NEWS
author wenzelm
Tue Jul 25 21:18:04 2006 +0200 (2006-07-25)
changeset 20197 ffc64d90fc1f
parent 20188 8b22026445af
child 20217 25b068a99d2b
permissions -rw-r--r--
use Term.add_vars instead of obsolete term_varnames;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     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") are now
    19 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 
    32 *** Document preparation ***
    33 
    34 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    35 check the given source text as ML type/structure, printing verbatim.
    36 
    37 
    38 *** Pure ***
    39 
    40 * class_package.ML offers a combination of axclasses and locales to achieve
    41 Haskell-like type classes in Isabelle. See HOL/ex/Classpackage.thy for examples.
    42 
    43 * Yet another code generator framework allows to generate executable code
    44 for ML and Haskell (including "class"es). Most basic use cases:
    45 
    46     internal compilation:
    47         code_serialize ml <list of constants (term syntax)> (-)
    48     writing ML code to a file:
    49         code_serialize ml <list of constants (term syntax)> (<filename>)
    50     writing Haskell code to a bunch of files:
    51         code_serialize haskell <list of constants (term syntax)> (<filename>)
    52 
    53 See HOL/ex/Codegenerator.thy for examples.
    54 
    55 * Command 'no_translations' removes translation rules from theory
    56 syntax.
    57 
    58 * Overloaded definitions are now actually checked for acyclic
    59 dependencies.  The overloading scheme is slightly more general than
    60 that of Haskell98, although Isabelle does not demand an exact
    61 correspondence to type class and instance declarations.
    62 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
    63 exotic versions of overloading -- at the discretion of the user!
    64 
    65 Polymorphic constants are represented via type arguments, i.e. the
    66 instantiation that matches an instance against the most general
    67 declaration given in the signature.  For example, with the declaration
    68 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
    69 as c(nat).  Overloading is essentially simultaneous structural
    70 recursion over such type arguments.  Incomplete specification patterns
    71 impose global constraints on all occurrences, e.g. c('a * 'a) on the
    72 LHS means that more general c('a * 'b) will be disallowed on any RHS.
    73 Command 'print_theory' outputs the normalized system of recursive
    74 equations, see section "definitions".
    75 
    76 * Isar: improper proof element 'guess' is like 'obtain', but derives
    77 the obtained context from the course of reasoning!  For example:
    78 
    79   assume "EX x y. A x & B y"   -- "any previous fact"
    80   then guess x and y by clarify
    81 
    82 This technique is potentially adventurous, depending on the facts and
    83 proof tools being involved here.
    84 
    85 * Isar: known facts from the proof context may be specified as literal
    86 propositions, using ASCII back-quote syntax.  This works wherever
    87 named facts used to be allowed so far, in proof commands, proof
    88 methods, attributes etc.  Literal facts are retrieved from the context
    89 according to unification of type and term parameters.  For example,
    90 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
    91 theorems in the current context, then these are valid literal facts:
    92 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
    93 
    94 There is also a proof method "fact" which does the same composition
    95 for explicit goal states, e.g. the following proof texts coincide with
    96 certain special cases of literal facts:
    97 
    98   have "A" by fact                 ==  note `A`
    99   have "A ==> B" by fact           ==  note `A ==> B`
   100   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   101   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   102 
   103 * Isar: ":" (colon) is no longer a symbolic identifier character in
   104 outer syntax.  Thus symbolic identifiers may be used without
   105 additional white space in declarations like this: ``assume *: A''.
   106 
   107 * Isar: 'print_facts' prints all local facts of the current context,
   108 both named and unnamed ones.
   109 
   110 * Isar: 'def' now admits simultaneous definitions, e.g.:
   111 
   112   def x == "t" and y == "u"
   113 
   114 * Isar: added command 'unfolding', which is structurally similar to
   115 'using', but affects both the goal state and facts by unfolding given
   116 rewrite rules.  Thus many occurrences of the 'unfold' method or
   117 'unfolded' attribute may be replaced by first-class proof text.
   118 
   119 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   120 and command 'unfolding' now all support object-level equalities
   121 (potentially conditional).  The underlying notion of rewrite rule is
   122 analogous to the 'rule_format' attribute, but *not* that of the
   123 Simplifier (which is usually more generous).
   124 
   125 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   126 method expression within a sandbox consisting of the first N
   127 sub-goals, which need to exist.  For example, ``simp_all [3]''
   128 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   129 simplifies all new goals that emerge from applying rule foo to the
   130 originally first one.
   131 
   132 * Isar: schematic goals are no longer restricted to higher-order
   133 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   134 expected.
   135 
   136 * Isar: the conclusion of a long theorem statement is now either
   137 'shows' (a simultaneous conjunction, as before), or 'obtains'
   138 (essentially a disjunction of cases with local parameters and
   139 assumptions).  The latter allows to express general elimination rules
   140 adequately; in this notation common elimination rules look like this:
   141 
   142   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   143     assumes "EX x. P x"
   144     obtains x where "P x"
   145 
   146   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   147     assumes "A & B"
   148     obtains A and B
   149 
   150   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   151     assumes "A | B"
   152     obtains
   153       A
   154     | B
   155 
   156 The subsequent classical rules even refer to the formal "thesis"
   157 explicitly:
   158 
   159   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   160     obtains "~ thesis"
   161 
   162   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   163     obtains "thesis ==> something"
   164 
   165 The actual proof of an 'obtains' statement is analogous to that of the
   166 Isar proof element 'obtain', only that there may be several cases.
   167 Optional case names may be specified in parentheses; these will be
   168 available both in the present proof and as annotations in the
   169 resulting rule, for later use with the 'cases' method (cf. attribute
   170 case_names).
   171 
   172 * Isar: 'print_statement' prints theorems from the current theory or
   173 proof context in long statement form, according to the syntax of a
   174 top-level lemma.
   175 
   176 * Isar: 'obtain' takes an optional case name for the local context
   177 introduction rule (default "that").
   178 
   179 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   180 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   181 to occur.
   182 
   183 * Pure: syntax "CONST name" produces a fully internalized constant
   184 according to the current context.  This is particularly useful for
   185 syntax translations that should refer to internal constant
   186 representations independently of name spaces.
   187 
   188 * Isar/locales: 'const_syntax' provides a robust interface to the
   189 'syntax' primitive that also works in a locale context.  Type
   190 declaration and internal syntactic representation of given constants
   191 retrieved from the context.
   192 
   193 * Isar/locales: new derived specification elements 'axiomatization',
   194 'definition', 'abbreviation', which support type-inference, admit
   195 object-level specifications (equality, equivalence).  See also the
   196 isar-ref manual.  Examples:
   197 
   198   axiomatization
   199     eq  (infix "===" 50)
   200     where eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   201 
   202   definition
   203     "f x y = x + y + 1"
   204     "g x = f x x"
   205 
   206   abbreviation
   207     neq  (infix "=!=" 50)
   208     "x =!= y == ~ (x === y)"
   209 
   210 These specifications may be also used in a locale context.  Then the
   211 constants being introduced depend on certain fixed parameters, and the
   212 constant name is qualified by the locale base name.  An internal
   213 abbreviation takes care for convenient input and output, making the
   214 parameters implicit and using the original short name.  See also
   215 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   216 entities from a monomorphic theory.
   217 
   218 Presently, abbreviations are only available 'in' a target locale, but
   219 not inherited by general import expressions.  Also note that
   220 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   221 'translations' in common applications.
   222 
   223 Concrete syntax is attached to specified constants in internal form,
   224 independently of name spaces.  The parse tree representation is
   225 slightly different -- use 'const_syntax' instead of raw 'syntax', and
   226 'translations' with explicit "CONST" markup to accommodate this.
   227 
   228 * Isar/locales: improved parameter handling:
   229 - use of locales "var" and "struct" no longer necessary;
   230 - parameter renamings are no longer required to be injective.
   231   This enables, for example, to define a locale for endomorphisms thus:
   232   locale endom = homom mult mult h.
   233 
   234 * Isar/locales: changed the way locales with predicates are defined.
   235 Instead of accumulating the specification, the imported expression is
   236 now an interpretation.
   237 INCOMPATIBILITY: different normal form of locale expressions.
   238 In particular, in interpretations of locales with predicates,
   239 goals repesenting already interpreted fragments are not removed
   240 automatically.  Use methods `intro_locales' and `unfold_locales'; see below.
   241 
   242 * Isar/locales: new methods `intro_locales' and `unfold_locales' provide
   243 backward reasoning on locales predicates.  The methods are aware of
   244 interpretations and discharge corresponding goals.  `intro_locales' is
   245 less aggressive then `unfold_locales' and does not unfold predicates to
   246 assumptions.
   247 
   248 * Isar/locales: the order in which locale fragments are accumulated
   249 has changed.  This enables to override declarations from fragments
   250 due to interpretations -- for example, unwanted simp rules.
   251 
   252 * Provers/induct: improved internal context management to support
   253 local fixes and defines on-the-fly.  Thus explicit meta-level
   254 connectives !! and ==> are rarely required anymore in inductive goals
   255 (using object-logic connectives for this purpose has been long
   256 obsolete anyway).  The subsequent proof patterns illustrate advanced
   257 techniques of natural induction; general datatypes and inductive sets
   258 work analogously (see also src/HOL/Lambda for realistic examples).
   259 
   260 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   261 parameters:
   262 
   263   lemma
   264     fixes n :: nat and x :: 'a
   265     assumes a: "A n x"
   266     shows "P n x"
   267     using a                     -- {* make induct insert fact a *}
   268   proof (induct n fixing: x)    -- {* generalize goal to "!!x. A n x ==> P n x" *}
   269     case 0
   270     show ?case sorry
   271   next
   272     case (Suc n)
   273     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   274     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   275     show ?case sorry
   276   qed
   277 
   278 (2) This is how to perform induction over ``expressions of a certain
   279 form'', using a locally defined inductive parameter n == "a x"
   280 together with strengthening (the latter is usually required to get
   281 sufficiently flexible induction hypotheses):
   282 
   283   lemma
   284     fixes a :: "'a => nat"
   285     assumes a: "A (a x)"
   286     shows "P (a x)"
   287     using a
   288   proof (induct n == "a x" fixing: x)
   289     ...
   290 
   291 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   292 particular technique.
   293 
   294 (3) This is how to perform existential reasoning ('obtains' or
   295 'obtain') by induction, while avoiding explicit object-logic
   296 encodings:
   297 
   298   lemma
   299     fixes n :: nat
   300     obtains x :: 'a where "P n x" and "Q n x"
   301   proof (induct n fixing: thesis)
   302     case 0
   303     obtain x where "P 0 x" and "Q 0 x" sorry
   304     then show thesis by (rule 0)
   305   next
   306     case (Suc n)
   307     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   308     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   309     then show thesis by (rule Suc.prems)
   310   qed
   311 
   312 Here the 'fixing: thesis' specification essentially modifies the scope
   313 of the formal thesis parameter, in order to the get the whole
   314 existence statement through the induction as expected.
   315 
   316 * Provers/induct: mutual induction rules are now specified as a list
   317 of rule sharing the same induction cases.  HOL packages usually
   318 provide foo_bar.inducts for mutually defined items foo and bar
   319 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   320 specify mutual induction rules differently, i.e. like this:
   321 
   322   (induct rule: foo_bar.inducts)
   323   (induct set: foo bar)
   324   (induct type: foo bar)
   325 
   326 The ML function ProjectRule.projections turns old-style rules into the
   327 new format.
   328 
   329 * Provers/induct: improved handling of simultaneous goals.  Instead of
   330 introducing object-level conjunction, the statement is now split into
   331 several conclusions, while the corresponding symbolic cases are
   332 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   333 explicitly.  For example:
   334 
   335   lemma
   336     fixes n :: nat
   337     shows "P n" and "Q n"
   338   proof (induct n)
   339     case 0 case 1
   340     show "P 0" sorry
   341   next
   342     case 0 case 2
   343     show "Q 0" sorry
   344   next
   345     case (Suc n) case 1
   346     note `P n` and `Q n`
   347     show "P (Suc n)" sorry
   348   next
   349     case (Suc n) case 2
   350     note `P n` and `Q n`
   351     show "Q (Suc n)" sorry
   352   qed
   353 
   354 The split into subcases may be deferred as follows -- this is
   355 particularly relevant for goal statements with local premises.
   356 
   357   lemma
   358     fixes n :: nat
   359     shows "A n ==> P n" and "B n ==> Q n"
   360   proof (induct n)
   361     case 0
   362     {
   363       case 1
   364       note `A 0`
   365       show "P 0" sorry
   366     next
   367       case 2
   368       note `B 0`
   369       show "Q 0" sorry
   370     }
   371   next
   372     case (Suc n)
   373     note `A n ==> P n` and `B n ==> Q n`
   374     {
   375       case 1
   376       note `A (Suc n)`
   377       show "P (Suc n)" sorry
   378     next
   379       case 2
   380       note `B (Suc n)`
   381       show "Q (Suc n)" sorry
   382     }
   383   qed
   384 
   385 If simultaneous goals are to be used with mutual rules, the statement
   386 needs to be structured carefully as a two-level conjunction, using
   387 lists of propositions separated by 'and':
   388 
   389   lemma
   390     shows "a : A ==> P1 a"
   391           "a : A ==> P2 a"
   392       and "b : B ==> Q1 b"
   393           "b : B ==> Q2 b"
   394           "b : B ==> Q3 b"
   395   proof (induct set: A B)
   396 
   397 * Provers/induct: support coinduction as well.  See
   398 src/HOL/Library/Coinductive_List.thy for various examples.
   399 
   400 * Simplifier: by default the simplifier trace only shows top level rewrites
   401 now. That is, trace_simp_depth_limit is set to 1 by default. Thus there is
   402 less danger of being flooded by the trace. The trace indicates where parts
   403 have been suppressed.
   404   
   405 * Provers/classical: removed obsolete classical version of elim_format
   406 attribute; classical elim/dest rules are now treated uniformly when
   407 manipulating the claset.
   408 
   409 * Provers/classical: stricter checks to ensure that supplied intro,
   410 dest and elim rules are well-formed; dest and elim rules must have at
   411 least one premise.
   412 
   413 * Provers/classical: attributes dest/elim/intro take an optional
   414 weight argument for the rule (just as the Pure versions).  Weights are
   415 ignored by automated tools, but determine the search order of single
   416 rule steps.
   417 
   418 * Syntax: input syntax now supports dummy variable binding "%_. b",
   419 where the body does not mention the bound variable.  Note that dummy
   420 patterns implicitly depend on their context of bounds, which makes
   421 "{_. _}" match any set comprehension as expected.  Potential
   422 INCOMPATIBILITY -- parse translations need to cope with syntactic
   423 constant "_idtdummy" in the binding position.
   424 
   425 * Syntax: removed obsolete syntactic constant "_K" and its associated
   426 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   427 for example "A -> B" => "Pi A (%_. B)".
   428 
   429 
   430 *** HOL ***
   431 
   432 * New top level command 'normal_form' computes the normal form of a term
   433 that may contain free variables. For example 'normal_form "rev[a,b,c]"'
   434 prints '[b,c,a]'. This command is suitable for heavy-duty computations
   435 because the functions are compiled to ML first.
   436 INCOMPATIBILITY: new keywords 'normal_form' must quoted when used as
   437 an identifier.
   438 
   439 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   440 25 like -->); output depends on the "iff" print_mode, the default is
   441 "A = B" (with priority 50).
   442 
   443 * Renamed constants in HOL.thy and Orderings.thy:
   444     op +   ~> HOL.plus
   445     op -   ~> HOL.minus
   446     uminus ~> HOL.uminus
   447     op *   ~> HOL.times
   448     op <   ~> Orderings.less
   449     op <=  ~> Orderings.less_eq
   450 
   451 Adaptions may be required in the following cases:
   452 
   453 a) User-defined constants using any of the names "plus", "minus", "times",
   454 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   455 may go wrong.
   456 INCOMPATIBILITY: use more specific names.
   457 
   458 b) Variables named "plus", "minus", "times", "less", "less_eq"
   459 INCOMPATIBILITY: use more specific names.
   460 
   461 c) Permutative equations (e.g. "a + b = b + a")
   462 Since the change of names also changes the order of terms, permutative
   463 rewrite rules may get applied in a different order. Experience shows that
   464 this is rarely the case (only two adaptions in the whole Isabelle
   465 distribution).
   466 INCOMPATIBILITY: rewrite proofs
   467 
   468 d) ML code directly refering to constant names
   469 This in general only affects hand-written proof tactics, simprocs and so on.
   470 INCOMPATIBILITY: grep your sourcecode and replace names.
   471 
   472 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   473 
   474 * The old set interval syntax "{m..n(}" (and relatives) has been removed.
   475   Use "{m..<n}" (and relatives) instead.
   476 
   477 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   478 "t = s" to False (by simproc "neq_simproc").  For backward
   479 compatibility this can be disabled by ML "reset use_neq_simproc".
   480 
   481 * "m dvd n" where m and n are numbers is evaluated to True/False by simp.
   482 
   483 * Theorem Cons_eq_map_conv no longer has attribute `simp'.
   484 
   485 * Theorem setsum_mult renamed to setsum_right_distrib.
   486 
   487 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   488 'rule' method.
   489 
   490 * Tactics 'sat' and 'satx' reimplemented, several improvements: goals
   491 no longer need to be stated as "<prems> ==> False", equivalences (i.e.
   492 "=" on type bool) are handled, variable names of the form "lit_<n>"
   493 are no longer reserved, significant speedup.
   494 
   495 * Tactics 'sat' and 'satx' can now replay MiniSat proof traces.  zChaff is
   496 still supported as well.
   497 
   498 * inductive and datatype: provide projections of mutual rules, bundled
   499 as foo_bar.inducts;
   500 
   501 * Library: theory Accessible_Part has been move to main HOL.
   502 
   503 * Library: added theory Coinductive_List of potentially infinite lists
   504 as greatest fixed-point.
   505 
   506 * Library: added theory AssocList which implements (finite) maps as
   507 association lists.
   508 
   509 * New proof method "evaluation" for efficiently solving a goal
   510   (i.e. a boolean expression) by compiling it to ML. The goal is
   511   "proved" (via the oracle "Evaluation") if it evaluates to True.
   512 
   513 * Support for hex (0x20) and binary (0b1001) numerals. 
   514 
   515 *** HOL-Algebra ***
   516 
   517 * Method algebra is now set up via an attribute.  For examples see CRing.thy.
   518   INCOMPATIBILITY: the method is now weaker on combinations of algebraic structures.
   519 
   520 *** HOL-Complex ***
   521 
   522 * Theory Real: new method ferrack implements quantifier elimination
   523 for linear arithmetic over the reals. The quantifier elimination
   524 feature is used only for decision, for compatibility with arith. This
   525 means a goal is either solved or left unchanged, no simplification.
