NEWS
author haftmann
Tue Oct 10 13:59:12 2006 +0200 (2006-10-10)
changeset 20950 981fa0ce23ed
parent 20919 dab803075c62
child 20951 868120282837
permissions -rw-r--r--
added IsarAdvanced material
     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 infixes ins ins_string ins_int have been abandoned in favour of insert.
   636 INCOMPATIBILITY: rewrite "x ins(_...) xs" to "insert (op =) x xs"
   637 
   638 * Pure/General/susp.ML:
   639 
   640 New module for delayed evaluations.
   641 
   642 * Pure/library:
   643 
   644 Semantically identical functions "equal_list" and "eq_list" have been
   645 unified to "eq_list".
   646 
   647 * Pure/library:
   648 
   649   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   650   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   651 
   652 The semantics of "burrow" is: "take a function with *simulatanously*
   653 transforms a list of value, and apply it *simulatanously* to a list of
   654 list of values of the appropriate type". Confer this with "map" which
   655 would *not* apply its argument function simulatanously but in
   656 sequence. "fold_burrow" has an additional context.
   657 
   658 Both actually avoid the usage of "unflat" since they hide away
   659 "unflat" from the user.
   660 
   661 * Pure/library: functions map2 and fold2 with curried syntax for
   662 simultanous mapping and folding:
   663 
   664     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   665     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   666 
   667 * Pure/library: indexed lists - some functions in the Isabelle library
   668 treating lists over 'a as finite mappings from [0...n] to 'a have been
   669 given more convenient names and signatures reminiscent of similar
   670 functions for alists, tables, etc:
   671 
   672   val nth: 'a list -> int -> 'a 
   673   val nth_update: int * 'a -> 'a list -> 'a list
   674   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   675   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   676 
   677 Note that fold_index starts counting at index 0, not 1 like foldln
   678 used to.
   679 
   680 * Pure/library: general ``divide_and_conquer'' combinator on lists.
   681 
   682 * Pure/General/name_mangler.ML provides a functor for generic name
   683 mangling (bijective mapping from any expression values to strings).
   684 
   685 * Pure/General/rat.ML implements rational numbers.
   686 
   687 * Pure/General/table.ML: the join operations now works via exceptions
   688 DUP/SAME instead of type option.  This is simpler in simple cases, and
   689 admits slightly more efficient complex applications.
   690 
   691 * Pure: datatype Context.generic joins theory/Proof.context and
   692 provides some facilities for code that works in either kind of
   693 context, notably GenericDataFun for uniform theory and proof data.
   694 
   695 * Pure: 'advanced' translation functions (parse_translation etc.) now
   696 use Context.generic instead of just theory.
   697 
   698 * Pure: simplified internal attribute type, which is now always
   699 Context.generic * thm -> Context.generic * thm.  Global (theory)
   700 vs. local (Proof.context) attributes have been discontinued, while
   701 minimizing code duplication.  Thm.rule_attribute and
   702 Thm.declaration_attribute build canonical attributes; see also
   703 structure Context for further operations on Context.generic, notably
   704 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   705 declarations and definitions.
   706 
   707 * Pure/kernel: consts certification ignores sort constraints given in
   708 signature declarations.  (This information is not relevant to the
   709 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE.
   710 
   711 * Pure: axiomatic type classes are now purely definitional, with
   712 explicit proofs of class axioms and super class relations performed
   713 internally.  See Pure/axclass.ML for the main internal interfaces --
   714 notably AxClass.define_class supercedes AxClass.add_axclass, and
   715 AxClass.axiomatize_class/classrel/arity supercede
   716 Sign.add_classes/classrel/arities.
   717 
   718 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
   719 global/local versions on theory vs. Proof.context have been
   720 discontinued; Attrib.syntax and Method.syntax have been adapted
   721 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
   722 attributes, methods, etc.
   723 
   724 * Pure: several functions of signature "... -> theory -> theory * ..."
   725 have been reoriented to "... -> theory -> ... * theory" in order to
   726 allow natural usage in combination with the ||>, ||>>, |-> and
   727 fold_map combinators.
   728 
   729 * Pure: primitive rule lift_rule now takes goal cterm instead of an
   730 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
   731 achieve the old behaviour.
   732 
   733 * Pure: the "Goal" constant is now called "prop", supporting a
   734 slightly more general idea of ``protecting'' meta-level rule
   735 statements.
   736 
   737 * Pure: Logic.(un)varify only works in a global context, which is now
   738 enforced instead of silently assumed.  INCOMPATIBILITY, may use
   739 Logic.legacy_(un)varify as temporary workaround.
   740 
   741 * Pure: structure Name provides scalable operations for generating
   742 internal variable names, notably Name.variants etc.  This replaces
   743 some popular functions from term.ML:
   744 
   745   Term.variant		->  Name.variant
   746   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
   747   Term.invent_names	->  Name.invent_list
   748 
   749 Note that low-level renaming rarely occurs in new code -- operations
   750 from structure Variable are used instead (see below).
   751 
   752 * Pure: structure Variable provides fundamental operations for proper
   753 treatment of fixed/schematic variables in a context.  For example,
   754 Variable.import introduces fixes for schematics of given facts and
   755 Variable.export reverses the effect (up to renaming) -- this replaces
   756 various freeze_thaw operations.
   757 
   758 * Pure: structure Goal provides simple interfaces for
   759 init/conclude/finish and tactical prove operations (replacing former
   760 Tactic.prove).  Goal.prove is the canonical way to prove results
   761 within a given context; Goal.prove_global is a degraded version for
   762 theory level goals, including a global Drule.standard.  Note that
   763 OldGoals.prove_goalw_cterm has long been obsolete, since it is
   764 ill-behaved in a local proof context (e.g. with local fixes/assumes or
   765 in a locale context).
   766 
   767 * Isar: simplified treatment of user-level errors, using exception
   768 ERROR of string uniformly.  Function error now merely raises ERROR,
   769 without any side effect on output channels.  The Isar toplevel takes
   770 care of proper display of ERROR exceptions.  ML code may use plain
   771 handle/can/try; cat_error may be used to concatenate errors like this:
   772 
   773   ... handle ERROR msg => cat_error msg "..."
   774 
   775 Toplevel ML code (run directly or through the Isar toplevel) may be
   776 embedded into the Isar toplevel with exception display/debug like
   777 this:
   778 
   779   Isar.toplevel (fn () => ...)
   780 
   781 INCOMPATIBILITY, removed special transform_error facilities, removed
   782 obsolete variants of user-level exceptions (ERROR_MESSAGE,
   783 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
   784 -- use plain ERROR instead.
   785 
   786 * Isar: theory setup now has type (theory -> theory), instead of a
   787 list.  INCOMPATIBILITY, may use #> to compose setup functions.
   788 
   789 * Isar: installed ML toplevel pretty printer for type Proof.context,
   790 subject to ProofContext.debug/verbose flags.
   791 
   792 * Isar: Toplevel.theory_to_proof admits transactions that modify the
   793 theory before entering a proof state.  Transactions now always see a
   794 quasi-functional intermediate checkpoint, both in interactive and
   795 batch mode.
   796 
   797 * Simplifier: the simpset of a running simplification process now
   798 contains a proof context (cf. Simplifier.the_context), which is the
   799 very context that the initial simpset has been retrieved from (by
   800 simpset_of/local_simpset_of).  Consequently, all plug-in components
   801 (solver, looper etc.) may depend on arbitrary proof data.
   802 
   803 * Simplifier.inherit_context inherits the proof context (plus the
   804 local bounds) of the current simplification process; any simproc
   805 etc. that calls the Simplifier recursively should do this!  Removed
   806 former Simplifier.inherit_bounds, which is already included here --
   807 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
   808 specify an explicit context using Simplifier.context/theory_context.
   809 
   810 * Simplifier/Classical Reasoner: more abstract interfaces
   811 change_simpset/claset for modifying the simpset/claset reference of a
   812 theory; raw versions simpset/claset_ref etc. have been discontinued --
   813 INCOMPATIBILITY.
   814 
   815 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
   816 "Trueprop" etc.
   817 
   818 
   819 
   820 New in Isabelle2005 (October 2005)
   821 ----------------------------------
   822 
   823 *** General ***
   824 
   825 * Theory headers: the new header syntax for Isar theories is
   826 
   827   theory <name>
   828   imports <theory1> ... <theoryN>
   829   uses <file1> ... <fileM>
   830   begin
   831 
   832 where the 'uses' part is optional.  The previous syntax
   833 
   834   theory <name> = <theory1> + ... + <theoryN>:
   835 
   836 will disappear in the next release.  Use isatool fixheaders to convert
   837 existing theory files.  Note that there is no change in ancient
   838 non-Isar theories now, but these will disappear soon.
   839 
   840 * Theory loader: parent theories can now also be referred to via
   841 relative and absolute paths.
   842 
   843 * Command 'find_theorems' searches for a list of criteria instead of a
   844 list of constants. Known criteria are: intro, elim, dest, name:string,
   845 simp:term, and any term. Criteria can be preceded by '-' to select
   846 theorems that do not match. Intro, elim, dest select theorems that
   847 match the current goal, name:s selects theorems whose fully qualified
   848 name contain s, and simp:term selects all simplification rules whose
   849 lhs match term.  Any other term is interpreted as pattern and selects
   850 all theorems matching the pattern. Available in ProofGeneral under
   851 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
   852 
   853   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
   854 
   855 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   856 matching the current goal as introduction rule and not having "HOL."
   857 in their name (i.e. not being defined in theory HOL).
   858 
   859 * Command 'thms_containing' has been discontinued in favour of
   860 'find_theorems'; INCOMPATIBILITY.
   861 
   862 * Communication with Proof General is now 8bit clean, which means that
   863 Unicode text in UTF-8 encoding may be used within theory texts (both
   864 formal and informal parts).  Cf. option -U of the Isabelle Proof
   865 General interface.  Here are some simple examples (cf. src/HOL/ex):
   866 
   867   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
   868   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
   869 
   870 * Improved efficiency of the Simplifier and, to a lesser degree, the
   871 Classical Reasoner.  Typical big applications run around 2 times
   872 faster.
   873 
   874 
   875 *** Document preparation ***
   876 
   877 * Commands 'display_drafts' and 'print_drafts' perform simple output
   878 of raw sources.  Only those symbols that do not require additional
   879 LaTeX packages (depending on comments in isabellesym.sty) are
   880 displayed properly, everything else is left verbatim.  isatool display
   881 and isatool print are used as front ends (these are subject to the
   882 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
   883 
   884 * Command tags control specific markup of certain regions of text,
   885 notably folding and hiding.  Predefined tags include "theory" (for
   886 theory begin and end), "proof" for proof commands, and "ML" for
   887 commands involving ML code; the additional tags "visible" and
   888 "invisible" are unused by default.  Users may give explicit tag
   889 specifications in the text, e.g. ''by %invisible (auto)''.  The
   890 interpretation of tags is determined by the LaTeX job during document
   891 preparation: see option -V of isatool usedir, or options -n and -t of
   892 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
   893 \isadroptag.
   894 
   895 Several document versions may be produced at the same time via isatool
   896 usedir (the generated index.html will link all of them).  Typical
   897 specifications include ''-V document=theory,proof,ML'' to present
   898 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
   899 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
   900 these parts without any formal replacement text.  The Isabelle site
   901 default settings produce ''document'' and ''outline'' versions as
   902 specified above.
   903 
   904 * Several new antiquotations:
   905 
   906   @{term_type term} prints a term with its type annotated;
   907 
   908   @{typeof term} prints the type of a term;
   909 
   910   @{const const} is the same as @{term const}, but checks that the
   911   argument is a known logical constant;
   912 
   913   @{term_style style term} and @{thm_style style thm} print a term or
   914   theorem applying a "style" to it
   915 
   916   @{ML text}
   917 
   918 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
   919 definitions, equations, inequations etc., 'concl' printing only the
   920 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
   921 to print the specified premise.  TermStyle.add_style provides an ML
   922 interface for introducing further styles.  See also the "LaTeX Sugar"
   923 document practical applications.  The ML antiquotation prints
   924 type-checked ML expressions verbatim.
   925 
   926 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
   927 and 'text' support optional locale specification '(in loc)', which
   928 specifies the default context for interpreting antiquotations.  For
   929 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
   930 
   931 * Option 'locale=NAME' of antiquotations specifies an alternative
   932 context interpreting the subsequent argument.  For example: @{thm
   933 [locale=lattice] inf_assoc}.
   934 
   935 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
   936 a proof context.
   937 
   938 * Proper output of antiquotations for theory commands involving a
   939 proof context (such as 'locale' or 'theorem (in loc) ...').
   940 
   941 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
   942 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
   943 
   944 * isatool usedir: new option -C (default true) controls whether option
   945 -D should include a copy of the original document directory; -C false
   946 prevents unwanted effects such as copying of administrative CVS data.
   947 
   948 
   949 *** Pure ***
   950 
   951 * Considerably improved version of 'constdefs' command.  Now performs
   952 automatic type-inference of declared constants; additional support for
   953 local structure declarations (cf. locales and HOL records), see also
   954 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
   955 sequential dependencies of definitions within a single 'constdefs'
   956 section; moreover, the declared name needs to be an identifier.  If
   957 all fails, consider to fall back on 'consts' and 'defs' separately.
   958 
   959 * Improved indexed syntax and implicit structures.  First of all,
   960 indexed syntax provides a notational device for subscripted
   961 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
   962 expressions.  Secondly, in a local context with structure
   963 declarations, number indexes \<^sub>n or the empty index (default
   964 number 1) refer to a certain fixed variable implicitly; option
   965 show_structs controls printing of implicit structures.  Typical
   966 applications of these concepts involve record types and locales.
   967 
   968 * New command 'no_syntax' removes grammar declarations (and
   969 translations) resulting from the given syntax specification, which is
   970 interpreted in the same manner as for the 'syntax' command.
   971 
   972 * 'Advanced' translation functions (parse_translation etc.) may depend
   973 on the signature of the theory context being presently used for
   974 parsing/printing, see also isar-ref manual.
   975 
   976 * Improved 'oracle' command provides a type-safe interface to turn an
   977 ML expression of type theory -> T -> term into a primitive rule of
   978 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
   979 is already included here); see also FOL/ex/IffExample.thy;
   980 INCOMPATIBILITY.
   981 
   982 * axclass: name space prefix for class "c" is now "c_class" (was "c"
   983 before); "cI" is no longer bound, use "c.intro" instead.
   984 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
   985 axclasses vs. locales.
   986 
   987 * Improved internal renaming of symbolic identifiers -- attach primes
   988 instead of base 26 numbers.
   989 
   990 * New flag show_question_marks controls printing of leading question
   991 marks in schematic variable names.
   992 
   993 * In schematic variable names, *any* symbol following \<^isub> or
   994 \<^isup> is now treated as part of the base name.  For example, the
   995 following works without printing of awkward ".0" indexes:
   996 
   997   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   998     by simp
   999 
  1000 * Inner syntax includes (*(*nested*) comments*).
  1001 
  1002 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1003 annotations as "(00...)".
  1004 
  1005 * Clear separation of logical types and nonterminals, where the latter
  1006 may only occur in 'syntax' specifications or type abbreviations.
  1007 Before that distinction was only partially implemented via type class
  1008 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1009 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1010 exotic syntax specifications may require further adaption
  1011 (e.g. Cube/Cube.thy).
  1012 
  1013 * Removed obsolete type class "logic", use the top sort {} instead.
  1014 Note that non-logical types should be declared as 'nonterminals'
  1015 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1016 specifications.
  1017 
  1018 * Attributes 'induct' and 'cases': type or set names may now be
  1019 locally fixed variables as well.
  1020 
  1021 * Simplifier: can now control the depth to which conditional rewriting
  1022 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1023 Limit.
  1024 
  1025 * Simplifier: simplification procedures may now take the current
  1026 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1027 interface), which is very useful for calling the Simplifier
  1028 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1029 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1030 low-level mk_simproc no longer applies Logic.varify internally, to
  1031 allow for use in a context of fixed variables.
  1032 
  1033 * thin_tac now works even if the assumption being deleted contains !!
  1034 or ==>.  More generally, erule now works even if the major premise of
  1035 the elimination rule contains !! or ==>.
  1036 
  1037 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1038 
  1039 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1040 from Pure, which contains all common declarations already.  Both
  1041 theories are defined via plain Isabelle/Isar .thy files.
  1042 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1043 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1044 use isatool fixcpure to adapt your theory and ML sources.
  1045 
  1046 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1047 selections of theorems in named facts via index ranges.
