NEWS
author schirmer
Wed Jul 05 11:32:38 2006 +0200 (2006-07-05)
changeset 20014 729a45534001
parent 20013 57505678692d
child 20040 02c59ec2f2e1
permissions -rw-r--r--
fixed let-simproc
----------------------------------------------------------------------
     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 * Command 'no_translations' removes translation rules from theory
    41 syntax.
    42 
    43 * Overloaded definitions are now actually checked for acyclic
    44 dependencies.  The overloading scheme is slightly more general than
    45 that of Haskell98, although Isabelle does not demand an exact
    46 correspondence to type class and instance declarations.
    47 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
    48 exotic versions of overloading -- at the discretion of the user!
    49 
    50 Polymorphic constants are represented via type arguments, i.e. the
    51 instantiation that matches an instance against the most general
    52 declaration given in the signature.  For example, with the declaration
    53 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
    54 as c(nat).  Overloading is essentially simultaneous structural
    55 recursion over such type arguments.  Incomplete specification patterns
    56 impose global constraints on all occurrences, e.g. c('a * 'a) on the
    57 LHS means that more general c('a * 'b) will be disallowed on any RHS.
    58 Command 'print_theory' outputs the normalized system of recursive
    59 equations, see section "definitions".
    60 
    61 * Isar: improper proof element 'guess' is like 'obtain', but derives
    62 the obtained context from the course of reasoning!  For example:
    63 
    64   assume "EX x y. A x & B y"   -- "any previous fact"
    65   then guess x and y by clarify
    66 
    67 This technique is potentially adventurous, depending on the facts and
    68 proof tools being involved here.
    69 
    70 * Isar: known facts from the proof context may be specified as literal
    71 propositions, using ASCII back-quote syntax.  This works wherever
    72 named facts used to be allowed so far, in proof commands, proof
    73 methods, attributes etc.  Literal facts are retrieved from the context
    74 according to unification of type and term parameters.  For example,
    75 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
    76 theorems in the current context, then these are valid literal facts:
    77 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
    78 
    79 There is also a proof method "fact" which does the same composition
    80 for explicit goal states, e.g. the following proof texts coincide with
    81 certain special cases of literal facts:
    82 
    83   have "A" by fact                 ==  note `A`
    84   have "A ==> B" by fact           ==  note `A ==> B`
    85   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
    86   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
    87 
    88 * Isar: 'print_facts' prints all local facts of the current context,
    89 both named and unnamed ones.
    90 
    91 * Isar: 'def' now admits simultaneous definitions, e.g.:
    92 
    93   def x == "t" and y == "u"
    94 
    95 * Isar: added command 'unfolding', which is structurally similar to
    96 'using', but affects both the goal state and facts by unfolding given
    97 rewrite rules.  Thus many occurrences of the 'unfold' method or
    98 'unfolded' attribute may be replaced by first-class proof text.
    99 
   100 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   101 and command 'unfolding' now all support object-level equalities
   102 (potentially conditional).  The underlying notion of rewrite rule is
   103 analogous to the 'rule_format' attribute, but *not* that of the
   104 Simplifier (which is usually more generous).
   105 
   106 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   107 method expression within a sandbox consisting of the first N
   108 sub-goals, which need to exist.  For example, ``simp_all [3]''
   109 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   110 simplifies all new goals that emerge from applying rule foo to the
   111 originally first one.
   112 
   113 * Isar: schematic goals are no longer restricted to higher-order
   114 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   115 expected.
   116 
   117 * Isar: the conclusion of a long theorem statement is now either
   118 'shows' (a simultaneous conjunction, as before), or 'obtains'
   119 (essentially a disjunction of cases with local parameters and
   120 assumptions).  The latter allows to express general elimination rules
   121 adequately; in this notation common elimination rules look like this:
   122 
   123   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   124     assumes "EX x. P x"
   125     obtains x where "P x"
   126 
   127   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   128     assumes "A & B"
   129     obtains A and B
   130 
   131   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   132     assumes "A | B"
   133     obtains
   134       A
   135     | B
   136 
   137 The subsequent classical rules even refer to the formal "thesis"
   138 explicitly:
   139 
   140   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   141     obtains "~ thesis"
   142 
   143   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   144     obtains "thesis ==> something"
   145 
   146 The actual proof of an 'obtains' statement is analogous to that of the
   147 Isar proof element 'obtain', only that there may be several cases.
   148 Optional case names may be specified in parentheses; these will be
   149 available both in the present proof and as annotations in the
   150 resulting rule, for later use with the 'cases' method (cf. attribute
   151 case_names).
   152 
   153 * Isar: 'print_statement' prints theorems from the current theory or
   154 proof context in long statement form, according to the syntax of a
   155 top-level lemma.
   156 
   157 * Isar: 'obtain' takes an optional case name for the local context
   158 introduction rule (default "that").
   159 
   160 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   161 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   162 to occur.
   163 
   164 * Pure: syntax "CONST name" produces a fully internalized constant
   165 according to the current context.  This is particularly useful for
   166 syntax translations that should refer to internal constant
   167 representations independently of name spaces.
   168 
   169 * Isar/locales: 'const_syntax' provides a robust interface to the
   170 'syntax' primitive that also works in a locale context.  Type
   171 declaration and internal syntactic representation of given constants
   172 retrieved from the context.
   173 
   174 * Isar/locales: new derived specification elements 'axiomatization',
   175 'definition', 'abbreviation', which support type-inference, admit
   176 object-level specifications (equality, equivalence).  See also the
   177 isar-ref manual.  Examples:
   178 
   179   axiomatization
   180     eq  (infix "===" 50)
   181     where eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   182 
   183   definition
   184     "f x y = x + y + 1"
   185     "g x = f x x"
   186 
   187   abbreviation
   188     neq  (infix "=!=" 50)
   189     "x =!= y == ~ (x === y)"
   190 
   191 These specifications may be also used in a locale context.  Then the
   192 constants being introduced depend on certain fixed parameters, and the
   193 constant name is qualified by the locale base name.  An internal
   194 abbreviation takes care for convenient input and output, making the
   195 parameters implicit and using the original short name.  See also
   196 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   197 entities from a monomorphic theory.
   198 
   199 Presently, abbreviations are only available 'in' a target locale, but
   200 not inherited by general import expressions.  Also note that
   201 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   202 'translations' in common applications.
   203 
   204 Concrete syntax is attached to specified constants in internal form,
   205 independently of name spaces.  The parse tree representation is
   206 slightly different -- use 'const_syntax' instead of raw 'syntax', and
   207 'translations' with explicit "CONST" markup to accommodate this.
   208 
   209 * Isar/locales: improved parameter handling:
   210 - use of locales "var" and "struct" no longer necessary;
   211 - parameter renamings are no longer required to be injective.
   212   This enables, for example, to define a locale for endomorphisms thus:
   213   locale endom = homom mult mult h.
   214 
   215 * Isar/locales: changed the way locales with predicates are defined.
   216 Instead of accumulating the specification, the imported expression is
   217 now an interpretation.
   218 INCOMPATIBILITY: different normal form of locale expressions.
   219 In particular, in interpretations of locales with predicates,
   220 goals repesenting already interpreted fragments are not removed
   221 automatically.  Use methods `intro_locales' and `unfold_locales'; see below.
   222 
   223 * Isar/locales: new methods `intro_locales' and `unfold_locales' provide
   224 backward reasoning on locales predicates.  The methods are aware of
   225 interpretations and discharge corresponding goals.  `intro_locales' is
   226 less aggressive then `unfold_locales' and does not unfold predicates to
   227 assumptions.
   228 
   229 * Isar/locales: the order in which locale fragments are accumulated
   230 has changed.  This enables to override declarations from fragments
   231 due to interpretations -- for example, unwanted simp rules.
   232 
   233 * Provers/induct: improved internal context management to support
   234 local fixes and defines on-the-fly.  Thus explicit meta-level
   235 connectives !! and ==> are rarely required anymore in inductive goals
   236 (using object-logic connectives for this purpose has been long
   237 obsolete anyway).  The subsequent proof patterns illustrate advanced
   238 techniques of natural induction; general datatypes and inductive sets
   239 work analogously (see also src/HOL/Lambda for realistic examples).
   240 
   241 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   242 parameters:
   243 
   244   lemma
   245     fixes n :: nat and x :: 'a
   246     assumes a: "A n x"
   247     shows "P n x"
   248     using a                     -- {* make induct insert fact a *}
   249   proof (induct n fixing: x)    -- {* generalize goal to "!!x. A n x ==> P n x" *}
   250     case 0
   251     show ?case sorry
   252   next
   253     case (Suc n)
   254     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   255     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   256     show ?case sorry
   257   qed
   258 
   259 (2) This is how to perform induction over ``expressions of a certain
   260 form'', using a locally defined inductive parameter n == "a x"
   261 together with strengthening (the latter is usually required to get
   262 sufficiently flexible induction hypotheses):
   263 
   264   lemma
   265     fixes a :: "'a => nat"
   266     assumes a: "A (a x)"
   267     shows "P (a x)"
   268     using a
   269   proof (induct n == "a x" fixing: x)
   270     ...
   271 
   272 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   273 particular technique.
   274 
   275 (3) This is how to perform existential reasoning ('obtains' or
   276 'obtain') by induction, while avoiding explicit object-logic
   277 encodings:
   278 
   279   lemma
   280     fixes n :: nat
   281     obtains x :: 'a where "P n x" and "Q n x"
   282   proof (induct n fixing: thesis)
   283     case 0
   284     obtain x where "P 0 x" and "Q 0 x" sorry
   285     then show thesis by (rule 0)
   286   next
   287     case (Suc n)
   288     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   289     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   290     then show thesis by (rule Suc.prems)
   291   qed
   292 
   293 Here the 'fixing: thesis' specification essentially modifies the scope
   294 of the formal thesis parameter, in order to the get the whole
   295 existence statement through the induction as expected.
   296 
   297 * Provers/induct: mutual induction rules are now specified as a list
   298 of rule sharing the same induction cases.  HOL packages usually
   299 provide foo_bar.inducts for mutually defined items foo and bar
   300 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   301 specify mutual induction rules differently, i.e. like this:
   302 
   303   (induct rule: foo_bar.inducts)
   304   (induct set: foo bar)
   305   (induct type: foo bar)
   306 
   307 The ML function ProjectRule.projections turns old-style rules into the
   308 new format.
   309 
   310 * Provers/induct: improved handling of simultaneous goals.  Instead of
   311 introducing object-level conjunction, the statement is now split into
   312 several conclusions, while the corresponding symbolic cases are
   313 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   314 explicitly.  For example:
   315 
   316   lemma
   317     fixes n :: nat
   318     shows "P n" and "Q n"
   319   proof (induct n)
   320     case 0 case 1
   321     show "P 0" sorry
   322   next
   323     case 0 case 2
   324     show "Q 0" sorry
   325   next
   326     case (Suc n) case 1
   327     note `P n` and `Q n`
   328     show "P (Suc n)" sorry
   329   next
   330     case (Suc n) case 2
   331     note `P n` and `Q n`
   332     show "Q (Suc n)" sorry
   333   qed
   334 
   335 The split into subcases may be deferred as follows -- this is
   336 particularly relevant for goal statements with local premises.