   526 
   527 
   528 *** ML ***
   529 
   530 * Pure/library:
   531 
   532   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   533   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   534 
   535 The semantics of "burrow" is: "take a function with *simulatanously*
   536 transforms a list of value, and apply it *simulatanously* to a list of
   537 list of values of the appropriate type". Confer this with "map" which
   538 would *not* apply its argument function simulatanously but in
   539 sequence. "fold_burrow" has an additional context.
   540 
   541 Both actually avoid the usage of "unflat" since they hide away
   542 "unflat" from the user.
   543 
   544 * Pure/library: functions map2 and fold2 with curried syntax for
   545 simultanous mapping and folding:
   546 
   547     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   548     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   549 
   550 * Pure/library: indexed lists - some functions in the Isabelle library
   551 treating lists over 'a as finite mappings from [0...n] to 'a have been
   552 given more convenient names and signatures reminiscent of similar
   553 functions for alists, tables, etc:
   554 
   555   val nth: 'a list -> int -> 'a 
   556   val nth_update: int * 'a -> 'a list -> 'a list
   557   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   558   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   559 
   560 Note that fold_index starts counting at index 0, not 1 like foldln
   561 used to.
   562 
   563 * Pure/library: general ``divide_and_conquer'' combinator on lists.
   564 
   565 * Pure/General/name_mangler.ML provides a functor for generic name
   566 mangling (bijective mapping from any expression values to strings).
   567 
   568 * Pure/General/rat.ML implements rational numbers.
   569 
   570 * Pure/General/table.ML: the join operations now works via exceptions
   571 DUP/SAME instead of type option.  This is simpler in simple cases, and
   572 admits slightly more efficient complex applications.
   573 
   574 * Pure: datatype Context.generic joins theory/Proof.context and
   575 provides some facilities for code that works in either kind of
   576 context, notably GenericDataFun for uniform theory and proof data.
   577 
   578 * Pure: 'advanced' translation functions (parse_translation etc.) now
   579 use Context.generic instead of just theory.
   580 
   581 * Pure: simplified internal attribute type, which is now always
   582 Context.generic * thm -> Context.generic * thm.  Global (theory)
   583 vs. local (Proof.context) attributes have been discontinued, while
   584 minimizing code duplication.  Thm.rule_attribute and
   585 Thm.declaration_attribute build canonical attributes; see also
   586 structure Context for further operations on Context.generic, notably
   587 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   588 declarations and definitions.
   589 
   590 * Pure/kernel: consts certification ignores sort constraints given in
   591 signature declarations.  (This information is not relevant to the
   592 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE.
   593 
   594 * Pure: axiomatic type classes are now purely definitional, with
   595 explicit proofs of class axioms and super class relations performed
   596 internally.  See Pure/axclass.ML for the main internal interfaces --
   597 notably AxClass.define_class supercedes AxClass.add_axclass, and
   598 AxClass.axiomatize_class/classrel/arity supercede
   599 Sign.add_classes/classrel/arities.
   600 
   601 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
   602 global/local versions on theory vs. Proof.context have been
   603 discontinued; Attrib.syntax and Method.syntax have been adapted
   604 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
   605 attributes, methods, etc.
   606 
   607 * Pure: several functions of signature "... -> theory -> theory * ..."
   608 have been reoriented to "... -> theory -> ... * theory" in order to
   609 allow natural usage in combination with the ||>, ||>>, |-> and
   610 fold_map combinators.
   611 
   612 * Pure: primitive rule lift_rule now takes goal cterm instead of an
   613 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
   614 achieve the old behaviour.
   615 
   616 * Pure: the "Goal" constant is now called "prop", supporting a
   617 slightly more general idea of ``protecting'' meta-level rule
   618 statements.
   619 
   620 * Pure: Logic.(un)varify only works in a global context, which is now
   621 enforced instead of silently assumed.  INCOMPATIBILITY, may use
   622 Logic.legacy_(un)varify as temporary workaround.
   623 
   624 * Pure: structure Name provides scalable operations for generating
   625 internal variable names, notably Name.variants etc.  This replaces
   626 some popular functions from term.ML:
   627 
   628   Term.variant		->  Name.variant
   629   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
   630   Term.invent_names	->  Name.invent_list
   631 
   632 Note that low-level renaming rarely occurs in new code -- operations
   633 from structure Variable are used instead (see below).
   634 
   635 * Pure: structure Variable provides fundamental operations for proper
   636 treatment of fixed/schematic variables in a context.  For example,
   637 Variable.import introduces fixes for schematics of given facts and
   638 Variable.export reverses the effect (up to renaming) -- this replaces
   639 various freeze_thaw operations.
   640 
   641 * Pure: structure Goal provides simple interfaces for
   642 init/conclude/finish and tactical prove operations (replacing former
   643 Tactic.prove).  Goal.prove is the canonical way to prove results
   644 within a given context; Goal.prove_global is a degraded version for
   645 theory level goals, including a global Drule.standard.  Note that
   646 OldGoals.prove_goalw_cterm has long been obsolete, since it is
   647 ill-behaved in a local proof context (e.g. with local fixes/assumes or
   648 in a locale context).
   649 
   650 * Isar: simplified treatment of user-level errors, using exception
   651 ERROR of string uniformly.  Function error now merely raises ERROR,
   652 without any side effect on output channels.  The Isar toplevel takes
   653 care of proper display of ERROR exceptions.  ML code may use plain
   654 handle/can/try; cat_error may be used to concatenate errors like this:
   655 
   656   ... handle ERROR msg => cat_error msg "..."
   657 
   658 Toplevel ML code (run directly or through the Isar toplevel) may be
   659 embedded into the Isar toplevel with exception display/debug like
   660 this:
   661 
   662   Isar.toplevel (fn () => ...)
   663 
   664 INCOMPATIBILITY, removed special transform_error facilities, removed
   665 obsolete variants of user-level exceptions (ERROR_MESSAGE,
   666 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
   667 -- use plain ERROR instead.
   668 
   669 * Isar: theory setup now has type (theory -> theory), instead of a
   670 list.  INCOMPATIBILITY, may use #> to compose setup functions.
   671 
   672 * Isar: installed ML toplevel pretty printer for type Proof.context,
   673 subject to ProofContext.debug/verbose flags.
   674 
   675 * Isar: Toplevel.theory_to_proof admits transactions that modify the
   676 theory before entering a proof state.  Transactions now always see a
   677 quasi-functional intermediate checkpoint, both in interactive and
   678 batch mode.
   679 
   680 * Simplifier: the simpset of a running simplification process now
   681 contains a proof context (cf. Simplifier.the_context), which is the
   682 very context that the initial simpset has been retrieved from (by
   683 simpset_of/local_simpset_of).  Consequently, all plug-in components
   684 (solver, looper etc.) may depend on arbitrary proof data.
   685 
   686 * Simplifier.inherit_context inherits the proof context (plus the
   687 local bounds) of the current simplification process; any simproc
   688 etc. that calls the Simplifier recursively should do this!  Removed
   689 former Simplifier.inherit_bounds, which is already included here --
   690 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
   691 specify an explicit context using Simplifier.context/theory_context.
   692 
   693 * Simplifier/Classical Reasoner: more abstract interfaces
   694 change_simpset/claset for modifying the simpset/claset reference of a
   695 theory; raw versions simpset/claset_ref etc. have been discontinued --
   696 INCOMPATIBILITY.
   697 
   698 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
   699 "Trueprop" etc.
   700 
   701 
   702 
   703 New in Isabelle2005 (October 2005)
   704 ----------------------------------
   705 
   706 *** General ***
   707 
   708 * Theory headers: the new header syntax for Isar theories is
   709 
   710   theory <name>
   711   imports <theory1> ... <theoryN>
   712   uses <file1> ... <fileM>
   713   begin
   714 
   715 where the 'uses' part is optional.  The previous syntax
   716 
   717   theory <name> = <theory1> + ... + <theoryN>:
   718 
   719 will disappear in the next release.  Use isatool fixheaders to convert
   720 existing theory files.  Note that there is no change in ancient
   721 non-Isar theories now, but these will disappear soon.
   722 
   723 * Theory loader: parent theories can now also be referred to via
   724 relative and absolute paths.
   725 
   726 * Command 'find_theorems' searches for a list of criteria instead of a
   727 list of constants. Known criteria are: intro, elim, dest, name:string,
   728 simp:term, and any term. Criteria can be preceded by '-' to select
   729 theorems that do not match. Intro, elim, dest select theorems that
   730 match the current goal, name:s selects theorems whose fully qualified
   731 name contain s, and simp:term selects all simplification rules whose
   732 lhs match term.  Any other term is interpreted as pattern and selects
   733 all theorems matching the pattern. Available in ProofGeneral under
   734 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
   735 
   736   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
   737 
   738 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   739 matching the current goal as introduction rule and not having "HOL."
   740 in their name (i.e. not being defined in theory HOL).
   741 
   742 * Command 'thms_containing' has been discontinued in favour of
   743 'find_theorems'; INCOMPATIBILITY.
   744 
   745 * Communication with Proof General is now 8bit clean, which means that
   746 Unicode text in UTF-8 encoding may be used within theory texts (both
   747 formal and informal parts).  Cf. option -U of the Isabelle Proof
   748 General interface.  Here are some simple examples (cf. src/HOL/ex):
   749 
   750   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
   751   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
   752 
   753 * Improved efficiency of the Simplifier and, to a lesser degree, the
   754 Classical Reasoner.  Typical big applications run around 2 times
   755 faster.
   756 
   757 
   758 *** Document preparation ***
   759 
   760 * Commands 'display_drafts' and 'print_drafts' perform simple output
   761 of raw sources.  Only those symbols that do not require additional
   762 LaTeX packages (depending on comments in isabellesym.sty) are
   763 displayed properly, everything else is left verbatim.  isatool display
   764 and isatool print are used as front ends (these are subject to the
   765 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
   766 
   767 * Command tags control specific markup of certain regions of text,
   768 notably folding and hiding.  Predefined tags include "theory" (for
   769 theory begin and end), "proof" for proof commands, and "ML" for
   770 commands involving ML code; the additional tags "visible" and
   771 "invisible" are unused by default.  Users may give explicit tag
   772 specifications in the text, e.g. ''by %invisible (auto)''.  The
   773 interpretation of tags is determined by the LaTeX job during document
   774 preparation: see option -V of isatool usedir, or options -n and -t of
   775 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
   776 \isadroptag.
   777 
   778 Several document versions may be produced at the same time via isatool
   779 usedir (the generated index.html will link all of them).  Typical
   780 specifications include ''-V document=theory,proof,ML'' to present
   781 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
   782 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
   783 these parts without any formal replacement text.  The Isabelle site
   784 default settings produce ''document'' and ''outline'' versions as
   785 specified above.
   786 
   787 * Several new antiquotations:
   788 
   789   @{term_type term} prints a term with its type annotated;
   790 
   791   @{typeof term} prints the type of a term;
   792 
   793   @{const const} is the same as @{term const}, but checks that the
   794   argument is a known logical constant;
   795 
   796   @{term_style style term} and @{thm_style style thm} print a term or
   797   theorem applying a "style" to it
   798 
   799   @{ML text}
   800 
   801 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
   802 definitions, equations, inequations etc., 'concl' printing only the
   803 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
   804 to print the specified premise.  TermStyle.add_style provides an ML
   805 interface for introducing further styles.  See also the "LaTeX Sugar"
   806 document practical applications.  The ML antiquotation prints
   807 type-checked ML expressions verbatim.
   808 
   809 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
   810 and 'text' support optional locale specification '(in loc)', which
   811 specifies the default context for interpreting antiquotations.  For
   812 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
   813 
   814 * Option 'locale=NAME' of antiquotations specifies an alternative
   815 context interpreting the subsequent argument.  For example: @{thm
   816 [locale=lattice] inf_assoc}.
   817 
   818 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
   819 a proof context.
   820 
   821 * Proper output of antiquotations for theory commands involving a
   822 proof context (such as 'locale' or 'theorem (in loc) ...').
   823 
   824 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
   825 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
   826 
   827 * isatool usedir: new option -C (default true) controls whether option
   828 -D should include a copy of the original document directory; -C false
   829 prevents unwanted effects such as copying of administrative CVS data.
   830 
   831 
   832 *** Pure ***
   833 
   834 * Considerably improved version of 'constdefs' command.  Now performs
   835 automatic type-inference of declared constants; additional support for
   836 local structure declarations (cf. locales and HOL records), see also
   837 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
   838 sequential dependencies of definitions within a single 'constdefs'
   839 section; moreover, the declared name needs to be an identifier.  If
   840 all fails, consider to fall back on 'consts' and 'defs' separately.
   841 
   842 * Improved indexed syntax and implicit structures.  First of all,
   843 indexed syntax provides a notational device for subscripted
   844 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
   845 expressions.  Secondly, in a local context with structure
   846 declarations, number indexes \<^sub>n or the empty index (default
   847 number 1) refer to a certain fixed variable implicitly; option
   848 show_structs controls printing of implicit structures.  Typical
   849 applications of these concepts involve record types and locales.
   850 
   851 * New command 'no_syntax' removes grammar declarations (and
   852 translations) resulting from the given syntax specification, which is
   853 interpreted in the same manner as for the 'syntax' command.
   854 
   855 * 'Advanced' translation functions (parse_translation etc.) may depend
   856 on the signature of the theory context being presently used for
   857 parsing/printing, see also isar-ref manual.
   858 
   859 * Improved 'oracle' command provides a type-safe interface to turn an
   860 ML expression of type theory -> T -> term into a primitive rule of
   861 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
   862 is already included here); see also FOL/ex/IffExample.thy;
   863 INCOMPATIBILITY.
   864 
   865 * axclass: name space prefix for class "c" is now "c_class" (was "c"
   866 before); "cI" is no longer bound, use "c.intro" instead.
   867 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
   868 axclasses vs. locales.
   869 
   870 * Improved internal renaming of symbolic identifiers -- attach primes
   871 instead of base 26 numbers.
   872 
   873 * New flag show_question_marks controls printing of leading question
   874 marks in schematic variable names.
   875 
   876 * In schematic variable names, *any* symbol following \<^isub> or
   877 \<^isup> is now treated as part of the base name.  For example, the
   878 following works without printing of awkward ".0" indexes:
   879 
   880   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   881     by simp
   882 
   883 * Inner syntax includes (*(*nested*) comments*).
   884 
   885 * Pretty printer now supports unbreakable blocks, specified in mixfix
   886 annotations as "(00...)".
   887 
   888 * Clear separation of logical types and nonterminals, where the latter
   889 may only occur in 'syntax' specifications or type abbreviations.
   890 Before that distinction was only partially implemented via type class
   891 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
   892 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
   893 exotic syntax specifications may require further adaption
   894 (e.g. Cube/Cube.thy).
   895 
   896 * Removed obsolete type class "logic", use the top sort {} instead.
   897 Note that non-logical types should be declared as 'nonterminals'
   898 rather than 'types'.  INCOMPATIBILITY for new object-logic
   899 specifications.
   900 
   901 * Attributes 'induct' and 'cases': type or set names may now be
   902 locally fixed variables as well.
   903 
   904 * Simplifier: can now control the depth to which conditional rewriting
   905 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
   906 Limit.
   907 
   908 * Simplifier: simplification procedures may now take the current
   909 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   910 interface), which is very useful for calling the Simplifier
   911 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
   912 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
   913 low-level mk_simproc no longer applies Logic.varify internally, to
   914 allow for use in a context of fixed variables.
   915 
   916 * thin_tac now works even if the assumption being deleted contains !!
   917 or ==>.  More generally, erule now works even if the major premise of
   918 the elimination rule contains !! or ==>.
   919 
   920 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
   921 
   922 * Reorganized bootstrapping of the Pure theories; CPure is now derived
   923 from Pure, which contains all common declarations already.  Both
   924 theories are defined via plain Isabelle/Isar .thy files.
   925 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   926 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
   927 use isatool fixcpure to adapt your theory and ML sources.
   928 
   929 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
   930 selections of theorems in named facts via index ranges.
   931 
   932 * 'print_theorems': in theory mode, really print the difference
   933 wrt. the last state (works for interactive theory development only),
   934 in proof mode print all local facts (cf. 'print_facts');
   935 
   936 * 'hide': option '(open)' hides only base names.
   937 
   938 * More efficient treatment of intermediate checkpoints in interactive
   939 theory development.
   940 
   941 * Code generator is now invoked via code_module (incremental code
   942 generation) and code_library (modular code generation, ML structures
   943 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
   944 must be quoted when used as identifiers.
   945 
   946 * New 'value' command for reading, evaluating and printing terms using
   947 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
   948 quoted when used as identifier.
   949 
   950 
   951 *** Locales ***
   952 
   953 * New commands for the interpretation of locale expressions in
   954 theories (1), locales (2) and proof contexts (3).  These generate
   955 proof obligations from the expression specification.  After the
   956 obligations have been discharged, theorems of the expression are added
   957 to the theory, target locale or proof context.  The synopsis of the
   958 commands is a follows:
   959 
   960   (1) interpretation expr inst
   961   (2) interpretation target < expr
   962   (3) interpret expr inst
   963 
   964 Interpretation in theories and proof contexts require a parameter
   965 instantiation of terms from the current context.  This is applied to
   966 specifications and theorems of the interpreted expression.
   967 Interpretation in locales only permits parameter renaming through the
   968 locale expression.  Interpretation is smart in that interpretations
   969 that are active already do not occur in proof obligations, neither are
   970 instantiated theorems stored in duplicate.  Use 'print_interps' to
   971 inspect active interpretations of a particular locale.  For details,
   972 see the Isar Reference manual.  Examples can be found in
   973 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
   974 
   975 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
   976 'interpret' instead.
   977 
   978 * New context element 'constrains' for adding type constraints to
   979 parameters.
   980 
   981 * Context expressions: renaming of parameters with syntax
   982 redeclaration.
   983 
   984 * Locale declaration: 'includes' disallowed.
   985 
   986 * Proper static binding of attribute syntax -- i.e. types / terms /
   987 facts mentioned as arguments are always those of the locale definition
   988 context, independently of the context of later invocations.  Moreover,
   989 locale operations (renaming and type / term instantiation) are applied
   990 to attribute arguments as expected.
   991 
   992 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
   993 actual attributes; rare situations may require Attrib.attribute to
   994 embed those attributes into Attrib.src that lack concrete syntax.
   995 Attribute implementations need to cooperate properly with the static
   996 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   997 Attrib.XXX_thm etc. already do the right thing without further
   998 intervention.  Only unusual applications -- such as "where" or "of"
   999 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1000 on the context and the facts involved -- may have to assign parsed
  1001 values to argument tokens explicitly.
  1002 
  1003 * Changed parameter management in theorem generation for long goal
  1004 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1005 theorem statement in rare situations.
  1006 
  1007 * Locale inspection command 'print_locale' omits notes elements.  Use
  1008 'print_locale!' to have them included in the output.
