3
  5040 -------------------
  5041 
  5042 * new infix operator, addss, allowing the classical reasoner to
  5043 perform simplification at each step of its search.  Example:
  5044         fast_tac (cs addss ss)
  5045 
  5046 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5047 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5048 look like (a,b) instead of <a,b>;
  5049 
  5050 * PLEASE NOTE: CHOL will eventually replace HOL!
  5051 
  5052 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5053 It translates to the operator "split".  A new theory of integers is available;
  5054 
  5055 * In ZF, integer numerals now denote two's-complement binary integers.
  5056 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5057 
  5058 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5059 of the Axiom of Choice;
  5060 
  5061 
  5062 
  5063 New in Isabelle94-2
  5064 -------------------
  5065 
  5066 * Significantly faster resolution;
  5067 
  5068 * the different sections in a .thy file can now be mixed and repeated
  5069 freely;
  5070 
  5071 * Database of theorems for FOL, HOL and ZF.  New
  5072 commands including qed, qed_goal and bind_thm store theorems in the database.
  5073 
  5074 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5075 a given theory (thms_of), or find out what theory a theorem was proved in
  5076 (theory_of_thm);
  5077 
  5078 * Bugs fixed in the inductive definition and datatype packages;
  5079 
  5080 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5081 and HOL_dup_cs obsolete;
  5082 
  5083 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5084 have been removed;
  5085 
  5086 * Simpler definition of function space in ZF;
  5087 
  5088 * new results about cardinal and ordinal arithmetic in ZF;
  5089 
  5090 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5091 types;
  5092 
  5093 :mode=text:wrap=hard:maxLineLen=72:
  5094 $Id$