   337 
   338   lemma
   339     fixes n :: nat
   340     shows "A n ==> P n" and "B n ==> Q n"
   341   proof (induct n)
   342     case 0
   343     {
   344       case 1
   345       note `A 0`
   346       show "P 0" sorry
   347     next
   348       case 2
   349       note `B 0`
   350       show "Q 0" sorry
   351     }
   352   next
   353     case (Suc n)
   354     note `A n ==> P n` and `B n ==> Q n`
   355     {
   356       case 1
   357       note `A (Suc n)`
   358       show "P (Suc n)" sorry
   359     next
   360       case 2
   361       note `B (Suc n)`
   362       show "Q (Suc n)" sorry
   363     }
   364   qed
   365 
   366 If simultaneous goals are to be used with mutual rules, the statement
   367 needs to be structured carefully as a two-level conjunction, using
   368 lists of propositions separated by 'and':
   369 
   370   lemma
   371     shows "a : A ==> P1 a"
   372           "a : A ==> P2 a"
   373       and "b : B ==> Q1 b"
   374           "b : B ==> Q2 b"
   375           "b : B ==> Q3 b"
   376   proof (induct set: A B)
   377 
   378 * Provers/induct: support coinduction as well.  See
   379 src/HOL/Library/Coinductive_List.thy for various examples.
   380 
   381 * Simplifier: by default the simplifier trace only shows top level rewrites
   382 now. That is, trace_simp_depth_limit is set to 1 by default. Thus there is
   383 less danger of being flooded by the trace. The trace indicates where parts
   384 have been suppressed.
   385   
   386 * Provers/classical: removed obsolete classical version of elim_format
   387 attribute; classical elim/dest rules are now treated uniformly when
   388 manipulating the claset.
   389 
   390 * Provers/classical: stricter checks to ensure that supplied intro,
   391 dest and elim rules are well-formed; dest and elim rules must have at
   392 least one premise.
   393 
   394 * Provers/classical: attributes dest/elim/intro take an optional
   395 weight argument for the rule (just as the Pure versions).  Weights are
   396 ignored by automated tools, but determine the search order of single
   397 rule steps.
   398 
   399 * Syntax: input syntax now supports dummy variable binding "%_. b",
   400 where the body does not mention the bound variable.  Note that dummy
   401 patterns implicitly depend on their context of bounds, which makes
   402 "{_. _}" match any set comprehension as expected.  Potential
   403 INCOMPATIBILITY -- parse translations need to cope with syntactic
   404 constant "_idtdummy" in the binding position.
   405 
   406 * Syntax: removed obsolete syntactic constant "_K" and its associated
   407 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   408 for example "A -> B" => "Pi A (%_. B)".
   409 
   410 
   411 *** HOL ***
   412 
   413 * New top level command 'normal_form' computes the normal form of a term
   414 that may contain free variables. For example 'normal_form "rev[a,b,c]"'
   415 prints '[b,c,a]'. This command is suitable for heavy-duty computations
   416 because the functions are compiled to ML first.
   417 INCOMPATIBILITY: new keywords 'normal_form' must quoted when used as
   418 an identifier.
   419 
   420 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   421 25 like -->); output depends on the "iff" print_mode, the default is
   422 "A = B" (with priority 50).
   423 
   424 * Renamed constants in HOL.thy and Orderings.thy:
   425     op +   ~> HOL.plus
   426     op -   ~> HOL.minus
   427     uminus ~> HOL.uminus
   428     op *   ~> HOL.times
   429     op <   ~> Orderings.less
   430     op <=  ~> Orderings.less_eq
   431 
   432 Adaptions may be required in the following cases:
   433 
   434 a) User-defined constants using any of the names "plus", "minus", "times",
   435 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   436 may go wrong.
   437 INCOMPATIBILITY: use more specific names.
   438 
   439 b) Variables named "plus", "minus", "times", "less", "less_eq"
   440 INCOMPATIBILITY: use more specific names.
   441 
   442 c) Permutative equations (e.g. "a + b = b + a")
   443 Since the change of names also changes the order of terms, permutative
   444 rewrite rules may get applied in a different order. Experience shows that
   445 this is rarely the case (only two adaptions in the whole Isabelle
   446 distribution).
   447 INCOMPATIBILITY: rewrite proofs
   448 
   449 d) ML code directly refering to constant names
   450 This in general only affects hand-written proof tactics, simprocs and so on.
   451 INCOMPATIBILITY: grep your sourcecode and replace names.
   452 
   453 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   454 
   455 * The old set interval syntax "{m..n(}" (and relatives) has been removed.
   456   Use "{m..<n}" (and relatives) instead.
   457 
   458 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   459 "t = s" to False (by simproc "neq_simproc").  For backward
   460 compatibility this can be disabled by ML "reset use_neq_simproc".
   461 
   462 * "m dvd n" where m and n are numbers is evaluated to True/False by simp.
   463 
   464 * Theorem Cons_eq_map_conv no longer has attribute `simp'.
   465 
   466 * Theorem setsum_mult renamed to setsum_right_distrib.
   467 
   468 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   469 'rule' method.
   470 
   471 * Tactics 'sat' and 'satx' reimplemented, several improvements: goals
   472 no longer need to be stated as "<prems> ==> False", equivalences (i.e.
   473 "=" on type bool) are handled, variable names of the form "lit_<n>"
   474 are no longer reserved, significant speedup.
   475 
   476 * inductive and datatype: provide projections of mutual rules, bundled
   477 as foo_bar.inducts;
   478 
   479 * Library: theory Accessible_Part has been move to main HOL.
   480 
   481 * Library: added theory Coinductive_List of potentially infinite lists
   482 as greatest fixed-point.
   483 
   484 * Library: added theory AssocList which implements (finite) maps as
   485 association lists.
   486 
   487 * New proof method "evaluation" for efficiently solving a goal
   488   (i.e. a boolean expression) by compiling it to ML. The goal is
   489   "proved" (via the oracle "Evaluation") if it evaluates to True.
   490 
   491 
   492 *** HOL-Complex ***
   493 
   494 * Theory Real: new method ferrack implements quantifier elimination
   495 for linear arithmetic over the reals. The quantifier elimination
   496 feature is used only for decision, for compatibility with arith. This
   497 means a goal is either solved or left unchanged, no simplification.
   498 
   499 
   500 *** ML ***
   501 
   502 * Pure/library:
   503 
   504   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   505   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   506 
   507 The semantics of "burrow" is: "take a function with *simulatanously*
   508 transforms a list of value, and apply it *simulatanously* to a list of
   509 list of values of the appropriate type". Confer this with "map" which
   510 would *not* apply its argument function simulatanously but in
   511 sequence. "fold_burrow" has an additional context.
   512 
   513 Both actually avoid the usage of "unflat" since they hide away
   514 "unflat" from the user.
   515 
   516 * Pure/library: functions map2 and fold2 with curried syntax for
   517 simultanous mapping and folding:
   518 
   519     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   520     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   521 
   522 * Pure/library: indexed lists - some functions in the Isabelle library
   523 treating lists over 'a as finite mappings from [0...n] to 'a have been
   524 given more convenient names and signatures reminiscent of similar
   525 functions for alists, tables, etc:
   526 
   527   val nth: 'a list -> int -> 'a 
   528   val nth_update: int * 'a -> 'a list -> 'a list
   529   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   530   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   531 
   532 Note that fold_index starts counting at index 0, not 1 like foldln
   533 used to.
   534 
   535 * Pure/library: general ``divide_and_conquer'' combinator on lists.
   536 
   537 * Pure/General/name_mangler.ML provides a functor for generic name
   538 mangling (bijective mapping from any expression values to strings).
   539 
   540 * Pure/General/rat.ML implements rational numbers.
   541 
   542 * Pure/General/table.ML: the join operations now works via exceptions
   543 DUP/SAME instead of type option.  This is simpler in simple cases, and
   544 admits slightly more efficient complex applications.
   545 
   546 * Pure: datatype Context.generic joins theory/Proof.context and
   547 provides some facilities for code that works in either kind of
   548 context, notably GenericDataFun for uniform theory and proof data.
   549 
   550 * Pure: 'advanced' translation functions (parse_translation etc.) now
   551 use Context.generic instead of just theory.
   552 
   553 * Pure: simplified internal attribute type, which is now always
   554 Context.generic * thm -> Context.generic * thm.  Global (theory)
   555 vs. local (Proof.context) attributes have been discontinued, while
   556 minimizing code duplication.  Thm.rule_attribute and
   557 Thm.declaration_attribute build canonical attributes; see also
   558 structure Context for further operations on Context.generic, notably
   559 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   560 declarations and definitions.
   561 
   562 * Pure/kernel: consts certification ignores sort constraints given in
   563 signature declarations.  (This information is not relevant to the
   564 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE.
   565 
   566 * Pure: Logic.(un)varify only works in a global context, which is now
   567 enforced instead of silently assumed.  INCOMPATIBILITY, may use
   568 Logic.legacy_(un)varify as temporary workaround.
   569 
   570 * Pure: axiomatic type classes are now purely definitional, with
   571 explicit proofs of class axioms and super class relations performed
   572 internally.  See Pure/axclass.ML for the main internal interfaces --
   573 notably AxClass.define_class supercedes AxClass.add_axclass, and
   574 AxClass.axiomatize_class/classrel/arity supercede
   575 Sign.add_classes/classrel/arities.
   576 
   577 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
   578 global/local versions on theory vs. Proof.context have been
   579 discontinued; Attrib.syntax and Method.syntax have been adapted
   580 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
   581 attributes, methods, etc.
   582 
   583 * Pure: several functions of signature "... -> theory -> theory * ..."
   584 have been reoriented to "... -> theory -> ... * theory" in order to
   585 allow natural usage in combination with the ||>, ||>>, |-> and
   586 fold_map combinators.
   587 
   588 * Pure: primitive rule lift_rule now takes goal cterm instead of an
   589 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
   590 achieve the old behaviour.
   591 
   592 * Pure: the "Goal" constant is now called "prop", supporting a
   593 slightly more general idea of ``protecting'' meta-level rule
   594 statements.
   595 
   596 * Pure: structure Goal provides simple interfaces for
   597 init/conclude/finish and tactical prove operations (replacing former
   598 Tactic.prove).  Note that OldGoals.prove_goalw_cterm has long been
   599 obsolete, it is ill-behaved in a local proof context (e.g. with local
   600 fixes/assumes or in a locale context).
   601 
   602 * Isar: simplified treatment of user-level errors, using exception
   603 ERROR of string uniformly.  Function error now merely raises ERROR,
   604 without any side effect on output channels.  The Isar toplevel takes
   605 care of proper display of ERROR exceptions.  ML code may use plain
   606 handle/can/try; cat_error may be used to concatenate errors like this:
   607 
   608   ... handle ERROR msg => cat_error msg "..."
   609 
   610 Toplevel ML code (run directly or through the Isar toplevel) may be
   611 embedded into the Isar toplevel with exception display/debug like
   612 this:
   613 
   614   Isar.toplevel (fn () => ...)
   615 
   616 INCOMPATIBILITY, removed special transform_error facilities, removed
   617 obsolete variants of user-level exceptions (ERROR_MESSAGE,
   618 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
   619 -- use plain ERROR instead.
   620 
   621 * Isar: theory setup now has type (theory -> theory), instead of a
   622 list.  INCOMPATIBILITY, may use #> to compose setup functions.
   623 
   624 * Isar: installed ML toplevel pretty printer for type Proof.context,
   625 subject to ProofContext.debug/verbose flags.
   626 
   627 * Isar: Toplevel.theory_to_proof admits transactions that modify the
   628 theory before entering a proof state.  Transactions now always see a
   629 quasi-functional intermediate checkpoint, both in interactive and
   630 batch mode.
   631 
   632 * Simplifier: the simpset of a running simplification process now
   633 contains a proof context (cf. Simplifier.the_context), which is the
   634 very context that the initial simpset has been retrieved from (by
   635 simpset_of/local_simpset_of).  Consequently, all plug-in components
   636 (solver, looper etc.) may depend on arbitrary proof data.
   637 
   638 * Simplifier.inherit_context inherits the proof context (plus the
   639 local bounds) of the current simplification process; any simproc
   640 etc. that calls the Simplifier recursively should do this!  Removed
   641 former Simplifier.inherit_bounds, which is already included here --
   642 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
   643 specify an explicit context using Simplifier.context/theory_context.
