NEWS
author wenzelm
Wed Oct 11 22:55:20 2006 +0200 (2006-10-11)
changeset 20983 d4500b9b220e
parent 20951 868120282837
child 20988 0887d0dd3210
permissions -rw-r--r--
added begin parser;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory syntax: the header format ``theory A = B + C:'' has been
    10 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    11 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    12 
    13 * Theory syntax: the old non-Isar theory file format has been
    14 discontinued altogether.  Note that ML proof scripts may still be used
    15 with Isar theories; migration is usually quite simple with the ML
    16 function use_legacy_bindings.  INCOMPATIBILITY.
    17 
    18 * Theory syntax: some popular names (e.g. "class", "if", "fun") are
    19 now keywords.  INCOMPATIBILITY, use double quotes.
    20 
    21 * Legacy goal package: reduced interface to the bare minimum required
    22 to keep existing proof scripts running.  Most other user-level
    23 functions are now part of the OldGoals structure, which is *not* open
    24 by default (consider isatool expandshort before open OldGoals).
    25 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    26 these tend to cause confusion about the actual goal (!) context being
    27 used here, which is not necessarily the same as the_context().
    28 
    29 * Command 'find_theorems': support "*" wildcard in "name:" criterion.
    30 
    31 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    32 by default, which means that "prems" (and also "fixed variables") are
    33 suppressed from proof state output.  Note that the ProofGeneral
    34 settings mechanism allows to change and save options persistently, but
    35 older versions of Isabelle will fail to start up if a negative prems
    36 limit is imposed.
    37 
    38 
    39 *** Document preparation ***
    40 
    41 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    42 check the given source text as ML type/structure, printing verbatim.
    43 
    44 
    45 *** Pure ***
    46 
    47 * class_package.ML offers a combination of axclasses and locales to
    48 achieve Haskell-like type classes in Isabelle. See
    49 HOL/ex/Classpackage.thy for examples.
    50 
    51 * Yet another code generator framework allows to generate executable
    52 code for ML and Haskell (including "class"es). A short usage sketch:
    53 
    54     internal compilation:
    55         code_gen <list of constants (term syntax)> (SML -)
    56     writing SML code to a file:
    57         code_gen <list of constants (term syntax)> (SML <filename>)
    58     writing Haskell code to a bunch of files:
    59         code_gen <list of constants (term syntax)> (Haskell <filename>)
    60 
    61 Reasonable default setup of framework in HOL/Main.
    62 
    63 See HOL/ex/Code*.thy for examples.
    64 
    65 Theorem attributs for selecting and transforming function equations theorems:
    66 
    67     [code fun]:       select a theorem as function equation for a specific constant
    68     [code nofun]:     deselect a theorem as function equation for a specific constant
    69     [code inline]:    select an equation theorem for unfolding (inlining) in place
    70     [code noinline]:  deselect an equation theorem for unfolding (inlining) in place
    71 
    72 User-defined serializations (target in {SML, Haskell}):
    73 
    74     code_const <and-list of constants (term syntax)>
    75       {(target) <and-list of const target syntax>}+
    76 
    77     code_type <and-list of type constructors>
    78       {(target) <and-list of type target syntax>}+
    79 
    80     code_instance <and-list of instances>
    81       {(target)}+
    82         where instance ::= <type constructor> :: <class>
    83 
    84     code_class <and_list of classes>
    85       {(target) <and-list of class target syntax>}+
    86         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
    87 
    88 For code_instance and code_class, target SML is silently ignored.
    89 
    90 See HOL theories and HOL/ex/Code*.thy for usage examples.
    91 
    92 * Command 'no_translations' removes translation rules from theory
    93 syntax.
    94 
    95 * Overloaded definitions are now actually checked for acyclic
    96 dependencies.  The overloading scheme is slightly more general than
    97 that of Haskell98, although Isabelle does not demand an exact
    98 correspondence to type class and instance declarations.
    99 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   100 exotic versions of overloading -- at the discretion of the user!
   101 
   102 Polymorphic constants are represented via type arguments, i.e. the
   103 instantiation that matches an instance against the most general
   104 declaration given in the signature.  For example, with the declaration
   105 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   106 as c(nat).  Overloading is essentially simultaneous structural
   107 recursion over such type arguments.  Incomplete specification patterns
   108 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   109 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   110 Command 'print_theory' outputs the normalized system of recursive
   111 equations, see section "definitions".
   112 
   113 * Isar: improper proof element 'guess' is like 'obtain', but derives
   114 the obtained context from the course of reasoning!  For example:
   115 
   116   assume "EX x y. A x & B y"   -- "any previous fact"
   117   then guess x and y by clarify
   118 
   119 This technique is potentially adventurous, depending on the facts and
   120 proof tools being involved here.
   121 
   122 * Isar: known facts from the proof context may be specified as literal
   123 propositions, using ASCII back-quote syntax.  This works wherever
   124 named facts used to be allowed so far, in proof commands, proof
   125 methods, attributes etc.  Literal facts are retrieved from the context
   126 according to unification of type and term parameters.  For example,
   127 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   128 theorems in the current context, then these are valid literal facts:
   129 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   130 
   131 There is also a proof method "fact" which does the same composition
   132 for explicit goal states, e.g. the following proof texts coincide with
   133 certain special cases of literal facts:
   134 
   135   have "A" by fact                 ==  note `A`
   136   have "A ==> B" by fact           ==  note `A ==> B`
   137   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   138   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   139 
   140 * Isar: ":" (colon) is no longer a symbolic identifier character in
   141 outer syntax.  Thus symbolic identifiers may be used without
   142 additional white space in declarations like this: ``assume *: A''.
   143 
   144 * Isar: 'print_facts' prints all local facts of the current context,
   145 both named and unnamed ones.
   146 
   147 * Isar: 'def' now admits simultaneous definitions, e.g.:
   148 
   149   def x == "t" and y == "u"
   150 
   151 * Isar: added command 'unfolding', which is structurally similar to
   152 'using', but affects both the goal state and facts by unfolding given
   153 rewrite rules.  Thus many occurrences of the 'unfold' method or
   154 'unfolded' attribute may be replaced by first-class proof text.
   155 
   156 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   157 and command 'unfolding' now all support object-level equalities
   158 (potentially conditional).  The underlying notion of rewrite rule is
   159 analogous to the 'rule_format' attribute, but *not* that of the
   160 Simplifier (which is usually more generous).
   161 
   162 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   163 method expression within a sandbox consisting of the first N
   164 sub-goals, which need to exist.  For example, ``simp_all [3]''
   165 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   166 simplifies all new goals that emerge from applying rule foo to the
   167 originally first one.
   168 
   169 * Isar: schematic goals are no longer restricted to higher-order
   170 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   171 expected.
   172 
   173 * Isar: the conclusion of a long theorem statement is now either
   174 'shows' (a simultaneous conjunction, as before), or 'obtains'
   175 (essentially a disjunction of cases with local parameters and
   176 assumptions).  The latter allows to express general elimination rules
   177 adequately; in this notation common elimination rules look like this:
   178 
   179   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   180     assumes "EX x. P x"
   181     obtains x where "P x"
   182 
   183   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   184     assumes "A & B"
   185     obtains A and B
   186 
   187   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   188     assumes "A | B"
   189     obtains
   190       A
   191     | B
   192 
   193 The subsequent classical rules even refer to the formal "thesis"
   194 explicitly:
   195 
   196   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   197     obtains "~ thesis"
   198 
   199   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   200     obtains "thesis ==> something"
   201 
   202 The actual proof of an 'obtains' statement is analogous to that of the
   203 Isar proof element 'obtain', only that there may be several cases.
   204 Optional case names may be specified in parentheses; these will be
   205 available both in the present proof and as annotations in the
   206 resulting rule, for later use with the 'cases' method (cf. attribute
   207 case_names).
   208 
   209 * Isar: 'print_statement' prints theorems from the current theory or
   210 proof context in long statement form, according to the syntax of a
   211 top-level lemma.
   212 
   213 * Isar: 'obtain' takes an optional case name for the local context
   214 introduction rule (default "that").
   215 
   216 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   217 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   218 to occur.
   219 
   220 * Pure: syntax "CONST name" produces a fully internalized constant
   221 according to the current context.  This is particularly useful for
   222 syntax translations that should refer to internal constant
   223 representations independently of name spaces.
   224 
   225 * Isar/locales: 'const_syntax' provides a robust interface to the
   226 'syntax' primitive that also works in a locale context.  Type
   227 declaration and internal syntactic representation of given constants
   228 retrieved from the context.
   229 
   230 * Isar/locales: new derived specification elements 'axiomatization',
   231 'definition', 'abbreviation', which support type-inference, admit
   232 object-level specifications (equality, equivalence).  See also the
   233 isar-ref manual.  Examples:
   234 
   235   axiomatization
   236     eq  (infix "===" 50)
   237     where eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   238 
   239   definition
   240     "f x y = x + y + 1"
   241     "g x = f x x"
   242 
   243   abbreviation
   244     neq  (infix "=!=" 50)
   245     "x =!= y == ~ (x === y)"
   246 
   247 These specifications may be also used in a locale context.  Then the
   248 constants being introduced depend on certain fixed parameters, and the
   249 constant name is qualified by the locale base name.  An internal
   250 abbreviation takes care for convenient input and output, making the
   251 parameters implicit and using the original short name.  See also
   252 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   253 entities from a monomorphic theory.
   254 
   255 Presently, abbreviations are only available 'in' a target locale, but
   256 not inherited by general import expressions.  Also note that
   257 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   258 'translations' in common applications.
   259 
   260 Concrete syntax is attached to specified constants in internal form,
   261 independently of name spaces.  The parse tree representation is
   262 slightly different -- use 'const_syntax' instead of raw 'syntax', and
   263 'translations' with explicit "CONST" markup to accommodate this.
   264 
   265 * Isar/locales: improved parameter handling:
   266 - use of locales "var" and "struct" no longer necessary;
   267 - parameter renamings are no longer required to be injective.
   268   This enables, for example, to define a locale for endomorphisms thus:
   269   locale endom = homom mult mult h.
   270 
   271 * Isar/locales: changed the way locales with predicates are defined.
   272 Instead of accumulating the specification, the imported expression is
   273 now an interpretation.
   274 INCOMPATIBILITY: different normal form of locale expressions.
   275 In particular, in interpretations of locales with predicates,
   276 goals repesenting already interpreted fragments are not removed
   277 automatically.  Use methods `intro_locales' and `unfold_locales'; see below.
   278 
   279 * Isar/locales: new methods `intro_locales' and `unfold_locales' provide
   280 backward reasoning on locales predicates.  The methods are aware of
   281 interpretations and discharge corresponding goals.  `intro_locales' is
   282 less aggressive then `unfold_locales' and does not unfold predicates to
   283 assumptions.
   284 
   285 * Isar/locales: the order in which locale fragments are accumulated
   286 has changed.  This enables to override declarations from fragments
   287 due to interpretations -- for example, unwanted simp rules.
   288 
   289 * Provers/induct: improved internal context management to support
   290 local fixes and defines on-the-fly.  Thus explicit meta-level
   291 connectives !! and ==> are rarely required anymore in inductive goals
   292 (using object-logic connectives for this purpose has been long
   293 obsolete anyway).  The subsequent proof patterns illustrate advanced
   294 techniques of natural induction; general datatypes and inductive sets
   295 work analogously (see also src/HOL/Lambda for realistic examples).
   296 
   297 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   298 parameters:
   299 
   300   lemma
   301     fixes n :: nat and x :: 'a
   302     assumes a: "A n x"
   303     shows "P n x"
   304     using a                     -- {* make induct insert fact a *}
   305   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   306     case 0
   307     show ?case sorry
   308   next
   309     case (Suc n)
   310     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   311     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   312     show ?case sorry
   313   qed
   314 
   315 (2) This is how to perform induction over ``expressions of a certain
   316 form'', using a locally defined inductive parameter n == "a x"
   317 together with strengthening (the latter is usually required to get
   318 sufficiently flexible induction hypotheses):
   319 
   320   lemma
   321     fixes a :: "'a => nat"
   322     assumes a: "A (a x)"
   323     shows "P (a x)"
   324     using a
   325   proof (induct n == "a x" arbitrary: x)
   326     ...
   327 
   328 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   329 particular technique.
   330 
   331 (3) This is how to perform existential reasoning ('obtains' or
   332 'obtain') by induction, while avoiding explicit object-logic
   333 encodings:
   334 
   335   lemma
   336     fixes n :: nat
   337     obtains x :: 'a where "P n x" and "Q n x"
   338   proof (induct n arbitrary: thesis)
   339     case 0
   340     obtain x where "P 0 x" and "Q 0 x" sorry
   341     then show thesis by (rule 0)
   342   next
   343     case (Suc n)
   344     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   345     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   346     then show thesis by (rule Suc.prems)
   347   qed
   348 
   349 Here the 'arbitrary: thesis' specification essentially modifies the
   350 scope of the formal thesis parameter, in order to the get the whole
   351 existence statement through the induction as expected.
   352 
   353 * Provers/induct: mutual induction rules are now specified as a list
   354 of rule sharing the same induction cases.  HOL packages usually
   355 provide foo_bar.inducts for mutually defined items foo and bar
   356 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   357 specify mutual induction rules differently, i.e. like this:
   358 
   359   (induct rule: foo_bar.inducts)
   360   (induct set: foo bar)
   361   (induct type: foo bar)
   362 
   363 The ML function ProjectRule.projections turns old-style rules into the
   364 new format.
   365 
   366 * Provers/induct: improved handling of simultaneous goals.  Instead of
   367 introducing object-level conjunction, the statement is now split into
   368 several conclusions, while the corresponding symbolic cases are
   369 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   370 explicitly.  For example:
   371 
   372   lemma
   373     fixes n :: nat
   374     shows "P n" and "Q n"
   375   proof (induct n)
   376     case 0 case 1
   377     show "P 0" sorry
   378   next
   379     case 0 case 2
   380     show "Q 0" sorry
   381   next
   382     case (Suc n) case 1
   383     note `P n` and `Q n`
   384     show "P (Suc n)" sorry
   385   next
   386     case (Suc n) case 2
   387     note `P n` and `Q n`
   388     show "Q (Suc n)" sorry
   389   qed
   390 
   391 The split into subcases may be deferred as follows -- this is
   392 particularly relevant for goal statements with local premises.
   393 
   394   lemma
   395     fixes n :: nat
   396     shows "A n ==> P n" and "B n ==> Q n"
   397   proof (induct n)
   398     case 0
   399     {
   400       case 1
   401       note `A 0`
   402       show "P 0" sorry
   403     next
   404       case 2
   405       note `B 0`
   406       show "Q 0" sorry
   407     }
   408   next
   409     case (Suc n)
   410     note `A n ==> P n` and `B n ==> Q n`
   411     {
   412       case 1
   413       note `A (Suc n)`
   414       show "P (Suc n)" sorry
   415     next
   416       case 2
   417       note `B (Suc n)`
   418       show "Q (Suc n)" sorry
   419     }
   420   qed
   421 
   422 If simultaneous goals are to be used with mutual rules, the statement
   423 needs to be structured carefully as a two-level conjunction, using
   424 lists of propositions separated by 'and':
   425 
   426   lemma
   427     shows "a : A ==> P1 a"
   428           "a : A ==> P2 a"
   429       and "b : B ==> Q1 b"
   430           "b : B ==> Q2 b"
   431           "b : B ==> Q3 b"
   432   proof (induct set: A B)
   433 
   434 * Provers/induct: support coinduction as well.  See
   435 src/HOL/Library/Coinductive_List.thy for various examples.
   436 
   437 * Attribute "symmetric" produces result with standardized schematic
   438 variables (index 0).  Potential INCOMPATIBILITY.
   439 
   440 * Simplifier: by default the simplifier trace only shows top level rewrites
   441 now. That is, trace_simp_depth_limit is set to 1 by default. Thus there is
   442 less danger of being flooded by the trace. The trace indicates where parts
   443 have been suppressed.
   444   
   445 * Provers/classical: removed obsolete classical version of elim_format
   446 attribute; classical elim/dest rules are now treated uniformly when
   447 manipulating the claset.
   448 
   449 * Provers/classical: stricter checks to ensure that supplied intro,
   450 dest and elim rules are well-formed; dest and elim rules must have at
   451 least one premise.
   452 
   453 * Provers/classical: attributes dest/elim/intro take an optional
   454 weight argument for the rule (just as the Pure versions).  Weights are
   455 ignored by automated tools, but determine the search order of single
   456 rule steps.
   457 
   458 * Syntax: input syntax now supports dummy variable binding "%_. b",
   459 where the body does not mention the bound variable.  Note that dummy
   460 patterns implicitly depend on their context of bounds, which makes
   461 "{_. _}" match any set comprehension as expected.  Potential
   462 INCOMPATIBILITY -- parse translations need to cope with syntactic
   463 constant "_idtdummy" in the binding position.
   464 
   465 * Syntax: removed obsolete syntactic constant "_K" and its associated
   466 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   467 for example "A -> B" => "Pi A (%_. B)".
   468 
   469 * Pure: 'class_deps' command visualizes the subclass relation, using
   470 the graph browser tool.
   471 
   472 * Pure: 'print_theory' now suppresses entities with internal name
   473 (trailing "_") by default; use '!' option for full details.
   474 
   475 
   476 *** HOL ***
   477 
   478 * Renamed constants in HOL.thy:
   479     0      ~> HOL.zero
   480     1      ~> HOL.one
   481 INCOMPATIBILITY: ML code directly refering to constant names may need adaption
   482 This in general only affects hand-written proof tactics, simprocs and so on.
   483 
   484 * New theory OperationalEquality providing class 'eq' with constant 'eq',
   485 allowing for code generation with polymorphic equality.
   486 
   487 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has been
   488 abandoned in favour of plain 'int'. INCOMPATIBILITY -- Significant changes
   489 for setting up numeral syntax for types:
   490 
   491   - new constants Numeral.pred and Numeral.succ instead
   492       of former Numeral.bin_pred and Numeral.bin_succ.
   493   - Use integer operations instead of bin_add, bin_mult and so on.
   494   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   495   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   496 
   497 See HOL/Integ/IntArith.thy for an example setup.
   498 
   499 * New top level command 'normal_form' computes the normal form of a term
   500 that may contain free variables. For example 'normal_form "rev[a,b,c]"'
   501 prints '[b,c,a]'. This command is suitable for heavy-duty computations
   502 because the functions are compiled to ML first.
   503 INCOMPATIBILITY: new keywords 'normal_form' must quoted when used as
   504 an identifier.
   505 
   506 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   507 25 like -->); output depends on the "iff" print_mode, the default is
   508 "A = B" (with priority 50).
   509 
   510 * Renamed constants in HOL.thy and Orderings.thy:
   511     op +   ~> HOL.plus
   512     op -   ~> HOL.minus
   513     uminus ~> HOL.uminus
   514     op *   ~> HOL.times
   515     op <   ~> Orderings.less
   516     op <=  ~> Orderings.less_eq
   517 
   518 Adaptions may be required in the following cases:
   519 
   520 a) User-defined constants using any of the names "plus", "minus", "times",
   521 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   522 may go wrong.
   523 INCOMPATIBILITY: use more specific names.
   524 
   525 b) Variables named "plus", "minus", "times", "less", "less_eq"
   526 INCOMPATIBILITY: use more specific names.
   527 
   528 c) Permutative equations (e.g. "a + b = b + a")
   529 Since the change of names also changes the order of terms, permutative
   530 rewrite rules may get applied in a different order. Experience shows that
   531 this is rarely the case (only two adaptions in the whole Isabelle
   532 distribution).