  1009 
  1010 
  1011 *** Provers ***
  1012 
  1013 * Provers/hypsubst.ML: improved version of the subst method, for
  1014 single-step rewriting: it now works in bound variable contexts. New is
  1015 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1016 rewrite a different subterm than the original subst method, which is
  1017 still available as 'simplesubst'.
  1018 
  1019 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1020 and quasi orders.
  1021 
  1022 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1023 reflexive-transitive closure of relations.
  1024 
  1025 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1026 limit (previously hard-coded with a value of 20) user-definable.
  1027 
  1028 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1029 is peformed already.  Object-logics merely need to finish their
  1030 initial simpset configuration as before.  INCOMPATIBILITY.
  1031 
  1032 
  1033 *** HOL ***
  1034 
  1035 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1036 
  1037   syntax (epsilon)
  1038     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1039 
  1040 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1041 and x-symbol; use option '-m epsilon' to get it actually printed.
  1042 Moreover, the mathematically important symbolic identifier \<epsilon>
  1043 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1044 
  1045 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1046 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1047 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1048 support corresponding Isar calculations.
  1049 
  1050 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1051 instead of ":".
  1052 
  1053 * theory SetInterval: changed the syntax for open intervals:
  1054 
  1055   Old       New
  1056   {..n(}    {..<n}
  1057   {)n..}    {n<..}
  1058   {m..n(}   {m..<n}
  1059   {)m..n}   {m<..n}
  1060   {)m..n(}  {m<..<n}
  1061 
  1062 The old syntax is still supported but will disappear in the next
  1063 release.  For conversion use the following Emacs search and replace
  1064 patterns (these are not perfect but work quite well):
  1065 
  1066   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1067   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1068 
  1069 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1070 equalities in commutative rings; method 'algebra' provides a generic
  1071 interface.
  1072 
  1073 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1074 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1075 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1076 be a tuple pattern.
  1077 
  1078 Some new syntax forms are available:
  1079 
  1080   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1081   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1082   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1083   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1084 
  1085 The latter form "\<Sum>x < k. e" used to be based on a separate
  1086 function "Summation", which has been discontinued.
  1087 
  1088 * theory Finite_Set: in structured induction proofs, the insert case
  1089 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1090 (insert F x)'.
  1091 
  1092 * The 'refute' command has been extended to support a much larger
  1093 fragment of HOL, including axiomatic type classes, constdefs and
  1094 typedefs, inductive datatypes and recursion.
  1095 
  1096 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1097 Requires zChaff with proof generation to be installed.  See
  1098 HOL/ex/SAT_Examples.thy for examples.
  1099 
  1100 * Datatype induction via method 'induct' now preserves the name of the
  1101 induction variable. For example, when proving P(xs::'a list) by
  1102 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1103 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1104 in unstructured proof scripts.
  1105 
  1106 * Reworked implementation of records.  Improved scalability for
  1107 records with many fields, avoiding performance problems for type
  1108 inference. Records are no longer composed of nested field types, but
  1109 of nested extension types. Therefore the record type only grows linear
  1110 in the number of extensions and not in the number of fields.  The
  1111 top-level (users) view on records is preserved.  Potential
  1112 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1113 old record representation. The type generated for a record is called
  1114 <record_name>_ext_type.
  1115 
  1116 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1117 proofs triggered by a record definition or a simproc (if
  1118 quick_and_dirty is enabled).  Definitions of large records can take
  1119 quite long.
  1120 
  1121 New simproc record_upd_simproc for simplification of multiple record
  1122 updates enabled by default.  Moreover, trivial updates are also
  1123 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1124 occasionally, since simplification is more powerful by default.
  1125 
  1126 * typedef: proper support for polymorphic sets, which contain extra
  1127 type-variables in the term.
  1128 
  1129 * Simplifier: automatically reasons about transitivity chains
  1130 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1131 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1132 old proofs break occasionally as simplification may now solve more
  1133 goals than previously.
  1134 
  1135 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1136 present.  Works for all partial orders (class "order"), in particular
  1137 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1138 just like y <= x.
  1139 
  1140 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1141 bound variable or a constant then the let is unfolded.  Otherwise
  1142 first a is simplified to b, and then f b is simplified to g. If
  1143 possible we abstract b from g arriving at "let x = b in h x",
  1144 otherwise we unfold the let and arrive at g.  The simproc can be
  1145 enabled/disabled by the reference use_let_simproc.  Potential
  1146 INCOMPATIBILITY since simplification is more powerful by default.
  1147 
  1148 * Classical reasoning: the meson method now accepts theorems as arguments.
  1149 
  1150 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1151 jobs to provide advice on the provability of subgoals.
  1152 
  1153 * Theory OrderedGroup and Ring_and_Field: various additions and
  1154 improvements to faciliate calculations involving equalities and
  1155 inequalities.
  1156 
  1157 The following theorems have been eliminated or modified
  1158 (INCOMPATIBILITY):
  1159 
  1160   abs_eq             now named abs_of_nonneg
  1161   abs_of_ge_0        now named abs_of_nonneg
  1162   abs_minus_eq       now named abs_of_nonpos
  1163   imp_abs_id         now named abs_of_nonneg
  1164   imp_abs_neg_id     now named abs_of_nonpos
  1165   mult_pos           now named mult_pos_pos
  1166   mult_pos_le        now named mult_nonneg_nonneg
  1167   mult_pos_neg_le    now named mult_nonneg_nonpos
  1168   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1169   mult_neg           now named mult_neg_neg
  1170   mult_neg_le        now named mult_nonpos_nonpos
  1171 
  1172 * Theory Parity: added rules for simplifying exponents.
  1173 
  1174 * Theory List:
  1175 
  1176 The following theorems have been eliminated or modified
  1177 (INCOMPATIBILITY):
  1178 
  1179   list_all_Nil       now named list_all.simps(1)
  1180   list_all_Cons      now named list_all.simps(2)
  1181   list_all_conv      now named list_all_iff
  1182   set_mem_eq         now named mem_iff
  1183 
  1184 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1185 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1186 
  1187 
  1188 *** HOL-Complex ***
  1189 
  1190 * Theory RealDef: better support for embedding natural numbers and
  1191 integers in the reals.
  1192 
  1193 The following theorems have been eliminated or modified
  1194 (INCOMPATIBILITY):
  1195 
  1196   exp_ge_add_one_self  now requires no hypotheses
  1197   real_of_int_add      reversed direction of equality (use [symmetric])
  1198   real_of_int_minus    reversed direction of equality (use [symmetric])
  1199   real_of_int_diff     reversed direction of equality (use [symmetric])
  1200   real_of_int_mult     reversed direction of equality (use [symmetric])
  1201 
  1202 * Theory RComplete: expanded support for floor and ceiling functions.
  1203 
  1204 * Theory Ln is new, with properties of the natural logarithm
  1205 
  1206 * Hyperreal: There is a new type constructor "star" for making
  1207 nonstandard types.  The old type names are now type synonyms:
  1208 
  1209   hypreal = real star
  1210   hypnat = nat star
  1211   hcomplex = complex star
  1212 
  1213 * Hyperreal: Many groups of similarly-defined constants have been
  1214 replaced by polymorphic versions (INCOMPATIBILITY):
  1215 
  1216   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1217 
  1218   starset      <-- starsetNat, starsetC
  1219   *s*          <-- *sNat*, *sc*
  1220   starset_n    <-- starsetNat_n, starsetC_n
  1221   *sn*         <-- *sNatn*, *scn*
  1222   InternalSets <-- InternalNatSets, InternalCSets
  1223 
  1224   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1225   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1226   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1227   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1228   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1229 
  1230 * Hyperreal: Many type-specific theorems have been removed in favor of
  1231 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1232 
  1233   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1234   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1235   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1236   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1237   right_minus <-- hypreal_add_minus
  1238   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1239   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1240   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1241   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1242   mult_1_right <-- hcomplex_mult_one_right
  1243   mult_zero_left <-- hcomplex_mult_zero_left
  1244   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1245   right_distrib <-- hypnat_add_mult_distrib2
  1246   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1247   right_inverse <-- hypreal_mult_inverse
  1248   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1249   order_refl <-- {hypreal,hypnat}_le_refl
  1250   order_trans <-- {hypreal,hypnat}_le_trans
  1251   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1252   order_less_le <-- {hypreal,hypnat}_less_le
  1253   linorder_linear <-- {hypreal,hypnat}_le_linear
  1254   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1255   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1256   add_nonneg_nonneg <-- hypreal_le_add_order
  1257 
  1258 * Hyperreal: Separate theorems having to do with type-specific
  1259 versions of constants have been merged into theorems that apply to the
  1260 new polymorphic constants (INCOMPATIBILITY):
  1261 
  1262   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1263   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1264   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1265   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1266   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1267   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1268   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1269   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1270   STAR_diff <-- {STAR,STARC}_diff
  1271   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1272     STARC_hcomplex_of_complex}_image_subset
  1273   starset_n_Un <-- starset{Nat,C}_n_Un
  1274   starset_n_Int <-- starset{Nat,C}_n_Int
  1275   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1276   starset_n_diff <-- starset{Nat,C}_n_diff
  1277   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1278   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1279   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1280   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1281   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1282   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1283   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1284   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1285   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1286   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1287   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1288   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1289   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1290   starfun_diff <-- starfun{C,RC,CR}_diff
  1291   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1292   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1293   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1294   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1295   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1296   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1297   starfun_Id <-- starfunC_Id
  1298   starfun_approx <-- starfun{Nat,CR}_approx
  1299   starfun_capprox <-- starfun{C,RC}_capprox
  1300   starfun_abs <-- starfunNat_rabs
  1301   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1302   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1303   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1304   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1305   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1306   starfun_add_approx <-- starfunCR_add_approx
  1307   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1308   starfun_divide <-- starfun{C,CR,RC}_divide
  1309   starfun_n <-- starfun{Nat,C}_n
  1310   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1311   starfun_n_add <-- starfun{Nat,C}_n_add
  1312   starfun_n_add_minus <-- starfunNat_n_add_minus
  1313   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1314   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1315   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1316 
  1317   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1318   star_n_minus <-- {hypreal,hcomplex}_minus
  1319   star_n_diff <-- {hypreal,hcomplex}_diff
  1320   star_n_mult <-- {hypreal,hcomplex}_mult
  1321   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1322   star_n_le <-- {hypreal,hypnat}_le
  1323   star_n_less <-- {hypreal,hypnat}_less
  1324   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1325   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1326   star_n_abs <-- hypreal_hrabs
  1327   star_n_divide <-- hcomplex_divide
  1328 
  1329   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1330   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1331   star_of_diff <-- hypreal_of_real_diff
  1332   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1333   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1334   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1335   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1336   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1337   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1338   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1339   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1340   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1341   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1342   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1343   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1344   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1345   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1346   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1347   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1348   star_of_power <-- hypreal_of_real_power
  1349   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1350 
  1351 * Hyperreal: new method "transfer" that implements the transfer
  1352 principle of nonstandard analysis. With a subgoal that mentions
  1353 nonstandard types like "'a star", the command "apply transfer"
  1354 replaces it with an equivalent one that mentions only standard types.
  1355 To be successful, all free variables must have standard types; non-
  1356 standard variables must have explicit universal quantifiers.
  1357 
  1358 * Hyperreal: A theory of Taylor series.
  1359 
  1360 
  1361 *** HOLCF ***
  1362 
  1363 * Discontinued special version of 'constdefs' (which used to support
  1364 continuous functions) in favor of the general Pure one with full
  1365 type-inference.
  1366 
  1367 * New simplification procedure for solving continuity conditions; it
  1368 is much faster on terms with many nested lambda abstractions (cubic
  1369 instead of exponential time).
  1370 
  1371 * New syntax for domain package: selector names are now optional.
  1372 Parentheses should be omitted unless argument is lazy, for example:
  1373 
  1374   domain 'a stream = cons "'a" (lazy "'a stream")
  1375 
  1376 * New command 'fixrec' for defining recursive functions with pattern
  1377 matching; defining multiple functions with mutual recursion is also
  1378 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1379 sinr, or any data constructor defined by the domain package. The given
  1380 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1381 syntax and examples.
  1382 
  1383 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1384 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1385 but the proof obligation additionally includes an admissibility
  1386 requirement. The packages generate instances of class cpo or pcpo,
  1387 with continuity and strictness theorems for Rep and Abs.
  1388 
  1389 * HOLCF: Many theorems have been renamed according to a more standard naming
  1390 scheme (INCOMPATIBILITY):
  1391 
  1392   foo_inject:  "foo$x = foo$y ==> x = y"
  1393   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1394   foo_less:    "(foo$x << foo$y) = (x << y)"
  1395   foo_strict:  "foo$UU = UU"
  1396   foo_defined: "... ==> foo$x ~= UU"
  1397   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1398 
  1399 
  1400 *** ZF ***
  1401 
  1402 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1403 including the First Isomorphism Theorem (on quotienting by the kernel
  1404 of a homomorphism).
  1405 
  1406 * ZF/Simplifier: install second copy of type solver that actually
  1407 makes use of TC rules declared to Isar proof contexts (or locales);
  1408 the old version is still required for ML proof scripts.
  1409 
  1410 
  1411 *** Cube ***
  1412 
  1413 * Converted to Isar theory format; use locales instead of axiomatic
  1414 theories.
  1415 
  1416 
  1417 *** ML ***
  1418 
  1419 * Pure/library.ML no longer defines its own option datatype, but uses
  1420 that of the SML basis, which has constructors NONE and SOME instead of
  1421 None and Some, as well as exception Option.Option instead of OPTION.
  1422 The functions the, if_none, is_some, is_none have been adapted
  1423 accordingly, while Option.map replaces apsome.
  1424 
  1425 * Pure/library.ML: the exception LIST has been given up in favour of
  1426 the standard exceptions Empty and Subscript, as well as
  1427 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1428 superceded by the standard hd and tl functions etc.
  1429 
  1430 A number of basic list functions are no longer exported to the ML
  1431 toplevel, as they are variants of predefined functions.  The following
  1432 suggests how one can translate existing code:
  1433 
  1434     rev_append xs ys = List.revAppend (xs, ys)
  1435     nth_elem (i, xs) = List.nth (xs, i)
  1436     last_elem xs = List.last xs
  1437     flat xss = List.concat xss
  1438     seq fs = List.app fs
  1439     partition P xs = List.partition P xs
  1440     mapfilter f xs = List.mapPartial f xs
  1441 
  1442 * Pure/library.ML: several combinators for linear functional
  1443 transformations, notably reverse application and composition:
  1444 
  1445   x |> f                f #> g
  1446   (x, y) |-> f          f #-> g
  1447 
  1448 * Pure/library.ML: introduced/changed precedence of infix operators:
  1449 
  1450   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1451   infix 2 ?;
  1452   infix 3 o oo ooo oooo;
  1453   infix 4 ~~ upto downto;
  1454 
  1455 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1456 infix operators.
  1457 
  1458 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1459 fold_map support linear functional transformations and nesting.  For
  1460 example:
  1461 
  1462   fold f [x1, ..., xN] y =
  1463     y |> f x1 |> ... |> f xN
  1464 
  1465   (fold o fold) f [xs1, ..., xsN] y =
  1466     y |> fold f xs1 |> ... |> fold f xsN
  1467 
  1468   fold f [x1, ..., xN] =
  1469     f x1 #> ... #> f xN
  1470 
  1471   (fold o fold) f [xs1, ..., xsN] =
  1472     fold f xs1 #> ... #> fold f xsN
  1473 
  1474 * Pure/library.ML: the following selectors on type 'a option are
  1475 available:
  1476 
  1477   the:               'a option -> 'a  (*partial*)
  1478   these:             'a option -> 'a  where 'a = 'b list
  1479   the_default: 'a -> 'a option -> 'a
  1480   the_list:          'a option -> 'a list
  1481 
  1482 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1483 basic operations for association lists, following natural argument
  1484 order; moreover the explicit equality predicate passed here avoids
  1485 potentially expensive polymorphic runtime equality checks.
  1486 The old functions may be expressed as follows:
  1487 
  1488   assoc = uncurry (AList.lookup (op =))
  1489   assocs = these oo AList.lookup (op =)
  1490   overwrite = uncurry (AList.update (op =)) o swap
  1491 
  1492 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1493 
  1494   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1495   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1496 
  1497 replacing make_keylist and keyfilter (occassionally used)
  1498 Naive rewrites:
  1499 
  1500   make_keylist = AList.make
  1501   keyfilter = AList.find (op =)
  1502 
  1503 * eq_fst and eq_snd now take explicit equality parameter, thus
  1504   avoiding eqtypes. Naive rewrites:
  1505 
  1506     eq_fst = eq_fst (op =)
  1507     eq_snd = eq_snd (op =)
  1508 
  1509 * Removed deprecated apl and apr (rarely used).
  1510   Naive rewrites:
  1511 
  1512     apl (n, op) =>>= curry op n
  1513     apr (op, m) =>>= fn n => op (n, m)
  1514 
  1515 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1516 provides a reasonably efficient light-weight implementation of sets as
  1517 lists.
  1518 
  1519 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1520 few new operations; existing lookup and update are now curried to
  1521 follow natural argument order (for use with fold etc.);
  1522 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1523 
  1524 * Pure/General: output via the Isabelle channels of
  1525 writeln/warning/error etc. is now passed through Output.output, with a
  1526 hook for arbitrary transformations depending on the print_mode
  1527 (cf. Output.add_mode -- the first active mode that provides a output
  1528 function wins).  Already formatted output may be embedded into further
  1529 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1530 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1531 accommodate easy composition of diagnostic messages etc.  Programmers
  1532 rarely need to care about Output.output or Output.raw at all, with
  1533 some notable exceptions: Output.output is required when bypassing the
  1534 standard channels (writeln etc.), or in token translations to produce
  1535 properly formatted results; Output.raw is required when capturing
  1536 already output material that will eventually be presented to the user
  1537 a second time.  For the default print mode, both Output.output and
  1538 Output.raw have no effect.
  1539 
  1540 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1541 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1542 cumulative results are displayed at the end of a batch session.
  1543 
  1544 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1545 replaced by File.platform_path and File.shell_path (with appropriate
  1546 hooks).  This provides a clean interface for unusual systems where the
  1547 internal and external process view of file names are different.
  1548 
  1549 * Pure: more efficient orders for basic syntactic entities: added
  1550 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1551 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1552 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1553 orders now -- potential INCOMPATIBILITY for code that depends on a
  1554 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1555 Library.sort_strings on result).
