NEWS
author ballarin
Mon Jul 23 13:50:31 2007 +0200 (2007-07-23)
changeset 23920 4288dc7dc248
parent 23889 1794f405eacc
child 23971 e6d505d5b03d
permissions -rw-r--r--
interpretation: unfolding of equations;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * More uniform information about legacy features, notably a
    10 warning/error of "Legacy feature: ...", depending on the state of the
    11 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
    12 legacy features will disappear eventually.
    13 
    14 * Theory syntax: the header format ``theory A = B + C:'' has been
    15 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    16 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    17 
    18 * Theory syntax: the old non-Isar theory file format has been
    19 discontinued altogether.  Note that ML proof scripts may still be used
    20 with Isar theories; migration is usually quite simple with the ML
    21 function use_legacy_bindings.  INCOMPATIBILITY.
    22 
    23 * Theory syntax: some popular names (e.g. 'class', 'declaration',
    24 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
    25 quotes.
    26 
    27 * Theory loader: be more serious about observing the static theory
    28 header specifications (including optional directories), but not the
    29 accidental file locations of previously successful loads.  Potential
    30 INCOMPATIBILITY, may need to refine theory headers.
    31 
    32 * Theory loader: optional support for content-based file
    33 identification, instead of the traditional scheme of full physical
    34 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
    35 (cf. the system manual).  The new scheme allows to work with
    36 non-finished theories in persistent session images, such that source
    37 files may be moved later on without requiring reloads.
    38 
    39 * Legacy goal package: reduced interface to the bare minimum required
    40 to keep existing proof scripts running.  Most other user-level
    41 functions are now part of the OldGoals structure, which is *not* open
    42 by default (consider isatool expandshort before open OldGoals).
    43 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    44 these tend to cause confusion about the actual goal (!) context being
    45 used here, which is not necessarily the same as the_context().
    46 
    47 * Command 'find_theorems': supports "*" wild-card in "name:"
    48 criterion; "with_dups" option.  Certain ProofGeneral versions might
    49 support a specific search form (see ProofGeneral/CHANGES).
    50 
    51 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    52 by default, which means that "prems" (and also "fixed variables") are
    53 suppressed from proof state output.  Note that the ProofGeneral
    54 settings mechanism allows to change and save options persistently, but
    55 older versions of Isabelle will fail to start up if a negative prems
    56 limit is imposed.
    57 
    58 * Local theory targets may be specified by non-nested blocks of
    59 ``context/locale/class ... begin'' followed by ``end''.  The body may
    60 contain definitions, theorems etc., including any derived mechanism
    61 that has been implemented on top of these primitives.  This concept
    62 generalizes the existing ``theorem (in ...)'' towards more versatility
    63 and scalability.
    64 
    65 * Proof General interface: proper undo of final 'end' command;
    66 discontinued Isabelle/classic mode (ML proof scripts).
    67 
    68 
    69 *** Document preparation ***
    70 
    71 * Added antiquotation @{theory name} which prints the given name,
    72 after checking that it refers to a valid ancestor theory in the
    73 current context.
    74 
    75 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    76 check the given source text as ML type/structure, printing verbatim.
    77 
    78 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    79 "c args == rhs" given in the current context.  (Any number of
    80 arguments may be given on the LHS.)
    81 
    82 
    83 
    84 *** Pure ***
    85 
    86 * code generator: consts in 'consts_code' Isar commands are now referred
    87   to by usual term syntax (including optional type annotations).
    88 
    89 * code generator: 
    90   - Isar 'definition's, 'constdef's and primitive instance definitions are added
    91     explicitly to the table of defining equations
    92   - primitive definitions are not used as defining equations by default any longer
    93   - defining equations are now definitly restricted to meta "==" and object
    94         equality "="
    95   - HOL theories have been adopted accordingly
    96 
    97 * class_package.ML offers a combination of axclasses and locales to
    98 achieve Haskell-like type classes in Isabelle.  See
    99 HOL/ex/Classpackage.thy for examples.
   100 
   101 * Yet another code generator framework allows to generate executable
   102 code for ML and Haskell (including "class"es).  A short usage sketch:
   103 
   104     internal compilation:
   105         code_gen <list of constants (term syntax)> in SML
   106     writing SML code to a file:
   107         code_gen <list of constants (term syntax)> in SML <filename>
   108     writing OCaml code to a file:
   109         code_gen <list of constants (term syntax)> in OCaml <filename>
   110     writing Haskell code to a bunch of files:
   111         code_gen <list of constants (term syntax)> in Haskell <filename>
   112 
   113 Reasonable default setup of framework in HOL/Main.
   114 
   115 Theorem attributs for selecting and transforming function equations theorems:
   116 
   117     [code fun]:        select a theorem as function equation for a specific constant
   118     [code fun del]:    deselect a theorem as function equation for a specific constant
   119     [code inline]:     select an equation theorem for unfolding (inlining) in place
   120     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   121 
   122 User-defined serializations (target in {SML, OCaml, Haskell}):
   123 
   124     code_const <and-list of constants (term syntax)>
   125       {(target) <and-list of const target syntax>}+
   126 
   127     code_type <and-list of type constructors>
   128       {(target) <and-list of type target syntax>}+
   129 
   130     code_instance <and-list of instances>
   131       {(target)}+
   132         where instance ::= <type constructor> :: <class>
   133 
   134     code_class <and_list of classes>
   135       {(target) <and-list of class target syntax>}+
   136         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   137 
   138 code_instance and code_class only apply to target Haskell.
   139 
   140 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   141 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   142 
   143 * Command 'no_translations' removes translation rules from theory
   144 syntax.
   145 
   146 * Overloaded definitions are now actually checked for acyclic
   147 dependencies.  The overloading scheme is slightly more general than
   148 that of Haskell98, although Isabelle does not demand an exact
   149 correspondence to type class and instance declarations.
   150 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   151 exotic versions of overloading -- at the discretion of the user!
   152 
   153 Polymorphic constants are represented via type arguments, i.e. the
   154 instantiation that matches an instance against the most general
   155 declaration given in the signature.  For example, with the declaration
   156 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   157 as c(nat).  Overloading is essentially simultaneous structural
   158 recursion over such type arguments.  Incomplete specification patterns
   159 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   160 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   161 Command 'print_theory' outputs the normalized system of recursive
   162 equations, see section "definitions".
   163 
   164 * Isar: method "assumption" (and implicit closing of subproofs) now
   165 takes simple non-atomic goal assumptions into account: after applying
   166 an assumption as a rule the resulting subgoals are solved by atomic
   167 assumption steps.  This is particularly useful to finish 'obtain'
   168 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   169 without referring to the original premise "!!x. P x ==> thesis" in the
   170 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   171 more permissive.
   172 
   173 * Isar: implicit use of prems from the Isar proof context is
   174 considered a legacy feature.  Common applications like ``have A .''
   175 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   176 referencing facts explicitly here improves readability and
   177 maintainability of proof texts.
   178 
   179 * Isar: improper proof element 'guess' is like 'obtain', but derives
   180 the obtained context from the course of reasoning!  For example:
   181 
   182   assume "EX x y. A x & B y"   -- "any previous fact"
   183   then guess x and y by clarify
   184 
   185 This technique is potentially adventurous, depending on the facts and
   186 proof tools being involved here.
   187 
   188 * Isar: known facts from the proof context may be specified as literal
   189 propositions, using ASCII back-quote syntax.  This works wherever
   190 named facts used to be allowed so far, in proof commands, proof
   191 methods, attributes etc.  Literal facts are retrieved from the context
   192 according to unification of type and term parameters.  For example,
   193 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   194 theorems in the current context, then these are valid literal facts:
   195 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   196 
   197 There is also a proof method "fact" which does the same composition
   198 for explicit goal states, e.g. the following proof texts coincide with
   199 certain special cases of literal facts:
   200 
   201   have "A" by fact                 ==  note `A`
   202   have "A ==> B" by fact           ==  note `A ==> B`
   203   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   204   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   205 
   206 * Isar: ":" (colon) is no longer a symbolic identifier character in
   207 outer syntax.  Thus symbolic identifiers may be used without
   208 additional white space in declarations like this: ``assume *: A''.
   209 
   210 * Isar: 'print_facts' prints all local facts of the current context,
   211 both named and unnamed ones.
   212 
   213 * Isar: 'def' now admits simultaneous definitions, e.g.:
   214 
   215   def x == "t" and y == "u"
   216 
   217 * Isar: added command 'unfolding', which is structurally similar to
   218 'using', but affects both the goal state and facts by unfolding given
   219 rewrite rules.  Thus many occurrences of the 'unfold' method or
   220 'unfolded' attribute may be replaced by first-class proof text.
   221 
   222 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   223 and command 'unfolding' now all support object-level equalities
   224 (potentially conditional).  The underlying notion of rewrite rule is
   225 analogous to the 'rule_format' attribute, but *not* that of the
   226 Simplifier (which is usually more generous).
   227 
   228 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   229 method expression within a sandbox consisting of the first N
   230 sub-goals, which need to exist.  For example, ``simp_all [3]''
   231 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   232 simplifies all new goals that emerge from applying rule foo to the
   233 originally first one.
   234 
   235 * Isar: schematic goals are no longer restricted to higher-order
   236 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   237 expected.
   238 
   239 * Isar: the conclusion of a long theorem statement is now either
   240 'shows' (a simultaneous conjunction, as before), or 'obtains'
   241 (essentially a disjunction of cases with local parameters and
   242 assumptions).  The latter allows to express general elimination rules
   243 adequately; in this notation common elimination rules look like this:
   244 
   245   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   246     assumes "EX x. P x"
   247     obtains x where "P x"
   248 
   249   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   250     assumes "A & B"
   251     obtains A and B
   252 
   253   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   254     assumes "A | B"
   255     obtains
   256       A
   257     | B
   258 
   259 The subsequent classical rules even refer to the formal "thesis"
   260 explicitly:
   261 
   262   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   263     obtains "~ thesis"
   264 
   265   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   266     obtains "thesis ==> something"
   267 
   268 The actual proof of an 'obtains' statement is analogous to that of the
   269 Isar proof element 'obtain', only that there may be several cases.
   270 Optional case names may be specified in parentheses; these will be
   271 available both in the present proof and as annotations in the
   272 resulting rule, for later use with the 'cases' method (cf. attribute
   273 case_names).
   274 
   275 * Isar: the assumptions of a long theorem statement are available as
   276 "assms" fact in the proof context.  This is more appropriate than the
   277 (historical) "prems", which refers to all assumptions of the current
   278 context, including those from the target locale, proof body etc.
   279 
   280 * Isar: 'print_statement' prints theorems from the current theory or
   281 proof context in long statement form, according to the syntax of a
   282 top-level lemma.
   283 
   284 * Isar: 'obtain' takes an optional case name for the local context
   285 introduction rule (default "that").
   286 
   287 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   288 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   289 to occur.
   290 
   291 * Pure: syntax "CONST name" produces a fully internalized constant
   292 according to the current context.  This is particularly useful for
   293 syntax translations that should refer to internal constant
   294 representations independently of name spaces.
   295 
   296 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   297 instead of "FOO ". This allows multiple binder declarations to coexist
   298 in the same context.  INCOMPATIBILITY.
   299 
   300 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   301 primitive that also works in a locale context (both for constants and
   302 fixed variables).  Type declaration and internal syntactic
   303 representation of given constants retrieved from the context.
   304 
   305 * Isar/locales: new derived specification elements 'axiomatization',
   306 'definition', 'abbreviation', which support type-inference, admit
   307 object-level specifications (equality, equivalence).  See also the
   308 isar-ref manual.  Examples:
   309 
   310   axiomatization
   311     eq  (infix "===" 50) where
   312     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   313 
   314   definition "f x y = x + y + 1"
   315   definition g where "g x = f x x"
   316 
   317   abbreviation
   318     neq  (infix "=!=" 50) where
   319     "x =!= y == ~ (x === y)"
   320 
   321 These specifications may be also used in a locale context.  Then the
   322 constants being introduced depend on certain fixed parameters, and the
   323 constant name is qualified by the locale base name.  An internal
   324 abbreviation takes care for convenient input and output, making the
   325 parameters implicit and using the original short name.  See also
   326 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   327 entities from a monomorphic theory.
   328 
   329 Presently, abbreviations are only available 'in' a target locale, but
   330 not inherited by general import expressions.  Also note that
   331 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   332 'translations' in common applications.
   333 
   334 Concrete syntax is attached to specified constants in internal form,
   335 independently of name spaces.  The parse tree representation is
   336 slightly different -- use 'notation' instead of raw 'syntax', and
   337 'translations' with explicit "CONST" markup to accommodate this.
   338 
   339 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   340 the current context.  Print mode "no_abbrevs" prevents inversion of
   341 abbreviations on output.
   342 
   343 * Isar/locales: improved parameter handling:
   344 - use of locales "var" and "struct" no longer necessary;
   345 - parameter renamings are no longer required to be injective.
   346   This enables, for example, to define a locale for endomorphisms thus:
   347   locale endom = homom mult mult h.
   348 
   349 * Isar/locales: changed the way locales with predicates are defined.
   350 Instead of accumulating the specification, the imported expression is
   351 now an interpretation.  INCOMPATIBILITY: different normal form of
   352 locale expressions.  In particular, in interpretations of locales with
   353 predicates, goals repesenting already interpreted fragments are not
   354 removed automatically.  Use methods `intro_locales' and
   355 `unfold_locales'; see below.
   356 
   357 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   358 provide backward reasoning on locales predicates.  The methods are
   359 aware of interpretations and discharge corresponding goals.
   360 `intro_locales' is less aggressive then `unfold_locales' and does not
   361 unfold predicates to assumptions.
   362 
   363 * Isar/locales: the order in which locale fragments are accumulated
   364 has changed.  This enables to override declarations from fragments due
   365 to interpretations -- for example, unwanted simp rules.
   366 
   367 * Isar/locales: interpretation in theories and proof contexts has been
   368 extended.  One may now specify (and prove) equations, which are
   369 unfolded in interpreted theorems.  This is useful for replacing
   370 defined concepts (constants depending on locale parameters) by
   371 concepts already existing in the target context.  Example:
   372 
   373   interpretation partial_order ["op <= :: [int, int] => bool"]
   374     where "partial_order.less (op <=) (x::int) y = (x < y)"
   375 
   376 Typically, the constant `partial_order.less' is created by the
   377 specification element definition in the context of locale partial_order.
   378 
   379 * Provers/induct: improved internal context management to support
   380 local fixes and defines on-the-fly.  Thus explicit meta-level
   381 connectives !! and ==> are rarely required anymore in inductive goals
   382 (using object-logic connectives for this purpose has been long
   383 obsolete anyway).  The subsequent proof patterns illustrate advanced
   384 techniques of natural induction; general datatypes and inductive sets
   385 work analogously (see also src/HOL/Lambda for realistic examples).
   386 
   387 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   388 parameters:
   389 
   390   lemma
   391     fixes n :: nat and x :: 'a
   392     assumes a: "A n x"
   393     shows "P n x"
   394     using a                     -- {* make induct insert fact a *}
   395   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   396     case 0
   397     show ?case sorry
   398   next
   399     case (Suc n)
   400     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   401     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   402     show ?case sorry
   403   qed
   404 
   405 (2) This is how to perform induction over ``expressions of a certain
   406 form'', using a locally defined inductive parameter n == "a x"
   407 together with strengthening (the latter is usually required to get
   408 sufficiently flexible induction hypotheses):
   409 
   410   lemma
   411     fixes a :: "'a => nat"
   412     assumes a: "A (a x)"
   413     shows "P (a x)"
   414     using a
   415   proof (induct n == "a x" arbitrary: x)
   416     ...
   417 
   418 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   419 particular technique.
   420 
   421 (3) This is how to perform existential reasoning ('obtains' or
   422 'obtain') by induction, while avoiding explicit object-logic
   423 encodings:
   424 
   425   lemma
   426     fixes n :: nat
   427     obtains x :: 'a where "P n x" and "Q n x"
   428   proof (induct n arbitrary: thesis)
   429     case 0
   430     obtain x where "P 0 x" and "Q 0 x" sorry
   431     then show thesis by (rule 0)
   432   next
   433     case (Suc n)
   434     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   435     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   436     then show thesis by (rule Suc.prems)
   437   qed
   438 
   439 Here the 'arbitrary: thesis' specification essentially modifies the
   440 scope of the formal thesis parameter, in order to the get the whole
   441 existence statement through the induction as expected.
   442 
   443 * Provers/induct: mutual induction rules are now specified as a list
   444 of rule sharing the same induction cases.  HOL packages usually
   445 provide foo_bar.inducts for mutually defined items foo and bar
   446 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   447 specify mutual induction rules differently, i.e. like this:
   448 
   449   (induct rule: foo_bar.inducts)
   450   (induct set: foo bar)
   451   (induct type: foo bar)
   452 
   453 The ML function ProjectRule.projections turns old-style rules into the
   454 new format.
   455 
   456 * Provers/induct: improved handling of simultaneous goals.  Instead of
   457 introducing object-level conjunction, the statement is now split into
   458 several conclusions, while the corresponding symbolic cases are
   459 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   460 explicitly.  For example:
   461 
   462   lemma
   463     fixes n :: nat
   464     shows "P n" and "Q n"
   465   proof (induct n)
   466     case 0 case 1
   467     show "P 0" sorry
   468   next
   469     case 0 case 2
   470     show "Q 0" sorry
   471   next
   472     case (Suc n) case 1
   473     note `P n` and `Q n`
   474     show "P (Suc n)" sorry
   475   next
   476     case (Suc n) case 2
   477     note `P n` and `Q n`
   478     show "Q (Suc n)" sorry
   479   qed
   480 
   481 The split into subcases may be deferred as follows -- this is
   482 particularly relevant for goal statements with local premises.
   483 
   484   lemma
   485     fixes n :: nat
   486     shows "A n ==> P n" and "B n ==> Q n"
   487   proof (induct n)
   488     case 0
   489     {
   490       case 1
   491       note `A 0`
   492       show "P 0" sorry
   493     next
   494       case 2
   495       note `B 0`
   496       show "Q 0" sorry
   497     }
   498   next
   499     case (Suc n)
   500     note `A n ==> P n` and `B n ==> Q n`
   501     {
   502       case 1
   503       note `A (Suc n)`
   504       show "P (Suc n)" sorry
   505     next
   506       case 2
   507       note `B (Suc n)`
   508       show "Q (Suc n)" sorry
   509     }
   510   qed
   511 
   512 If simultaneous goals are to be used with mutual rules, the statement
   513 needs to be structured carefully as a two-level conjunction, using
   514 lists of propositions separated by 'and':
   515 
   516   lemma
   517     shows "a : A ==> P1 a"
   518           "a : A ==> P2 a"
   519       and "b : B ==> Q1 b"
   520           "b : B ==> Q2 b"
   521           "b : B ==> Q3 b"
   522   proof (induct set: A B)
   523 
   524 * Provers/induct: support coinduction as well.  See
   525 src/HOL/Library/Coinductive_List.thy for various examples.
   526 
   527 * Attribute "symmetric" produces result with standardized schematic
   528 variables (index 0).  Potential INCOMPATIBILITY.
   529 
   530 * Simplifier: by default the simplifier trace only shows top level
   531 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   532 default. Thus there is less danger of being flooded by the trace. The
   533 trace indicates where parts have been suppressed.
   534   
   535 * Provers/classical: removed obsolete classical version of elim_format
   536 attribute; classical elim/dest rules are now treated uniformly when
   537 manipulating the claset.
   538 
   539 * Provers/classical: stricter checks to ensure that supplied intro,
   540 dest and elim rules are well-formed; dest and elim rules must have at
   541 least one premise.
   542 
   543 * Provers/classical: attributes dest/elim/intro take an optional
   544 weight argument for the rule (just as the Pure versions).  Weights are
   545 ignored by automated tools, but determine the search order of single
   546 rule steps.
   547 
   548 * Syntax: input syntax now supports dummy variable binding "%_. b",
   549 where the body does not mention the bound variable.  Note that dummy
   550 patterns implicitly depend on their context of bounds, which makes
   551 "{_. _}" match any set comprehension as expected.  Potential
   552 INCOMPATIBILITY -- parse translations need to cope with syntactic
   553 constant "_idtdummy" in the binding position.
   554 
   555 * Syntax: removed obsolete syntactic constant "_K" and its associated
   556 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   557 for example "A -> B" => "Pi A (%_. B)".
   558 
   559 * Pure: 'class_deps' command visualizes the subclass relation, using
   560 the graph browser tool.
   561 
   562 * Pure: 'print_theory' now suppresses entities with internal name
   563 (trailing "_") by default; use '!' option for full details.
   564 
   565 
   566 *** HOL ***
   567 
   568 * Code generator library theories:
   569   * Pretty_Int represents HOL integers by big integer literals in target
   570     languages.
   571   * Pretty_Char represents HOL characters by character literals in target
   572     languages.
   573   * Pretty_Char_chr like Pretty_Char, but also offers treatment of character
   574     codes; includes Pretty_Int.
   575   * Executable_Set allows to generate code for finite sets using lists.
   576   * Executable_Rat implements rational numbers as triples (sign, enumerator,
   577     denominator).
   578   * Executable_Real implements a subset of real numbers, namly those
   579     representable by rational numbers.
   580   * Efficient_Nat implements natural numbers by integers, which in general will
   581     result in higher efficency; pattern matching with 0/Suc is eliminated;
   582     includes Pretty_Int.
   583   * ML_String provides an additional datatype ml_string; in the HOL default
   584     setup, strings in HOL are mapped to lists of HOL characters in SML; values
   585     of type ml_string are mapped to strings in SML.
   586   * ML_Int provides an additional datatype ml_int which is mapped to to SML
   587     built-in integers.