   533 INCOMPATIBILITY: rewrite proofs
   534 
   535 d) ML code directly refering to constant names
   536 This in general only affects hand-written proof tactics, simprocs and so on.
   537 INCOMPATIBILITY: grep your sourcecode and replace names.
   538 
   539 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   540 
   541 * Relation composition operator "op O" now has precedence 75 and binds
   542 stronger than union and intersection. INCOMPATIBILITY.
   543 
   544 * The old set interval syntax "{m..n(}" (and relatives) has been removed.
   545   Use "{m..<n}" (and relatives) instead.
   546 
   547 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   548 "t = s" to False (by simproc "neq_simproc").  For backward
   549 compatibility this can be disabled by ML "reset use_neq_simproc".
   550 
   551 * "m dvd n" where m and n are numbers is evaluated to True/False by simp.
   552 
   553 * Theorem Cons_eq_map_conv no longer has attribute `simp'.
   554 
   555 * Theorem setsum_mult renamed to setsum_right_distrib.
   556 
   557 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   558 'rule' method.
   559 
   560 * Tactics 'sat' and 'satx' reimplemented, several improvements: goals
   561 no longer need to be stated as "<prems> ==> False", equivalences (i.e.
   562 "=" on type bool) are handled, variable names of the form "lit_<n>"
   563 are no longer reserved, significant speedup.
   564 
   565 * Tactics 'sat' and 'satx' can now replay MiniSat proof traces.  zChaff is
   566 still supported as well.
   567 
   568 * inductive and datatype: provide projections of mutual rules, bundled
   569 as foo_bar.inducts;
   570 
   571 * Library: theory Infinite_Set has been moved to the library.
   572 
   573 * Library: theory Accessible_Part has been move to main HOL.
   574 
   575 * Library: added theory Coinductive_List of potentially infinite lists
   576 as greatest fixed-point.
   577 
   578 * Library: added theory AssocList which implements (finite) maps as
   579 association lists.
   580 
   581 * New proof method "evaluation" for efficiently solving a goal (i.e. a
   582 boolean expression) by compiling it to ML. The goal is "proved" (via
   583 the oracle "Evaluation") if it evaluates to True.
   584 
   585 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   586 also when invoked by the simplifier.  This results in the simplifier
   587 being more powerful on arithmetic goals.  INCOMPATIBILTY.  Set
   588 fast_arith_split_limit to 0 to obtain the old behavior.
   589 
   590 * Support for hex (0x20) and binary (0b1001) numerals. 
   591 
   592 * New method: reify eqs (t), where eqs are equations for an
   593 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   594 parameter, computes a term s::'b and a list xs::'a list and proves the
   595 theorem I xs s = t. This is also known as reification or quoting. The
   596 resulting theorem is applied to the subgoal to substitute t with I xs
   597 s.  If t is omitted, the subgoal itself is reified.
   598 
   599 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   600 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   601 where f is supposed to be a computable function (in the sense of code
   602 generattion). The method uses reify to compute s and xs as above then
   603 applies corr_thm and uses normalization by evaluation to "prove" f s =
   604 r and finally gets the theorem t = r, which is again applied to the
   605 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   606 
   607 * Reflection: Automatic refification now handels binding, an example
   608 is available in HOL/ex/ReflectionEx.thy
   609 
   610 
   611 *** HOL-Algebra ***
   612 
   613 * Method algebra is now set up via an attribute.  For examples see CRing.thy.
   614   INCOMPATIBILITY: the method is now weaker on combinations of algebraic
   615   structures.
   616 
   617 * Formalisation of ideals and the quotient construction over rings, contributed
   618   by Stephan Hohe.
   619 
   620 * Renamed `CRing.thy' to `Ring.thy'.  INCOMPATIBILITY.
   621 
   622 
   623 *** HOL-Complex ***
   624 
   625 * Theory Real: new method ferrack implements quantifier elimination
   626 for linear arithmetic over the reals. The quantifier elimination
   627 feature is used only for decision, for compatibility with arith. This
   628 means a goal is either solved or left unchanged, no simplification.
   629 
   630 
   631 *** ML ***
   632 
   633 * Pure/library:
   634 
   635 gen_rem(s) abandoned in favour of remove / subtract.
   636 INCOMPATIBILITY:
   637 rewrite "gen_rem eq (xs, x)" to "remove (eq o swap) x xs"
   638 rewrite "gen_rems eq (xs, ys)" to "subtract (eq o swap) ys xs"
   639 drop "swap" if "eq" is symmetric.
   640 
   641 * Pure/library:
   642 
   643 infixes ins ins_string ins_int have been abandoned in favour of insert.
   644 INCOMPATIBILITY: rewrite "x ins(_...) xs" to "insert (op =) x xs"
   645 
   646 * Pure/General/susp.ML:
   647 
   648 New module for delayed evaluations.
   649 
   650 * Pure/library:
   651 
   652 Semantically identical functions "equal_list" and "eq_list" have been
   653 unified to "eq_list".
   654 
   655 * Pure/library:
   656 
   657   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   658   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   659 
   660 The semantics of "burrow" is: "take a function with *simulatanously*
   661 transforms a list of value, and apply it *simulatanously* to a list of
   662 list of values of the appropriate type". Confer this with "map" which
   663 would *not* apply its argument function simulatanously but in
   664 sequence. "fold_burrow" has an additional context.
   665 
   666 Both actually avoid the usage of "unflat" since they hide away
   667 "unflat" from the user.
   668 
   669 * Pure/library: functions map2 and fold2 with curried syntax for
   670 simultanous mapping and folding:
   671 
   672     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   673     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   674 
   675 * Pure/library: indexed lists - some functions in the Isabelle library
   676 treating lists over 'a as finite mappings from [0...n] to 'a have been
   677 given more convenient names and signatures reminiscent of similar
   678 functions for alists, tables, etc:
   679 
   680   val nth: 'a list -> int -> 'a 
   681   val nth_update: int * 'a -> 'a list -> 'a list
   682   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   683   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   684 
   685 Note that fold_index starts counting at index 0, not 1 like foldln
   686 used to.
   687 
   688 * Pure/library: general ``divide_and_conquer'' combinator on lists.
   689 
   690 * Pure/General/name_mangler.ML provides a functor for generic name
   691 mangling (bijective mapping from any expression values to strings).
   692 
   693 * Pure/General/rat.ML implements rational numbers.
   694 
   695 * Pure/General/table.ML: the join operations now works via exceptions
   696 DUP/SAME instead of type option.  This is simpler in simple cases, and
   697 admits slightly more efficient complex applications.
   698 
   699 * Pure: datatype Context.generic joins theory/Proof.context and
   700 provides some facilities for code that works in either kind of
   701 context, notably GenericDataFun for uniform theory and proof data.
   702 
   703 * Pure: 'advanced' translation functions (parse_translation etc.) now
   704 use Context.generic instead of just theory.
   705 
   706 * Pure: simplified internal attribute type, which is now always
   707 Context.generic * thm -> Context.generic * thm.  Global (theory)
   708 vs. local (Proof.context) attributes have been discontinued, while
   709 minimizing code duplication.  Thm.rule_attribute and
   710 Thm.declaration_attribute build canonical attributes; see also
   711 structure Context for further operations on Context.generic, notably
   712 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   713 declarations and definitions.
   714 
   715 * Pure/kernel: consts certification ignores sort constraints given in
   716 signature declarations.  (This information is not relevant to the
   717 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE.
   718 
   719 * Pure: axiomatic type classes are now purely definitional, with
   720 explicit proofs of class axioms and super class relations performed
   721 internally.  See Pure/axclass.ML for the main internal interfaces --
   722 notably AxClass.define_class supercedes AxClass.add_axclass, and
   723 AxClass.axiomatize_class/classrel/arity supercede
   724 Sign.add_classes/classrel/arities.
   725 
   726 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
   727 global/local versions on theory vs. Proof.context have been
   728 discontinued; Attrib.syntax and Method.syntax have been adapted
   729 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
   730 attributes, methods, etc.
   731 
   732 * Pure: several functions of signature "... -> theory -> theory * ..."
   733 have been reoriented to "... -> theory -> ... * theory" in order to
   734 allow natural usage in combination with the ||>, ||>>, |-> and
   735 fold_map combinators.
   736 
   737 * Pure: primitive rule lift_rule now takes goal cterm instead of an
   738 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
   739 achieve the old behaviour.
   740 
   741 * Pure: the "Goal" constant is now called "prop", supporting a
   742 slightly more general idea of ``protecting'' meta-level rule
   743 statements.
   744 
   745 * Pure: Logic.(un)varify only works in a global context, which is now
   746 enforced instead of silently assumed.  INCOMPATIBILITY, may use
   747 Logic.legacy_(un)varify as temporary workaround.
   748 
   749 * Pure: structure Name provides scalable operations for generating
   750 internal variable names, notably Name.variants etc.  This replaces
   751 some popular functions from term.ML:
   752 
   753   Term.variant		->  Name.variant
   754   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
   755   Term.invent_names	->  Name.invent_list
   756 
   757 Note that low-level renaming rarely occurs in new code -- operations
   758 from structure Variable are used instead (see below).
   759 
   760 * Pure: structure Variable provides fundamental operations for proper
   761 treatment of fixed/schematic variables in a context.  For example,
   762 Variable.import introduces fixes for schematics of given facts and
   763 Variable.export reverses the effect (up to renaming) -- this replaces
   764 various freeze_thaw operations.
   765 
   766 * Pure: structure Goal provides simple interfaces for
   767 init/conclude/finish and tactical prove operations (replacing former
   768 Tactic.prove).  Goal.prove is the canonical way to prove results
   769 within a given context; Goal.prove_global is a degraded version for
   770 theory level goals, including a global Drule.standard.  Note that
   771 OldGoals.prove_goalw_cterm has long been obsolete, since it is
   772 ill-behaved in a local proof context (e.g. with local fixes/assumes or
   773 in a locale context).
   774 
   775 * Isar: simplified treatment of user-level errors, using exception
   776 ERROR of string uniformly.  Function error now merely raises ERROR,
   777 without any side effect on output channels.  The Isar toplevel takes
   778 care of proper display of ERROR exceptions.  ML code may use plain
   779 handle/can/try; cat_error may be used to concatenate errors like this:
   780 
   781   ... handle ERROR msg => cat_error msg "..."
   782 
   783 Toplevel ML code (run directly or through the Isar toplevel) may be
   784 embedded into the Isar toplevel with exception display/debug like
   785 this:
   786 
   787   Isar.toplevel (fn () => ...)
   788 
   789 INCOMPATIBILITY, removed special transform_error facilities, removed
   790 obsolete variants of user-level exceptions (ERROR_MESSAGE,
   791 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
   792 -- use plain ERROR instead.
   793 
   794 * Isar: theory setup now has type (theory -> theory), instead of a
   795 list.  INCOMPATIBILITY, may use #> to compose setup functions.
   796 
   797 * Isar: installed ML toplevel pretty printer for type Proof.context,
   798 subject to ProofContext.debug/verbose flags.
   799 
   800 * Isar: Toplevel.theory_to_proof admits transactions that modify the
   801 theory before entering a proof state.  Transactions now always see a
   802 quasi-functional intermediate checkpoint, both in interactive and
   803 batch mode.
   804 
   805 * Simplifier: the simpset of a running simplification process now
   806 contains a proof context (cf. Simplifier.the_context), which is the
   807 very context that the initial simpset has been retrieved from (by
   808 simpset_of/local_simpset_of).  Consequently, all plug-in components
   809 (solver, looper etc.) may depend on arbitrary proof data.
   810 
   811 * Simplifier.inherit_context inherits the proof context (plus the
   812 local bounds) of the current simplification process; any simproc
   813 etc. that calls the Simplifier recursively should do this!  Removed
   814 former Simplifier.inherit_bounds, which is already included here --
   815 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
   816 specify an explicit context using Simplifier.context/theory_context.
   817 
   818 * Simplifier/Classical Reasoner: more abstract interfaces
   819 change_simpset/claset for modifying the simpset/claset reference of a
   820 theory; raw versions simpset/claset_ref etc. have been discontinued --
   821 INCOMPATIBILITY.
   822 
   823 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
   824 "Trueprop" etc.
   825 
   826 
   827 
   828 New in Isabelle2005 (October 2005)
   829 ----------------------------------
   830 
   831 *** General ***
   832 
   833 * Theory headers: the new header syntax for Isar theories is
   834 
   835   theory <name>
   836   imports <theory1> ... <theoryN>
   837   uses <file1> ... <fileM>
   838   begin
   839 
   840 where the 'uses' part is optional.  The previous syntax
   841 
   842   theory <name> = <theory1> + ... + <theoryN>:
   843 
   844 will disappear in the next release.  Use isatool fixheaders to convert
   845 existing theory files.  Note that there is no change in ancient
   846 non-Isar theories now, but these will disappear soon.
   847 
   848 * Theory loader: parent theories can now also be referred to via
   849 relative and absolute paths.
   850 
   851 * Command 'find_theorems' searches for a list of criteria instead of a
   852 list of constants. Known criteria are: intro, elim, dest, name:string,
   853 simp:term, and any term. Criteria can be preceded by '-' to select
   854 theorems that do not match. Intro, elim, dest select theorems that
   855 match the current goal, name:s selects theorems whose fully qualified
   856 name contain s, and simp:term selects all simplification rules whose
   857 lhs match term.  Any other term is interpreted as pattern and selects
   858 all theorems matching the pattern. Available in ProofGeneral under
   859 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
   860 
   861   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
   862 
   863 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   864 matching the current goal as introduction rule and not having "HOL."
   865 in their name (i.e. not being defined in theory HOL).
   866 
   867 * Command 'thms_containing' has been discontinued in favour of
   868 'find_theorems'; INCOMPATIBILITY.
   869 
   870 * Communication with Proof General is now 8bit clean, which means that
   871 Unicode text in UTF-8 encoding may be used within theory texts (both
   872 formal and informal parts).  Cf. option -U of the Isabelle Proof
   873 General interface.  Here are some simple examples (cf. src/HOL/ex):
   874 
   875   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
   876   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
   877 
   878 * Improved efficiency of the Simplifier and, to a lesser degree, the
   879 Classical Reasoner.  Typical big applications run around 2 times
   880 faster.
   881 
   882 
   883 *** Document preparation ***
   884 
   885 * Commands 'display_drafts' and 'print_drafts' perform simple output
   886 of raw sources.  Only those symbols that do not require additional
   887 LaTeX packages (depending on comments in isabellesym.sty) are
   888 displayed properly, everything else is left verbatim.  isatool display
   889 and isatool print are used as front ends (these are subject to the
   890 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
   891 
   892 * Command tags control specific markup of certain regions of text,
   893 notably folding and hiding.  Predefined tags include "theory" (for
   894 theory begin and end), "proof" for proof commands, and "ML" for
   895 commands involving ML code; the additional tags "visible" and
   896 "invisible" are unused by default.  Users may give explicit tag
   897 specifications in the text, e.g. ''by %invisible (auto)''.  The
   898 interpretation of tags is determined by the LaTeX job during document
   899 preparation: see option -V of isatool usedir, or options -n and -t of
   900 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
   901 \isadroptag.
   902 
   903 Several document versions may be produced at the same time via isatool
   904 usedir (the generated index.html will link all of them).  Typical
   905 specifications include ''-V document=theory,proof,ML'' to present
   906 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
   907 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
   908 these parts without any formal replacement text.  The Isabelle site
   909 default settings produce ''document'' and ''outline'' versions as
   910 specified above.
   911 
   912 * Several new antiquotations:
   913 
   914   @{term_type term} prints a term with its type annotated;
   915 
   916   @{typeof term} prints the type of a term;
   917 
   918   @{const const} is the same as @{term const}, but checks that the
   919   argument is a known logical constant;
   920 
   921   @{term_style style term} and @{thm_style style thm} print a term or
   922   theorem applying a "style" to it
   923 
   924   @{ML text}
   925 
   926 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
   927 definitions, equations, inequations etc., 'concl' printing only the
   928 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
   929 to print the specified premise.  TermStyle.add_style provides an ML
   930 interface for introducing further styles.  See also the "LaTeX Sugar"
   931 document practical applications.  The ML antiquotation prints
   932 type-checked ML expressions verbatim.
   933 
   934 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
   935 and 'text' support optional locale specification '(in loc)', which
   936 specifies the default context for interpreting antiquotations.  For
   937 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
   938 
   939 * Option 'locale=NAME' of antiquotations specifies an alternative
   940 context interpreting the subsequent argument.  For example: @{thm
   941 [locale=lattice] inf_assoc}.
   942 
   943 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
   944 a proof context.
   945 
   946 * Proper output of antiquotations for theory commands involving a
   947 proof context (such as 'locale' or 'theorem (in loc) ...').
   948 
   949 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
   950 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
   951 
   952 * isatool usedir: new option -C (default true) controls whether option
   953 -D should include a copy of the original document directory; -C false
   954 prevents unwanted effects such as copying of administrative CVS data.
   955 
   956 
   957 *** Pure ***
   958 
   959 * Considerably improved version of 'constdefs' command.  Now performs
   960 automatic type-inference of declared constants; additional support for
   961 local structure declarations (cf. locales and HOL records), see also
   962 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
   963 sequential dependencies of definitions within a single 'constdefs'
   964 section; moreover, the declared name needs to be an identifier.  If
   965 all fails, consider to fall back on 'consts' and 'defs' separately.
   966 
   967 * Improved indexed syntax and implicit structures.  First of all,
   968 indexed syntax provides a notational device for subscripted
   969 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
   970 expressions.  Secondly, in a local context with structure
   971 declarations, number indexes \<^sub>n or the empty index (default
   972 number 1) refer to a certain fixed variable implicitly; option
   973 show_structs controls printing of implicit structures.  Typical
   974 applications of these concepts involve record types and locales.
   975 
   976 * New command 'no_syntax' removes grammar declarations (and
   977 translations) resulting from the given syntax specification, which is
   978 interpreted in the same manner as for the 'syntax' command.
   979 
   980 * 'Advanced' translation functions (parse_translation etc.) may depend
   981 on the signature of the theory context being presently used for
   982 parsing/printing, see also isar-ref manual.
   983 
   984 * Improved 'oracle' command provides a type-safe interface to turn an
   985 ML expression of type theory -> T -> term into a primitive rule of
   986 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
   987 is already included here); see also FOL/ex/IffExample.thy;
   988 INCOMPATIBILITY.
   989 
   990 * axclass: name space prefix for class "c" is now "c_class" (was "c"
   991 before); "cI" is no longer bound, use "c.intro" instead.
   992 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
   993 axclasses vs. locales.
   994 
   995 * Improved internal renaming of symbolic identifiers -- attach primes
   996 instead of base 26 numbers.
   997 
   998 * New flag show_question_marks controls printing of leading question
   999 marks in schematic variable names.
  1000 
  1001 * In schematic variable names, *any* symbol following \<^isub> or
  1002 \<^isup> is now treated as part of the base name.  For example, the
  1003 following works without printing of awkward ".0" indexes:
  1004 
  1005   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1006     by simp
  1007 
  1008 * Inner syntax includes (*(*nested*) comments*).
  1009 
  1010 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1011 annotations as "(00...)".
  1012 
  1013 * Clear separation of logical types and nonterminals, where the latter
  1014 may only occur in 'syntax' specifications or type abbreviations.