  1556 
  1557 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1558 fold_types traverse types/terms from left to right, observing natural
  1559 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1560 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1561 
  1562 * Pure: name spaces have been refined, with significant changes of the
  1563 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1564 to extern(_table).  The plain name entry path is superceded by a
  1565 general 'naming' context, which also includes the 'policy' to produce
  1566 a fully qualified name and external accesses of a fully qualified
  1567 name; NameSpace.extend is superceded by context dependent
  1568 Sign.declare_name.  Several theory and proof context operations modify
  1569 the naming context.  Especially note Theory.restore_naming and
  1570 ProofContext.restore_naming to get back to a sane state; note that
  1571 Theory.add_path is no longer sufficient to recover from
  1572 Theory.absolute_path in particular.
  1573 
  1574 * Pure: new flags short_names (default false) and unique_names
  1575 (default true) for controlling output of qualified names.  If
  1576 short_names is set, names are printed unqualified.  If unique_names is
  1577 reset, the name prefix is reduced to the minimum required to achieve
  1578 the original result when interning again, even if there is an overlap
  1579 with earlier declarations.
  1580 
  1581 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1582 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1583 (useful for printing error messages).  INCOMPATIBILITY.
  1584 
  1585 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1586 Theory.theory are now identified, referring to the universal
  1587 Context.theory (see Pure/context.ML).  Actual signature and theory
  1588 content is managed as theory data.  The old code and interfaces were
  1589 spread over many files and structures; the new arrangement introduces
  1590 considerable INCOMPATIBILITY to gain more clarity:
  1591 
  1592   Context -- theory management operations (name, identity, inclusion,
  1593     parents, ancestors, merge, etc.), plus generic theory data;
  1594 
  1595   Sign -- logical signature and syntax operations (declaring consts,
  1596     types, etc.), plus certify/read for common entities;
  1597 
  1598   Theory -- logical theory operations (stating axioms, definitions,
  1599     oracles), plus a copy of logical signature operations (consts,
  1600     types, etc.); also a few basic management operations (Theory.copy,
  1601     Theory.merge, etc.)
  1602 
  1603 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  1604 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  1605 for convenience -- they merely return the theory.
  1606 
  1607 * Pure: type Type.tsig is superceded by theory in most interfaces.
  1608 
  1609 * Pure: the Isar proof context type is already defined early in Pure
  1610 as Context.proof (note that ProofContext.context and Proof.context are
  1611 aliases, where the latter is the preferred name).  This enables other
  1612 Isabelle components to refer to that type even before Isar is present.
  1613 
  1614 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  1615 typeK, constK, axiomK, oracleK), but provide explicit operations for
  1616 any of these kinds.  For example, Sign.intern typeK is now
  1617 Sign.intern_type, Theory.hide_space Sign.typeK is now
  1618 Theory.hide_types.  Also note that former
  1619 Theory.hide_classes/types/consts are now
  1620 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  1621 internalize their arguments!  INCOMPATIBILITY.
  1622 
  1623 * Pure: get_thm interface (of PureThy and ProofContext) expects
  1624 datatype thmref (with constructors Name and NameSelection) instead of
  1625 plain string -- INCOMPATIBILITY;
  1626 
  1627 * Pure: cases produced by proof methods specify options, where NONE
  1628 means to remove case bindings -- INCOMPATIBILITY in
  1629 (RAW_)METHOD_CASES.
  1630 
  1631 * Pure: the following operations retrieve axioms or theorems from a
  1632 theory node or theory hierarchy, respectively:
  1633 
  1634   Theory.axioms_of: theory -> (string * term) list
  1635   Theory.all_axioms_of: theory -> (string * term) list
  1636   PureThy.thms_of: theory -> (string * thm) list
  1637   PureThy.all_thms_of: theory -> (string * thm) list
  1638 
  1639 * Pure: print_tac now outputs the goal through the trace channel.
  1640 
  1641 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  1642 Reference Toplevel.debug (default false) controls detailed printing
  1643 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  1644 controls execution profiling -- set to 1 for time and 2 for space
  1645 (both increase the runtime).
  1646 
  1647 * Isar session: The initial use of ROOT.ML is now always timed,
  1648 i.e. the log will show the actual process times, in contrast to the
  1649 elapsed wall-clock time that the outer shell wrapper produces.
  1650 
  1651 * Simplifier: improved handling of bound variables (nameless
  1652 representation, avoid allocating new strings).  Simprocs that invoke
  1653 the Simplifier recursively should use Simplifier.inherit_bounds to
  1654 avoid local name clashes.  Failure to do so produces warnings
  1655 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  1656 for further details.
  1657 
  1658 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  1659 bindings for all theorems stored within a given theory; this may help
  1660 in porting non-Isar theories to Isar ones, while keeping ML proof
  1661 scripts for the time being.
  1662 
  1663 * ML operator HTML.with_charset specifies the charset begin used for
  1664 generated HTML files.  For example:
  1665 
  1666   HTML.with_charset "utf-8" use_thy "Hebrew";
  1667   HTML.with_charset "utf-8" use_thy "Chinese";
  1668 
  1669 
  1670 *** System ***
  1671 
  1672 * Allow symlinks to all proper Isabelle executables (Isabelle,
  1673 isabelle, isatool etc.).
  1674 
  1675 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  1676 isatool doc, isatool mkdir, display_drafts etc.).
  1677 
  1678 * isatool usedir: option -f allows specification of the ML file to be
  1679 used by Isabelle; default is ROOT.ML.
  1680 
  1681 * New isatool version outputs the version identifier of the Isabelle
  1682 distribution being used.
  1683 
  1684 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1685 (containing Boolean satisfiability problems) into Isabelle/HOL
  1686 theories.
  1687 
  1688 
  1689 
  1690 New in Isabelle2004 (April 2004)
  1691 --------------------------------
  1692 
  1693 *** General ***
  1694 
  1695 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1696   Replaces linorder.ML.
  1697 
  1698 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1699   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1700   (\<a>...\<z>), are now considered normal letters, and can therefore
  1701   be used anywhere where an ASCII letter (a...zA...Z) has until
  1702   now. COMPATIBILITY: This obviously changes the parsing of some
  1703   terms, especially where a symbol has been used as a binder, say
  1704   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1705   as an identifier.  Fix it by inserting a space around former
  1706   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1707   existing theory and ML files.
  1708 
  1709 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  1710 
  1711 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  1712   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  1713   a normal (but invisible) letter. For multiple letter subscripts repeat
  1714   \<^isub> like this: x\<^isub>1\<^isub>2.
  1715 
  1716 * Pure: There are now sub-/superscripts that can span more than one
  1717   character. Text between \<^bsub> and \<^esub> is set in subscript in
  1718   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  1719   superscript. The new control characters are not identifier parts.
  1720 
  1721 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  1722   content of "..." to the latex file instead of \isacntrl... . The "..."
  1723   may consist of any printable characters excluding the end bracket >.
  1724 
  1725 * Pure: Using new Isar command "finalconsts" (or the ML functions
  1726   Theory.add_finals or Theory.add_finals_i) it is now possible to
  1727   declare constants "final", which prevents their being given a definition
  1728   later.  It is useful for constants whose behaviour is fixed axiomatically
  1729   rather than definitionally, such as the meta-logic connectives.
  1730 
  1731 * Pure: 'instance' now handles general arities with general sorts
  1732   (i.e. intersections of classes),
  1733 
  1734 * Presentation: generated HTML now uses a CSS style sheet to make layout
  1735   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  1736   It can be changed to alter the colors/layout of generated pages.
  1737 
  1738 
  1739 *** Isar ***
  1740 
  1741 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  1742   cut_tac, subgoal_tac and thin_tac:
  1743   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  1744     locales are no longer forced to write Isar proof scripts.
  1745     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  1746     emulations.
  1747   - INCOMPATIBILITY: names of variables to be instantiated may no
  1748     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  1749     This is consistent with the instantiation attribute "where".
  1750 
  1751 * Attributes "where" and "of":
  1752   - Now take type variables of instantiated theorem into account when reading
  1753     the instantiation string.  This fixes a bug that caused instantiated
  1754     theorems to have too special types in some circumstances.
  1755   - "where" permits explicit instantiations of type variables.
  1756 
  1757 * Calculation commands "moreover" and "also" no longer interfere with
  1758   current facts ("this"), admitting arbitrary combinations with "then"
  1759   and derived forms.
  1760 
  1761 * Locales:
  1762   - Goal statements involving the context element "includes" no longer
  1763     generate theorems with internal delta predicates (those ending on
  1764     "_axioms") in the premise.
  1765     Resolve particular premise with <locale>.intro to obtain old form.
  1766   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  1767     specification and "includes" elements in goal statement.
  1768   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  1769     [intro?] and [elim?] (respectively) by default.
  1770   - Experimental command for instantiation of locales in proof contexts:
  1771         instantiate <label>[<attrs>]: <loc>
  1772     Instantiates locale <loc> and adds all its theorems to the current context
  1773     taking into account their attributes.  Label and attrs are optional
  1774     modifiers, like in theorem declarations.  If present, names of
  1775     instantiated theorems are qualified with <label>, and the attributes
  1776     <attrs> are applied after any attributes these theorems might have already.
  1777       If the locale has assumptions, a chained fact of the form
  1778     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  1779     are derived.  The command does not support old-style locales declared
  1780     with "locale (open)".
  1781       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  1782 
  1783 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  1784   (Isar) contexts.
  1785 
  1786 
  1787 *** HOL ***
  1788 
  1789 * Proof import: new image HOL4 contains the imported library from
  1790   the HOL4 system with about 2500 theorems. It is imported by
  1791   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  1792   can be used like any other Isabelle image.  See
  1793   HOL/Import/HOL/README for more information.
  1794 
  1795 * Simplifier:
  1796   - Much improved handling of linear and partial orders.
  1797     Reasoners for linear and partial orders are set up for type classes
  1798     "linorder" and "order" respectively, and are added to the default simpset
  1799     as solvers.  This means that the simplifier can build transitivity chains
  1800     to solve goals from the assumptions.
  1801   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  1802     of blast or auto after simplification become unnecessary because the goal
  1803     is solved by simplification already.
  1804 
  1805 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  1806     all proved in axiomatic type classes for semirings, rings and fields.
  1807 
  1808 * Numerics:
  1809   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  1810     now formalized using the Ring_and_Field theory mentioned above.
  1811   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  1812     than before, because now they are set up once in a generic manner.
  1813   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  1814     Look for the general versions in Ring_and_Field (and Power if they concern
  1815     exponentiation).
  1816 
  1817 * Type "rat" of the rational numbers is now available in HOL-Complex.
  1818 
  1819 * Records:
  1820   - Record types are now by default printed with their type abbreviation
  1821     instead of the list of all field types. This can be configured via
  1822     the reference "print_record_type_abbr".
  1823   - Simproc "record_upd_simproc" for simplification of multiple updates added
  1824     (not enabled by default).
  1825   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  1826     EX x. x = sel r to True (not enabled by default).
  1827   - Tactic "record_split_simp_tac" to split and simplify records added.
  1828 
  1829 * 'specification' command added, allowing for definition by
  1830   specification.  There is also an 'ax_specification' command that
  1831   introduces the new constants axiomatically.
  1832 
  1833 * arith(_tac) is now able to generate counterexamples for reals as well.
  1834 
  1835 * HOL-Algebra: new locale "ring" for non-commutative rings.
  1836 
  1837 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  1838   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  1839 
  1840 * HOL-Matrix: a first theory for matrices in HOL with an application of
  1841   matrix theory to linear programming.
  1842 
  1843 * Unions and Intersections:
  1844   The latex output syntax of UN and INT has been changed
  1845   from "\Union x \in A. B" to "\Union_{x \in A} B"
  1846   i.e. the index formulae has become a subscript.
  1847   Similarly for "\Union x. B", and for \Inter instead of \Union.
  1848 
  1849 * Unions and Intersections over Intervals:
  1850   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  1851   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  1852   like in normal math, and corresponding versions for < and for intersection.
  1853 
  1854 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  1855   lexicographic dictonary ordering has been added as "lexord".
  1856 
  1857 * ML: the legacy theory structures Int and List have been removed. They had
  1858   conflicted with ML Basis Library structures having the same names.
  1859 
  1860 * 'refute' command added to search for (finite) countermodels.  Only works
  1861   for a fragment of HOL.  The installation of an external SAT solver is
  1862   highly recommended.  See "HOL/Refute.thy" for details.
  1863 
  1864 * 'quickcheck' command: Allows to find counterexamples by evaluating
  1865   formulae under an assignment of free variables to random values.
  1866   In contrast to 'refute', it can deal with inductive datatypes,
  1867   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  1868   for examples.
  1869 
  1870 
  1871 *** HOLCF ***
  1872 
  1873 * Streams now come with concatenation and are part of the HOLCF image
  1874 
  1875 
  1876 
  1877 New in Isabelle2003 (May 2003)
  1878 ------------------------------
  1879 
  1880 *** General ***
  1881 
  1882 * Provers/simplifier:
  1883 
  1884   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  1885     Assumptions are now subject to complete mutual simplification,
  1886     not just from left to right. The simplifier now preserves
  1887     the order of assumptions.
  1888 
  1889     Potential INCOMPATIBILITY:
  1890 
  1891     -- simp sometimes diverges where the old version did
  1892        not, e.g. invoking simp on the goal
  1893 
  1894         [| P (f x); y = x; f x = f y |] ==> Q
  1895 
  1896        now gives rise to the infinite reduction sequence
  1897 
  1898         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  1899 
  1900        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  1901        kind of problem.
  1902 
  1903     -- Tactics combining classical reasoner and simplification (such as auto)
  1904        are also affected by this change, because many of them rely on
  1905        simp. They may sometimes diverge as well or yield a different numbers
  1906        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  1907        in case of problems. Sometimes subsequent calls to the classical
  1908        reasoner will fail because a preceeding call to the simplifier too
  1909        eagerly simplified the goal, e.g. deleted redundant premises.
  1910 
  1911   - The simplifier trace now shows the names of the applied rewrite rules
  1912 
  1913   - You can limit the number of recursive invocations of the simplifier
  1914     during conditional rewriting (where the simplifie tries to solve the
  1915     conditions before applying the rewrite rule):
  1916     ML "simp_depth_limit := n"
  1917     where n is an integer. Thus you can force termination where previously
  1918     the simplifier would diverge.
  1919 
  1920   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  1921 
  1922   - No longer aborts on failed congruence proof.  Instead, the
  1923     congruence is ignored.
  1924 
  1925 * Pure: New generic framework for extracting programs from constructive
  1926   proofs. See HOL/Extraction.thy for an example instantiation, as well
  1927   as HOL/Extraction for some case studies.
  1928 
  1929 * Pure: The main goal of the proof state is no longer shown by default, only
  1930 the subgoals. This behaviour is controlled by a new flag.
  1931    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  1932 (ML: Proof.show_main_goal).
  1933 
  1934 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  1935 rules whose conclusion matches subgoal 1:
  1936       PG menu: Isabelle/Isar -> Show me -> matching rules
  1937 The rules are ordered by how closely they match the subgoal.
  1938 In particular, rules that solve a subgoal outright are displayed first
  1939 (or rather last, the way they are printed).
  1940 (ML: ProofGeneral.print_intros())
  1941 
  1942 * Pure: New flag trace_unify_fail causes unification to print
  1943 diagnostic information (PG: in trace buffer) when it fails. This is
  1944 useful for figuring out why single step proofs like rule, erule or
  1945 assumption failed.
  1946 
  1947 * Pure: Locale specifications now produce predicate definitions
  1948 according to the body of text (covering assumptions modulo local
  1949 definitions); predicate "loc_axioms" covers newly introduced text,
  1950 while "loc" is cumulative wrt. all included locale expressions; the
  1951 latter view is presented only on export into the global theory
  1952 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  1953 on the old view without predicates;
  1954 
  1955 * Pure: predefined locales "var" and "struct" are useful for sharing
  1956 parameters (as in CASL, for example); just specify something like
  1957 ``var x + var y + struct M'' as import;
  1958 
  1959 * Pure: improved thms_containing: proper indexing of facts instead of
  1960 raw theorems; check validity of results wrt. current name space;
  1961 include local facts of proof configuration (also covers active
  1962 locales), cover fixed variables in index; may use "_" in term
  1963 specification; an optional limit for the number of printed facts may
  1964 be given (the default is 40);
  1965 
  1966 * Pure: disallow duplicate fact bindings within new-style theory files
  1967 (batch-mode only);
  1968 
  1969 * Provers: improved induct method: assumptions introduced by case
  1970 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  1971 the goal statement); "foo" still refers to all facts collectively;
  1972 
  1973 * Provers: the function blast.overloaded has been removed: all constants
  1974 are regarded as potentially overloaded, which improves robustness in exchange
  1975 for slight decrease in efficiency;
  1976 
  1977 * Provers/linorder: New generic prover for transitivity reasoning over
  1978 linear orders.  Note: this prover is not efficient!
  1979 
  1980 * Isar: preview of problems to finish 'show' now produce an error
  1981 rather than just a warning (in interactive mode);
  1982 
  1983 
  1984 *** HOL ***
  1985 
  1986 * arith(_tac)
  1987 
  1988  - Produces a counter example if it cannot prove a goal.
  1989    Note that the counter example may be spurious if the goal is not a formula
  1990    of quantifier-free linear arithmetic.
  1991    In ProofGeneral the counter example appears in the trace buffer.
  1992 
  1993  - Knows about div k and mod k where k is a numeral of type nat or int.
  1994 
  1995  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  1996    linear arithmetic fails. This takes account of quantifiers and divisibility.
  1997    Presburger arithmetic can also be called explicitly via presburger(_tac).
  1998 
  1999 * simp's arithmetic capabilities have been enhanced a bit: it now
  2000 takes ~= in premises into account (by performing a case split);
  2001 
  2002 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2003 are distributed over a sum of terms;
  2004 
  2005 * New tactic "trans_tac" and method "trans" instantiate
  2006 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2007 "<=", "<" and "=").
  2008 
  2009 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2010 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2011 
  2012 * 'typedef' command has new option "open" to suppress the set
  2013 definition;
  2014 
  2015 * functions Min and Max on finite sets have been introduced (theory
  2016 Finite_Set);
  2017 
  2018 * attribute [symmetric] now works for relations as well; it turns
  2019 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2020 
  2021 * induct over a !!-quantified statement (say !!x1..xn):
  2022   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2023 
  2024 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2025 %x. None. Warning: empty_def now refers to the previously hidden definition
  2026 of the empty set.
  2027 
  2028 * Algebra: formalization of classical algebra.  Intended as base for
  2029 any algebraic development in Isabelle.  Currently covers group theory
  2030 (up to Sylow's theorem) and ring theory (Universal Property of
  2031 Univariate Polynomials).  Contributions welcome;
  2032 
  2033 * GroupTheory: deleted, since its material has been moved to Algebra;
  2034 
  2035 * Complex: new directory of the complex numbers with numeric constants,
  2036 nonstandard complex numbers, and some complex analysis, standard and
  2037 nonstandard (Jacques Fleuriot);
  2038 
  2039 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2040 
  2041 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2042 Fleuriot);
  2043 
  2044 * Real/HahnBanach: updated and adapted to locales;
  2045 
  2046 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2047 Gray and Kramer);
  2048 
  2049 * UNITY: added the Meier-Sanders theory of progress sets;
  2050 
  2051 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2052 as abstract algorithms, instantiated to the JVM;
  2053 
  2054 * Bali: Java source language formalization. Type system, operational
  2055 semantics, axiomatic semantics. Supported language features:
  2056 classes, interfaces, objects,virtual methods, static methods,
  2057 static/instance fields, arrays, access modifiers, definite
  2058 assignment, exceptions.