   588 
   589 * New package for inductive predicates
   590 
   591   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
   592 
   593     inductive
   594       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   595       for z_1 :: U_1 and ... and z_n :: U_m
   596     where
   597       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   598     | ...
   599 
   600   rather than
   601 
   602     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   603 
   604     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   605     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   606 
   607     inductive "s z_1 ... z_m"
   608     intros
   609       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   610       ...
   611 
   612   For backward compatibility, there is a wrapper allowing inductive
   613   sets to be defined with the new package via
   614 
   615     inductive_set
   616       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   617       for z_1 :: U_1 and ... and z_n :: U_m
   618     where
   619       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   620     | ...
   621 
   622   or
   623 
   624     inductive_set
   625       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   626       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   627       for z_1 :: U_1 and ... and z_n :: U_m
   628     where
   629       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   630     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   631     | ...
   632 
   633   if the additional syntax "p ..." is required.
   634 
   635   Many examples can be found in the subdirectories Auth, Bali, Induct,
   636   or MicroJava.
   637 
   638   INCOMPATIBILITIES:
   639 
   640   - Since declaration and definition of inductive sets or predicates
   641     is no longer separated, abbreviations involving the newly introduced
   642     sets or predicates must be specified together with the introduction
   643     rules after the "where" keyword (see example above), rather than before
   644     the actual inductive definition.
   645 
   646   - The variables in induction and elimination rules are now quantified
   647     in the order of their occurrence in the introduction rules, rather than
   648     in alphabetical order. Since this may break some proofs, these proofs
   649     either have to be repaired, e.g. by reordering the variables
   650     a_i_1 ... a_i_{k_i} in Isar "case" statements of the form
   651 
   652       case (rule_i a_i_1 ... a_i_{k_i})
   653 
   654     or the old order of quantification has to be restored by explicitly adding
   655     meta-level quantifiers in the introduction rules, i.e.
   656 
   657       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
   658 
   659   - The format of the elimination rules is now
   660 
   661       p z_1 ... z_m x_1 ... x_n ==>
   662         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   663         ==> ... ==> P
   664 
   665     for predicates and
   666 
   667       (x_1, ..., x_n) : s z_1 ... z_m ==>
   668         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   669         ==> ... ==> P
   670 
   671     for sets rather than
   672 
   673       x : s z_1 ... z_m ==>
   674         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
   675         ==> ... ==> P
   676 
   677     This may require terms in goals to be expanded to n-tuples (e.g. using case_tac
   678     or simplification with the split_paired_all rule) before the above elimination
   679     rule is applicable.
   680 
   681   - The elimination or case analysis rules for (mutually) inductive sets or
   682     predicates are now called "p_1.cases" ... "p_k.cases". The list of rules
   683     "p_1_..._p_k.elims" is no longer available.
   684 
   685 * Method "metis" proves goals by applying the Metis general-purpose
   686 resolution prover.  Examples are in the directory MetisExamples.  See
   687 also http://gilith.com/software/metis/
   688   
   689 * Command 'sledgehammer' invokes external automatic theorem provers as
   690 background processes.  It generates calls to the "metis" method if
   691 successful. These can be pasted into the proof.  Users do not have to
   692 wait for the automatic provers to return.
   693 
   694 * Case-expressions allow arbitrary constructor-patterns (including "_") and
   695   take their order into account, like in functional programming.
   696   Internally, this is translated into nested case-expressions; missing cases
   697   are added and mapped to the predefined constant "undefined". In complicated
   698   cases printing may no longer show the original input but the internal
   699   form. Lambda-abstractions allow the same form of pattern matching:
   700   "% pat1 => e1 | ..." is an abbreviation for
   701   "%x. case x of pat1 => e1 | ..." where x is a new variable.
   702 
   703 * IntDef: The constant "int :: nat => int" has been removed; now "int"
   704   is an abbreviation for "of_nat :: nat => int". The simplification rules
   705   for "of_nat" have been changed to work like "int" did previously.
   706   (potential INCOMPATIBILITY)
   707   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
   708   - of_nat_diff and of_nat_mult are no longer default simp rules
   709 
   710 * Method "algebra" solves polynomial equations over (semi)rings using
   711   Groebner bases. The (semi)ring structure is defined by locales and
   712   the tool setup depends on that generic context. Installing the
   713   method for a specific type involves instantiating the locale and
   714   possibly adding declarations for computation on the coefficients.
   715   The method is already instantiated for natural numbers and for the
   716   axiomatic class of idoms with numerals.  See also the paper by
   717   Chaieb and Wenzel at CALCULEMUS 2007 for the general principles
   718   underlying this architecture of context-aware proof-tools.
   719 
   720 * constant "List.op @" now named "List.append".  Use ML antiquotations
   721 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   722 possible incompatibilities when working on ML level.
   723 
   724 * Constant renames due to introduction of canonical name prefixing for
   725   class package:
   726 
   727     HOL.abs ~> HOL.minus_class.abs
   728     HOL.divide ~> HOL.divide_class.divide
   729     Nat.power ~> Nat.power_class.power
   730     Nat.size ~> Nat.size_class.size
   731     Numeral.number_of ~> Numeral.number_class.number_of
   732     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   733 
   734 * Rudimentary class target mechanism involves constant renames:
   735 
   736     Orderings.min ~> Orderings.ord_class.min
   737     Orderings.max ~> Orderings.ord_class.max
   738     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   739 
   740 * primrec: missing cases mapped to "undefined" instead of "arbitrary"
   741 
   742 * new constant "undefined" with axiom "undefined x = undefined"
   743 
   744 * new class "default" with associated constant "default"
   745 
   746 * new function listsum :: 'a list => 'a for arbitrary monoids.
   747   Special syntax: "SUM x <- xs. f x" (and latex variants)
   748 
   749 * new (input only) syntax for Haskell-like list comprehension, eg
   750   [(x,y). x <- xs, y <- ys, x ~= y]
   751   For details see List.thy.
   752 
   753 * The special syntax for function "filter" has changed from [x : xs. P] to
   754   [x <- xs. P] to avoid an ambiguity caused by list comprehension syntax,
   755   and for uniformity. INCOMPATIBILITY
   756 
   757 * New lemma collection field_simps (an extension of ring_simps)
   758   for manipulating (in)equations involving division. Multiplies
   759   with all denominators that can be proved to be non-zero (in equations)
   760   or positive/negative (in inequations).
   761 
   762 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
   763   have been improved and renamed to ring_simps, group_simps and ring_distribs.
   764   Removed lemmas field_xyz in Ring_and_Field
   765   because they were subsumed by lemmas xyz.
   766 INCOMPATIBILITY.
   767 
   768 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   769   when generating code.
   770 
   771 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   772   when generating code.
   773 
   774 * Library/Commutative_Ring.thy: switched from recdef to function package;
   775   constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   776 
   777 * Some steps towards more uniform lattice theory development in HOL.
   778 
   779     constants "meet" and "join" now named "inf" and "sup"
   780     constant "Meet" now named "Inf"
   781 
   782     classes "meet_semilorder" and "join_semilorder" now named
   783       "lower_semilattice" and "upper_semilattice"
   784     class "lorder" now named "lattice"
   785     class "comp_lat" now named "complete_lattice"
   786 
   787     Instantiation of lattice classes allows explicit definitions
   788     for "inf" and "sup" operations.
   789 
   790   INCOMPATIBILITY.  Theorem renames:
   791 
   792     meet_left_le            ~> inf_le1
   793     meet_right_le           ~> inf_le2
   794     join_left_le            ~> sup_ge1
   795     join_right_le           ~> sup_ge2
   796     meet_join_le            ~> inf_sup_ord
   797     le_meetI                ~> le_infI
   798     join_leI                ~> le_supI
   799     le_meet                 ~> le_inf_iff
   800     le_join                 ~> ge_sup_conv
   801     meet_idempotent         ~> inf_idem
   802     join_idempotent         ~> sup_idem
   803     meet_comm               ~> inf_commute
   804     join_comm               ~> sup_commute
   805     meet_leI1               ~> le_infI1
   806     meet_leI2               ~> le_infI2
   807     le_joinI1               ~> le_supI1
   808     le_joinI2               ~> le_supI2
   809     meet_assoc              ~> inf_assoc
   810     join_assoc              ~> sup_assoc
   811     meet_left_comm          ~> inf_left_commute
   812     meet_left_idempotent    ~> inf_left_idem
   813     join_left_comm          ~> sup_left_commute
   814     join_left_idempotent    ~> sup_left_idem
   815     meet_aci                ~> inf_aci
   816     join_aci                ~> sup_aci
   817     le_def_meet             ~> le_iff_inf
   818     le_def_join             ~> le_iff_sup
   819     join_absorp2            ~> sup_absorb2
   820     join_absorp1            ~> sup_absorb1
   821     meet_absorp1            ~> inf_absorb1
   822     meet_absorp2            ~> inf_absorb2
   823     meet_join_absorp        ~> inf_sup_absorb
   824     join_meet_absorp        ~> sup_inf_absorb
   825     distrib_join_le         ~> distrib_sup_le
   826     distrib_meet_le         ~> distrib_inf_le
   827 
   828     add_meet_distrib_left   ~> add_inf_distrib_left
   829     add_join_distrib_left   ~> add_sup_distrib_left
   830     is_join_neg_meet        ~> is_join_neg_inf
   831     is_meet_neg_join        ~> is_meet_neg_sup
   832     add_meet_distrib_right  ~> add_inf_distrib_right
   833     add_join_distrib_right  ~> add_sup_distrib_right
   834     add_meet_join_distribs  ~> add_sup_inf_distribs
   835     join_eq_neg_meet        ~> sup_eq_neg_inf
   836     meet_eq_neg_join        ~> inf_eq_neg_sup
   837     add_eq_meet_join        ~> add_eq_inf_sup
   838     meet_0_imp_0            ~> inf_0_imp_0
   839     join_0_imp_0            ~> sup_0_imp_0
   840     meet_0_eq_0             ~> inf_0_eq_0
   841     join_0_eq_0             ~> sup_0_eq_0
   842     neg_meet_eq_join        ~> neg_inf_eq_sup
   843     neg_join_eq_meet        ~> neg_sup_eq_inf
   844     join_eq_if              ~> sup_eq_if
   845 
   846     mono_meet               ~> mono_inf
   847     mono_join               ~> mono_sup
   848     meet_bool_eq            ~> inf_bool_eq
   849     join_bool_eq            ~> sup_bool_eq
   850     meet_fun_eq             ~> inf_fun_eq
   851     join_fun_eq             ~> sup_fun_eq
   852     meet_set_eq             ~> inf_set_eq
   853     join_set_eq             ~> sup_set_eq
   854     meet1_iff               ~> inf1_iff
   855     meet2_iff               ~> inf2_iff
   856     meet1I                  ~> inf1I
   857     meet2I                  ~> inf2I
   858     meet1D1                 ~> inf1D1
   859     meet2D1                 ~> inf2D1
   860     meet1D2                 ~> inf1D2
   861     meet2D2                 ~> inf2D2
   862     meet1E                  ~> inf1E
   863     meet2E                  ~> inf2E
   864     join1_iff               ~> sup1_iff
   865     join2_iff               ~> sup2_iff
   866     join1I1                 ~> sup1I1
   867     join2I1                 ~> sup2I1
   868     join1I1                 ~> sup1I1
   869     join2I2                 ~> sup1I2
   870     join1CI                 ~> sup1CI
   871     join2CI                 ~> sup2CI
   872     join1E                  ~> sup1E
   873     join2E                  ~> sup2E
   874 
   875     is_meet_Meet            ~> is_meet_Inf
   876     Meet_bool_def           ~> Inf_bool_def
   877     Meet_fun_def            ~> Inf_fun_def
   878     Meet_greatest           ~> Inf_greatest
   879     Meet_lower              ~> Inf_lower
   880     Meet_set_def            ~> Inf_set_def
   881 
   882     listsp_meetI            ~> listsp_infI
   883     listsp_meet_eq          ~> listsp_inf_eq
   884 
   885     meet_min                ~> inf_min
   886     join_max                ~> sup_max
   887 
   888 * Classes "order" and "linorder": facts "refl", "trans" and
   889 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   890 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   891 
   892 * Classes "order" and "linorder": 
   893 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   894 proofs changed.
   895 
   896 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   897 INCOMPATIBILITY.
   898 
   899 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   900 INCOMPATIBILITY.
   901 
   902 * Added syntactic class "size"; overloaded constant "size" now has
   903 type "'a::size ==> bool"
   904 
   905 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   906 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   907 
   908 * Added method "lexicographic_order" automatically synthesizes
   909 termination relations as lexicographic combinations of size measures
   910 -- 'function' package.
   911 
   912 * HOL/records: generalised field-update to take a function on the
   913 field rather than the new value: r(|A := x|) is translated to A_update
   914 (K x) r The K-combinator that is internally used is called K_record.
   915 INCOMPATIBILITY: Usage of the plain update functions has to be
   916 adapted.
   917  
   918 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   919 0 * x = 0, which are required for a semiring.  Richer structures do
   920 not inherit from semiring_0 anymore, because this property is a
   921 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   922 semiring_0, there is more to prove, but this is mostly trivial.
   923 
   924 * axclass "recpower" was generalized to arbitrary monoids, not just
   925 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   926 commutativity or a semiring property, add the corresponding classes.
   927 
   928 * Unified locale partial_order with class definition (cf. theory
   929 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   930 
   931 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   932 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   933 Isar level, use abbreviations instead.
   934 
   935 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   936 rarely occuring name references (e.g. ``List.op mem.simps'') require
   937 renaming (e.g. ``List.memberl.simps'').
   938 
   939 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   940 INCOMPATIBILITY.
   941 
   942 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
   943 
   944 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   945 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   946 significant changes for setting up numeral syntax for types:
   947 
   948   - new constants Numeral.pred and Numeral.succ instead
   949       of former Numeral.bin_pred and Numeral.bin_succ.
   950   - Use integer operations instead of bin_add, bin_mult and so on.
   951   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   952   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   953 
   954 See HOL/Integ/IntArith.thy for an example setup.
   955 
   956 * New top level command 'normal_form' computes the normal form of a
   957 term that may contain free variables. For example ``normal_form
   958 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   959 suitable for heavy-duty computations because the functions are
   960 compiled to ML first.
   961 
   962 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   963 25 like -->); output depends on the "iff" print_mode, the default is
   964 "A = B" (with priority 50).
   965 
   966 * Renamed constants in HOL.thy and Orderings.thy:
   967     op +   ~> HOL.plus_class.plus
   968     op -   ~> HOL.minus_class.minus
   969     uminus ~> HOL.minus_class.uminus
   970     abs    ~> HOL.abs_class.abs
   971     op *   ~> HOL.times_class.times
   972     op <   ~> HOL.ord_class.less
   973     op <=  ~> HOL.ord_class.less_eq
   974 
   975 Adaptions may be required in the following cases:
   976 
   977 a) User-defined constants using any of the names "plus", "minus", "times",
   978 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   979 may go wrong.
   980 INCOMPATIBILITY: use more specific names.
   981 
   982 b) Variables named "plus", "minus", "times", "less", "less_eq"
   983 INCOMPATIBILITY: use more specific names.
   984 
   985 c) Permutative equations (e.g. "a + b = b + a")
   986 Since the change of names also changes the order of terms, permutative
   987 rewrite rules may get applied in a different order. Experience shows that
   988 this is rarely the case (only two adaptions in the whole Isabelle
   989 distribution).
   990 INCOMPATIBILITY: rewrite proofs
   991 
   992 d) ML code directly refering to constant names
   993 This in general only affects hand-written proof tactics, simprocs and so on.
   994 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   995 of const_name ML antiquotations.
   996 
   997 * Relations less (<) and less_eq (<=) are also available on type bool.
   998 Modified syntax to disallow nesting without explicit parentheses,
   999 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
  1000 
  1001 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1002 
  1003 * Relation composition operator "op O" now has precedence 75 and binds
  1004 stronger than union and intersection. INCOMPATIBILITY.
  1005 
  1006 * The old set interval syntax "{m..n(}" (and relatives) has been
  1007 removed.  Use "{m..<n}" (and relatives) instead.
  1008 
  1009 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1010 "t = s" to False (by simproc "neq_simproc").  For backward
  1011 compatibility this can be disabled by ML "reset use_neq_simproc".
  1012 
  1013 * "m dvd n" where m and n are numbers is evaluated to True/False by
  1014 simp.
  1015 
  1016 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
  1017 
  1018 * Theorem setsum_mult renamed to setsum_right_distrib.
  1019 
  1020 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1021 ``rule'' method.
  1022 
  1023 * Reimplemented methods ``sat'' and ``satx'', with several
  1024 improvements: goals no longer need to be stated as "<prems> ==>
  1025 False", equivalences (i.e. "=" on type bool) are handled, variable
  1026 names of the form "lit_<n>" are no longer reserved, significant
  1027 speedup.
  1028 
  1029 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
  1030 zChaff is still supported as well.
  1031 
  1032 * 'inductive' and 'datatype': provide projections of mutual rules,
  1033 bundled as foo_bar.inducts;
  1034 
  1035 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1036 Library.
  1037 
  1038 * Library: moved theory Accessible_Part to main HOL.
  1039 
  1040 * Library: added theory Coinductive_List of potentially infinite lists
  1041 as greatest fixed-point.
  1042 
  1043 * Library: added theory AssocList which implements (finite) maps as
  1044 association lists.
  1045 
  1046 * Added proof method ``evaluation'' for efficiently solving a goal
  1047 (i.e. a boolean expression) by compiling it to ML. The goal is
  1048 "proved" (via an oracle) if it evaluates to True.
  1049 
  1050 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1051 also when invoked by the simplifier.  This results in the simplifier
  1052 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
  1053 fast_arith_split_limit to 0 to obtain the old behavior.
  1054 
  1055 * Support for hex (0x20) and binary (0b1001) numerals.
  1056 
  1057 * New method: reify eqs (t), where eqs are equations for an
  1058 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1059 parameter, computes a term s::'b and a list xs::'a list and proves the
  1060 theorem I xs s = t. This is also known as reification or quoting. The
  1061 resulting theorem is applied to the subgoal to substitute t with I xs
  1062 s.  If t is omitted, the subgoal itself is reified.
  1063 
  1064 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1065 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1066 where f is supposed to be a computable function (in the sense of code
  1067 generattion). The method uses reify to compute s and xs as above then
  1068 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1069 r and finally gets the theorem t = r, which is again applied to the
  1070 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
  1071 
  1072 * Reflection: Automatic reification now handels binding, an example
  1073 is available in HOL/ex/ReflectionEx.thy
  1074 
  1075 
  1076 *** HOL-Algebra ***
  1077 
  1078 * Formalisation of ideals and the quotient construction over rings.
  1079 
  1080 * Order and lattice theory no longer based on records.
  1081 INCOMPATIBILITY.
  1082 
  1083 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1084 greatest_closed.  INCOMPATIBILITY.
  1085 
  1086 * Method algebra is now set up via an attribute.  For examples see
  1087 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1088 of algebraic structures.
  1089 
  1090 * Renamed theory CRing to Ring.
  1091 
  1092 
  1093 *** HOL-Complex ***
  1094 
  1095 * Theory Real: new method ferrack implements quantifier elimination
  1096 for linear arithmetic over the reals. The quantifier elimination
  1097 feature is used only for decision, for compatibility with arith. This
  1098 means a goal is either solved or left unchanged, no simplification.
  1099 
  1100 * Hyperreal: Functions root and sqrt are now defined on negative real
  1101 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1102 Nonnegativity side conditions have been removed from many lemmas, so
  1103 that more subgoals may now be solved by simplification; potential
  1104 INCOMPATIBILITY.
  1105 
  1106 * Real: New axiomatic classes formalize real normed vector spaces and
  1107 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1108 and norm :: 'a => real.
  1109 
  1110 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
  1111 from reals into other types. The overloaded constant Reals :: 'a set
  1112 is now defined as range of_real; potential INCOMPATIBILITY.
  1113 
  1114 * Real: ML code generation is supported now and hence also quickcheck.
  1115 Reals are implemented as arbitrary precision rationals.
  1116 
  1117 * Hyperreal: Several constants that previously worked only for the
  1118 reals have been generalized, so they now work over arbitrary vector
  1119 spaces. Type annotations may need to be added in some cases; potential
  1120 INCOMPATIBILITY.
  1121 
  1122   Infinitesimal  :: ('a::real_normed_vector) star set
  1123   HFinite        :: ('a::real_normed_vector) star set
  1124   HInfinite      :: ('a::real_normed_vector) star set
  1125   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1126   monad          :: ('a::real_normed_vector) star => 'a star set
  1127   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1128   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1129   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1130   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1131   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1132   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1133   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1134   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1135   sgn            :: 'a::real_normed_vector => 'a
  1136   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1137 
  1138 * Complex: Some complex-specific constants are now abbreviations for
  1139 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1140 hnorm.  Other constants have been entirely removed in favor of the
  1141 polymorphic versions (INCOMPATIBILITY):
  1142 
  1143   approx        <-- capprox
  1144   HFinite       <-- CFinite
  1145   HInfinite     <-- CInfinite
  1146   Infinitesimal <-- CInfinitesimal
  1147   monad         <-- cmonad
  1148   galaxy        <-- cgalaxy
  1149   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1150   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1151   (ns)deriv     <-- (ns)cderiv
  1152 
  1153 
  1154 *** ML ***
  1155 
  1156 * Generic arithmetic modules: Tools/integer.ML, Tools/rat.ML, Tools/float.ML
  1157 
  1158 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1159 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1160 init only required for impure data.  INCOMPATIBILITY: empty really
  1161 need to be empty (no dependencies on theory content!)