  1015 Before that distinction was only partially implemented via type class
  1016 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1017 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1018 exotic syntax specifications may require further adaption
  1019 (e.g. Cube/Cube.thy).
  1020 
  1021 * Removed obsolete type class "logic", use the top sort {} instead.
  1022 Note that non-logical types should be declared as 'nonterminals'
  1023 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1024 specifications.
  1025 
  1026 * Attributes 'induct' and 'cases': type or set names may now be
  1027 locally fixed variables as well.
  1028 
  1029 * Simplifier: can now control the depth to which conditional rewriting
  1030 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1031 Limit.
  1032 
  1033 * Simplifier: simplification procedures may now take the current
  1034 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1035 interface), which is very useful for calling the Simplifier
  1036 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1037 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1038 low-level mk_simproc no longer applies Logic.varify internally, to
  1039 allow for use in a context of fixed variables.
  1040 
  1041 * thin_tac now works even if the assumption being deleted contains !!
  1042 or ==>.  More generally, erule now works even if the major premise of
  1043 the elimination rule contains !! or ==>.
  1044 
  1045 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1046 
  1047 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1048 from Pure, which contains all common declarations already.  Both
  1049 theories are defined via plain Isabelle/Isar .thy files.
  1050 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1051 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1052 use isatool fixcpure to adapt your theory and ML sources.
  1053 
  1054 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1055 selections of theorems in named facts via index ranges.
  1056 
  1057 * 'print_theorems': in theory mode, really print the difference
  1058 wrt. the last state (works for interactive theory development only),
  1059 in proof mode print all local facts (cf. 'print_facts');
  1060 
  1061 * 'hide': option '(open)' hides only base names.
  1062 
  1063 * More efficient treatment of intermediate checkpoints in interactive
  1064 theory development.
  1065 
  1066 * Code generator is now invoked via code_module (incremental code
  1067 generation) and code_library (modular code generation, ML structures
  1068 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1069 must be quoted when used as identifiers.
  1070 
  1071 * New 'value' command for reading, evaluating and printing terms using
  1072 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1073 quoted when used as identifier.
  1074 
  1075 
  1076 *** Locales ***
  1077 
  1078 * New commands for the interpretation of locale expressions in
  1079 theories (1), locales (2) and proof contexts (3).  These generate
  1080 proof obligations from the expression specification.  After the
  1081 obligations have been discharged, theorems of the expression are added
  1082 to the theory, target locale or proof context.  The synopsis of the
  1083 commands is a follows:
  1084 
  1085   (1) interpretation expr inst
  1086   (2) interpretation target < expr
  1087   (3) interpret expr inst
  1088 
  1089 Interpretation in theories and proof contexts require a parameter
  1090 instantiation of terms from the current context.  This is applied to
  1091 specifications and theorems of the interpreted expression.
  1092 Interpretation in locales only permits parameter renaming through the
  1093 locale expression.  Interpretation is smart in that interpretations
  1094 that are active already do not occur in proof obligations, neither are
  1095 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1096 inspect active interpretations of a particular locale.  For details,
  1097 see the Isar Reference manual.  Examples can be found in
  1098 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1099 
  1100 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1101 'interpret' instead.
  1102 
  1103 * New context element 'constrains' for adding type constraints to
  1104 parameters.
  1105 
  1106 * Context expressions: renaming of parameters with syntax
  1107 redeclaration.
  1108 
  1109 * Locale declaration: 'includes' disallowed.
  1110 
  1111 * Proper static binding of attribute syntax -- i.e. types / terms /
  1112 facts mentioned as arguments are always those of the locale definition
  1113 context, independently of the context of later invocations.  Moreover,
  1114 locale operations (renaming and type / term instantiation) are applied
  1115 to attribute arguments as expected.
  1116 
  1117 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1118 actual attributes; rare situations may require Attrib.attribute to
  1119 embed those attributes into Attrib.src that lack concrete syntax.
  1120 Attribute implementations need to cooperate properly with the static
  1121 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1122 Attrib.XXX_thm etc. already do the right thing without further
  1123 intervention.  Only unusual applications -- such as "where" or "of"
  1124 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1125 on the context and the facts involved -- may have to assign parsed
  1126 values to argument tokens explicitly.
  1127 
  1128 * Changed parameter management in theorem generation for long goal
  1129 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1130 theorem statement in rare situations.
  1131 
  1132 * Locale inspection command 'print_locale' omits notes elements.  Use
  1133 'print_locale!' to have them included in the output.
  1134 
  1135 
  1136 *** Provers ***
  1137 
  1138 * Provers/hypsubst.ML: improved version of the subst method, for
  1139 single-step rewriting: it now works in bound variable contexts. New is
  1140 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1141 rewrite a different subterm than the original subst method, which is
  1142 still available as 'simplesubst'.
  1143 
  1144 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1145 and quasi orders.
  1146 
  1147 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1148 reflexive-transitive closure of relations.
  1149 
  1150 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1151 limit (previously hard-coded with a value of 20) user-definable.
  1152 
  1153 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1154 is peformed already.  Object-logics merely need to finish their
  1155 initial simpset configuration as before.  INCOMPATIBILITY.
  1156 
  1157 
  1158 *** HOL ***
  1159 
  1160 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1161 
  1162   syntax (epsilon)
  1163     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1164 
  1165 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1166 and x-symbol; use option '-m epsilon' to get it actually printed.
  1167 Moreover, the mathematically important symbolic identifier \<epsilon>
  1168 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1169 
  1170 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1171 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1172 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1173 support corresponding Isar calculations.
  1174 
  1175 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1176 instead of ":".
  1177 
  1178 * theory SetInterval: changed the syntax for open intervals:
  1179 
  1180   Old       New
  1181   {..n(}    {..<n}
  1182   {)n..}    {n<..}
  1183   {m..n(}   {m..<n}
  1184   {)m..n}   {m<..n}
  1185   {)m..n(}  {m<..<n}
  1186 
  1187 The old syntax is still supported but will disappear in the next
  1188 release.  For conversion use the following Emacs search and replace
  1189 patterns (these are not perfect but work quite well):
  1190 
  1191   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1192   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1193 
  1194 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1195 equalities in commutative rings; method 'algebra' provides a generic
  1196 interface.
  1197 
  1198 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1199 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1200 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1201 be a tuple pattern.
  1202 
  1203 Some new syntax forms are available:
  1204 
  1205   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1206   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1207   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1208   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1209 
  1210 The latter form "\<Sum>x < k. e" used to be based on a separate
  1211 function "Summation", which has been discontinued.
  1212 
  1213 * theory Finite_Set: in structured induction proofs, the insert case
  1214 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1215 (insert F x)'.
  1216 
  1217 * The 'refute' command has been extended to support a much larger
  1218 fragment of HOL, including axiomatic type classes, constdefs and
  1219 typedefs, inductive datatypes and recursion.
  1220 
  1221 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1222 Requires zChaff with proof generation to be installed.  See
  1223 HOL/ex/SAT_Examples.thy for examples.
  1224 
  1225 * Datatype induction via method 'induct' now preserves the name of the
  1226 induction variable. For example, when proving P(xs::'a list) by
  1227 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1228 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1229 in unstructured proof scripts.
  1230 
  1231 * Reworked implementation of records.  Improved scalability for
  1232 records with many fields, avoiding performance problems for type
  1233 inference. Records are no longer composed of nested field types, but
  1234 of nested extension types. Therefore the record type only grows linear
  1235 in the number of extensions and not in the number of fields.  The
  1236 top-level (users) view on records is preserved.  Potential
  1237 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1238 old record representation. The type generated for a record is called
  1239 <record_name>_ext_type.
  1240 
  1241 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1242 proofs triggered by a record definition or a simproc (if
  1243 quick_and_dirty is enabled).  Definitions of large records can take
  1244 quite long.
  1245 
  1246 New simproc record_upd_simproc for simplification of multiple record
  1247 updates enabled by default.  Moreover, trivial updates are also
  1248 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1249 occasionally, since simplification is more powerful by default.
  1250 
  1251 * typedef: proper support for polymorphic sets, which contain extra
  1252 type-variables in the term.
  1253 
  1254 * Simplifier: automatically reasons about transitivity chains
  1255 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1256 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1257 old proofs break occasionally as simplification may now solve more
  1258 goals than previously.
  1259 
  1260 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1261 present.  Works for all partial orders (class "order"), in particular
  1262 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1263 just like y <= x.
  1264 
  1265 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1266 bound variable or a constant then the let is unfolded.  Otherwise
  1267 first a is simplified to b, and then f b is simplified to g. If
  1268 possible we abstract b from g arriving at "let x = b in h x",
  1269 otherwise we unfold the let and arrive at g.  The simproc can be
  1270 enabled/disabled by the reference use_let_simproc.  Potential
  1271 INCOMPATIBILITY since simplification is more powerful by default.
  1272 
  1273 * Classical reasoning: the meson method now accepts theorems as arguments.
  1274 
  1275 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1276 jobs to provide advice on the provability of subgoals.
  1277 
  1278 * Theory OrderedGroup and Ring_and_Field: various additions and
  1279 improvements to faciliate calculations involving equalities and
  1280 inequalities.
  1281 
  1282 The following theorems have been eliminated or modified
  1283 (INCOMPATIBILITY):
  1284 
  1285   abs_eq             now named abs_of_nonneg
  1286   abs_of_ge_0        now named abs_of_nonneg
  1287   abs_minus_eq       now named abs_of_nonpos
  1288   imp_abs_id         now named abs_of_nonneg
  1289   imp_abs_neg_id     now named abs_of_nonpos
  1290   mult_pos           now named mult_pos_pos
  1291   mult_pos_le        now named mult_nonneg_nonneg
  1292   mult_pos_neg_le    now named mult_nonneg_nonpos
  1293   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1294   mult_neg           now named mult_neg_neg
  1295   mult_neg_le        now named mult_nonpos_nonpos
  1296 
  1297 * Theory Parity: added rules for simplifying exponents.
  1298 
  1299 * Theory List:
  1300 
  1301 The following theorems have been eliminated or modified
  1302 (INCOMPATIBILITY):
  1303 
  1304   list_all_Nil       now named list_all.simps(1)
  1305   list_all_Cons      now named list_all.simps(2)
  1306   list_all_conv      now named list_all_iff
  1307   set_mem_eq         now named mem_iff
  1308 
  1309 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1310 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1311 
  1312 
  1313 *** HOL-Complex ***
  1314 
  1315 * Theory RealDef: better support for embedding natural numbers and
  1316 integers in the reals.
  1317 
  1318 The following theorems have been eliminated or modified
  1319 (INCOMPATIBILITY):
  1320 
  1321   exp_ge_add_one_self  now requires no hypotheses
  1322   real_of_int_add      reversed direction of equality (use [symmetric])
  1323   real_of_int_minus    reversed direction of equality (use [symmetric])
  1324   real_of_int_diff     reversed direction of equality (use [symmetric])
  1325   real_of_int_mult     reversed direction of equality (use [symmetric])
  1326 
  1327 * Theory RComplete: expanded support for floor and ceiling functions.
  1328 
  1329 * Theory Ln is new, with properties of the natural logarithm
  1330 
  1331 * Hyperreal: There is a new type constructor "star" for making
  1332 nonstandard types.  The old type names are now type synonyms:
  1333 
  1334   hypreal = real star
  1335   hypnat = nat star
  1336   hcomplex = complex star
  1337 
  1338 * Hyperreal: Many groups of similarly-defined constants have been
  1339 replaced by polymorphic versions (INCOMPATIBILITY):
  1340 
  1341   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1342 
  1343   starset      <-- starsetNat, starsetC
  1344   *s*          <-- *sNat*, *sc*
  1345   starset_n    <-- starsetNat_n, starsetC_n
  1346   *sn*         <-- *sNatn*, *scn*
  1347   InternalSets <-- InternalNatSets, InternalCSets
  1348 
  1349   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1350   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1351   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1352   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1353   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1354 
  1355 * Hyperreal: Many type-specific theorems have been removed in favor of
  1356 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1357 
  1358   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1359   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1360   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1361   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1362   right_minus <-- hypreal_add_minus
  1363   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1364   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1365   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1366   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1367   mult_1_right <-- hcomplex_mult_one_right
  1368   mult_zero_left <-- hcomplex_mult_zero_left
  1369   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1370   right_distrib <-- hypnat_add_mult_distrib2
  1371   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1372   right_inverse <-- hypreal_mult_inverse
  1373   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1374   order_refl <-- {hypreal,hypnat}_le_refl
  1375   order_trans <-- {hypreal,hypnat}_le_trans
  1376   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1377   order_less_le <-- {hypreal,hypnat}_less_le
  1378   linorder_linear <-- {hypreal,hypnat}_le_linear
  1379   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1380   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1381   add_nonneg_nonneg <-- hypreal_le_add_order
  1382 
  1383 * Hyperreal: Separate theorems having to do with type-specific
  1384 versions of constants have been merged into theorems that apply to the
  1385 new polymorphic constants (INCOMPATIBILITY):
  1386 
  1387   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1388   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1389   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1390   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1391   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1392   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1393   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1394   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1395   STAR_diff <-- {STAR,STARC}_diff
  1396   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1397     STARC_hcomplex_of_complex}_image_subset
  1398   starset_n_Un <-- starset{Nat,C}_n_Un
  1399   starset_n_Int <-- starset{Nat,C}_n_Int
  1400   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1401   starset_n_diff <-- starset{Nat,C}_n_diff
  1402   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1403   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1404   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1405   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1406   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1407   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1408   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1409   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1410   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1411   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1412   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1413   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1414   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1415   starfun_diff <-- starfun{C,RC,CR}_diff
  1416   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1417   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1418   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1419   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1420   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1421   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1422   starfun_Id <-- starfunC_Id
  1423   starfun_approx <-- starfun{Nat,CR}_approx
  1424   starfun_capprox <-- starfun{C,RC}_capprox
  1425   starfun_abs <-- starfunNat_rabs
  1426   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1427   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1428   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1429   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1430   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1431   starfun_add_approx <-- starfunCR_add_approx
  1432   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1433   starfun_divide <-- starfun{C,CR,RC}_divide
  1434   starfun_n <-- starfun{Nat,C}_n
  1435   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1436   starfun_n_add <-- starfun{Nat,C}_n_add
  1437   starfun_n_add_minus <-- starfunNat_n_add_minus
  1438   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1439   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1440   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1441 
  1442   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1443   star_n_minus <-- {hypreal,hcomplex}_minus
  1444   star_n_diff <-- {hypreal,hcomplex}_diff
  1445   star_n_mult <-- {hypreal,hcomplex}_mult
  1446   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1447   star_n_le <-- {hypreal,hypnat}_le
  1448   star_n_less <-- {hypreal,hypnat}_less
  1449   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1450   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1451   star_n_abs <-- hypreal_hrabs
  1452   star_n_divide <-- hcomplex_divide
  1453 
  1454   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1455   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1456   star_of_diff <-- hypreal_of_real_diff
  1457   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1458   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1459   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1460   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1461   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1462   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1463   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1464   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1465   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1466   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1467   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1468   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1469   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1470   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1471   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1472   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1473   star_of_power <-- hypreal_of_real_power
  1474   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1475 
  1476 * Hyperreal: new method "transfer" that implements the transfer
  1477 principle of nonstandard analysis. With a subgoal that mentions
  1478 nonstandard types like "'a star", the command "apply transfer"
  1479 replaces it with an equivalent one that mentions only standard types.
  1480 To be successful, all free variables must have standard types; non-
  1481 standard variables must have explicit universal quantifiers.
  1482 
  1483 * Hyperreal: A theory of Taylor series.
  1484 
  1485 
  1486 *** HOLCF ***
  1487 
  1488 * Discontinued special version of 'constdefs' (which used to support
  1489 continuous functions) in favor of the general Pure one with full
  1490 type-inference.
  1491 
  1492 * New simplification procedure for solving continuity conditions; it
  1493 is much faster on terms with many nested lambda abstractions (cubic
  1494 instead of exponential time).
  1495 
  1496 * New syntax for domain package: selector names are now optional.
  1497 Parentheses should be omitted unless argument is lazy, for example:
  1498 
  1499   domain 'a stream = cons "'a" (lazy "'a stream")
  1500 
  1501 * New command 'fixrec' for defining recursive functions with pattern
  1502 matching; defining multiple functions with mutual recursion is also
  1503 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1504 sinr, or any data constructor defined by the domain package. The given
  1505 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1506 syntax and examples.
  1507 
  1508 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1509 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1510 but the proof obligation additionally includes an admissibility
  1511 requirement. The packages generate instances of class cpo or pcpo,
  1512 with continuity and strictness theorems for Rep and Abs.
  1513 
  1514 * HOLCF: Many theorems have been renamed according to a more standard naming
  1515 scheme (INCOMPATIBILITY):
  1516 
  1517   foo_inject:  "foo$x = foo$y ==> x = y"
  1518   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1519   foo_less:    "(foo$x << foo$y) = (x << y)"
  1520   foo_strict:  "foo$UU = UU"
  1521   foo_defined: "... ==> foo$x ~= UU"
  1522   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1523 
  1524 
  1525 *** ZF ***
  1526 
  1527 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1528 including the First Isomorphism Theorem (on quotienting by the kernel
  1529 of a homomorphism).
  1530 
  1531 * ZF/Simplifier: install second copy of type solver that actually
  1532 makes use of TC rules declared to Isar proof contexts (or locales);
  1533 the old version is still required for ML proof scripts.
  1534 
  1535 
  1536 *** Cube ***
  1537 
  1538 * Converted to Isar theory format; use locales instead of axiomatic
  1539 theories.
  1540 
  1541 
  1542 *** ML ***
  1543 
  1544 * Pure/library.ML no longer defines its own option datatype, but uses
  1545 that of the SML basis, which has constructors NONE and SOME instead of
  1546 None and Some, as well as exception Option.Option instead of OPTION.
  1547 The functions the, if_none, is_some, is_none have been adapted
  1548 accordingly, while Option.map replaces apsome.
  1549 
  1550 * Pure/library.ML: the exception LIST has been given up in favour of
  1551 the standard exceptions Empty and Subscript, as well as
  1552 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1553 superceded by the standard hd and tl functions etc.
  1554 
  1555 A number of basic list functions are no longer exported to the ML
  1556 toplevel, as they are variants of predefined functions.  The following
  1557 suggests how one can translate existing code:
  1558 
  1559     rev_append xs ys = List.revAppend (xs, ys)
  1560     nth_elem (i, xs) = List.nth (xs, i)
  1561     last_elem xs = List.last xs
  1562     flat xss = List.concat xss
  1563     seq fs = List.app fs
  1564     partition P xs = List.partition P xs
  1565     mapfilter f xs = List.mapPartial f xs
  1566 
  1567 * Pure/library.ML: several combinators for linear functional
  1568 transformations, notably reverse application and composition:
  1569 
  1570   x |> f                f #> g
  1571   (x, y) |-> f          f #-> g
  1572 
  1573 * Pure/library.ML: introduced/changed precedence of infix operators:
  1574 
  1575   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1576   infix 2 ?;
  1577   infix 3 o oo ooo oooo;
  1578   infix 4 ~~ upto downto;
  1579 
  1580 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1581 infix operators.