  1048 
  1049 * 'print_theorems': in theory mode, really print the difference
  1050 wrt. the last state (works for interactive theory development only),
  1051 in proof mode print all local facts (cf. 'print_facts');
  1052 
  1053 * 'hide': option '(open)' hides only base names.
  1054 
  1055 * More efficient treatment of intermediate checkpoints in interactive
  1056 theory development.
  1057 
  1058 * Code generator is now invoked via code_module (incremental code
  1059 generation) and code_library (modular code generation, ML structures
  1060 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1061 must be quoted when used as identifiers.
  1062 
  1063 * New 'value' command for reading, evaluating and printing terms using
  1064 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1065 quoted when used as identifier.
  1066 
  1067 
  1068 *** Locales ***
  1069 
  1070 * New commands for the interpretation of locale expressions in
  1071 theories (1), locales (2) and proof contexts (3).  These generate
  1072 proof obligations from the expression specification.  After the
  1073 obligations have been discharged, theorems of the expression are added
  1074 to the theory, target locale or proof context.  The synopsis of the
  1075 commands is a follows:
  1076 
  1077   (1) interpretation expr inst
  1078   (2) interpretation target < expr
  1079   (3) interpret expr inst
  1080 
  1081 Interpretation in theories and proof contexts require a parameter
  1082 instantiation of terms from the current context.  This is applied to
  1083 specifications and theorems of the interpreted expression.
  1084 Interpretation in locales only permits parameter renaming through the
  1085 locale expression.  Interpretation is smart in that interpretations
  1086 that are active already do not occur in proof obligations, neither are
  1087 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1088 inspect active interpretations of a particular locale.  For details,
  1089 see the Isar Reference manual.  Examples can be found in
  1090 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1091 
  1092 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1093 'interpret' instead.
  1094 
  1095 * New context element 'constrains' for adding type constraints to
  1096 parameters.
  1097 
  1098 * Context expressions: renaming of parameters with syntax
  1099 redeclaration.
  1100 
  1101 * Locale declaration: 'includes' disallowed.
  1102 
  1103 * Proper static binding of attribute syntax -- i.e. types / terms /
  1104 facts mentioned as arguments are always those of the locale definition
  1105 context, independently of the context of later invocations.  Moreover,
  1106 locale operations (renaming and type / term instantiation) are applied
  1107 to attribute arguments as expected.
  1108 
  1109 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1110 actual attributes; rare situations may require Attrib.attribute to
  1111 embed those attributes into Attrib.src that lack concrete syntax.
  1112 Attribute implementations need to cooperate properly with the static
  1113 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1114 Attrib.XXX_thm etc. already do the right thing without further
  1115 intervention.  Only unusual applications -- such as "where" or "of"
  1116 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1117 on the context and the facts involved -- may have to assign parsed
  1118 values to argument tokens explicitly.
  1119 
  1120 * Changed parameter management in theorem generation for long goal
  1121 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1122 theorem statement in rare situations.
  1123 
  1124 * Locale inspection command 'print_locale' omits notes elements.  Use
  1125 'print_locale!' to have them included in the output.
  1126 
  1127 
  1128 *** Provers ***
  1129 
  1130 * Provers/hypsubst.ML: improved version of the subst method, for
  1131 single-step rewriting: it now works in bound variable contexts. New is
  1132 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1133 rewrite a different subterm than the original subst method, which is
  1134 still available as 'simplesubst'.
  1135 
  1136 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1137 and quasi orders.
  1138 
  1139 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1140 reflexive-transitive closure of relations.
  1141 
  1142 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1143 limit (previously hard-coded with a value of 20) user-definable.
  1144 
  1145 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1146 is peformed already.  Object-logics merely need to finish their
  1147 initial simpset configuration as before.  INCOMPATIBILITY.
  1148 
  1149 
  1150 *** HOL ***
  1151 
  1152 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1153 
  1154   syntax (epsilon)
  1155     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1156 
  1157 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1158 and x-symbol; use option '-m epsilon' to get it actually printed.
  1159 Moreover, the mathematically important symbolic identifier \<epsilon>
  1160 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1161 
  1162 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1163 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1164 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1165 support corresponding Isar calculations.
  1166 
  1167 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1168 instead of ":".
  1169 
  1170 * theory SetInterval: changed the syntax for open intervals:
  1171 
  1172   Old       New
  1173   {..n(}    {..<n}
  1174   {)n..}    {n<..}
  1175   {m..n(}   {m..<n}
  1176   {)m..n}   {m<..n}
  1177   {)m..n(}  {m<..<n}
  1178 
  1179 The old syntax is still supported but will disappear in the next
  1180 release.  For conversion use the following Emacs search and replace
  1181 patterns (these are not perfect but work quite well):
  1182 
  1183   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1184   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1185 
  1186 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1187 equalities in commutative rings; method 'algebra' provides a generic
  1188 interface.
  1189 
  1190 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1191 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1192 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1193 be a tuple pattern.
  1194 
  1195 Some new syntax forms are available:
  1196 
  1197   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1198   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1199   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1200   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1201 
  1202 The latter form "\<Sum>x < k. e" used to be based on a separate
  1203 function "Summation", which has been discontinued.
  1204 
  1205 * theory Finite_Set: in structured induction proofs, the insert case
  1206 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1207 (insert F x)'.
  1208 
  1209 * The 'refute' command has been extended to support a much larger
  1210 fragment of HOL, including axiomatic type classes, constdefs and
  1211 typedefs, inductive datatypes and recursion.
  1212 
  1213 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1214 Requires zChaff with proof generation to be installed.  See
  1215 HOL/ex/SAT_Examples.thy for examples.
  1216 
  1217 * Datatype induction via method 'induct' now preserves the name of the
  1218 induction variable. For example, when proving P(xs::'a list) by
  1219 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1220 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1221 in unstructured proof scripts.
  1222 
  1223 * Reworked implementation of records.  Improved scalability for
  1224 records with many fields, avoiding performance problems for type
  1225 inference. Records are no longer composed of nested field types, but
  1226 of nested extension types. Therefore the record type only grows linear
  1227 in the number of extensions and not in the number of fields.  The
  1228 top-level (users) view on records is preserved.  Potential
  1229 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1230 old record representation. The type generated for a record is called
  1231 <record_name>_ext_type.
  1232 
  1233 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1234 proofs triggered by a record definition or a simproc (if
  1235 quick_and_dirty is enabled).  Definitions of large records can take
  1236 quite long.
  1237 
  1238 New simproc record_upd_simproc for simplification of multiple record
  1239 updates enabled by default.  Moreover, trivial updates are also
  1240 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1241 occasionally, since simplification is more powerful by default.
  1242 
  1243 * typedef: proper support for polymorphic sets, which contain extra
  1244 type-variables in the term.
  1245 
  1246 * Simplifier: automatically reasons about transitivity chains
  1247 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1248 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1249 old proofs break occasionally as simplification may now solve more
  1250 goals than previously.
  1251 
  1252 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1253 present.  Works for all partial orders (class "order"), in particular
  1254 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1255 just like y <= x.
  1256 
  1257 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1258 bound variable or a constant then the let is unfolded.  Otherwise
  1259 first a is simplified to b, and then f b is simplified to g. If
  1260 possible we abstract b from g arriving at "let x = b in h x",
  1261 otherwise we unfold the let and arrive at g.  The simproc can be
  1262 enabled/disabled by the reference use_let_simproc.  Potential
  1263 INCOMPATIBILITY since simplification is more powerful by default.
  1264 
  1265 * Classical reasoning: the meson method now accepts theorems as arguments.
  1266 
  1267 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1268 jobs to provide advice on the provability of subgoals.
  1269 
  1270 * Theory OrderedGroup and Ring_and_Field: various additions and
  1271 improvements to faciliate calculations involving equalities and
  1272 inequalities.
  1273 
  1274 The following theorems have been eliminated or modified
  1275 (INCOMPATIBILITY):
  1276 
  1277   abs_eq             now named abs_of_nonneg
  1278   abs_of_ge_0        now named abs_of_nonneg
  1279   abs_minus_eq       now named abs_of_nonpos
  1280   imp_abs_id         now named abs_of_nonneg
  1281   imp_abs_neg_id     now named abs_of_nonpos
  1282   mult_pos           now named mult_pos_pos
  1283   mult_pos_le        now named mult_nonneg_nonneg
  1284   mult_pos_neg_le    now named mult_nonneg_nonpos
  1285   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1286   mult_neg           now named mult_neg_neg
  1287   mult_neg_le        now named mult_nonpos_nonpos
  1288 
  1289 * Theory Parity: added rules for simplifying exponents.
  1290 
  1291 * Theory List:
  1292 
  1293 The following theorems have been eliminated or modified
  1294 (INCOMPATIBILITY):
  1295 
  1296   list_all_Nil       now named list_all.simps(1)
  1297   list_all_Cons      now named list_all.simps(2)
  1298   list_all_conv      now named list_all_iff
  1299   set_mem_eq         now named mem_iff
  1300 
  1301 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1302 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1303 
  1304 
  1305 *** HOL-Complex ***
  1306 
  1307 * Theory RealDef: better support for embedding natural numbers and
  1308 integers in the reals.
  1309 
  1310 The following theorems have been eliminated or modified
  1311 (INCOMPATIBILITY):
  1312 
  1313   exp_ge_add_one_self  now requires no hypotheses
  1314   real_of_int_add      reversed direction of equality (use [symmetric])
  1315   real_of_int_minus    reversed direction of equality (use [symmetric])
  1316   real_of_int_diff     reversed direction of equality (use [symmetric])
  1317   real_of_int_mult     reversed direction of equality (use [symmetric])
  1318 
  1319 * Theory RComplete: expanded support for floor and ceiling functions.
  1320 
  1321 * Theory Ln is new, with properties of the natural logarithm
  1322 
  1323 * Hyperreal: There is a new type constructor "star" for making
  1324 nonstandard types.  The old type names are now type synonyms:
  1325 
  1326   hypreal = real star
  1327   hypnat = nat star
  1328   hcomplex = complex star
  1329 
  1330 * Hyperreal: Many groups of similarly-defined constants have been
  1331 replaced by polymorphic versions (INCOMPATIBILITY):
  1332 
  1333   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1334 
  1335   starset      <-- starsetNat, starsetC
  1336   *s*          <-- *sNat*, *sc*
  1337   starset_n    <-- starsetNat_n, starsetC_n
  1338   *sn*         <-- *sNatn*, *scn*
  1339   InternalSets <-- InternalNatSets, InternalCSets
  1340 
  1341   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1342   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1343   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1344   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1345   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1346 
  1347 * Hyperreal: Many type-specific theorems have been removed in favor of
  1348 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1349 
  1350   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1351   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1352   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1353   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1354   right_minus <-- hypreal_add_minus
  1355   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1356   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1357   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1358   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1359   mult_1_right <-- hcomplex_mult_one_right
  1360   mult_zero_left <-- hcomplex_mult_zero_left
  1361   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1362   right_distrib <-- hypnat_add_mult_distrib2
  1363   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1364   right_inverse <-- hypreal_mult_inverse
  1365   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1366   order_refl <-- {hypreal,hypnat}_le_refl
  1367   order_trans <-- {hypreal,hypnat}_le_trans
  1368   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1369   order_less_le <-- {hypreal,hypnat}_less_le
  1370   linorder_linear <-- {hypreal,hypnat}_le_linear
  1371   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1372   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1373   add_nonneg_nonneg <-- hypreal_le_add_order
  1374 
  1375 * Hyperreal: Separate theorems having to do with type-specific
  1376 versions of constants have been merged into theorems that apply to the
  1377 new polymorphic constants (INCOMPATIBILITY):
  1378 
  1379   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1380   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1381   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1382   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1383   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1384   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1385   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1386   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1387   STAR_diff <-- {STAR,STARC}_diff
  1388   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1389     STARC_hcomplex_of_complex}_image_subset
  1390   starset_n_Un <-- starset{Nat,C}_n_Un
  1391   starset_n_Int <-- starset{Nat,C}_n_Int
  1392   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1393   starset_n_diff <-- starset{Nat,C}_n_diff
  1394   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1395   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1396   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1397   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1398   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1399   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1400   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1401   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1402   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1403   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1404   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1405   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1406   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1407   starfun_diff <-- starfun{C,RC,CR}_diff
  1408   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1409   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1410   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1411   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1412   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1413   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1414   starfun_Id <-- starfunC_Id
  1415   starfun_approx <-- starfun{Nat,CR}_approx
  1416   starfun_capprox <-- starfun{C,RC}_capprox
  1417   starfun_abs <-- starfunNat_rabs
  1418   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1419   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1420   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1421   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1422   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1423   starfun_add_approx <-- starfunCR_add_approx
  1424   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1425   starfun_divide <-- starfun{C,CR,RC}_divide
  1426   starfun_n <-- starfun{Nat,C}_n
  1427   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1428   starfun_n_add <-- starfun{Nat,C}_n_add
  1429   starfun_n_add_minus <-- starfunNat_n_add_minus
  1430   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1431   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1432   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1433 
  1434   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1435   star_n_minus <-- {hypreal,hcomplex}_minus
  1436   star_n_diff <-- {hypreal,hcomplex}_diff
  1437   star_n_mult <-- {hypreal,hcomplex}_mult
  1438   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1439   star_n_le <-- {hypreal,hypnat}_le
  1440   star_n_less <-- {hypreal,hypnat}_less
  1441   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1442   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1443   star_n_abs <-- hypreal_hrabs
  1444   star_n_divide <-- hcomplex_divide
  1445 
  1446   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1447   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1448   star_of_diff <-- hypreal_of_real_diff
  1449   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1450   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1451   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1452   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1453   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1454   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1455   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1456   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1457   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1458   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1459   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1460   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1461   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1462   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1463   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1464   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1465   star_of_power <-- hypreal_of_real_power
  1466   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1467 
  1468 * Hyperreal: new method "transfer" that implements the transfer
  1469 principle of nonstandard analysis. With a subgoal that mentions
  1470 nonstandard types like "'a star", the command "apply transfer"
  1471 replaces it with an equivalent one that mentions only standard types.
  1472 To be successful, all free variables must have standard types; non-
  1473 standard variables must have explicit universal quantifiers.
  1474 
  1475 * Hyperreal: A theory of Taylor series.
  1476 
  1477 
  1478 *** HOLCF ***
  1479 
  1480 * Discontinued special version of 'constdefs' (which used to support
  1481 continuous functions) in favor of the general Pure one with full
  1482 type-inference.
  1483 
  1484 * New simplification procedure for solving continuity conditions; it
  1485 is much faster on terms with many nested lambda abstractions (cubic
  1486 instead of exponential time).
  1487 
  1488 * New syntax for domain package: selector names are now optional.
  1489 Parentheses should be omitted unless argument is lazy, for example:
  1490 
  1491   domain 'a stream = cons "'a" (lazy "'a stream")
  1492 
  1493 * New command 'fixrec' for defining recursive functions with pattern
  1494 matching; defining multiple functions with mutual recursion is also
  1495 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1496 sinr, or any data constructor defined by the domain package. The given
  1497 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1498 syntax and examples.
  1499 
  1500 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1501 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1502 but the proof obligation additionally includes an admissibility
  1503 requirement. The packages generate instances of class cpo or pcpo,
  1504 with continuity and strictness theorems for Rep and Abs.
  1505 
  1506 * HOLCF: Many theorems have been renamed according to a more standard naming
  1507 scheme (INCOMPATIBILITY):
  1508 
  1509   foo_inject:  "foo$x = foo$y ==> x = y"
  1510   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1511   foo_less:    "(foo$x << foo$y) = (x << y)"
  1512   foo_strict:  "foo$UU = UU"
  1513   foo_defined: "... ==> foo$x ~= UU"
  1514   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1515 
  1516 
  1517 *** ZF ***
  1518 
  1519 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1520 including the First Isomorphism Theorem (on quotienting by the kernel
  1521 of a homomorphism).
  1522 
  1523 * ZF/Simplifier: install second copy of type solver that actually
  1524 makes use of TC rules declared to Isar proof contexts (or locales);
  1525 the old version is still required for ML proof scripts.
  1526 
  1527 
  1528 *** Cube ***
  1529 
  1530 * Converted to Isar theory format; use locales instead of axiomatic
  1531 theories.
  1532 
  1533 
  1534 *** ML ***
  1535 
  1536 * Pure/library.ML no longer defines its own option datatype, but uses
  1537 that of the SML basis, which has constructors NONE and SOME instead of
  1538 None and Some, as well as exception Option.Option instead of OPTION.
  1539 The functions the, if_none, is_some, is_none have been adapted
  1540 accordingly, while Option.map replaces apsome.