   644 
   645 * Simplifier/Classical Reasoner: more abstract interfaces
   646 change_simpset/claset for modifying the simpset/claset reference of a
   647 theory; raw versions simpset/claset_ref etc. have been discontinued --
   648 INCOMPATIBILITY.
   649 
   650 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
   651 "Trueprop" etc.
   652 
   653 
   654 
   655 New in Isabelle2005 (October 2005)
   656 ----------------------------------
   657 
   658 *** General ***
   659 
   660 * Theory headers: the new header syntax for Isar theories is
   661 
   662   theory <name>
   663   imports <theory1> ... <theoryN>
   664   uses <file1> ... <fileM>
   665   begin
   666 
   667 where the 'uses' part is optional.  The previous syntax
   668 
   669   theory <name> = <theory1> + ... + <theoryN>:
   670 
   671 will disappear in the next release.  Use isatool fixheaders to convert
   672 existing theory files.  Note that there is no change in ancient
   673 non-Isar theories now, but these will disappear soon.
   674 
   675 * Theory loader: parent theories can now also be referred to via
   676 relative and absolute paths.
   677 
   678 * Command 'find_theorems' searches for a list of criteria instead of a
   679 list of constants. Known criteria are: intro, elim, dest, name:string,
   680 simp:term, and any term. Criteria can be preceded by '-' to select
   681 theorems that do not match. Intro, elim, dest select theorems that
   682 match the current goal, name:s selects theorems whose fully qualified
   683 name contain s, and simp:term selects all simplification rules whose
   684 lhs match term.  Any other term is interpreted as pattern and selects
   685 all theorems matching the pattern. Available in ProofGeneral under
   686 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
   687 
   688   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
   689 
   690 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   691 matching the current goal as introduction rule and not having "HOL."
   692 in their name (i.e. not being defined in theory HOL).
   693 
   694 * Command 'thms_containing' has been discontinued in favour of
   695 'find_theorems'; INCOMPATIBILITY.
   696 
   697 * Communication with Proof General is now 8bit clean, which means that
   698 Unicode text in UTF-8 encoding may be used within theory texts (both
   699 formal and informal parts).  Cf. option -U of the Isabelle Proof
   700 General interface.  Here are some simple examples (cf. src/HOL/ex):
   701 
   702   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
   703   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
   704 
   705 * Improved efficiency of the Simplifier and, to a lesser degree, the
   706 Classical Reasoner.  Typical big applications run around 2 times
   707 faster.
   708 
   709 
   710 *** Document preparation ***
   711 
   712 * Commands 'display_drafts' and 'print_drafts' perform simple output
   713 of raw sources.  Only those symbols that do not require additional
   714 LaTeX packages (depending on comments in isabellesym.sty) are
   715 displayed properly, everything else is left verbatim.  isatool display
   716 and isatool print are used as front ends (these are subject to the
   717 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
   718 
   719 * Command tags control specific markup of certain regions of text,
   720 notably folding and hiding.  Predefined tags include "theory" (for
   721 theory begin and end), "proof" for proof commands, and "ML" for
   722 commands involving ML code; the additional tags "visible" and
   723 "invisible" are unused by default.  Users may give explicit tag
   724 specifications in the text, e.g. ''by %invisible (auto)''.  The
   725 interpretation of tags is determined by the LaTeX job during document
   726 preparation: see option -V of isatool usedir, or options -n and -t of
   727 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
   728 \isadroptag.
   729 
   730 Several document versions may be produced at the same time via isatool
   731 usedir (the generated index.html will link all of them).  Typical
   732 specifications include ''-V document=theory,proof,ML'' to present
   733 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
   734 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
   735 these parts without any formal replacement text.  The Isabelle site
   736 default settings produce ''document'' and ''outline'' versions as
   737 specified above.
   738 
   739 * Several new antiquotations:
   740 
   741   @{term_type term} prints a term with its type annotated;
   742 
   743   @{typeof term} prints the type of a term;
   744 
   745   @{const const} is the same as @{term const}, but checks that the
   746   argument is a known logical constant;
   747 
   748   @{term_style style term} and @{thm_style style thm} print a term or
   749   theorem applying a "style" to it
   750 
   751   @{ML text}
   752 
   753 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
   754 definitions, equations, inequations etc., 'concl' printing only the
   755 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
   756 to print the specified premise.  TermStyle.add_style provides an ML
   757 interface for introducing further styles.  See also the "LaTeX Sugar"
   758 document practical applications.  The ML antiquotation prints
   759 type-checked ML expressions verbatim.
   760 
   761 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
   762 and 'text' support optional locale specification '(in loc)', which
   763 specifies the default context for interpreting antiquotations.  For
   764 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
   765 
   766 * Option 'locale=NAME' of antiquotations specifies an alternative
   767 context interpreting the subsequent argument.  For example: @{thm
   768 [locale=lattice] inf_assoc}.
   769 
   770 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
   771 a proof context.
   772 
   773 * Proper output of antiquotations for theory commands involving a
   774 proof context (such as 'locale' or 'theorem (in loc) ...').
   775 
   776 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
   777 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
   778 
   779 * isatool usedir: new option -C (default true) controls whether option
   780 -D should include a copy of the original document directory; -C false
   781 prevents unwanted effects such as copying of administrative CVS data.
   782 
   783 
   784 *** Pure ***
   785 
   786 * Considerably improved version of 'constdefs' command.  Now performs
   787 automatic type-inference of declared constants; additional support for
   788 local structure declarations (cf. locales and HOL records), see also
   789 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
   790 sequential dependencies of definitions within a single 'constdefs'
   791 section; moreover, the declared name needs to be an identifier.  If
   792 all fails, consider to fall back on 'consts' and 'defs' separately.
   793 
   794 * Improved indexed syntax and implicit structures.  First of all,
   795 indexed syntax provides a notational device for subscripted
   796 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
   797 expressions.  Secondly, in a local context with structure
   798 declarations, number indexes \<^sub>n or the empty index (default
   799 number 1) refer to a certain fixed variable implicitly; option
   800 show_structs controls printing of implicit structures.  Typical
   801 applications of these concepts involve record types and locales.
   802 
   803 * New command 'no_syntax' removes grammar declarations (and
   804 translations) resulting from the given syntax specification, which is
   805 interpreted in the same manner as for the 'syntax' command.
   806 
   807 * 'Advanced' translation functions (parse_translation etc.) may depend
   808 on the signature of the theory context being presently used for
   809 parsing/printing, see also isar-ref manual.
   810 
   811 * Improved 'oracle' command provides a type-safe interface to turn an
   812 ML expression of type theory -> T -> term into a primitive rule of
   813 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
   814 is already included here); see also FOL/ex/IffExample.thy;
   815 INCOMPATIBILITY.
   816 
   817 * axclass: name space prefix for class "c" is now "c_class" (was "c"
   818 before); "cI" is no longer bound, use "c.intro" instead.
   819 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
   820 axclasses vs. locales.
   821 
   822 * Improved internal renaming of symbolic identifiers -- attach primes
   823 instead of base 26 numbers.
   824 
   825 * New flag show_question_marks controls printing of leading question
   826 marks in schematic variable names.
   827 
   828 * In schematic variable names, *any* symbol following \<^isub> or
   829 \<^isup> is now treated as part of the base name.  For example, the
   830 following works without printing of awkward ".0" indexes:
   831 
   832   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   833     by simp
   834 
   835 * Inner syntax includes (*(*nested*) comments*).
   836 
   837 * Pretty printer now supports unbreakable blocks, specified in mixfix
   838 annotations as "(00...)".
   839 
   840 * Clear separation of logical types and nonterminals, where the latter
   841 may only occur in 'syntax' specifications or type abbreviations.
   842 Before that distinction was only partially implemented via type class
   843 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
   844 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
   845 exotic syntax specifications may require further adaption
   846 (e.g. Cube/Cube.thy).
   847 
   848 * Removed obsolete type class "logic", use the top sort {} instead.
   849 Note that non-logical types should be declared as 'nonterminals'
   850 rather than 'types'.  INCOMPATIBILITY for new object-logic
   851 specifications.
   852 
   853 * Attributes 'induct' and 'cases': type or set names may now be
   854 locally fixed variables as well.
   855 
   856 * Simplifier: can now control the depth to which conditional rewriting
   857 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
   858 Limit.
   859 
   860 * Simplifier: simplification procedures may now take the current
   861 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   862 interface), which is very useful for calling the Simplifier
   863 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
   864 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
   865 low-level mk_simproc no longer applies Logic.varify internally, to
   866 allow for use in a context of fixed variables.
   867 
   868 * thin_tac now works even if the assumption being deleted contains !!
   869 or ==>.  More generally, erule now works even if the major premise of
   870 the elimination rule contains !! or ==>.
   871 
   872 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
   873 
   874 * Reorganized bootstrapping of the Pure theories; CPure is now derived
   875 from Pure, which contains all common declarations already.  Both
   876 theories are defined via plain Isabelle/Isar .thy files.
   877 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   878 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
   879 use isatool fixcpure to adapt your theory and ML sources.
   880 
   881 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
   882 selections of theorems in named facts via index ranges.
   883 
   884 * 'print_theorems': in theory mode, really print the difference
   885 wrt. the last state (works for interactive theory development only),
   886 in proof mode print all local facts (cf. 'print_facts');
   887 
   888 * 'hide': option '(open)' hides only base names.
   889 
   890 * More efficient treatment of intermediate checkpoints in interactive
   891 theory development.
   892 
   893 * Code generator is now invoked via code_module (incremental code
   894 generation) and code_library (modular code generation, ML structures
   895 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
   896 must be quoted when used as identifiers.
   897 
   898 * New 'value' command for reading, evaluating and printing terms using
   899 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
   900 quoted when used as identifier.
   901 
   902 
   903 *** Locales ***
   904 
   905 * New commands for the interpretation of locale expressions in
   906 theories (1), locales (2) and proof contexts (3).  These generate
   907 proof obligations from the expression specification.  After the
   908 obligations have been discharged, theorems of the expression are added
   909 to the theory, target locale or proof context.  The synopsis of the
   910 commands is a follows:
   911 
   912   (1) interpretation expr inst
   913   (2) interpretation target < expr
   914   (3) interpret expr inst
   915 
   916 Interpretation in theories and proof contexts require a parameter
   917 instantiation of terms from the current context.  This is applied to
   918 specifications and theorems of the interpreted expression.
   919 Interpretation in locales only permits parameter renaming through the
   920 locale expression.  Interpretation is smart in that interpretations
   921 that are active already do not occur in proof obligations, neither are
   922 instantiated theorems stored in duplicate.  Use 'print_interps' to
   923 inspect active interpretations of a particular locale.  For details,
   924 see the Isar Reference manual.  Examples can be found in
   925 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
   926 
   927 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
   928 'interpret' instead.
   929 
   930 * New context element 'constrains' for adding type constraints to
   931 parameters.
   932 
   933 * Context expressions: renaming of parameters with syntax
   934 redeclaration.
   935 
   936 * Locale declaration: 'includes' disallowed.
   937 
   938 * Proper static binding of attribute syntax -- i.e. types / terms /
   939 facts mentioned as arguments are always those of the locale definition
   940 context, independently of the context of later invocations.  Moreover,
   941 locale operations (renaming and type / term instantiation) are applied
   942 to attribute arguments as expected.
   943 
   944 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
   945 actual attributes; rare situations may require Attrib.attribute to
   946 embed those attributes into Attrib.src that lack concrete syntax.
   947 Attribute implementations need to cooperate properly with the static
   948 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   949 Attrib.XXX_thm etc. already do the right thing without further
   950 intervention.  Only unusual applications -- such as "where" or "of"
   951 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
   952 on the context and the facts involved -- may have to assign parsed
   953 values to argument tokens explicitly.