  1582 
  1583 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1584 fold_map support linear functional transformations and nesting.  For
  1585 example:
  1586 
  1587   fold f [x1, ..., xN] y =
  1588     y |> f x1 |> ... |> f xN
  1589 
  1590   (fold o fold) f [xs1, ..., xsN] y =
  1591     y |> fold f xs1 |> ... |> fold f xsN
  1592 
  1593   fold f [x1, ..., xN] =
  1594     f x1 #> ... #> f xN
  1595 
  1596   (fold o fold) f [xs1, ..., xsN] =
  1597     fold f xs1 #> ... #> fold f xsN
  1598 
  1599 * Pure/library.ML: the following selectors on type 'a option are
  1600 available:
  1601 
  1602   the:               'a option -> 'a  (*partial*)
  1603   these:             'a option -> 'a  where 'a = 'b list
  1604   the_default: 'a -> 'a option -> 'a
  1605   the_list:          'a option -> 'a list
  1606 
  1607 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1608 basic operations for association lists, following natural argument
  1609 order; moreover the explicit equality predicate passed here avoids
  1610 potentially expensive polymorphic runtime equality checks.
  1611 The old functions may be expressed as follows:
  1612 
  1613   assoc = uncurry (AList.lookup (op =))
  1614   assocs = these oo AList.lookup (op =)
  1615   overwrite = uncurry (AList.update (op =)) o swap
  1616 
  1617 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1618 
  1619   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1620   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1621 
  1622 replacing make_keylist and keyfilter (occassionally used)
  1623 Naive rewrites:
  1624 
  1625   make_keylist = AList.make
  1626   keyfilter = AList.find (op =)
  1627 
  1628 * eq_fst and eq_snd now take explicit equality parameter, thus
  1629   avoiding eqtypes. Naive rewrites:
  1630 
  1631     eq_fst = eq_fst (op =)
  1632     eq_snd = eq_snd (op =)
  1633 
  1634 * Removed deprecated apl and apr (rarely used).
  1635   Naive rewrites:
  1636 
  1637     apl (n, op) =>>= curry op n
  1638     apr (op, m) =>>= fn n => op (n, m)
  1639 
  1640 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1641 provides a reasonably efficient light-weight implementation of sets as
  1642 lists.
  1643 
  1644 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1645 few new operations; existing lookup and update are now curried to
  1646 follow natural argument order (for use with fold etc.);
  1647 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1648 
  1649 * Pure/General: output via the Isabelle channels of
  1650 writeln/warning/error etc. is now passed through Output.output, with a
  1651 hook for arbitrary transformations depending on the print_mode
  1652 (cf. Output.add_mode -- the first active mode that provides a output
  1653 function wins).  Already formatted output may be embedded into further
  1654 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1655 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1656 accommodate easy composition of diagnostic messages etc.  Programmers
  1657 rarely need to care about Output.output or Output.raw at all, with
  1658 some notable exceptions: Output.output is required when bypassing the
  1659 standard channels (writeln etc.), or in token translations to produce
  1660 properly formatted results; Output.raw is required when capturing
  1661 already output material that will eventually be presented to the user
  1662 a second time.  For the default print mode, both Output.output and
  1663 Output.raw have no effect.
  1664 
  1665 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1666 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1667 cumulative results are displayed at the end of a batch session.
  1668 
  1669 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1670 replaced by File.platform_path and File.shell_path (with appropriate
  1671 hooks).  This provides a clean interface for unusual systems where the
  1672 internal and external process view of file names are different.
  1673 
  1674 * Pure: more efficient orders for basic syntactic entities: added
  1675 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1676 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1677 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1678 orders now -- potential INCOMPATIBILITY for code that depends on a
  1679 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1680 Library.sort_strings on result).
  1681 
  1682 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1683 fold_types traverse types/terms from left to right, observing natural
  1684 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1685 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1686 
  1687 * Pure: name spaces have been refined, with significant changes of the
  1688 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1689 to extern(_table).  The plain name entry path is superceded by a
  1690 general 'naming' context, which also includes the 'policy' to produce
  1691 a fully qualified name and external accesses of a fully qualified
  1692 name; NameSpace.extend is superceded by context dependent
  1693 Sign.declare_name.  Several theory and proof context operations modify
  1694 the naming context.  Especially note Theory.restore_naming and
  1695 ProofContext.restore_naming to get back to a sane state; note that
  1696 Theory.add_path is no longer sufficient to recover from
  1697 Theory.absolute_path in particular.
  1698 
  1699 * Pure: new flags short_names (default false) and unique_names
  1700 (default true) for controlling output of qualified names.  If
  1701 short_names is set, names are printed unqualified.  If unique_names is
  1702 reset, the name prefix is reduced to the minimum required to achieve
  1703 the original result when interning again, even if there is an overlap
  1704 with earlier declarations.
  1705 
  1706 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1707 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1708 (useful for printing error messages).  INCOMPATIBILITY.
  1709 
  1710 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1711 Theory.theory are now identified, referring to the universal
  1712 Context.theory (see Pure/context.ML).  Actual signature and theory
  1713 content is managed as theory data.  The old code and interfaces were
  1714 spread over many files and structures; the new arrangement introduces
  1715 considerable INCOMPATIBILITY to gain more clarity:
  1716 
  1717   Context -- theory management operations (name, identity, inclusion,
  1718     parents, ancestors, merge, etc.), plus generic theory data;
  1719 
  1720   Sign -- logical signature and syntax operations (declaring consts,
  1721     types, etc.), plus certify/read for common entities;
  1722 
  1723   Theory -- logical theory operations (stating axioms, definitions,
  1724     oracles), plus a copy of logical signature operations (consts,
  1725     types, etc.); also a few basic management operations (Theory.copy,
  1726     Theory.merge, etc.)
  1727 
  1728 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  1729 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  1730 for convenience -- they merely return the theory.
  1731 
  1732 * Pure: type Type.tsig is superceded by theory in most interfaces.
  1733 
  1734 * Pure: the Isar proof context type is already defined early in Pure
  1735 as Context.proof (note that ProofContext.context and Proof.context are
  1736 aliases, where the latter is the preferred name).  This enables other
  1737 Isabelle components to refer to that type even before Isar is present.
  1738 
  1739 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  1740 typeK, constK, axiomK, oracleK), but provide explicit operations for
  1741 any of these kinds.  For example, Sign.intern typeK is now
  1742 Sign.intern_type, Theory.hide_space Sign.typeK is now
  1743 Theory.hide_types.  Also note that former
  1744 Theory.hide_classes/types/consts are now
  1745 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  1746 internalize their arguments!  INCOMPATIBILITY.
  1747 
  1748 * Pure: get_thm interface (of PureThy and ProofContext) expects
  1749 datatype thmref (with constructors Name and NameSelection) instead of
  1750 plain string -- INCOMPATIBILITY;
  1751 
  1752 * Pure: cases produced by proof methods specify options, where NONE
  1753 means to remove case bindings -- INCOMPATIBILITY in
  1754 (RAW_)METHOD_CASES.
  1755 
  1756 * Pure: the following operations retrieve axioms or theorems from a
  1757 theory node or theory hierarchy, respectively:
  1758 
  1759   Theory.axioms_of: theory -> (string * term) list
  1760   Theory.all_axioms_of: theory -> (string * term) list
  1761   PureThy.thms_of: theory -> (string * thm) list
  1762   PureThy.all_thms_of: theory -> (string * thm) list
  1763 
  1764 * Pure: print_tac now outputs the goal through the trace channel.
  1765 
  1766 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  1767 Reference Toplevel.debug (default false) controls detailed printing
  1768 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  1769 controls execution profiling -- set to 1 for time and 2 for space
  1770 (both increase the runtime).
  1771 
  1772 * Isar session: The initial use of ROOT.ML is now always timed,
  1773 i.e. the log will show the actual process times, in contrast to the
  1774 elapsed wall-clock time that the outer shell wrapper produces.
  1775 
  1776 * Simplifier: improved handling of bound variables (nameless
  1777 representation, avoid allocating new strings).  Simprocs that invoke
  1778 the Simplifier recursively should use Simplifier.inherit_bounds to
  1779 avoid local name clashes.  Failure to do so produces warnings
  1780 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  1781 for further details.
  1782 
  1783 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  1784 bindings for all theorems stored within a given theory; this may help
  1785 in porting non-Isar theories to Isar ones, while keeping ML proof
  1786 scripts for the time being.
  1787 
  1788 * ML operator HTML.with_charset specifies the charset begin used for
  1789 generated HTML files.  For example:
  1790 
  1791   HTML.with_charset "utf-8" use_thy "Hebrew";
  1792   HTML.with_charset "utf-8" use_thy "Chinese";
  1793 
  1794 
  1795 *** System ***
  1796 
  1797 * Allow symlinks to all proper Isabelle executables (Isabelle,
  1798 isabelle, isatool etc.).
  1799 
  1800 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  1801 isatool doc, isatool mkdir, display_drafts etc.).
  1802 
  1803 * isatool usedir: option -f allows specification of the ML file to be
  1804 used by Isabelle; default is ROOT.ML.
  1805 
  1806 * New isatool version outputs the version identifier of the Isabelle
  1807 distribution being used.
  1808 
  1809 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1810 (containing Boolean satisfiability problems) into Isabelle/HOL
  1811 theories.
  1812 
  1813 
  1814 
  1815 New in Isabelle2004 (April 2004)
  1816 --------------------------------
  1817 
  1818 *** General ***
  1819 
  1820 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1821   Replaces linorder.ML.
  1822 
  1823 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1824   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1825   (\<a>...\<z>), are now considered normal letters, and can therefore
  1826   be used anywhere where an ASCII letter (a...zA...Z) has until
  1827   now. COMPATIBILITY: This obviously changes the parsing of some
  1828   terms, especially where a symbol has been used as a binder, say
  1829   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1830   as an identifier.  Fix it by inserting a space around former
  1831   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1832   existing theory and ML files.
  1833 
  1834 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  1835 
  1836 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  1837   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  1838   a normal (but invisible) letter. For multiple letter subscripts repeat
  1839   \<^isub> like this: x\<^isub>1\<^isub>2.
  1840 
  1841 * Pure: There are now sub-/superscripts that can span more than one
  1842   character. Text between \<^bsub> and \<^esub> is set in subscript in
  1843   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  1844   superscript. The new control characters are not identifier parts.
  1845 
  1846 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  1847   content of "..." to the latex file instead of \isacntrl... . The "..."
  1848   may consist of any printable characters excluding the end bracket >.
  1849 
  1850 * Pure: Using new Isar command "finalconsts" (or the ML functions
  1851   Theory.add_finals or Theory.add_finals_i) it is now possible to
  1852   declare constants "final", which prevents their being given a definition
  1853   later.  It is useful for constants whose behaviour is fixed axiomatically
  1854   rather than definitionally, such as the meta-logic connectives.
  1855 
  1856 * Pure: 'instance' now handles general arities with general sorts
  1857   (i.e. intersections of classes),
  1858 
  1859 * Presentation: generated HTML now uses a CSS style sheet to make layout
  1860   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  1861   It can be changed to alter the colors/layout of generated pages.
  1862 
  1863 
  1864 *** Isar ***
  1865 
  1866 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  1867   cut_tac, subgoal_tac and thin_tac:
  1868   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  1869     locales are no longer forced to write Isar proof scripts.
  1870     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  1871     emulations.
  1872   - INCOMPATIBILITY: names of variables to be instantiated may no
  1873     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  1874     This is consistent with the instantiation attribute "where".
  1875 
  1876 * Attributes "where" and "of":
  1877   - Now take type variables of instantiated theorem into account when reading
  1878     the instantiation string.  This fixes a bug that caused instantiated
  1879     theorems to have too special types in some circumstances.
  1880   - "where" permits explicit instantiations of type variables.
  1881 
  1882 * Calculation commands "moreover" and "also" no longer interfere with
  1883   current facts ("this"), admitting arbitrary combinations with "then"
  1884   and derived forms.
  1885 
  1886 * Locales:
  1887   - Goal statements involving the context element "includes" no longer
  1888     generate theorems with internal delta predicates (those ending on
  1889     "_axioms") in the premise.
  1890     Resolve particular premise with <locale>.intro to obtain old form.
  1891   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  1892     specification and "includes" elements in goal statement.
  1893   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  1894     [intro?] and [elim?] (respectively) by default.
  1895   - Experimental command for instantiation of locales in proof contexts:
  1896         instantiate <label>[<attrs>]: <loc>
  1897     Instantiates locale <loc> and adds all its theorems to the current context
  1898     taking into account their attributes.  Label and attrs are optional
  1899     modifiers, like in theorem declarations.  If present, names of
  1900     instantiated theorems are qualified with <label>, and the attributes
  1901     <attrs> are applied after any attributes these theorems might have already.
  1902       If the locale has assumptions, a chained fact of the form
  1903     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  1904     are derived.  The command does not support old-style locales declared
  1905     with "locale (open)".
  1906       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  1907 
  1908 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  1909   (Isar) contexts.
  1910 
  1911 
  1912 *** HOL ***
  1913 
  1914 * Proof import: new image HOL4 contains the imported library from
  1915   the HOL4 system with about 2500 theorems. It is imported by
  1916   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  1917   can be used like any other Isabelle image.  See
  1918   HOL/Import/HOL/README for more information.
  1919 
  1920 * Simplifier:
  1921   - Much improved handling of linear and partial orders.
  1922     Reasoners for linear and partial orders are set up for type classes
  1923     "linorder" and "order" respectively, and are added to the default simpset
  1924     as solvers.  This means that the simplifier can build transitivity chains
  1925     to solve goals from the assumptions.
  1926   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  1927     of blast or auto after simplification become unnecessary because the goal
  1928     is solved by simplification already.
  1929 
  1930 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  1931     all proved in axiomatic type classes for semirings, rings and fields.
  1932 
  1933 * Numerics:
  1934   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  1935     now formalized using the Ring_and_Field theory mentioned above.
  1936   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  1937     than before, because now they are set up once in a generic manner.
  1938   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  1939     Look for the general versions in Ring_and_Field (and Power if they concern
  1940     exponentiation).
  1941 
  1942 * Type "rat" of the rational numbers is now available in HOL-Complex.
  1943 
  1944 * Records:
  1945   - Record types are now by default printed with their type abbreviation
  1946     instead of the list of all field types. This can be configured via
  1947     the reference "print_record_type_abbr".
  1948   - Simproc "record_upd_simproc" for simplification of multiple updates added
  1949     (not enabled by default).
  1950   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  1951     EX x. x = sel r to True (not enabled by default).
  1952   - Tactic "record_split_simp_tac" to split and simplify records added.
  1953 
  1954 * 'specification' command added, allowing for definition by
  1955   specification.  There is also an 'ax_specification' command that
  1956   introduces the new constants axiomatically.
  1957 
  1958 * arith(_tac) is now able to generate counterexamples for reals as well.
  1959 
  1960 * HOL-Algebra: new locale "ring" for non-commutative rings.
  1961 
  1962 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  1963   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  1964 
  1965 * HOL-Matrix: a first theory for matrices in HOL with an application of
  1966   matrix theory to linear programming.
  1967 
  1968 * Unions and Intersections:
  1969   The latex output syntax of UN and INT has been changed
  1970   from "\Union x \in A. B" to "\Union_{x \in A} B"
  1971   i.e. the index formulae has become a subscript.
  1972   Similarly for "\Union x. B", and for \Inter instead of \Union.
  1973 
  1974 * Unions and Intersections over Intervals:
  1975   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  1976   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  1977   like in normal math, and corresponding versions for < and for intersection.
  1978 
  1979 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  1980   lexicographic dictonary ordering has been added as "lexord".
  1981 
  1982 * ML: the legacy theory structures Int and List have been removed. They had
  1983   conflicted with ML Basis Library structures having the same names.
  1984 
  1985 * 'refute' command added to search for (finite) countermodels.  Only works
  1986   for a fragment of HOL.  The installation of an external SAT solver is
  1987   highly recommended.  See "HOL/Refute.thy" for details.
  1988 
  1989 * 'quickcheck' command: Allows to find counterexamples by evaluating
  1990   formulae under an assignment of free variables to random values.
  1991   In contrast to 'refute', it can deal with inductive datatypes,
  1992   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  1993   for examples.
  1994 
  1995 
  1996 *** HOLCF ***
  1997 
  1998 * Streams now come with concatenation and are part of the HOLCF image
  1999 
  2000 
  2001 
  2002 New in Isabelle2003 (May 2003)
  2003 ------------------------------
  2004 
  2005 *** General ***
  2006 
  2007 * Provers/simplifier:
  2008 
  2009   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2010     Assumptions are now subject to complete mutual simplification,
  2011     not just from left to right. The simplifier now preserves
  2012     the order of assumptions.
  2013 
  2014     Potential INCOMPATIBILITY:
  2015 
  2016     -- simp sometimes diverges where the old version did
  2017        not, e.g. invoking simp on the goal
  2018 
  2019         [| P (f x); y = x; f x = f y |] ==> Q
  2020 
  2021        now gives rise to the infinite reduction sequence
  2022 
  2023         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2024 
  2025        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2026        kind of problem.
  2027 
  2028     -- Tactics combining classical reasoner and simplification (such as auto)
  2029        are also affected by this change, because many of them rely on
  2030        simp. They may sometimes diverge as well or yield a different numbers
  2031        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2032        in case of problems. Sometimes subsequent calls to the classical
  2033        reasoner will fail because a preceeding call to the simplifier too
  2034        eagerly simplified the goal, e.g. deleted redundant premises.
  2035 
  2036   - The simplifier trace now shows the names of the applied rewrite rules
  2037 
  2038   - You can limit the number of recursive invocations of the simplifier
  2039     during conditional rewriting (where the simplifie tries to solve the
  2040     conditions before applying the rewrite rule):
  2041     ML "simp_depth_limit := n"
  2042     where n is an integer. Thus you can force termination where previously
  2043     the simplifier would diverge.
  2044 
  2045   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2046 
  2047   - No longer aborts on failed congruence proof.  Instead, the
  2048     congruence is ignored.
  2049 
  2050 * Pure: New generic framework for extracting programs from constructive
  2051   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2052   as HOL/Extraction for some case studies.
  2053 
  2054 * Pure: The main goal of the proof state is no longer shown by default, only
  2055 the subgoals. This behaviour is controlled by a new flag.
  2056    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2057 (ML: Proof.show_main_goal).
  2058 
  2059 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2060 rules whose conclusion matches subgoal 1:
  2061       PG menu: Isabelle/Isar -> Show me -> matching rules
  2062 The rules are ordered by how closely they match the subgoal.
  2063 In particular, rules that solve a subgoal outright are displayed first
  2064 (or rather last, the way they are printed).
  2065 (ML: ProofGeneral.print_intros())
  2066 
  2067 * Pure: New flag trace_unify_fail causes unification to print
  2068 diagnostic information (PG: in trace buffer) when it fails. This is
  2069 useful for figuring out why single step proofs like rule, erule or
  2070 assumption failed.