  1162 
  1163 * ML within Isar: antiquotations allow to embed statically-checked
  1164 formal entities in the source, referring to the context available at
  1165 compile-time.  For example:
  1166 
  1167 ML {* @{typ "'a => 'b"} *}
  1168 ML {* @{term "%x. x"} *}
  1169 ML {* @{prop "x == y"} *}
  1170 ML {* @{ctyp "'a => 'b"} *}
  1171 ML {* @{cterm "%x. x"} *}
  1172 ML {* @{cprop "x == y"} *}
  1173 ML {* @{thm asm_rl} *}
  1174 ML {* @{thms asm_rl} *}
  1175 ML {* @{const_name c} *}
  1176 ML {* @{const_syntax c} *}
  1177 ML {* @{context} *}
  1178 ML {* @{theory} *}
  1179 ML {* @{theory Pure} *}
  1180 ML {* @{simpset} *}
  1181 ML {* @{claset} *}
  1182 ML {* @{clasimpset} *}
  1183 
  1184 The same works for sources being ``used'' within an Isar context.
  1185 
  1186 * ML in Isar: improved error reporting; extra verbosity with
  1187 Toplevel.debug enabled.
  1188 
  1189 * Pure/library:
  1190 
  1191   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1192   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1193 
  1194 The semantics of "burrow" is: "take a function with *simulatanously*
  1195 transforms a list of value, and apply it *simulatanously* to a list of
  1196 list of values of the appropriate type". Compare this with "map" which
  1197 would *not* apply its argument function simulatanously but in
  1198 sequence; "fold_burrow" has an additional context.
  1199 
  1200 * Pure/library: functions map2 and fold2 with curried syntax for
  1201 simultanous mapping and folding:
  1202 
  1203     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1204     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1205 
  1206 * Pure/library: indexed lists - some functions in the Isabelle library
  1207 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1208 given more convenient names and signatures reminiscent of similar
  1209 functions for alists, tables, etc:
  1210 
  1211   val nth: 'a list -> int -> 'a 
  1212   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1213   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1214 
  1215 Note that fold_index starts counting at index 0, not 1 like foldln
  1216 used to.
  1217 
  1218 * Pure/library: added general ``divide_and_conquer'' combinator on
  1219 lists.
  1220 
  1221 * Pure/General/table.ML: the join operations now works via exceptions
  1222 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1223 admits slightly more efficient complex applications.
  1224 
  1225 * Pure: datatype Context.generic joins theory/Proof.context and
  1226 provides some facilities for code that works in either kind of
  1227 context, notably GenericDataFun for uniform theory and proof data.
  1228 
  1229 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1230 use Context.generic instead of just theory.
  1231 
  1232 * Pure: simplified internal attribute type, which is now always
  1233 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1234 vs. local (Proof.context) attributes have been discontinued, while
  1235 minimizing code duplication.  Thm.rule_attribute and
  1236 Thm.declaration_attribute build canonical attributes; see also
  1237 structure Context for further operations on Context.generic, notably
  1238 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1239 declarations and definitions.
  1240 
  1241 * Pure/kernel: consts certification ignores sort constraints given in
  1242 signature declarations.  (This information is not relevant to the
  1243 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1244 potential INCOMPATIBILITY.
  1245 
  1246 * Pure: axiomatic type classes are now purely definitional, with
  1247 explicit proofs of class axioms and super class relations performed
  1248 internally.  See Pure/axclass.ML for the main internal interfaces --
  1249 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1250 AxClass.axiomatize_class/classrel/arity supercede
  1251 Sign.add_classes/classrel/arities.
  1252 
  1253 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1254 global/local versions on theory vs. Proof.context have been
  1255 discontinued; Attrib.syntax and Method.syntax have been adapted
  1256 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1257 attributes, methods, etc.
  1258 
  1259 * Pure: several functions of signature "... -> theory -> theory * ..."
  1260 have been reoriented to "... -> theory -> ... * theory" in order to
  1261 allow natural usage in combination with the ||>, ||>>, |-> and
  1262 fold_map combinators.
  1263 
  1264 * Pure: official theorem names (closed derivations) and additional
  1265 comments (tags) are now strictly separate.  Name hints -- which are
  1266 maintained as tags -- may be attached any time without affecting the
  1267 derivation.
  1268 
  1269 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1270 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1271 achieve the old behaviour.
  1272 
  1273 * Pure: the "Goal" constant is now called "prop", supporting a
  1274 slightly more general idea of ``protecting'' meta-level rule
  1275 statements.
  1276 
  1277 * Pure: Logic.(un)varify only works in a global context, which is now
  1278 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1279 Logic.legacy_(un)varify as temporary workaround.
  1280 
  1281 * Pure: structure Name provides scalable operations for generating
  1282 internal variable names, notably Name.variants etc.  This replaces
  1283 some popular functions from term.ML:
  1284 
  1285   Term.variant		->  Name.variant
  1286   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1287   Term.invent_names	->  Name.invent_list
  1288 
  1289 Note that low-level renaming rarely occurs in new code -- operations
  1290 from structure Variable are used instead (see below).
  1291 
  1292 * Pure: structure Variable provides fundamental operations for proper
  1293 treatment of fixed/schematic variables in a context.  For example,
  1294 Variable.import introduces fixes for schematics of given facts and
  1295 Variable.export reverses the effect (up to renaming) -- this replaces
  1296 various freeze_thaw operations.
  1297 
  1298 * Pure: structure Goal provides simple interfaces for
  1299 init/conclude/finish and tactical prove operations (replacing former
  1300 Tactic.prove).  Goal.prove is the canonical way to prove results
  1301 within a given context; Goal.prove_global is a degraded version for
  1302 theory level goals, including a global Drule.standard.  Note that
  1303 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1304 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1305 in a locale context).
  1306 
  1307 * Isar: simplified treatment of user-level errors, using exception
  1308 ERROR of string uniformly.  Function error now merely raises ERROR,
  1309 without any side effect on output channels.  The Isar toplevel takes
  1310 care of proper display of ERROR exceptions.  ML code may use plain
  1311 handle/can/try; cat_error may be used to concatenate errors like this:
  1312 
  1313   ... handle ERROR msg => cat_error msg "..."
  1314 
  1315 Toplevel ML code (run directly or through the Isar toplevel) may be
  1316 embedded into the Isar toplevel with exception display/debug like
  1317 this:
  1318 
  1319   Isar.toplevel (fn () => ...)
  1320 
  1321 INCOMPATIBILITY, removed special transform_error facilities, removed
  1322 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1323 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1324 -- use plain ERROR instead.
  1325 
  1326 * Isar: theory setup now has type (theory -> theory), instead of a
  1327 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1328 
  1329 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1330 subject to ProofContext.debug/verbose flags.
  1331 
  1332 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1333 theory before entering a proof state.  Transactions now always see a
  1334 quasi-functional intermediate checkpoint, both in interactive and
  1335 batch mode.
  1336 
  1337 * Simplifier: the simpset of a running simplification process now
  1338 contains a proof context (cf. Simplifier.the_context), which is the
  1339 very context that the initial simpset has been retrieved from (by
  1340 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1341 (solver, looper etc.) may depend on arbitrary proof data.
  1342 
  1343 * Simplifier.inherit_context inherits the proof context (plus the
  1344 local bounds) of the current simplification process; any simproc
  1345 etc. that calls the Simplifier recursively should do this!  Removed
  1346 former Simplifier.inherit_bounds, which is already included here --
  1347 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1348 specify an explicit context using Simplifier.context/theory_context.
  1349 
  1350 * Simplifier/Classical Reasoner: more abstract interfaces
  1351 change_simpset/claset for modifying the simpset/claset reference of a
  1352 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1353 INCOMPATIBILITY.
  1354 
  1355 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1356 "Trueprop" etc.
  1357 
  1358 
  1359 *** System ***
  1360 
  1361 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1362 locations -- now includes the Isabelle version identifier as well.
  1363 This simplifies use of multiple Isabelle installations.
  1364 
  1365 * isabelle-process: option -S (secure mode) disables some critical
  1366 operations, notably runtime compilation and evaluation of ML source
  1367 code.
  1368 
  1369 
  1370 New in Isabelle2005 (October 2005)
  1371 ----------------------------------
  1372 
  1373 *** General ***
  1374 
  1375 * Theory headers: the new header syntax for Isar theories is
  1376 
  1377   theory <name>
  1378   imports <theory1> ... <theoryN>
  1379   uses <file1> ... <fileM>
  1380   begin
  1381 
  1382 where the 'uses' part is optional.  The previous syntax
  1383 
  1384   theory <name> = <theory1> + ... + <theoryN>:
  1385 
  1386 will disappear in the next release.  Use isatool fixheaders to convert
  1387 existing theory files.  Note that there is no change in ancient
  1388 non-Isar theories now, but these will disappear soon.
  1389 
  1390 * Theory loader: parent theories can now also be referred to via
  1391 relative and absolute paths.
  1392 
  1393 * Command 'find_theorems' searches for a list of criteria instead of a
  1394 list of constants. Known criteria are: intro, elim, dest, name:string,
  1395 simp:term, and any term. Criteria can be preceded by '-' to select
  1396 theorems that do not match. Intro, elim, dest select theorems that
  1397 match the current goal, name:s selects theorems whose fully qualified
  1398 name contain s, and simp:term selects all simplification rules whose
  1399 lhs match term.  Any other term is interpreted as pattern and selects
  1400 all theorems matching the pattern. Available in ProofGeneral under
  1401 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1402 
  1403   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1404 
  1405 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1406 matching the current goal as introduction rule and not having "HOL."
  1407 in their name (i.e. not being defined in theory HOL).
  1408 
  1409 * Command 'thms_containing' has been discontinued in favour of
  1410 'find_theorems'; INCOMPATIBILITY.
  1411 
  1412 * Communication with Proof General is now 8bit clean, which means that
  1413 Unicode text in UTF-8 encoding may be used within theory texts (both
  1414 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1415 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1416 
  1417   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1418   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1419 
  1420 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1421 Classical Reasoner.  Typical big applications run around 2 times
  1422 faster.
  1423 
  1424 
  1425 *** Document preparation ***
  1426 
  1427 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1428 of raw sources.  Only those symbols that do not require additional
  1429 LaTeX packages (depending on comments in isabellesym.sty) are
  1430 displayed properly, everything else is left verbatim.  isatool display
  1431 and isatool print are used as front ends (these are subject to the
  1432 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1433 
  1434 * Command tags control specific markup of certain regions of text,
  1435 notably folding and hiding.  Predefined tags include "theory" (for
  1436 theory begin and end), "proof" for proof commands, and "ML" for
  1437 commands involving ML code; the additional tags "visible" and
  1438 "invisible" are unused by default.  Users may give explicit tag
  1439 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1440 interpretation of tags is determined by the LaTeX job during document
  1441 preparation: see option -V of isatool usedir, or options -n and -t of
  1442 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1443 \isadroptag.
  1444 
  1445 Several document versions may be produced at the same time via isatool
  1446 usedir (the generated index.html will link all of them).  Typical
  1447 specifications include ''-V document=theory,proof,ML'' to present
  1448 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1449 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1450 these parts without any formal replacement text.  The Isabelle site
  1451 default settings produce ''document'' and ''outline'' versions as
  1452 specified above.
  1453 
  1454 * Several new antiquotations:
  1455 
  1456   @{term_type term} prints a term with its type annotated;
  1457 
  1458   @{typeof term} prints the type of a term;
  1459 
  1460   @{const const} is the same as @{term const}, but checks that the
  1461   argument is a known logical constant;
  1462 
  1463   @{term_style style term} and @{thm_style style thm} print a term or
  1464   theorem applying a "style" to it
  1465 
  1466   @{ML text}
  1467 
  1468 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1469 definitions, equations, inequations etc., 'concl' printing only the
  1470 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1471 to print the specified premise.  TermStyle.add_style provides an ML
  1472 interface for introducing further styles.  See also the "LaTeX Sugar"
  1473 document practical applications.  The ML antiquotation prints
  1474 type-checked ML expressions verbatim.
  1475 
  1476 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1477 and 'text' support optional locale specification '(in loc)', which
  1478 specifies the default context for interpreting antiquotations.  For
  1479 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1480 
  1481 * Option 'locale=NAME' of antiquotations specifies an alternative
  1482 context interpreting the subsequent argument.  For example: @{thm
  1483 [locale=lattice] inf_assoc}.
  1484 
  1485 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1486 a proof context.
  1487 
  1488 * Proper output of antiquotations for theory commands involving a
  1489 proof context (such as 'locale' or 'theorem (in loc) ...').
  1490 
  1491 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1492 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1493 
  1494 * isatool usedir: new option -C (default true) controls whether option
  1495 -D should include a copy of the original document directory; -C false
  1496 prevents unwanted effects such as copying of administrative CVS data.
  1497 
  1498 
  1499 *** Pure ***
  1500 
  1501 * Considerably improved version of 'constdefs' command.  Now performs
  1502 automatic type-inference of declared constants; additional support for
  1503 local structure declarations (cf. locales and HOL records), see also
  1504 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1505 sequential dependencies of definitions within a single 'constdefs'
  1506 section; moreover, the declared name needs to be an identifier.  If
  1507 all fails, consider to fall back on 'consts' and 'defs' separately.
  1508 
  1509 * Improved indexed syntax and implicit structures.  First of all,
  1510 indexed syntax provides a notational device for subscripted
  1511 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1512 expressions.  Secondly, in a local context with structure
  1513 declarations, number indexes \<^sub>n or the empty index (default
  1514 number 1) refer to a certain fixed variable implicitly; option
  1515 show_structs controls printing of implicit structures.  Typical
  1516 applications of these concepts involve record types and locales.
  1517 
  1518 * New command 'no_syntax' removes grammar declarations (and
  1519 translations) resulting from the given syntax specification, which is
  1520 interpreted in the same manner as for the 'syntax' command.
  1521 
  1522 * 'Advanced' translation functions (parse_translation etc.) may depend
  1523 on the signature of the theory context being presently used for
  1524 parsing/printing, see also isar-ref manual.
  1525 
  1526 * Improved 'oracle' command provides a type-safe interface to turn an
  1527 ML expression of type theory -> T -> term into a primitive rule of
  1528 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1529 is already included here); see also FOL/ex/IffExample.thy;
  1530 INCOMPATIBILITY.
  1531 
  1532 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1533 before); "cI" is no longer bound, use "c.intro" instead.
  1534 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1535 axclasses vs. locales.
  1536 
  1537 * Improved internal renaming of symbolic identifiers -- attach primes
  1538 instead of base 26 numbers.
  1539 
  1540 * New flag show_question_marks controls printing of leading question
  1541 marks in schematic variable names.
  1542 
  1543 * In schematic variable names, *any* symbol following \<^isub> or
  1544 \<^isup> is now treated as part of the base name.  For example, the
  1545 following works without printing of awkward ".0" indexes:
  1546 
  1547   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1548     by simp
  1549 
  1550 * Inner syntax includes (*(*nested*) comments*).
  1551 
  1552 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1553 annotations as "(00...)".
  1554 
  1555 * Clear separation of logical types and nonterminals, where the latter
  1556 may only occur in 'syntax' specifications or type abbreviations.
  1557 Before that distinction was only partially implemented via type class
  1558 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1559 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1560 exotic syntax specifications may require further adaption
  1561 (e.g. Cube/Cube.thy).
  1562 
  1563 * Removed obsolete type class "logic", use the top sort {} instead.
  1564 Note that non-logical types should be declared as 'nonterminals'
  1565 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1566 specifications.
  1567 
  1568 * Attributes 'induct' and 'cases': type or set names may now be
  1569 locally fixed variables as well.
  1570 
  1571 * Simplifier: can now control the depth to which conditional rewriting
  1572 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1573 Limit.
  1574 
  1575 * Simplifier: simplification procedures may now take the current
  1576 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1577 interface), which is very useful for calling the Simplifier
  1578 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1579 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1580 low-level mk_simproc no longer applies Logic.varify internally, to
  1581 allow for use in a context of fixed variables.
  1582 
  1583 * thin_tac now works even if the assumption being deleted contains !!
  1584 or ==>.  More generally, erule now works even if the major premise of
  1585 the elimination rule contains !! or ==>.
  1586 
  1587 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1588 
  1589 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1590 from Pure, which contains all common declarations already.  Both
  1591 theories are defined via plain Isabelle/Isar .thy files.
  1592 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1593 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1594 use isatool fixcpure to adapt your theory and ML sources.
  1595 
  1596 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1597 selections of theorems in named facts via index ranges.
  1598 
  1599 * 'print_theorems': in theory mode, really print the difference
  1600 wrt. the last state (works for interactive theory development only),
  1601 in proof mode print all local facts (cf. 'print_facts');
  1602 
  1603 * 'hide': option '(open)' hides only base names.
  1604 
  1605 * More efficient treatment of intermediate checkpoints in interactive
  1606 theory development.
  1607 
  1608 * Code generator is now invoked via code_module (incremental code
  1609 generation) and code_library (modular code generation, ML structures
  1610 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1611 must be quoted when used as identifiers.
  1612 
  1613 * New 'value' command for reading, evaluating and printing terms using
  1614 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1615 quoted when used as identifier.
  1616 
  1617 
  1618 *** Locales ***
  1619 
  1620 * New commands for the interpretation of locale expressions in
  1621 theories (1), locales (2) and proof contexts (3).  These generate
  1622 proof obligations from the expression specification.  After the
  1623 obligations have been discharged, theorems of the expression are added
  1624 to the theory, target locale or proof context.  The synopsis of the
  1625 commands is a follows:
  1626 
  1627   (1) interpretation expr inst
  1628   (2) interpretation target < expr
  1629   (3) interpret expr inst
  1630 
  1631 Interpretation in theories and proof contexts require a parameter
  1632 instantiation of terms from the current context.  This is applied to
  1633 specifications and theorems of the interpreted expression.
  1634 Interpretation in locales only permits parameter renaming through the
  1635 locale expression.  Interpretation is smart in that interpretations
  1636 that are active already do not occur in proof obligations, neither are
  1637 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1638 inspect active interpretations of a particular locale.  For details,
  1639 see the Isar Reference manual.  Examples can be found in
  1640 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1641 
  1642 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1643 'interpret' instead.
  1644 
  1645 * New context element 'constrains' for adding type constraints to
  1646 parameters.
  1647 
  1648 * Context expressions: renaming of parameters with syntax
  1649 redeclaration.
  1650 
  1651 * Locale declaration: 'includes' disallowed.
  1652 
  1653 * Proper static binding of attribute syntax -- i.e. types / terms /
  1654 facts mentioned as arguments are always those of the locale definition
  1655 context, independently of the context of later invocations.  Moreover,
  1656 locale operations (renaming and type / term instantiation) are applied
  1657 to attribute arguments as expected.
  1658 
  1659 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1660 actual attributes; rare situations may require Attrib.attribute to
  1661 embed those attributes into Attrib.src that lack concrete syntax.
  1662 Attribute implementations need to cooperate properly with the static
  1663 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1664 Attrib.XXX_thm etc. already do the right thing without further
  1665 intervention.  Only unusual applications -- such as "where" or "of"
  1666 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1667 on the context and the facts involved -- may have to assign parsed
  1668 values to argument tokens explicitly.
  1669 
  1670 * Changed parameter management in theorem generation for long goal
  1671 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1672 theorem statement in rare situations.
  1673 
  1674 * Locale inspection command 'print_locale' omits notes elements.  Use
  1675 'print_locale!' to have them included in the output.
  1676 
  1677 
  1678 *** Provers ***
  1679 
  1680 * Provers/hypsubst.ML: improved version of the subst method, for
  1681 single-step rewriting: it now works in bound variable contexts. New is
  1682 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1683 rewrite a different subterm than the original subst method, which is
  1684 still available as 'simplesubst'.
  1685 
  1686 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1687 and quasi orders.
  1688 
  1689 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1690 reflexive-transitive closure of relations.
  1691 
  1692 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1693 limit (previously hard-coded with a value of 20) user-definable.
  1694 
  1695 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1696 is peformed already.  Object-logics merely need to finish their
  1697 initial simpset configuration as before.  INCOMPATIBILITY.
  1698 
  1699 
  1700 *** HOL ***
  1701 
  1702 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1703 
  1704   syntax (epsilon)
  1705     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1706 
  1707 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1708 and x-symbol; use option '-m epsilon' to get it actually printed.
  1709 Moreover, the mathematically important symbolic identifier \<epsilon>
  1710 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1711 
  1712 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1713 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1714 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1715 support corresponding Isar calculations.
  1716 
  1717 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1718 instead of ":".
  1719 
  1720 * theory SetInterval: changed the syntax for open intervals:
  1721 
  1722   Old       New
  1723   {..n(}    {..<n}
  1724   {)n..}    {n<..}
  1725   {m..n(}   {m..<n}
  1726   {)m..n}   {m<..n}
  1727   {)m..n(}  {m<..<n}
  1728 
  1729 The old syntax is still supported but will disappear in the next
  1730 release.  For conversion use the following Emacs search and replace
  1731 patterns (these are not perfect but work quite well):
  1732 
  1733   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1734   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1735 
  1736 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1737 equalities in commutative rings; method 'algebra' provides a generic
  1738 interface.
  1739 
  1740 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1741 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1742 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1743 be a tuple pattern.
  1744 
  1745 Some new syntax forms are available:
  1746 
  1747   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1748   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1749   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1750   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1751 
  1752 The latter form "\<Sum>x < k. e" used to be based on a separate
  1753 function "Summation", which has been discontinued.
  1754 
  1755 * theory Finite_Set: in structured induction proofs, the insert case
  1756 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1757 (insert F x)'.