   954 
   955 * Changed parameter management in theorem generation for long goal
   956 statements with 'includes'.  INCOMPATIBILITY: produces a different
   957 theorem statement in rare situations.
   958 
   959 * Locale inspection command 'print_locale' omits notes elements.  Use
   960 'print_locale!' to have them included in the output.
   961 
   962 
   963 *** Provers ***
   964 
   965 * Provers/hypsubst.ML: improved version of the subst method, for
   966 single-step rewriting: it now works in bound variable contexts. New is
   967 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
   968 rewrite a different subterm than the original subst method, which is
   969 still available as 'simplesubst'.
   970 
   971 * Provers/quasi.ML: new transitivity reasoners for transitivity only
   972 and quasi orders.
   973 
   974 * Provers/trancl.ML: new transitivity reasoner for transitive and
   975 reflexive-transitive closure of relations.
   976 
   977 * Provers/blast.ML: new reference depth_limit to make blast's depth
   978 limit (previously hard-coded with a value of 20) user-definable.
   979 
   980 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   981 is peformed already.  Object-logics merely need to finish their
   982 initial simpset configuration as before.  INCOMPATIBILITY.
   983 
   984 
   985 *** HOL ***
   986 
   987 * Symbolic syntax of Hilbert Choice Operator is now as follows:
   988 
   989   syntax (epsilon)
   990     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   991 
   992 The symbol \<some> is displayed as the alternative epsilon of LaTeX
   993 and x-symbol; use option '-m epsilon' to get it actually printed.
   994 Moreover, the mathematically important symbolic identifier \<epsilon>
   995 becomes available as variable, constant etc.  INCOMPATIBILITY,
   996 
   997 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   998 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   999 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1000 support corresponding Isar calculations.
  1001 
  1002 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1003 instead of ":".
  1004 
  1005 * theory SetInterval: changed the syntax for open intervals:
  1006 
  1007   Old       New
  1008   {..n(}    {..<n}
  1009   {)n..}    {n<..}
  1010   {m..n(}   {m..<n}
  1011   {)m..n}   {m<..n}
  1012   {)m..n(}  {m<..<n}
  1013 
  1014 The old syntax is still supported but will disappear in the next
  1015 release.  For conversion use the following Emacs search and replace
  1016 patterns (these are not perfect but work quite well):
  1017 
  1018   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1019   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1020 
  1021 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1022 equalities in commutative rings; method 'algebra' provides a generic
  1023 interface.
  1024 
  1025 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1026 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1027 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1028 be a tuple pattern.
  1029 
  1030 Some new syntax forms are available:
  1031 
  1032   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1033   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1034   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1035   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1036 
  1037 The latter form "\<Sum>x < k. e" used to be based on a separate
  1038 function "Summation", which has been discontinued.
  1039 
  1040 * theory Finite_Set: in structured induction proofs, the insert case
  1041 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1042 (insert F x)'.
  1043 
  1044 * The 'refute' command has been extended to support a much larger
  1045 fragment of HOL, including axiomatic type classes, constdefs and
  1046 typedefs, inductive datatypes and recursion.
  1047 
  1048 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1049 Requires zChaff with proof generation to be installed.  See
  1050 HOL/ex/SAT_Examples.thy for examples.
  1051 
  1052 * Datatype induction via method 'induct' now preserves the name of the
  1053 induction variable. For example, when proving P(xs::'a list) by
  1054 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1055 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1056 in unstructured proof scripts.
  1057 
  1058 * Reworked implementation of records.  Improved scalability for
  1059 records with many fields, avoiding performance problems for type
  1060 inference. Records are no longer composed of nested field types, but
  1061 of nested extension types. Therefore the record type only grows linear
  1062 in the number of extensions and not in the number of fields.  The
  1063 top-level (users) view on records is preserved.  Potential
  1064 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1065 old record representation. The type generated for a record is called
  1066 <record_name>_ext_type.
  1067 
  1068 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1069 proofs triggered by a record definition or a simproc (if
  1070 quick_and_dirty is enabled).  Definitions of large records can take
  1071 quite long.
  1072 
  1073 New simproc record_upd_simproc for simplification of multiple record
  1074 updates enabled by default.  Moreover, trivial updates are also
  1075 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1076 occasionally, since simplification is more powerful by default.
  1077 
  1078 * typedef: proper support for polymorphic sets, which contain extra
  1079 type-variables in the term.
  1080 
  1081 * Simplifier: automatically reasons about transitivity chains
  1082 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1083 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1084 old proofs break occasionally as simplification may now solve more
  1085 goals than previously.
  1086 
  1087 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1088 present.  Works for all partial orders (class "order"), in particular
  1089 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1090 just like y <= x.
  1091 
  1092 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1093 bound variable or a constant then the let is unfolded.  Otherwise
  1094 first a is simplified to b, and then f b is simplified to g. If
  1095 possible we abstract b from g arriving at "let x = b in h x",
  1096 otherwise we unfold the let and arrive at g.  The simproc can be
  1097 enabled/disabled by the reference use_let_simproc.  Potential
  1098 INCOMPATIBILITY since simplification is more powerful by default.
  1099 
  1100 * Classical reasoning: the meson method now accepts theorems as arguments.
  1101 
  1102 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1103 jobs to provide advice on the provability of subgoals.
  1104 
  1105 * Theory OrderedGroup and Ring_and_Field: various additions and
  1106 improvements to faciliate calculations involving equalities and
  1107 inequalities.
  1108 
  1109 The following theorems have been eliminated or modified
  1110 (INCOMPATIBILITY):
  1111 
  1112   abs_eq             now named abs_of_nonneg
  1113   abs_of_ge_0        now named abs_of_nonneg
  1114   abs_minus_eq       now named abs_of_nonpos
  1115   imp_abs_id         now named abs_of_nonneg
  1116   imp_abs_neg_id     now named abs_of_nonpos
  1117   mult_pos           now named mult_pos_pos
  1118   mult_pos_le        now named mult_nonneg_nonneg
  1119   mult_pos_neg_le    now named mult_nonneg_nonpos
  1120   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1121   mult_neg           now named mult_neg_neg
  1122   mult_neg_le        now named mult_nonpos_nonpos
  1123 
  1124 * Theory Parity: added rules for simplifying exponents.
  1125 
  1126 * Theory List:
  1127 
  1128 The following theorems have been eliminated or modified
  1129 (INCOMPATIBILITY):
  1130 
  1131   list_all_Nil       now named list_all.simps(1)
  1132   list_all_Cons      now named list_all.simps(2)
  1133   list_all_conv      now named list_all_iff
  1134   set_mem_eq         now named mem_iff
  1135 
  1136 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1137 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1138 
  1139 
  1140 *** HOL-Complex ***
  1141 
  1142 * Theory RealDef: better support for embedding natural numbers and
  1143 integers in the reals.
  1144 
  1145 The following theorems have been eliminated or modified
  1146 (INCOMPATIBILITY):
  1147 
  1148   exp_ge_add_one_self  now requires no hypotheses
  1149   real_of_int_add      reversed direction of equality (use [symmetric])
  1150   real_of_int_minus    reversed direction of equality (use [symmetric])
  1151   real_of_int_diff     reversed direction of equality (use [symmetric])
  1152   real_of_int_mult     reversed direction of equality (use [symmetric])
  1153 
  1154 * Theory RComplete: expanded support for floor and ceiling functions.
  1155 
  1156 * Theory Ln is new, with properties of the natural logarithm
  1157 
  1158 * Hyperreal: There is a new type constructor "star" for making
  1159 nonstandard types.  The old type names are now type synonyms:
  1160 
  1161   hypreal = real star
  1162   hypnat = nat star
  1163   hcomplex = complex star
  1164 
  1165 * Hyperreal: Many groups of similarly-defined constants have been
  1166 replaced by polymorphic versions (INCOMPATIBILITY):
  1167 
  1168   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1169 
  1170   starset      <-- starsetNat, starsetC
  1171   *s*          <-- *sNat*, *sc*
  1172   starset_n    <-- starsetNat_n, starsetC_n
  1173   *sn*         <-- *sNatn*, *scn*
  1174   InternalSets <-- InternalNatSets, InternalCSets
  1175 
  1176   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1177   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1178   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1179   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1180   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1181 
  1182 * Hyperreal: Many type-specific theorems have been removed in favor of
  1183 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1184 
  1185   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1186   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1187   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1188   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1189   right_minus <-- hypreal_add_minus
  1190   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1191   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1192   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1193   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1194   mult_1_right <-- hcomplex_mult_one_right
  1195   mult_zero_left <-- hcomplex_mult_zero_left
  1196   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1197   right_distrib <-- hypnat_add_mult_distrib2
  1198   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1199   right_inverse <-- hypreal_mult_inverse
  1200   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1201   order_refl <-- {hypreal,hypnat}_le_refl
  1202   order_trans <-- {hypreal,hypnat}_le_trans
  1203   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1204   order_less_le <-- {hypreal,hypnat}_less_le
  1205   linorder_linear <-- {hypreal,hypnat}_le_linear
  1206   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1207   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1208   add_nonneg_nonneg <-- hypreal_le_add_order
  1209 
  1210 * Hyperreal: Separate theorems having to do with type-specific
  1211 versions of constants have been merged into theorems that apply to the
  1212 new polymorphic constants (INCOMPATIBILITY):
  1213 
  1214   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1215   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1216   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1217   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1218   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1219   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1220   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1221   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1222   STAR_diff <-- {STAR,STARC}_diff
  1223   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1224     STARC_hcomplex_of_complex}_image_subset
  1225   starset_n_Un <-- starset{Nat,C}_n_Un
  1226   starset_n_Int <-- starset{Nat,C}_n_Int
  1227   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1228   starset_n_diff <-- starset{Nat,C}_n_diff
  1229   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1230   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1231   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1232   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1233   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1234   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1235   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1236   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1237   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1238   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1239   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1240   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1241   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1242   starfun_diff <-- starfun{C,RC,CR}_diff
  1243   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1244   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1245   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1246   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1247   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1248   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1249   starfun_Id <-- starfunC_Id
  1250   starfun_approx <-- starfun{Nat,CR}_approx
  1251   starfun_capprox <-- starfun{C,RC}_capprox
  1252   starfun_abs <-- starfunNat_rabs
  1253   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1254   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1255   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1256   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1257   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1258   starfun_add_approx <-- starfunCR_add_approx
  1259   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1260   starfun_divide <-- starfun{C,CR,RC}_divide
  1261   starfun_n <-- starfun{Nat,C}_n
  1262   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1263   starfun_n_add <-- starfun{Nat,C}_n_add
  1264   starfun_n_add_minus <-- starfunNat_n_add_minus
  1265   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1266   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1267   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1268 
  1269   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1270   star_n_minus <-- {hypreal,hcomplex}_minus
  1271   star_n_diff <-- {hypreal,hcomplex}_diff
  1272   star_n_mult <-- {hypreal,hcomplex}_mult
  1273   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1274   star_n_le <-- {hypreal,hypnat}_le
  1275   star_n_less <-- {hypreal,hypnat}_less
  1276   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1277   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1278   star_n_abs <-- hypreal_hrabs
  1279   star_n_divide <-- hcomplex_divide
  1280 
  1281   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1282   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1283   star_of_diff <-- hypreal_of_real_diff
  1284   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1285   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1286   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1287   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1288   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1289   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1290   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1291   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1292   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1293   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1294   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1295   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1296   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1297   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1298   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1299   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1300   star_of_power <-- hypreal_of_real_power
  1301   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1302 
  1303 * Hyperreal: new method "transfer" that implements the transfer
  1304 principle of nonstandard analysis. With a subgoal that mentions
  1305 nonstandard types like "'a star", the command "apply transfer"
  1306 replaces it with an equivalent one that mentions only standard types.