  2071 
  2072 * Pure: Locale specifications now produce predicate definitions
  2073 according to the body of text (covering assumptions modulo local
  2074 definitions); predicate "loc_axioms" covers newly introduced text,
  2075 while "loc" is cumulative wrt. all included locale expressions; the
  2076 latter view is presented only on export into the global theory
  2077 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2078 on the old view without predicates;
  2079 
  2080 * Pure: predefined locales "var" and "struct" are useful for sharing
  2081 parameters (as in CASL, for example); just specify something like
  2082 ``var x + var y + struct M'' as import;
  2083 
  2084 * Pure: improved thms_containing: proper indexing of facts instead of
  2085 raw theorems; check validity of results wrt. current name space;
  2086 include local facts of proof configuration (also covers active
  2087 locales), cover fixed variables in index; may use "_" in term
  2088 specification; an optional limit for the number of printed facts may
  2089 be given (the default is 40);
  2090 
  2091 * Pure: disallow duplicate fact bindings within new-style theory files
  2092 (batch-mode only);
  2093 
  2094 * Provers: improved induct method: assumptions introduced by case
  2095 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2096 the goal statement); "foo" still refers to all facts collectively;
  2097 
  2098 * Provers: the function blast.overloaded has been removed: all constants
  2099 are regarded as potentially overloaded, which improves robustness in exchange
  2100 for slight decrease in efficiency;
  2101 
  2102 * Provers/linorder: New generic prover for transitivity reasoning over
  2103 linear orders.  Note: this prover is not efficient!
  2104 
  2105 * Isar: preview of problems to finish 'show' now produce an error
  2106 rather than just a warning (in interactive mode);
  2107 
  2108 
  2109 *** HOL ***
  2110 
  2111 * arith(_tac)
  2112 
  2113  - Produces a counter example if it cannot prove a goal.
  2114    Note that the counter example may be spurious if the goal is not a formula
  2115    of quantifier-free linear arithmetic.
  2116    In ProofGeneral the counter example appears in the trace buffer.
  2117 
  2118  - Knows about div k and mod k where k is a numeral of type nat or int.
  2119 
  2120  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2121    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2122    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2123 
  2124 * simp's arithmetic capabilities have been enhanced a bit: it now
  2125 takes ~= in premises into account (by performing a case split);
  2126 
  2127 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2128 are distributed over a sum of terms;
  2129 
  2130 * New tactic "trans_tac" and method "trans" instantiate
  2131 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2132 "<=", "<" and "=").
  2133 
  2134 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2135 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2136 
  2137 * 'typedef' command has new option "open" to suppress the set
  2138 definition;
  2139 
  2140 * functions Min and Max on finite sets have been introduced (theory
  2141 Finite_Set);
  2142 
  2143 * attribute [symmetric] now works for relations as well; it turns
  2144 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2145 
  2146 * induct over a !!-quantified statement (say !!x1..xn):
  2147   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2148 
  2149 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2150 %x. None. Warning: empty_def now refers to the previously hidden definition
  2151 of the empty set.
  2152 
  2153 * Algebra: formalization of classical algebra.  Intended as base for
  2154 any algebraic development in Isabelle.  Currently covers group theory
  2155 (up to Sylow's theorem) and ring theory (Universal Property of
  2156 Univariate Polynomials).  Contributions welcome;
  2157 
  2158 * GroupTheory: deleted, since its material has been moved to Algebra;
  2159 
  2160 * Complex: new directory of the complex numbers with numeric constants,
  2161 nonstandard complex numbers, and some complex analysis, standard and
  2162 nonstandard (Jacques Fleuriot);
  2163 
  2164 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2165 
  2166 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2167 Fleuriot);
  2168 
  2169 * Real/HahnBanach: updated and adapted to locales;
  2170 
  2171 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2172 Gray and Kramer);
  2173 
  2174 * UNITY: added the Meier-Sanders theory of progress sets;
  2175 
  2176 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2177 as abstract algorithms, instantiated to the JVM;
  2178 
  2179 * Bali: Java source language formalization. Type system, operational
  2180 semantics, axiomatic semantics. Supported language features:
  2181 classes, interfaces, objects,virtual methods, static methods,
  2182 static/instance fields, arrays, access modifiers, definite
  2183 assignment, exceptions.
  2184 
  2185 
  2186 *** ZF ***
  2187 
  2188 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2189 universe, etc.);
  2190 
  2191 * Main ZF: virtually all theories converted to new-style format;
  2192 
  2193 
  2194 *** ML ***
  2195 
  2196 * Pure: Tactic.prove provides sane interface for internal proofs;
  2197 omits the infamous "standard" operation, so this is more appropriate
  2198 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2199 
  2200 * Pure: improved error reporting of simprocs;
  2201 
  2202 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2203 up simprocs;
  2204 
  2205 
  2206 *** Document preparation ***
  2207 
  2208 * uses \par instead of \\ for line breaks in theory text. This may
  2209 shift some page breaks in large documents. To get the old behaviour
  2210 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2211 
  2212 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2213 other packages
  2214 
  2215 * \<euro> now needs package babel/greek instead of marvosym (which
  2216 broke \Rightarrow)
  2217 
  2218 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2219 textcomp package)
  2220 
  2221 
  2222 
  2223 New in Isabelle2002 (March 2002)
  2224 --------------------------------
  2225 
  2226 *** Document preparation ***
  2227 
  2228 * greatly simplified document preparation setup, including more
  2229 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2230 instructive isatool mkdir; users should basically be able to get
  2231 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2232 users may run a separate document processing stage manually like this:
  2233 "isatool usedir -D output HOL Test && isatool document Test/output";
  2234 
  2235 * theory dependency graph may now be incorporated into documents;
  2236 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2237 with \includegraphics of LaTeX;
  2238 
  2239 * proper spacing of consecutive markup elements, especially text
  2240 blocks after section headings;
  2241 
  2242 * support bold style (for single symbols only), input syntax is like
  2243 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2244 
  2245 * \<bullet> is now output as bold \cdot by default, which looks much
  2246 better in printed text;
  2247 
  2248 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2249 note that these symbols are currently unavailable in Proof General /
  2250 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2251 
  2252 * isatool latex no longer depends on changed TEXINPUTS, instead
  2253 isatool document copies the Isabelle style files to the target
  2254 location;
  2255 
  2256 
  2257 *** Isar ***
  2258 
  2259 * Pure/Provers: improved proof by cases and induction;
  2260   - 'case' command admits impromptu naming of parameters (such as
  2261     "case (Suc n)");
  2262   - 'induct' method divinates rule instantiation from the inductive
  2263     claim; no longer requires excessive ?P bindings for proper
  2264     instantiation of cases;
  2265   - 'induct' method properly enumerates all possibilities of set/type
  2266     rules; as a consequence facts may be also passed through *type*
  2267     rules without further ado;
  2268   - 'induct' method now derives symbolic cases from the *rulified*
  2269     rule (before it used to rulify cases stemming from the internal
  2270     atomized version); this means that the context of a non-atomic
  2271     statement becomes is included in the hypothesis, avoiding the
  2272     slightly cumbersome show "PROP ?case" form;
  2273   - 'induct' may now use elim-style induction rules without chaining
  2274     facts, using ``missing'' premises from the goal state; this allows
  2275     rules stemming from inductive sets to be applied in unstructured
  2276     scripts, while still benefitting from proper handling of non-atomic
  2277     statements; NB: major inductive premises need to be put first, all
  2278     the rest of the goal is passed through the induction;
  2279   - 'induct' proper support for mutual induction involving non-atomic
  2280     rule statements (uses the new concept of simultaneous goals, see
  2281     below);
  2282   - append all possible rule selections, but only use the first
  2283     success (no backtracking);
  2284   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2285   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2286   - added 'print_induct_rules' (covered by help item in recent Proof
  2287     General versions);
  2288   - moved induct/cases attributes to Pure, methods to Provers;
  2289   - generic method setup instantiated for FOL and HOL;
  2290 
  2291 * Pure: support multiple simultaneous goal statements, for example
  2292 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2293 meta-level mechanism, this acts as if several individual goals had
  2294 been stated separately; in particular common proof methods need to be
  2295 repeated in order to cover all claims; note that a single elimination
  2296 step is *not* sufficient to establish the two conjunctions, so this
  2297 fails:
  2298 
  2299   assume "A & B" then have A and B ..   (*".." fails*)
  2300 
  2301 better use "obtain" in situations as above; alternative refer to
  2302 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2303 
  2304 * Pure: proper integration with ``locales''; unlike the original
  2305 version by Florian Kammller, Isar locales package high-level proof
  2306 contexts rather than raw logical ones (e.g. we admit to include
  2307 attributes everywhere); operations on locales include merge and
  2308 rename; support for implicit arguments (``structures''); simultaneous
  2309 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2310 some examples;
  2311 
  2312 * Pure: the following commands have been ``localized'', supporting a
  2313 target locale specification "(in name)": 'lemma', 'theorem',
  2314 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2315 stored both within the locale and at the theory level (exported and
  2316 qualified by the locale name);
  2317 
  2318 * Pure: theory goals may now be specified in ``long'' form, with
  2319 ad-hoc contexts consisting of arbitrary locale elements. for example
  2320 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2321 definitions may be given, too); the result is a meta-level rule with
  2322 the context elements being discharged in the obvious way;
  2323 
  2324 * Pure: new proof command 'using' allows to augment currently used
  2325 facts after a goal statement ('using' is syntactically analogous to
  2326 'apply', but acts on the goal's facts only); this allows chained facts
  2327 to be separated into parts given before and after a claim, as in
  2328 ``from a and b have C using d and e <proof>'';
  2329 
  2330 * Pure: renamed "antecedent" case to "rule_context";
  2331 
  2332 * Pure: new 'judgment' command records explicit information about the
  2333 object-logic embedding (used by several tools internally); no longer
  2334 use hard-wired "Trueprop";
  2335 
  2336 * Pure: added 'corollary' command;
  2337 
  2338 * Pure: fixed 'token_translation' command;
  2339 
  2340 * Pure: removed obsolete 'exported' attribute;
  2341 
  2342 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2343 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2344 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2345 
  2346 * Pure: method 'atomize' presents local goal premises as object-level
  2347 statements (atomic meta-level propositions); setup controlled via
  2348 rewrite rules declarations of 'atomize' attribute; example
  2349 application: 'induct' method with proper rule statements in improper
  2350 proof *scripts*;
  2351 
  2352 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2353 now consider the syntactic context of assumptions, giving a better
  2354 chance to get type-inference of the arguments right (this is
  2355 especially important for locales);
  2356 
  2357 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2358 mode;
  2359 
  2360 * Pure/obtain: the formal conclusion "thesis", being marked as
  2361 ``internal'', may no longer be reference directly in the text;
  2362 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2363 situations;
  2364 
  2365 * Pure: generic 'sym' attribute which declares a rule both as pure
  2366 'elim?' and for the 'symmetric' operation;
  2367 
  2368 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2369 text; the fixed correlation with particular command syntax has been
  2370 discontinued;
  2371 
  2372 * Pure: new method 'rules' is particularly well-suited for proof
  2373 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2374 but often produces more compact proof terms with less detours;
  2375 
  2376 * Pure/Provers/classical: simplified integration with pure rule
  2377 attributes and methods; the classical "intro?/elim?/dest?"
  2378 declarations coincide with the pure ones; the "rule" method no longer
  2379 includes classically swapped intros; "intro" and "elim" methods no
  2380 longer pick rules from the context; also got rid of ML declarations
  2381 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2382 INCOMPATIBILITY;
  2383 
  2384 * Provers/classical: attribute 'swapped' produces classical inversions
  2385 of introduction rules;
  2386 
  2387 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2388 rules instead of full simplifier context; 'iff' attribute handles
  2389 conditional rules;
  2390 
  2391 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2392 
  2393 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2394 "(permissive)" option to recover old behavior;
  2395 
  2396 * HOL: 'inductive' no longer features separate (collective) attributes
  2397 for 'intros' (was found too confusing);
  2398 
  2399 * HOL: properly declared induction rules less_induct and
  2400 wf_induct_rule;
  2401 
  2402 
  2403 *** HOL ***
  2404 
  2405 * HOL: moved over to sane numeral syntax; the new policy is as
  2406 follows:
  2407 
  2408   - 0 and 1 are polymorphic constants, which are defined on any
  2409   numeric type (nat, int, real etc.);
  2410 
  2411   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2412   binary representation internally;
  2413 
  2414   - type nat has special constructor Suc, and generally prefers Suc 0
  2415   over 1::nat and Suc (Suc 0) over 2::nat;
  2416 
  2417 This change may cause significant problems of INCOMPATIBILITY; here
  2418 are some hints on converting existing sources:
  2419 
  2420   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2421   entities, so expressions involving "-" (unary or binary minus) need
  2422   to be spaced properly;
  2423 
  2424   - existing occurrences of "1" may need to be constraint "1::nat" or
  2425   even replaced by Suc 0; similar for old "2";
  2426 
  2427   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2428 
  2429   - remove all special provisions on numerals in proofs;
  2430 
  2431 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2432 representation (depends on bin_arith_simps in the default context);
  2433 
  2434 * HOL: symbolic syntax for x^2 (numeral 2);
  2435 
  2436 * HOL: the class of all HOL types is now called "type" rather than
  2437 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2438 in axclass/classes, instance/arities, and (usually rare) occurrences
  2439 in typings (of consts etc.); internally the class is called
  2440 "HOL.type", ML programs should refer to HOLogic.typeS;
  2441 
  2442 * HOL/record package improvements:
  2443   - new derived operations "fields" to build a partial record section,
  2444     "extend" to promote a fixed record to a record scheme, and
  2445     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2446     declared as simp by default;
  2447   - shared operations ("more", "fields", etc.) now need to be always
  2448     qualified) --- potential INCOMPATIBILITY;
  2449   - removed "make_scheme" operations (use "make" with "extend") --
  2450     INCOMPATIBILITY;
  2451   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2452   - provides cases/induct rules for use with corresponding Isar
  2453     methods (for concrete records, record schemes, concrete more
  2454     parts, and schematic more parts -- in that order);
  2455   - internal definitions directly based on a light-weight abstract
  2456     theory of product types over typedef rather than datatype;
  2457 
  2458 * HOL: generic code generator for generating executable ML code from
  2459 specifications; specific support for HOL constructs such as inductive
  2460 datatypes and sets, as well as recursive functions; can be invoked
  2461 via 'generate_code' theory section;
  2462 
  2463 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2464 
  2465 * HOL: consolidated and renamed several theories.  In particular:
  2466         Ord.thy has been absorbed into HOL.thy
  2467         String.thy has been absorbed into List.thy
  2468 
  2469 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2470 (beware of argument permutation!);
  2471 
  2472 * HOL: linorder_less_split superseded by linorder_cases;
  2473 
  2474 * HOL/List: "nodups" renamed to "distinct";
  2475 
  2476 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2477 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2478   - Ex_def has changed, now need to use some_eq_ex
  2479 
  2480 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2481 in this (rare) case use:
  2482 
  2483   delSWrapper "split_all_tac"
  2484   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2485 
  2486 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2487 MAY FAIL;
  2488 
  2489 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2490 Isabelle's type classes, ^ on functions and relations has too general
  2491 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2492 necessary to attach explicit type constraints;
  2493 
  2494 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2495 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2496 renamed accordingly (eg "compI" -> "rel_compI").
  2497 
  2498 * HOL: syntax translations now work properly with numerals and records
  2499 expressions;
  2500 
  2501 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2502 of "lam" -- INCOMPATIBILITY;
  2503 
  2504 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2505 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2506 renamed "Product_Type.unit";
  2507 
  2508 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2509 
  2510 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2511 the "cases" method);
  2512 
  2513 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2514 Florian Kammller);
  2515 
  2516 * HOL/IMP: updated and converted to new-style theory format; several
  2517 parts turned into readable document, with proper Isar proof texts and
  2518 some explanations (by Gerwin Klein);
  2519 
  2520 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2521 
  2522 * HOL-Hyperreal is now a logic image;
  2523 
  2524 
  2525 *** HOLCF ***
  2526 
  2527 * Isar: consts/constdefs supports mixfix syntax for continuous
  2528 operations;
  2529 
  2530 * Isar: domain package adapted to new-style theory format, e.g. see
  2531 HOLCF/ex/Dnat.thy;
  2532 
  2533 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2534 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2535 lift.induct_tac, always use UU instead of Undef;
  2536 
  2537 * HOLCF/IMP: updated and converted to new-style theory;
  2538 
  2539 
  2540 *** ZF ***
  2541 
  2542 * Isar: proper integration of logic-specific tools and packages,
  2543 including theory commands '(co)inductive', '(co)datatype',
  2544 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2545 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2546 
  2547 * theory Main no longer includes AC; for the Axiom of Choice, base
  2548 your theory on Main_ZFC;
  2549 
  2550 * the integer library now covers quotients and remainders, with many
  2551 laws relating division to addition, multiplication, etc.;
  2552 
  2553 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2554 typeless version of the formalism;
  2555 
  2556 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2557 format;
  2558 
  2559 * ZF/Induct: new directory for examples of inductive definitions,
  2560 including theory Multiset for multiset orderings; converted to
  2561 new-style theory format;
  2562 
  2563 * ZF: many new theorems about lists, ordinals, etc.;
  2564 
  2565 
  2566 *** General ***
  2567 
  2568 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2569 variable proof controls level of detail: 0 = no proofs (only oracle
  2570 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2571 also ref manual for further ML interfaces;
  2572 
  2573 * Pure/axclass: removed obsolete ML interface
  2574 goal_subclass/goal_arity;
  2575 
  2576 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2577 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2578 separate tokens, so expressions involving minus need to be spaced
  2579 properly;
  2580 
  2581 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2582 rather than "infixl" or "infixr";
  2583 
  2584 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2585 sort constraint specifications in type inference; e.g. "x::_::foo"
  2586 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2587 type variable);
  2588 
  2589 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2590 control output of nested => (types); the default behavior is
  2591 "type_brackets";
  2592 
  2593 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2594 tokens into AST constants;
  2595 
  2596 * Pure/syntax: prefer later declarations of translations and print
  2597 translation functions; potential INCOMPATIBILITY: need to reverse
  2598 multiple declarations for same syntax element constant;
  2599 
  2600 * Pure/show_hyps reset by default (in accordance to existing Isar
  2601 practice);
  2602 
  2603 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2604 addSafter;
  2605 
  2606 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2607 as well;
  2608 
  2609 * system: tested support for MacOS X; should be able to get Isabelle +
  2610 Proof General to work in a plain Terminal after installing Poly/ML
  2611 (e.g. from the Isabelle distribution area) and GNU bash alone
  2612 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2613 support requires further installations, e.g. from
  2614 http://fink.sourceforge.net/);
  2615 
  2616 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2617 
  2618 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2619 of 40 MB), cf. ML_OPTIONS;
  2620 
  2621 * system: Proof General keywords specification is now part of the
  2622 Isabelle distribution (see etc/isar-keywords.el);
  2623 
  2624 * system: support for persistent Proof General sessions (refrain from
  2625 outdating all loaded theories on startup); user may create writable
  2626 logic images like this: ``isabelle -q HOL Test'';
  2627 
  2628 * system: smart selection of Isabelle process versus Isabelle
  2629 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2630 run both "isabelle" and "Isabelle" even if file names are badly
  2631 damaged (executable inspects the case of the first letter of its own
  2632 name); added separate "isabelle-process" and "isabelle-interface";
  2633 
  2634 * system: refrain from any attempt at filtering input streams; no
  2635 longer support ``8bit'' encoding of old isabelle font, instead proper
  2636 iso-latin characters may now be used; the related isatools
  2637 "symbolinput" and "nonascii" have disappeared as well;
  2638 
  2639 * system: removed old "xterm" interface (the print modes "xterm" and
  2640 "xterm_color" are still available for direct use in a suitable
  2641 terminal);
  2642 
  2643 
  2644 
  2645 New in Isabelle99-2 (February 2001)
  2646 -----------------------------------
  2647 
  2648 *** Overview of INCOMPATIBILITIES ***
  2649 
  2650 * HOL: please note that theories in the Library and elsewhere often use the
  2651 new-style (Isar) format; to refer to their theorems in an ML script you must
  2652 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2653 
  2654 * HOL: inductive package no longer splits induction rule aggressively,
  2655 but only as far as specified by the introductions given; the old
  2656 format may be recovered via ML function complete_split_rule or attribute
  2657 'split_rule (complete)';
  2658 
  2659 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2660 gfp_Tarski to gfp_unfold;
  2661 
  2662 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2663 
  2664 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2665 relation); infix "^^" has been renamed "``"; infix "``" has been
  2666 renamed "`"; "univalent" has been renamed "single_valued";
  2667 
  2668 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2669 operation;
  2670 
  2671 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2672 
  2673 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2674 
  2675 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2676 consequence, it is no longer monotonic wrt. the local goal context
  2677 (which is now passed through the inductive cases);
  2678 
  2679 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2680 \<gg> to \<ggreater>;
  2681 
  2682 
  2683 *** Document preparation ***
  2684 
  2685 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2686 available: are "it" for near math-mode best-style output, "sl" for
  2687 slanted text style, and "tt" for plain type-writer; if no
  2688 \isabellestyle command is given, output is according to slanted
  2689 type-writer);
  2690 
  2691 * support sub/super scripts (for single symbols only), input syntax is
  2692 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2693 
  2694 * some more standard symbols; see Appendix A of the system manual for
  2695 the complete list of symbols defined in isabellesym.sty;
  2696 
  2697 * improved isabelle style files; more abstract symbol implementation
  2698 (should now use \isamath{...} and \isatext{...} in custom symbol
  2699 definitions);
  2700 
  2701 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2702 state; Note that presentation of goal states does not conform to
  2703 actual human-readable proof documents.  Please do not include goal
  2704 states into document output unless you really know what you are doing!