  2059 
  2060 
  2061 *** ZF ***
  2062 
  2063 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2064 universe, etc.);
  2065 
  2066 * Main ZF: virtually all theories converted to new-style format;
  2067 
  2068 
  2069 *** ML ***
  2070 
  2071 * Pure: Tactic.prove provides sane interface for internal proofs;
  2072 omits the infamous "standard" operation, so this is more appropriate
  2073 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2074 
  2075 * Pure: improved error reporting of simprocs;
  2076 
  2077 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2078 up simprocs;
  2079 
  2080 
  2081 *** Document preparation ***
  2082 
  2083 * uses \par instead of \\ for line breaks in theory text. This may
  2084 shift some page breaks in large documents. To get the old behaviour
  2085 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2086 
  2087 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2088 other packages
  2089 
  2090 * \<euro> now needs package babel/greek instead of marvosym (which
  2091 broke \Rightarrow)
  2092 
  2093 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2094 textcomp package)
  2095 
  2096 
  2097 
  2098 New in Isabelle2002 (March 2002)
  2099 --------------------------------
  2100 
  2101 *** Document preparation ***
  2102 
  2103 * greatly simplified document preparation setup, including more
  2104 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2105 instructive isatool mkdir; users should basically be able to get
  2106 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2107 users may run a separate document processing stage manually like this:
  2108 "isatool usedir -D output HOL Test && isatool document Test/output";
  2109 
  2110 * theory dependency graph may now be incorporated into documents;
  2111 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2112 with \includegraphics of LaTeX;
  2113 
  2114 * proper spacing of consecutive markup elements, especially text
  2115 blocks after section headings;
  2116 
  2117 * support bold style (for single symbols only), input syntax is like
  2118 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2119 
  2120 * \<bullet> is now output as bold \cdot by default, which looks much
  2121 better in printed text;
  2122 
  2123 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2124 note that these symbols are currently unavailable in Proof General /
  2125 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2126 
  2127 * isatool latex no longer depends on changed TEXINPUTS, instead
  2128 isatool document copies the Isabelle style files to the target
  2129 location;
  2130 
  2131 
  2132 *** Isar ***
  2133 
  2134 * Pure/Provers: improved proof by cases and induction;
  2135   - 'case' command admits impromptu naming of parameters (such as
  2136     "case (Suc n)");
  2137   - 'induct' method divinates rule instantiation from the inductive
  2138     claim; no longer requires excessive ?P bindings for proper
  2139     instantiation of cases;
  2140   - 'induct' method properly enumerates all possibilities of set/type
  2141     rules; as a consequence facts may be also passed through *type*
  2142     rules without further ado;
  2143   - 'induct' method now derives symbolic cases from the *rulified*
  2144     rule (before it used to rulify cases stemming from the internal
  2145     atomized version); this means that the context of a non-atomic
  2146     statement becomes is included in the hypothesis, avoiding the
  2147     slightly cumbersome show "PROP ?case" form;
  2148   - 'induct' may now use elim-style induction rules without chaining
  2149     facts, using ``missing'' premises from the goal state; this allows
  2150     rules stemming from inductive sets to be applied in unstructured
  2151     scripts, while still benefitting from proper handling of non-atomic
  2152     statements; NB: major inductive premises need to be put first, all
  2153     the rest of the goal is passed through the induction;
  2154   - 'induct' proper support for mutual induction involving non-atomic
  2155     rule statements (uses the new concept of simultaneous goals, see
  2156     below);
  2157   - append all possible rule selections, but only use the first
  2158     success (no backtracking);
  2159   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2160   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2161   - added 'print_induct_rules' (covered by help item in recent Proof
  2162     General versions);
  2163   - moved induct/cases attributes to Pure, methods to Provers;
  2164   - generic method setup instantiated for FOL and HOL;
  2165 
  2166 * Pure: support multiple simultaneous goal statements, for example
  2167 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2168 meta-level mechanism, this acts as if several individual goals had
  2169 been stated separately; in particular common proof methods need to be
  2170 repeated in order to cover all claims; note that a single elimination
  2171 step is *not* sufficient to establish the two conjunctions, so this
  2172 fails:
  2173 
  2174   assume "A & B" then have A and B ..   (*".." fails*)
  2175 
  2176 better use "obtain" in situations as above; alternative refer to
  2177 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2178 
  2179 * Pure: proper integration with ``locales''; unlike the original
  2180 version by Florian Kammller, Isar locales package high-level proof
  2181 contexts rather than raw logical ones (e.g. we admit to include
  2182 attributes everywhere); operations on locales include merge and
  2183 rename; support for implicit arguments (``structures''); simultaneous
  2184 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2185 some examples;
  2186 
  2187 * Pure: the following commands have been ``localized'', supporting a
  2188 target locale specification "(in name)": 'lemma', 'theorem',
  2189 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2190 stored both within the locale and at the theory level (exported and
  2191 qualified by the locale name);
  2192 
  2193 * Pure: theory goals may now be specified in ``long'' form, with
  2194 ad-hoc contexts consisting of arbitrary locale elements. for example
  2195 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2196 definitions may be given, too); the result is a meta-level rule with
  2197 the context elements being discharged in the obvious way;
  2198 
  2199 * Pure: new proof command 'using' allows to augment currently used
  2200 facts after a goal statement ('using' is syntactically analogous to
  2201 'apply', but acts on the goal's facts only); this allows chained facts
  2202 to be separated into parts given before and after a claim, as in
  2203 ``from a and b have C using d and e <proof>'';
  2204 
  2205 * Pure: renamed "antecedent" case to "rule_context";
  2206 
  2207 * Pure: new 'judgment' command records explicit information about the
  2208 object-logic embedding (used by several tools internally); no longer
  2209 use hard-wired "Trueprop";
  2210 
  2211 * Pure: added 'corollary' command;
  2212 
  2213 * Pure: fixed 'token_translation' command;
  2214 
  2215 * Pure: removed obsolete 'exported' attribute;
  2216 
  2217 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2218 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2219 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2220 
  2221 * Pure: method 'atomize' presents local goal premises as object-level
  2222 statements (atomic meta-level propositions); setup controlled via
  2223 rewrite rules declarations of 'atomize' attribute; example
  2224 application: 'induct' method with proper rule statements in improper
  2225 proof *scripts*;
  2226 
  2227 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2228 now consider the syntactic context of assumptions, giving a better
  2229 chance to get type-inference of the arguments right (this is
  2230 especially important for locales);
  2231 
  2232 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2233 mode;
  2234 
  2235 * Pure/obtain: the formal conclusion "thesis", being marked as
  2236 ``internal'', may no longer be reference directly in the text;
  2237 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2238 situations;
  2239 
  2240 * Pure: generic 'sym' attribute which declares a rule both as pure
  2241 'elim?' and for the 'symmetric' operation;
  2242 
  2243 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2244 text; the fixed correlation with particular command syntax has been
  2245 discontinued;
  2246 
  2247 * Pure: new method 'rules' is particularly well-suited for proof
  2248 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2249 but often produces more compact proof terms with less detours;
  2250 
  2251 * Pure/Provers/classical: simplified integration with pure rule
  2252 attributes and methods; the classical "intro?/elim?/dest?"
  2253 declarations coincide with the pure ones; the "rule" method no longer
  2254 includes classically swapped intros; "intro" and "elim" methods no
  2255 longer pick rules from the context; also got rid of ML declarations
  2256 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2257 INCOMPATIBILITY;
  2258 
  2259 * Provers/classical: attribute 'swapped' produces classical inversions
  2260 of introduction rules;
  2261 
  2262 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2263 rules instead of full simplifier context; 'iff' attribute handles
  2264 conditional rules;
  2265 
  2266 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2267 
  2268 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2269 "(permissive)" option to recover old behavior;
  2270 
  2271 * HOL: 'inductive' no longer features separate (collective) attributes
  2272 for 'intros' (was found too confusing);
  2273 
  2274 * HOL: properly declared induction rules less_induct and
  2275 wf_induct_rule;
  2276 
  2277 
  2278 *** HOL ***
  2279 
  2280 * HOL: moved over to sane numeral syntax; the new policy is as
  2281 follows:
  2282 
  2283   - 0 and 1 are polymorphic constants, which are defined on any
  2284   numeric type (nat, int, real etc.);
  2285 
  2286   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2287   binary representation internally;
  2288 
  2289   - type nat has special constructor Suc, and generally prefers Suc 0
  2290   over 1::nat and Suc (Suc 0) over 2::nat;
  2291 
  2292 This change may cause significant problems of INCOMPATIBILITY; here
  2293 are some hints on converting existing sources:
  2294 
  2295   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2296   entities, so expressions involving "-" (unary or binary minus) need
  2297   to be spaced properly;
  2298 
  2299   - existing occurrences of "1" may need to be constraint "1::nat" or
  2300   even replaced by Suc 0; similar for old "2";
  2301 
  2302   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2303 
  2304   - remove all special provisions on numerals in proofs;
  2305 
  2306 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2307 representation (depends on bin_arith_simps in the default context);
  2308 
  2309 * HOL: symbolic syntax for x^2 (numeral 2);
  2310 
  2311 * HOL: the class of all HOL types is now called "type" rather than
  2312 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2313 in axclass/classes, instance/arities, and (usually rare) occurrences
  2314 in typings (of consts etc.); internally the class is called
  2315 "HOL.type", ML programs should refer to HOLogic.typeS;
  2316 
  2317 * HOL/record package improvements:
  2318   - new derived operations "fields" to build a partial record section,
  2319     "extend" to promote a fixed record to a record scheme, and
  2320     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2321     declared as simp by default;
  2322   - shared operations ("more", "fields", etc.) now need to be always
  2323     qualified) --- potential INCOMPATIBILITY;
  2324   - removed "make_scheme" operations (use "make" with "extend") --
  2325     INCOMPATIBILITY;
  2326   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2327   - provides cases/induct rules for use with corresponding Isar
  2328     methods (for concrete records, record schemes, concrete more
  2329     parts, and schematic more parts -- in that order);
  2330   - internal definitions directly based on a light-weight abstract
  2331     theory of product types over typedef rather than datatype;
  2332 
  2333 * HOL: generic code generator for generating executable ML code from
  2334 specifications; specific support for HOL constructs such as inductive
  2335 datatypes and sets, as well as recursive functions; can be invoked
  2336 via 'generate_code' theory section;
  2337 
  2338 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2339 
  2340 * HOL: consolidated and renamed several theories.  In particular:
  2341         Ord.thy has been absorbed into HOL.thy
  2342         String.thy has been absorbed into List.thy
  2343 
  2344 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2345 (beware of argument permutation!);
  2346 
  2347 * HOL: linorder_less_split superseded by linorder_cases;
  2348 
  2349 * HOL/List: "nodups" renamed to "distinct";
  2350 
  2351 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2352 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2353   - Ex_def has changed, now need to use some_eq_ex
  2354 
  2355 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2356 in this (rare) case use:
  2357 
  2358   delSWrapper "split_all_tac"
  2359   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2360 
  2361 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2362 MAY FAIL;
  2363 
  2364 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2365 Isabelle's type classes, ^ on functions and relations has too general
  2366 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2367 necessary to attach explicit type constraints;
  2368 
  2369 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2370 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2371 renamed accordingly (eg "compI" -> "rel_compI").
  2372 
  2373 * HOL: syntax translations now work properly with numerals and records
  2374 expressions;
  2375 
  2376 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2377 of "lam" -- INCOMPATIBILITY;
  2378 
  2379 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2380 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2381 renamed "Product_Type.unit";
  2382 
  2383 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2384 
  2385 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2386 the "cases" method);
  2387 
  2388 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2389 Florian Kammller);
  2390 
  2391 * HOL/IMP: updated and converted to new-style theory format; several
  2392 parts turned into readable document, with proper Isar proof texts and
  2393 some explanations (by Gerwin Klein);
  2394 
  2395 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2396 
  2397 * HOL-Hyperreal is now a logic image;
  2398 
  2399 
  2400 *** HOLCF ***
  2401 
  2402 * Isar: consts/constdefs supports mixfix syntax for continuous
  2403 operations;
  2404 
  2405 * Isar: domain package adapted to new-style theory format, e.g. see
  2406 HOLCF/ex/Dnat.thy;
  2407 
  2408 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2409 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2410 lift.induct_tac, always use UU instead of Undef;
  2411 
  2412 * HOLCF/IMP: updated and converted to new-style theory;
  2413 
  2414 
  2415 *** ZF ***
  2416 
  2417 * Isar: proper integration of logic-specific tools and packages,
  2418 including theory commands '(co)inductive', '(co)datatype',
  2419 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2420 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2421 
  2422 * theory Main no longer includes AC; for the Axiom of Choice, base
  2423 your theory on Main_ZFC;
  2424 
  2425 * the integer library now covers quotients and remainders, with many
  2426 laws relating division to addition, multiplication, etc.;
  2427 
  2428 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2429 typeless version of the formalism;
  2430 
  2431 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2432 format;
  2433 
  2434 * ZF/Induct: new directory for examples of inductive definitions,
  2435 including theory Multiset for multiset orderings; converted to
  2436 new-style theory format;
  2437 
  2438 * ZF: many new theorems about lists, ordinals, etc.;
  2439 
  2440 
  2441 *** General ***
  2442 
  2443 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2444 variable proof controls level of detail: 0 = no proofs (only oracle
  2445 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2446 also ref manual for further ML interfaces;
  2447 
  2448 * Pure/axclass: removed obsolete ML interface
  2449 goal_subclass/goal_arity;
  2450 
  2451 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2452 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2453 separate tokens, so expressions involving minus need to be spaced
  2454 properly;
  2455 
  2456 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2457 rather than "infixl" or "infixr";
  2458 
  2459 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2460 sort constraint specifications in type inference; e.g. "x::_::foo"
  2461 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2462 type variable);
  2463 
  2464 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2465 control output of nested => (types); the default behavior is
  2466 "type_brackets";
  2467 
  2468 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2469 tokens into AST constants;
  2470 
  2471 * Pure/syntax: prefer later declarations of translations and print
  2472 translation functions; potential INCOMPATIBILITY: need to reverse
  2473 multiple declarations for same syntax element constant;
  2474 
  2475 * Pure/show_hyps reset by default (in accordance to existing Isar
  2476 practice);
  2477 
  2478 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2479 addSafter;
  2480 
  2481 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2482 as well;
  2483 
  2484 * system: tested support for MacOS X; should be able to get Isabelle +
  2485 Proof General to work in a plain Terminal after installing Poly/ML
  2486 (e.g. from the Isabelle distribution area) and GNU bash alone
  2487 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2488 support requires further installations, e.g. from
  2489 http://fink.sourceforge.net/);
  2490 
  2491 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2492 
  2493 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2494 of 40 MB), cf. ML_OPTIONS;
  2495 
  2496 * system: Proof General keywords specification is now part of the
  2497 Isabelle distribution (see etc/isar-keywords.el);
  2498 
  2499 * system: support for persistent Proof General sessions (refrain from
  2500 outdating all loaded theories on startup); user may create writable
  2501 logic images like this: ``isabelle -q HOL Test'';
  2502 
  2503 * system: smart selection of Isabelle process versus Isabelle
  2504 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2505 run both "isabelle" and "Isabelle" even if file names are badly
  2506 damaged (executable inspects the case of the first letter of its own
  2507 name); added separate "isabelle-process" and "isabelle-interface";
  2508 
  2509 * system: refrain from any attempt at filtering input streams; no
  2510 longer support ``8bit'' encoding of old isabelle font, instead proper
  2511 iso-latin characters may now be used; the related isatools
  2512 "symbolinput" and "nonascii" have disappeared as well;
  2513 
  2514 * system: removed old "xterm" interface (the print modes "xterm" and
  2515 "xterm_color" are still available for direct use in a suitable
  2516 terminal);
  2517 
  2518 
  2519 
  2520 New in Isabelle99-2 (February 2001)
  2521 -----------------------------------
  2522 
  2523 *** Overview of INCOMPATIBILITIES ***
  2524 
  2525 * HOL: please note that theories in the Library and elsewhere often use the
  2526 new-style (Isar) format; to refer to their theorems in an ML script you must
  2527 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2528 
  2529 * HOL: inductive package no longer splits induction rule aggressively,
  2530 but only as far as specified by the introductions given; the old
  2531 format may be recovered via ML function complete_split_rule or attribute
  2532 'split_rule (complete)';
  2533 
  2534 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2535 gfp_Tarski to gfp_unfold;
  2536 
  2537 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2538 
  2539 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2540 relation); infix "^^" has been renamed "``"; infix "``" has been
  2541 renamed "`"; "univalent" has been renamed "single_valued";
  2542 
  2543 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2544 operation;
  2545 
  2546 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2547 
  2548 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2549 
  2550 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2551 consequence, it is no longer monotonic wrt. the local goal context
  2552 (which is now passed through the inductive cases);
  2553 
  2554 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2555 \<gg> to \<ggreater>;
  2556 
  2557 
  2558 *** Document preparation ***
  2559 
  2560 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2561 available: are "it" for near math-mode best-style output, "sl" for
  2562 slanted text style, and "tt" for plain type-writer; if no
  2563 \isabellestyle command is given, output is according to slanted
  2564 type-writer);
  2565 
  2566 * support sub/super scripts (for single symbols only), input syntax is
  2567 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2568 
  2569 * some more standard symbols; see Appendix A of the system manual for
  2570 the complete list of symbols defined in isabellesym.sty;
  2571 
  2572 * improved isabelle style files; more abstract symbol implementation
  2573 (should now use \isamath{...} and \isatext{...} in custom symbol
  2574 definitions);
  2575 
  2576 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2577 state; Note that presentation of goal states does not conform to
  2578 actual human-readable proof documents.  Please do not include goal
  2579 states into document output unless you really know what you are doing!