  1307 To be successful, all free variables must have standard types; non-
  1308 standard variables must have explicit universal quantifiers.
  1309 
  1310 * Hyperreal: A theory of Taylor series.
  1311 
  1312 
  1313 *** HOLCF ***
  1314 
  1315 * Discontinued special version of 'constdefs' (which used to support
  1316 continuous functions) in favor of the general Pure one with full
  1317 type-inference.
  1318 
  1319 * New simplification procedure for solving continuity conditions; it
  1320 is much faster on terms with many nested lambda abstractions (cubic
  1321 instead of exponential time).
  1322 
  1323 * New syntax for domain package: selector names are now optional.
  1324 Parentheses should be omitted unless argument is lazy, for example:
  1325 
  1326   domain 'a stream = cons "'a" (lazy "'a stream")
  1327 
  1328 * New command 'fixrec' for defining recursive functions with pattern
  1329 matching; defining multiple functions with mutual recursion is also
  1330 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1331 sinr, or any data constructor defined by the domain package. The given
  1332 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1333 syntax and examples.
  1334 
  1335 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1336 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1337 but the proof obligation additionally includes an admissibility
  1338 requirement. The packages generate instances of class cpo or pcpo,
  1339 with continuity and strictness theorems for Rep and Abs.
  1340 
  1341 * HOLCF: Many theorems have been renamed according to a more standard naming
  1342 scheme (INCOMPATIBILITY):
  1343 
  1344   foo_inject:  "foo$x = foo$y ==> x = y"
  1345   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1346   foo_less:    "(foo$x << foo$y) = (x << y)"
  1347   foo_strict:  "foo$UU = UU"
  1348   foo_defined: "... ==> foo$x ~= UU"
  1349   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1350 
  1351 
  1352 *** ZF ***
  1353 
  1354 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1355 including the First Isomorphism Theorem (on quotienting by the kernel
  1356 of a homomorphism).
  1357 
  1358 * ZF/Simplifier: install second copy of type solver that actually
  1359 makes use of TC rules declared to Isar proof contexts (or locales);
  1360 the old version is still required for ML proof scripts.
  1361 
  1362 
  1363 *** Cube ***
  1364 
  1365 * Converted to Isar theory format; use locales instead of axiomatic
  1366 theories.
  1367 
  1368 
  1369 *** ML ***
  1370 
  1371 * Pure/library.ML no longer defines its own option datatype, but uses
  1372 that of the SML basis, which has constructors NONE and SOME instead of
  1373 None and Some, as well as exception Option.Option instead of OPTION.
  1374 The functions the, if_none, is_some, is_none have been adapted
  1375 accordingly, while Option.map replaces apsome.
  1376 
  1377 * Pure/library.ML: the exception LIST has been given up in favour of
  1378 the standard exceptions Empty and Subscript, as well as
  1379 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1380 superceded by the standard hd and tl functions etc.
  1381 
  1382 A number of basic list functions are no longer exported to the ML
  1383 toplevel, as they are variants of predefined functions.  The following
  1384 suggests how one can translate existing code:
  1385 
  1386     rev_append xs ys = List.revAppend (xs, ys)
  1387     nth_elem (i, xs) = List.nth (xs, i)
  1388     last_elem xs = List.last xs
  1389     flat xss = List.concat xss
  1390     seq fs = List.app fs
  1391     partition P xs = List.partition P xs
  1392     mapfilter f xs = List.mapPartial f xs
  1393 
  1394 * Pure/library.ML: several combinators for linear functional
  1395 transformations, notably reverse application and composition:
  1396 
  1397   x |> f                f #> g
  1398   (x, y) |-> f          f #-> g
  1399 
  1400 * Pure/library.ML: introduced/changed precedence of infix operators:
  1401 
  1402   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1403   infix 2 ?;
  1404   infix 3 o oo ooo oooo;
  1405   infix 4 ~~ upto downto;
  1406 
  1407 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1408 infix operators.
  1409 
  1410 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1411 fold_map support linear functional transformations and nesting.  For
  1412 example:
  1413 
  1414   fold f [x1, ..., xN] y =
  1415     y |> f x1 |> ... |> f xN
  1416 
  1417   (fold o fold) f [xs1, ..., xsN] y =
  1418     y |> fold f xs1 |> ... |> fold f xsN
  1419 
  1420   fold f [x1, ..., xN] =
  1421     f x1 #> ... #> f xN
  1422 
  1423   (fold o fold) f [xs1, ..., xsN] =
  1424     fold f xs1 #> ... #> fold f xsN
  1425 
  1426 * Pure/library.ML: the following selectors on type 'a option are
  1427 available:
  1428 
  1429   the:               'a option -> 'a  (*partial*)
  1430   these:             'a option -> 'a  where 'a = 'b list
  1431   the_default: 'a -> 'a option -> 'a
  1432   the_list:          'a option -> 'a list
  1433 
  1434 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1435 basic operations for association lists, following natural argument
  1436 order; moreover the explicit equality predicate passed here avoids
  1437 potentially expensive polymorphic runtime equality checks.
  1438 The old functions may be expressed as follows:
  1439 
  1440   assoc = uncurry (AList.lookup (op =))
  1441   assocs = these oo AList.lookup (op =)
  1442   overwrite = uncurry (AList.update (op =)) o swap
  1443 
  1444 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1445 
  1446   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1447   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1448 
  1449 replacing make_keylist and keyfilter (occassionally used)
  1450 Naive rewrites:
  1451 
  1452   make_keylist = AList.make
  1453   keyfilter = AList.find (op =)
  1454 
  1455 * eq_fst and eq_snd now take explicit equality parameter, thus
  1456   avoiding eqtypes. Naive rewrites:
  1457 
  1458     eq_fst = eq_fst (op =)
  1459     eq_snd = eq_snd (op =)
  1460 
  1461 * Removed deprecated apl and apr (rarely used).
  1462   Naive rewrites:
  1463 
  1464     apl (n, op) =>>= curry op n
  1465     apr (op, m) =>>= fn n => op (n, m)
  1466 
  1467 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1468 provides a reasonably efficient light-weight implementation of sets as
  1469 lists.
  1470 
  1471 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1472 few new operations; existing lookup and update are now curried to
  1473 follow natural argument order (for use with fold etc.);
  1474 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1475 
  1476 * Pure/General: output via the Isabelle channels of
  1477 writeln/warning/error etc. is now passed through Output.output, with a
  1478 hook for arbitrary transformations depending on the print_mode
  1479 (cf. Output.add_mode -- the first active mode that provides a output
  1480 function wins).  Already formatted output may be embedded into further
  1481 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1482 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1483 accommodate easy composition of diagnostic messages etc.  Programmers
  1484 rarely need to care about Output.output or Output.raw at all, with
  1485 some notable exceptions: Output.output is required when bypassing the
  1486 standard channels (writeln etc.), or in token translations to produce
  1487 properly formatted results; Output.raw is required when capturing
  1488 already output material that will eventually be presented to the user
  1489 a second time.  For the default print mode, both Output.output and
  1490 Output.raw have no effect.
  1491 
  1492 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1493 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1494 cumulative results are displayed at the end of a batch session.
  1495 
  1496 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1497 replaced by File.platform_path and File.shell_path (with appropriate
  1498 hooks).  This provides a clean interface for unusual systems where the
  1499 internal and external process view of file names are different.
  1500 
  1501 * Pure: more efficient orders for basic syntactic entities: added
  1502 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1503 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1504 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1505 orders now -- potential INCOMPATIBILITY for code that depends on a
  1506 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1507 Library.sort_strings on result).
  1508 
  1509 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1510 fold_types traverse types/terms from left to right, observing natural
  1511 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1512 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1513 
  1514 * Pure: name spaces have been refined, with significant changes of the
  1515 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1516 to extern(_table).  The plain name entry path is superceded by a
  1517 general 'naming' context, which also includes the 'policy' to produce
  1518 a fully qualified name and external accesses of a fully qualified
  1519 name; NameSpace.extend is superceded by context dependent
  1520 Sign.declare_name.  Several theory and proof context operations modify
  1521 the naming context.  Especially note Theory.restore_naming and
  1522 ProofContext.restore_naming to get back to a sane state; note that
  1523 Theory.add_path is no longer sufficient to recover from
  1524 Theory.absolute_path in particular.
  1525 
  1526 * Pure: new flags short_names (default false) and unique_names
  1527 (default true) for controlling output of qualified names.  If
  1528 short_names is set, names are printed unqualified.  If unique_names is
  1529 reset, the name prefix is reduced to the minimum required to achieve
  1530 the original result when interning again, even if there is an overlap
  1531 with earlier declarations.
  1532 
  1533 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1534 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1535 (useful for printing error messages).  INCOMPATIBILITY.
  1536 
  1537 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1538 Theory.theory are now identified, referring to the universal
  1539 Context.theory (see Pure/context.ML).  Actual signature and theory
  1540 content is managed as theory data.  The old code and interfaces were
  1541 spread over many files and structures; the new arrangement introduces
  1542 considerable INCOMPATIBILITY to gain more clarity:
  1543 
  1544   Context -- theory management operations (name, identity, inclusion,
  1545     parents, ancestors, merge, etc.), plus generic theory data;
  1546 
  1547   Sign -- logical signature and syntax operations (declaring consts,
  1548     types, etc.), plus certify/read for common entities;
  1549 
  1550   Theory -- logical theory operations (stating axioms, definitions,
  1551     oracles), plus a copy of logical signature operations (consts,
  1552     types, etc.); also a few basic management operations (Theory.copy,
  1553     Theory.merge, etc.)
  1554 
  1555 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  1556 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  1557 for convenience -- they merely return the theory.
  1558 
  1559 * Pure: type Type.tsig is superceded by theory in most interfaces.
  1560 
  1561 * Pure: the Isar proof context type is already defined early in Pure
  1562 as Context.proof (note that ProofContext.context and Proof.context are
  1563 aliases, where the latter is the preferred name).  This enables other
  1564 Isabelle components to refer to that type even before Isar is present.
  1565 
  1566 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  1567 typeK, constK, axiomK, oracleK), but provide explicit operations for
  1568 any of these kinds.  For example, Sign.intern typeK is now
  1569 Sign.intern_type, Theory.hide_space Sign.typeK is now
  1570 Theory.hide_types.  Also note that former
  1571 Theory.hide_classes/types/consts are now
  1572 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  1573 internalize their arguments!  INCOMPATIBILITY.
  1574 
  1575 * Pure: get_thm interface (of PureThy and ProofContext) expects
  1576 datatype thmref (with constructors Name and NameSelection) instead of
  1577 plain string -- INCOMPATIBILITY;
  1578 
  1579 * Pure: cases produced by proof methods specify options, where NONE
  1580 means to remove case bindings -- INCOMPATIBILITY in
  1581 (RAW_)METHOD_CASES.
  1582 
  1583 * Pure: the following operations retrieve axioms or theorems from a
  1584 theory node or theory hierarchy, respectively:
  1585 
  1586   Theory.axioms_of: theory -> (string * term) list
  1587   Theory.all_axioms_of: theory -> (string * term) list
  1588   PureThy.thms_of: theory -> (string * thm) list
  1589   PureThy.all_thms_of: theory -> (string * thm) list
  1590 
  1591 * Pure: print_tac now outputs the goal through the trace channel.
  1592 
  1593 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  1594 Reference Toplevel.debug (default false) controls detailed printing
  1595 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  1596 controls execution profiling -- set to 1 for time and 2 for space
  1597 (both increase the runtime).
  1598 
  1599 * Isar session: The initial use of ROOT.ML is now always timed,
  1600 i.e. the log will show the actual process times, in contrast to the
  1601 elapsed wall-clock time that the outer shell wrapper produces.