  1758 
  1759 * The 'refute' command has been extended to support a much larger
  1760 fragment of HOL, including axiomatic type classes, constdefs and
  1761 typedefs, inductive datatypes and recursion.
  1762 
  1763 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1764 Requires zChaff with proof generation to be installed.  See
  1765 HOL/ex/SAT_Examples.thy for examples.
  1766 
  1767 * Datatype induction via method 'induct' now preserves the name of the
  1768 induction variable. For example, when proving P(xs::'a list) by
  1769 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1770 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1771 in unstructured proof scripts.
  1772 
  1773 * Reworked implementation of records.  Improved scalability for
  1774 records with many fields, avoiding performance problems for type
  1775 inference. Records are no longer composed of nested field types, but
  1776 of nested extension types. Therefore the record type only grows linear
  1777 in the number of extensions and not in the number of fields.  The
  1778 top-level (users) view on records is preserved.  Potential
  1779 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1780 old record representation. The type generated for a record is called
  1781 <record_name>_ext_type.
  1782 
  1783 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1784 proofs triggered by a record definition or a simproc (if
  1785 quick_and_dirty is enabled).  Definitions of large records can take
  1786 quite long.
  1787 
  1788 New simproc record_upd_simproc for simplification of multiple record
  1789 updates enabled by default.  Moreover, trivial updates are also
  1790 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1791 occasionally, since simplification is more powerful by default.
  1792 
  1793 * typedef: proper support for polymorphic sets, which contain extra
  1794 type-variables in the term.
  1795 
  1796 * Simplifier: automatically reasons about transitivity chains
  1797 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1798 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1799 old proofs break occasionally as simplification may now solve more
  1800 goals than previously.
  1801 
  1802 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1803 present.  Works for all partial orders (class "order"), in particular
  1804 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1805 just like y <= x.
  1806 
  1807 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1808 bound variable or a constant then the let is unfolded.  Otherwise
  1809 first a is simplified to b, and then f b is simplified to g. If
  1810 possible we abstract b from g arriving at "let x = b in h x",
  1811 otherwise we unfold the let and arrive at g.  The simproc can be
  1812 enabled/disabled by the reference use_let_simproc.  Potential
  1813 INCOMPATIBILITY since simplification is more powerful by default.
  1814 
  1815 * Classical reasoning: the meson method now accepts theorems as arguments.
  1816 
  1817 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1818 jobs to provide advice on the provability of subgoals.
  1819 
  1820 * Theory OrderedGroup and Ring_and_Field: various additions and
  1821 improvements to faciliate calculations involving equalities and
  1822 inequalities.
  1823 
  1824 The following theorems have been eliminated or modified
  1825 (INCOMPATIBILITY):
  1826 
  1827   abs_eq             now named abs_of_nonneg
  1828   abs_of_ge_0        now named abs_of_nonneg
  1829   abs_minus_eq       now named abs_of_nonpos
  1830   imp_abs_id         now named abs_of_nonneg
  1831   imp_abs_neg_id     now named abs_of_nonpos
  1832   mult_pos           now named mult_pos_pos
  1833   mult_pos_le        now named mult_nonneg_nonneg
  1834   mult_pos_neg_le    now named mult_nonneg_nonpos
  1835   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1836   mult_neg           now named mult_neg_neg
  1837   mult_neg_le        now named mult_nonpos_nonpos
  1838 
  1839 * The following lemmas in Ring_and_Field have been added to the simplifier:
  1840      
  1841      zero_le_square
  1842      not_square_less_zero 
  1843 
  1844   The following lemmas have been deleted from Real/RealPow:
  1845   
  1846      realpow_zero_zero
  1847      realpow_two
  1848      realpow_less
  1849      zero_le_power
  1850      realpow_two_le
  1851      abs_realpow_two
  1852      realpow_two_abs     
  1853 
  1854 * Theory Parity: added rules for simplifying exponents.
  1855 
  1856 * Theory List:
  1857 
  1858 The following theorems have been eliminated or modified
  1859 (INCOMPATIBILITY):
  1860 
  1861   list_all_Nil       now named list_all.simps(1)
  1862   list_all_Cons      now named list_all.simps(2)
  1863   list_all_conv      now named list_all_iff
  1864   set_mem_eq         now named mem_iff
  1865 
  1866 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1867 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1868 
  1869 
  1870 *** HOL-Complex ***
  1871 
  1872 * Theory RealDef: better support for embedding natural numbers and
  1873 integers in the reals.
  1874 
  1875 The following theorems have been eliminated or modified
  1876 (INCOMPATIBILITY):
  1877 
  1878   exp_ge_add_one_self  now requires no hypotheses
  1879   real_of_int_add      reversed direction of equality (use [symmetric])
  1880   real_of_int_minus    reversed direction of equality (use [symmetric])
  1881   real_of_int_diff     reversed direction of equality (use [symmetric])
  1882   real_of_int_mult     reversed direction of equality (use [symmetric])
  1883 
  1884 * Theory RComplete: expanded support for floor and ceiling functions.
  1885 
  1886 * Theory Ln is new, with properties of the natural logarithm
  1887 
  1888 * Hyperreal: There is a new type constructor "star" for making
  1889 nonstandard types.  The old type names are now type synonyms:
  1890 
  1891   hypreal = real star
  1892   hypnat = nat star
  1893   hcomplex = complex star
  1894 
  1895 * Hyperreal: Many groups of similarly-defined constants have been
  1896 replaced by polymorphic versions (INCOMPATIBILITY):
  1897 
  1898   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1899 
  1900   starset      <-- starsetNat, starsetC
  1901   *s*          <-- *sNat*, *sc*
  1902   starset_n    <-- starsetNat_n, starsetC_n
  1903   *sn*         <-- *sNatn*, *scn*
  1904   InternalSets <-- InternalNatSets, InternalCSets
  1905 
  1906   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1907   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1908   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1909   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1910   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1911 
  1912 * Hyperreal: Many type-specific theorems have been removed in favor of
  1913 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1914 
  1915   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1916   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1917   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1918   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1919   right_minus <-- hypreal_add_minus
  1920   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1921   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1922   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1923   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1924   mult_1_right <-- hcomplex_mult_one_right
  1925   mult_zero_left <-- hcomplex_mult_zero_left
  1926   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1927   right_distrib <-- hypnat_add_mult_distrib2
  1928   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1929   right_inverse <-- hypreal_mult_inverse
  1930   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1931   order_refl <-- {hypreal,hypnat}_le_refl
  1932   order_trans <-- {hypreal,hypnat}_le_trans
  1933   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1934   order_less_le <-- {hypreal,hypnat}_less_le
  1935   linorder_linear <-- {hypreal,hypnat}_le_linear
  1936   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1937   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1938   add_nonneg_nonneg <-- hypreal_le_add_order
  1939 
  1940 * Hyperreal: Separate theorems having to do with type-specific
  1941 versions of constants have been merged into theorems that apply to the
  1942 new polymorphic constants (INCOMPATIBILITY):
  1943 
  1944   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1945   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1946   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1947   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1948   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1949   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1950   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1951   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1952   STAR_diff <-- {STAR,STARC}_diff
  1953   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1954     STARC_hcomplex_of_complex}_image_subset
  1955   starset_n_Un <-- starset{Nat,C}_n_Un
  1956   starset_n_Int <-- starset{Nat,C}_n_Int
  1957   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1958   starset_n_diff <-- starset{Nat,C}_n_diff
  1959   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1960   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1961   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1962   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1963   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1964   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1965   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1966   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1967   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1968   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1969   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1970   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1971   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1972   starfun_diff <-- starfun{C,RC,CR}_diff
  1973   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1974   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1975   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1976   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1977   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1978   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1979   starfun_Id <-- starfunC_Id
  1980   starfun_approx <-- starfun{Nat,CR}_approx
  1981   starfun_capprox <-- starfun{C,RC}_capprox
  1982   starfun_abs <-- starfunNat_rabs
  1983   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1984   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1985   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1986   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1987   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1988   starfun_add_approx <-- starfunCR_add_approx
  1989   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1990   starfun_divide <-- starfun{C,CR,RC}_divide
  1991   starfun_n <-- starfun{Nat,C}_n
  1992   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1993   starfun_n_add <-- starfun{Nat,C}_n_add
  1994   starfun_n_add_minus <-- starfunNat_n_add_minus
  1995   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1996   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1997   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1998 
  1999   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2000   star_n_minus <-- {hypreal,hcomplex}_minus
  2001   star_n_diff <-- {hypreal,hcomplex}_diff
  2002   star_n_mult <-- {hypreal,hcomplex}_mult
  2003   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2004   star_n_le <-- {hypreal,hypnat}_le
  2005   star_n_less <-- {hypreal,hypnat}_less
  2006   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2007   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2008   star_n_abs <-- hypreal_hrabs
  2009   star_n_divide <-- hcomplex_divide
  2010 
  2011   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2012   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2013   star_of_diff <-- hypreal_of_real_diff
  2014   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2015   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2016   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2017   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2018   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2019   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2020   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2021   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2022   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2023   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2024   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2025   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2026   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2027   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2028   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2029   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2030   star_of_power <-- hypreal_of_real_power
  2031   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2032 
  2033 * Hyperreal: new method "transfer" that implements the transfer
  2034 principle of nonstandard analysis. With a subgoal that mentions
  2035 nonstandard types like "'a star", the command "apply transfer"
  2036 replaces it with an equivalent one that mentions only standard types.
  2037 To be successful, all free variables must have standard types; non-
  2038 standard variables must have explicit universal quantifiers.
  2039 
  2040 * Hyperreal: A theory of Taylor series.
  2041 
  2042 
  2043 *** HOLCF ***
  2044 
  2045 * Discontinued special version of 'constdefs' (which used to support
  2046 continuous functions) in favor of the general Pure one with full
  2047 type-inference.
  2048 
  2049 * New simplification procedure for solving continuity conditions; it
  2050 is much faster on terms with many nested lambda abstractions (cubic
  2051 instead of exponential time).
  2052 
  2053 * New syntax for domain package: selector names are now optional.
  2054 Parentheses should be omitted unless argument is lazy, for example:
  2055 
  2056   domain 'a stream = cons "'a" (lazy "'a stream")
  2057 
  2058 * New command 'fixrec' for defining recursive functions with pattern
  2059 matching; defining multiple functions with mutual recursion is also
  2060 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2061 sinr, or any data constructor defined by the domain package. The given
  2062 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2063 syntax and examples.
  2064 
  2065 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2066 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2067 but the proof obligation additionally includes an admissibility
  2068 requirement. The packages generate instances of class cpo or pcpo,
  2069 with continuity and strictness theorems for Rep and Abs.
  2070 
  2071 * HOLCF: Many theorems have been renamed according to a more standard naming
  2072 scheme (INCOMPATIBILITY):
  2073 
  2074   foo_inject:  "foo$x = foo$y ==> x = y"
  2075   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2076   foo_less:    "(foo$x << foo$y) = (x << y)"
  2077   foo_strict:  "foo$UU = UU"
  2078   foo_defined: "... ==> foo$x ~= UU"
  2079   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2080 
  2081 
  2082 *** ZF ***
  2083 
  2084 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2085 including the First Isomorphism Theorem (on quotienting by the kernel
  2086 of a homomorphism).
  2087 
  2088 * ZF/Simplifier: install second copy of type solver that actually
  2089 makes use of TC rules declared to Isar proof contexts (or locales);
  2090 the old version is still required for ML proof scripts.
  2091 
  2092 
  2093 *** Cube ***
  2094 
  2095 * Converted to Isar theory format; use locales instead of axiomatic
  2096 theories.
  2097 
  2098 
  2099 *** ML ***
  2100 
  2101 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2102 for ||>, ||>>, |>>,
  2103 
  2104 * Pure/library.ML no longer defines its own option datatype, but uses
  2105 that of the SML basis, which has constructors NONE and SOME instead of
  2106 None and Some, as well as exception Option.Option instead of OPTION.
  2107 The functions the, if_none, is_some, is_none have been adapted
  2108 accordingly, while Option.map replaces apsome.
  2109 
  2110 * Pure/library.ML: the exception LIST has been given up in favour of
  2111 the standard exceptions Empty and Subscript, as well as
  2112 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2113 superceded by the standard hd and tl functions etc.
  2114 
  2115 A number of basic list functions are no longer exported to the ML
  2116 toplevel, as they are variants of predefined functions.  The following
  2117 suggests how one can translate existing code:
  2118 
  2119     rev_append xs ys = List.revAppend (xs, ys)
  2120     nth_elem (i, xs) = List.nth (xs, i)
  2121     last_elem xs = List.last xs
  2122     flat xss = List.concat xss
  2123     seq fs = List.app fs
  2124     partition P xs = List.partition P xs
  2125     mapfilter f xs = List.mapPartial f xs
  2126 
  2127 * Pure/library.ML: several combinators for linear functional
  2128 transformations, notably reverse application and composition:
  2129 
  2130   x |> f                f #> g
  2131   (x, y) |-> f          f #-> g
  2132 
  2133 * Pure/library.ML: introduced/changed precedence of infix operators:
  2134 
  2135   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2136   infix 2 ?;
  2137   infix 3 o oo ooo oooo;
  2138   infix 4 ~~ upto downto;
  2139 
  2140 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2141 infix operators.
  2142 
  2143 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2144 fold_map support linear functional transformations and nesting.  For
  2145 example:
  2146 
  2147   fold f [x1, ..., xN] y =
  2148     y |> f x1 |> ... |> f xN
  2149 
  2150   (fold o fold) f [xs1, ..., xsN] y =
  2151     y |> fold f xs1 |> ... |> fold f xsN
  2152 
  2153   fold f [x1, ..., xN] =
  2154     f x1 #> ... #> f xN
  2155 
  2156   (fold o fold) f [xs1, ..., xsN] =
  2157     fold f xs1 #> ... #> fold f xsN
  2158 
  2159 * Pure/library.ML: the following selectors on type 'a option are
  2160 available:
  2161 
  2162   the:               'a option -> 'a  (*partial*)
  2163   these:             'a option -> 'a  where 'a = 'b list
  2164   the_default: 'a -> 'a option -> 'a
  2165   the_list:          'a option -> 'a list
  2166 
  2167 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2168 basic operations for association lists, following natural argument
  2169 order; moreover the explicit equality predicate passed here avoids
  2170 potentially expensive polymorphic runtime equality checks.
  2171 The old functions may be expressed as follows:
  2172 
  2173   assoc = uncurry (AList.lookup (op =))
  2174   assocs = these oo AList.lookup (op =)
  2175   overwrite = uncurry (AList.update (op =)) o swap
  2176 
  2177 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2178 
  2179   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2180   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2181 
  2182 replacing make_keylist and keyfilter (occassionally used)
  2183 Naive rewrites:
  2184 
  2185   make_keylist = AList.make
  2186   keyfilter = AList.find (op =)
  2187 
  2188 * eq_fst and eq_snd now take explicit equality parameter, thus
  2189   avoiding eqtypes. Naive rewrites:
  2190 
  2191     eq_fst = eq_fst (op =)
  2192     eq_snd = eq_snd (op =)
  2193 
  2194 * Removed deprecated apl and apr (rarely used).
  2195   Naive rewrites:
  2196 
  2197     apl (n, op) =>>= curry op n
  2198     apr (op, m) =>>= fn n => op (n, m)
  2199 
  2200 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2201 provides a reasonably efficient light-weight implementation of sets as
  2202 lists.
  2203 
  2204 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2205 few new operations; existing lookup and update are now curried to
  2206 follow natural argument order (for use with fold etc.);
  2207 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2208 
  2209 * Pure/General: output via the Isabelle channels of
  2210 writeln/warning/error etc. is now passed through Output.output, with a
  2211 hook for arbitrary transformations depending on the print_mode
  2212 (cf. Output.add_mode -- the first active mode that provides a output
  2213 function wins).  Already formatted output may be embedded into further
  2214 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2215 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2216 accommodate easy composition of diagnostic messages etc.  Programmers
  2217 rarely need to care about Output.output or Output.raw at all, with
  2218 some notable exceptions: Output.output is required when bypassing the
  2219 standard channels (writeln etc.), or in token translations to produce
  2220 properly formatted results; Output.raw is required when capturing
  2221 already output material that will eventually be presented to the user
  2222 a second time.  For the default print mode, both Output.output and
  2223 Output.raw have no effect.
  2224 
  2225 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2226 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2227 cumulative results are displayed at the end of a batch session.
  2228 
  2229 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2230 replaced by File.platform_path and File.shell_path (with appropriate
  2231 hooks).  This provides a clean interface for unusual systems where the
  2232 internal and external process view of file names are different.
  2233 
  2234 * Pure: more efficient orders for basic syntactic entities: added
  2235 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2236 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2237 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2238 orders now -- potential INCOMPATIBILITY for code that depends on a
  2239 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2240 Library.sort_strings on result).
  2241 
  2242 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2243 fold_types traverse types/terms from left to right, observing natural
  2244 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2245 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2246 
  2247 * Pure: name spaces have been refined, with significant changes of the
  2248 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2249 to extern(_table).  The plain name entry path is superceded by a
  2250 general 'naming' context, which also includes the 'policy' to produce
  2251 a fully qualified name and external accesses of a fully qualified
  2252 name; NameSpace.extend is superceded by context dependent
  2253 Sign.declare_name.  Several theory and proof context operations modify
  2254 the naming context.  Especially note Theory.restore_naming and
  2255 ProofContext.restore_naming to get back to a sane state; note that
  2256 Theory.add_path is no longer sufficient to recover from
  2257 Theory.absolute_path in particular.
  2258 
  2259 * Pure: new flags short_names (default false) and unique_names
  2260 (default true) for controlling output of qualified names.  If
  2261 short_names is set, names are printed unqualified.  If unique_names is
  2262 reset, the name prefix is reduced to the minimum required to achieve
  2263 the original result when interning again, even if there is an overlap
  2264 with earlier declarations.
  2265 
  2266 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2267 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2268 (useful for printing error messages).  INCOMPATIBILITY.
  2269 
  2270 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2271 Theory.theory are now identified, referring to the universal
  2272 Context.theory (see Pure/context.ML).  Actual signature and theory
  2273 content is managed as theory data.  The old code and interfaces were
  2274 spread over many files and structures; the new arrangement introduces
  2275 considerable INCOMPATIBILITY to gain more clarity:
  2276 
  2277   Context -- theory management operations (name, identity, inclusion,
  2278     parents, ancestors, merge, etc.), plus generic theory data;
  2279 
  2280   Sign -- logical signature and syntax operations (declaring consts,
  2281     types, etc.), plus certify/read for common entities;
  2282 
  2283   Theory -- logical theory operations (stating axioms, definitions,
  2284     oracles), plus a copy of logical signature operations (consts,
  2285     types, etc.); also a few basic management operations (Theory.copy,
  2286     Theory.merge, etc.)
  2287 
  2288 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2289 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2290 for convenience -- they merely return the theory.
  2291 
  2292 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2293 
  2294 * Pure: the Isar proof context type is already defined early in Pure
  2295 as Context.proof (note that ProofContext.context and Proof.context are
  2296 aliases, where the latter is the preferred name).  This enables other
  2297 Isabelle components to refer to that type even before Isar is present.
  2298 
  2299 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2300 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2301 any of these kinds.  For example, Sign.intern typeK is now
  2302 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2303 Theory.hide_types.  Also note that former
  2304 Theory.hide_classes/types/consts are now
  2305 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2306 internalize their arguments!  INCOMPATIBILITY.
  2307 
  2308 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2309 datatype thmref (with constructors Name and NameSelection) instead of
  2310 plain string -- INCOMPATIBILITY;
  2311 
  2312 * Pure: cases produced by proof methods specify options, where NONE
  2313 means to remove case bindings -- INCOMPATIBILITY in
  2314 (RAW_)METHOD_CASES.
  2315 
  2316 * Pure: the following operations retrieve axioms or theorems from a
  2317 theory node or theory hierarchy, respectively:
  2318 
  2319   Theory.axioms_of: theory -> (string * term) list
  2320   Theory.all_axioms_of: theory -> (string * term) list
  2321   PureThy.thms_of: theory -> (string * thm) list
  2322   PureThy.all_thms_of: theory -> (string * thm) list
  2323 
  2324 * Pure: print_tac now outputs the goal through the trace channel.
  2325 
  2326 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2327 Reference Toplevel.debug (default false) controls detailed printing
  2328 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2329 controls execution profiling -- set to 1 for time and 2 for space
  2330 (both increase the runtime).
  2331 
  2332 * Isar session: The initial use of ROOT.ML is now always timed,
  2333 i.e. the log will show the actual process times, in contrast to the
  2334 elapsed wall-clock time that the outer shell wrapper produces.
  2335 
  2336 * Simplifier: improved handling of bound variables (nameless
  2337 representation, avoid allocating new strings).  Simprocs that invoke
  2338 the Simplifier recursively should use Simplifier.inherit_bounds to
  2339 avoid local name clashes.  Failure to do so produces warnings
  2340 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2341 for further details.
  2342 
  2343 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2344 bindings for all theorems stored within a given theory; this may help
  2345 in porting non-Isar theories to Isar ones, while keeping ML proof
  2346 scripts for the time being.
  2347 
  2348 * ML operator HTML.with_charset specifies the charset begin used for
  2349 generated HTML files.  For example:
  2350 
  2351   HTML.with_charset "utf-8" use_thy "Hebrew";
  2352   HTML.with_charset "utf-8" use_thy "Chinese";
  2353 
  2354 
  2355 *** System ***
  2356 
  2357 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2358 isabelle, isatool etc.).
  2359 
  2360 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2361 isatool doc, isatool mkdir, display_drafts etc.).
  2362 
  2363 * isatool usedir: option -f allows specification of the ML file to be
  2364 used by Isabelle; default is ROOT.ML.