  1541 
  1542 * Pure/library.ML: the exception LIST has been given up in favour of
  1543 the standard exceptions Empty and Subscript, as well as
  1544 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1545 superceded by the standard hd and tl functions etc.
  1546 
  1547 A number of basic list functions are no longer exported to the ML
  1548 toplevel, as they are variants of predefined functions.  The following
  1549 suggests how one can translate existing code:
  1550 
  1551     rev_append xs ys = List.revAppend (xs, ys)
  1552     nth_elem (i, xs) = List.nth (xs, i)
  1553     last_elem xs = List.last xs
  1554     flat xss = List.concat xss
  1555     seq fs = List.app fs
  1556     partition P xs = List.partition P xs
  1557     mapfilter f xs = List.mapPartial f xs
  1558 
  1559 * Pure/library.ML: several combinators for linear functional
  1560 transformations, notably reverse application and composition:
  1561 
  1562   x |> f                f #> g
  1563   (x, y) |-> f          f #-> g
  1564 
  1565 * Pure/library.ML: introduced/changed precedence of infix operators:
  1566 
  1567   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1568   infix 2 ?;
  1569   infix 3 o oo ooo oooo;
  1570   infix 4 ~~ upto downto;
  1571 
  1572 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1573 infix operators.
  1574 
  1575 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1576 fold_map support linear functional transformations and nesting.  For
  1577 example:
  1578 
  1579   fold f [x1, ..., xN] y =
  1580     y |> f x1 |> ... |> f xN
  1581 
  1582   (fold o fold) f [xs1, ..., xsN] y =
  1583     y |> fold f xs1 |> ... |> fold f xsN
  1584 
  1585   fold f [x1, ..., xN] =
  1586     f x1 #> ... #> f xN
  1587 
  1588   (fold o fold) f [xs1, ..., xsN] =
  1589     fold f xs1 #> ... #> fold f xsN
  1590 
  1591 * Pure/library.ML: the following selectors on type 'a option are
  1592 available:
  1593 
  1594   the:               'a option -> 'a  (*partial*)
  1595   these:             'a option -> 'a  where 'a = 'b list
  1596   the_default: 'a -> 'a option -> 'a
  1597   the_list:          'a option -> 'a list
  1598 
  1599 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1600 basic operations for association lists, following natural argument
  1601 order; moreover the explicit equality predicate passed here avoids
  1602 potentially expensive polymorphic runtime equality checks.
  1603 The old functions may be expressed as follows:
  1604 
  1605   assoc = uncurry (AList.lookup (op =))
  1606   assocs = these oo AList.lookup (op =)
  1607   overwrite = uncurry (AList.update (op =)) o swap
  1608 
  1609 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1610 
  1611   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1612   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1613 
  1614 replacing make_keylist and keyfilter (occassionally used)
  1615 Naive rewrites:
  1616 
  1617   make_keylist = AList.make
  1618   keyfilter = AList.find (op =)
  1619 
  1620 * eq_fst and eq_snd now take explicit equality parameter, thus
  1621   avoiding eqtypes. Naive rewrites:
  1622 
  1623     eq_fst = eq_fst (op =)
  1624     eq_snd = eq_snd (op =)
  1625 
  1626 * Removed deprecated apl and apr (rarely used).
  1627   Naive rewrites:
  1628 
  1629     apl (n, op) =>>= curry op n
  1630     apr (op, m) =>>= fn n => op (n, m)
  1631 
  1632 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1633 provides a reasonably efficient light-weight implementation of sets as
  1634 lists.
  1635 
  1636 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1637 few new operations; existing lookup and update are now curried to
  1638 follow natural argument order (for use with fold etc.);
  1639 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1640 
  1641 * Pure/General: output via the Isabelle channels of
  1642 writeln/warning/error etc. is now passed through Output.output, with a
  1643 hook for arbitrary transformations depending on the print_mode
  1644 (cf. Output.add_mode -- the first active mode that provides a output
  1645 function wins).  Already formatted output may be embedded into further
  1646 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1647 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1648 accommodate easy composition of diagnostic messages etc.  Programmers
  1649 rarely need to care about Output.output or Output.raw at all, with
  1650 some notable exceptions: Output.output is required when bypassing the
  1651 standard channels (writeln etc.), or in token translations to produce
  1652 properly formatted results; Output.raw is required when capturing
  1653 already output material that will eventually be presented to the user
  1654 a second time.  For the default print mode, both Output.output and
  1655 Output.raw have no effect.
  1656 
  1657 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1658 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1659 cumulative results are displayed at the end of a batch session.
  1660 
  1661 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1662 replaced by File.platform_path and File.shell_path (with appropriate
  1663 hooks).  This provides a clean interface for unusual systems where the
  1664 internal and external process view of file names are different.
  1665 
  1666 * Pure: more efficient orders for basic syntactic entities: added
  1667 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1668 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1669 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1670 orders now -- potential INCOMPATIBILITY for code that depends on a
  1671 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1672 Library.sort_strings on result).
  1673 
  1674 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1675 fold_types traverse types/terms from left to right, observing natural
  1676 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1677 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1678 
  1679 * Pure: name spaces have been refined, with significant changes of the
  1680 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1681 to extern(_table).  The plain name entry path is superceded by a
  1682 general 'naming' context, which also includes the 'policy' to produce
  1683 a fully qualified name and external accesses of a fully qualified
  1684 name; NameSpace.extend is superceded by context dependent
  1685 Sign.declare_name.  Several theory and proof context operations modify
  1686 the naming context.  Especially note Theory.restore_naming and
  1687 ProofContext.restore_naming to get back to a sane state; note that
  1688 Theory.add_path is no longer sufficient to recover from
  1689 Theory.absolute_path in particular.
  1690 
  1691 * Pure: new flags short_names (default false) and unique_names
  1692 (default true) for controlling output of qualified names.  If
  1693 short_names is set, names are printed unqualified.  If unique_names is
  1694 reset, the name prefix is reduced to the minimum required to achieve
  1695 the original result when interning again, even if there is an overlap
  1696 with earlier declarations.
  1697 
  1698 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1699 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1700 (useful for printing error messages).  INCOMPATIBILITY.
  1701 
  1702 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1703 Theory.theory are now identified, referring to the universal
  1704 Context.theory (see Pure/context.ML).  Actual signature and theory
  1705 content is managed as theory data.  The old code and interfaces were
  1706 spread over many files and structures; the new arrangement introduces
  1707 considerable INCOMPATIBILITY to gain more clarity:
  1708 
  1709   Context -- theory management operations (name, identity, inclusion,
  1710     parents, ancestors, merge, etc.), plus generic theory data;
  1711 
  1712   Sign -- logical signature and syntax operations (declaring consts,
  1713     types, etc.), plus certify/read for common entities;
  1714 
  1715   Theory -- logical theory operations (stating axioms, definitions,
  1716     oracles), plus a copy of logical signature operations (consts,
  1717     types, etc.); also a few basic management operations (Theory.copy,
  1718     Theory.merge, etc.)
  1719 
  1720 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  1721 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  1722 for convenience -- they merely return the theory.
  1723 
  1724 * Pure: type Type.tsig is superceded by theory in most interfaces.
  1725 
  1726 * Pure: the Isar proof context type is already defined early in Pure
  1727 as Context.proof (note that ProofContext.context and Proof.context are
  1728 aliases, where the latter is the preferred name).  This enables other
  1729 Isabelle components to refer to that type even before Isar is present.
  1730 
  1731 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  1732 typeK, constK, axiomK, oracleK), but provide explicit operations for
  1733 any of these kinds.  For example, Sign.intern typeK is now
  1734 Sign.intern_type, Theory.hide_space Sign.typeK is now
  1735 Theory.hide_types.  Also note that former
  1736 Theory.hide_classes/types/consts are now
  1737 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  1738 internalize their arguments!  INCOMPATIBILITY.
  1739 
  1740 * Pure: get_thm interface (of PureThy and ProofContext) expects
  1741 datatype thmref (with constructors Name and NameSelection) instead of
  1742 plain string -- INCOMPATIBILITY;
  1743 
  1744 * Pure: cases produced by proof methods specify options, where NONE
  1745 means to remove case bindings -- INCOMPATIBILITY in
  1746 (RAW_)METHOD_CASES.
  1747 
  1748 * Pure: the following operations retrieve axioms or theorems from a
  1749 theory node or theory hierarchy, respectively:
  1750 
  1751   Theory.axioms_of: theory -> (string * term) list
  1752   Theory.all_axioms_of: theory -> (string * term) list
  1753   PureThy.thms_of: theory -> (string * thm) list
  1754   PureThy.all_thms_of: theory -> (string * thm) list
  1755 
  1756 * Pure: print_tac now outputs the goal through the trace channel.
  1757 
  1758 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  1759 Reference Toplevel.debug (default false) controls detailed printing
  1760 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  1761 controls execution profiling -- set to 1 for time and 2 for space
  1762 (both increase the runtime).
  1763 
  1764 * Isar session: The initial use of ROOT.ML is now always timed,
  1765 i.e. the log will show the actual process times, in contrast to the
  1766 elapsed wall-clock time that the outer shell wrapper produces.
  1767 
  1768 * Simplifier: improved handling of bound variables (nameless
  1769 representation, avoid allocating new strings).  Simprocs that invoke
  1770 the Simplifier recursively should use Simplifier.inherit_bounds to
  1771 avoid local name clashes.  Failure to do so produces warnings
  1772 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  1773 for further details.
  1774 
  1775 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  1776 bindings for all theorems stored within a given theory; this may help
  1777 in porting non-Isar theories to Isar ones, while keeping ML proof
  1778 scripts for the time being.
  1779 
  1780 * ML operator HTML.with_charset specifies the charset begin used for
  1781 generated HTML files.  For example:
  1782 
  1783   HTML.with_charset "utf-8" use_thy "Hebrew";
  1784   HTML.with_charset "utf-8" use_thy "Chinese";
  1785 
  1786 
  1787 *** System ***
  1788 
  1789 * Allow symlinks to all proper Isabelle executables (Isabelle,
  1790 isabelle, isatool etc.).
  1791 
  1792 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  1793 isatool doc, isatool mkdir, display_drafts etc.).
  1794 
  1795 * isatool usedir: option -f allows specification of the ML file to be
  1796 used by Isabelle; default is ROOT.ML.
  1797 
  1798 * New isatool version outputs the version identifier of the Isabelle
  1799 distribution being used.
  1800 
  1801 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1802 (containing Boolean satisfiability problems) into Isabelle/HOL
  1803 theories.
  1804 
  1805 
  1806 
  1807 New in Isabelle2004 (April 2004)
  1808 --------------------------------
  1809 
  1810 *** General ***
  1811 
  1812 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1813   Replaces linorder.ML.
  1814 
  1815 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1816   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1817   (\<a>...\<z>), are now considered normal letters, and can therefore
  1818   be used anywhere where an ASCII letter (a...zA...Z) has until
  1819   now. COMPATIBILITY: This obviously changes the parsing of some
  1820   terms, especially where a symbol has been used as a binder, say
  1821   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1822   as an identifier.  Fix it by inserting a space around former
  1823   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1824   existing theory and ML files.
  1825 
  1826 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  1827 
  1828 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  1829   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  1830   a normal (but invisible) letter. For multiple letter subscripts repeat
  1831   \<^isub> like this: x\<^isub>1\<^isub>2.
  1832 
  1833 * Pure: There are now sub-/superscripts that can span more than one
  1834   character. Text between \<^bsub> and \<^esub> is set in subscript in
  1835   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  1836   superscript. The new control characters are not identifier parts.
  1837 
  1838 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  1839   content of "..." to the latex file instead of \isacntrl... . The "..."
  1840   may consist of any printable characters excluding the end bracket >.
  1841 
  1842 * Pure: Using new Isar command "finalconsts" (or the ML functions
  1843   Theory.add_finals or Theory.add_finals_i) it is now possible to
  1844   declare constants "final", which prevents their being given a definition
  1845   later.  It is useful for constants whose behaviour is fixed axiomatically
  1846   rather than definitionally, such as the meta-logic connectives.
  1847 
  1848 * Pure: 'instance' now handles general arities with general sorts
  1849   (i.e. intersections of classes),
  1850 
  1851 * Presentation: generated HTML now uses a CSS style sheet to make layout
  1852   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  1853   It can be changed to alter the colors/layout of generated pages.
  1854 
  1855 
  1856 *** Isar ***
  1857 
  1858 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  1859   cut_tac, subgoal_tac and thin_tac:
  1860   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  1861     locales are no longer forced to write Isar proof scripts.
  1862     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  1863     emulations.
  1864   - INCOMPATIBILITY: names of variables to be instantiated may no
  1865     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  1866     This is consistent with the instantiation attribute "where".
  1867 
  1868 * Attributes "where" and "of":
  1869   - Now take type variables of instantiated theorem into account when reading
  1870     the instantiation string.  This fixes a bug that caused instantiated
  1871     theorems to have too special types in some circumstances.
  1872   - "where" permits explicit instantiations of type variables.
  1873 
  1874 * Calculation commands "moreover" and "also" no longer interfere with
  1875   current facts ("this"), admitting arbitrary combinations with "then"
  1876   and derived forms.
  1877 
  1878 * Locales:
  1879   - Goal statements involving the context element "includes" no longer
  1880     generate theorems with internal delta predicates (those ending on
  1881     "_axioms") in the premise.
  1882     Resolve particular premise with <locale>.intro to obtain old form.
  1883   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  1884     specification and "includes" elements in goal statement.
  1885   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  1886     [intro?] and [elim?] (respectively) by default.
  1887   - Experimental command for instantiation of locales in proof contexts:
  1888         instantiate <label>[<attrs>]: <loc>
  1889     Instantiates locale <loc> and adds all its theorems to the current context
  1890     taking into account their attributes.  Label and attrs are optional
  1891     modifiers, like in theorem declarations.  If present, names of
  1892     instantiated theorems are qualified with <label>, and the attributes
  1893     <attrs> are applied after any attributes these theorems might have already.
  1894       If the locale has assumptions, a chained fact of the form
  1895     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  1896     are derived.  The command does not support old-style locales declared
  1897     with "locale (open)".
  1898       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  1899 
  1900 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  1901   (Isar) contexts.
  1902 
  1903 
  1904 *** HOL ***
  1905 
  1906 * Proof import: new image HOL4 contains the imported library from
  1907   the HOL4 system with about 2500 theorems. It is imported by
  1908   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  1909   can be used like any other Isabelle image.  See
  1910   HOL/Import/HOL/README for more information.
  1911 
  1912 * Simplifier:
  1913   - Much improved handling of linear and partial orders.
  1914     Reasoners for linear and partial orders are set up for type classes
  1915     "linorder" and "order" respectively, and are added to the default simpset
  1916     as solvers.  This means that the simplifier can build transitivity chains
  1917     to solve goals from the assumptions.
  1918   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  1919     of blast or auto after simplification become unnecessary because the goal
  1920     is solved by simplification already.
  1921 
  1922 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  1923     all proved in axiomatic type classes for semirings, rings and fields.
  1924 
  1925 * Numerics:
  1926   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  1927     now formalized using the Ring_and_Field theory mentioned above.
  1928   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  1929     than before, because now they are set up once in a generic manner.
  1930   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  1931     Look for the general versions in Ring_and_Field (and Power if they concern
  1932     exponentiation).
  1933 
  1934 * Type "rat" of the rational numbers is now available in HOL-Complex.
  1935 
  1936 * Records:
  1937   - Record types are now by default printed with their type abbreviation
  1938     instead of the list of all field types. This can be configured via
  1939     the reference "print_record_type_abbr".
  1940   - Simproc "record_upd_simproc" for simplification of multiple updates added
  1941     (not enabled by default).
  1942   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  1943     EX x. x = sel r to True (not enabled by default).
  1944   - Tactic "record_split_simp_tac" to split and simplify records added.
  1945 
  1946 * 'specification' command added, allowing for definition by
  1947   specification.  There is also an 'ax_specification' command that
  1948   introduces the new constants axiomatically.
  1949 
  1950 * arith(_tac) is now able to generate counterexamples for reals as well.
  1951 
  1952 * HOL-Algebra: new locale "ring" for non-commutative rings.
  1953 
  1954 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  1955   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  1956 
  1957 * HOL-Matrix: a first theory for matrices in HOL with an application of
  1958   matrix theory to linear programming.