  1602 
  1603 * Simplifier: improved handling of bound variables (nameless
  1604 representation, avoid allocating new strings).  Simprocs that invoke
  1605 the Simplifier recursively should use Simplifier.inherit_bounds to
  1606 avoid local name clashes.  Failure to do so produces warnings
  1607 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  1608 for further details.
  1609 
  1610 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  1611 bindings for all theorems stored within a given theory; this may help
  1612 in porting non-Isar theories to Isar ones, while keeping ML proof
  1613 scripts for the time being.
  1614 
  1615 * ML operator HTML.with_charset specifies the charset begin used for
  1616 generated HTML files.  For example:
  1617 
  1618   HTML.with_charset "utf-8" use_thy "Hebrew";
  1619   HTML.with_charset "utf-8" use_thy "Chinese";
  1620 
  1621 
  1622 *** System ***
  1623 
  1624 * Allow symlinks to all proper Isabelle executables (Isabelle,
  1625 isabelle, isatool etc.).
  1626 
  1627 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  1628 isatool doc, isatool mkdir, display_drafts etc.).
  1629 
  1630 * isatool usedir: option -f allows specification of the ML file to be
  1631 used by Isabelle; default is ROOT.ML.
  1632 
  1633 * New isatool version outputs the version identifier of the Isabelle
  1634 distribution being used.
  1635 
  1636 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1637 (containing Boolean satisfiability problems) into Isabelle/HOL
  1638 theories.
  1639 
  1640 
  1641 
  1642 New in Isabelle2004 (April 2004)
  1643 --------------------------------
  1644 
  1645 *** General ***
  1646 
  1647 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1648   Replaces linorder.ML.
  1649 
  1650 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1651   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1652   (\<a>...\<z>), are now considered normal letters, and can therefore
  1653   be used anywhere where an ASCII letter (a...zA...Z) has until
  1654   now. COMPATIBILITY: This obviously changes the parsing of some
  1655   terms, especially where a symbol has been used as a binder, say
  1656   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1657   as an identifier.  Fix it by inserting a space around former
  1658   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1659   existing theory and ML files.
  1660 
  1661 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  1662 
  1663 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  1664   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  1665   a normal (but invisible) letter. For multiple letter subscripts repeat
  1666   \<^isub> like this: x\<^isub>1\<^isub>2.
  1667 
  1668 * Pure: There are now sub-/superscripts that can span more than one
  1669   character. Text between \<^bsub> and \<^esub> is set in subscript in
  1670   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  1671   superscript. The new control characters are not identifier parts.
  1672 
  1673 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  1674   content of "..." to the latex file instead of \isacntrl... . The "..."
  1675   may consist of any printable characters excluding the end bracket >.
  1676 
  1677 * Pure: Using new Isar command "finalconsts" (or the ML functions
  1678   Theory.add_finals or Theory.add_finals_i) it is now possible to
  1679   declare constants "final", which prevents their being given a definition
  1680   later.  It is useful for constants whose behaviour is fixed axiomatically
  1681   rather than definitionally, such as the meta-logic connectives.
  1682 
  1683 * Pure: 'instance' now handles general arities with general sorts
  1684   (i.e. intersections of classes),
  1685 
  1686 * Presentation: generated HTML now uses a CSS style sheet to make layout
  1687   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  1688   It can be changed to alter the colors/layout of generated pages.
  1689 
  1690 
  1691 *** Isar ***
  1692 
  1693 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  1694   cut_tac, subgoal_tac and thin_tac:
  1695   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  1696     locales are no longer forced to write Isar proof scripts.
  1697     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  1698     emulations.
  1699   - INCOMPATIBILITY: names of variables to be instantiated may no
  1700     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  1701     This is consistent with the instantiation attribute "where".
  1702 
  1703 * Attributes "where" and "of":
  1704   - Now take type variables of instantiated theorem into account when reading
  1705     the instantiation string.  This fixes a bug that caused instantiated
  1706     theorems to have too special types in some circumstances.
  1707   - "where" permits explicit instantiations of type variables.
  1708 
  1709 * Calculation commands "moreover" and "also" no longer interfere with
  1710   current facts ("this"), admitting arbitrary combinations with "then"
  1711   and derived forms.
  1712 
  1713 * Locales:
  1714   - Goal statements involving the context element "includes" no longer
  1715     generate theorems with internal delta predicates (those ending on
  1716     "_axioms") in the premise.
  1717     Resolve particular premise with <locale>.intro to obtain old form.
  1718   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  1719     specification and "includes" elements in goal statement.
  1720   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  1721     [intro?] and [elim?] (respectively) by default.
  1722   - Experimental command for instantiation of locales in proof contexts:
  1723         instantiate <label>[<attrs>]: <loc>
  1724     Instantiates locale <loc> and adds all its theorems to the current context
  1725     taking into account their attributes.  Label and attrs are optional
  1726     modifiers, like in theorem declarations.  If present, names of
  1727     instantiated theorems are qualified with <label>, and the attributes
  1728     <attrs> are applied after any attributes these theorems might have already.
  1729       If the locale has assumptions, a chained fact of the form
  1730     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  1731     are derived.  The command does not support old-style locales declared
  1732     with "locale (open)".
  1733       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  1734 
  1735 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  1736   (Isar) contexts.
  1737 
  1738 
  1739 *** HOL ***
  1740 
  1741 * Proof import: new image HOL4 contains the imported library from
  1742   the HOL4 system with about 2500 theorems. It is imported by
  1743   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  1744   can be used like any other Isabelle image.  See
  1745   HOL/Import/HOL/README for more information.
  1746 
  1747 * Simplifier:
  1748   - Much improved handling of linear and partial orders.
  1749     Reasoners for linear and partial orders are set up for type classes
  1750     "linorder" and "order" respectively, and are added to the default simpset
  1751     as solvers.  This means that the simplifier can build transitivity chains
  1752     to solve goals from the assumptions.
  1753   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  1754     of blast or auto after simplification become unnecessary because the goal
  1755     is solved by simplification already.
  1756 
  1757 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  1758     all proved in axiomatic type classes for semirings, rings and fields.
  1759 
  1760 * Numerics:
  1761   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  1762     now formalized using the Ring_and_Field theory mentioned above.
  1763   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  1764     than before, because now they are set up once in a generic manner.
  1765   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  1766     Look for the general versions in Ring_and_Field (and Power if they concern
  1767     exponentiation).
  1768 
  1769 * Type "rat" of the rational numbers is now available in HOL-Complex.
  1770 
  1771 * Records:
  1772   - Record types are now by default printed with their type abbreviation
  1773     instead of the list of all field types. This can be configured via
  1774     the reference "print_record_type_abbr".
  1775   - Simproc "record_upd_simproc" for simplification of multiple updates added
  1776     (not enabled by default).
  1777   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  1778     EX x. x = sel r to True (not enabled by default).
  1779   - Tactic "record_split_simp_tac" to split and simplify records added.
  1780 
  1781 * 'specification' command added, allowing for definition by
  1782   specification.  There is also an 'ax_specification' command that
  1783   introduces the new constants axiomatically.
  1784 
  1785 * arith(_tac) is now able to generate counterexamples for reals as well.
  1786 
  1787 * HOL-Algebra: new locale "ring" for non-commutative rings.
  1788 
  1789 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  1790   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  1791 
  1792 * HOL-Matrix: a first theory for matrices in HOL with an application of
  1793   matrix theory to linear programming.
  1794 
  1795 * Unions and Intersections:
  1796   The latex output syntax of UN and INT has been changed
  1797   from "\Union x \in A. B" to "\Union_{x \in A} B"
  1798   i.e. the index formulae has become a subscript.
  1799   Similarly for "\Union x. B", and for \Inter instead of \Union.
  1800 
  1801 * Unions and Intersections over Intervals:
  1802   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  1803   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  1804   like in normal math, and corresponding versions for < and for intersection.
  1805 
  1806 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  1807   lexicographic dictonary ordering has been added as "lexord".
  1808 
  1809 * ML: the legacy theory structures Int and List have been removed. They had
  1810   conflicted with ML Basis Library structures having the same names.
  1811 
  1812 * 'refute' command added to search for (finite) countermodels.  Only works
  1813   for a fragment of HOL.  The installation of an external SAT solver is
  1814   highly recommended.  See "HOL/Refute.thy" for details.
  1815 
  1816 * 'quickcheck' command: Allows to find counterexamples by evaluating
  1817   formulae under an assignment of free variables to random values.
  1818   In contrast to 'refute', it can deal with inductive datatypes,
  1819   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  1820   for examples.
  1821 
  1822 
  1823 *** HOLCF ***
  1824 
  1825 * Streams now come with concatenation and are part of the HOLCF image
  1826 
  1827 
  1828 
  1829 New in Isabelle2003 (May 2003)
  1830 ------------------------------
  1831 
  1832 *** General ***
  1833 
  1834 * Provers/simplifier:
  1835 
  1836   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  1837     Assumptions are now subject to complete mutual simplification,
  1838     not just from left to right. The simplifier now preserves
  1839     the order of assumptions.
  1840 
  1841     Potential INCOMPATIBILITY:
  1842 
  1843     -- simp sometimes diverges where the old version did
  1844        not, e.g. invoking simp on the goal
  1845 
  1846         [| P (f x); y = x; f x = f y |] ==> Q
  1847 
  1848        now gives rise to the infinite reduction sequence
  1849 
  1850         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  1851 
  1852        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  1853        kind of problem.
  1854 
  1855     -- Tactics combining classical reasoner and simplification (such as auto)
  1856        are also affected by this change, because many of them rely on
  1857        simp. They may sometimes diverge as well or yield a different numbers
  1858        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  1859        in case of problems. Sometimes subsequent calls to the classical
  1860        reasoner will fail because a preceeding call to the simplifier too
  1861        eagerly simplified the goal, e.g. deleted redundant premises.
  1862 
  1863   - The simplifier trace now shows the names of the applied rewrite rules
  1864 
  1865   - You can limit the number of recursive invocations of the simplifier
  1866     during conditional rewriting (where the simplifie tries to solve the
  1867     conditions before applying the rewrite rule):
  1868     ML "simp_depth_limit := n"
  1869     where n is an integer. Thus you can force termination where previously
  1870     the simplifier would diverge.
  1871 
  1872   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  1873 
  1874   - No longer aborts on failed congruence proof.  Instead, the
  1875     congruence is ignored.
  1876 
  1877 * Pure: New generic framework for extracting programs from constructive
  1878   proofs. See HOL/Extraction.thy for an example instantiation, as well
  1879   as HOL/Extraction for some case studies.
  1880 
  1881 * Pure: The main goal of the proof state is no longer shown by default, only
  1882 the subgoals. This behaviour is controlled by a new flag.
  1883    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  1884 (ML: Proof.show_main_goal).
  1885 
  1886 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  1887 rules whose conclusion matches subgoal 1:
  1888       PG menu: Isabelle/Isar -> Show me -> matching rules
  1889 The rules are ordered by how closely they match the subgoal.
  1890 In particular, rules that solve a subgoal outright are displayed first
  1891 (or rather last, the way they are printed).
  1892 (ML: ProofGeneral.print_intros())
  1893 
  1894 * Pure: New flag trace_unify_fail causes unification to print
  1895 diagnostic information (PG: in trace buffer) when it fails. This is
  1896 useful for figuring out why single step proofs like rule, erule or
  1897 assumption failed.