  2580 
  2581 * proper indentation of antiquoted output with proportional LaTeX
  2582 fonts;
  2583 
  2584 * no_document ML operator temporarily disables LaTeX document
  2585 generation;
  2586 
  2587 * isatool unsymbolize tunes sources for plain ASCII communication;
  2588 
  2589 
  2590 *** Isar ***
  2591 
  2592 * Pure: Isar now suffers initial goal statements to contain unbound
  2593 schematic variables (this does not conform to actual readable proof
  2594 documents, due to unpredictable outcome and non-compositional proof
  2595 checking); users who know what they are doing may use schematic goals
  2596 for Prolog-style synthesis of proven results;
  2597 
  2598 * Pure: assumption method (an implicit finishing) now handles actual
  2599 rules as well;
  2600 
  2601 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  2602 initial goal, declare "that" only as Pure intro (only for single
  2603 steps); the "that" rule assumption may now be involved in implicit
  2604 finishing, thus ".." becomes a feasible for trivial obtains;
  2605 
  2606 * Pure: default proof step now includes 'intro_classes'; thus trivial
  2607 instance proofs may be performed by "..";
  2608 
  2609 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  2610 statements as well;
  2611 
  2612 * Pure: more robust selection of calculational rules;
  2613 
  2614 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  2615 rule (as well as the assumption rule);
  2616 
  2617 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  2618 lemmas, using the graph browser tool;
  2619 
  2620 * Pure: predict failure of "show" in interactive mode;
  2621 
  2622 * Pure: 'thms_containing' now takes actual terms as arguments;
  2623 
  2624 * HOL: improved method 'induct' --- now handles non-atomic goals
  2625 (potential INCOMPATIBILITY); tuned error handling;
  2626 
  2627 * HOL: cases and induct rules now provide explicit hints about the
  2628 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  2629 any remaining facts are inserted into the goal verbatim;
  2630 
  2631 * HOL: local contexts (aka cases) may now contain term bindings as
  2632 well; the 'cases' and 'induct' methods new provide a ?case binding for
  2633 the result to be shown in each case;
  2634 
  2635 * HOL: added 'recdef_tc' command;
  2636 
  2637 * isatool convert assists in eliminating legacy ML scripts;
  2638 
  2639 
  2640 *** HOL ***
  2641 
  2642 * HOL/Library: a collection of generic theories to be used together
  2643 with main HOL; the theory loader path already includes this directory
  2644 by default; the following existing theories have been moved here:
  2645 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  2646 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  2647 
  2648 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  2649 modelling and verification task performed in Isabelle/HOL +
  2650 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  2651 
  2652 * HOL/Algebra: special summation operator SUM no longer exists, it has
  2653 been replaced by setsum; infix 'assoc' now has priority 50 (like
  2654 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  2655 'domain', this makes the theory consistent with mathematical
  2656 literature;
  2657 
  2658 * HOL basics: added overloaded operations "inverse" and "divide"
  2659 (infix "/"), syntax for generic "abs" operation, generic summation
  2660 operator \<Sum>;
  2661 
  2662 * HOL/typedef: simplified package, provide more useful rules (see also
  2663 HOL/subset.thy);
  2664 
  2665 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  2666 now expressed as a proper nested rule (old-style tactic scripts may
  2667 require atomize_strip_tac to cope with non-atomic premises);
  2668 
  2669 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  2670 to "split_conv" (old name still available for compatibility);
  2671 
  2672 * HOL: improved concrete syntax for strings (e.g. allows translation
  2673 rules with string literals);
  2674 
  2675 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  2676  and Fleuriot's mechanization of analysis, including the transcendental
  2677  functions for the reals;
  2678 
  2679 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  2680 
  2681 
  2682 *** CTT ***
  2683 
  2684 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2685 "lam" is displayed as TWO lambda-symbols
  2686 
  2687 * CTT: theory Main now available, containing everything (that is, Bool
  2688 and Arith);
  2689 
  2690 
  2691 *** General ***
  2692 
  2693 * Pure: the Simplifier has been implemented properly as a derived rule
  2694 outside of the actual kernel (at last!); the overall performance
  2695 penalty in practical applications is about 50%, while reliability of
  2696 the Isabelle inference kernel has been greatly improved;
  2697 
  2698 * print modes "brackets" and "no_brackets" control output of nested =>
  2699 (types) and ==> (props); the default behaviour is "brackets";
  2700 
  2701 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2702 as assumptions as well;
  2703 
  2704 * system: support Poly/ML 4.0;
  2705 
  2706 * system: isatool install handles KDE version 1 or 2;
  2707 
  2708 
  2709 
  2710 New in Isabelle99-1 (October 2000)
  2711 ----------------------------------
  2712 
  2713 *** Overview of INCOMPATIBILITIES ***
  2714 
  2715 * HOL: simplification of natural numbers is much changed; to partly
  2716 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  2717 issue the following ML commands:
  2718 
  2719   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  2720   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  2721 
  2722 * HOL: simplification no longer dives into case-expressions; this is
  2723 controlled by "t.weak_case_cong" for each datatype t;
  2724 
  2725 * HOL: nat_less_induct renamed to less_induct;
  2726 
  2727 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  2728 fixsome to patch .thy and .ML sources automatically;
  2729 
  2730   select_equality  -> some_equality
  2731   select_eq_Ex     -> some_eq_ex
  2732   selectI2EX       -> someI2_ex
  2733   selectI2         -> someI2
  2734   selectI          -> someI
  2735   select1_equality -> some1_equality
  2736   Eps_sym_eq       -> some_sym_eq_trivial
  2737   Eps_eq           -> some_eq_trivial
  2738 
  2739 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  2740 
  2741 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  2742 instead);
  2743 
  2744 * HOL: the recursion equations generated by 'recdef' are now called
  2745 f.simps instead of f.rules;
  2746 
  2747 * HOL: qed_spec_mp now also handles bounded ALL as well;
  2748 
  2749 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  2750 sometimes be needed;
  2751 
  2752 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  2753 
  2754 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  2755 
  2756 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  2757 product is now "<*>" instead of "Times"; the lexicographic product is
  2758 now "<*lex*>" instead of "**";
  2759 
  2760 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  2761 of main HOL, but was unused); better use HOL's datatype package;
  2762 
  2763 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  2764 the old syntax may be recovered as follows:
  2765 
  2766   syntax (symbols)
  2767     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  2768       (infixl "\\<oplus>" 100)
  2769 
  2770 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2771 
  2772 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  2773 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  2774 internally;
  2775 
  2776 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  2777 changed from A/r to A//r;
  2778 
  2779 * ZF: new treatment of arithmetic (nat & int) may break some old
  2780 proofs;
  2781 
  2782 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  2783 rulify -> rule_format, elimify -> elim_format, ...);
  2784 
  2785 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2786 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  2787 should have to change intro!! to intro? only); replaced "delrule" by
  2788 "rule del";
  2789 
  2790 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  2791 
  2792 * Provers: strengthened force_tac by using new first_best_tac;
  2793 
  2794 * LaTeX document preparation: several changes of isabelle.sty (see
  2795 lib/texinputs);
  2796 
  2797 
  2798 *** Document preparation ***
  2799 
  2800 * formal comments (text blocks etc.) in new-style theories may now
  2801 contain antiquotations of thm/prop/term/typ/text to be presented
  2802 according to latex print mode; concrete syntax is like this:
  2803 @{term[show_types] "f(x) = a + x"};
  2804 
  2805 * isatool mkdir provides easy setup of Isabelle session directories,
  2806 including proper document sources;
  2807 
  2808 * generated LaTeX sources are now deleted after successful run
  2809 (isatool document -c); may retain a copy somewhere else via -D option
  2810 of isatool usedir;
  2811 
  2812 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  2813 style files, achieving self-contained LaTeX sources and simplifying
  2814 LaTeX debugging;
  2815 
  2816 * old-style theories now produce (crude) LaTeX output as well;
  2817 
  2818 * browser info session directories are now self-contained (may be put
  2819 on WWW server seperately); improved graphs of nested sessions; removed
  2820 graph for 'all sessions';
  2821 
  2822 * several improvements in isabelle style files; \isabellestyle{it}
  2823 produces fake math mode output; \isamarkupheader is now \section by
  2824 default; see lib/texinputs/isabelle.sty etc.;
  2825 
  2826 
  2827 *** Isar ***
  2828 
  2829 * Isar/Pure: local results and corresponding term bindings are now
  2830 subject to Hindley-Milner polymorphism (similar to ML); this
  2831 accommodates incremental type-inference very nicely;
  2832 
  2833 * Isar/Pure: new derived language element 'obtain' supports
  2834 generalized existence reasoning;
  2835 
  2836 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  2837 support accumulation of results, without applying any rules yet;
  2838 useful to collect intermediate results without explicit name
  2839 references, and for use with transitivity rules with more than 2
  2840 premises;
  2841 
  2842 * Isar/Pure: scalable support for case-analysis type proofs: new
  2843 'case' language element refers to local contexts symbolically, as
  2844 produced by certain proof methods; internally, case names are attached
  2845 to theorems as "tags";
  2846 
  2847 * Isar/Pure: theory command 'hide' removes declarations from
  2848 class/type/const name spaces;
  2849 
  2850 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  2851 indicate potential overloading;
  2852 
  2853 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  2854 
  2855 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  2856 "{a,b,c}" instead of {a,b,c};
  2857 
  2858 * Isar/Pure now provides its own version of intro/elim/dest
  2859 attributes; useful for building new logics, but beware of confusion
  2860 with the version in Provers/classical;
  2861 
  2862 * Isar/Pure: the local context of (non-atomic) goals is provided via
  2863 case name 'antecedent';
  2864 
  2865 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  2866 to the current context is now done automatically);
  2867 
  2868 * Isar/Pure: theory command 'method_setup' provides a simple interface
  2869 for definining proof methods in ML;
  2870 
  2871 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2872 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  2873 most cases, one should have to change intro!! to intro? only);
  2874 replaced "delrule" by "rule del";
  2875 
  2876 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  2877 'symmetric' attribute (the latter supercedes [RS sym]);
  2878 
  2879 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  2880 method modifier); 'simp' method: 'only:' modifier removes loopers as
  2881 well (including splits);
  2882 
  2883 * Isar/Provers: Simplifier and Classical methods now support all kind
  2884 of modifiers used in the past, including 'cong', 'iff', etc.
  2885 
  2886 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  2887 of Simplifier and Classical reasoner);
  2888 
  2889 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  2890 now support named cases; major packages (inductive, datatype, primrec,
  2891 recdef) support case names and properly name parameters;
  2892 
  2893 * Isar/HOL: new transitivity rules for substitution in inequalities --
  2894 monotonicity conditions are extracted to be proven at end of
  2895 calculations;
  2896 
  2897 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  2898 method anyway;
  2899 
  2900 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  2901 split_if split_if_asm; datatype package provides theorems foo.splits =
  2902 foo.split foo.split_asm for each datatype;
  2903 
  2904 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  2905 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  2906 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  2907 use "(cases (simplified))" method in proper proof texts);
  2908 
  2909 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  2910 
  2911 * Isar: names of theorems etc. may be natural numbers as well;
  2912 
  2913 * Isar: 'pr' command: optional arguments for goals_limit and
  2914 ProofContext.prems_limit; no longer prints theory contexts, but only
  2915 proof states;
  2916 
  2917 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  2918 additional print modes to be specified; e.g. "pr(latex)" will print
  2919 proof state according to the Isabelle LaTeX style;
  2920 
  2921 * Isar: improved support for emulating tactic scripts, including proof
  2922 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  2923 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  2924 (for HOL datatypes);
  2925 
  2926 * Isar: simplified (more robust) goal selection of proof methods: 1st
  2927 goal, all goals, or explicit goal specifier (tactic emulation); thus
  2928 'proof method scripts' have to be in depth-first order;
  2929 
  2930 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  2931 
  2932 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  2933 should instead use individual commands for printing items
  2934 (print_commands, print_methods etc.);
  2935 
  2936 * Isar: added 'nothing' --- the empty list of theorems;
  2937 
  2938 
  2939 *** HOL ***
  2940 
  2941 * HOL/MicroJava: formalization of a fragment of Java, together with a
  2942 corresponding virtual machine and a specification of its bytecode
  2943 verifier and a lightweight bytecode verifier, including proofs of
  2944 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  2945 Cornelia Pusch (see also the homepage of project Bali at
  2946 http://isabelle.in.tum.de/Bali/);
  2947 
  2948 * HOL/Algebra: new theory of rings and univariate polynomials, by
  2949 Clemens Ballarin;
  2950 
  2951 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  2952 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  2953 Rasmussen;
  2954 
  2955 * HOL/Lattice: fundamental concepts of lattice theory and order
  2956 structures, including duals, properties of bounds versus algebraic
  2957 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  2958 Theorem for complete lattices etc.; may also serve as a demonstration
  2959 for abstract algebraic reasoning using axiomatic type classes, and
  2960 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  2961 
  2962 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  2963 von Oheimb;
  2964 
  2965 * HOL/IMPP: extension of IMP with local variables and mutually
  2966 recursive procedures, by David von Oheimb;
  2967 
  2968 * HOL/Lambda: converted into new-style theory and document;
  2969 
  2970 * HOL/ex/Multiquote: example of multiple nested quotations and
  2971 anti-quotations -- basically a generalized version of de-Bruijn
  2972 representation; very useful in avoiding lifting of operations;
  2973 
  2974 * HOL/record: added general record equality rule to simpset; fixed
  2975 select-update simplification procedure to handle extended records as
  2976 well; admit "r" as field name;
  2977 
  2978 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  2979 other numeric types and also as the identity of groups, rings, etc.;
  2980 
  2981 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  2982 Types nat and int belong to this axclass;
  2983 
  2984 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  2985    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  2986    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  2987   two terms #m*u and #n*u are replaced by #(m+n)*u
  2988     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  2989   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  2990     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  2991 
  2992 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  2993 powerful prover for predicate logic but knows nothing of clasets; see
  2994 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  2995 
  2996 * HOL: new version of "case_tac" subsumes both boolean case split and
  2997 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  2998 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  2999 
  3000 * HOL: simplification no longer dives into case-expressions: only the
  3001 selector expression is simplified, but not the remaining arms; to
  3002 enable full simplification of case-expressions for datatype t, you may
  3003 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3004 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3005 
  3006 * HOL/recdef: the recursion equations generated by 'recdef' for
  3007 function 'f' are now called f.simps instead of f.rules; if all
  3008 termination conditions are proved automatically, these simplification
  3009 rules are added to the simpset, as in primrec; rules may be named
  3010 individually as well, resulting in a separate list of theorems for
  3011 each equation;
  3012 
  3013 * HOL/While is a new theory that provides a while-combinator. It
  3014 permits the definition of tail-recursive functions without the
  3015 provision of a termination measure. The latter is necessary once the
  3016 invariant proof rule for while is applied.
  3017 
  3018 * HOL: new (overloaded) notation for the set of elements below/above
  3019 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3020 
  3021 * HOL: theorems impI, allI, ballI bound as "strip";
  3022 
  3023 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3024 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3025 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3026 
  3027 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3028 
  3029 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3030 main HOL, but was unused);
  3031 
  3032 * HOL: fewer consts declared as global (e.g. have to refer to
  3033 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3034 
  3035 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3036 in case of overlap with user translations (e.g. judgements over
  3037 tuples); (note that the underlying logical represenation is still
  3038 bogus);
  3039 
  3040 
  3041 *** ZF ***
  3042 
  3043 * ZF: simplification automatically cancels common terms in arithmetic
  3044 expressions over nat and int;
  3045 
  3046 * ZF: new treatment of nat to minimize type-checking: all operators
  3047 coerce their operands to a natural number using the function natify,
  3048 making the algebraic laws unconditional;
  3049 
  3050 * ZF: as above, for int: operators coerce their operands to an integer
  3051 using the function intify;
  3052 
  3053 * ZF: the integer library now contains many of the usual laws for the
  3054 orderings, including $<=, and monotonicity laws for $+ and $*;
  3055 
  3056 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3057 simplification;
  3058 
  3059 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3060 to the simplifier and classical reasoner simultaneously;
  3061 
  3062 
  3063 *** General ***
  3064 
  3065 * Provers: blast_tac now handles actual object-logic rules as
  3066 assumptions; note that auto_tac uses blast_tac internally as well;
  3067 
  3068 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3069 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3070 
  3071 * Provers: delrules now handles destruct rules as well (no longer need
  3072 explicit make_elim);
  3073 
  3074 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3075   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3076 use instead the strong form,
  3077   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3078 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3079 from destruct-rules;
  3080 
  3081 * Provers: Simplifier.easy_setup provides a fast path to basic
  3082 Simplifier setup for new object-logics;
  3083 
  3084 * Pure: AST translation rules no longer require constant head on LHS;
  3085 
  3086 * Pure: improved name spaces: ambiguous output is qualified; support
  3087 for hiding of names;
  3088 
  3089 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3090 XSYMBOL_HOME; no longer need to do manual configuration in most
  3091 situations;
  3092 
  3093 * system: compression of ML heaps images may now be controlled via -c
  3094 option of isabelle and isatool usedir (currently only observed by
  3095 Poly/ML);
  3096 
  3097 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3098 useful for remote X11);
  3099 
  3100 * system: provide TAGS file for Isabelle sources;
  3101 
  3102 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3103 order;
  3104 
  3105 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3106 timing flag supersedes proof_timing and Toplevel.trace;
  3107 
  3108 * ML: new combinators |>> and |>>> for incremental transformations
  3109 with secondary results (e.g. certain theory extensions):
  3110 
  3111 * ML: PureThy.add_defs gets additional argument to indicate potential
  3112 overloading (usually false);
  3113 
  3114 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3115 results;
  3116 
  3117 
  3118 
  3119 New in Isabelle99 (October 1999)
  3120 --------------------------------
  3121 
  3122 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3123 
  3124 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3125 are no longer simplified.  (This allows the simplifier to unfold recursive
  3126 functional programs.)  To restore the old behaviour, declare
  3127 
  3128     Delcongs [if_weak_cong];
  3129 
  3130 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3131 complement;
  3132 
  3133 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3134 
  3135 * HOL/datatype: mutual_induct_tac no longer exists --
  3136   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3137 
  3138 * HOL/typedef: fixed type inference for representing set; type
  3139 arguments now have to occur explicitly on the rhs as type constraints;
  3140 
  3141 * ZF: The con_defs part of an inductive definition may no longer refer
  3142 to constants declared in the same theory;
  3143 
  3144 * HOL, ZF: the function mk_cases, generated by the inductive
  3145 definition package, has lost an argument.  To simplify its result, it
  3146 uses the default simpset instead of a supplied list of theorems.
  3147 
  3148 * HOL/List: the constructors of type list are now Nil and Cons;
  3149 
  3150 * Simplifier: the type of the infix ML functions
  3151         setSSolver addSSolver setSolver addSolver
  3152 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3153 for packaging solvers. A solver is created via
  3154         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3155 where the string argument is only a comment.
  3156 
  3157 
  3158 *** Proof tools ***
  3159 
  3160 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3161 decision procedure for linear arithmetic. Currently it is used for
  3162 types `nat', `int', and `real' in HOL (see below); it can, should and
  3163 will be instantiated for other types and logics as well.
  3164 
  3165 * The simplifier now accepts rewrite rules with flexible heads, eg
  3166      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3167   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3168   matching.