  2705 
  2706 * proper indentation of antiquoted output with proportional LaTeX
  2707 fonts;
  2708 
  2709 * no_document ML operator temporarily disables LaTeX document
  2710 generation;
  2711 
  2712 * isatool unsymbolize tunes sources for plain ASCII communication;
  2713 
  2714 
  2715 *** Isar ***
  2716 
  2717 * Pure: Isar now suffers initial goal statements to contain unbound
  2718 schematic variables (this does not conform to actual readable proof
  2719 documents, due to unpredictable outcome and non-compositional proof
  2720 checking); users who know what they are doing may use schematic goals
  2721 for Prolog-style synthesis of proven results;
  2722 
  2723 * Pure: assumption method (an implicit finishing) now handles actual
  2724 rules as well;
  2725 
  2726 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  2727 initial goal, declare "that" only as Pure intro (only for single
  2728 steps); the "that" rule assumption may now be involved in implicit
  2729 finishing, thus ".." becomes a feasible for trivial obtains;
  2730 
  2731 * Pure: default proof step now includes 'intro_classes'; thus trivial
  2732 instance proofs may be performed by "..";
  2733 
  2734 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  2735 statements as well;
  2736 
  2737 * Pure: more robust selection of calculational rules;
  2738 
  2739 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  2740 rule (as well as the assumption rule);
  2741 
  2742 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  2743 lemmas, using the graph browser tool;
  2744 
  2745 * Pure: predict failure of "show" in interactive mode;
  2746 
  2747 * Pure: 'thms_containing' now takes actual terms as arguments;
  2748 
  2749 * HOL: improved method 'induct' --- now handles non-atomic goals
  2750 (potential INCOMPATIBILITY); tuned error handling;
  2751 
  2752 * HOL: cases and induct rules now provide explicit hints about the
  2753 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  2754 any remaining facts are inserted into the goal verbatim;
  2755 
  2756 * HOL: local contexts (aka cases) may now contain term bindings as
  2757 well; the 'cases' and 'induct' methods new provide a ?case binding for
  2758 the result to be shown in each case;
  2759 
  2760 * HOL: added 'recdef_tc' command;
  2761 
  2762 * isatool convert assists in eliminating legacy ML scripts;
  2763 
  2764 
  2765 *** HOL ***
  2766 
  2767 * HOL/Library: a collection of generic theories to be used together
  2768 with main HOL; the theory loader path already includes this directory
  2769 by default; the following existing theories have been moved here:
  2770 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  2771 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  2772 
  2773 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  2774 modelling and verification task performed in Isabelle/HOL +
  2775 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  2776 
  2777 * HOL/Algebra: special summation operator SUM no longer exists, it has
  2778 been replaced by setsum; infix 'assoc' now has priority 50 (like
  2779 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  2780 'domain', this makes the theory consistent with mathematical
  2781 literature;
  2782 
  2783 * HOL basics: added overloaded operations "inverse" and "divide"
  2784 (infix "/"), syntax for generic "abs" operation, generic summation
  2785 operator \<Sum>;
  2786 
  2787 * HOL/typedef: simplified package, provide more useful rules (see also
  2788 HOL/subset.thy);
  2789 
  2790 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  2791 now expressed as a proper nested rule (old-style tactic scripts may
  2792 require atomize_strip_tac to cope with non-atomic premises);
  2793 
  2794 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  2795 to "split_conv" (old name still available for compatibility);
  2796 
  2797 * HOL: improved concrete syntax for strings (e.g. allows translation
  2798 rules with string literals);
  2799 
  2800 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  2801  and Fleuriot's mechanization of analysis, including the transcendental
  2802  functions for the reals;
  2803 
  2804 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  2805 
  2806 
  2807 *** CTT ***
  2808 
  2809 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2810 "lam" is displayed as TWO lambda-symbols
  2811 
  2812 * CTT: theory Main now available, containing everything (that is, Bool
  2813 and Arith);
  2814 
  2815 
  2816 *** General ***
  2817 
  2818 * Pure: the Simplifier has been implemented properly as a derived rule
  2819 outside of the actual kernel (at last!); the overall performance
  2820 penalty in practical applications is about 50%, while reliability of
  2821 the Isabelle inference kernel has been greatly improved;
  2822 
  2823 * print modes "brackets" and "no_brackets" control output of nested =>
  2824 (types) and ==> (props); the default behaviour is "brackets";
  2825 
  2826 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2827 as assumptions as well;
  2828 
  2829 * system: support Poly/ML 4.0;
  2830 
  2831 * system: isatool install handles KDE version 1 or 2;
  2832 
  2833 
  2834 
  2835 New in Isabelle99-1 (October 2000)
  2836 ----------------------------------
  2837 
  2838 *** Overview of INCOMPATIBILITIES ***
  2839 
  2840 * HOL: simplification of natural numbers is much changed; to partly
  2841 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  2842 issue the following ML commands:
  2843 
  2844   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  2845   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  2846 
  2847 * HOL: simplification no longer dives into case-expressions; this is
  2848 controlled by "t.weak_case_cong" for each datatype t;
  2849 
  2850 * HOL: nat_less_induct renamed to less_induct;
  2851 
  2852 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  2853 fixsome to patch .thy and .ML sources automatically;
  2854 
  2855   select_equality  -> some_equality
  2856   select_eq_Ex     -> some_eq_ex
  2857   selectI2EX       -> someI2_ex
  2858   selectI2         -> someI2
  2859   selectI          -> someI
  2860   select1_equality -> some1_equality
  2861   Eps_sym_eq       -> some_sym_eq_trivial
  2862   Eps_eq           -> some_eq_trivial
  2863 
  2864 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  2865 
  2866 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  2867 instead);
  2868 
  2869 * HOL: the recursion equations generated by 'recdef' are now called
  2870 f.simps instead of f.rules;
  2871 
  2872 * HOL: qed_spec_mp now also handles bounded ALL as well;
  2873 
  2874 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  2875 sometimes be needed;
  2876 
  2877 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  2878 
  2879 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  2880 
  2881 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  2882 product is now "<*>" instead of "Times"; the lexicographic product is
  2883 now "<*lex*>" instead of "**";
  2884 
  2885 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  2886 of main HOL, but was unused); better use HOL's datatype package;
  2887 
  2888 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  2889 the old syntax may be recovered as follows:
  2890 
  2891   syntax (symbols)
  2892     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  2893       (infixl "\\<oplus>" 100)
  2894 
  2895 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2896 
  2897 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  2898 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  2899 internally;
  2900 
  2901 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  2902 changed from A/r to A//r;
  2903 
  2904 * ZF: new treatment of arithmetic (nat & int) may break some old
  2905 proofs;
  2906 
  2907 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  2908 rulify -> rule_format, elimify -> elim_format, ...);
  2909 
  2910 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2911 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  2912 should have to change intro!! to intro? only); replaced "delrule" by
  2913 "rule del";
  2914 
  2915 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  2916 
  2917 * Provers: strengthened force_tac by using new first_best_tac;
  2918 
  2919 * LaTeX document preparation: several changes of isabelle.sty (see
  2920 lib/texinputs);
  2921 
  2922 
  2923 *** Document preparation ***
  2924 
  2925 * formal comments (text blocks etc.) in new-style theories may now
  2926 contain antiquotations of thm/prop/term/typ/text to be presented
  2927 according to latex print mode; concrete syntax is like this:
  2928 @{term[show_types] "f(x) = a + x"};
  2929 
  2930 * isatool mkdir provides easy setup of Isabelle session directories,
  2931 including proper document sources;
  2932 
  2933 * generated LaTeX sources are now deleted after successful run
  2934 (isatool document -c); may retain a copy somewhere else via -D option
  2935 of isatool usedir;
  2936 
  2937 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  2938 style files, achieving self-contained LaTeX sources and simplifying
  2939 LaTeX debugging;
  2940 
  2941 * old-style theories now produce (crude) LaTeX output as well;
  2942 
  2943 * browser info session directories are now self-contained (may be put
  2944 on WWW server seperately); improved graphs of nested sessions; removed
  2945 graph for 'all sessions';
  2946 
  2947 * several improvements in isabelle style files; \isabellestyle{it}
  2948 produces fake math mode output; \isamarkupheader is now \section by
  2949 default; see lib/texinputs/isabelle.sty etc.;
  2950 
  2951 
  2952 *** Isar ***
  2953 
  2954 * Isar/Pure: local results and corresponding term bindings are now
  2955 subject to Hindley-Milner polymorphism (similar to ML); this
  2956 accommodates incremental type-inference very nicely;
  2957 
  2958 * Isar/Pure: new derived language element 'obtain' supports
  2959 generalized existence reasoning;
  2960 
  2961 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  2962 support accumulation of results, without applying any rules yet;
  2963 useful to collect intermediate results without explicit name
  2964 references, and for use with transitivity rules with more than 2
  2965 premises;
  2966 
  2967 * Isar/Pure: scalable support for case-analysis type proofs: new
  2968 'case' language element refers to local contexts symbolically, as
  2969 produced by certain proof methods; internally, case names are attached
  2970 to theorems as "tags";
  2971 
  2972 * Isar/Pure: theory command 'hide' removes declarations from
  2973 class/type/const name spaces;
  2974 
  2975 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  2976 indicate potential overloading;
  2977 
  2978 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  2979 
  2980 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  2981 "{a,b,c}" instead of {a,b,c};
  2982 
  2983 * Isar/Pure now provides its own version of intro/elim/dest
  2984 attributes; useful for building new logics, but beware of confusion
  2985 with the version in Provers/classical;
  2986 
  2987 * Isar/Pure: the local context of (non-atomic) goals is provided via
  2988 case name 'antecedent';
  2989 
  2990 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  2991 to the current context is now done automatically);
  2992 
  2993 * Isar/Pure: theory command 'method_setup' provides a simple interface
  2994 for definining proof methods in ML;
  2995 
  2996 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2997 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  2998 most cases, one should have to change intro!! to intro? only);
  2999 replaced "delrule" by "rule del";
  3000 
  3001 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3002 'symmetric' attribute (the latter supercedes [RS sym]);
  3003 
  3004 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3005 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3006 well (including splits);
  3007 
  3008 * Isar/Provers: Simplifier and Classical methods now support all kind
  3009 of modifiers used in the past, including 'cong', 'iff', etc.
  3010 
  3011 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3012 of Simplifier and Classical reasoner);
  3013 
  3014 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3015 now support named cases; major packages (inductive, datatype, primrec,
  3016 recdef) support case names and properly name parameters;
  3017 
  3018 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3019 monotonicity conditions are extracted to be proven at end of
  3020 calculations;
  3021 
  3022 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3023 method anyway;
  3024 
  3025 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3026 split_if split_if_asm; datatype package provides theorems foo.splits =
  3027 foo.split foo.split_asm for each datatype;
  3028 
  3029 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3030 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3031 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3032 use "(cases (simplified))" method in proper proof texts);
  3033 
  3034 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3035 
  3036 * Isar: names of theorems etc. may be natural numbers as well;
  3037 
  3038 * Isar: 'pr' command: optional arguments for goals_limit and
  3039 ProofContext.prems_limit; no longer prints theory contexts, but only
  3040 proof states;
  3041 
  3042 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3043 additional print modes to be specified; e.g. "pr(latex)" will print
  3044 proof state according to the Isabelle LaTeX style;
  3045 
  3046 * Isar: improved support for emulating tactic scripts, including proof
  3047 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3048 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3049 (for HOL datatypes);
  3050 
  3051 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3052 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3053 'proof method scripts' have to be in depth-first order;
  3054 
  3055 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3056 
  3057 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3058 should instead use individual commands for printing items
  3059 (print_commands, print_methods etc.);
  3060 
  3061 * Isar: added 'nothing' --- the empty list of theorems;
  3062 
  3063 
  3064 *** HOL ***
  3065 
  3066 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3067 corresponding virtual machine and a specification of its bytecode
  3068 verifier and a lightweight bytecode verifier, including proofs of
  3069 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3070 Cornelia Pusch (see also the homepage of project Bali at
  3071 http://isabelle.in.tum.de/Bali/);
  3072 
  3073 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3074 Clemens Ballarin;
  3075 
  3076 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3077 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3078 Rasmussen;
  3079 
  3080 * HOL/Lattice: fundamental concepts of lattice theory and order
  3081 structures, including duals, properties of bounds versus algebraic
  3082 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3083 Theorem for complete lattices etc.; may also serve as a demonstration
  3084 for abstract algebraic reasoning using axiomatic type classes, and
  3085 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3086 
  3087 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3088 von Oheimb;
  3089 
  3090 * HOL/IMPP: extension of IMP with local variables and mutually
  3091 recursive procedures, by David von Oheimb;
  3092 
  3093 * HOL/Lambda: converted into new-style theory and document;
  3094 
  3095 * HOL/ex/Multiquote: example of multiple nested quotations and
  3096 anti-quotations -- basically a generalized version of de-Bruijn
  3097 representation; very useful in avoiding lifting of operations;
  3098 
  3099 * HOL/record: added general record equality rule to simpset; fixed
  3100 select-update simplification procedure to handle extended records as
  3101 well; admit "r" as field name;
  3102 
  3103 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3104 other numeric types and also as the identity of groups, rings, etc.;
  3105 
  3106 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3107 Types nat and int belong to this axclass;
  3108 
  3109 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3110    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3111    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3112   two terms #m*u and #n*u are replaced by #(m+n)*u
  3113     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3114   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3115     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3116 
  3117 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3118 powerful prover for predicate logic but knows nothing of clasets; see
  3119 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3120 
  3121 * HOL: new version of "case_tac" subsumes both boolean case split and
  3122 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3123 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3124 
  3125 * HOL: simplification no longer dives into case-expressions: only the
  3126 selector expression is simplified, but not the remaining arms; to
  3127 enable full simplification of case-expressions for datatype t, you may
  3128 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3129 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3130 
  3131 * HOL/recdef: the recursion equations generated by 'recdef' for
  3132 function 'f' are now called f.simps instead of f.rules; if all
  3133 termination conditions are proved automatically, these simplification
  3134 rules are added to the simpset, as in primrec; rules may be named
  3135 individually as well, resulting in a separate list of theorems for
  3136 each equation;
  3137 
  3138 * HOL/While is a new theory that provides a while-combinator. It
  3139 permits the definition of tail-recursive functions without the
  3140 provision of a termination measure. The latter is necessary once the
  3141 invariant proof rule for while is applied.
  3142 
  3143 * HOL: new (overloaded) notation for the set of elements below/above
  3144 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3145 
  3146 * HOL: theorems impI, allI, ballI bound as "strip";
  3147 
  3148 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3149 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3150 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3151 
  3152 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3153 
  3154 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3155 main HOL, but was unused);
  3156 
  3157 * HOL: fewer consts declared as global (e.g. have to refer to
  3158 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3159 
  3160 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3161 in case of overlap with user translations (e.g. judgements over
  3162 tuples); (note that the underlying logical represenation is still
  3163 bogus);
  3164 
  3165 
  3166 *** ZF ***
  3167 
  3168 * ZF: simplification automatically cancels common terms in arithmetic
  3169 expressions over nat and int;
  3170 
  3171 * ZF: new treatment of nat to minimize type-checking: all operators
  3172 coerce their operands to a natural number using the function natify,
  3173 making the algebraic laws unconditional;
  3174 
  3175 * ZF: as above, for int: operators coerce their operands to an integer
  3176 using the function intify;
  3177 
  3178 * ZF: the integer library now contains many of the usual laws for the
  3179 orderings, including $<=, and monotonicity laws for $+ and $*;
  3180 
  3181 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3182 simplification;
  3183 
  3184 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3185 to the simplifier and classical reasoner simultaneously;
  3186 
  3187 
  3188 *** General ***
  3189 
  3190 * Provers: blast_tac now handles actual object-logic rules as
  3191 assumptions; note that auto_tac uses blast_tac internally as well;
  3192 
  3193 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3194 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3195 
  3196 * Provers: delrules now handles destruct rules as well (no longer need
  3197 explicit make_elim);
  3198 
  3199 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3200   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3201 use instead the strong form,
  3202   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3203 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3204 from destruct-rules;
  3205 
  3206 * Provers: Simplifier.easy_setup provides a fast path to basic
  3207 Simplifier setup for new object-logics;
  3208 
  3209 * Pure: AST translation rules no longer require constant head on LHS;
  3210 
  3211 * Pure: improved name spaces: ambiguous output is qualified; support
  3212 for hiding of names;
  3213 
  3214 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3215 XSYMBOL_HOME; no longer need to do manual configuration in most
  3216 situations;
  3217 
  3218 * system: compression of ML heaps images may now be controlled via -c
  3219 option of isabelle and isatool usedir (currently only observed by
  3220 Poly/ML);
  3221 
  3222 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3223 useful for remote X11);
  3224 
  3225 * system: provide TAGS file for Isabelle sources;
  3226 
  3227 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3228 order;
  3229 
  3230 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3231 timing flag supersedes proof_timing and Toplevel.trace;
  3232 
  3233 * ML: new combinators |>> and |>>> for incremental transformations
  3234 with secondary results (e.g. certain theory extensions):
  3235 
  3236 * ML: PureThy.add_defs gets additional argument to indicate potential
  3237 overloading (usually false);
  3238 
  3239 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3240 results;
  3241 
  3242 
  3243 
  3244 New in Isabelle99 (October 1999)
  3245 --------------------------------
  3246 
  3247 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3248 
  3249 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3250 are no longer simplified.  (This allows the simplifier to unfold recursive
  3251 functional programs.)  To restore the old behaviour, declare
  3252 
  3253     Delcongs [if_weak_cong];
  3254 
  3255 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3256 complement;
  3257 
  3258 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3259 
  3260 * HOL/datatype: mutual_induct_tac no longer exists --
  3261   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3262 
  3263 * HOL/typedef: fixed type inference for representing set; type
  3264 arguments now have to occur explicitly on the rhs as type constraints;
  3265 
  3266 * ZF: The con_defs part of an inductive definition may no longer refer
  3267 to constants declared in the same theory;
  3268 
  3269 * HOL, ZF: the function mk_cases, generated by the inductive
  3270 definition package, has lost an argument.  To simplify its result, it
  3271 uses the default simpset instead of a supplied list of theorems.