  1898 
  1899 * Pure: Locale specifications now produce predicate definitions
  1900 according to the body of text (covering assumptions modulo local
  1901 definitions); predicate "loc_axioms" covers newly introduced text,
  1902 while "loc" is cumulative wrt. all included locale expressions; the
  1903 latter view is presented only on export into the global theory
  1904 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  1905 on the old view without predicates;
  1906 
  1907 * Pure: predefined locales "var" and "struct" are useful for sharing
  1908 parameters (as in CASL, for example); just specify something like
  1909 ``var x + var y + struct M'' as import;
  1910 
  1911 * Pure: improved thms_containing: proper indexing of facts instead of
  1912 raw theorems; check validity of results wrt. current name space;
  1913 include local facts of proof configuration (also covers active
  1914 locales), cover fixed variables in index; may use "_" in term
  1915 specification; an optional limit for the number of printed facts may
  1916 be given (the default is 40);
  1917 
  1918 * Pure: disallow duplicate fact bindings within new-style theory files
  1919 (batch-mode only);
  1920 
  1921 * Provers: improved induct method: assumptions introduced by case
  1922 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  1923 the goal statement); "foo" still refers to all facts collectively;
  1924 
  1925 * Provers: the function blast.overloaded has been removed: all constants
  1926 are regarded as potentially overloaded, which improves robustness in exchange
  1927 for slight decrease in efficiency;
  1928 
  1929 * Provers/linorder: New generic prover for transitivity reasoning over
  1930 linear orders.  Note: this prover is not efficient!
  1931 
  1932 * Isar: preview of problems to finish 'show' now produce an error
  1933 rather than just a warning (in interactive mode);
  1934 
  1935 
  1936 *** HOL ***
  1937 
  1938 * arith(_tac)
  1939 
  1940  - Produces a counter example if it cannot prove a goal.
  1941    Note that the counter example may be spurious if the goal is not a formula
  1942    of quantifier-free linear arithmetic.
  1943    In ProofGeneral the counter example appears in the trace buffer.
  1944 
  1945  - Knows about div k and mod k where k is a numeral of type nat or int.
  1946 
  1947  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  1948    linear arithmetic fails. This takes account of quantifiers and divisibility.
  1949    Presburger arithmetic can also be called explicitly via presburger(_tac).
  1950 
  1951 * simp's arithmetic capabilities have been enhanced a bit: it now
  1952 takes ~= in premises into account (by performing a case split);
  1953 
  1954 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  1955 are distributed over a sum of terms;
  1956 
  1957 * New tactic "trans_tac" and method "trans" instantiate
  1958 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  1959 "<=", "<" and "=").
  1960 
  1961 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  1962 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  1963 
  1964 * 'typedef' command has new option "open" to suppress the set
  1965 definition;
  1966 
  1967 * functions Min and Max on finite sets have been introduced (theory
  1968 Finite_Set);
  1969 
  1970 * attribute [symmetric] now works for relations as well; it turns
  1971 (x,y) : R^-1 into (y,x) : R, and vice versa;
  1972 
  1973 * induct over a !!-quantified statement (say !!x1..xn):
  1974   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  1975 
  1976 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  1977 %x. None. Warning: empty_def now refers to the previously hidden definition
  1978 of the empty set.
  1979 
  1980 * Algebra: formalization of classical algebra.  Intended as base for
  1981 any algebraic development in Isabelle.  Currently covers group theory
  1982 (up to Sylow's theorem) and ring theory (Universal Property of
  1983 Univariate Polynomials).  Contributions welcome;
  1984 
  1985 * GroupTheory: deleted, since its material has been moved to Algebra;
  1986 
  1987 * Complex: new directory of the complex numbers with numeric constants,
  1988 nonstandard complex numbers, and some complex analysis, standard and
  1989 nonstandard (Jacques Fleuriot);
  1990 
  1991 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  1992 
  1993 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  1994 Fleuriot);
  1995 
  1996 * Real/HahnBanach: updated and adapted to locales;
  1997 
  1998 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  1999 Gray and Kramer);
  2000 
  2001 * UNITY: added the Meier-Sanders theory of progress sets;
  2002 
  2003 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2004 as abstract algorithms, instantiated to the JVM;
  2005 
  2006 * Bali: Java source language formalization. Type system, operational
  2007 semantics, axiomatic semantics. Supported language features:
  2008 classes, interfaces, objects,virtual methods, static methods,
  2009 static/instance fields, arrays, access modifiers, definite
  2010 assignment, exceptions.
  2011 
  2012 
  2013 *** ZF ***
  2014 
  2015 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2016 universe, etc.);
  2017 
  2018 * Main ZF: virtually all theories converted to new-style format;
  2019 
  2020 
  2021 *** ML ***
  2022 
  2023 * Pure: Tactic.prove provides sane interface for internal proofs;
  2024 omits the infamous "standard" operation, so this is more appropriate
  2025 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2026 
  2027 * Pure: improved error reporting of simprocs;
  2028 
  2029 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2030 up simprocs;
  2031 
  2032 
  2033 *** Document preparation ***
  2034 
  2035 * uses \par instead of \\ for line breaks in theory text. This may
  2036 shift some page breaks in large documents. To get the old behaviour
  2037 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2038 
  2039 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2040 other packages
  2041 
  2042 * \<euro> now needs package babel/greek instead of marvosym (which
  2043 broke \Rightarrow)
  2044 
  2045 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2046 textcomp package)
  2047 
  2048 
  2049 
  2050 New in Isabelle2002 (March 2002)
  2051 --------------------------------
  2052 
  2053 *** Document preparation ***
  2054 
  2055 * greatly simplified document preparation setup, including more
  2056 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2057 instructive isatool mkdir; users should basically be able to get
  2058 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2059 users may run a separate document processing stage manually like this:
  2060 "isatool usedir -D output HOL Test && isatool document Test/output";
  2061 
  2062 * theory dependency graph may now be incorporated into documents;
  2063 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2064 with \includegraphics of LaTeX;
  2065 
  2066 * proper spacing of consecutive markup elements, especially text
  2067 blocks after section headings;
  2068 
  2069 * support bold style (for single symbols only), input syntax is like
  2070 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2071 
  2072 * \<bullet> is now output as bold \cdot by default, which looks much
  2073 better in printed text;
  2074 
  2075 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2076 note that these symbols are currently unavailable in Proof General /
  2077 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2078 
  2079 * isatool latex no longer depends on changed TEXINPUTS, instead
  2080 isatool document copies the Isabelle style files to the target
  2081 location;
  2082 
  2083 
  2084 *** Isar ***
  2085 
  2086 * Pure/Provers: improved proof by cases and induction;
  2087   - 'case' command admits impromptu naming of parameters (such as
  2088     "case (Suc n)");
  2089   - 'induct' method divinates rule instantiation from the inductive
  2090     claim; no longer requires excessive ?P bindings for proper
  2091     instantiation of cases;
  2092   - 'induct' method properly enumerates all possibilities of set/type
  2093     rules; as a consequence facts may be also passed through *type*
  2094     rules without further ado;
  2095   - 'induct' method now derives symbolic cases from the *rulified*
  2096     rule (before it used to rulify cases stemming from the internal
  2097     atomized version); this means that the context of a non-atomic
  2098     statement becomes is included in the hypothesis, avoiding the
  2099     slightly cumbersome show "PROP ?case" form;
  2100   - 'induct' may now use elim-style induction rules without chaining
  2101     facts, using ``missing'' premises from the goal state; this allows
  2102     rules stemming from inductive sets to be applied in unstructured
  2103     scripts, while still benefitting from proper handling of non-atomic
  2104     statements; NB: major inductive premises need to be put first, all
  2105     the rest of the goal is passed through the induction;
  2106   - 'induct' proper support for mutual induction involving non-atomic
  2107     rule statements (uses the new concept of simultaneous goals, see
  2108     below);
  2109   - append all possible rule selections, but only use the first
  2110     success (no backtracking);
  2111   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2112   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2113   - added 'print_induct_rules' (covered by help item in recent Proof
  2114     General versions);
  2115   - moved induct/cases attributes to Pure, methods to Provers;
  2116   - generic method setup instantiated for FOL and HOL;
  2117 
  2118 * Pure: support multiple simultaneous goal statements, for example
  2119 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2120 meta-level mechanism, this acts as if several individual goals had
  2121 been stated separately; in particular common proof methods need to be
  2122 repeated in order to cover all claims; note that a single elimination
  2123 step is *not* sufficient to establish the two conjunctions, so this
  2124 fails:
  2125 
  2126   assume "A & B" then have A and B ..   (*".." fails*)
  2127 
  2128 better use "obtain" in situations as above; alternative refer to
  2129 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2130 
  2131 * Pure: proper integration with ``locales''; unlike the original
  2132 version by Florian Kammller, Isar locales package high-level proof
  2133 contexts rather than raw logical ones (e.g. we admit to include
  2134 attributes everywhere); operations on locales include merge and
  2135 rename; support for implicit arguments (``structures''); simultaneous
  2136 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2137 some examples;
  2138 
  2139 * Pure: the following commands have been ``localized'', supporting a
  2140 target locale specification "(in name)": 'lemma', 'theorem',
  2141 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2142 stored both within the locale and at the theory level (exported and
  2143 qualified by the locale name);
  2144 
  2145 * Pure: theory goals may now be specified in ``long'' form, with
  2146 ad-hoc contexts consisting of arbitrary locale elements. for example
  2147 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2148 definitions may be given, too); the result is a meta-level rule with
  2149 the context elements being discharged in the obvious way;
  2150 
  2151 * Pure: new proof command 'using' allows to augment currently used
  2152 facts after a goal statement ('using' is syntactically analogous to
  2153 'apply', but acts on the goal's facts only); this allows chained facts
  2154 to be separated into parts given before and after a claim, as in
  2155 ``from a and b have C using d and e <proof>'';
  2156 
  2157 * Pure: renamed "antecedent" case to "rule_context";
  2158 
  2159 * Pure: new 'judgment' command records explicit information about the
  2160 object-logic embedding (used by several tools internally); no longer
  2161 use hard-wired "Trueprop";
  2162 
  2163 * Pure: added 'corollary' command;
  2164 
  2165 * Pure: fixed 'token_translation' command;
  2166 
  2167 * Pure: removed obsolete 'exported' attribute;
  2168 
  2169 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2170 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2171 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2172 
  2173 * Pure: method 'atomize' presents local goal premises as object-level
  2174 statements (atomic meta-level propositions); setup controlled via
  2175 rewrite rules declarations of 'atomize' attribute; example
  2176 application: 'induct' method with proper rule statements in improper
  2177 proof *scripts*;
  2178 
  2179 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2180 now consider the syntactic context of assumptions, giving a better
  2181 chance to get type-inference of the arguments right (this is
  2182 especially important for locales);
  2183 
  2184 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2185 mode;
  2186 
  2187 * Pure/obtain: the formal conclusion "thesis", being marked as
  2188 ``internal'', may no longer be reference directly in the text;
  2189 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2190 situations;
  2191 
  2192 * Pure: generic 'sym' attribute which declares a rule both as pure
  2193 'elim?' and for the 'symmetric' operation;
  2194 
  2195 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2196 text; the fixed correlation with particular command syntax has been
  2197 discontinued;
  2198 
  2199 * Pure: new method 'rules' is particularly well-suited for proof
  2200 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2201 but often produces more compact proof terms with less detours;
  2202 
  2203 * Pure/Provers/classical: simplified integration with pure rule
  2204 attributes and methods; the classical "intro?/elim?/dest?"