  2365 
  2366 * New isatool version outputs the version identifier of the Isabelle
  2367 distribution being used.
  2368 
  2369 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2370 (containing Boolean satisfiability problems) into Isabelle/HOL
  2371 theories.
  2372 
  2373 
  2374 
  2375 New in Isabelle2004 (April 2004)
  2376 --------------------------------
  2377 
  2378 *** General ***
  2379 
  2380 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2381   Replaces linorder.ML.
  2382 
  2383 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2384   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2385   (\<a>...\<z>), are now considered normal letters, and can therefore
  2386   be used anywhere where an ASCII letter (a...zA...Z) has until
  2387   now. COMPATIBILITY: This obviously changes the parsing of some
  2388   terms, especially where a symbol has been used as a binder, say
  2389   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2390   as an identifier.  Fix it by inserting a space around former
  2391   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2392   existing theory and ML files.
  2393 
  2394 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2395 
  2396 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2397   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2398   a normal (but invisible) letter. For multiple letter subscripts repeat
  2399   \<^isub> like this: x\<^isub>1\<^isub>2.
  2400 
  2401 * Pure: There are now sub-/superscripts that can span more than one
  2402   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2403   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2404   superscript. The new control characters are not identifier parts.
  2405 
  2406 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2407   content of "..." to the latex file instead of \isacntrl... . The "..."
  2408   may consist of any printable characters excluding the end bracket >.
  2409 
  2410 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2411   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2412   declare constants "final", which prevents their being given a definition
  2413   later.  It is useful for constants whose behaviour is fixed axiomatically
  2414   rather than definitionally, such as the meta-logic connectives.
  2415 
  2416 * Pure: 'instance' now handles general arities with general sorts
  2417   (i.e. intersections of classes),
  2418 
  2419 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2420   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2421   It can be changed to alter the colors/layout of generated pages.
  2422 
  2423 
  2424 *** Isar ***
  2425 
  2426 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2427   cut_tac, subgoal_tac and thin_tac:
  2428   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2429     locales are no longer forced to write Isar proof scripts.
  2430     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2431     emulations.
  2432   - INCOMPATIBILITY: names of variables to be instantiated may no
  2433     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2434     This is consistent with the instantiation attribute "where".
  2435 
  2436 * Attributes "where" and "of":
  2437   - Now take type variables of instantiated theorem into account when reading
  2438     the instantiation string.  This fixes a bug that caused instantiated
  2439     theorems to have too special types in some circumstances.
  2440   - "where" permits explicit instantiations of type variables.
  2441 
  2442 * Calculation commands "moreover" and "also" no longer interfere with
  2443   current facts ("this"), admitting arbitrary combinations with "then"
  2444   and derived forms.
  2445 
  2446 * Locales:
  2447   - Goal statements involving the context element "includes" no longer
  2448     generate theorems with internal delta predicates (those ending on
  2449     "_axioms") in the premise.
  2450     Resolve particular premise with <locale>.intro to obtain old form.
  2451   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2452     specification and "includes" elements in goal statement.
  2453   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2454     [intro?] and [elim?] (respectively) by default.
  2455   - Experimental command for instantiation of locales in proof contexts:
  2456         instantiate <label>[<attrs>]: <loc>
  2457     Instantiates locale <loc> and adds all its theorems to the current context
  2458     taking into account their attributes.  Label and attrs are optional
  2459     modifiers, like in theorem declarations.  If present, names of
  2460     instantiated theorems are qualified with <label>, and the attributes
  2461     <attrs> are applied after any attributes these theorems might have already.
  2462       If the locale has assumptions, a chained fact of the form
  2463     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2464     are derived.  The command does not support old-style locales declared
  2465     with "locale (open)".
  2466       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2467 
  2468 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2469   (Isar) contexts.
  2470 
  2471 
  2472 *** HOL ***
  2473 
  2474 * Proof import: new image HOL4 contains the imported library from
  2475   the HOL4 system with about 2500 theorems. It is imported by
  2476   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2477   can be used like any other Isabelle image.  See
  2478   HOL/Import/HOL/README for more information.
  2479 
  2480 * Simplifier:
  2481   - Much improved handling of linear and partial orders.
  2482     Reasoners for linear and partial orders are set up for type classes
  2483     "linorder" and "order" respectively, and are added to the default simpset
  2484     as solvers.  This means that the simplifier can build transitivity chains
  2485     to solve goals from the assumptions.
  2486   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2487     of blast or auto after simplification become unnecessary because the goal
  2488     is solved by simplification already.
  2489 
  2490 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2491     all proved in axiomatic type classes for semirings, rings and fields.
  2492 
  2493 * Numerics:
  2494   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2495     now formalized using the Ring_and_Field theory mentioned above.
  2496   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2497     than before, because now they are set up once in a generic manner.
  2498   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2499     Look for the general versions in Ring_and_Field (and Power if they concern
  2500     exponentiation).
  2501 
  2502 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2503 
  2504 * Records:
  2505   - Record types are now by default printed with their type abbreviation
  2506     instead of the list of all field types. This can be configured via
  2507     the reference "print_record_type_abbr".
  2508   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2509     (not enabled by default).
  2510   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2511     EX x. x = sel r to True (not enabled by default).
  2512   - Tactic "record_split_simp_tac" to split and simplify records added.
  2513 
  2514 * 'specification' command added, allowing for definition by
  2515   specification.  There is also an 'ax_specification' command that
  2516   introduces the new constants axiomatically.
  2517 
  2518 * arith(_tac) is now able to generate counterexamples for reals as well.
  2519 
  2520 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2521 
  2522 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2523   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2524 
  2525 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2526   matrix theory to linear programming.
  2527 
  2528 * Unions and Intersections:
  2529   The latex output syntax of UN and INT has been changed
  2530   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2531   i.e. the index formulae has become a subscript.
  2532   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2533 
  2534 * Unions and Intersections over Intervals:
  2535   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2536   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2537   like in normal math, and corresponding versions for < and for intersection.
  2538 
  2539 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2540   lexicographic dictonary ordering has been added as "lexord".
  2541 
  2542 * ML: the legacy theory structures Int and List have been removed. They had
  2543   conflicted with ML Basis Library structures having the same names.
  2544 
  2545 * 'refute' command added to search for (finite) countermodels.  Only works
  2546   for a fragment of HOL.  The installation of an external SAT solver is
  2547   highly recommended.  See "HOL/Refute.thy" for details.
  2548 
  2549 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2550   formulae under an assignment of free variables to random values.
  2551   In contrast to 'refute', it can deal with inductive datatypes,
  2552   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2553   for examples.
  2554 
  2555 
  2556 *** HOLCF ***
  2557 
  2558 * Streams now come with concatenation and are part of the HOLCF image
  2559 
  2560 
  2561 
  2562 New in Isabelle2003 (May 2003)
  2563 ------------------------------
  2564 
  2565 *** General ***
  2566 
  2567 * Provers/simplifier:
  2568 
  2569   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2570     Assumptions are now subject to complete mutual simplification,
  2571     not just from left to right. The simplifier now preserves
  2572     the order of assumptions.
  2573 
  2574     Potential INCOMPATIBILITY:
  2575 
  2576     -- simp sometimes diverges where the old version did
  2577        not, e.g. invoking simp on the goal
  2578 
  2579         [| P (f x); y = x; f x = f y |] ==> Q
  2580 
  2581        now gives rise to the infinite reduction sequence
  2582 
  2583         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2584 
  2585        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2586        kind of problem.
  2587 
  2588     -- Tactics combining classical reasoner and simplification (such as auto)
  2589        are also affected by this change, because many of them rely on
  2590        simp. They may sometimes diverge as well or yield a different numbers
  2591        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2592        in case of problems. Sometimes subsequent calls to the classical
  2593        reasoner will fail because a preceeding call to the simplifier too
  2594        eagerly simplified the goal, e.g. deleted redundant premises.
  2595 
  2596   - The simplifier trace now shows the names of the applied rewrite rules
  2597 
  2598   - You can limit the number of recursive invocations of the simplifier
  2599     during conditional rewriting (where the simplifie tries to solve the
  2600     conditions before applying the rewrite rule):
  2601     ML "simp_depth_limit := n"
  2602     where n is an integer. Thus you can force termination where previously
  2603     the simplifier would diverge.
  2604 
  2605   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2606 
  2607   - No longer aborts on failed congruence proof.  Instead, the
  2608     congruence is ignored.
  2609 
  2610 * Pure: New generic framework for extracting programs from constructive
  2611   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2612   as HOL/Extraction for some case studies.
  2613 
  2614 * Pure: The main goal of the proof state is no longer shown by default, only
  2615 the subgoals. This behaviour is controlled by a new flag.
  2616    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2617 (ML: Proof.show_main_goal).
  2618 
  2619 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2620 rules whose conclusion matches subgoal 1:
  2621       PG menu: Isabelle/Isar -> Show me -> matching rules
  2622 The rules are ordered by how closely they match the subgoal.
  2623 In particular, rules that solve a subgoal outright are displayed first
  2624 (or rather last, the way they are printed).
  2625 (ML: ProofGeneral.print_intros())
  2626 
  2627 * Pure: New flag trace_unify_fail causes unification to print
  2628 diagnostic information (PG: in trace buffer) when it fails. This is
  2629 useful for figuring out why single step proofs like rule, erule or
  2630 assumption failed.
  2631 
  2632 * Pure: Locale specifications now produce predicate definitions
  2633 according to the body of text (covering assumptions modulo local
  2634 definitions); predicate "loc_axioms" covers newly introduced text,
  2635 while "loc" is cumulative wrt. all included locale expressions; the
  2636 latter view is presented only on export into the global theory
  2637 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2638 on the old view without predicates;
  2639 
  2640 * Pure: predefined locales "var" and "struct" are useful for sharing
  2641 parameters (as in CASL, for example); just specify something like
  2642 ``var x + var y + struct M'' as import;
  2643 
  2644 * Pure: improved thms_containing: proper indexing of facts instead of
  2645 raw theorems; check validity of results wrt. current name space;
  2646 include local facts of proof configuration (also covers active
  2647 locales), cover fixed variables in index; may use "_" in term
  2648 specification; an optional limit for the number of printed facts may
  2649 be given (the default is 40);
  2650 
  2651 * Pure: disallow duplicate fact bindings within new-style theory files
  2652 (batch-mode only);
  2653 
  2654 * Provers: improved induct method: assumptions introduced by case
  2655 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2656 the goal statement); "foo" still refers to all facts collectively;
  2657 
  2658 * Provers: the function blast.overloaded has been removed: all constants
  2659 are regarded as potentially overloaded, which improves robustness in exchange
  2660 for slight decrease in efficiency;
  2661 
  2662 * Provers/linorder: New generic prover for transitivity reasoning over
  2663 linear orders.  Note: this prover is not efficient!
  2664 
  2665 * Isar: preview of problems to finish 'show' now produce an error
  2666 rather than just a warning (in interactive mode);
  2667 
  2668 
  2669 *** HOL ***
  2670 
  2671 * arith(_tac)
  2672 
  2673  - Produces a counter example if it cannot prove a goal.
  2674    Note that the counter example may be spurious if the goal is not a formula
  2675    of quantifier-free linear arithmetic.
  2676    In ProofGeneral the counter example appears in the trace buffer.
  2677 
  2678  - Knows about div k and mod k where k is a numeral of type nat or int.
  2679 
  2680  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2681    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2682    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2683 
  2684 * simp's arithmetic capabilities have been enhanced a bit: it now
  2685 takes ~= in premises into account (by performing a case split);
  2686 
  2687 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2688 are distributed over a sum of terms;
  2689 
  2690 * New tactic "trans_tac" and method "trans" instantiate
  2691 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2692 "<=", "<" and "=").
  2693 
  2694 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2695 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2696 
  2697 * 'typedef' command has new option "open" to suppress the set
  2698 definition;
  2699 
  2700 * functions Min and Max on finite sets have been introduced (theory
  2701 Finite_Set);
  2702 
  2703 * attribute [symmetric] now works for relations as well; it turns
  2704 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2705 
  2706 * induct over a !!-quantified statement (say !!x1..xn):
  2707   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2708 
  2709 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2710 %x. None. Warning: empty_def now refers to the previously hidden definition
  2711 of the empty set.
  2712 
  2713 * Algebra: formalization of classical algebra.  Intended as base for
  2714 any algebraic development in Isabelle.  Currently covers group theory
  2715 (up to Sylow's theorem) and ring theory (Universal Property of
  2716 Univariate Polynomials).  Contributions welcome;
  2717 
  2718 * GroupTheory: deleted, since its material has been moved to Algebra;
  2719 
  2720 * Complex: new directory of the complex numbers with numeric constants,
  2721 nonstandard complex numbers, and some complex analysis, standard and
  2722 nonstandard (Jacques Fleuriot);
  2723 
  2724 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2725 
  2726 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2727 Fleuriot);
  2728 
  2729 * Real/HahnBanach: updated and adapted to locales;
  2730 
  2731 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2732 Gray and Kramer);
  2733 
  2734 * UNITY: added the Meier-Sanders theory of progress sets;
  2735 
  2736 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2737 as abstract algorithms, instantiated to the JVM;
  2738 
  2739 * Bali: Java source language formalization. Type system, operational
  2740 semantics, axiomatic semantics. Supported language features:
  2741 classes, interfaces, objects,virtual methods, static methods,
  2742 static/instance fields, arrays, access modifiers, definite
  2743 assignment, exceptions.
  2744 
  2745 
  2746 *** ZF ***
  2747 
  2748 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2749 universe, etc.);
  2750 
  2751 * Main ZF: virtually all theories converted to new-style format;
  2752 
  2753 
  2754 *** ML ***
  2755 
  2756 * Pure: Tactic.prove provides sane interface for internal proofs;
  2757 omits the infamous "standard" operation, so this is more appropriate
  2758 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2759 
  2760 * Pure: improved error reporting of simprocs;
  2761 
  2762 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2763 up simprocs;
  2764 
  2765 
  2766 *** Document preparation ***
  2767 
  2768 * uses \par instead of \\ for line breaks in theory text. This may
  2769 shift some page breaks in large documents. To get the old behaviour
  2770 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2771 
  2772 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2773 other packages
  2774 
  2775 * \<euro> now needs package babel/greek instead of marvosym (which
  2776 broke \Rightarrow)
  2777 
  2778 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2779 textcomp package)
  2780 
  2781 
  2782 
  2783 New in Isabelle2002 (March 2002)
  2784 --------------------------------
  2785 
  2786 *** Document preparation ***
  2787 
  2788 * greatly simplified document preparation setup, including more
  2789 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2790 instructive isatool mkdir; users should basically be able to get
  2791 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2792 users may run a separate document processing stage manually like this:
  2793 "isatool usedir -D output HOL Test && isatool document Test/output";
  2794 
  2795 * theory dependency graph may now be incorporated into documents;
  2796 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2797 with \includegraphics of LaTeX;
  2798 
  2799 * proper spacing of consecutive markup elements, especially text
  2800 blocks after section headings;
  2801 
  2802 * support bold style (for single symbols only), input syntax is like
  2803 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2804 
  2805 * \<bullet> is now output as bold \cdot by default, which looks much
  2806 better in printed text;
  2807 
  2808 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2809 note that these symbols are currently unavailable in Proof General /
  2810 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2811 
  2812 * isatool latex no longer depends on changed TEXINPUTS, instead
  2813 isatool document copies the Isabelle style files to the target
  2814 location;
  2815 
  2816 
  2817 *** Isar ***
  2818 
  2819 * Pure/Provers: improved proof by cases and induction;
  2820   - 'case' command admits impromptu naming of parameters (such as
  2821     "case (Suc n)");
  2822   - 'induct' method divinates rule instantiation from the inductive
  2823     claim; no longer requires excessive ?P bindings for proper
  2824     instantiation of cases;
  2825   - 'induct' method properly enumerates all possibilities of set/type
  2826     rules; as a consequence facts may be also passed through *type*
  2827     rules without further ado;
  2828   - 'induct' method now derives symbolic cases from the *rulified*
  2829     rule (before it used to rulify cases stemming from the internal
  2830     atomized version); this means that the context of a non-atomic
  2831     statement becomes is included in the hypothesis, avoiding the
  2832     slightly cumbersome show "PROP ?case" form;
  2833   - 'induct' may now use elim-style induction rules without chaining
  2834     facts, using ``missing'' premises from the goal state; this allows
  2835     rules stemming from inductive sets to be applied in unstructured
  2836     scripts, while still benefitting from proper handling of non-atomic
  2837     statements; NB: major inductive premises need to be put first, all
  2838     the rest of the goal is passed through the induction;
  2839   - 'induct' proper support for mutual induction involving non-atomic
  2840     rule statements (uses the new concept of simultaneous goals, see
  2841     below);
  2842   - append all possible rule selections, but only use the first
  2843     success (no backtracking);
  2844   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2845   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2846   - added 'print_induct_rules' (covered by help item in recent Proof
  2847     General versions);
  2848   - moved induct/cases attributes to Pure, methods to Provers;
  2849   - generic method setup instantiated for FOL and HOL;
  2850 
  2851 * Pure: support multiple simultaneous goal statements, for example
  2852 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2853 meta-level mechanism, this acts as if several individual goals had
  2854 been stated separately; in particular common proof methods need to be
  2855 repeated in order to cover all claims; note that a single elimination
  2856 step is *not* sufficient to establish the two conjunctions, so this
  2857 fails:
  2858 
  2859   assume "A & B" then have A and B ..   (*".." fails*)
  2860 
  2861 better use "obtain" in situations as above; alternative refer to
  2862 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2863 
  2864 * Pure: proper integration with ``locales''; unlike the original
  2865 version by Florian Kammller, Isar locales package high-level proof
  2866 contexts rather than raw logical ones (e.g. we admit to include
  2867 attributes everywhere); operations on locales include merge and
  2868 rename; support for implicit arguments (``structures''); simultaneous
  2869 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2870 some examples;
  2871 
  2872 * Pure: the following commands have been ``localized'', supporting a
  2873 target locale specification "(in name)": 'lemma', 'theorem',
  2874 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2875 stored both within the locale and at the theory level (exported and
  2876 qualified by the locale name);
  2877 
  2878 * Pure: theory goals may now be specified in ``long'' form, with
  2879 ad-hoc contexts consisting of arbitrary locale elements. for example
  2880 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2881 definitions may be given, too); the result is a meta-level rule with
  2882 the context elements being discharged in the obvious way;
  2883 
  2884 * Pure: new proof command 'using' allows to augment currently used
  2885 facts after a goal statement ('using' is syntactically analogous to
  2886 'apply', but acts on the goal's facts only); this allows chained facts
  2887 to be separated into parts given before and after a claim, as in
  2888 ``from a and b have C using d and e <proof>'';
  2889 
  2890 * Pure: renamed "antecedent" case to "rule_context";
  2891 
  2892 * Pure: new 'judgment' command records explicit information about the
  2893 object-logic embedding (used by several tools internally); no longer
  2894 use hard-wired "Trueprop";
  2895 
  2896 * Pure: added 'corollary' command;
  2897 
  2898 * Pure: fixed 'token_translation' command;
  2899 
  2900 * Pure: removed obsolete 'exported' attribute;
  2901 
  2902 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2903 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2904 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2905 
  2906 * Pure: method 'atomize' presents local goal premises as object-level
  2907 statements (atomic meta-level propositions); setup controlled via
  2908 rewrite rules declarations of 'atomize' attribute; example
  2909 application: 'induct' method with proper rule statements in improper
  2910 proof *scripts*;
  2911 
  2912 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2913 now consider the syntactic context of assumptions, giving a better
  2914 chance to get type-inference of the arguments right (this is
  2915 especially important for locales);
  2916 
  2917 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2918 mode;
  2919 
  2920 * Pure/obtain: the formal conclusion "thesis", being marked as
  2921 ``internal'', may no longer be reference directly in the text;
  2922 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2923 situations;
  2924 
  2925 * Pure: generic 'sym' attribute which declares a rule both as pure
  2926 'elim?' and for the 'symmetric' operation;
  2927 
  2928 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2929 text; the fixed correlation with particular command syntax has been
  2930 discontinued;
  2931 
  2932 * Pure: new method 'rules' is particularly well-suited for proof
  2933 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2934 but often produces more compact proof terms with less detours;
  2935 
  2936 * Pure/Provers/classical: simplified integration with pure rule
  2937 attributes and methods; the classical "intro?/elim?/dest?"