  3272 
  3273 * HOL/List: the constructors of type list are now Nil and Cons;
  3274 
  3275 * Simplifier: the type of the infix ML functions
  3276         setSSolver addSSolver setSolver addSolver
  3277 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3278 for packaging solvers. A solver is created via
  3279         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3280 where the string argument is only a comment.
  3281 
  3282 
  3283 *** Proof tools ***
  3284 
  3285 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3286 decision procedure for linear arithmetic. Currently it is used for
  3287 types `nat', `int', and `real' in HOL (see below); it can, should and
  3288 will be instantiated for other types and logics as well.
  3289 
  3290 * The simplifier now accepts rewrite rules with flexible heads, eg
  3291      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3292   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3293   matching.
  3294 
  3295 
  3296 *** General ***
  3297 
  3298 * New Isabelle/Isar subsystem provides an alternative to traditional
  3299 tactical theorem proving; together with the ProofGeneral/isar user
  3300 interface it offers an interactive environment for developing human
  3301 readable proof documents (Isar == Intelligible semi-automated
  3302 reasoning); for further information see isatool doc isar-ref,
  3303 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3304 
  3305 * improved and simplified presentation of theories: better HTML markup
  3306 (including colors), graph views in several sizes; isatool usedir now
  3307 provides a proper interface for user theories (via -P option); actual
  3308 document preparation based on (PDF)LaTeX is available as well (for
  3309 new-style theories only); see isatool doc system for more information;
  3310 
  3311 * native support for Proof General, both for classic Isabelle and
  3312 Isabelle/Isar;
  3313 
  3314 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3315 using the graph browser tool;
  3316 
  3317 * Isabelle manuals now also available as PDF;
  3318 
  3319 * theory loader rewritten from scratch (may not be fully
  3320 bug-compatible); old loadpath variable has been replaced by show_path,
  3321 add_path, del_path, reset_path functions; new operations such as
  3322 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3323 isatool doc ref);
  3324 
  3325 * improved isatool install: option -k creates KDE application icon,
  3326 option -p DIR installs standalone binaries;
  3327 
  3328 * added ML_PLATFORM setting (useful for cross-platform installations);
  3329 more robust handling of platform specific ML images for SML/NJ;
  3330 
  3331 * the settings environment is now statically scoped, i.e. it is never
  3332 created again in sub-processes invoked from isabelle, isatool, or
  3333 Isabelle;
  3334 
  3335 * path element specification '~~' refers to '$ISABELLE_HOME';
  3336 
  3337 * in locales, the "assumes" and "defines" parts may be omitted if
  3338 empty;
  3339 
  3340 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3341 long arrows);
  3342 
  3343 * new print_mode "HTML";
  3344 
  3345 * new flag show_tags controls display of tags of theorems (which are
  3346 basically just comments that may be attached by some tools);
  3347 
  3348 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3349 mode and goal output format:
  3350 
  3351 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3352 244c244
  3353 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3354 ---
  3355 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3356 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3357 181c181
  3358 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3359 ---
  3360 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3361 
  3362 * function bind_thms stores lists of theorems (cf. bind_thm);
  3363 
  3364 * new shorthand tactics ftac, eatac, datac, fatac;
  3365 
  3366 * qed (and friends) now accept "" as result name; in that case the
  3367 theorem is not stored, but proper checks and presentation of the
  3368 result still apply;
  3369 
  3370 * theorem database now also indexes constants "Trueprop", "all",
  3371 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3372 
  3373 
  3374 *** HOL ***
  3375 
  3376 ** HOL arithmetic **
  3377 
  3378 * There are now decision procedures for linear arithmetic over nat and
  3379 int:
  3380 
  3381 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3382 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3383 are treated as atomic; subformulae not involving type `nat' or `int'
  3384 are ignored; quantified subformulae are ignored unless they are
  3385 positive universal or negative existential. The tactic has to be
  3386 invoked by hand and can be a little bit slow. In particular, the
  3387 running time is exponential in the number of occurrences of `min' and
  3388 `max', and `-' on `nat'.
  3389 
  3390 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3391 (negated) (in)equalities among the premises and the conclusion into
  3392 account (i.e. no compound formulae) and does not know about `min' and
  3393 `max', and `-' on `nat'. It is fast and is used automatically by the
  3394 simplifier.
  3395 
  3396 NB: At the moment, these decision procedures do not cope with mixed
  3397 nat/int formulae where the two parts interact, such as `m < n ==>
  3398 int(m) < int(n)'.
  3399 
  3400 * HOL/Numeral provides a generic theory of numerals (encoded
  3401 efficiently as bit strings); setup for types nat/int/real is in place;
  3402 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3403 int, existing theories and proof scripts may require a few additional
  3404 type constraints;
  3405 
  3406 * integer division and remainder can now be performed on constant
  3407 arguments;
  3408 
  3409 * many properties of integer multiplication, division and remainder
  3410 are now available;
  3411 
  3412 * An interface to the Stanford Validity Checker (SVC) is available through the
  3413 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3414 are proved automatically.  SVC must be installed separately, and its results
  3415 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3416 invocation of the underlying oracle).  For SVC see
  3417   http://verify.stanford.edu/SVC
  3418 
  3419 * IsaMakefile: the HOL-Real target now builds an actual image;
  3420 
  3421 
  3422 ** HOL misc **
  3423 
  3424 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3425 (in Isabelle/Isar) -- by Gertrud Bauer;
  3426 
  3427 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3428 analysis for assembly languages with subtypes;
  3429 
  3430 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3431 -- avoids syntactic ambiguities and treats state, transition, and
  3432 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3433 changed syntax and (many) tactics;
  3434 
  3435 * HOL/inductive: Now also handles more general introduction rules such
  3436   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3437   theorems are now maintained within the theory (maintained via the
  3438   "mono" attribute);
  3439 
  3440 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3441   (using function types) such as
  3442 
  3443   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3444 
  3445 * HOL/record: record_simproc (part of the default simpset) takes care
  3446 of selectors applied to updated records; record_split_tac is no longer
  3447 part of the default claset; update_defs may now be removed from the
  3448 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3449 
  3450   claset_ref () := claset() addSWrapper record_split_wrapper;
  3451   Delsimprocs [record_simproc]
  3452 
  3453 * HOL/typedef: fixed type inference for representing set; type
  3454 arguments now have to occur explicitly on the rhs as type constraints;
  3455 
  3456 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3457 names rather than an ML expression;
  3458 
  3459 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3460 supplied later.  Program schemes can be defined, such as
  3461     "While B C s = (if B s then While B C (C s) else s)"
  3462 where the well-founded relation can be chosen after B and C have been given.
  3463 
  3464 * HOL/List: the constructors of type list are now Nil and Cons;
  3465 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3466 course, ML tools referring to List.list.op # etc. have to be adapted;
  3467 
  3468 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3469 disabled by default; run isabelle with option -m HOL to get back to
  3470 the original Gordon/HOL-style output;
  3471 
  3472 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3473 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3474 
  3475 * HOL basic syntax simplified (more orthogonal): all variants of
  3476 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3477 Eps operator is provided as well: "SOME x. P[x]";
  3478 
  3479 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3480 
  3481 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3482 thus available for user theories;
  3483 
  3484 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3485 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3486 time;
  3487 
  3488 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3489 several times and then mp;
  3490 
  3491 
  3492 *** LK ***
  3493 
  3494 * the notation <<...>> is now available as a notation for sequences of
  3495 formulas;
  3496 
  3497 * the simplifier is now installed
  3498 
  3499 * the axiom system has been generalized (thanks to Soren Heilmann)
  3500 
  3501 * the classical reasoner now has a default rule database
  3502 
  3503 
  3504 *** ZF ***
  3505 
  3506 * new primrec section allows primitive recursive functions to be given
  3507 directly (as in HOL) over datatypes and the natural numbers;
  3508 
  3509 * new tactics induct_tac and exhaust_tac for induction (or case
  3510 analysis) over datatypes and the natural numbers;
  3511 
  3512 * the datatype declaration of type T now defines the recursor T_rec;
  3513 
  3514 * simplification automatically does freeness reasoning for datatype
  3515 constructors;
  3516 
  3517 * automatic type-inference, with AddTCs command to insert new
  3518 type-checking rules;
  3519 
  3520 * datatype introduction rules are now added as Safe Introduction rules
  3521 to the claset;
  3522 
  3523 * the syntax "if P then x else y" is now available in addition to
  3524 if(P,x,y);
  3525 
  3526 
  3527 *** Internal programming interfaces ***
  3528 
  3529 * tuned simplifier trace output; new flag debug_simp;
  3530 
  3531 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3532 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3533 
  3534 * AxClass.axclass_tac lost the theory argument;
  3535 
  3536 * tuned current_goals_markers semantics: begin / end goal avoids
  3537 printing empty lines;
  3538 
  3539 * removed prs and prs_fn hook, which was broken because it did not
  3540 include \n in its semantics, forcing writeln to add one
  3541 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3542 string -> unit if you really want to output text without newline;
  3543 
  3544 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3545 plain output, interface builders may have to enable 'isabelle_font'
  3546 mode to get Isabelle font glyphs as before;
  3547 
  3548 * refined token_translation interface; INCOMPATIBILITY: output length
  3549 now of type real instead of int;
  3550 
  3551 * theory loader actions may be traced via new ThyInfo.add_hook
  3552 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3553 your own database of information attached to *whole* theories -- as
  3554 opposed to intra-theory data slots offered via TheoryDataFun;
  3555 
  3556 * proper handling of dangling sort hypotheses (at last!);
  3557 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3558 extra sort hypotheses that can be witnessed from the type signature;
  3559 the force_strip_shyps flag is gone, any remaining shyps are simply
  3560 left in the theorem (with a warning issued by strip_shyps_warning);
  3561 
  3562 
  3563 
  3564 New in Isabelle98-1 (October 1998)
  3565 ----------------------------------
  3566 
  3567 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3568 
  3569 * several changes of automated proof tools;
  3570 
  3571 * HOL: major changes to the inductive and datatype packages, including
  3572 some minor incompatibilities of theory syntax;
  3573 
  3574 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3575 called `inj_on';
  3576 
  3577 * HOL: removed duplicate thms in Arith:
  3578   less_imp_add_less  should be replaced by  trans_less_add1
  3579   le_imp_add_le      should be replaced by  trans_le_add1
  3580 
  3581 * HOL: unary minus is now overloaded (new type constraints may be
  3582 required);
  3583 
  3584 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3585 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3586 now taken as an integer constant.
  3587 
  3588 * Pure: ML function 'theory_of' renamed to 'theory';
  3589 
  3590 
  3591 *** Proof tools ***
  3592 
  3593 * Simplifier:
  3594   1. Asm_full_simp_tac is now more aggressive.
  3595      1. It will sometimes reorient premises if that increases their power to
  3596         simplify.
  3597      2. It does no longer proceed strictly from left to right but may also
  3598         rotate premises to achieve further simplification.
  3599      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3600      old Asm_full_simp_tac in that it does not rotate premises.
  3601   2. The simplifier now knows a little bit about nat-arithmetic.
  3602 
  3603 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3604 allows for selected deletion of wrappers, by introduction of names for
  3605 wrapper functionals.  This implies that addbefore, addSbefore,
  3606 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3607 and that adding two tactics with the same name overwrites the first
  3608 one (emitting a warning).
  3609   type wrapper = (int -> tactic) -> (int -> tactic)
  3610   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3611   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3612   delWrapper, delSWrapper: claset *  string            -> claset
  3613   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3614 
  3615 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3616 semantics; addbefore now affects only the unsafe part of step_tac
  3617 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3618 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3619 by Force_tac;
  3620 
  3621 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3622 compWrapper; added safe wrapper (and access functions for it);
  3623 
  3624 * HOL/split_all_tac is now much faster and fails if there is nothing
  3625 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3626 and the names of the automatically generated variables have changed.
  3627 split_all_tac has moved within claset() from unsafe wrappers to safe
  3628 wrappers, which means that !!-bound variables are split much more
  3629 aggressively, and safe_tac and clarify_tac now split such variables.
  3630 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3631 Note: the same holds for record_split_tac, which does the job of
  3632 split_all_tac for record fields.
  3633 
  3634 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3635 permanently to the default simpset using Addsplits just like
  3636 Addsimps. They can be removed via Delsplits just like
  3637 Delsimps. Lower-case versions are also available.
  3638 
  3639 * HOL/Simplifier: The rule split_if is now part of the default
  3640 simpset. This means that the simplifier will eliminate all occurrences
  3641 of if-then-else in the conclusion of a goal. To prevent this, you can
  3642 either remove split_if completely from the default simpset by
  3643 `Delsplits [split_if]' or remove it in a specific call of the
  3644 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3645 other case splitting rules to/from the default simpset: every datatype
  3646 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3647 t is the name of the datatype).
  3648 
  3649 * Classical reasoner / Simplifier combination: new force_tac (and
  3650 derivatives Force_tac, force) combines rewriting and classical
  3651 reasoning (and whatever other tools) similarly to auto_tac, but is
  3652 aimed to solve the given subgoal completely.
  3653 
  3654 
  3655 *** General ***
  3656 
  3657 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3658 and `goalw': the theory is no longer needed as an explicit argument -
  3659 the current theory context is used; assumptions are no longer returned
  3660 at the ML-level unless one of them starts with ==> or !!; it is
  3661 recommended to convert to these new commands using isatool fixgoal
  3662 (backup your sources first!);
  3663 
  3664 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3665 the current theory context, and 'theory' to lookup stored theories;
  3666 
  3667 * new theory section 'locale' for declaring constants, assumptions and
  3668 definitions that have local scope;
  3669 
  3670 * new theory section 'nonterminals' for purely syntactic types;
  3671 
  3672 * new theory section 'setup' for generic ML setup functions
  3673 (e.g. package initialization);
  3674 
  3675 * the distribution now includes Isabelle icons: see
  3676 lib/logo/isabelle-{small,tiny}.xpm;
  3677 
  3678 * isatool install - install binaries with absolute references to
  3679 ISABELLE_HOME/bin;
  3680 
  3681 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3682 
  3683 * print mode 'emacs' reserved for Isamode;
  3684 
  3685 * support multiple print (ast) translations per constant name;
  3686 
  3687 * theorems involving oracles are now printed with a suffixed [!];
  3688 
  3689 
  3690 *** HOL ***
  3691 
  3692 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3693 
  3694 * HOL/inductive package reorganized and improved: now supports mutual
  3695 definitions such as
  3696 
  3697   inductive EVEN ODD
  3698     intrs
  3699       null "0 : EVEN"
  3700       oddI "n : EVEN ==> Suc n : ODD"
  3701       evenI "n : ODD ==> Suc n : EVEN"
  3702 
  3703 new theorem list "elims" contains an elimination rule for each of the
  3704 recursive sets; inductive definitions now handle disjunctive premises
  3705 correctly (also ZF);
  3706 
  3707 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3708 "mutual_induct" no longer exists - the induction rule is always
  3709 contained in "induct";
  3710 
  3711 
  3712 * HOL/datatype package re-implemented and greatly improved: now
  3713 supports mutually recursive datatypes such as
  3714 
  3715   datatype
  3716     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3717             | SUM ('a aexp) ('a aexp)
  3718             | DIFF ('a aexp) ('a aexp)
  3719             | NUM 'a
  3720   and
  3721     'a bexp = LESS ('a aexp) ('a aexp)
  3722             | AND ('a bexp) ('a bexp)
  3723             | OR ('a bexp) ('a bexp)
  3724 
  3725 as well as indirectly recursive datatypes such as
  3726 
  3727   datatype
  3728     ('a, 'b) term = Var 'a
  3729                   | App 'b ((('a, 'b) term) list)
  3730 
  3731 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  3732 induction on mutually / indirectly recursive datatypes.
  3733 
  3734 Primrec equations are now stored in theory and can be accessed via
  3735 <function_name>.simps.
  3736 
  3737 INCOMPATIBILITIES:
  3738 
  3739   - Theories using datatypes must now have theory Datatype as an
  3740     ancestor.
  3741   - The specific <typename>.induct_tac no longer exists - use the
  3742     generic induct_tac instead.
  3743   - natE has been renamed to nat.exhaust - use exhaust_tac
  3744     instead of res_inst_tac ... natE. Note that the variable
  3745     names in nat.exhaust differ from the names in natE, this
  3746     may cause some "fragile" proofs to fail.
  3747   - The theorems split_<typename>_case and split_<typename>_case_asm
  3748     have been renamed to <typename>.split and <typename>.split_asm.
  3749   - Since default sorts of type variables are now handled correctly,
  3750     some datatype definitions may have to be annotated with explicit
  3751     sort constraints.
  3752   - Primrec definitions no longer require function name and type
  3753     of recursive argument.
  3754 
  3755 Consider using isatool fixdatatype to adapt your theories and proof
  3756 scripts to the new package (backup your sources first!).
  3757 
  3758 
  3759 * HOL/record package: considerably improved implementation; now
  3760 includes concrete syntax for record types, terms, updates; theorems
  3761 for surjective pairing and splitting !!-bound record variables; proof
  3762 support is as follows:
  3763 
  3764   1) standard conversions (selectors or updates applied to record
  3765 constructor terms) are part of the standard simpset;
  3766 
  3767   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  3768 made part of standard simpset and claset via addIffs;
  3769 
  3770   3) a tactic for record field splitting (record_split_tac) is part of
  3771 the standard claset (addSWrapper);
  3772 
  3773 To get a better idea about these rules you may retrieve them via
  3774 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  3775 the name of your record type.
  3776 
  3777 The split tactic 3) conceptually simplifies by the following rule:
  3778 
  3779   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  3780 
  3781 Thus any record variable that is bound by meta-all will automatically
  3782 blow up into some record constructor term, consequently the
  3783 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  3784 solve record problems automatically.
  3785 
  3786 
  3787 * reorganized the main HOL image: HOL/Integ and String loaded by
  3788 default; theory Main includes everything;
  3789 
  3790 * automatic simplification of integer sums and comparisons, using cancellation;
  3791 
  3792 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  3793 
  3794 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  3795 
  3796 * many new identities for unions, intersections, set difference, etc.;
  3797 
  3798 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  3799 called split_if, split_split, split_sum_case and split_nat_case (to go
  3800 with add/delsplits);
  3801 
  3802 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  3803 (?x::unit) = (); this is made part of the default simpset, which COULD
  3804 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  3805 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  3806 unit_abs_eta_conv is added in order to counter the effect of
  3807 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  3808 %u.f();
  3809 
  3810 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3811 makes more sense);
  3812 
  3813 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3814   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3815   disjointness reasoning but breaking a few old proofs.
  3816 
  3817 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3818 to 'converse' from 'inverse' (for compatibility with ZF and some
  3819 literature);
  3820 
  3821 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3822 the well-founded relation;
  3823 
  3824 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3825     Compl A.  The "Compl" syntax remains available as input syntax for this
  3826     release ONLY.