  3169 
  3170 
  3171 *** General ***
  3172 
  3173 * New Isabelle/Isar subsystem provides an alternative to traditional
  3174 tactical theorem proving; together with the ProofGeneral/isar user
  3175 interface it offers an interactive environment for developing human
  3176 readable proof documents (Isar == Intelligible semi-automated
  3177 reasoning); for further information see isatool doc isar-ref,
  3178 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3179 
  3180 * improved and simplified presentation of theories: better HTML markup
  3181 (including colors), graph views in several sizes; isatool usedir now
  3182 provides a proper interface for user theories (via -P option); actual
  3183 document preparation based on (PDF)LaTeX is available as well (for
  3184 new-style theories only); see isatool doc system for more information;
  3185 
  3186 * native support for Proof General, both for classic Isabelle and
  3187 Isabelle/Isar;
  3188 
  3189 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3190 using the graph browser tool;
  3191 
  3192 * Isabelle manuals now also available as PDF;
  3193 
  3194 * theory loader rewritten from scratch (may not be fully
  3195 bug-compatible); old loadpath variable has been replaced by show_path,
  3196 add_path, del_path, reset_path functions; new operations such as
  3197 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3198 isatool doc ref);
  3199 
  3200 * improved isatool install: option -k creates KDE application icon,
  3201 option -p DIR installs standalone binaries;
  3202 
  3203 * added ML_PLATFORM setting (useful for cross-platform installations);
  3204 more robust handling of platform specific ML images for SML/NJ;
  3205 
  3206 * the settings environment is now statically scoped, i.e. it is never
  3207 created again in sub-processes invoked from isabelle, isatool, or
  3208 Isabelle;
  3209 
  3210 * path element specification '~~' refers to '$ISABELLE_HOME';
  3211 
  3212 * in locales, the "assumes" and "defines" parts may be omitted if
  3213 empty;
  3214 
  3215 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3216 long arrows);
  3217 
  3218 * new print_mode "HTML";
  3219 
  3220 * new flag show_tags controls display of tags of theorems (which are
  3221 basically just comments that may be attached by some tools);
  3222 
  3223 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3224 mode and goal output format:
  3225 
  3226 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3227 244c244
  3228 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3229 ---
  3230 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3231 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3232 181c181
  3233 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3234 ---
  3235 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3236 
  3237 * function bind_thms stores lists of theorems (cf. bind_thm);
  3238 
  3239 * new shorthand tactics ftac, eatac, datac, fatac;
  3240 
  3241 * qed (and friends) now accept "" as result name; in that case the
  3242 theorem is not stored, but proper checks and presentation of the
  3243 result still apply;
  3244 
  3245 * theorem database now also indexes constants "Trueprop", "all",
  3246 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3247 
  3248 
  3249 *** HOL ***
  3250 
  3251 ** HOL arithmetic **
  3252 
  3253 * There are now decision procedures for linear arithmetic over nat and
  3254 int:
  3255 
  3256 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3257 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3258 are treated as atomic; subformulae not involving type `nat' or `int'
  3259 are ignored; quantified subformulae are ignored unless they are
  3260 positive universal or negative existential. The tactic has to be
  3261 invoked by hand and can be a little bit slow. In particular, the
  3262 running time is exponential in the number of occurrences of `min' and
  3263 `max', and `-' on `nat'.
  3264 
  3265 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3266 (negated) (in)equalities among the premises and the conclusion into
  3267 account (i.e. no compound formulae) and does not know about `min' and
  3268 `max', and `-' on `nat'. It is fast and is used automatically by the
  3269 simplifier.
  3270 
  3271 NB: At the moment, these decision procedures do not cope with mixed
  3272 nat/int formulae where the two parts interact, such as `m < n ==>
  3273 int(m) < int(n)'.
  3274 
  3275 * HOL/Numeral provides a generic theory of numerals (encoded
  3276 efficiently as bit strings); setup for types nat/int/real is in place;
  3277 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3278 int, existing theories and proof scripts may require a few additional
  3279 type constraints;
  3280 
  3281 * integer division and remainder can now be performed on constant
  3282 arguments;
  3283 
  3284 * many properties of integer multiplication, division and remainder
  3285 are now available;
  3286 
  3287 * An interface to the Stanford Validity Checker (SVC) is available through the
  3288 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3289 are proved automatically.  SVC must be installed separately, and its results
  3290 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3291 invocation of the underlying oracle).  For SVC see
  3292   http://verify.stanford.edu/SVC
  3293 
  3294 * IsaMakefile: the HOL-Real target now builds an actual image;
  3295 
  3296 
  3297 ** HOL misc **
  3298 
  3299 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3300 (in Isabelle/Isar) -- by Gertrud Bauer;
  3301 
  3302 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3303 analysis for assembly languages with subtypes;
  3304 
  3305 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3306 -- avoids syntactic ambiguities and treats state, transition, and
  3307 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3308 changed syntax and (many) tactics;
  3309 
  3310 * HOL/inductive: Now also handles more general introduction rules such
  3311   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3312   theorems are now maintained within the theory (maintained via the
  3313   "mono" attribute);
  3314 
  3315 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3316   (using function types) such as
  3317 
  3318   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3319 
  3320 * HOL/record: record_simproc (part of the default simpset) takes care
  3321 of selectors applied to updated records; record_split_tac is no longer
  3322 part of the default claset; update_defs may now be removed from the
  3323 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3324 
  3325   claset_ref () := claset() addSWrapper record_split_wrapper;
  3326   Delsimprocs [record_simproc]
  3327 
  3328 * HOL/typedef: fixed type inference for representing set; type
  3329 arguments now have to occur explicitly on the rhs as type constraints;
  3330 
  3331 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3332 names rather than an ML expression;
  3333 
  3334 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3335 supplied later.  Program schemes can be defined, such as
  3336     "While B C s = (if B s then While B C (C s) else s)"
  3337 where the well-founded relation can be chosen after B and C have been given.
  3338 
  3339 * HOL/List: the constructors of type list are now Nil and Cons;
  3340 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3341 course, ML tools referring to List.list.op # etc. have to be adapted;
  3342 
  3343 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3344 disabled by default; run isabelle with option -m HOL to get back to
  3345 the original Gordon/HOL-style output;
  3346 
  3347 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3348 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3349 
  3350 * HOL basic syntax simplified (more orthogonal): all variants of
  3351 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3352 Eps operator is provided as well: "SOME x. P[x]";
  3353 
  3354 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3355 
  3356 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3357 thus available for user theories;
  3358 
  3359 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3360 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3361 time;
  3362 
  3363 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3364 several times and then mp;
  3365 
  3366 
  3367 *** LK ***
  3368 
  3369 * the notation <<...>> is now available as a notation for sequences of
  3370 formulas;
  3371 
  3372 * the simplifier is now installed
  3373 
  3374 * the axiom system has been generalized (thanks to Soren Heilmann)
  3375 
  3376 * the classical reasoner now has a default rule database
  3377 
  3378 
  3379 *** ZF ***
  3380 
  3381 * new primrec section allows primitive recursive functions to be given
  3382 directly (as in HOL) over datatypes and the natural numbers;
  3383 
  3384 * new tactics induct_tac and exhaust_tac for induction (or case
  3385 analysis) over datatypes and the natural numbers;
  3386 
  3387 * the datatype declaration of type T now defines the recursor T_rec;
  3388 
  3389 * simplification automatically does freeness reasoning for datatype
  3390 constructors;
  3391 
  3392 * automatic type-inference, with AddTCs command to insert new
  3393 type-checking rules;
  3394 
  3395 * datatype introduction rules are now added as Safe Introduction rules
  3396 to the claset;
  3397 
  3398 * the syntax "if P then x else y" is now available in addition to
  3399 if(P,x,y);
  3400 
  3401 
  3402 *** Internal programming interfaces ***
  3403 
  3404 * tuned simplifier trace output; new flag debug_simp;
  3405 
  3406 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3407 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3408 
  3409 * AxClass.axclass_tac lost the theory argument;
  3410 
  3411 * tuned current_goals_markers semantics: begin / end goal avoids
  3412 printing empty lines;
  3413 
  3414 * removed prs and prs_fn hook, which was broken because it did not
  3415 include \n in its semantics, forcing writeln to add one
  3416 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3417 string -> unit if you really want to output text without newline;
  3418 
  3419 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3420 plain output, interface builders may have to enable 'isabelle_font'
  3421 mode to get Isabelle font glyphs as before;
  3422 
  3423 * refined token_translation interface; INCOMPATIBILITY: output length
  3424 now of type real instead of int;
  3425 
  3426 * theory loader actions may be traced via new ThyInfo.add_hook
  3427 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3428 your own database of information attached to *whole* theories -- as
  3429 opposed to intra-theory data slots offered via TheoryDataFun;
  3430 
  3431 * proper handling of dangling sort hypotheses (at last!);
  3432 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3433 extra sort hypotheses that can be witnessed from the type signature;
  3434 the force_strip_shyps flag is gone, any remaining shyps are simply
  3435 left in the theorem (with a warning issued by strip_shyps_warning);
  3436 
  3437 
  3438 
  3439 New in Isabelle98-1 (October 1998)
  3440 ----------------------------------
  3441 
  3442 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3443 
  3444 * several changes of automated proof tools;
  3445 
  3446 * HOL: major changes to the inductive and datatype packages, including
  3447 some minor incompatibilities of theory syntax;
  3448 
  3449 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3450 called `inj_on';
  3451 
  3452 * HOL: removed duplicate thms in Arith:
  3453   less_imp_add_less  should be replaced by  trans_less_add1
  3454   le_imp_add_le      should be replaced by  trans_le_add1
  3455 
  3456 * HOL: unary minus is now overloaded (new type constraints may be
  3457 required);
  3458 
  3459 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3460 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3461 now taken as an integer constant.
  3462 
  3463 * Pure: ML function 'theory_of' renamed to 'theory';
  3464 
  3465 
  3466 *** Proof tools ***
  3467 
  3468 * Simplifier:
  3469   1. Asm_full_simp_tac is now more aggressive.
  3470      1. It will sometimes reorient premises if that increases their power to
  3471         simplify.
  3472      2. It does no longer proceed strictly from left to right but may also
  3473         rotate premises to achieve further simplification.
  3474      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3475      old Asm_full_simp_tac in that it does not rotate premises.
  3476   2. The simplifier now knows a little bit about nat-arithmetic.
  3477 
  3478 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3479 allows for selected deletion of wrappers, by introduction of names for
  3480 wrapper functionals.  This implies that addbefore, addSbefore,
  3481 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3482 and that adding two tactics with the same name overwrites the first
  3483 one (emitting a warning).
  3484   type wrapper = (int -> tactic) -> (int -> tactic)
  3485   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3486   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3487   delWrapper, delSWrapper: claset *  string            -> claset
  3488   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3489 
  3490 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3491 semantics; addbefore now affects only the unsafe part of step_tac
  3492 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3493 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3494 by Force_tac;
  3495 
  3496 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3497 compWrapper; added safe wrapper (and access functions for it);
  3498 
  3499 * HOL/split_all_tac is now much faster and fails if there is nothing
  3500 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3501 and the names of the automatically generated variables have changed.
  3502 split_all_tac has moved within claset() from unsafe wrappers to safe
  3503 wrappers, which means that !!-bound variables are split much more
  3504 aggressively, and safe_tac and clarify_tac now split such variables.
  3505 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3506 Note: the same holds for record_split_tac, which does the job of
  3507 split_all_tac for record fields.
  3508 
  3509 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3510 permanently to the default simpset using Addsplits just like
  3511 Addsimps. They can be removed via Delsplits just like
  3512 Delsimps. Lower-case versions are also available.
  3513 
  3514 * HOL/Simplifier: The rule split_if is now part of the default
  3515 simpset. This means that the simplifier will eliminate all occurrences
  3516 of if-then-else in the conclusion of a goal. To prevent this, you can
  3517 either remove split_if completely from the default simpset by
  3518 `Delsplits [split_if]' or remove it in a specific call of the
  3519 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3520 other case splitting rules to/from the default simpset: every datatype
  3521 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3522 t is the name of the datatype).
  3523 
  3524 * Classical reasoner / Simplifier combination: new force_tac (and
  3525 derivatives Force_tac, force) combines rewriting and classical
  3526 reasoning (and whatever other tools) similarly to auto_tac, but is
  3527 aimed to solve the given subgoal completely.
  3528 
  3529 
  3530 *** General ***
  3531 
  3532 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3533 and `goalw': the theory is no longer needed as an explicit argument -
  3534 the current theory context is used; assumptions are no longer returned
  3535 at the ML-level unless one of them starts with ==> or !!; it is
  3536 recommended to convert to these new commands using isatool fixgoal
  3537 (backup your sources first!);
  3538 
  3539 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3540 the current theory context, and 'theory' to lookup stored theories;
  3541 
  3542 * new theory section 'locale' for declaring constants, assumptions and
  3543 definitions that have local scope;
  3544 
  3545 * new theory section 'nonterminals' for purely syntactic types;
  3546 
  3547 * new theory section 'setup' for generic ML setup functions
  3548 (e.g. package initialization);
  3549 
  3550 * the distribution now includes Isabelle icons: see
  3551 lib/logo/isabelle-{small,tiny}.xpm;
  3552 
  3553 * isatool install - install binaries with absolute references to
  3554 ISABELLE_HOME/bin;
  3555 
  3556 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3557 
  3558 * print mode 'emacs' reserved for Isamode;
  3559 
  3560 * support multiple print (ast) translations per constant name;
  3561 
  3562 * theorems involving oracles are now printed with a suffixed [!];
  3563 
  3564 
  3565 *** HOL ***
  3566 
  3567 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3568 
  3569 * HOL/inductive package reorganized and improved: now supports mutual
  3570 definitions such as
  3571 
  3572   inductive EVEN ODD
  3573     intrs
  3574       null "0 : EVEN"
  3575       oddI "n : EVEN ==> Suc n : ODD"
  3576       evenI "n : ODD ==> Suc n : EVEN"
  3577 
  3578 new theorem list "elims" contains an elimination rule for each of the
  3579 recursive sets; inductive definitions now handle disjunctive premises
  3580 correctly (also ZF);
  3581 
  3582 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3583 "mutual_induct" no longer exists - the induction rule is always
  3584 contained in "induct";
  3585 
  3586 
  3587 * HOL/datatype package re-implemented and greatly improved: now
  3588 supports mutually recursive datatypes such as
  3589 
  3590   datatype
  3591     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3592             | SUM ('a aexp) ('a aexp)
  3593             | DIFF ('a aexp) ('a aexp)
  3594             | NUM 'a
  3595   and
  3596     'a bexp = LESS ('a aexp) ('a aexp)
  3597             | AND ('a bexp) ('a bexp)
  3598             | OR ('a bexp) ('a bexp)
  3599 
  3600 as well as indirectly recursive datatypes such as
  3601 
  3602   datatype
  3603     ('a, 'b) term = Var 'a
  3604                   | App 'b ((('a, 'b) term) list)
  3605 
  3606 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  3607 induction on mutually / indirectly recursive datatypes.
  3608 
  3609 Primrec equations are now stored in theory and can be accessed via
  3610 <function_name>.simps.
  3611 
  3612 INCOMPATIBILITIES:
  3613 
  3614   - Theories using datatypes must now have theory Datatype as an
  3615     ancestor.
  3616   - The specific <typename>.induct_tac no longer exists - use the
  3617     generic induct_tac instead.
  3618   - natE has been renamed to nat.exhaust - use exhaust_tac
  3619     instead of res_inst_tac ... natE. Note that the variable
  3620     names in nat.exhaust differ from the names in natE, this
  3621     may cause some "fragile" proofs to fail.
  3622   - The theorems split_<typename>_case and split_<typename>_case_asm
  3623     have been renamed to <typename>.split and <typename>.split_asm.
  3624   - Since default sorts of type variables are now handled correctly,
  3625     some datatype definitions may have to be annotated with explicit
  3626     sort constraints.
  3627   - Primrec definitions no longer require function name and type
  3628     of recursive argument.
  3629 
  3630 Consider using isatool fixdatatype to adapt your theories and proof
  3631 scripts to the new package (backup your sources first!).
  3632 
  3633 
  3634 * HOL/record package: considerably improved implementation; now
  3635 includes concrete syntax for record types, terms, updates; theorems
  3636 for surjective pairing and splitting !!-bound record variables; proof
  3637 support is as follows:
  3638 
  3639   1) standard conversions (selectors or updates applied to record
  3640 constructor terms) are part of the standard simpset;
  3641 
  3642   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  3643 made part of standard simpset and claset via addIffs;
  3644 
  3645   3) a tactic for record field splitting (record_split_tac) is part of
  3646 the standard claset (addSWrapper);
  3647 
  3648 To get a better idea about these rules you may retrieve them via
  3649 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  3650 the name of your record type.
  3651 
  3652 The split tactic 3) conceptually simplifies by the following rule:
  3653 
  3654   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  3655 
  3656 Thus any record variable that is bound by meta-all will automatically
  3657 blow up into some record constructor term, consequently the
  3658 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  3659 solve record problems automatically.
  3660 
  3661 
  3662 * reorganized the main HOL image: HOL/Integ and String loaded by
  3663 default; theory Main includes everything;
  3664 
  3665 * automatic simplification of integer sums and comparisons, using cancellation;
  3666 
  3667 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  3668 
  3669 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  3670 
  3671 * many new identities for unions, intersections, set difference, etc.;
  3672 
  3673 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  3674 called split_if, split_split, split_sum_case and split_nat_case (to go
  3675 with add/delsplits);
  3676 
  3677 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  3678 (?x::unit) = (); this is made part of the default simpset, which COULD
  3679 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  3680 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  3681 unit_abs_eta_conv is added in order to counter the effect of
  3682 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  3683 %u.f();
  3684 
  3685 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3686 makes more sense);
  3687 
  3688 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3689   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3690   disjointness reasoning but breaking a few old proofs.
  3691 
  3692 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3693 to 'converse' from 'inverse' (for compatibility with ZF and some
  3694 literature);
  3695 
  3696 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3697 the well-founded relation;
  3698 
  3699 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3700     Compl A.  The "Compl" syntax remains available as input syntax for this
  3701     release ONLY.
  3702 
  3703 * HOL/Update: new theory of function updates:
  3704     f(a:=b) == %x. if x=a then b else f x
  3705 may also be iterated as in f(a:=b,c:=d,...);
  3706 
  3707 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  3708 
  3709 * HOL/List:
  3710   - new function list_update written xs[i:=v] that updates the i-th
  3711     list position. May also be iterated as in xs[i:=a,j:=b,...].
  3712   - new function `upt' written [i..j(] which generates the list
  3713     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  3714     bound write [i..j], which is a shorthand for [i..j+1(].
  3715   - new lexicographic orderings and corresponding wellfoundedness theorems.
  3716 
  3717 * HOL/Arith:
  3718   - removed 'pred' (predecessor) function;
  3719   - generalized some theorems about n-1;
  3720   - many new laws about "div" and "mod";
  3721   - new laws about greatest common divisors (see theory ex/Primes);
  3722 
  3723 * HOL/Relation: renamed the relational operator r^-1 "converse"
  3724 instead of "inverse";
  3725 
  3726 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  3727   of the multiset ordering;
  3728 
  3729 * directory HOL/Real: a construction of the reals using Dedekind cuts
  3730   (not included by default);
  3731 
  3732 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  3733 
  3734 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  3735   programs, i.e. different program variables may have different types.