  2938 declarations coincide with the pure ones; the "rule" method no longer
  2939 includes classically swapped intros; "intro" and "elim" methods no
  2940 longer pick rules from the context; also got rid of ML declarations
  2941 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2942 INCOMPATIBILITY;
  2943 
  2944 * Provers/classical: attribute 'swapped' produces classical inversions
  2945 of introduction rules;
  2946 
  2947 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2948 rules instead of full simplifier context; 'iff' attribute handles
  2949 conditional rules;
  2950 
  2951 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2952 
  2953 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2954 "(permissive)" option to recover old behavior;
  2955 
  2956 * HOL: 'inductive' no longer features separate (collective) attributes
  2957 for 'intros' (was found too confusing);
  2958 
  2959 * HOL: properly declared induction rules less_induct and
  2960 wf_induct_rule;
  2961 
  2962 
  2963 *** HOL ***
  2964 
  2965 * HOL: moved over to sane numeral syntax; the new policy is as
  2966 follows:
  2967 
  2968   - 0 and 1 are polymorphic constants, which are defined on any
  2969   numeric type (nat, int, real etc.);
  2970 
  2971   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2972   binary representation internally;
  2973 
  2974   - type nat has special constructor Suc, and generally prefers Suc 0
  2975   over 1::nat and Suc (Suc 0) over 2::nat;
  2976 
  2977 This change may cause significant problems of INCOMPATIBILITY; here
  2978 are some hints on converting existing sources:
  2979 
  2980   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2981   entities, so expressions involving "-" (unary or binary minus) need
  2982   to be spaced properly;
  2983 
  2984   - existing occurrences of "1" may need to be constraint "1::nat" or
  2985   even replaced by Suc 0; similar for old "2";
  2986 
  2987   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2988 
  2989   - remove all special provisions on numerals in proofs;
  2990 
  2991 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2992 representation (depends on bin_arith_simps in the default context);
  2993 
  2994 * HOL: symbolic syntax for x^2 (numeral 2);
  2995 
  2996 * HOL: the class of all HOL types is now called "type" rather than
  2997 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2998 in axclass/classes, instance/arities, and (usually rare) occurrences
  2999 in typings (of consts etc.); internally the class is called
  3000 "HOL.type", ML programs should refer to HOLogic.typeS;
  3001 
  3002 * HOL/record package improvements:
  3003   - new derived operations "fields" to build a partial record section,
  3004     "extend" to promote a fixed record to a record scheme, and
  3005     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3006     declared as simp by default;
  3007   - shared operations ("more", "fields", etc.) now need to be always
  3008     qualified) --- potential INCOMPATIBILITY;
  3009   - removed "make_scheme" operations (use "make" with "extend") --
  3010     INCOMPATIBILITY;
  3011   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3012   - provides cases/induct rules for use with corresponding Isar
  3013     methods (for concrete records, record schemes, concrete more
  3014     parts, and schematic more parts -- in that order);
  3015   - internal definitions directly based on a light-weight abstract
  3016     theory of product types over typedef rather than datatype;
  3017 
  3018 * HOL: generic code generator for generating executable ML code from
  3019 specifications; specific support for HOL constructs such as inductive
  3020 datatypes and sets, as well as recursive functions; can be invoked
  3021 via 'generate_code' theory section;
  3022 
  3023 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3024 
  3025 * HOL: consolidated and renamed several theories.  In particular:
  3026         Ord.thy has been absorbed into HOL.thy
  3027         String.thy has been absorbed into List.thy
  3028 
  3029 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3030 (beware of argument permutation!);
  3031 
  3032 * HOL: linorder_less_split superseded by linorder_cases;
  3033 
  3034 * HOL/List: "nodups" renamed to "distinct";
  3035 
  3036 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3037 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3038   - Ex_def has changed, now need to use some_eq_ex
  3039 
  3040 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3041 in this (rare) case use:
  3042 
  3043   delSWrapper "split_all_tac"
  3044   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3045 
  3046 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3047 MAY FAIL;
  3048 
  3049 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3050 Isabelle's type classes, ^ on functions and relations has too general
  3051 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3052 necessary to attach explicit type constraints;
  3053 
  3054 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3055 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3056 renamed accordingly (eg "compI" -> "rel_compI").
  3057 
  3058 * HOL: syntax translations now work properly with numerals and records
  3059 expressions;
  3060 
  3061 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3062 of "lam" -- INCOMPATIBILITY;
  3063 
  3064 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3065 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3066 renamed "Product_Type.unit";
  3067 
  3068 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3069 
  3070 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3071 the "cases" method);
  3072 
  3073 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3074 Florian Kammller);
  3075 
  3076 * HOL/IMP: updated and converted to new-style theory format; several
  3077 parts turned into readable document, with proper Isar proof texts and
  3078 some explanations (by Gerwin Klein);
  3079 
  3080 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3081 
  3082 * HOL-Hyperreal is now a logic image;
  3083 
  3084 
  3085 *** HOLCF ***
  3086 
  3087 * Isar: consts/constdefs supports mixfix syntax for continuous
  3088 operations;
  3089 
  3090 * Isar: domain package adapted to new-style theory format, e.g. see
  3091 HOLCF/ex/Dnat.thy;
  3092 
  3093 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3094 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3095 lift.induct_tac, always use UU instead of Undef;
  3096 
  3097 * HOLCF/IMP: updated and converted to new-style theory;
  3098 
  3099 
  3100 *** ZF ***
  3101 
  3102 * Isar: proper integration of logic-specific tools and packages,
  3103 including theory commands '(co)inductive', '(co)datatype',
  3104 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3105 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3106 
  3107 * theory Main no longer includes AC; for the Axiom of Choice, base
  3108 your theory on Main_ZFC;
  3109 
  3110 * the integer library now covers quotients and remainders, with many
  3111 laws relating division to addition, multiplication, etc.;
  3112 
  3113 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3114 typeless version of the formalism;
  3115 
  3116 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3117 format;
  3118 
  3119 * ZF/Induct: new directory for examples of inductive definitions,
  3120 including theory Multiset for multiset orderings; converted to
  3121 new-style theory format;
  3122 
  3123 * ZF: many new theorems about lists, ordinals, etc.;
  3124 
  3125 
  3126 *** General ***
  3127 
  3128 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3129 variable proof controls level of detail: 0 = no proofs (only oracle
  3130 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3131 also ref manual for further ML interfaces;
  3132 
  3133 * Pure/axclass: removed obsolete ML interface
  3134 goal_subclass/goal_arity;
  3135 
  3136 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3137 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3138 separate tokens, so expressions involving minus need to be spaced
  3139 properly;
  3140 
  3141 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3142 rather than "infixl" or "infixr";
  3143 
  3144 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3145 sort constraint specifications in type inference; e.g. "x::_::foo"
  3146 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3147 type variable);
  3148 
  3149 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3150 control output of nested => (types); the default behavior is
  3151 "type_brackets";
  3152 
  3153 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3154 tokens into AST constants;
  3155 
  3156 * Pure/syntax: prefer later declarations of translations and print
  3157 translation functions; potential INCOMPATIBILITY: need to reverse
  3158 multiple declarations for same syntax element constant;
  3159 
  3160 * Pure/show_hyps reset by default (in accordance to existing Isar
  3161 practice);
  3162 
  3163 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3164 addSafter;
  3165 
  3166 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3167 as well;
  3168 
  3169 * system: tested support for MacOS X; should be able to get Isabelle +
  3170 Proof General to work in a plain Terminal after installing Poly/ML
  3171 (e.g. from the Isabelle distribution area) and GNU bash alone
  3172 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3173 support requires further installations, e.g. from
  3174 http://fink.sourceforge.net/);
  3175 
  3176 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3177 
  3178 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3179 of 40 MB), cf. ML_OPTIONS;
  3180 
  3181 * system: Proof General keywords specification is now part of the
  3182 Isabelle distribution (see etc/isar-keywords.el);
  3183 
  3184 * system: support for persistent Proof General sessions (refrain from
  3185 outdating all loaded theories on startup); user may create writable
  3186 logic images like this: ``isabelle -q HOL Test'';
  3187 
  3188 * system: smart selection of Isabelle process versus Isabelle
  3189 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3190 run both "isabelle" and "Isabelle" even if file names are badly
  3191 damaged (executable inspects the case of the first letter of its own
  3192 name); added separate "isabelle-process" and "isabelle-interface";
  3193 
  3194 * system: refrain from any attempt at filtering input streams; no
  3195 longer support ``8bit'' encoding of old isabelle font, instead proper
  3196 iso-latin characters may now be used; the related isatools
  3197 "symbolinput" and "nonascii" have disappeared as well;
  3198 
  3199 * system: removed old "xterm" interface (the print modes "xterm" and
  3200 "xterm_color" are still available for direct use in a suitable
  3201 terminal);
  3202 
  3203 
  3204 
  3205 New in Isabelle99-2 (February 2001)
  3206 -----------------------------------
  3207 
  3208 *** Overview of INCOMPATIBILITIES ***
  3209 
  3210 * HOL: please note that theories in the Library and elsewhere often use the
  3211 new-style (Isar) format; to refer to their theorems in an ML script you must
  3212 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3213 
  3214 * HOL: inductive package no longer splits induction rule aggressively,
  3215 but only as far as specified by the introductions given; the old
  3216 format may be recovered via ML function complete_split_rule or attribute
  3217 'split_rule (complete)';
  3218 
  3219 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3220 gfp_Tarski to gfp_unfold;
  3221 
  3222 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3223 
  3224 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3225 relation); infix "^^" has been renamed "``"; infix "``" has been
  3226 renamed "`"; "univalent" has been renamed "single_valued";
  3227 
  3228 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3229 operation;
  3230 
  3231 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3232 
  3233 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3234 
  3235 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3236 consequence, it is no longer monotonic wrt. the local goal context
  3237 (which is now passed through the inductive cases);
  3238 
  3239 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3240 \<gg> to \<ggreater>;
  3241 
  3242 
  3243 *** Document preparation ***
  3244 
  3245 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3246 available: are "it" for near math-mode best-style output, "sl" for
  3247 slanted text style, and "tt" for plain type-writer; if no
  3248 \isabellestyle command is given, output is according to slanted
  3249 type-writer);
  3250 
  3251 * support sub/super scripts (for single symbols only), input syntax is
  3252 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3253 
  3254 * some more standard symbols; see Appendix A of the system manual for
  3255 the complete list of symbols defined in isabellesym.sty;
  3256 
  3257 * improved isabelle style files; more abstract symbol implementation
  3258 (should now use \isamath{...} and \isatext{...} in custom symbol
  3259 definitions);
  3260 
  3261 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3262 state; Note that presentation of goal states does not conform to
  3263 actual human-readable proof documents.  Please do not include goal
  3264 states into document output unless you really know what you are doing!
  3265 
  3266 * proper indentation of antiquoted output with proportional LaTeX
  3267 fonts;
  3268 
  3269 * no_document ML operator temporarily disables LaTeX document
  3270 generation;
  3271 
  3272 * isatool unsymbolize tunes sources for plain ASCII communication;
  3273 
  3274 
  3275 *** Isar ***
  3276 
  3277 * Pure: Isar now suffers initial goal statements to contain unbound
  3278 schematic variables (this does not conform to actual readable proof
  3279 documents, due to unpredictable outcome and non-compositional proof
  3280 checking); users who know what they are doing may use schematic goals
  3281 for Prolog-style synthesis of proven results;
  3282 
  3283 * Pure: assumption method (an implicit finishing) now handles actual
  3284 rules as well;
  3285 
  3286 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3287 initial goal, declare "that" only as Pure intro (only for single
  3288 steps); the "that" rule assumption may now be involved in implicit
  3289 finishing, thus ".." becomes a feasible for trivial obtains;
  3290 
  3291 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3292 instance proofs may be performed by "..";
  3293 
  3294 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3295 statements as well;
  3296 
  3297 * Pure: more robust selection of calculational rules;
  3298 
  3299 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3300 rule (as well as the assumption rule);
  3301 
  3302 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3303 lemmas, using the graph browser tool;
  3304 
  3305 * Pure: predict failure of "show" in interactive mode;
  3306 
  3307 * Pure: 'thms_containing' now takes actual terms as arguments;
  3308 
  3309 * HOL: improved method 'induct' --- now handles non-atomic goals
  3310 (potential INCOMPATIBILITY); tuned error handling;
  3311 
  3312 * HOL: cases and induct rules now provide explicit hints about the
  3313 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3314 any remaining facts are inserted into the goal verbatim;
  3315 
  3316 * HOL: local contexts (aka cases) may now contain term bindings as
  3317 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3318 the result to be shown in each case;
  3319 
  3320 * HOL: added 'recdef_tc' command;
  3321 
  3322 * isatool convert assists in eliminating legacy ML scripts;
  3323 
  3324 
  3325 *** HOL ***
  3326 
  3327 * HOL/Library: a collection of generic theories to be used together
  3328 with main HOL; the theory loader path already includes this directory
  3329 by default; the following existing theories have been moved here:
  3330 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3331 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3332 
  3333 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3334 modelling and verification task performed in Isabelle/HOL +
  3335 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3336 
  3337 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3338 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3339 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3340 'domain', this makes the theory consistent with mathematical
  3341 literature;
  3342 
  3343 * HOL basics: added overloaded operations "inverse" and "divide"
  3344 (infix "/"), syntax for generic "abs" operation, generic summation
  3345 operator \<Sum>;
  3346 
  3347 * HOL/typedef: simplified package, provide more useful rules (see also
  3348 HOL/subset.thy);
  3349 
  3350 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3351 now expressed as a proper nested rule (old-style tactic scripts may
  3352 require atomize_strip_tac to cope with non-atomic premises);
  3353 
  3354 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3355 to "split_conv" (old name still available for compatibility);
  3356 
  3357 * HOL: improved concrete syntax for strings (e.g. allows translation
  3358 rules with string literals);
  3359 
  3360 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3361  and Fleuriot's mechanization of analysis, including the transcendental
  3362  functions for the reals;
  3363 
  3364 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3365 
  3366 
  3367 *** CTT ***
  3368 
  3369 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3370 "lam" is displayed as TWO lambda-symbols
  3371 
  3372 * CTT: theory Main now available, containing everything (that is, Bool
  3373 and Arith);
  3374 
  3375 
  3376 *** General ***
  3377 
  3378 * Pure: the Simplifier has been implemented properly as a derived rule
  3379 outside of the actual kernel (at last!); the overall performance
  3380 penalty in practical applications is about 50%, while reliability of
  3381 the Isabelle inference kernel has been greatly improved;
  3382 
  3383 * print modes "brackets" and "no_brackets" control output of nested =>
  3384 (types) and ==> (props); the default behaviour is "brackets";
  3385 
  3386 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3387 as assumptions as well;
  3388 
  3389 * system: support Poly/ML 4.0;
  3390 
  3391 * system: isatool install handles KDE version 1 or 2;
  3392 
  3393 
  3394 
  3395 New in Isabelle99-1 (October 2000)
  3396 ----------------------------------
  3397 
  3398 *** Overview of INCOMPATIBILITIES ***
  3399 
  3400 * HOL: simplification of natural numbers is much changed; to partly
  3401 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3402 issue the following ML commands:
  3403 
  3404   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3405   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3406 
  3407 * HOL: simplification no longer dives into case-expressions; this is
  3408 controlled by "t.weak_case_cong" for each datatype t;
  3409 
  3410 * HOL: nat_less_induct renamed to less_induct;
  3411 
  3412 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3413 fixsome to patch .thy and .ML sources automatically;
  3414 
  3415   select_equality  -> some_equality
  3416   select_eq_Ex     -> some_eq_ex
  3417   selectI2EX       -> someI2_ex
  3418   selectI2         -> someI2
  3419   selectI          -> someI
  3420   select1_equality -> some1_equality
  3421   Eps_sym_eq       -> some_sym_eq_trivial
  3422   Eps_eq           -> some_eq_trivial
  3423 
  3424 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3425 
  3426 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3427 instead);
  3428 
  3429 * HOL: the recursion equations generated by 'recdef' are now called
  3430 f.simps instead of f.rules;
  3431 
  3432 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3433 
  3434 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3435 sometimes be needed;
  3436 
  3437 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3438 
  3439 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3440 
  3441 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3442 product is now "<*>" instead of "Times"; the lexicographic product is
  3443 now "<*lex*>" instead of "**";
  3444 
  3445 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3446 of main HOL, but was unused); better use HOL's datatype package;
  3447 
  3448 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3449 the old syntax may be recovered as follows:
  3450 
  3451   syntax (symbols)
  3452     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3453       (infixl "\\<oplus>" 100)
  3454 
  3455 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3456 
  3457 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3458 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3459 internally;
  3460 
  3461 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3462 changed from A/r to A//r;
  3463 
  3464 * ZF: new treatment of arithmetic (nat & int) may break some old
  3465 proofs;
  3466 
  3467 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3468 rulify -> rule_format, elimify -> elim_format, ...);
  3469 
  3470 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3471 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3472 should have to change intro!! to intro? only); replaced "delrule" by
  3473 "rule del";
  3474 
  3475 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3476 
  3477 * Provers: strengthened force_tac by using new first_best_tac;
  3478 
  3479 * LaTeX document preparation: several changes of isabelle.sty (see
  3480 lib/texinputs);
  3481 
  3482 
  3483 *** Document preparation ***
  3484 
  3485 * formal comments (text blocks etc.) in new-style theories may now
  3486 contain antiquotations of thm/prop/term/typ/text to be presented
  3487 according to latex print mode; concrete syntax is like this:
  3488 @{term[show_types] "f(x) = a + x"};
  3489 
  3490 * isatool mkdir provides easy setup of Isabelle session directories,
  3491 including proper document sources;
  3492 
  3493 * generated LaTeX sources are now deleted after successful run
  3494 (isatool document -c); may retain a copy somewhere else via -D option
  3495 of isatool usedir;
  3496 
  3497 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3498 style files, achieving self-contained LaTeX sources and simplifying
  3499 LaTeX debugging;
  3500 
  3501 * old-style theories now produce (crude) LaTeX output as well;
  3502 
  3503 * browser info session directories are now self-contained (may be put
  3504 on WWW server seperately); improved graphs of nested sessions; removed
  3505 graph for 'all sessions';
  3506 
  3507 * several improvements in isabelle style files; \isabellestyle{it}
  3508 produces fake math mode output; \isamarkupheader is now \section by
  3509 default; see lib/texinputs/isabelle.sty etc.;
  3510 
  3511 
  3512 *** Isar ***
  3513 
  3514 * Isar/Pure: local results and corresponding term bindings are now
  3515 subject to Hindley-Milner polymorphism (similar to ML); this
  3516 accommodates incremental type-inference very nicely;
  3517 
  3518 * Isar/Pure: new derived language element 'obtain' supports
  3519 generalized existence reasoning;
  3520 
  3521 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3522 support accumulation of results, without applying any rules yet;
  3523 useful to collect intermediate results without explicit name
  3524 references, and for use with transitivity rules with more than 2
  3525 premises;
  3526 
  3527 * Isar/Pure: scalable support for case-analysis type proofs: new
  3528 'case' language element refers to local contexts symbolically, as
  3529 produced by certain proof methods; internally, case names are attached
  3530 to theorems as "tags";
  3531 
  3532 * Isar/Pure: theory command 'hide' removes declarations from
  3533 class/type/const name spaces;
  3534 
  3535 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3536 indicate potential overloading;
  3537 
  3538 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3539 
  3540 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3541 "{a,b,c}" instead of {a,b,c};
  3542 
  3543 * Isar/Pure now provides its own version of intro/elim/dest
  3544 attributes; useful for building new logics, but beware of confusion
  3545 with the version in Provers/classical;
  3546 
  3547 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3548 case name 'antecedent';
  3549 
  3550 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3551 to the current context is now done automatically);
  3552 
  3553 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3554 for definining proof methods in ML;
  3555 
  3556 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3557 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3558 most cases, one should have to change intro!! to intro? only);
  3559 replaced "delrule" by "rule del";
  3560 
  3561 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3562 'symmetric' attribute (the latter supercedes [RS sym]);
  3563 
  3564 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3565 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3566 well (including splits);
  3567 
  3568 * Isar/Provers: Simplifier and Classical methods now support all kind
  3569 of modifiers used in the past, including 'cong', 'iff', etc.
  3570 
  3571 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3572 of Simplifier and Classical reasoner);
  3573 
  3574 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3575 now support named cases; major packages (inductive, datatype, primrec,
  3576 recdef) support case names and properly name parameters;
  3577 
  3578 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3579 monotonicity conditions are extracted to be proven at end of
  3580 calculations;
  3581 
  3582 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3583 method anyway;
  3584 
  3585 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3586 split_if split_if_asm; datatype package provides theorems foo.splits =
  3587 foo.split foo.split_asm for each datatype;
  3588 
  3589 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3590 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3591 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3592 use "(cases (simplified))" method in proper proof texts);
  3593 
  3594 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3595 
  3596 * Isar: names of theorems etc. may be natural numbers as well;
  3597 
  3598 * Isar: 'pr' command: optional arguments for goals_limit and
  3599 ProofContext.prems_limit; no longer prints theory contexts, but only
  3600 proof states;
  3601 
  3602 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3603 additional print modes to be specified; e.g. "pr(latex)" will print
  3604 proof state according to the Isabelle LaTeX style;
  3605 
  3606 * Isar: improved support for emulating tactic scripts, including proof
  3607 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3608 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3609 (for HOL datatypes);
  3610 
  3611 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3612 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3613 'proof method scripts' have to be in depth-first order;
  3614 
  3615 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3616 
  3617 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3618 should instead use individual commands for printing items
  3619 (print_commands, print_methods etc.);
  3620 
  3621 * Isar: added 'nothing' --- the empty list of theorems;
  3622 
  3623 
  3624 *** HOL ***
  3625 
  3626 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3627 corresponding virtual machine and a specification of its bytecode
  3628 verifier and a lightweight bytecode verifier, including proofs of
  3629 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3630 Cornelia Pusch (see also the homepage of project Bali at
  3631 http://isabelle.in.tum.de/Bali/);
  3632 
  3633 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3634 Clemens Ballarin;
  3635 
  3636 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3637 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3638 Rasmussen;
  3639 
  3640 * HOL/Lattice: fundamental concepts of lattice theory and order
  3641 structures, including duals, properties of bounds versus algebraic
  3642 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3643 Theorem for complete lattices etc.; may also serve as a demonstration
  3644 for abstract algebraic reasoning using axiomatic type classes, and
  3645 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3646 
  3647 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3648 von Oheimb;
  3649 
  3650 * HOL/IMPP: extension of IMP with local variables and mutually
  3651 recursive procedures, by David von Oheimb;
  3652 
  3653 * HOL/Lambda: converted into new-style theory and document;
  3654 
  3655 * HOL/ex/Multiquote: example of multiple nested quotations and
  3656 anti-quotations -- basically a generalized version of de-Bruijn
  3657 representation; very useful in avoiding lifting of operations;
  3658 
  3659 * HOL/record: added general record equality rule to simpset; fixed
  3660 select-update simplification procedure to handle extended records as
  3661 well; admit "r" as field name;
  3662 
  3663 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3664 other numeric types and also as the identity of groups, rings, etc.;
  3665 
  3666 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3667 Types nat and int belong to this axclass;
  3668 
  3669 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3670    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3671    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3672   two terms #m*u and #n*u are replaced by #(m+n)*u
  3673     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3674   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3675     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3676 
  3677 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3678 powerful prover for predicate logic but knows nothing of clasets; see
  3679 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3680 
  3681 * HOL: new version of "case_tac" subsumes both boolean case split and
  3682 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3683 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3684 
  3685 * HOL: simplification no longer dives into case-expressions: only the
  3686 selector expression is simplified, but not the remaining arms; to
  3687 enable full simplification of case-expressions for datatype t, you may
  3688 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3689 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3690 
  3691 * HOL/recdef: the recursion equations generated by 'recdef' for
  3692 function 'f' are now called f.simps instead of f.rules; if all
  3693 termination conditions are proved automatically, these simplification
  3694 rules are added to the simpset, as in primrec; rules may be named
  3695 individually as well, resulting in a separate list of theorems for
  3696 each equation;
  3697 
  3698 * HOL/While is a new theory that provides a while-combinator. It
  3699 permits the definition of tail-recursive functions without the
  3700 provision of a termination measure. The latter is necessary once the
  3701 invariant proof rule for while is applied.