  3827 
  3828 * HOL/Update: new theory of function updates:
  3829     f(a:=b) == %x. if x=a then b else f x
  3830 may also be iterated as in f(a:=b,c:=d,...);
  3831 
  3832 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  3833 
  3834 * HOL/List:
  3835   - new function list_update written xs[i:=v] that updates the i-th
  3836     list position. May also be iterated as in xs[i:=a,j:=b,...].
  3837   - new function `upt' written [i..j(] which generates the list
  3838     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  3839     bound write [i..j], which is a shorthand for [i..j+1(].
  3840   - new lexicographic orderings and corresponding wellfoundedness theorems.
  3841 
  3842 * HOL/Arith:
  3843   - removed 'pred' (predecessor) function;
  3844   - generalized some theorems about n-1;
  3845   - many new laws about "div" and "mod";
  3846   - new laws about greatest common divisors (see theory ex/Primes);
  3847 
  3848 * HOL/Relation: renamed the relational operator r^-1 "converse"
  3849 instead of "inverse";
  3850 
  3851 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  3852   of the multiset ordering;
  3853 
  3854 * directory HOL/Real: a construction of the reals using Dedekind cuts
  3855   (not included by default);
  3856 
  3857 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  3858 
  3859 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  3860   programs, i.e. different program variables may have different types.
  3861 
  3862 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3863   [previously, this check worked only if the rewrite rule was unconditional]
  3864   Now rew can involve either definitions or equalities (either == or =).
  3865 
  3866 
  3867 *** ZF ***
  3868 
  3869 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  3870   only the theorems proved on ZF.ML;
  3871 
  3872 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3873   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3874   disjointness reasoning but breaking a few old proofs.
  3875 
  3876 * ZF/Update: new theory of function updates
  3877     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  3878   may also be iterated as in f(a:=b,c:=d,...);
  3879 
  3880 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  3881 
  3882 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3883   [previously, this check worked only if the rewrite rule was unconditional]
  3884   Now rew can involve either definitions or equalities (either == or =).
  3885 
  3886 * case_tac provided for compatibility with HOL
  3887     (like the old excluded_middle_tac, but with subgoals swapped)
  3888 
  3889 
  3890 *** Internal programming interfaces ***
  3891 
  3892 * Pure: several new basic modules made available for general use, see
  3893 also src/Pure/README;
  3894 
  3895 * improved the theory data mechanism to support encapsulation (data
  3896 kind name replaced by private Object.kind, acting as authorization
  3897 key); new type-safe user interface via functor TheoryDataFun; generic
  3898 print_data function becomes basically useless;
  3899 
  3900 * removed global_names compatibility flag -- all theory declarations
  3901 are qualified by default;
  3902 
  3903 * module Pure/Syntax now offers quote / antiquote translation
  3904 functions (useful for Hoare logic etc. with implicit dependencies);
  3905 see HOL/ex/Antiquote for an example use;
  3906 
  3907 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  3908 cterm -> thm;
  3909 
  3910 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  3911 subgoal;
  3912 
  3913 * Display.print_goals function moved to Locale.print_goals;
  3914 
  3915 * standard print function for goals supports current_goals_markers
  3916 variable for marking begin of proof, end of proof, start of goal; the
  3917 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  3918 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  3919 for example;
  3920 
  3921 
  3922 
  3923 New in Isabelle98 (January 1998)
  3924 --------------------------------
  3925 
  3926 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3927 
  3928 * changed lexical syntax of terms / types: dots made part of long
  3929 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  3930 
  3931 * simpset (and claset) reference variable replaced by functions
  3932 simpset / simpset_ref;
  3933 
  3934 * no longer supports theory aliases (via merge) and non-trivial
  3935 implicit merge of thms' signatures;
  3936 
  3937 * most internal names of constants changed due to qualified names;
  3938 
  3939 * changed Pure/Sequence interface (see Pure/seq.ML);
  3940 
  3941 
  3942 *** General Changes ***
  3943 
  3944 * hierachically structured name spaces (for consts, types, axms, thms
  3945 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  3946 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  3947 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  3948 long_names for fully qualified output names; NOTE: ML programs
  3949 (special tactics, packages etc.) referring to internal names may have
  3950 to be adapted to cope with fully qualified names; in case of severe
  3951 backward campatibility problems try setting 'global_names' at compile
  3952 time to have enrything declared within a flat name space; one may also
  3953 fine tune name declarations in theories via the 'global' and 'local'
  3954 section;
  3955 
  3956 * reimplemented the implicit simpset and claset using the new anytype
  3957 data filed in signatures; references simpset:simpset ref etc. are
  3958 replaced by functions simpset:unit->simpset and
  3959 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  3960 to patch your ML files accordingly;
  3961 
  3962 * HTML output now includes theory graph data for display with Java
  3963 applet or isatool browser; data generated automatically via isatool
  3964 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  3965 
  3966 * defs may now be conditional; improved rewrite_goals_tac to handle
  3967 conditional equations;
  3968 
  3969 * defs now admits additional type arguments, using TYPE('a) syntax;
  3970 
  3971 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  3972 creates a new theory node; implicit merge of thms' signatures is
  3973 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  3974 transfer:theory->thm->thm in (rare) cases;
  3975 
  3976 * improved handling of draft signatures / theories; draft thms (and
  3977 ctyps, cterms) are automatically promoted to real ones;
  3978 
  3979 * slightly changed interfaces for oracles: admit many per theory, named
  3980 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  3981 
  3982 * print_goals: optional output of const types (set show_consts and
  3983 show_types);
  3984 
  3985 * improved output of warnings (###) and errors (***);
  3986 
  3987 * subgoal_tac displays a warning if the new subgoal has type variables;
  3988 
  3989 * removed old README and Makefiles;
  3990 
  3991 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  3992 
  3993 * removed obsolete init_pps and init_database;
  3994 
  3995 * deleted the obsolete tactical STATE, which was declared by
  3996     fun STATE tacfun st = tacfun st st;
  3997 
  3998 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  3999 (which abbreviates $HOME);
  4000 
  4001 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4002 use isatool fixseq to adapt your ML programs (this works for fully
  4003 qualified references to the Sequence structure only!);
  4004 
  4005 * use_thy no longer requires writable current directory; it always
  4006 reloads .ML *and* .thy file, if either one is out of date;
  4007 
  4008 
  4009 *** Classical Reasoner ***
  4010 
  4011 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4012 tactics that use classical reasoning to simplify a subgoal without
  4013 splitting it into several subgoals;
  4014 
  4015 * Safe_tac: like safe_tac but uses the default claset;
  4016 
  4017 
  4018 *** Simplifier ***
  4019 
  4020 * added simplification meta rules:
  4021     (asm_)(full_)simplify: simpset -> thm -> thm;
  4022 
  4023 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4024 logics (again);
  4025 
  4026 * added prems argument to simplification procedures;
  4027 
  4028 * HOL, FOL, ZF: added infix function `addsplits':
  4029   instead of `<simpset> setloop (split_tac <thms>)'
  4030   you can simply write `<simpset> addsplits <thms>'
  4031 
  4032 
  4033 *** Syntax ***
  4034 
  4035 * TYPE('a) syntax for type reflection terms;
  4036 
  4037 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4038 
  4039 * pretty printer: changed order of mixfix annotation preference (again!);
  4040 
  4041 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4042 
  4043 
  4044 *** HOL ***
  4045 
  4046 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4047   with `addloop' of the simplifier to faciliate case splitting in premises.
  4048 
  4049 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4050 
  4051 * HOL/Auth: new protocol proofs including some for the Internet
  4052   protocol TLS;
  4053 
  4054 * HOL/Map: new theory of `maps' a la VDM;
  4055 
  4056 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4057 cancelling out common nat summands from =, <, <= (in)equalities, or
  4058 differences; simplification procedures nat_cancel_factor for
  4059 cancelling common factor from =, <, <= (in)equalities over natural
  4060 sums; nat_cancel contains both kinds of procedures, it is installed by
  4061 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4062 
  4063 * HOL/simplifier: terms of the form
  4064   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4065   are rewritten to
  4066   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4067   and those of the form
  4068   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4069   are rewritten to
  4070   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4071 
  4072 * HOL/datatype
  4073   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4074 
  4075   P(t_case f1 ... fn x) =
  4076      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4077         ...
  4078        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4079      )
  4080 
  4081   and a theorem `split_t_case_asm' of the form
  4082 
  4083   P(t_case f1 ... fn x) =
  4084     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4085         ...
  4086        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4087      )
  4088   which can be added to a simpset via `addsplits'. The existing theorems
  4089   expand_list_case and expand_option_case have been renamed to
  4090   split_list_case and split_option_case.
  4091 
  4092 * HOL/Arithmetic:
  4093   - `pred n' is automatically converted to `n-1'.
  4094     Users are strongly encouraged not to use `pred' any longer,
  4095     because it will disappear altogether at some point.
  4096   - Users are strongly encouraged to write "0 < n" rather than
  4097     "n ~= 0". Theorems and proof tools have been modified towards this
  4098     `standard'.
  4099 
  4100 * HOL/Lists:
  4101   the function "set_of_list" has been renamed "set" (and its theorems too);
  4102   the function "nth" now takes its arguments in the reverse order and
  4103   has acquired the infix notation "!" as in "xs!n".
  4104 
  4105 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4106 
  4107 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4108   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4109 
  4110 * HOL/record: extensible records with schematic structural subtyping
  4111 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4112 still lacks various theorems and concrete record syntax;
  4113 
  4114 
  4115 *** HOLCF ***
  4116 
  4117 * removed "axioms" and "generated by" sections;
  4118 
  4119 * replaced "ops" section by extended "consts" section, which is capable of
  4120   handling the continuous function space "->" directly;
  4121 
  4122 * domain package:
  4123   . proves theorems immediately and stores them in the theory,
  4124   . creates hierachical name space,
  4125   . now uses normal mixfix annotations (instead of cinfix...),
  4126   . minor changes to some names and values (for consistency),
  4127   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4128   . separator between mutual domain defs: changed "," to "and",
  4129   . improved handling of sort constraints;  now they have to
  4130     appear on the left-hand side of the equations only;
  4131 
  4132 * fixed LAM <x,y,zs>.b syntax;
  4133 
  4134 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4135 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4136 
  4137 
  4138 *** FOL and ZF ***
  4139 
  4140 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4141   with `addloop' of the simplifier to faciliate case splitting in premises.
  4142 
  4143 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4144 in HOL, they strip ALL and --> from proved theorems;
  4145 
  4146 
  4147 
  4148 New in Isabelle94-8 (May 1997)
  4149 ------------------------------
  4150 
  4151 *** General Changes ***
  4152 
  4153 * new utilities to build / run / maintain Isabelle etc. (in parts
  4154 still somewhat experimental); old Makefiles etc. still functional;
  4155 
  4156 * new 'Isabelle System Manual';
  4157 
  4158 * INSTALL text, together with ./configure and ./build scripts;
  4159 
  4160 * reimplemented type inference for greater efficiency, better error
  4161 messages and clean internal interface;
  4162 
  4163 * prlim command for dealing with lots of subgoals (an easier way of
  4164 setting goals_limit);
  4165 
  4166 
  4167 *** Syntax ***
  4168 
  4169 * supports alternative (named) syntax tables (parser and pretty
  4170 printer); internal interface is provided by add_modesyntax(_i);
  4171 
  4172 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4173 be used in conjunction with the Isabelle symbol font; uses the
  4174 "symbols" syntax table;
  4175 
  4176 * added token_translation interface (may translate name tokens in
  4177 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4178 the current print_mode); IMPORTANT: user print translation functions
  4179 are responsible for marking newly introduced bounds
  4180 (Syntax.mark_boundT);
  4181 
  4182 * token translations for modes "xterm" and "xterm_color" that display
  4183 names in bold, underline etc. or colors (which requires a color
  4184 version of xterm);
  4185 
  4186 * infixes may now be declared with names independent of their syntax;
  4187 
  4188 * added typed_print_translation (like print_translation, but may
  4189 access type of constant);
  4190 
  4191 
  4192 *** Classical Reasoner ***
  4193 
  4194 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4195 some limitations.  Blast_tac...
  4196   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4197   + ignores elimination rules that don't have the correct format
  4198         (the conclusion MUST be a formula variable)
  4199   + ignores types, which can make HOL proofs fail
  4200   + rules must not require higher-order unification, e.g. apply_type in ZF
  4201     [message "Function Var's argument not a bound variable" relates to this]
  4202   + its proof strategy is more general but can actually be slower
  4203 
  4204 * substitution with equality assumptions no longer permutes other
  4205 assumptions;
  4206 
  4207 * minor changes in semantics of addafter (now called addaltern); renamed
  4208 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4209 (and access functions for it);
  4210 
  4211 * improved combination of classical reasoner and simplifier:
  4212   + functions for handling clasimpsets
  4213   + improvement of addss: now the simplifier is called _after_ the
  4214     safe steps.
  4215   + safe variant of addss called addSss: uses safe simplifications
  4216     _during_ the safe steps. It is more complete as it allows multiple
  4217     instantiations of unknowns (e.g. with slow_tac).
  4218 
  4219 *** Simplifier ***
  4220 
  4221 * added interface for simplification procedures (functions that
  4222 produce *proven* rewrite rules on the fly, depending on current
  4223 redex);
  4224 
  4225 * ordering on terms as parameter (used for ordered rewriting);
  4226 
  4227 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4228 
  4229 * the solver is now split into a safe and an unsafe part.
  4230 This should be invisible for the normal user, except that the
  4231 functions setsolver and addsolver have been renamed to setSolver and
  4232 addSolver; added safe_asm_full_simp_tac;
  4233 
  4234 
  4235 *** HOL ***
  4236 
  4237 * a generic induction tactic `induct_tac' which works for all datatypes and
  4238 also for type `nat';
  4239 
  4240 * a generic case distinction tactic `exhaust_tac' which works for all
  4241 datatypes and also for type `nat';
  4242 
  4243 * each datatype comes with a function `size';
  4244 
  4245 * patterns in case expressions allow tuple patterns as arguments to
  4246 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4247 
  4248 * primrec now also works with type nat;
  4249 
  4250 * recdef: a new declaration form, allows general recursive functions to be
  4251 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4252 
  4253 * the constant for negation has been renamed from "not" to "Not" to
  4254 harmonize with FOL, ZF, LK, etc.;
  4255 
  4256 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4257 infinite lists;
  4258 
  4259 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4260 
  4261 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4262 problems in commutative rings, using axiomatic type classes for + and *;
  4263 
  4264 * more examples in HOL/MiniML and HOL/Auth;
  4265 
  4266 * more default rewrite rules for quantifiers, union/intersection;
  4267 
  4268 * a new constant `arbitrary == @x.False';
  4269 
  4270 * HOLCF/IOA replaces old HOL/IOA;
  4271 
  4272 * HOLCF changes: derived all rules and arities
  4273   + axiomatic type classes instead of classes
  4274   + typedef instead of faking type definitions
  4275   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4276   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4277   + eliminated the types void, one, tr
  4278   + use unit lift and bool lift (with translations) instead of one and tr
  4279   + eliminated blift from Lift3.thy (use Def instead of blift)
  4280   all eliminated rules are derived as theorems --> no visible changes ;
  4281 
  4282 
  4283 *** ZF ***
  4284 
  4285 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4286 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4287 as ZF_cs addSIs [equalityI];
  4288 
  4289 
  4290 
  4291 New in Isabelle94-7 (November 96)
  4292 ---------------------------------
  4293 
  4294 * allowing negative levels (as offsets) in prlev and choplev;
  4295 
  4296 * super-linear speedup for large simplifications;
  4297 
  4298 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4299 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4300 FAIL); can suppress it using the command Delsimps (ex_simps @
  4301 all_simps); De Morgan laws are also now included, by default;
  4302 
  4303 * improved printing of ==>  :  ~:
  4304 
  4305 * new object-logic "Sequents" adds linear logic, while replacing LK
  4306 and Modal (thanks to Sara Kalvala);
  4307 
  4308 * HOL/Auth: correctness proofs for authentication protocols;
  4309 
  4310 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4311 examples on HOL/Auth);
  4312 
  4313 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4314 the rewriter and classical reasoner simultaneously;
  4315 
  4316 * function uresult no longer returns theorems in "standard" format;
  4317 regain previous version by: val uresult = standard o uresult;
  4318 
  4319 
  4320 
  4321 New in Isabelle94-6
  4322 -------------------
  4323 
  4324 * oracles -- these establish an interface between Isabelle and trusted
  4325 external reasoners, which may deliver results as theorems;
  4326 
  4327 * proof objects (in particular record all uses of oracles);
  4328 
  4329 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4330 
  4331 * "constdefs" section in theory files;
  4332 
  4333 * "primrec" section (HOL) no longer requires names;
  4334 
  4335 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4336 
  4337 
  4338 
  4339 New in Isabelle94-5
  4340 -------------------
  4341 
  4342 * reduced space requirements;
  4343 
  4344 * automatic HTML generation from theories;
  4345 
  4346 * theory files no longer require "..." (quotes) around most types;
  4347 
  4348 * new examples, including two proofs of the Church-Rosser theorem;
  4349 
  4350 * non-curried (1994) version of HOL is no longer distributed;
  4351 
  4352 
  4353 
  4354 New in Isabelle94-4
  4355 -------------------
  4356 
  4357 * greatly reduced space requirements;
  4358 
  4359 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4360 
  4361 * searchable theorem database (see the section "Retrieving theorems" on
  4362 page 8 of the Reference Manual);
  4363 
  4364 * new examples, including Grabczewski's monumental case study of the
  4365 Axiom of Choice;
  4366 
  4367 * The previous version of HOL renamed to Old_HOL;
  4368 
  4369 * The new version of HOL (previously called CHOL) uses a curried syntax
  4370 for functions.  Application looks like f a b instead of f(a,b);
  4371 
  4372 * Mutually recursive inductive definitions finally work in HOL;
  4373 
  4374 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4375 translates to the operator "split";
  4376 
  4377 
  4378 
  4379 New in Isabelle94-3
  4380 -------------------
  4381 
  4382 * new infix operator, addss, allowing the classical reasoner to
  4383 perform simplification at each step of its search.  Example:
  4384         fast_tac (cs addss ss)
  4385 
  4386 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4387 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4388 look like (a,b) instead of <a,b>;
  4389 
  4390 * PLEASE NOTE: CHOL will eventually replace HOL!
  4391 
  4392 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4393 It translates to the operator "split".  A new theory of integers is available;
  4394 
  4395 * In ZF, integer numerals now denote two's-complement binary integers.
  4396 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4397 
  4398 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4399 of the Axiom of Choice;
  4400 
  4401 
  4402 
  4403 New in Isabelle94-2
  4404 -------------------
  4405 
  4406 * Significantly faster resolution;
  4407 
  4408 * the different sections in a .thy file can now be mixed and repeated
  4409 freely;
  4410 
  4411 * Database of theorems for FOL, HOL and ZF.  New
  4412 commands including qed, qed_goal and bind_thm store theorems in the database.
  4413 
  4414 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4415 a given theory (thms_of), or find out what theory a theorem was proved in
  4416 (theory_of_thm);
  4417 
  4418 * Bugs fixed in the inductive definition and datatype packages;
  4419 
  4420 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4421 and HOL_dup_cs obsolete;
  4422 
  4423 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4424 have been removed;
  4425 
  4426 * Simpler definition of function space in ZF;
  4427 
  4428 * new results about cardinal and ordinal arithmetic in ZF;
  4429 
  4430 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4431 types;
  4432 
  4433 
  4434 $Id$