  1959 
  1960 * Unions and Intersections:
  1961   The latex output syntax of UN and INT has been changed
  1962   from "\Union x \in A. B" to "\Union_{x \in A} B"
  1963   i.e. the index formulae has become a subscript.
  1964   Similarly for "\Union x. B", and for \Inter instead of \Union.
  1965 
  1966 * Unions and Intersections over Intervals:
  1967   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  1968   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  1969   like in normal math, and corresponding versions for < and for intersection.
  1970 
  1971 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  1972   lexicographic dictonary ordering has been added as "lexord".
  1973 
  1974 * ML: the legacy theory structures Int and List have been removed. They had
  1975   conflicted with ML Basis Library structures having the same names.
  1976 
  1977 * 'refute' command added to search for (finite) countermodels.  Only works
  1978   for a fragment of HOL.  The installation of an external SAT solver is
  1979   highly recommended.  See "HOL/Refute.thy" for details.
  1980 
  1981 * 'quickcheck' command: Allows to find counterexamples by evaluating
  1982   formulae under an assignment of free variables to random values.
  1983   In contrast to 'refute', it can deal with inductive datatypes,
  1984   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  1985   for examples.
  1986 
  1987 
  1988 *** HOLCF ***
  1989 
  1990 * Streams now come with concatenation and are part of the HOLCF image
  1991 
  1992 
  1993 
  1994 New in Isabelle2003 (May 2003)
  1995 ------------------------------
  1996 
  1997 *** General ***
  1998 
  1999 * Provers/simplifier:
  2000 
  2001   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2002     Assumptions are now subject to complete mutual simplification,
  2003     not just from left to right. The simplifier now preserves
  2004     the order of assumptions.
  2005 
  2006     Potential INCOMPATIBILITY:
  2007 
  2008     -- simp sometimes diverges where the old version did
  2009        not, e.g. invoking simp on the goal
  2010 
  2011         [| P (f x); y = x; f x = f y |] ==> Q
  2012 
  2013        now gives rise to the infinite reduction sequence
  2014 
  2015         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2016 
  2017        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2018        kind of problem.
  2019 
  2020     -- Tactics combining classical reasoner and simplification (such as auto)
  2021        are also affected by this change, because many of them rely on
  2022        simp. They may sometimes diverge as well or yield a different numbers
  2023        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2024        in case of problems. Sometimes subsequent calls to the classical
  2025        reasoner will fail because a preceeding call to the simplifier too
  2026        eagerly simplified the goal, e.g. deleted redundant premises.
  2027 
  2028   - The simplifier trace now shows the names of the applied rewrite rules
  2029 
  2030   - You can limit the number of recursive invocations of the simplifier
  2031     during conditional rewriting (where the simplifie tries to solve the
  2032     conditions before applying the rewrite rule):
  2033     ML "simp_depth_limit := n"
  2034     where n is an integer. Thus you can force termination where previously
  2035     the simplifier would diverge.
  2036 
  2037   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2038 
  2039   - No longer aborts on failed congruence proof.  Instead, the
  2040     congruence is ignored.
  2041 
  2042 * Pure: New generic framework for extracting programs from constructive
  2043   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2044   as HOL/Extraction for some case studies.
  2045 
  2046 * Pure: The main goal of the proof state is no longer shown by default, only
  2047 the subgoals. This behaviour is controlled by a new flag.
  2048    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2049 (ML: Proof.show_main_goal).
  2050 
  2051 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2052 rules whose conclusion matches subgoal 1:
  2053       PG menu: Isabelle/Isar -> Show me -> matching rules
  2054 The rules are ordered by how closely they match the subgoal.
  2055 In particular, rules that solve a subgoal outright are displayed first
  2056 (or rather last, the way they are printed).
  2057 (ML: ProofGeneral.print_intros())
  2058 
  2059 * Pure: New flag trace_unify_fail causes unification to print
  2060 diagnostic information (PG: in trace buffer) when it fails. This is
  2061 useful for figuring out why single step proofs like rule, erule or
  2062 assumption failed.
  2063 
  2064 * Pure: Locale specifications now produce predicate definitions
  2065 according to the body of text (covering assumptions modulo local
  2066 definitions); predicate "loc_axioms" covers newly introduced text,
  2067 while "loc" is cumulative wrt. all included locale expressions; the
  2068 latter view is presented only on export into the global theory
  2069 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2070 on the old view without predicates;
  2071 
  2072 * Pure: predefined locales "var" and "struct" are useful for sharing
  2073 parameters (as in CASL, for example); just specify something like
  2074 ``var x + var y + struct M'' as import;
  2075 
  2076 * Pure: improved thms_containing: proper indexing of facts instead of
  2077 raw theorems; check validity of results wrt. current name space;
  2078 include local facts of proof configuration (also covers active
  2079 locales), cover fixed variables in index; may use "_" in term
  2080 specification; an optional limit for the number of printed facts may
  2081 be given (the default is 40);
  2082 
  2083 * Pure: disallow duplicate fact bindings within new-style theory files
  2084 (batch-mode only);
  2085 
  2086 * Provers: improved induct method: assumptions introduced by case
  2087 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2088 the goal statement); "foo" still refers to all facts collectively;
  2089 
  2090 * Provers: the function blast.overloaded has been removed: all constants
  2091 are regarded as potentially overloaded, which improves robustness in exchange
  2092 for slight decrease in efficiency;
  2093 
  2094 * Provers/linorder: New generic prover for transitivity reasoning over
  2095 linear orders.  Note: this prover is not efficient!
  2096 
  2097 * Isar: preview of problems to finish 'show' now produce an error
  2098 rather than just a warning (in interactive mode);
  2099 
  2100 
  2101 *** HOL ***
  2102 
  2103 * arith(_tac)
  2104 
  2105  - Produces a counter example if it cannot prove a goal.
  2106    Note that the counter example may be spurious if the goal is not a formula
  2107    of quantifier-free linear arithmetic.
  2108    In ProofGeneral the counter example appears in the trace buffer.
  2109 
  2110  - Knows about div k and mod k where k is a numeral of type nat or int.
  2111 
  2112  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2113    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2114    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2115 
  2116 * simp's arithmetic capabilities have been enhanced a bit: it now
  2117 takes ~= in premises into account (by performing a case split);
  2118 
  2119 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2120 are distributed over a sum of terms;
  2121 
  2122 * New tactic "trans_tac" and method "trans" instantiate
  2123 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2124 "<=", "<" and "=").
  2125 
  2126 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2127 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2128 
  2129 * 'typedef' command has new option "open" to suppress the set
  2130 definition;
  2131 
  2132 * functions Min and Max on finite sets have been introduced (theory
  2133 Finite_Set);
  2134 
  2135 * attribute [symmetric] now works for relations as well; it turns
  2136 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2137 
  2138 * induct over a !!-quantified statement (say !!x1..xn):
  2139   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2140 
  2141 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2142 %x. None. Warning: empty_def now refers to the previously hidden definition
  2143 of the empty set.
  2144 
  2145 * Algebra: formalization of classical algebra.  Intended as base for
  2146 any algebraic development in Isabelle.  Currently covers group theory
  2147 (up to Sylow's theorem) and ring theory (Universal Property of
  2148 Univariate Polynomials).  Contributions welcome;
  2149 
  2150 * GroupTheory: deleted, since its material has been moved to Algebra;
  2151 
  2152 * Complex: new directory of the complex numbers with numeric constants,
  2153 nonstandard complex numbers, and some complex analysis, standard and
  2154 nonstandard (Jacques Fleuriot);
  2155 
  2156 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2157 
  2158 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2159 Fleuriot);
  2160 
  2161 * Real/HahnBanach: updated and adapted to locales;
  2162 
  2163 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2164 Gray and Kramer);
  2165 
  2166 * UNITY: added the Meier-Sanders theory of progress sets;
  2167 
  2168 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2169 as abstract algorithms, instantiated to the JVM;
  2170 
  2171 * Bali: Java source language formalization. Type system, operational
  2172 semantics, axiomatic semantics. Supported language features:
  2173 classes, interfaces, objects,virtual methods, static methods,
  2174 static/instance fields, arrays, access modifiers, definite
  2175 assignment, exceptions.
  2176 
  2177 
  2178 *** ZF ***
  2179 
  2180 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2181 universe, etc.);
  2182 
  2183 * Main ZF: virtually all theories converted to new-style format;
  2184 
  2185 
  2186 *** ML ***
  2187 
  2188 * Pure: Tactic.prove provides sane interface for internal proofs;
  2189 omits the infamous "standard" operation, so this is more appropriate
  2190 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2191 
  2192 * Pure: improved error reporting of simprocs;
  2193 
  2194 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2195 up simprocs;
  2196 
  2197 
  2198 *** Document preparation ***
  2199 
  2200 * uses \par instead of \\ for line breaks in theory text. This may
  2201 shift some page breaks in large documents. To get the old behaviour
  2202 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2203 
  2204 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2205 other packages
  2206 
  2207 * \<euro> now needs package babel/greek instead of marvosym (which
  2208 broke \Rightarrow)
  2209 
  2210 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2211 textcomp package)
  2212 
  2213 
  2214 
  2215 New in Isabelle2002 (March 2002)
  2216 --------------------------------
  2217 
  2218 *** Document preparation ***
  2219 
  2220 * greatly simplified document preparation setup, including more
  2221 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2222 instructive isatool mkdir; users should basically be able to get
  2223 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2224 users may run a separate document processing stage manually like this:
  2225 "isatool usedir -D output HOL Test && isatool document Test/output";
  2226 
  2227 * theory dependency graph may now be incorporated into documents;
  2228 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2229 with \includegraphics of LaTeX;
  2230 
  2231 * proper spacing of consecutive markup elements, especially text
  2232 blocks after section headings;
  2233 
  2234 * support bold style (for single symbols only), input syntax is like
  2235 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2236 
  2237 * \<bullet> is now output as bold \cdot by default, which looks much
  2238 better in printed text;
  2239 
  2240 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2241 note that these symbols are currently unavailable in Proof General /
  2242 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2243 
  2244 * isatool latex no longer depends on changed TEXINPUTS, instead
  2245 isatool document copies the Isabelle style files to the target
  2246 location;
  2247 
  2248 
  2249 *** Isar ***
  2250 
  2251 * Pure/Provers: improved proof by cases and induction;
  2252   - 'case' command admits impromptu naming of parameters (such as
  2253     "case (Suc n)");
  2254   - 'induct' method divinates rule instantiation from the inductive
  2255     claim; no longer requires excessive ?P bindings for proper
  2256     instantiation of cases;
  2257   - 'induct' method properly enumerates all possibilities of set/type
  2258     rules; as a consequence facts may be also passed through *type*
  2259     rules without further ado;
  2260   - 'induct' method now derives symbolic cases from the *rulified*
  2261     rule (before it used to rulify cases stemming from the internal
  2262     atomized version); this means that the context of a non-atomic
  2263     statement becomes is included in the hypothesis, avoiding the
  2264     slightly cumbersome show "PROP ?case" form;
  2265   - 'induct' may now use elim-style induction rules without chaining
  2266     facts, using ``missing'' premises from the goal state; this allows
  2267     rules stemming from inductive sets to be applied in unstructured
  2268     scripts, while still benefitting from proper handling of non-atomic
  2269     statements; NB: major inductive premises need to be put first, all
  2270     the rest of the goal is passed through the induction;
  2271   - 'induct' proper support for mutual induction involving non-atomic
  2272     rule statements (uses the new concept of simultaneous goals, see
  2273     below);
  2274   - append all possible rule selections, but only use the first
  2275     success (no backtracking);
  2276   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2277   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2278   - added 'print_induct_rules' (covered by help item in recent Proof
  2279     General versions);
  2280   - moved induct/cases attributes to Pure, methods to Provers;
  2281   - generic method setup instantiated for FOL and HOL;
  2282 
  2283 * Pure: support multiple simultaneous goal statements, for example
  2284 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2285 meta-level mechanism, this acts as if several individual goals had
  2286 been stated separately; in particular common proof methods need to be
  2287 repeated in order to cover all claims; note that a single elimination
  2288 step is *not* sufficient to establish the two conjunctions, so this
  2289 fails:
  2290 
  2291   assume "A & B" then have A and B ..   (*".." fails*)
  2292 
  2293 better use "obtain" in situations as above; alternative refer to
  2294 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2295 
  2296 * Pure: proper integration with ``locales''; unlike the original
  2297 version by Florian Kammller, Isar locales package high-level proof
  2298 contexts rather than raw logical ones (e.g. we admit to include
  2299 attributes everywhere); operations on locales include merge and
  2300 rename; support for implicit arguments (``structures''); simultaneous
  2301 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2302 some examples;
  2303 
  2304 * Pure: the following commands have been ``localized'', supporting a
  2305 target locale specification "(in name)": 'lemma', 'theorem',
  2306 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2307 stored both within the locale and at the theory level (exported and
  2308 qualified by the locale name);
  2309 
  2310 * Pure: theory goals may now be specified in ``long'' form, with
  2311 ad-hoc contexts consisting of arbitrary locale elements. for example
  2312 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2313 definitions may be given, too); the result is a meta-level rule with
  2314 the context elements being discharged in the obvious way;
  2315 
  2316 * Pure: new proof command 'using' allows to augment currently used
  2317 facts after a goal statement ('using' is syntactically analogous to
  2318 'apply', but acts on the goal's facts only); this allows chained facts
  2319 to be separated into parts given before and after a claim, as in
  2320 ``from a and b have C using d and e <proof>'';
  2321 
  2322 * Pure: renamed "antecedent" case to "rule_context";
  2323 
  2324 * Pure: new 'judgment' command records explicit information about the
  2325 object-logic embedding (used by several tools internally); no longer
  2326 use hard-wired "Trueprop";
  2327 
  2328 * Pure: added 'corollary' command;
  2329 
  2330 * Pure: fixed 'token_translation' command;
  2331 
  2332 * Pure: removed obsolete 'exported' attribute;
  2333 
  2334 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2335 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2336 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2337 
  2338 * Pure: method 'atomize' presents local goal premises as object-level
  2339 statements (atomic meta-level propositions); setup controlled via
  2340 rewrite rules declarations of 'atomize' attribute; example
  2341 application: 'induct' method with proper rule statements in improper
  2342 proof *scripts*;
  2343 
  2344 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2345 now consider the syntactic context of assumptions, giving a better
  2346 chance to get type-inference of the arguments right (this is
  2347 especially important for locales);
  2348 
  2349 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2350 mode;
  2351 
  2352 * Pure/obtain: the formal conclusion "thesis", being marked as
  2353 ``internal'', may no longer be reference directly in the text;
  2354 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2355 situations;
  2356 
  2357 * Pure: generic 'sym' attribute which declares a rule both as pure
  2358 'elim?' and for the 'symmetric' operation;
  2359 
  2360 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2361 text; the fixed correlation with particular command syntax has been
  2362 discontinued;
  2363 
  2364 * Pure: new method 'rules' is particularly well-suited for proof
  2365 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2366 but often produces more compact proof terms with less detours;
  2367 
  2368 * Pure/Provers/classical: simplified integration with pure rule
  2369 attributes and methods; the classical "intro?/elim?/dest?"