  3736 
  3737 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3738   [previously, this check worked only if the rewrite rule was unconditional]
  3739   Now rew can involve either definitions or equalities (either == or =).
  3740 
  3741 
  3742 *** ZF ***
  3743 
  3744 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  3745   only the theorems proved on ZF.ML;
  3746 
  3747 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3748   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3749   disjointness reasoning but breaking a few old proofs.
  3750 
  3751 * ZF/Update: new theory of function updates
  3752     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  3753   may also be iterated as in f(a:=b,c:=d,...);
  3754 
  3755 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  3756 
  3757 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3758   [previously, this check worked only if the rewrite rule was unconditional]
  3759   Now rew can involve either definitions or equalities (either == or =).
  3760 
  3761 * case_tac provided for compatibility with HOL
  3762     (like the old excluded_middle_tac, but with subgoals swapped)
  3763 
  3764 
  3765 *** Internal programming interfaces ***
  3766 
  3767 * Pure: several new basic modules made available for general use, see
  3768 also src/Pure/README;
  3769 
  3770 * improved the theory data mechanism to support encapsulation (data
  3771 kind name replaced by private Object.kind, acting as authorization
  3772 key); new type-safe user interface via functor TheoryDataFun; generic
  3773 print_data function becomes basically useless;
  3774 
  3775 * removed global_names compatibility flag -- all theory declarations
  3776 are qualified by default;
  3777 
  3778 * module Pure/Syntax now offers quote / antiquote translation
  3779 functions (useful for Hoare logic etc. with implicit dependencies);
  3780 see HOL/ex/Antiquote for an example use;
  3781 
  3782 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  3783 cterm -> thm;
  3784 
  3785 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  3786 subgoal;
  3787 
  3788 * Display.print_goals function moved to Locale.print_goals;
  3789 
  3790 * standard print function for goals supports current_goals_markers
  3791 variable for marking begin of proof, end of proof, start of goal; the
  3792 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  3793 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  3794 for example;
  3795 
  3796 
  3797 
  3798 New in Isabelle98 (January 1998)
  3799 --------------------------------
  3800 
  3801 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3802 
  3803 * changed lexical syntax of terms / types: dots made part of long
  3804 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  3805 
  3806 * simpset (and claset) reference variable replaced by functions
  3807 simpset / simpset_ref;
  3808 
  3809 * no longer supports theory aliases (via merge) and non-trivial
  3810 implicit merge of thms' signatures;
  3811 
  3812 * most internal names of constants changed due to qualified names;
  3813 
  3814 * changed Pure/Sequence interface (see Pure/seq.ML);
  3815 
  3816 
  3817 *** General Changes ***
  3818 
  3819 * hierachically structured name spaces (for consts, types, axms, thms
  3820 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  3821 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  3822 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  3823 long_names for fully qualified output names; NOTE: ML programs
  3824 (special tactics, packages etc.) referring to internal names may have
  3825 to be adapted to cope with fully qualified names; in case of severe
  3826 backward campatibility problems try setting 'global_names' at compile
  3827 time to have enrything declared within a flat name space; one may also
  3828 fine tune name declarations in theories via the 'global' and 'local'
  3829 section;
  3830 
  3831 * reimplemented the implicit simpset and claset using the new anytype
  3832 data filed in signatures; references simpset:simpset ref etc. are
  3833 replaced by functions simpset:unit->simpset and
  3834 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  3835 to patch your ML files accordingly;
  3836 
  3837 * HTML output now includes theory graph data for display with Java
  3838 applet or isatool browser; data generated automatically via isatool
  3839 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  3840 
  3841 * defs may now be conditional; improved rewrite_goals_tac to handle
  3842 conditional equations;
  3843 
  3844 * defs now admits additional type arguments, using TYPE('a) syntax;
  3845 
  3846 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  3847 creates a new theory node; implicit merge of thms' signatures is
  3848 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  3849 transfer:theory->thm->thm in (rare) cases;
  3850 
  3851 * improved handling of draft signatures / theories; draft thms (and
  3852 ctyps, cterms) are automatically promoted to real ones;
  3853 
  3854 * slightly changed interfaces for oracles: admit many per theory, named
  3855 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  3856 
  3857 * print_goals: optional output of const types (set show_consts and
  3858 show_types);
  3859 
  3860 * improved output of warnings (###) and errors (***);
  3861 
  3862 * subgoal_tac displays a warning if the new subgoal has type variables;
  3863 
  3864 * removed old README and Makefiles;
  3865 
  3866 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  3867 
  3868 * removed obsolete init_pps and init_database;
  3869 
  3870 * deleted the obsolete tactical STATE, which was declared by
  3871     fun STATE tacfun st = tacfun st st;
  3872 
  3873 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  3874 (which abbreviates $HOME);
  3875 
  3876 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  3877 use isatool fixseq to adapt your ML programs (this works for fully
  3878 qualified references to the Sequence structure only!);
  3879 
  3880 * use_thy no longer requires writable current directory; it always
  3881 reloads .ML *and* .thy file, if either one is out of date;
  3882 
  3883 
  3884 *** Classical Reasoner ***
  3885 
  3886 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  3887 tactics that use classical reasoning to simplify a subgoal without
  3888 splitting it into several subgoals;
  3889 
  3890 * Safe_tac: like safe_tac but uses the default claset;
  3891 
  3892 
  3893 *** Simplifier ***
  3894 
  3895 * added simplification meta rules:
  3896     (asm_)(full_)simplify: simpset -> thm -> thm;
  3897 
  3898 * simplifier.ML no longer part of Pure -- has to be loaded by object
  3899 logics (again);
  3900 
  3901 * added prems argument to simplification procedures;
  3902 
  3903 * HOL, FOL, ZF: added infix function `addsplits':
  3904   instead of `<simpset> setloop (split_tac <thms>)'
  3905   you can simply write `<simpset> addsplits <thms>'
  3906 
  3907 
  3908 *** Syntax ***
  3909 
  3910 * TYPE('a) syntax for type reflection terms;
  3911 
  3912 * no longer handles consts with name "" -- declare as 'syntax' instead;
  3913 
  3914 * pretty printer: changed order of mixfix annotation preference (again!);
  3915 
  3916 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  3917 
  3918 
  3919 *** HOL ***
  3920 
  3921 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  3922   with `addloop' of the simplifier to faciliate case splitting in premises.
  3923 
  3924 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  3925 
  3926 * HOL/Auth: new protocol proofs including some for the Internet
  3927   protocol TLS;
  3928 
  3929 * HOL/Map: new theory of `maps' a la VDM;
  3930 
  3931 * HOL/simplifier: simplification procedures nat_cancel_sums for
  3932 cancelling out common nat summands from =, <, <= (in)equalities, or
  3933 differences; simplification procedures nat_cancel_factor for
  3934 cancelling common factor from =, <, <= (in)equalities over natural
  3935 sums; nat_cancel contains both kinds of procedures, it is installed by
  3936 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  3937 
  3938 * HOL/simplifier: terms of the form
  3939   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  3940   are rewritten to
  3941   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  3942   and those of the form
  3943   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  3944   are rewritten to
  3945   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  3946 
  3947 * HOL/datatype
  3948   Each datatype `t' now comes with a theorem `split_t_case' of the form
  3949 
  3950   P(t_case f1 ... fn x) =
  3951      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  3952         ...
  3953        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  3954      )
  3955 
  3956   and a theorem `split_t_case_asm' of the form
  3957 
  3958   P(t_case f1 ... fn x) =
  3959     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  3960         ...
  3961        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  3962      )
  3963   which can be added to a simpset via `addsplits'. The existing theorems
  3964   expand_list_case and expand_option_case have been renamed to
  3965   split_list_case and split_option_case.
  3966 
  3967 * HOL/Arithmetic:
  3968   - `pred n' is automatically converted to `n-1'.
  3969     Users are strongly encouraged not to use `pred' any longer,
  3970     because it will disappear altogether at some point.
  3971   - Users are strongly encouraged to write "0 < n" rather than
  3972     "n ~= 0". Theorems and proof tools have been modified towards this
  3973     `standard'.
  3974 
  3975 * HOL/Lists:
  3976   the function "set_of_list" has been renamed "set" (and its theorems too);
  3977   the function "nth" now takes its arguments in the reverse order and
  3978   has acquired the infix notation "!" as in "xs!n".
  3979 
  3980 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  3981 
  3982 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  3983   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  3984 
  3985 * HOL/record: extensible records with schematic structural subtyping
  3986 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  3987 still lacks various theorems and concrete record syntax;
  3988 
  3989 
  3990 *** HOLCF ***
  3991 
  3992 * removed "axioms" and "generated by" sections;
  3993 
  3994 * replaced "ops" section by extended "consts" section, which is capable of
  3995   handling the continuous function space "->" directly;
  3996 
  3997 * domain package:
  3998   . proves theorems immediately and stores them in the theory,
  3999   . creates hierachical name space,
  4000   . now uses normal mixfix annotations (instead of cinfix...),
  4001   . minor changes to some names and values (for consistency),
  4002   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4003   . separator between mutual domain defs: changed "," to "and",
  4004   . improved handling of sort constraints;  now they have to
  4005     appear on the left-hand side of the equations only;
  4006 
  4007 * fixed LAM <x,y,zs>.b syntax;
  4008 
  4009 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4010 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4011 
  4012 
  4013 *** FOL and ZF ***
  4014 
  4015 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4016   with `addloop' of the simplifier to faciliate case splitting in premises.
  4017 
  4018 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4019 in HOL, they strip ALL and --> from proved theorems;
  4020 
  4021 
  4022 
  4023 New in Isabelle94-8 (May 1997)
  4024 ------------------------------
  4025 
  4026 *** General Changes ***
  4027 
  4028 * new utilities to build / run / maintain Isabelle etc. (in parts
  4029 still somewhat experimental); old Makefiles etc. still functional;
  4030 
  4031 * new 'Isabelle System Manual';
  4032 
  4033 * INSTALL text, together with ./configure and ./build scripts;
  4034 
  4035 * reimplemented type inference for greater efficiency, better error
  4036 messages and clean internal interface;
  4037 
  4038 * prlim command for dealing with lots of subgoals (an easier way of
  4039 setting goals_limit);
  4040 
  4041 
  4042 *** Syntax ***
  4043 
  4044 * supports alternative (named) syntax tables (parser and pretty
  4045 printer); internal interface is provided by add_modesyntax(_i);
  4046 
  4047 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4048 be used in conjunction with the Isabelle symbol font; uses the
  4049 "symbols" syntax table;
  4050 
  4051 * added token_translation interface (may translate name tokens in
  4052 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4053 the current print_mode); IMPORTANT: user print translation functions
  4054 are responsible for marking newly introduced bounds
  4055 (Syntax.mark_boundT);
  4056 
  4057 * token translations for modes "xterm" and "xterm_color" that display
  4058 names in bold, underline etc. or colors (which requires a color
  4059 version of xterm);
  4060 
  4061 * infixes may now be declared with names independent of their syntax;
  4062 
  4063 * added typed_print_translation (like print_translation, but may
  4064 access type of constant);
  4065 
  4066 
  4067 *** Classical Reasoner ***
  4068 
  4069 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4070 some limitations.  Blast_tac...
  4071   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4072   + ignores elimination rules that don't have the correct format
  4073         (the conclusion MUST be a formula variable)
  4074   + ignores types, which can make HOL proofs fail
  4075   + rules must not require higher-order unification, e.g. apply_type in ZF
  4076     [message "Function Var's argument not a bound variable" relates to this]
  4077   + its proof strategy is more general but can actually be slower
  4078 
  4079 * substitution with equality assumptions no longer permutes other
  4080 assumptions;
  4081 
  4082 * minor changes in semantics of addafter (now called addaltern); renamed
  4083 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4084 (and access functions for it);
  4085 
  4086 * improved combination of classical reasoner and simplifier:
  4087   + functions for handling clasimpsets
  4088   + improvement of addss: now the simplifier is called _after_ the
  4089     safe steps.
  4090   + safe variant of addss called addSss: uses safe simplifications
  4091     _during_ the safe steps. It is more complete as it allows multiple
  4092     instantiations of unknowns (e.g. with slow_tac).
  4093 
  4094 *** Simplifier ***
  4095 
  4096 * added interface for simplification procedures (functions that
  4097 produce *proven* rewrite rules on the fly, depending on current
  4098 redex);
  4099 
  4100 * ordering on terms as parameter (used for ordered rewriting);
  4101 
  4102 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4103 
  4104 * the solver is now split into a safe and an unsafe part.
  4105 This should be invisible for the normal user, except that the
  4106 functions setsolver and addsolver have been renamed to setSolver and
  4107 addSolver; added safe_asm_full_simp_tac;
  4108 
  4109 
  4110 *** HOL ***
  4111 
  4112 * a generic induction tactic `induct_tac' which works for all datatypes and
  4113 also for type `nat';
  4114 
  4115 * a generic case distinction tactic `exhaust_tac' which works for all
  4116 datatypes and also for type `nat';
  4117 
  4118 * each datatype comes with a function `size';
  4119 
  4120 * patterns in case expressions allow tuple patterns as arguments to
  4121 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4122 
  4123 * primrec now also works with type nat;
  4124 
  4125 * recdef: a new declaration form, allows general recursive functions to be
  4126 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4127 
  4128 * the constant for negation has been renamed from "not" to "Not" to
  4129 harmonize with FOL, ZF, LK, etc.;
  4130 
  4131 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4132 infinite lists;
  4133 
  4134 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4135 
  4136 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4137 problems in commutative rings, using axiomatic type classes for + and *;
  4138 
  4139 * more examples in HOL/MiniML and HOL/Auth;
  4140 
  4141 * more default rewrite rules for quantifiers, union/intersection;
  4142 
  4143 * a new constant `arbitrary == @x.False';
  4144 
  4145 * HOLCF/IOA replaces old HOL/IOA;
  4146 
  4147 * HOLCF changes: derived all rules and arities
  4148   + axiomatic type classes instead of classes
  4149   + typedef instead of faking type definitions
  4150   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4151   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4152   + eliminated the types void, one, tr
  4153   + use unit lift and bool lift (with translations) instead of one and tr
  4154   + eliminated blift from Lift3.thy (use Def instead of blift)
  4155   all eliminated rules are derived as theorems --> no visible changes ;
  4156 
  4157 
  4158 *** ZF ***
  4159 
  4160 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4161 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4162 as ZF_cs addSIs [equalityI];
  4163 
  4164 
  4165 
  4166 New in Isabelle94-7 (November 96)
  4167 ---------------------------------
  4168 
  4169 * allowing negative levels (as offsets) in prlev and choplev;
  4170 
  4171 * super-linear speedup for large simplifications;
  4172 
  4173 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4174 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4175 FAIL); can suppress it using the command Delsimps (ex_simps @
  4176 all_simps); De Morgan laws are also now included, by default;
  4177 
  4178 * improved printing of ==>  :  ~:
  4179 
  4180 * new object-logic "Sequents" adds linear logic, while replacing LK
  4181 and Modal (thanks to Sara Kalvala);
  4182 
  4183 * HOL/Auth: correctness proofs for authentication protocols;
  4184 
  4185 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4186 examples on HOL/Auth);
  4187 
  4188 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4189 the rewriter and classical reasoner simultaneously;
  4190 
  4191 * function uresult no longer returns theorems in "standard" format;
  4192 regain previous version by: val uresult = standard o uresult;
  4193 
  4194 
  4195 
  4196 New in Isabelle94-6
  4197 -------------------
  4198 
  4199 * oracles -- these establish an interface between Isabelle and trusted
  4200 external reasoners, which may deliver results as theorems;
  4201 
  4202 * proof objects (in particular record all uses of oracles);
  4203 
  4204 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4205 
  4206 * "constdefs" section in theory files;
  4207 
  4208 * "primrec" section (HOL) no longer requires names;
  4209 
  4210 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4211 
  4212 
  4213 
  4214 New in Isabelle94-5
  4215 -------------------
  4216 
  4217 * reduced space requirements;
  4218 
  4219 * automatic HTML generation from theories;
  4220 
  4221 * theory files no longer require "..." (quotes) around most types;
  4222 
  4223 * new examples, including two proofs of the Church-Rosser theorem;
  4224 
  4225 * non-curried (1994) version of HOL is no longer distributed;
  4226 
  4227 
  4228 
  4229 New in Isabelle94-4
  4230 -------------------
  4231 
  4232 * greatly reduced space requirements;
  4233 
  4234 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4235 
  4236 * searchable theorem database (see the section "Retrieving theorems" on
  4237 page 8 of the Reference Manual);
  4238 
  4239 * new examples, including Grabczewski's monumental case study of the
  4240 Axiom of Choice;
  4241 
  4242 * The previous version of HOL renamed to Old_HOL;
  4243 
  4244 * The new version of HOL (previously called CHOL) uses a curried syntax
  4245 for functions.  Application looks like f a b instead of f(a,b);
  4246 
  4247 * Mutually recursive inductive definitions finally work in HOL;
  4248 
  4249 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4250 translates to the operator "split";
  4251 
  4252 
  4253 
  4254 New in Isabelle94-3
  4255 -------------------
  4256 
  4257 * new infix operator, addss, allowing the classical reasoner to
  4258 perform simplification at each step of its search.  Example:
  4259         fast_tac (cs addss ss)
  4260 
  4261 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4262 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4263 look like (a,b) instead of <a,b>;
  4264 
  4265 * PLEASE NOTE: CHOL will eventually replace HOL!
  4266 
  4267 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4268 It translates to the operator "split".  A new theory of integers is available;
  4269 
  4270 * In ZF, integer numerals now denote two's-complement binary integers.
  4271 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4272 
  4273 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4274 of the Axiom of Choice;
  4275 
  4276 
  4277 
  4278 New in Isabelle94-2
  4279 -------------------
  4280 
  4281 * Significantly faster resolution;
  4282 
  4283 * the different sections in a .thy file can now be mixed and repeated
  4284 freely;
  4285 
  4286 * Database of theorems for FOL, HOL and ZF.  New
  4287 commands including qed, qed_goal and bind_thm store theorems in the database.
  4288 
  4289 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4290 a given theory (thms_of), or find out what theory a theorem was proved in
  4291 (theory_of_thm);
  4292 
  4293 * Bugs fixed in the inductive definition and datatype packages;
  4294 
  4295 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4296 and HOL_dup_cs obsolete;
  4297 
  4298 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4299 have been removed;
  4300 
  4301 * Simpler definition of function space in ZF;
  4302 
  4303 * new results about cardinal and ordinal arithmetic in ZF;
  4304 
  4305 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4306 types;
  4307 
  4308 
  4309 $Id$