  3702 
  3703 * HOL: new (overloaded) notation for the set of elements below/above
  3704 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3705 
  3706 * HOL: theorems impI, allI, ballI bound as "strip";
  3707 
  3708 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3709 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3710 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3711 
  3712 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3713 
  3714 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3715 main HOL, but was unused);
  3716 
  3717 * HOL: fewer consts declared as global (e.g. have to refer to
  3718 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3719 
  3720 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3721 in case of overlap with user translations (e.g. judgements over
  3722 tuples); (note that the underlying logical represenation is still
  3723 bogus);
  3724 
  3725 
  3726 *** ZF ***
  3727 
  3728 * ZF: simplification automatically cancels common terms in arithmetic
  3729 expressions over nat and int;
  3730 
  3731 * ZF: new treatment of nat to minimize type-checking: all operators
  3732 coerce their operands to a natural number using the function natify,
  3733 making the algebraic laws unconditional;
  3734 
  3735 * ZF: as above, for int: operators coerce their operands to an integer
  3736 using the function intify;
  3737 
  3738 * ZF: the integer library now contains many of the usual laws for the
  3739 orderings, including $<=, and monotonicity laws for $+ and $*;
  3740 
  3741 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3742 simplification;
  3743 
  3744 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3745 to the simplifier and classical reasoner simultaneously;
  3746 
  3747 
  3748 *** General ***
  3749 
  3750 * Provers: blast_tac now handles actual object-logic rules as
  3751 assumptions; note that auto_tac uses blast_tac internally as well;
  3752 
  3753 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3754 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3755 
  3756 * Provers: delrules now handles destruct rules as well (no longer need
  3757 explicit make_elim);
  3758 
  3759 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3760   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3761 use instead the strong form,
  3762   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3763 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3764 from destruct-rules;
  3765 
  3766 * Provers: Simplifier.easy_setup provides a fast path to basic
  3767 Simplifier setup for new object-logics;
  3768 
  3769 * Pure: AST translation rules no longer require constant head on LHS;
  3770 
  3771 * Pure: improved name spaces: ambiguous output is qualified; support
  3772 for hiding of names;
  3773 
  3774 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3775 XSYMBOL_HOME; no longer need to do manual configuration in most
  3776 situations;
  3777 
  3778 * system: compression of ML heaps images may now be controlled via -c
  3779 option of isabelle and isatool usedir (currently only observed by
  3780 Poly/ML);
  3781 
  3782 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3783 useful for remote X11);
  3784 
  3785 * system: provide TAGS file for Isabelle sources;
  3786 
  3787 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3788 order;
  3789 
  3790 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3791 timing flag supersedes proof_timing and Toplevel.trace;
  3792 
  3793 * ML: new combinators |>> and |>>> for incremental transformations
  3794 with secondary results (e.g. certain theory extensions):
  3795 
  3796 * ML: PureThy.add_defs gets additional argument to indicate potential
  3797 overloading (usually false);
  3798 
  3799 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3800 results;
  3801 
  3802 
  3803 
  3804 New in Isabelle99 (October 1999)
  3805 --------------------------------
  3806 
  3807 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3808 
  3809 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3810 are no longer simplified.  (This allows the simplifier to unfold recursive
  3811 functional programs.)  To restore the old behaviour, declare
  3812 
  3813     Delcongs [if_weak_cong];
  3814 
  3815 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3816 complement;
  3817 
  3818 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3819 
  3820 * HOL/datatype: mutual_induct_tac no longer exists --
  3821   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3822 
  3823 * HOL/typedef: fixed type inference for representing set; type
  3824 arguments now have to occur explicitly on the rhs as type constraints;
  3825 
  3826 * ZF: The con_defs part of an inductive definition may no longer refer
  3827 to constants declared in the same theory;
  3828 
  3829 * HOL, ZF: the function mk_cases, generated by the inductive
  3830 definition package, has lost an argument.  To simplify its result, it
  3831 uses the default simpset instead of a supplied list of theorems.
  3832 
  3833 * HOL/List: the constructors of type list are now Nil and Cons;
  3834 
  3835 * Simplifier: the type of the infix ML functions
  3836         setSSolver addSSolver setSolver addSolver
  3837 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3838 for packaging solvers. A solver is created via
  3839         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3840 where the string argument is only a comment.
  3841 
  3842 
  3843 *** Proof tools ***
  3844 
  3845 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3846 decision procedure for linear arithmetic. Currently it is used for
  3847 types `nat', `int', and `real' in HOL (see below); it can, should and
  3848 will be instantiated for other types and logics as well.
  3849 
  3850 * The simplifier now accepts rewrite rules with flexible heads, eg
  3851      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3852   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3853   matching.
  3854 
  3855 
  3856 *** General ***
  3857 
  3858 * New Isabelle/Isar subsystem provides an alternative to traditional
  3859 tactical theorem proving; together with the ProofGeneral/isar user
  3860 interface it offers an interactive environment for developing human
  3861 readable proof documents (Isar == Intelligible semi-automated
  3862 reasoning); for further information see isatool doc isar-ref,
  3863 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3864 
  3865 * improved and simplified presentation of theories: better HTML markup
  3866 (including colors), graph views in several sizes; isatool usedir now
  3867 provides a proper interface for user theories (via -P option); actual
  3868 document preparation based on (PDF)LaTeX is available as well (for
  3869 new-style theories only); see isatool doc system for more information;
  3870 
  3871 * native support for Proof General, both for classic Isabelle and
  3872 Isabelle/Isar;
  3873 
  3874 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3875 using the graph browser tool;
  3876 
  3877 * Isabelle manuals now also available as PDF;
  3878 
  3879 * theory loader rewritten from scratch (may not be fully
  3880 bug-compatible); old loadpath variable has been replaced by show_path,
  3881 add_path, del_path, reset_path functions; new operations such as
  3882 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3883 isatool doc ref);
  3884 
  3885 * improved isatool install: option -k creates KDE application icon,
  3886 option -p DIR installs standalone binaries;
  3887 
  3888 * added ML_PLATFORM setting (useful for cross-platform installations);
  3889 more robust handling of platform specific ML images for SML/NJ;
  3890 
  3891 * the settings environment is now statically scoped, i.e. it is never
  3892 created again in sub-processes invoked from isabelle, isatool, or
  3893 Isabelle;
  3894 
  3895 * path element specification '~~' refers to '$ISABELLE_HOME';
  3896 
  3897 * in locales, the "assumes" and "defines" parts may be omitted if
  3898 empty;
  3899 
  3900 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3901 long arrows);
  3902 
  3903 * new print_mode "HTML";
  3904 
  3905 * new flag show_tags controls display of tags of theorems (which are
  3906 basically just comments that may be attached by some tools);
  3907 
  3908 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3909 mode and goal output format:
  3910 
  3911 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3912 244c244
  3913 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3914 ---
  3915 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3916 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3917 181c181
  3918 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3919 ---
  3920 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3921 
  3922 * function bind_thms stores lists of theorems (cf. bind_thm);
  3923 
  3924 * new shorthand tactics ftac, eatac, datac, fatac;
  3925 
  3926 * qed (and friends) now accept "" as result name; in that case the
  3927 theorem is not stored, but proper checks and presentation of the
  3928 result still apply;
  3929 
  3930 * theorem database now also indexes constants "Trueprop", "all",
  3931 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3932 
  3933 
  3934 *** HOL ***
  3935 
  3936 ** HOL arithmetic **
  3937 
  3938 * There are now decision procedures for linear arithmetic over nat and
  3939 int:
  3940 
  3941 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3942 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3943 are treated as atomic; subformulae not involving type `nat' or `int'
  3944 are ignored; quantified subformulae are ignored unless they are
  3945 positive universal or negative existential. The tactic has to be
  3946 invoked by hand and can be a little bit slow. In particular, the
  3947 running time is exponential in the number of occurrences of `min' and
  3948 `max', and `-' on `nat'.
  3949 
  3950 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3951 (negated) (in)equalities among the premises and the conclusion into
  3952 account (i.e. no compound formulae) and does not know about `min' and
  3953 `max', and `-' on `nat'. It is fast and is used automatically by the
  3954 simplifier.
  3955 
  3956 NB: At the moment, these decision procedures do not cope with mixed
  3957 nat/int formulae where the two parts interact, such as `m < n ==>
  3958 int(m) < int(n)'.
  3959 
  3960 * HOL/Numeral provides a generic theory of numerals (encoded
  3961 efficiently as bit strings); setup for types nat/int/real is in place;
  3962 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3963 int, existing theories and proof scripts may require a few additional
  3964 type constraints;
  3965 
  3966 * integer division and remainder can now be performed on constant
  3967 arguments;
  3968 
  3969 * many properties of integer multiplication, division and remainder
  3970 are now available;
  3971 
  3972 * An interface to the Stanford Validity Checker (SVC) is available through the
  3973 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3974 are proved automatically.  SVC must be installed separately, and its results
  3975 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3976 invocation of the underlying oracle).  For SVC see
  3977   http://verify.stanford.edu/SVC
  3978 
  3979 * IsaMakefile: the HOL-Real target now builds an actual image;
  3980 
  3981 
  3982 ** HOL misc **
  3983 
  3984 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3985 (in Isabelle/Isar) -- by Gertrud Bauer;
  3986 
  3987 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3988 analysis for assembly languages with subtypes;
  3989 
  3990 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3991 -- avoids syntactic ambiguities and treats state, transition, and
  3992 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3993 changed syntax and (many) tactics;
  3994 
  3995 * HOL/inductive: Now also handles more general introduction rules such
  3996   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3997   theorems are now maintained within the theory (maintained via the
  3998   "mono" attribute);
  3999 
  4000 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4001   (using function types) such as
  4002 
  4003   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4004 
  4005 * HOL/record: record_simproc (part of the default simpset) takes care
  4006 of selectors applied to updated records; record_split_tac is no longer
  4007 part of the default claset; update_defs may now be removed from the
  4008 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4009 
  4010   claset_ref () := claset() addSWrapper record_split_wrapper;
  4011   Delsimprocs [record_simproc]
  4012 
  4013 * HOL/typedef: fixed type inference for representing set; type
  4014 arguments now have to occur explicitly on the rhs as type constraints;
  4015 
  4016 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4017 names rather than an ML expression;
  4018 
  4019 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4020 supplied later.  Program schemes can be defined, such as
  4021     "While B C s = (if B s then While B C (C s) else s)"
  4022 where the well-founded relation can be chosen after B and C have been given.
  4023 
  4024 * HOL/List: the constructors of type list are now Nil and Cons;
  4025 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4026 course, ML tools referring to List.list.op # etc. have to be adapted;
  4027 
  4028 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4029 disabled by default; run isabelle with option -m HOL to get back to
  4030 the original Gordon/HOL-style output;
  4031 
  4032 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4033 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4034 
  4035 * HOL basic syntax simplified (more orthogonal): all variants of
  4036 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4037 Eps operator is provided as well: "SOME x. P[x]";
  4038 
  4039 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4040 
  4041 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4042 thus available for user theories;
  4043 
  4044 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4045 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4046 time;
  4047 
  4048 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4049 several times and then mp;
  4050 
  4051 
  4052 *** LK ***
  4053 
  4054 * the notation <<...>> is now available as a notation for sequences of
  4055 formulas;
  4056 
  4057 * the simplifier is now installed
  4058 
  4059 * the axiom system has been generalized (thanks to Soren Heilmann)
  4060 
  4061 * the classical reasoner now has a default rule database
  4062 
  4063 
  4064 *** ZF ***
  4065 
  4066 * new primrec section allows primitive recursive functions to be given
  4067 directly (as in HOL) over datatypes and the natural numbers;
  4068 
  4069 * new tactics induct_tac and exhaust_tac for induction (or case
  4070 analysis) over datatypes and the natural numbers;
  4071 
  4072 * the datatype declaration of type T now defines the recursor T_rec;
  4073 
  4074 * simplification automatically does freeness reasoning for datatype
  4075 constructors;
  4076 
  4077 * automatic type-inference, with AddTCs command to insert new
  4078 type-checking rules;
  4079 
  4080 * datatype introduction rules are now added as Safe Introduction rules
  4081 to the claset;
  4082 
  4083 * the syntax "if P then x else y" is now available in addition to
  4084 if(P,x,y);
  4085 
  4086 
  4087 *** Internal programming interfaces ***
  4088 
  4089 * tuned simplifier trace output; new flag debug_simp;
  4090 
  4091 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4092 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4093 
  4094 * AxClass.axclass_tac lost the theory argument;
  4095 
  4096 * tuned current_goals_markers semantics: begin / end goal avoids
  4097 printing empty lines;
  4098 
  4099 * removed prs and prs_fn hook, which was broken because it did not
  4100 include \n in its semantics, forcing writeln to add one
  4101 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4102 string -> unit if you really want to output text without newline;
  4103 
  4104 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4105 plain output, interface builders may have to enable 'isabelle_font'
  4106 mode to get Isabelle font glyphs as before;
  4107 
  4108 * refined token_translation interface; INCOMPATIBILITY: output length
  4109 now of type real instead of int;
  4110 
  4111 * theory loader actions may be traced via new ThyInfo.add_hook
  4112 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4113 your own database of information attached to *whole* theories -- as
  4114 opposed to intra-theory data slots offered via TheoryDataFun;
  4115 
  4116 * proper handling of dangling sort hypotheses (at last!);
  4117 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4118 extra sort hypotheses that can be witnessed from the type signature;
  4119 the force_strip_shyps flag is gone, any remaining shyps are simply
  4120 left in the theorem (with a warning issued by strip_shyps_warning);
  4121 
  4122 
  4123 
  4124 New in Isabelle98-1 (October 1998)
  4125 ----------------------------------
  4126 
  4127 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4128 
  4129 * several changes of automated proof tools;
  4130 
  4131 * HOL: major changes to the inductive and datatype packages, including
  4132 some minor incompatibilities of theory syntax;
  4133 
  4134 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4135 called `inj_on';
  4136 
  4137 * HOL: removed duplicate thms in Arith:
  4138   less_imp_add_less  should be replaced by  trans_less_add1
  4139   le_imp_add_le      should be replaced by  trans_le_add1
  4140 
  4141 * HOL: unary minus is now overloaded (new type constraints may be
  4142 required);
  4143 
  4144 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4145 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4146 now taken as an integer constant.
  4147 
  4148 * Pure: ML function 'theory_of' renamed to 'theory';
  4149 
  4150 
  4151 *** Proof tools ***
  4152 
  4153 * Simplifier:
  4154   1. Asm_full_simp_tac is now more aggressive.
  4155      1. It will sometimes reorient premises if that increases their power to
  4156         simplify.
  4157      2. It does no longer proceed strictly from left to right but may also
  4158         rotate premises to achieve further simplification.
  4159      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4160      old Asm_full_simp_tac in that it does not rotate premises.
  4161   2. The simplifier now knows a little bit about nat-arithmetic.
  4162 
  4163 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4164 allows for selected deletion of wrappers, by introduction of names for
  4165 wrapper functionals.  This implies that addbefore, addSbefore,
  4166 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4167 and that adding two tactics with the same name overwrites the first
  4168 one (emitting a warning).
  4169   type wrapper = (int -> tactic) -> (int -> tactic)
  4170   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4171   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4172   delWrapper, delSWrapper: claset *  string            -> claset
  4173   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4174 
  4175 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4176 semantics; addbefore now affects only the unsafe part of step_tac
  4177 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4178 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4179 by Force_tac;
  4180 
  4181 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4182 compWrapper; added safe wrapper (and access functions for it);
  4183 
  4184 * HOL/split_all_tac is now much faster and fails if there is nothing
  4185 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4186 and the names of the automatically generated variables have changed.
  4187 split_all_tac has moved within claset() from unsafe wrappers to safe
  4188 wrappers, which means that !!-bound variables are split much more
  4189 aggressively, and safe_tac and clarify_tac now split such variables.
  4190 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4191 Note: the same holds for record_split_tac, which does the job of
  4192 split_all_tac for record fields.
  4193 
  4194 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4195 permanently to the default simpset using Addsplits just like
  4196 Addsimps. They can be removed via Delsplits just like
  4197 Delsimps. Lower-case versions are also available.
  4198 
  4199 * HOL/Simplifier: The rule split_if is now part of the default
  4200 simpset. This means that the simplifier will eliminate all occurrences
  4201 of if-then-else in the conclusion of a goal. To prevent this, you can
  4202 either remove split_if completely from the default simpset by
  4203 `Delsplits [split_if]' or remove it in a specific call of the
  4204 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4205 other case splitting rules to/from the default simpset: every datatype
  4206 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4207 t is the name of the datatype).
  4208 
  4209 * Classical reasoner / Simplifier combination: new force_tac (and
  4210 derivatives Force_tac, force) combines rewriting and classical
  4211 reasoning (and whatever other tools) similarly to auto_tac, but is
  4212 aimed to solve the given subgoal completely.
  4213 
  4214 
  4215 *** General ***
  4216 
  4217 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4218 and `goalw': the theory is no longer needed as an explicit argument -
  4219 the current theory context is used; assumptions are no longer returned
  4220 at the ML-level unless one of them starts with ==> or !!; it is
  4221 recommended to convert to these new commands using isatool fixgoal
  4222 (backup your sources first!);
  4223 
  4224 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4225 the current theory context, and 'theory' to lookup stored theories;
  4226 
  4227 * new theory section 'locale' for declaring constants, assumptions and
  4228 definitions that have local scope;
  4229 
  4230 * new theory section 'nonterminals' for purely syntactic types;
  4231 
  4232 * new theory section 'setup' for generic ML setup functions
  4233 (e.g. package initialization);
  4234 
  4235 * the distribution now includes Isabelle icons: see
  4236 lib/logo/isabelle-{small,tiny}.xpm;
  4237 
  4238 * isatool install - install binaries with absolute references to
  4239 ISABELLE_HOME/bin;
  4240 
  4241 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4242 
  4243 * print mode 'emacs' reserved for Isamode;
  4244 
  4245 * support multiple print (ast) translations per constant name;
  4246 
  4247 * theorems involving oracles are now printed with a suffixed [!];
  4248 
  4249 
  4250 *** HOL ***
  4251 
  4252 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4253 
  4254 * HOL/inductive package reorganized and improved: now supports mutual
  4255 definitions such as
  4256 
  4257   inductive EVEN ODD
  4258     intrs
  4259       null "0 : EVEN"
  4260       oddI "n : EVEN ==> Suc n : ODD"
  4261       evenI "n : ODD ==> Suc n : EVEN"
  4262 
  4263 new theorem list "elims" contains an elimination rule for each of the
  4264 recursive sets; inductive definitions now handle disjunctive premises
  4265 correctly (also ZF);
  4266 
  4267 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4268 "mutual_induct" no longer exists - the induction rule is always
  4269 contained in "induct";
  4270 
  4271 
  4272 * HOL/datatype package re-implemented and greatly improved: now
  4273 supports mutually recursive datatypes such as
  4274 
  4275   datatype
  4276     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4277             | SUM ('a aexp) ('a aexp)
  4278             | DIFF ('a aexp) ('a aexp)
  4279             | NUM 'a
  4280   and
  4281     'a bexp = LESS ('a aexp) ('a aexp)
  4282             | AND ('a bexp) ('a bexp)
  4283             | OR ('a bexp) ('a bexp)
  4284 
  4285 as well as indirectly recursive datatypes such as
  4286 
  4287   datatype
  4288     ('a, 'b) term = Var 'a
  4289                   | App 'b ((('a, 'b) term) list)
  4290 
  4291 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4292 induction on mutually / indirectly recursive datatypes.
  4293 
  4294 Primrec equations are now stored in theory and can be accessed via
  4295 <function_name>.simps.
  4296 
  4297 INCOMPATIBILITIES:
  4298 
  4299   - Theories using datatypes must now have theory Datatype as an
  4300     ancestor.
  4301   - The specific <typename>.induct_tac no longer exists - use the
  4302     generic induct_tac instead.
  4303   - natE has been renamed to nat.exhaust - use exhaust_tac
  4304     instead of res_inst_tac ... natE. Note that the variable
  4305     names in nat.exhaust differ from the names in natE, this
  4306     may cause some "fragile" proofs to fail.