  2370 declarations coincide with the pure ones; the "rule" method no longer
  2371 includes classically swapped intros; "intro" and "elim" methods no
  2372 longer pick rules from the context; also got rid of ML declarations
  2373 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2374 INCOMPATIBILITY;
  2375 
  2376 * Provers/classical: attribute 'swapped' produces classical inversions
  2377 of introduction rules;
  2378 
  2379 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2380 rules instead of full simplifier context; 'iff' attribute handles
  2381 conditional rules;
  2382 
  2383 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2384 
  2385 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2386 "(permissive)" option to recover old behavior;
  2387 
  2388 * HOL: 'inductive' no longer features separate (collective) attributes
  2389 for 'intros' (was found too confusing);
  2390 
  2391 * HOL: properly declared induction rules less_induct and
  2392 wf_induct_rule;
  2393 
  2394 
  2395 *** HOL ***
  2396 
  2397 * HOL: moved over to sane numeral syntax; the new policy is as
  2398 follows:
  2399 
  2400   - 0 and 1 are polymorphic constants, which are defined on any
  2401   numeric type (nat, int, real etc.);
  2402 
  2403   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2404   binary representation internally;
  2405 
  2406   - type nat has special constructor Suc, and generally prefers Suc 0
  2407   over 1::nat and Suc (Suc 0) over 2::nat;
  2408 
  2409 This change may cause significant problems of INCOMPATIBILITY; here
  2410 are some hints on converting existing sources:
  2411 
  2412   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2413   entities, so expressions involving "-" (unary or binary minus) need
  2414   to be spaced properly;
  2415 
  2416   - existing occurrences of "1" may need to be constraint "1::nat" or
  2417   even replaced by Suc 0; similar for old "2";
  2418 
  2419   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2420 
  2421   - remove all special provisions on numerals in proofs;
  2422 
  2423 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2424 representation (depends on bin_arith_simps in the default context);
  2425 
  2426 * HOL: symbolic syntax for x^2 (numeral 2);
  2427 
  2428 * HOL: the class of all HOL types is now called "type" rather than
  2429 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2430 in axclass/classes, instance/arities, and (usually rare) occurrences
  2431 in typings (of consts etc.); internally the class is called
  2432 "HOL.type", ML programs should refer to HOLogic.typeS;
  2433 
  2434 * HOL/record package improvements:
  2435   - new derived operations "fields" to build a partial record section,
  2436     "extend" to promote a fixed record to a record scheme, and
  2437     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2438     declared as simp by default;
  2439   - shared operations ("more", "fields", etc.) now need to be always
  2440     qualified) --- potential INCOMPATIBILITY;
  2441   - removed "make_scheme" operations (use "make" with "extend") --
  2442     INCOMPATIBILITY;
  2443   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2444   - provides cases/induct rules for use with corresponding Isar
  2445     methods (for concrete records, record schemes, concrete more
  2446     parts, and schematic more parts -- in that order);
  2447   - internal definitions directly based on a light-weight abstract
  2448     theory of product types over typedef rather than datatype;
  2449 
  2450 * HOL: generic code generator for generating executable ML code from
  2451 specifications; specific support for HOL constructs such as inductive
  2452 datatypes and sets, as well as recursive functions; can be invoked
  2453 via 'generate_code' theory section;
  2454 
  2455 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2456 
  2457 * HOL: consolidated and renamed several theories.  In particular:
  2458         Ord.thy has been absorbed into HOL.thy
  2459         String.thy has been absorbed into List.thy
  2460 
  2461 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2462 (beware of argument permutation!);
  2463 
  2464 * HOL: linorder_less_split superseded by linorder_cases;
  2465 
  2466 * HOL/List: "nodups" renamed to "distinct";
  2467 
  2468 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2469 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2470   - Ex_def has changed, now need to use some_eq_ex
  2471 
  2472 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2473 in this (rare) case use:
  2474 
  2475   delSWrapper "split_all_tac"
  2476   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2477 
  2478 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2479 MAY FAIL;
  2480 
  2481 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2482 Isabelle's type classes, ^ on functions and relations has too general
  2483 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2484 necessary to attach explicit type constraints;
  2485 
  2486 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2487 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2488 renamed accordingly (eg "compI" -> "rel_compI").
  2489 
  2490 * HOL: syntax translations now work properly with numerals and records
  2491 expressions;
  2492 
  2493 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2494 of "lam" -- INCOMPATIBILITY;
  2495 
  2496 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2497 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2498 renamed "Product_Type.unit";
  2499 
  2500 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2501 
  2502 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2503 the "cases" method);
  2504 
  2505 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2506 Florian Kammller);
  2507 
  2508 * HOL/IMP: updated and converted to new-style theory format; several
  2509 parts turned into readable document, with proper Isar proof texts and
  2510 some explanations (by Gerwin Klein);
  2511 
  2512 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2513 
  2514 * HOL-Hyperreal is now a logic image;
  2515 
  2516 
  2517 *** HOLCF ***
  2518 
  2519 * Isar: consts/constdefs supports mixfix syntax for continuous
  2520 operations;
  2521 
  2522 * Isar: domain package adapted to new-style theory format, e.g. see
  2523 HOLCF/ex/Dnat.thy;
  2524 
  2525 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2526 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2527 lift.induct_tac, always use UU instead of Undef;
  2528 
  2529 * HOLCF/IMP: updated and converted to new-style theory;
  2530 
  2531 
  2532 *** ZF ***
  2533 
  2534 * Isar: proper integration of logic-specific tools and packages,
  2535 including theory commands '(co)inductive', '(co)datatype',
  2536 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2537 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2538 
  2539 * theory Main no longer includes AC; for the Axiom of Choice, base
  2540 your theory on Main_ZFC;
  2541 
  2542 * the integer library now covers quotients and remainders, with many
  2543 laws relating division to addition, multiplication, etc.;
  2544 
  2545 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2546 typeless version of the formalism;
  2547 
  2548 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2549 format;
  2550 
  2551 * ZF/Induct: new directory for examples of inductive definitions,
  2552 including theory Multiset for multiset orderings; converted to
  2553 new-style theory format;
  2554 
  2555 * ZF: many new theorems about lists, ordinals, etc.;
  2556 
  2557 
  2558 *** General ***
  2559 
  2560 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2561 variable proof controls level of detail: 0 = no proofs (only oracle
  2562 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2563 also ref manual for further ML interfaces;
  2564 
  2565 * Pure/axclass: removed obsolete ML interface
  2566 goal_subclass/goal_arity;
  2567 
  2568 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2569 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2570 separate tokens, so expressions involving minus need to be spaced
  2571 properly;
  2572 
  2573 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2574 rather than "infixl" or "infixr";
  2575 
  2576 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2577 sort constraint specifications in type inference; e.g. "x::_::foo"
  2578 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2579 type variable);
  2580 
  2581 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2582 control output of nested => (types); the default behavior is
  2583 "type_brackets";
  2584 
  2585 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2586 tokens into AST constants;
  2587 
  2588 * Pure/syntax: prefer later declarations of translations and print
  2589 translation functions; potential INCOMPATIBILITY: need to reverse
  2590 multiple declarations for same syntax element constant;
  2591 
  2592 * Pure/show_hyps reset by default (in accordance to existing Isar
  2593 practice);
  2594 
  2595 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2596 addSafter;
  2597 
  2598 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2599 as well;
  2600 
  2601 * system: tested support for MacOS X; should be able to get Isabelle +
  2602 Proof General to work in a plain Terminal after installing Poly/ML
  2603 (e.g. from the Isabelle distribution area) and GNU bash alone
  2604 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2605 support requires further installations, e.g. from
  2606 http://fink.sourceforge.net/);
  2607 
  2608 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2609 
  2610 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2611 of 40 MB), cf. ML_OPTIONS;
  2612 
  2613 * system: Proof General keywords specification is now part of the
  2614 Isabelle distribution (see etc/isar-keywords.el);
  2615 
  2616 * system: support for persistent Proof General sessions (refrain from
  2617 outdating all loaded theories on startup); user may create writable
  2618 logic images like this: ``isabelle -q HOL Test'';
  2619 
  2620 * system: smart selection of Isabelle process versus Isabelle
  2621 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2622 run both "isabelle" and "Isabelle" even if file names are badly
  2623 damaged (executable inspects the case of the first letter of its own
  2624 name); added separate "isabelle-process" and "isabelle-interface";
  2625 
  2626 * system: refrain from any attempt at filtering input streams; no
  2627 longer support ``8bit'' encoding of old isabelle font, instead proper
  2628 iso-latin characters may now be used; the related isatools
  2629 "symbolinput" and "nonascii" have disappeared as well;
  2630 
  2631 * system: removed old "xterm" interface (the print modes "xterm" and
  2632 "xterm_color" are still available for direct use in a suitable
  2633 terminal);
  2634 
  2635 
  2636 
  2637 New in Isabelle99-2 (February 2001)
  2638 -----------------------------------
  2639 
  2640 *** Overview of INCOMPATIBILITIES ***
  2641 
  2642 * HOL: please note that theories in the Library and elsewhere often use the
  2643 new-style (Isar) format; to refer to their theorems in an ML script you must
  2644 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2645 
  2646 * HOL: inductive package no longer splits induction rule aggressively,
  2647 but only as far as specified by the introductions given; the old
  2648 format may be recovered via ML function complete_split_rule or attribute
  2649 'split_rule (complete)';
  2650 
  2651 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2652 gfp_Tarski to gfp_unfold;
  2653 
  2654 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2655 
  2656 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2657 relation); infix "^^" has been renamed "``"; infix "``" has been
  2658 renamed "`"; "univalent" has been renamed "single_valued";
  2659 
  2660 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2661 operation;
  2662 
  2663 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2664 
  2665 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2666 
  2667 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2668 consequence, it is no longer monotonic wrt. the local goal context
  2669 (which is now passed through the inductive cases);
  2670 
  2671 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2672 \<gg> to \<ggreater>;
  2673 
  2674 
  2675 *** Document preparation ***
  2676 
  2677 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2678 available: are "it" for near math-mode best-style output, "sl" for
  2679 slanted text style, and "tt" for plain type-writer; if no
  2680 \isabellestyle command is given, output is according to slanted
  2681 type-writer);
  2682 
  2683 * support sub/super scripts (for single symbols only), input syntax is
  2684 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2685 
  2686 * some more standard symbols; see Appendix A of the system manual for
  2687 the complete list of symbols defined in isabellesym.sty;
  2688 
  2689 * improved isabelle style files; more abstract symbol implementation
  2690 (should now use \isamath{...} and \isatext{...} in custom symbol
  2691 definitions);
  2692 
  2693 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2694 state; Note that presentation of goal states does not conform to
  2695 actual human-readable proof documents.  Please do not include goal
  2696 states into document output unless you really know what you are doing!
  2697 
  2698 * proper indentation of antiquoted output with proportional LaTeX
  2699 fonts;
  2700 
  2701 * no_document ML operator temporarily disables LaTeX document
  2702 generation;
  2703 
  2704 * isatool unsymbolize tunes sources for plain ASCII communication;
  2705 
  2706 
  2707 *** Isar ***
  2708 
  2709 * Pure: Isar now suffers initial goal statements to contain unbound
  2710 schematic variables (this does not conform to actual readable proof
  2711 documents, due to unpredictable outcome and non-compositional proof
  2712 checking); users who know what they are doing may use schematic goals
  2713 for Prolog-style synthesis of proven results;
  2714 
  2715 * Pure: assumption method (an implicit finishing) now handles actual
  2716 rules as well;
  2717 
  2718 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  2719 initial goal, declare "that" only as Pure intro (only for single
  2720 steps); the "that" rule assumption may now be involved in implicit
  2721 finishing, thus ".." becomes a feasible for trivial obtains;
  2722 
  2723 * Pure: default proof step now includes 'intro_classes'; thus trivial
  2724 instance proofs may be performed by "..";
  2725 
  2726 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  2727 statements as well;
  2728 
  2729 * Pure: more robust selection of calculational rules;
  2730 
  2731 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  2732 rule (as well as the assumption rule);
  2733 
  2734 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  2735 lemmas, using the graph browser tool;
  2736 
  2737 * Pure: predict failure of "show" in interactive mode;
  2738 
  2739 * Pure: 'thms_containing' now takes actual terms as arguments;
  2740 
  2741 * HOL: improved method 'induct' --- now handles non-atomic goals
  2742 (potential INCOMPATIBILITY); tuned error handling;
  2743 
  2744 * HOL: cases and induct rules now provide explicit hints about the
  2745 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  2746 any remaining facts are inserted into the goal verbatim;
  2747 
  2748 * HOL: local contexts (aka cases) may now contain term bindings as
  2749 well; the 'cases' and 'induct' methods new provide a ?case binding for
  2750 the result to be shown in each case;
  2751 
  2752 * HOL: added 'recdef_tc' command;
  2753 
  2754 * isatool convert assists in eliminating legacy ML scripts;
  2755 
  2756 
  2757 *** HOL ***
  2758 
  2759 * HOL/Library: a collection of generic theories to be used together
  2760 with main HOL; the theory loader path already includes this directory
  2761 by default; the following existing theories have been moved here:
  2762 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  2763 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  2764 
  2765 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  2766 modelling and verification task performed in Isabelle/HOL +
  2767 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  2768 
  2769 * HOL/Algebra: special summation operator SUM no longer exists, it has
  2770 been replaced by setsum; infix 'assoc' now has priority 50 (like
  2771 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  2772 'domain', this makes the theory consistent with mathematical
  2773 literature;
  2774 
  2775 * HOL basics: added overloaded operations "inverse" and "divide"
  2776 (infix "/"), syntax for generic "abs" operation, generic summation
  2777 operator \<Sum>;
  2778 
  2779 * HOL/typedef: simplified package, provide more useful rules (see also
  2780 HOL/subset.thy);
  2781 
  2782 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  2783 now expressed as a proper nested rule (old-style tactic scripts may
  2784 require atomize_strip_tac to cope with non-atomic premises);
  2785 
  2786 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  2787 to "split_conv" (old name still available for compatibility);
  2788 
  2789 * HOL: improved concrete syntax for strings (e.g. allows translation
  2790 rules with string literals);
  2791 
  2792 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  2793  and Fleuriot's mechanization of analysis, including the transcendental
  2794  functions for the reals;
  2795 
  2796 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  2797 
  2798 
  2799 *** CTT ***
  2800 
  2801 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2802 "lam" is displayed as TWO lambda-symbols
  2803 
  2804 * CTT: theory Main now available, containing everything (that is, Bool
  2805 and Arith);
  2806 
  2807 
  2808 *** General ***
  2809 
  2810 * Pure: the Simplifier has been implemented properly as a derived rule
  2811 outside of the actual kernel (at last!); the overall performance
  2812 penalty in practical applications is about 50%, while reliability of
  2813 the Isabelle inference kernel has been greatly improved;
  2814 
  2815 * print modes "brackets" and "no_brackets" control output of nested =>
  2816 (types) and ==> (props); the default behaviour is "brackets";
  2817 
  2818 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2819 as assumptions as well;
  2820 
  2821 * system: support Poly/ML 4.0;
  2822 
  2823 * system: isatool install handles KDE version 1 or 2;
  2824 
  2825 
  2826 
  2827 New in Isabelle99-1 (October 2000)
  2828 ----------------------------------
  2829 
  2830 *** Overview of INCOMPATIBILITIES ***
  2831 
  2832 * HOL: simplification of natural numbers is much changed; to partly
  2833 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  2834 issue the following ML commands:
  2835 
  2836   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  2837   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  2838 
  2839 * HOL: simplification no longer dives into case-expressions; this is
  2840 controlled by "t.weak_case_cong" for each datatype t;
  2841 
  2842 * HOL: nat_less_induct renamed to less_induct;
  2843 
  2844 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  2845 fixsome to patch .thy and .ML sources automatically;
  2846 
  2847   select_equality  -> some_equality
  2848   select_eq_Ex     -> some_eq_ex
  2849   selectI2EX       -> someI2_ex
  2850   selectI2         -> someI2
  2851   selectI          -> someI
  2852   select1_equality -> some1_equality
  2853   Eps_sym_eq       -> some_sym_eq_trivial
  2854   Eps_eq           -> some_eq_trivial
  2855 
  2856 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  2857 
  2858 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  2859 instead);
  2860 
  2861 * HOL: the recursion equations generated by 'recdef' are now called
  2862 f.simps instead of f.rules;
  2863 
  2864 * HOL: qed_spec_mp now also handles bounded ALL as well;
  2865 
  2866 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  2867 sometimes be needed;
  2868 
  2869 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  2870 
  2871 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  2872 
  2873 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  2874 product is now "<*>" instead of "Times"; the lexicographic product is
  2875 now "<*lex*>" instead of "**";
  2876 
  2877 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  2878 of main HOL, but was unused); better use HOL's datatype package;
  2879 
  2880 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  2881 the old syntax may be recovered as follows:
  2882 
  2883   syntax (symbols)
  2884     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  2885       (infixl "\\<oplus>" 100)
  2886 
  2887 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2888 
  2889 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  2890 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  2891 internally;
  2892 
  2893 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  2894 changed from A/r to A//r;
  2895 
  2896 * ZF: new treatment of arithmetic (nat & int) may break some old
  2897 proofs;
  2898 
  2899 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  2900 rulify -> rule_format, elimify -> elim_format, ...);
  2901 
  2902 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2903 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  2904 should have to change intro!! to intro? only); replaced "delrule" by
  2905 "rule del";
  2906 
  2907 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  2908 
  2909 * Provers: strengthened force_tac by using new first_best_tac;
  2910 
  2911 * LaTeX document preparation: several changes of isabelle.sty (see
  2912 lib/texinputs);
  2913 
  2914 
  2915 *** Document preparation ***
  2916 
  2917 * formal comments (text blocks etc.) in new-style theories may now
  2918 contain antiquotations of thm/prop/term/typ/text to be presented
  2919 according to latex print mode; concrete syntax is like this:
  2920 @{term[show_types] "f(x) = a + x"};
  2921 
  2922 * isatool mkdir provides easy setup of Isabelle session directories,
  2923 including proper document sources;
  2924 
  2925 * generated LaTeX sources are now deleted after successful run
  2926 (isatool document -c); may retain a copy somewhere else via -D option
  2927 of isatool usedir;
  2928 
  2929 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  2930 style files, achieving self-contained LaTeX sources and simplifying
  2931 LaTeX debugging;
  2932 
  2933 * old-style theories now produce (crude) LaTeX output as well;
  2934 
  2935 * browser info session directories are now self-contained (may be put
  2936 on WWW server seperately); improved graphs of nested sessions; removed
  2937 graph for 'all sessions';
  2938 
  2939 * several improvements in isabelle style files; \isabellestyle{it}
  2940 produces fake math mode output; \isamarkupheader is now \section by
  2941 default; see lib/texinputs/isabelle.sty etc.;
  2942 
  2943 
  2944 *** Isar ***
  2945 
  2946 * Isar/Pure: local results and corresponding term bindings are now
  2947 subject to Hindley-Milner polymorphism (similar to ML); this
  2948 accommodates incremental type-inference very nicely;
  2949 
  2950 * Isar/Pure: new derived language element 'obtain' supports
  2951 generalized existence reasoning;
  2952 
  2953 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  2954 support accumulation of results, without applying any rules yet;
  2955 useful to collect intermediate results without explicit name
  2956 references, and for use with transitivity rules with more than 2
  2957 premises;
  2958 
  2959 * Isar/Pure: scalable support for case-analysis type proofs: new
  2960 'case' language element refers to local contexts symbolically, as
  2961 produced by certain proof methods; internally, case names are attached
  2962 to theorems as "tags";
  2963 
  2964 * Isar/Pure: theory command 'hide' removes declarations from
  2965 class/type/const name spaces;
  2966 
  2967 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  2968 indicate potential overloading;
  2969 
  2970 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  2971 
  2972 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  2973 "{a,b,c}" instead of {a,b,c};
  2974 
  2975 * Isar/Pure now provides its own version of intro/elim/dest
  2976 attributes; useful for building new logics, but beware of confusion
  2977 with the version in Provers/classical;
  2978 
  2979 * Isar/Pure: the local context of (non-atomic) goals is provided via
  2980 case name 'antecedent';
  2981 
  2982 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  2983 to the current context is now done automatically);
  2984 
  2985 * Isar/Pure: theory command 'method_setup' provides a simple interface
  2986 for definining proof methods in ML;
  2987 
  2988 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2989 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  2990 most cases, one should have to change intro!! to intro? only);
  2991 replaced "delrule" by "rule del";
  2992 
  2993 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  2994 'symmetric' attribute (the latter supercedes [RS sym]);
  2995 
  2996 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  2997 method modifier); 'simp' method: 'only:' modifier removes loopers as
  2998 well (including splits);
  2999 
  3000 * Isar/Provers: Simplifier and Classical methods now support all kind
  3001 of modifiers used in the past, including 'cong', 'iff', etc.