  4307   - The theorems split_<typename>_case and split_<typename>_case_asm
  4308     have been renamed to <typename>.split and <typename>.split_asm.
  4309   - Since default sorts of type variables are now handled correctly,
  4310     some datatype definitions may have to be annotated with explicit
  4311     sort constraints.
  4312   - Primrec definitions no longer require function name and type
  4313     of recursive argument.
  4314 
  4315 Consider using isatool fixdatatype to adapt your theories and proof
  4316 scripts to the new package (backup your sources first!).
  4317 
  4318 
  4319 * HOL/record package: considerably improved implementation; now
  4320 includes concrete syntax for record types, terms, updates; theorems
  4321 for surjective pairing and splitting !!-bound record variables; proof
  4322 support is as follows:
  4323 
  4324   1) standard conversions (selectors or updates applied to record
  4325 constructor terms) are part of the standard simpset;
  4326 
  4327   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4328 made part of standard simpset and claset via addIffs;
  4329 
  4330   3) a tactic for record field splitting (record_split_tac) is part of
  4331 the standard claset (addSWrapper);
  4332 
  4333 To get a better idea about these rules you may retrieve them via
  4334 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4335 the name of your record type.
  4336 
  4337 The split tactic 3) conceptually simplifies by the following rule:
  4338 
  4339   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4340 
  4341 Thus any record variable that is bound by meta-all will automatically
  4342 blow up into some record constructor term, consequently the
  4343 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4344 solve record problems automatically.
  4345 
  4346 
  4347 * reorganized the main HOL image: HOL/Integ and String loaded by
  4348 default; theory Main includes everything;
  4349 
  4350 * automatic simplification of integer sums and comparisons, using cancellation;
  4351 
  4352 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4353 
  4354 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4355 
  4356 * many new identities for unions, intersections, set difference, etc.;
  4357 
  4358 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4359 called split_if, split_split, split_sum_case and split_nat_case (to go
  4360 with add/delsplits);
  4361 
  4362 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4363 (?x::unit) = (); this is made part of the default simpset, which COULD
  4364 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4365 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4366 unit_abs_eta_conv is added in order to counter the effect of
  4367 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4368 %u.f();
  4369 
  4370 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4371 makes more sense);
  4372 
  4373 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4374   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4375   disjointness reasoning but breaking a few old proofs.
  4376 
  4377 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4378 to 'converse' from 'inverse' (for compatibility with ZF and some
  4379 literature);
  4380 
  4381 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4382 the well-founded relation;
  4383 
  4384 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4385     Compl A.  The "Compl" syntax remains available as input syntax for this
  4386     release ONLY.
  4387 
  4388 * HOL/Update: new theory of function updates:
  4389     f(a:=b) == %x. if x=a then b else f x
  4390 may also be iterated as in f(a:=b,c:=d,...);
  4391 
  4392 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4393 
  4394 * HOL/List:
  4395   - new function list_update written xs[i:=v] that updates the i-th
  4396     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4397   - new function `upt' written [i..j(] which generates the list
  4398     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4399     bound write [i..j], which is a shorthand for [i..j+1(].
  4400   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4401 
  4402 * HOL/Arith:
  4403   - removed 'pred' (predecessor) function;
  4404   - generalized some theorems about n-1;
  4405   - many new laws about "div" and "mod";
  4406   - new laws about greatest common divisors (see theory ex/Primes);
  4407 
  4408 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4409 instead of "inverse";
  4410 
  4411 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4412   of the multiset ordering;
  4413 
  4414 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4415   (not included by default);
  4416 
  4417 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4418 
  4419 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4420   programs, i.e. different program variables may have different types.
  4421 
  4422 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4423   [previously, this check worked only if the rewrite rule was unconditional]
  4424   Now rew can involve either definitions or equalities (either == or =).
  4425 
  4426 
  4427 *** ZF ***
  4428 
  4429 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4430   only the theorems proved on ZF.ML;
  4431 
  4432 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4433   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4434   disjointness reasoning but breaking a few old proofs.
  4435 
  4436 * ZF/Update: new theory of function updates
  4437     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4438   may also be iterated as in f(a:=b,c:=d,...);
  4439 
  4440 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4441 
  4442 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4443   [previously, this check worked only if the rewrite rule was unconditional]
  4444   Now rew can involve either definitions or equalities (either == or =).
  4445 
  4446 * case_tac provided for compatibility with HOL
  4447     (like the old excluded_middle_tac, but with subgoals swapped)
  4448 
  4449 
  4450 *** Internal programming interfaces ***
  4451 
  4452 * Pure: several new basic modules made available for general use, see
  4453 also src/Pure/README;
  4454 
  4455 * improved the theory data mechanism to support encapsulation (data
  4456 kind name replaced by private Object.kind, acting as authorization
  4457 key); new type-safe user interface via functor TheoryDataFun; generic
  4458 print_data function becomes basically useless;
  4459 
  4460 * removed global_names compatibility flag -- all theory declarations
  4461 are qualified by default;
  4462 
  4463 * module Pure/Syntax now offers quote / antiquote translation
  4464 functions (useful for Hoare logic etc. with implicit dependencies);
  4465 see HOL/ex/Antiquote for an example use;
  4466 
  4467 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4468 cterm -> thm;
  4469 
  4470 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4471 subgoal;
  4472 
  4473 * Display.print_goals function moved to Locale.print_goals;
  4474 
  4475 * standard print function for goals supports current_goals_markers
  4476 variable for marking begin of proof, end of proof, start of goal; the
  4477 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4478 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4479 for example;
  4480 
  4481 
  4482 
  4483 New in Isabelle98 (January 1998)
  4484 --------------------------------
  4485 
  4486 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4487 
  4488 * changed lexical syntax of terms / types: dots made part of long
  4489 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4490 
  4491 * simpset (and claset) reference variable replaced by functions
  4492 simpset / simpset_ref;
  4493 
  4494 * no longer supports theory aliases (via merge) and non-trivial
  4495 implicit merge of thms' signatures;
  4496 
  4497 * most internal names of constants changed due to qualified names;
  4498 
  4499 * changed Pure/Sequence interface (see Pure/seq.ML);
  4500 
  4501 
  4502 *** General Changes ***
  4503 
  4504 * hierachically structured name spaces (for consts, types, axms, thms
  4505 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4506 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4507 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4508 long_names for fully qualified output names; NOTE: ML programs
  4509 (special tactics, packages etc.) referring to internal names may have
  4510 to be adapted to cope with fully qualified names; in case of severe
  4511 backward campatibility problems try setting 'global_names' at compile
  4512 time to have enrything declared within a flat name space; one may also
  4513 fine tune name declarations in theories via the 'global' and 'local'
  4514 section;
  4515 
  4516 * reimplemented the implicit simpset and claset using the new anytype
  4517 data filed in signatures; references simpset:simpset ref etc. are
  4518 replaced by functions simpset:unit->simpset and
  4519 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4520 to patch your ML files accordingly;
  4521 
  4522 * HTML output now includes theory graph data for display with Java
  4523 applet or isatool browser; data generated automatically via isatool
  4524 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4525 
  4526 * defs may now be conditional; improved rewrite_goals_tac to handle
  4527 conditional equations;
  4528 
  4529 * defs now admits additional type arguments, using TYPE('a) syntax;
  4530 
  4531 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4532 creates a new theory node; implicit merge of thms' signatures is
  4533 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4534 transfer:theory->thm->thm in (rare) cases;
  4535 
  4536 * improved handling of draft signatures / theories; draft thms (and
  4537 ctyps, cterms) are automatically promoted to real ones;
  4538 
  4539 * slightly changed interfaces for oracles: admit many per theory, named
  4540 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4541 
  4542 * print_goals: optional output of const types (set show_consts and
  4543 show_types);
  4544 
  4545 * improved output of warnings (###) and errors (***);
  4546 
  4547 * subgoal_tac displays a warning if the new subgoal has type variables;
  4548 
  4549 * removed old README and Makefiles;
  4550 
  4551 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4552 
  4553 * removed obsolete init_pps and init_database;
  4554 
  4555 * deleted the obsolete tactical STATE, which was declared by
  4556     fun STATE tacfun st = tacfun st st;
  4557 
  4558 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4559 (which abbreviates $HOME);
  4560 
  4561 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4562 use isatool fixseq to adapt your ML programs (this works for fully
  4563 qualified references to the Sequence structure only!);
  4564 
  4565 * use_thy no longer requires writable current directory; it always
  4566 reloads .ML *and* .thy file, if either one is out of date;
  4567 
  4568 
  4569 *** Classical Reasoner ***
  4570 
  4571 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4572 tactics that use classical reasoning to simplify a subgoal without
  4573 splitting it into several subgoals;
  4574 
  4575 * Safe_tac: like safe_tac but uses the default claset;
  4576 
  4577 
  4578 *** Simplifier ***
  4579 
  4580 * added simplification meta rules:
  4581     (asm_)(full_)simplify: simpset -> thm -> thm;
  4582 
  4583 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4584 logics (again);
  4585 
  4586 * added prems argument to simplification procedures;
  4587 
  4588 * HOL, FOL, ZF: added infix function `addsplits':
  4589   instead of `<simpset> setloop (split_tac <thms>)'
  4590   you can simply write `<simpset> addsplits <thms>'
  4591 
  4592 
  4593 *** Syntax ***
  4594 
  4595 * TYPE('a) syntax for type reflection terms;
  4596 
  4597 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4598 
  4599 * pretty printer: changed order of mixfix annotation preference (again!);
  4600 
  4601 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4602 
  4603 
  4604 *** HOL ***
  4605 
  4606 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4607   with `addloop' of the simplifier to faciliate case splitting in premises.
  4608 
  4609 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4610 
  4611 * HOL/Auth: new protocol proofs including some for the Internet
  4612   protocol TLS;
  4613 
  4614 * HOL/Map: new theory of `maps' a la VDM;
  4615 
  4616 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4617 cancelling out common nat summands from =, <, <= (in)equalities, or
  4618 differences; simplification procedures nat_cancel_factor for
  4619 cancelling common factor from =, <, <= (in)equalities over natural
  4620 sums; nat_cancel contains both kinds of procedures, it is installed by
  4621 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4622 
  4623 * HOL/simplifier: terms of the form
  4624   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4625   are rewritten to
  4626   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4627   and those of the form
  4628   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4629   are rewritten to
  4630   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4631 
  4632 * HOL/datatype
  4633   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4634 
  4635   P(t_case f1 ... fn x) =
  4636      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4637         ...
  4638        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4639      )
  4640 
  4641   and a theorem `split_t_case_asm' of the form
  4642 
  4643   P(t_case f1 ... fn x) =
  4644     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4645         ...
  4646        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4647      )
  4648   which can be added to a simpset via `addsplits'. The existing theorems
  4649   expand_list_case and expand_option_case have been renamed to
  4650   split_list_case and split_option_case.
  4651 
  4652 * HOL/Arithmetic:
  4653   - `pred n' is automatically converted to `n-1'.
  4654     Users are strongly encouraged not to use `pred' any longer,
  4655     because it will disappear altogether at some point.
  4656   - Users are strongly encouraged to write "0 < n" rather than
  4657     "n ~= 0". Theorems and proof tools have been modified towards this
  4658     `standard'.
  4659 
  4660 * HOL/Lists:
  4661   the function "set_of_list" has been renamed "set" (and its theorems too);
  4662   the function "nth" now takes its arguments in the reverse order and
  4663   has acquired the infix notation "!" as in "xs!n".
  4664 
  4665 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4666 
  4667 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4668   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4669 
  4670 * HOL/record: extensible records with schematic structural subtyping
  4671 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4672 still lacks various theorems and concrete record syntax;
  4673 
  4674 
  4675 *** HOLCF ***
  4676 
  4677 * removed "axioms" and "generated by" sections;
  4678 
  4679 * replaced "ops" section by extended "consts" section, which is capable of
  4680   handling the continuous function space "->" directly;
  4681 
  4682 * domain package:
  4683   . proves theorems immediately and stores them in the theory,
  4684   . creates hierachical name space,
  4685   . now uses normal mixfix annotations (instead of cinfix...),
  4686   . minor changes to some names and values (for consistency),
  4687   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4688   . separator between mutual domain defs: changed "," to "and",
  4689   . improved handling of sort constraints;  now they have to
  4690     appear on the left-hand side of the equations only;
  4691 
  4692 * fixed LAM <x,y,zs>.b syntax;
  4693 
  4694 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4695 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4696 
  4697 
  4698 *** FOL and ZF ***
  4699 
  4700 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4701   with `addloop' of the simplifier to faciliate case splitting in premises.
  4702 
  4703 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4704 in HOL, they strip ALL and --> from proved theorems;
  4705 
  4706 
  4707 
  4708 New in Isabelle94-8 (May 1997)
  4709 ------------------------------
  4710 
  4711 *** General Changes ***
  4712 
  4713 * new utilities to build / run / maintain Isabelle etc. (in parts
  4714 still somewhat experimental); old Makefiles etc. still functional;
  4715 
  4716 * new 'Isabelle System Manual';
  4717 
  4718 * INSTALL text, together with ./configure and ./build scripts;
  4719 
  4720 * reimplemented type inference for greater efficiency, better error
  4721 messages and clean internal interface;
  4722 
  4723 * prlim command for dealing with lots of subgoals (an easier way of
  4724 setting goals_limit);
  4725 
  4726 
  4727 *** Syntax ***
  4728 
  4729 * supports alternative (named) syntax tables (parser and pretty
  4730 printer); internal interface is provided by add_modesyntax(_i);
  4731 
  4732 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4733 be used in conjunction with the Isabelle symbol font; uses the
  4734 "symbols" syntax table;
  4735 
  4736 * added token_translation interface (may translate name tokens in
  4737 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4738 the current print_mode); IMPORTANT: user print translation functions
  4739 are responsible for marking newly introduced bounds
  4740 (Syntax.mark_boundT);
  4741 
  4742 * token translations for modes "xterm" and "xterm_color" that display
  4743 names in bold, underline etc. or colors (which requires a color
  4744 version of xterm);
  4745 
  4746 * infixes may now be declared with names independent of their syntax;
  4747 
  4748 * added typed_print_translation (like print_translation, but may
  4749 access type of constant);
  4750 
  4751 
  4752 *** Classical Reasoner ***
  4753 
  4754 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4755 some limitations.  Blast_tac...
  4756   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4757   + ignores elimination rules that don't have the correct format
  4758         (the conclusion MUST be a formula variable)
  4759   + ignores types, which can make HOL proofs fail
  4760   + rules must not require higher-order unification, e.g. apply_type in ZF
  4761     [message "Function Var's argument not a bound variable" relates to this]
  4762   + its proof strategy is more general but can actually be slower
  4763 
  4764 * substitution with equality assumptions no longer permutes other
  4765 assumptions;
  4766 
  4767 * minor changes in semantics of addafter (now called addaltern); renamed
  4768 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4769 (and access functions for it);
  4770 
  4771 * improved combination of classical reasoner and simplifier:
  4772   + functions for handling clasimpsets
  4773   + improvement of addss: now the simplifier is called _after_ the
  4774     safe steps.
  4775   + safe variant of addss called addSss: uses safe simplifications
  4776     _during_ the safe steps. It is more complete as it allows multiple
  4777     instantiations of unknowns (e.g. with slow_tac).
  4778 
  4779 *** Simplifier ***
  4780 
  4781 * added interface for simplification procedures (functions that
  4782 produce *proven* rewrite rules on the fly, depending on current
  4783 redex);
  4784 
  4785 * ordering on terms as parameter (used for ordered rewriting);
  4786 
  4787 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4788 
  4789 * the solver is now split into a safe and an unsafe part.
  4790 This should be invisible for the normal user, except that the
  4791 functions setsolver and addsolver have been renamed to setSolver and
  4792 addSolver; added safe_asm_full_simp_tac;
  4793 
  4794 
  4795 *** HOL ***
  4796 
  4797 * a generic induction tactic `induct_tac' which works for all datatypes and
  4798 also for type `nat';
  4799 
  4800 * a generic case distinction tactic `exhaust_tac' which works for all
  4801 datatypes and also for type `nat';
  4802 
  4803 * each datatype comes with a function `size';
  4804 
  4805 * patterns in case expressions allow tuple patterns as arguments to
  4806 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4807 
  4808 * primrec now also works with type nat;
  4809 
  4810 * recdef: a new declaration form, allows general recursive functions to be
  4811 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4812 
  4813 * the constant for negation has been renamed from "not" to "Not" to
  4814 harmonize with FOL, ZF, LK, etc.;
  4815 
  4816 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4817 infinite lists;
  4818 
  4819 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4820 
  4821 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4822 problems in commutative rings, using axiomatic type classes for + and *;
  4823 
  4824 * more examples in HOL/MiniML and HOL/Auth;
  4825 
  4826 * more default rewrite rules for quantifiers, union/intersection;
  4827 
  4828 * a new constant `arbitrary == @x.False';
  4829 
  4830 * HOLCF/IOA replaces old HOL/IOA;
  4831 
  4832 * HOLCF changes: derived all rules and arities
  4833   + axiomatic type classes instead of classes
  4834   + typedef instead of faking type definitions
  4835   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4836   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4837   + eliminated the types void, one, tr
  4838   + use unit lift and bool lift (with translations) instead of one and tr
  4839   + eliminated blift from Lift3.thy (use Def instead of blift)
  4840   all eliminated rules are derived as theorems --> no visible changes ;
  4841 
  4842 
  4843 *** ZF ***
  4844 
  4845 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4846 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4847 as ZF_cs addSIs [equalityI];
  4848 
  4849 
  4850 
  4851 New in Isabelle94-7 (November 96)
  4852 ---------------------------------
  4853 
  4854 * allowing negative levels (as offsets) in prlev and choplev;
  4855 
  4856 * super-linear speedup for large simplifications;
  4857 
  4858 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4859 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4860 FAIL); can suppress it using the command Delsimps (ex_simps @
  4861 all_simps); De Morgan laws are also now included, by default;
  4862 
  4863 * improved printing of ==>  :  ~:
  4864 
  4865 * new object-logic "Sequents" adds linear logic, while replacing LK
  4866 and Modal (thanks to Sara Kalvala);
  4867 
  4868 * HOL/Auth: correctness proofs for authentication protocols;
  4869 
  4870 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4871 examples on HOL/Auth);
  4872 
  4873 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4874 the rewriter and classical reasoner simultaneously;
  4875 
  4876 * function uresult no longer returns theorems in "standard" format;
  4877 regain previous version by: val uresult = standard o uresult;
  4878 
  4879 
  4880 
  4881 New in Isabelle94-6
  4882 -------------------
  4883 
  4884 * oracles -- these establish an interface between Isabelle and trusted
  4885 external reasoners, which may deliver results as theorems;
  4886 
  4887 * proof objects (in particular record all uses of oracles);
  4888 
  4889 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4890 
  4891 * "constdefs" section in theory files;
  4892 
  4893 * "primrec" section (HOL) no longer requires names;
  4894 
  4895 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4896 
  4897 
  4898 
  4899 New in Isabelle94-5
  4900 -------------------
  4901 
  4902 * reduced space requirements;
  4903 
  4904 * automatic HTML generation from theories;
  4905 
  4906 * theory files no longer require "..." (quotes) around most types;
  4907 
  4908 * new examples, including two proofs of the Church-Rosser theorem;
  4909 
  4910 * non-curried (1994) version of HOL is no longer distributed;
  4911 
  4912 
  4913 
  4914 New in Isabelle94-4
  4915 -------------------
  4916 
  4917 * greatly reduced space requirements;
  4918 
  4919 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4920 
  4921 * searchable theorem database (see the section "Retrieving theorems" on
  4922 page 8 of the Reference Manual);
  4923 
  4924 * new examples, including Grabczewski's monumental case study of the
  4925 Axiom of Choice;
  4926 
  4927 * The previous version of HOL renamed to Old_HOL;
  4928 
  4929 * The new version of HOL (previously called CHOL) uses a curried syntax
  4930 for functions.  Application looks like f a b instead of f(a,b);
  4931 
  4932 * Mutually recursive inductive definitions finally work in HOL;
  4933 
  4934 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4935 translates to the operator "split";
  4936 
  4937 
  4938 
  4939 New in Isabelle94-3
  4940 -------------------
  4941 
  4942 * new infix operator, addss, allowing the classical reasoner to
  4943 perform simplification at each step of its search.  Example:
  4944         fast_tac (cs addss ss)
  4945 
  4946 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4947 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4948 look like (a,b) instead of <a,b>;
  4949 
  4950 * PLEASE NOTE: CHOL will eventually replace HOL!
  4951 
  4952 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4953 It translates to the operator "split".  A new theory of integers is available;
  4954 
  4955 * In ZF, integer numerals now denote two's-complement binary integers.
  4956 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4957 
  4958 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4959 of the Axiom of Choice;
  4960 
  4961 
  4962 
  4963 New in Isabelle94-2
  4964 -------------------
  4965 
  4966 * Significantly faster resolution;
  4967 
  4968 * the different sections in a .thy file can now be mixed and repeated
  4969 freely;
  4970 
  4971 * Database of theorems for FOL, HOL and ZF.  New
  4972 commands including qed, qed_goal and bind_thm store theorems in the database.
  4973 
  4974 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4975 a given theory (thms_of), or find out what theory a theorem was proved in
  4976 (theory_of_thm);
  4977 
  4978 * Bugs fixed in the inductive definition and datatype packages;
  4979 
  4980 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4981 and HOL_dup_cs obsolete;
  4982 
  4983 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4984 have been removed;
  4985 
  4986 * Simpler definition of function space in ZF;
  4987 
  4988 * new results about cardinal and ordinal arithmetic in ZF;
  4989 
  4990 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4991 types;
  4992 
  4993 
  4994 $Id$