  3002 
  3003 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3004 of Simplifier and Classical reasoner);
  3005 
  3006 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3007 now support named cases; major packages (inductive, datatype, primrec,
  3008 recdef) support case names and properly name parameters;
  3009 
  3010 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3011 monotonicity conditions are extracted to be proven at end of
  3012 calculations;
  3013 
  3014 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3015 method anyway;
  3016 
  3017 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3018 split_if split_if_asm; datatype package provides theorems foo.splits =
  3019 foo.split foo.split_asm for each datatype;
  3020 
  3021 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3022 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3023 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3024 use "(cases (simplified))" method in proper proof texts);
  3025 
  3026 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3027 
  3028 * Isar: names of theorems etc. may be natural numbers as well;
  3029 
  3030 * Isar: 'pr' command: optional arguments for goals_limit and
  3031 ProofContext.prems_limit; no longer prints theory contexts, but only
  3032 proof states;
  3033 
  3034 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3035 additional print modes to be specified; e.g. "pr(latex)" will print
  3036 proof state according to the Isabelle LaTeX style;
  3037 
  3038 * Isar: improved support for emulating tactic scripts, including proof
  3039 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3040 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3041 (for HOL datatypes);
  3042 
  3043 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3044 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3045 'proof method scripts' have to be in depth-first order;
  3046 
  3047 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3048 
  3049 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3050 should instead use individual commands for printing items
  3051 (print_commands, print_methods etc.);
  3052 
  3053 * Isar: added 'nothing' --- the empty list of theorems;
  3054 
  3055 
  3056 *** HOL ***
  3057 
  3058 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3059 corresponding virtual machine and a specification of its bytecode
  3060 verifier and a lightweight bytecode verifier, including proofs of
  3061 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3062 Cornelia Pusch (see also the homepage of project Bali at
  3063 http://isabelle.in.tum.de/Bali/);
  3064 
  3065 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3066 Clemens Ballarin;
  3067 
  3068 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3069 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3070 Rasmussen;
  3071 
  3072 * HOL/Lattice: fundamental concepts of lattice theory and order
  3073 structures, including duals, properties of bounds versus algebraic
  3074 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3075 Theorem for complete lattices etc.; may also serve as a demonstration
  3076 for abstract algebraic reasoning using axiomatic type classes, and
  3077 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3078 
  3079 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3080 von Oheimb;
  3081 
  3082 * HOL/IMPP: extension of IMP with local variables and mutually
  3083 recursive procedures, by David von Oheimb;
  3084 
  3085 * HOL/Lambda: converted into new-style theory and document;
  3086 
  3087 * HOL/ex/Multiquote: example of multiple nested quotations and
  3088 anti-quotations -- basically a generalized version of de-Bruijn
  3089 representation; very useful in avoiding lifting of operations;
  3090 
  3091 * HOL/record: added general record equality rule to simpset; fixed
  3092 select-update simplification procedure to handle extended records as
  3093 well; admit "r" as field name;
  3094 
  3095 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3096 other numeric types and also as the identity of groups, rings, etc.;
  3097 
  3098 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3099 Types nat and int belong to this axclass;
  3100 
  3101 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3102    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3103    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3104   two terms #m*u and #n*u are replaced by #(m+n)*u
  3105     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3106   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3107     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3108 
  3109 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3110 powerful prover for predicate logic but knows nothing of clasets; see
  3111 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3112 
  3113 * HOL: new version of "case_tac" subsumes both boolean case split and
  3114 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3115 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3116 
  3117 * HOL: simplification no longer dives into case-expressions: only the
  3118 selector expression is simplified, but not the remaining arms; to
  3119 enable full simplification of case-expressions for datatype t, you may
  3120 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3121 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3122 
  3123 * HOL/recdef: the recursion equations generated by 'recdef' for
  3124 function 'f' are now called f.simps instead of f.rules; if all
  3125 termination conditions are proved automatically, these simplification
  3126 rules are added to the simpset, as in primrec; rules may be named
  3127 individually as well, resulting in a separate list of theorems for
  3128 each equation;
  3129 
  3130 * HOL/While is a new theory that provides a while-combinator. It
  3131 permits the definition of tail-recursive functions without the
  3132 provision of a termination measure. The latter is necessary once the
  3133 invariant proof rule for while is applied.
  3134 
  3135 * HOL: new (overloaded) notation for the set of elements below/above
  3136 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3137 
  3138 * HOL: theorems impI, allI, ballI bound as "strip";
  3139 
  3140 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3141 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3142 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3143 
  3144 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3145 
  3146 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3147 main HOL, but was unused);
  3148 
  3149 * HOL: fewer consts declared as global (e.g. have to refer to
  3150 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3151 
  3152 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3153 in case of overlap with user translations (e.g. judgements over
  3154 tuples); (note that the underlying logical represenation is still
  3155 bogus);
  3156 
  3157 
  3158 *** ZF ***
  3159 
  3160 * ZF: simplification automatically cancels common terms in arithmetic
  3161 expressions over nat and int;
  3162 
  3163 * ZF: new treatment of nat to minimize type-checking: all operators
  3164 coerce their operands to a natural number using the function natify,
  3165 making the algebraic laws unconditional;
  3166 
  3167 * ZF: as above, for int: operators coerce their operands to an integer
  3168 using the function intify;
  3169 
  3170 * ZF: the integer library now contains many of the usual laws for the
  3171 orderings, including $<=, and monotonicity laws for $+ and $*;
  3172 
  3173 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3174 simplification;
  3175 
  3176 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3177 to the simplifier and classical reasoner simultaneously;
  3178 
  3179 
  3180 *** General ***
  3181 
  3182 * Provers: blast_tac now handles actual object-logic rules as
  3183 assumptions; note that auto_tac uses blast_tac internally as well;
  3184 
  3185 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3186 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3187 
  3188 * Provers: delrules now handles destruct rules as well (no longer need
  3189 explicit make_elim);
  3190 
  3191 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3192   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3193 use instead the strong form,
  3194   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3195 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3196 from destruct-rules;
  3197 
  3198 * Provers: Simplifier.easy_setup provides a fast path to basic
  3199 Simplifier setup for new object-logics;
  3200 
  3201 * Pure: AST translation rules no longer require constant head on LHS;
  3202 
  3203 * Pure: improved name spaces: ambiguous output is qualified; support
  3204 for hiding of names;
  3205 
  3206 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3207 XSYMBOL_HOME; no longer need to do manual configuration in most
  3208 situations;
  3209 
  3210 * system: compression of ML heaps images may now be controlled via -c
  3211 option of isabelle and isatool usedir (currently only observed by
  3212 Poly/ML);
  3213 
  3214 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3215 useful for remote X11);
  3216 
  3217 * system: provide TAGS file for Isabelle sources;
  3218 
  3219 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3220 order;
  3221 
  3222 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3223 timing flag supersedes proof_timing and Toplevel.trace;
  3224 
  3225 * ML: new combinators |>> and |>>> for incremental transformations
  3226 with secondary results (e.g. certain theory extensions):
  3227 
  3228 * ML: PureThy.add_defs gets additional argument to indicate potential
  3229 overloading (usually false);
  3230 
  3231 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3232 results;
  3233 
  3234 
  3235 
  3236 New in Isabelle99 (October 1999)
  3237 --------------------------------
  3238 
  3239 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3240 
  3241 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3242 are no longer simplified.  (This allows the simplifier to unfold recursive
  3243 functional programs.)  To restore the old behaviour, declare
  3244 
  3245     Delcongs [if_weak_cong];
  3246 
  3247 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3248 complement;
  3249 
  3250 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3251 
  3252 * HOL/datatype: mutual_induct_tac no longer exists --
  3253   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3254 
  3255 * HOL/typedef: fixed type inference for representing set; type
  3256 arguments now have to occur explicitly on the rhs as type constraints;
  3257 
  3258 * ZF: The con_defs part of an inductive definition may no longer refer
  3259 to constants declared in the same theory;
  3260 
  3261 * HOL, ZF: the function mk_cases, generated by the inductive
  3262 definition package, has lost an argument.  To simplify its result, it
  3263 uses the default simpset instead of a supplied list of theorems.
  3264 
  3265 * HOL/List: the constructors of type list are now Nil and Cons;
  3266 
  3267 * Simplifier: the type of the infix ML functions
  3268         setSSolver addSSolver setSolver addSolver
  3269 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3270 for packaging solvers. A solver is created via
  3271         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3272 where the string argument is only a comment.
  3273 
  3274 
  3275 *** Proof tools ***
  3276 
  3277 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3278 decision procedure for linear arithmetic. Currently it is used for
  3279 types `nat', `int', and `real' in HOL (see below); it can, should and
  3280 will be instantiated for other types and logics as well.
  3281 
  3282 * The simplifier now accepts rewrite rules with flexible heads, eg
  3283      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3284   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3285   matching.
  3286 
  3287 
  3288 *** General ***
  3289 
  3290 * New Isabelle/Isar subsystem provides an alternative to traditional
  3291 tactical theorem proving; together with the ProofGeneral/isar user
  3292 interface it offers an interactive environment for developing human
  3293 readable proof documents (Isar == Intelligible semi-automated
  3294 reasoning); for further information see isatool doc isar-ref,
  3295 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3296 
  3297 * improved and simplified presentation of theories: better HTML markup
  3298 (including colors), graph views in several sizes; isatool usedir now
  3299 provides a proper interface for user theories (via -P option); actual
  3300 document preparation based on (PDF)LaTeX is available as well (for
  3301 new-style theories only); see isatool doc system for more information;
  3302 
  3303 * native support for Proof General, both for classic Isabelle and
  3304 Isabelle/Isar;
  3305 
  3306 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3307 using the graph browser tool;
  3308 
  3309 * Isabelle manuals now also available as PDF;
  3310 
  3311 * theory loader rewritten from scratch (may not be fully
  3312 bug-compatible); old loadpath variable has been replaced by show_path,
  3313 add_path, del_path, reset_path functions; new operations such as
  3314 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3315 isatool doc ref);
  3316 
  3317 * improved isatool install: option -k creates KDE application icon,
  3318 option -p DIR installs standalone binaries;
  3319 
  3320 * added ML_PLATFORM setting (useful for cross-platform installations);
  3321 more robust handling of platform specific ML images for SML/NJ;
  3322 
  3323 * the settings environment is now statically scoped, i.e. it is never
  3324 created again in sub-processes invoked from isabelle, isatool, or
  3325 Isabelle;
  3326 
  3327 * path element specification '~~' refers to '$ISABELLE_HOME';
  3328 
  3329 * in locales, the "assumes" and "defines" parts may be omitted if
  3330 empty;
  3331 
  3332 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3333 long arrows);
  3334 
  3335 * new print_mode "HTML";
  3336 
  3337 * new flag show_tags controls display of tags of theorems (which are
  3338 basically just comments that may be attached by some tools);
  3339 
  3340 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3341 mode and goal output format:
  3342 
  3343 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3344 244c244
  3345 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3346 ---
  3347 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3348 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3349 181c181
  3350 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3351 ---
  3352 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3353 
  3354 * function bind_thms stores lists of theorems (cf. bind_thm);
  3355 
  3356 * new shorthand tactics ftac, eatac, datac, fatac;
  3357 
  3358 * qed (and friends) now accept "" as result name; in that case the
  3359 theorem is not stored, but proper checks and presentation of the
  3360 result still apply;
  3361 
  3362 * theorem database now also indexes constants "Trueprop", "all",
  3363 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3364 
  3365 
  3366 *** HOL ***
  3367 
  3368 ** HOL arithmetic **
  3369 
  3370 * There are now decision procedures for linear arithmetic over nat and
  3371 int:
  3372 
  3373 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3374 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3375 are treated as atomic; subformulae not involving type `nat' or `int'
  3376 are ignored; quantified subformulae are ignored unless they are
  3377 positive universal or negative existential. The tactic has to be
  3378 invoked by hand and can be a little bit slow. In particular, the
  3379 running time is exponential in the number of occurrences of `min' and
  3380 `max', and `-' on `nat'.
  3381 
  3382 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3383 (negated) (in)equalities among the premises and the conclusion into
  3384 account (i.e. no compound formulae) and does not know about `min' and
  3385 `max', and `-' on `nat'. It is fast and is used automatically by the
  3386 simplifier.
  3387 
  3388 NB: At the moment, these decision procedures do not cope with mixed
  3389 nat/int formulae where the two parts interact, such as `m < n ==>
  3390 int(m) < int(n)'.
  3391 
  3392 * HOL/Numeral provides a generic theory of numerals (encoded
  3393 efficiently as bit strings); setup for types nat/int/real is in place;
  3394 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3395 int, existing theories and proof scripts may require a few additional
  3396 type constraints;
  3397 
  3398 * integer division and remainder can now be performed on constant
  3399 arguments;
  3400 
  3401 * many properties of integer multiplication, division and remainder
  3402 are now available;
  3403 
  3404 * An interface to the Stanford Validity Checker (SVC) is available through the
  3405 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3406 are proved automatically.  SVC must be installed separately, and its results
  3407 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3408 invocation of the underlying oracle).  For SVC see
  3409   http://verify.stanford.edu/SVC
  3410 
  3411 * IsaMakefile: the HOL-Real target now builds an actual image;
  3412 
  3413 
  3414 ** HOL misc **
  3415 
  3416 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3417 (in Isabelle/Isar) -- by Gertrud Bauer;
  3418 
  3419 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3420 analysis for assembly languages with subtypes;
  3421 
  3422 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3423 -- avoids syntactic ambiguities and treats state, transition, and
  3424 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3425 changed syntax and (many) tactics;
  3426 
  3427 * HOL/inductive: Now also handles more general introduction rules such
  3428   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3429   theorems are now maintained within the theory (maintained via the
  3430   "mono" attribute);
  3431 
  3432 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3433   (using function types) such as
  3434 
  3435   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3436 
  3437 * HOL/record: record_simproc (part of the default simpset) takes care
  3438 of selectors applied to updated records; record_split_tac is no longer
  3439 part of the default claset; update_defs may now be removed from the
  3440 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3441 
  3442   claset_ref () := claset() addSWrapper record_split_wrapper;
  3443   Delsimprocs [record_simproc]
  3444 
  3445 * HOL/typedef: fixed type inference for representing set; type
  3446 arguments now have to occur explicitly on the rhs as type constraints;
  3447 
  3448 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3449 names rather than an ML expression;
  3450 
  3451 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3452 supplied later.  Program schemes can be defined, such as
  3453     "While B C s = (if B s then While B C (C s) else s)"
  3454 where the well-founded relation can be chosen after B and C have been given.
  3455 
  3456 * HOL/List: the constructors of type list are now Nil and Cons;
  3457 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3458 course, ML tools referring to List.list.op # etc. have to be adapted;
  3459 
  3460 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3461 disabled by default; run isabelle with option -m HOL to get back to
  3462 the original Gordon/HOL-style output;
  3463 
  3464 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3465 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3466 
  3467 * HOL basic syntax simplified (more orthogonal): all variants of
  3468 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3469 Eps operator is provided as well: "SOME x. P[x]";
  3470 
  3471 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3472 
  3473 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3474 thus available for user theories;
  3475 
  3476 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3477 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3478 time;
  3479 
  3480 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3481 several times and then mp;
  3482 
  3483 
  3484 *** LK ***
  3485 
  3486 * the notation <<...>> is now available as a notation for sequences of
  3487 formulas;
  3488 
  3489 * the simplifier is now installed
  3490 
  3491 * the axiom system has been generalized (thanks to Soren Heilmann)
  3492 
  3493 * the classical reasoner now has a default rule database
  3494 
  3495 
  3496 *** ZF ***
  3497 
  3498 * new primrec section allows primitive recursive functions to be given
  3499 directly (as in HOL) over datatypes and the natural numbers;
  3500 
  3501 * new tactics induct_tac and exhaust_tac for induction (or case
  3502 analysis) over datatypes and the natural numbers;
  3503 
  3504 * the datatype declaration of type T now defines the recursor T_rec;
  3505 
  3506 * simplification automatically does freeness reasoning for datatype
  3507 constructors;
  3508 
  3509 * automatic type-inference, with AddTCs command to insert new
  3510 type-checking rules;
  3511 
  3512 * datatype introduction rules are now added as Safe Introduction rules
  3513 to the claset;
  3514 
  3515 * the syntax "if P then x else y" is now available in addition to
  3516 if(P,x,y);
  3517 
  3518 
  3519 *** Internal programming interfaces ***
  3520 
  3521 * tuned simplifier trace output; new flag debug_simp;
  3522 
  3523 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3524 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3525 
  3526 * AxClass.axclass_tac lost the theory argument;
  3527 
  3528 * tuned current_goals_markers semantics: begin / end goal avoids
  3529 printing empty lines;
  3530 
  3531 * removed prs and prs_fn hook, which was broken because it did not
  3532 include \n in its semantics, forcing writeln to add one
  3533 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3534 string -> unit if you really want to output text without newline;
  3535 
  3536 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3537 plain output, interface builders may have to enable 'isabelle_font'
  3538 mode to get Isabelle font glyphs as before;
  3539 
  3540 * refined token_translation interface; INCOMPATIBILITY: output length
  3541 now of type real instead of int;
  3542 
  3543 * theory loader actions may be traced via new ThyInfo.add_hook
  3544 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3545 your own database of information attached to *whole* theories -- as
  3546 opposed to intra-theory data slots offered via TheoryDataFun;
  3547 
  3548 * proper handling of dangling sort hypotheses (at last!);
  3549 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3550 extra sort hypotheses that can be witnessed from the type signature;
  3551 the force_strip_shyps flag is gone, any remaining shyps are simply
  3552 left in the theorem (with a warning issued by strip_shyps_warning);
  3553 
  3554 
  3555 
  3556 New in Isabelle98-1 (October 1998)
  3557 ----------------------------------
  3558 
  3559 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3560 
  3561 * several changes of automated proof tools;
  3562 
  3563 * HOL: major changes to the inductive and datatype packages, including
  3564 some minor incompatibilities of theory syntax;
  3565 
  3566 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3567 called `inj_on';
  3568 
  3569 * HOL: removed duplicate thms in Arith:
  3570   less_imp_add_less  should be replaced by  trans_less_add1
  3571   le_imp_add_le      should be replaced by  trans_le_add1
  3572 
  3573 * HOL: unary minus is now overloaded (new type constraints may be
  3574 required);
  3575 
  3576 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3577 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3578 now taken as an integer constant.
  3579 
  3580 * Pure: ML function 'theory_of' renamed to 'theory';
  3581 
  3582 
  3583 *** Proof tools ***
  3584 
  3585 * Simplifier:
  3586   1. Asm_full_simp_tac is now more aggressive.
  3587      1. It will sometimes reorient premises if that increases their power to
  3588         simplify.
  3589      2. It does no longer proceed strictly from left to right but may also
  3590         rotate premises to achieve further simplification.
  3591      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3592      old Asm_full_simp_tac in that it does not rotate premises.
  3593   2. The simplifier now knows a little bit about nat-arithmetic.
  3594 
  3595 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3596 allows for selected deletion of wrappers, by introduction of names for
  3597 wrapper functionals.  This implies that addbefore, addSbefore,
  3598 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3599 and that adding two tactics with the same name overwrites the first
  3600 one (emitting a warning).
  3601   type wrapper = (int -> tactic) -> (int -> tactic)
  3602   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3603   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3604   delWrapper, delSWrapper: claset *  string            -> claset
  3605   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3606 
  3607 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3608 semantics; addbefore now affects only the unsafe part of step_tac
  3609 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3610 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3611 by Force_tac;
  3612 
  3613 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3614 compWrapper; added safe wrapper (and access functions for it);
  3615 
  3616 * HOL/split_all_tac is now much faster and fails if there is nothing
  3617 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3618 and the names of the automatically generated variables have changed.
  3619 split_all_tac has moved within claset() from unsafe wrappers to safe
  3620 wrappers, which means that !!-bound variables are split much more
  3621 aggressively, and safe_tac and clarify_tac now split such variables.
  3622 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3623 Note: the same holds for record_split_tac, which does the job of
  3624 split_all_tac for record fields.
  3625 
  3626 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3627 permanently to the default simpset using Addsplits just like
  3628 Addsimps. They can be removed via Delsplits just like
  3629 Delsimps. Lower-case versions are also available.
  3630 
  3631 * HOL/Simplifier: The rule split_if is now part of the default
  3632 simpset. This means that the simplifier will eliminate all occurrences
  3633 of if-then-else in the conclusion of a goal. To prevent this, you can
  3634 either remove split_if completely from the default simpset by
  3635 `Delsplits [split_if]' or remove it in a specific call of the
  3636 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3637 other case splitting rules to/from the default simpset: every datatype
  3638 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3639 t is the name of the datatype).
  3640 
  3641 * Classical reasoner / Simplifier combination: new force_tac (and
  3642 derivatives Force_tac, force) combines rewriting and classical
  3643 reasoning (and whatever other tools) similarly to auto_tac, but is
  3644 aimed to solve the given subgoal completely.
  3645 
  3646 
  3647 *** General ***
  3648 
  3649 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3650 and `goalw': the theory is no longer needed as an explicit argument -
  3651 the current theory context is used; assumptions are no longer returned
  3652 at the ML-level unless one of them starts with ==> or !!; it is
  3653 recommended to convert to these new commands using isatool fixgoal
  3654 (backup your sources first!);
  3655 
  3656 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3657 the current theory context, and 'theory' to lookup stored theories;
  3658 
  3659 * new theory section 'locale' for declaring constants, assumptions and
  3660 definitions that have local scope;
  3661 
  3662 * new theory section 'nonterminals' for purely syntactic types;
  3663 
  3664 * new theory section 'setup' for generic ML setup functions
  3665 (e.g. package initialization);
  3666 
  3667 * the distribution now includes Isabelle icons: see
  3668 lib/logo/isabelle-{small,tiny}.xpm;
  3669 
  3670 * isatool install - install binaries with absolute references to
  3671 ISABELLE_HOME/bin;
  3672 
  3673 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3674 
  3675 * print mode 'emacs' reserved for Isamode;
  3676 
  3677 * support multiple print (ast) translations per constant name;
  3678 
  3679 * theorems involving oracles are now printed with a suffixed [!];
  3680 
  3681 
  3682 *** HOL ***
  3683 
  3684 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3685 
  3686 * HOL/inductive package reorganized and improved: now supports mutual
  3687 definitions such as
  3688 
  3689   inductive EVEN ODD
  3690     intrs
  3691       null "0 : EVEN"
  3692       oddI "n : EVEN ==> Suc n : ODD"
  3693       evenI "n : ODD ==> Suc n : EVEN"
  3694 
  3695 new theorem list "elims" contains an elimination rule for each of the
  3696 recursive sets; inductive definitions now handle disjunctive premises
  3697 correctly (also ZF);
  3698 
  3699 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3700 "mutual_induct" no longer exists - the induction rule is always
  3701 contained in "induct";
  3702 
  3703 
  3704 * HOL/datatype package re-implemented and greatly improved: now
  3705 supports mutually recursive datatypes such as
  3706 
  3707   datatype
  3708     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3709             | SUM ('a aexp) ('a aexp)
  3710             | DIFF ('a aexp) ('a aexp)
  3711             | NUM 'a
  3712   and
  3713     'a bexp = LESS ('a aexp) ('a aexp)
  3714             | AND ('a bexp) ('a bexp)
  3715             | OR ('a bexp) ('a bexp)
  3716 
  3717 as well as indirectly recursive datatypes such as
  3718 
  3719   datatype
  3720     ('a, 'b) term = Var 'a
  3721                   | App 'b ((('a, 'b) term) list)
  3722 
  3723 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  3724 induction on mutually / indirectly recursive datatypes.
  3725 
  3726 Primrec equations are now stored in theory and can be accessed via
  3727 <function_name>.simps.
  3728 
  3729 INCOMPATIBILITIES:
  3730 
  3731   - Theories using datatypes must now have theory Datatype as an
  3732     ancestor.
  3733   - The specific <typename>.induct_tac no longer exists - use the
  3734     generic induct_tac instead.
  3735   - natE has been renamed to nat.exhaust - use exhaust_tac
  3736     instead of res_inst_tac ... natE. Note that the variable
  3737     names in nat.exhaust differ from the names in natE, this
  3738     may cause some "fragile" proofs to fail.
  3739   - The theorems split_<typename>_case and split_<typename>_case_asm
  3740     have been renamed to <typename>.split and <typename>.split_asm.
  3741   - Since default sorts of type variables are now handled correctly,
  3742     some datatype definitions may have to be annotated with explicit
  3743     sort constraints.
  3744   - Primrec definitions no longer require function name and type
  3745     of recursive argument.
  3746 
  3747 Consider using isatool fixdatatype to adapt your theories and proof
  3748 scripts to the new package (backup your sources first!).
  3749 
  3750 
  3751 * HOL/record package: considerably improved implementation; now
  3752 includes concrete syntax for record types, terms, updates; theorems
  3753 for surjective pairing and splitting !!-bound record variables; proof
  3754 support is as follows:
  3755 
  3756   1) standard conversions (selectors or updates applied to record
  3757 constructor terms) are part of the standard simpset;
  3758 
  3759   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  3760 made part of standard simpset and claset via addIffs;
  3761 
  3762   3) a tactic for record field splitting (record_split_tac) is part of
  3763 the standard claset (addSWrapper);
  3764 
  3765 To get a better idea about these rules you may retrieve them via
  3766 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  3767 the name of your record type.
  3768 
  3769 The split tactic 3) conceptually simplifies by the following rule:
  3770 
  3771   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  3772 
  3773 Thus any record variable that is bound by meta-all will automatically
  3774 blow up into some record constructor term, consequently the
  3775 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  3776 solve record problems automatically.
  3777 
  3778 
  3779 * reorganized the main HOL image: HOL/Integ and String loaded by
  3780 default; theory Main includes everything;
  3781 
  3782 * automatic simplification of integer sums and comparisons, using cancellation;
  3783 
  3784 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  3785 
  3786 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  3787 
  3788 * many new identities for unions, intersections, set difference, etc.;
  3789 
  3790 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  3791 called split_if, split_split, split_sum_case and split_nat_case (to go
  3792 with add/delsplits);
  3793 
  3794 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  3795 (?x::unit) = (); this is made part of the default simpset, which COULD
  3796 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  3797 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  3798 unit_abs_eta_conv is added in order to counter the effect of
  3799 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  3800 %u.f();
  3801 
  3802 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3803 makes more sense);
  3804 
  3805 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3806   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3807   disjointness reasoning but breaking a few old proofs.
  3808 
  3809 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3810 to 'converse' from 'inverse' (for compatibility with ZF and some
  3811 literature);
  3812 
  3813 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3814 the well-founded relation;
  3815 
  3816 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3817     Compl A.  The "Compl" syntax remains available as input syntax for this
  3818     release ONLY.
  3819 
  3820 * HOL/Update: new theory of function updates:
  3821     f(a:=b) == %x. if x=a then b else f x
  3822 may also be iterated as in f(a:=b,c:=d,...);
  3823 
  3824 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  3825 
  3826 * HOL/List:
  3827   - new function list_update written xs[i:=v] that updates the i-th
  3828     list position. May also be iterated as in xs[i:=a,j:=b,...].
  3829   - new function `upt' written [i..j(] which generates the list
  3830     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  3831     bound write [i..j], which is a shorthand for [i..j+1(].
  3832   - new lexicographic orderings and corresponding wellfoundedness theorems.
  3833 
  3834 * HOL/Arith:
  3835   - removed 'pred' (predecessor) function;
  3836   - generalized some theorems about n-1;
  3837   - many new laws about "div" and "mod";
  3838   - new laws about greatest common divisors (see theory ex/Primes);
  3839 
  3840 * HOL/Relation: renamed the relational operator r^-1 "converse"
  3841 instead of "inverse";
  3842 
  3843 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  3844   of the multiset ordering;
  3845 
  3846 * directory HOL/Real: a construction of the reals using Dedekind cuts
  3847   (not included by default);
  3848 
  3849 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  3850 
  3851 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  3852   programs, i.e. different program variables may have different types.
  3853 
  3854 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3855   [previously, this check worked only if the rewrite rule was unconditional]
  3856   Now rew can involve either definitions or equalities (either == or =).
  3857 
  3858 
  3859 *** ZF ***
  3860 
  3861 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  3862   only the theorems proved on ZF.ML;
  3863 
  3864 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3865   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3866   disjointness reasoning but breaking a few old proofs.
  3867 
  3868 * ZF/Update: new theory of function updates
  3869     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  3870   may also be iterated as in f(a:=b,c:=d,...);
  3871 
  3872 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  3873 
  3874 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3875   [previously, this check worked only if the rewrite rule was unconditional]
  3876   Now rew can involve either definitions or equalities (either == or =).
  3877 
  3878 * case_tac provided for compatibility with HOL
  3879     (like the old excluded_middle_tac, but with subgoals swapped)
  3880 
  3881 
  3882 *** Internal programming interfaces ***
  3883 
  3884 * Pure: several new basic modules made available for general use, see
  3885 also src/Pure/README;
  3886 
  3887 * improved the theory data mechanism to support encapsulation (data
  3888 kind name replaced by private Object.kind, acting as authorization
  3889 key); new type-safe user interface via functor TheoryDataFun; generic
  3890 print_data function becomes basically useless;
  3891 
  3892 * removed global_names compatibility flag -- all theory declarations
  3893 are qualified by default;
  3894 
  3895 * module Pure/Syntax now offers quote / antiquote translation
  3896 functions (useful for Hoare logic etc. with implicit dependencies);
  3897 see HOL/ex/Antiquote for an example use;
  3898 
  3899 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  3900 cterm -> thm;
  3901 
  3902 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  3903 subgoal;
  3904 
  3905 * Display.print_goals function moved to Locale.print_goals;
  3906 
  3907 * standard print function for goals supports current_goals_markers
  3908 variable for marking begin of proof, end of proof, start of goal; the
  3909 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  3910 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  3911 for example;
  3912 
  3913 
  3914 
  3915 New in Isabelle98 (January 1998)
  3916 --------------------------------
  3917 
  3918 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3919 
  3920 * changed lexical syntax of terms / types: dots made part of long
  3921 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  3922 
  3923 * simpset (and claset) reference variable replaced by functions
  3924 simpset / simpset_ref;
  3925 
  3926 * no longer supports theory aliases (via merge) and non-trivial
  3927 implicit merge of thms' signatures;
  3928 
  3929 * most internal names of constants changed due to qualified names;
  3930 
  3931 * changed Pure/Sequence interface (see Pure/seq.ML);
  3932 
  3933 
  3934 *** General Changes ***
  3935 
  3936 * hierachically structured name spaces (for consts, types, axms, thms
  3937 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  3938 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  3939 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  3940 long_names for fully qualified output names; NOTE: ML programs
  3941 (special tactics, packages etc.) referring to internal names may have
  3942 to be adapted to cope with fully qualified names; in case of severe
  3943 backward campatibility problems try setting 'global_names' at compile
  3944 time to have enrything declared within a flat name space; one may also
  3945 fine tune name declarations in theories via the 'global' and 'local'
  3946 section;
  3947 
  3948 * reimplemented the implicit simpset and claset using the new anytype
  3949 data filed in signatures; references simpset:simpset ref etc. are
  3950 replaced by functions simpset:unit->simpset and
  3951 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  3952 to patch your ML files accordingly;
  3953 
  3954 * HTML output now includes theory graph data for display with Java
  3955 applet or isatool browser; data generated automatically via isatool
  3956 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  3957 
  3958 * defs may now be conditional; improved rewrite_goals_tac to handle
  3959 conditional equations;
  3960 
  3961 * defs now admits additional type arguments, using TYPE('a) syntax;
  3962 
  3963 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  3964 creates a new theory node; implicit merge of thms' signatures is
  3965 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  3966 transfer:theory->thm->thm in (rare) cases;
  3967 
  3968 * improved handling of draft signatures / theories; draft thms (and
  3969 ctyps, cterms) are automatically promoted to real ones;
  3970 
  3971 * slightly changed interfaces for oracles: admit many per theory, named
  3972 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  3973 
  3974 * print_goals: optional output of const types (set show_consts and
  3975 show_types);
  3976 
  3977 * improved output of warnings (###) and errors (***);
  3978 
  3979 * subgoal_tac displays a warning if the new subgoal has type variables;
  3980 
  3981 * removed old README and Makefiles;
  3982 
  3983 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  3984 
  3985 * removed obsolete init_pps and init_database;
  3986 
  3987 * deleted the obsolete tactical STATE, which was declared by
  3988     fun STATE tacfun st = tacfun st st;
  3989 
  3990 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  3991 (which abbreviates $HOME);
  3992 
  3993 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  3994 use isatool fixseq to adapt your ML programs (this works for fully
  3995 qualified references to the Sequence structure only!);
  3996 
  3997 * use_thy no longer requires writable current directory; it always
  3998 reloads .ML *and* .thy file, if either one is out of date;
  3999 
  4000 
  4001 *** Classical Reasoner ***
  4002 
  4003 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4004 tactics that use classical reasoning to simplify a subgoal without
  4005 splitting it into several subgoals;
  4006 
  4007 * Safe_tac: like safe_tac but uses the default claset;
  4008 
  4009 
  4010 *** Simplifier ***
  4011 
  4012 * added simplification meta rules:
  4013     (asm_)(full_)simplify: simpset -> thm -> thm;
  4014 
  4015 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4016 logics (again);
  4017 
  4018 * added prems argument to simplification procedures;
  4019 
  4020 * HOL, FOL, ZF: added infix function `addsplits':
  4021   instead of `<simpset> setloop (split_tac <thms>)'
  4022   you can simply write `<simpset> addsplits <thms>'
  4023 
  4024 
  4025 *** Syntax ***
  4026 
  4027 * TYPE('a) syntax for type reflection terms;
  4028 
  4029 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4030 
  4031 * pretty printer: changed order of mixfix annotation preference (again!);
  4032 
  4033 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4034 
  4035 
  4036 *** HOL ***
  4037 
  4038 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4039   with `addloop' of the simplifier to faciliate case splitting in premises.
  4040 
  4041 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4042 
  4043 * HOL/Auth: new protocol proofs including some for the Internet
  4044   protocol TLS;
  4045 
  4046 * HOL/Map: new theory of `maps' a la VDM;
  4047 
  4048 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4049 cancelling out common nat summands from =, <, <= (in)equalities, or
  4050 differences; simplification procedures nat_cancel_factor for
  4051 cancelling common factor from =, <, <= (in)equalities over natural
  4052 sums; nat_cancel contains both kinds of procedures, it is installed by
  4053 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4054 
  4055 * HOL/simplifier: terms of the form
  4056   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4057   are rewritten to
  4058   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4059   and those of the form
  4060   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4061   are rewritten to
  4062   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4063 
  4064 * HOL/datatype
  4065   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4066 
  4067   P(t_case f1 ... fn x) =
  4068      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4069         ...
  4070        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4071      )
  4072 
  4073   and a theorem `split_t_case_asm' 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   which can be added to a simpset via `addsplits'. The existing theorems
  4081   expand_list_case and expand_option_case have been renamed to
  4082   split_list_case and split_option_case.
  4083 
  4084 * HOL/Arithmetic:
  4085   - `pred n' is automatically converted to `n-1'.
  4086     Users are strongly encouraged not to use `pred' any longer,
  4087     because it will disappear altogether at some point.
  4088   - Users are strongly encouraged to write "0 < n" rather than
  4089     "n ~= 0". Theorems and proof tools have been modified towards this
  4090     `standard'.
  4091 
  4092 * HOL/Lists:
  4093   the function "set_of_list" has been renamed "set" (and its theorems too);
  4094   the function "nth" now takes its arguments in the reverse order and
  4095   has acquired the infix notation "!" as in "xs!n".
  4096 
  4097 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4098 
  4099 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4100   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4101 
  4102 * HOL/record: extensible records with schematic structural subtyping
  4103 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4104 still lacks various theorems and concrete record syntax;
  4105 
  4106 
  4107 *** HOLCF ***
  4108 
  4109 * removed "axioms" and "generated by" sections;
  4110 
  4111 * replaced "ops" section by extended "consts" section, which is capable of
  4112   handling the continuous function space "->" directly;
  4113 
  4114 * domain package:
  4115   . proves theorems immediately and stores them in the theory,
  4116   . creates hierachical name space,
  4117   . now uses normal mixfix annotations (instead of cinfix...),
  4118   . minor changes to some names and values (for consistency),
  4119   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4120   . separator between mutual domain defs: changed "," to "and",
  4121   . improved handling of sort constraints;  now they have to
  4122     appear on the left-hand side of the equations only;
  4123 
  4124 * fixed LAM <x,y,zs>.b syntax;
  4125 
  4126 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4127 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4128 
  4129 
  4130 *** FOL and ZF ***
  4131 
  4132 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4133   with `addloop' of the simplifier to faciliate case splitting in premises.
  4134 
  4135 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4136 in HOL, they strip ALL and --> from proved theorems;
  4137 
  4138 
  4139 
  4140 New in Isabelle94-8 (May 1997)
  4141 ------------------------------
  4142 
  4143 *** General Changes ***
  4144 
  4145 * new utilities to build / run / maintain Isabelle etc. (in parts
  4146 still somewhat experimental); old Makefiles etc. still functional;
  4147 
  4148 * new 'Isabelle System Manual';
  4149 
  4150 * INSTALL text, together with ./configure and ./build scripts;
  4151 
  4152 * reimplemented type inference for greater efficiency, better error
  4153 messages and clean internal interface;
  4154 
  4155 * prlim command for dealing with lots of subgoals (an easier way of
  4156 setting goals_limit);
  4157 
  4158 
  4159 *** Syntax ***
  4160 
  4161 * supports alternative (named) syntax tables (parser and pretty
  4162 printer); internal interface is provided by add_modesyntax(_i);
  4163 
  4164 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4165 be used in conjunction with the Isabelle symbol font; uses the
  4166 "symbols" syntax table;
  4167 
  4168 * added token_translation interface (may translate name tokens in
  4169 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4170 the current print_mode); IMPORTANT: user print translation functions
  4171 are responsible for marking newly introduced bounds
  4172 (Syntax.mark_boundT);
  4173 
  4174 * token translations for modes "xterm" and "xterm_color" that display
  4175 names in bold, underline etc. or colors (which requires a color
  4176 version of xterm);
  4177 
  4178 * infixes may now be declared with names independent of their syntax;
  4179 
  4180 * added typed_print_translation (like print_translation, but may
  4181 access type of constant);
  4182 
  4183 
  4184 *** Classical Reasoner ***
  4185 
  4186 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4187 some limitations.  Blast_tac...
  4188   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4189   + ignores elimination rules that don't have the correct format
  4190         (the conclusion MUST be a formula variable)
  4191   + ignores types, which can make HOL proofs fail
  4192   + rules must not require higher-order unification, e.g. apply_type in ZF
  4193     [message "Function Var's argument not a bound variable" relates to this]
  4194   + its proof strategy is more general but can actually be slower
  4195 
  4196 * substitution with equality assumptions no longer permutes other
  4197 assumptions;
  4198 
  4199 * minor changes in semantics of addafter (now called addaltern); renamed
  4200 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4201 (and access functions for it);
  4202 
  4203 * improved combination of classical reasoner and simplifier:
  4204   + functions for handling clasimpsets
  4205   + improvement of addss: now the simplifier is called _after_ the
  4206     safe steps.
  4207   + safe variant of addss called addSss: uses safe simplifications
  4208     _during_ the safe steps. It is more complete as it allows multiple
  4209     instantiations of unknowns (e.g. with slow_tac).
  4210 
  4211 *** Simplifier ***
  4212 
  4213 * added interface for simplification procedures (functions that
  4214 produce *proven* rewrite rules on the fly, depending on current
  4215 redex);
  4216 
  4217 * ordering on terms as parameter (used for ordered rewriting);
  4218 
  4219 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4220 
  4221 * the solver is now split into a safe and an unsafe part.
  4222 This should be invisible for the normal user, except that the
  4223 functions setsolver and addsolver have been renamed to setSolver and
  4224 addSolver; added safe_asm_full_simp_tac;
  4225 
  4226 
  4227 *** HOL ***
  4228 
  4229 * a generic induction tactic `induct_tac' which works for all datatypes and
  4230 also for type `nat';
  4231 
  4232 * a generic case distinction tactic `exhaust_tac' which works for all
  4233 datatypes and also for type `nat';
  4234 
  4235 * each datatype comes with a function `size';
  4236 
  4237 * patterns in case expressions allow tuple patterns as arguments to
  4238 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4239 
  4240 * primrec now also works with type nat;
  4241 
  4242 * recdef: a new declaration form, allows general recursive functions to be
  4243 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4244 
  4245 * the constant for negation has been renamed from "not" to "Not" to
  4246 harmonize with FOL, ZF, LK, etc.;
  4247 
  4248 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4249 infinite lists;
  4250 
  4251 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4252 
  4253 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4254 problems in commutative rings, using axiomatic type classes for + and *;
  4255 
  4256 * more examples in HOL/MiniML and HOL/Auth;
  4257 
  4258 * more default rewrite rules for quantifiers, union/intersection;
  4259 
  4260 * a new constant `arbitrary == @x.False';
  4261 
  4262 * HOLCF/IOA replaces old HOL/IOA;
  4263 
  4264 * HOLCF changes: derived all rules and arities
  4265   + axiomatic type classes instead of classes
  4266   + typedef instead of faking type definitions
  4267   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4268   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4269   + eliminated the types void, one, tr
  4270   + use unit lift and bool lift (with translations) instead of one and tr
  4271   + eliminated blift from Lift3.thy (use Def instead of blift)
  4272   all eliminated rules are derived as theorems --> no visible changes ;
  4273 
  4274 
  4275 *** ZF ***
  4276 
  4277 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4278 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4279 as ZF_cs addSIs [equalityI];
  4280 
  4281 
  4282 
  4283 New in Isabelle94-7 (November 96)
  4284 ---------------------------------
  4285 
  4286 * allowing negative levels (as offsets) in prlev and choplev;
  4287 
  4288 * super-linear speedup for large simplifications;
  4289 
  4290 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4291 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4292 FAIL); can suppress it using the command Delsimps (ex_simps @
  4293 all_simps); De Morgan laws are also now included, by default;
  4294 
  4295 * improved printing of ==>  :  ~:
  4296 
  4297 * new object-logic "Sequents" adds linear logic, while replacing LK
  4298 and Modal (thanks to Sara Kalvala);
  4299 
  4300 * HOL/Auth: correctness proofs for authentication protocols;
  4301 
  4302 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4303 examples on HOL/Auth);
  4304 
  4305 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4306 the rewriter and classical reasoner simultaneously;
  4307 
  4308 * function uresult no longer returns theorems in "standard" format;
  4309 regain previous version by: val uresult = standard o uresult;
  4310 
  4311 
  4312 
  4313 New in Isabelle94-6
  4314 -------------------
  4315 
  4316 * oracles -- these establish an interface between Isabelle and trusted
  4317 external reasoners, which may deliver results as theorems;
  4318 
  4319 * proof objects (in particular record all uses of oracles);
  4320 
  4321 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4322 
  4323 * "constdefs" section in theory files;
  4324 
  4325 * "primrec" section (HOL) no longer requires names;
  4326 
  4327 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4328 
  4329 
  4330 
  4331 New in Isabelle94-5
  4332 -------------------
  4333 
  4334 * reduced space requirements;
  4335 
  4336 * automatic HTML generation from theories;
  4337 
  4338 * theory files no longer require "..." (quotes) around most types;
  4339 
  4340 * new examples, including two proofs of the Church-Rosser theorem;
  4341 
  4342 * non-curried (1994) version of HOL is no longer distributed;
  4343 
  4344 
  4345 
  4346 New in Isabelle94-4
  4347 -------------------
  4348 
  4349 * greatly reduced space requirements;
  4350 
  4351 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4352 
  4353 * searchable theorem database (see the section "Retrieving theorems" on
  4354 page 8 of the Reference Manual);
  4355 
  4356 * new examples, including Grabczewski's monumental case study of the
  4357 Axiom of Choice;
  4358 
  4359 * The previous version of HOL renamed to Old_HOL;
  4360 
  4361 * The new version of HOL (previously called CHOL) uses a curried syntax
  4362 for functions.  Application looks like f a b instead of f(a,b);
  4363 
  4364 * Mutually recursive inductive definitions finally work in HOL;
  4365 
  4366 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4367 translates to the operator "split";
  4368 
  4369 
  4370 
  4371 New in Isabelle94-3
  4372 -------------------
  4373 
  4374 * new infix operator, addss, allowing the classical reasoner to
  4375 perform simplification at each step of its search.  Example:
  4376         fast_tac (cs addss ss)
  4377 
  4378 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4379 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4380 look like (a,b) instead of <a,b>;
  4381 
  4382 * PLEASE NOTE: CHOL will eventually replace HOL!
  4383 
  4384 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4385 It translates to the operator "split".  A new theory of integers is available;
  4386 
  4387 * In ZF, integer numerals now denote two's-complement binary integers.
  4388 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4389 
  4390 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4391 of the Axiom of Choice;
  4392 
  4393 
  4394 
  4395 New in Isabelle94-2
  4396 -------------------
  4397 
  4398 * Significantly faster resolution;
  4399 
  4400 * the different sections in a .thy file can now be mixed and repeated
  4401 freely;
  4402 
  4403 * Database of theorems for FOL, HOL and ZF.  New
  4404 commands including qed, qed_goal and bind_thm store theorems in the database.
  4405 
  4406 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4407 a given theory (thms_of), or find out what theory a theorem was proved in
  4408 (theory_of_thm);
  4409 
  4410 * Bugs fixed in the inductive definition and datatype packages;
  4411 
  4412 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4413 and HOL_dup_cs obsolete;
  4414 
  4415 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4416 have been removed;
  4417 
  4418 * Simpler definition of function space in ZF;
  4419 
  4420 * new results about cardinal and ordinal arithmetic in ZF;
  4421 
  4422 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4423 types;
  4424 
  4425 
  4426 $Id$