  2205 declarations coincide with the pure ones; the "rule" method no longer
  2206 includes classically swapped intros; "intro" and "elim" methods no
  2207 longer pick rules from the context; also got rid of ML declarations
  2208 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2209 INCOMPATIBILITY;
  2210 
  2211 * Provers/classical: attribute 'swapped' produces classical inversions
  2212 of introduction rules;
  2213 
  2214 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2215 rules instead of full simplifier context; 'iff' attribute handles
  2216 conditional rules;
  2217 
  2218 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2219 
  2220 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2221 "(permissive)" option to recover old behavior;
  2222 
  2223 * HOL: 'inductive' no longer features separate (collective) attributes
  2224 for 'intros' (was found too confusing);
  2225 
  2226 * HOL: properly declared induction rules less_induct and
  2227 wf_induct_rule;
  2228 
  2229 
  2230 *** HOL ***
  2231 
  2232 * HOL: moved over to sane numeral syntax; the new policy is as
  2233 follows:
  2234 
  2235   - 0 and 1 are polymorphic constants, which are defined on any
  2236   numeric type (nat, int, real etc.);
  2237 
  2238   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2239   binary representation internally;
  2240 
  2241   - type nat has special constructor Suc, and generally prefers Suc 0
  2242   over 1::nat and Suc (Suc 0) over 2::nat;
  2243 
  2244 This change may cause significant problems of INCOMPATIBILITY; here
  2245 are some hints on converting existing sources:
  2246 
  2247   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2248   entities, so expressions involving "-" (unary or binary minus) need
  2249   to be spaced properly;
  2250 
  2251   - existing occurrences of "1" may need to be constraint "1::nat" or
  2252   even replaced by Suc 0; similar for old "2";
  2253 
  2254   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2255 
  2256   - remove all special provisions on numerals in proofs;
  2257 
  2258 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2259 representation (depends on bin_arith_simps in the default context);
  2260 
  2261 * HOL: symbolic syntax for x^2 (numeral 2);
  2262 
  2263 * HOL: the class of all HOL types is now called "type" rather than
  2264 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2265 in axclass/classes, instance/arities, and (usually rare) occurrences
  2266 in typings (of consts etc.); internally the class is called
  2267 "HOL.type", ML programs should refer to HOLogic.typeS;
  2268 
  2269 * HOL/record package improvements:
  2270   - new derived operations "fields" to build a partial record section,
  2271     "extend" to promote a fixed record to a record scheme, and
  2272     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2273     declared as simp by default;
  2274   - shared operations ("more", "fields", etc.) now need to be always
  2275     qualified) --- potential INCOMPATIBILITY;
  2276   - removed "make_scheme" operations (use "make" with "extend") --
  2277     INCOMPATIBILITY;
  2278   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2279   - provides cases/induct rules for use with corresponding Isar
  2280     methods (for concrete records, record schemes, concrete more
  2281     parts, and schematic more parts -- in that order);
  2282   - internal definitions directly based on a light-weight abstract
  2283     theory of product types over typedef rather than datatype;
  2284 
  2285 * HOL: generic code generator for generating executable ML code from
  2286 specifications; specific support for HOL constructs such as inductive
  2287 datatypes and sets, as well as recursive functions; can be invoked
  2288 via 'generate_code' theory section;
  2289 
  2290 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2291 
  2292 * HOL: consolidated and renamed several theories.  In particular:
  2293         Ord.thy has been absorbed into HOL.thy
  2294         String.thy has been absorbed into List.thy
  2295 
  2296 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2297 (beware of argument permutation!);
  2298 
  2299 * HOL: linorder_less_split superseded by linorder_cases;
  2300 
  2301 * HOL/List: "nodups" renamed to "distinct";
  2302 
  2303 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2304 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2305   - Ex_def has changed, now need to use some_eq_ex
  2306 
  2307 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2308 in this (rare) case use:
  2309 
  2310   delSWrapper "split_all_tac"
  2311   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2312 
  2313 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2314 MAY FAIL;
  2315 
  2316 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2317 Isabelle's type classes, ^ on functions and relations has too general
  2318 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2319 necessary to attach explicit type constraints;
  2320 
  2321 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2322 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2323 renamed accordingly (eg "compI" -> "rel_compI").
  2324 
  2325 * HOL: syntax translations now work properly with numerals and records
  2326 expressions;
  2327 
  2328 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2329 of "lam" -- INCOMPATIBILITY;
  2330 
  2331 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2332 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2333 renamed "Product_Type.unit";
  2334 
  2335 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2336 
  2337 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2338 the "cases" method);
  2339 
  2340 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2341 Florian Kammller);
  2342 
  2343 * HOL/IMP: updated and converted to new-style theory format; several
  2344 parts turned into readable document, with proper Isar proof texts and
  2345 some explanations (by Gerwin Klein);
  2346 
  2347 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2348 
  2349 * HOL-Hyperreal is now a logic image;
  2350 
  2351 
  2352 *** HOLCF ***
  2353 
  2354 * Isar: consts/constdefs supports mixfix syntax for continuous
  2355 operations;
  2356 
  2357 * Isar: domain package adapted to new-style theory format, e.g. see
  2358 HOLCF/ex/Dnat.thy;
  2359 
  2360 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2361 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2362 lift.induct_tac, always use UU instead of Undef;
  2363 
  2364 * HOLCF/IMP: updated and converted to new-style theory;
  2365 
  2366 
  2367 *** ZF ***
  2368 
  2369 * Isar: proper integration of logic-specific tools and packages,
  2370 including theory commands '(co)inductive', '(co)datatype',
  2371 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2372 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2373 
  2374 * theory Main no longer includes AC; for the Axiom of Choice, base
  2375 your theory on Main_ZFC;
  2376 
  2377 * the integer library now covers quotients and remainders, with many
  2378 laws relating division to addition, multiplication, etc.;
  2379 
  2380 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2381 typeless version of the formalism;
  2382 
  2383 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2384 format;
  2385 
  2386 * ZF/Induct: new directory for examples of inductive definitions,
  2387 including theory Multiset for multiset orderings; converted to
  2388 new-style theory format;
  2389 
  2390 * ZF: many new theorems about lists, ordinals, etc.;
  2391 
  2392 
  2393 *** General ***
  2394 
  2395 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2396 variable proof controls level of detail: 0 = no proofs (only oracle
  2397 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2398 also ref manual for further ML interfaces;
  2399 
  2400 * Pure/axclass: removed obsolete ML interface
  2401 goal_subclass/goal_arity;
  2402 
  2403 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2404 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2405 separate tokens, so expressions involving minus need to be spaced
  2406 properly;
  2407 
  2408 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2409 rather than "infixl" or "infixr";
  2410 
  2411 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2412 sort constraint specifications in type inference; e.g. "x::_::foo"
  2413 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2414 type variable);
  2415 
  2416 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2417 control output of nested => (types); the default behavior is
  2418 "type_brackets";
  2419 
  2420 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2421 tokens into AST constants;
  2422 
  2423 * Pure/syntax: prefer later declarations of translations and print
  2424 translation functions; potential INCOMPATIBILITY: need to reverse
  2425 multiple declarations for same syntax element constant;
  2426 
  2427 * Pure/show_hyps reset by default (in accordance to existing Isar
  2428 practice);
  2429 
  2430 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2431 addSafter;
  2432 
  2433 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2434 as well;
  2435 
  2436 * system: tested support for MacOS X; should be able to get Isabelle +
  2437 Proof General to work in a plain Terminal after installing Poly/ML
  2438 (e.g. from the Isabelle distribution area) and GNU bash alone
  2439 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2440 support requires further installations, e.g. from
  2441 http://fink.sourceforge.net/);
  2442 
  2443 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2444 
  2445 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2446 of 40 MB), cf. ML_OPTIONS;
  2447 
  2448 * system: Proof General keywords specification is now part of the
  2449 Isabelle distribution (see etc/isar-keywords.el);
  2450 
  2451 * system: support for persistent Proof General sessions (refrain from
  2452 outdating all loaded theories on startup); user may create writable
  2453 logic images like this: ``isabelle -q HOL Test'';
  2454 
  2455 * system: smart selection of Isabelle process versus Isabelle
  2456 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2457 run both "isabelle" and "Isabelle" even if file names are badly
  2458 damaged (executable inspects the case of the first letter of its own
  2459 name); added separate "isabelle-process" and "isabelle-interface";
  2460 
  2461 * system: refrain from any attempt at filtering input streams; no
  2462 longer support ``8bit'' encoding of old isabelle font, instead proper
  2463 iso-latin characters may now be used; the related isatools
  2464 "symbolinput" and "nonascii" have disappeared as well;
  2465 
  2466 * system: removed old "xterm" interface (the print modes "xterm" and
  2467 "xterm_color" are still available for direct use in a suitable
  2468 terminal);
  2469 
  2470 
  2471 
  2472 New in Isabelle99-2 (February 2001)
  2473 -----------------------------------
  2474 
  2475 *** Overview of INCOMPATIBILITIES ***
  2476 
  2477 * HOL: please note that theories in the Library and elsewhere often use the
  2478 new-style (Isar) format; to refer to their theorems in an ML script you must
  2479 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2480 
  2481 * HOL: inductive package no longer splits induction rule aggressively,
  2482 but only as far as specified by the introductions given; the old
  2483 format may be recovered via ML function complete_split_rule or attribute
  2484 'split_rule (complete)';
  2485 
  2486 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2487 gfp_Tarski to gfp_unfold;
  2488 
  2489 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2490 
  2491 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2492 relation); infix "^^" has been renamed "``"; infix "``" has been
  2493 renamed "`"; "univalent" has been renamed "single_valued";
  2494 
  2495 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2496 operation;
  2497 
  2498 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2499 
  2500 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2501 
  2502 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2503 consequence, it is no longer monotonic wrt. the local goal context
  2504 (which is now passed through the inductive cases);
  2505 
  2506 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2507 \<gg> to \<ggreater>;
  2508 
  2509 
  2510 *** Document preparation ***
  2511 
  2512 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2513 available: are "it" for near math-mode best-style output, "sl" for
  2514 slanted text style, and "tt" for plain type-writer; if no
  2515 \isabellestyle command is given, output is according to slanted
  2516 type-writer);
  2517 
  2518 * support sub/super scripts (for single symbols only), input syntax is
  2519 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2520 
  2521 * some more standard symbols; see Appendix A of the system manual for
  2522 the complete list of symbols defined in isabellesym.sty;
  2523 
  2524 * improved isabelle style files; more abstract symbol implementation
  2525 (should now use \isamath{...} and \isatext{...} in custom symbol
  2526 definitions);
  2527 
  2528 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2529 state; Note that presentation of goal states does not conform to
  2530 actual human-readable proof documents.  Please do not include goal
  2531 states into document output unless you really know what you are doing!
  2532 
  2533 * proper indentation of antiquoted output with proportional LaTeX
  2534 fonts;
  2535 
  2536 * no_document ML operator temporarily disables LaTeX document
  2537 generation;
  2538 
  2539 * isatool unsymbolize tunes sources for plain ASCII communication;
  2540 
  2541 
  2542 *** Isar ***
  2543 
  2544 * Pure: Isar now suffers initial goal statements to contain unbound
  2545 schematic variables (this does not conform to actual readable proof
  2546 documents, due to unpredictable outcome and non-compositional proof
  2547 checking); users who know what they are doing may use schematic goals
  2548 for Prolog-style synthesis of proven results;
  2549 
  2550 * Pure: assumption method (an implicit finishing) now handles actual
  2551 rules as well;
  2552 
  2553 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  2554 initial goal, declare "that" only as Pure intro (only for single
  2555 steps); the "that" rule assumption may now be involved in implicit
  2556 finishing, thus ".." becomes a feasible for trivial obtains;
  2557 
  2558 * Pure: default proof step now includes 'intro_classes'; thus trivial
  2559 instance proofs may be performed by "..";
  2560 
  2561 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  2562 statements as well;
  2563 
  2564 * Pure: more robust selection of calculational rules;
  2565 
  2566 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  2567 rule (as well as the assumption rule);
  2568 
  2569 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  2570 lemmas, using the graph browser tool;
  2571 
  2572 * Pure: predict failure of "show" in interactive mode;
  2573 
  2574 * Pure: 'thms_containing' now takes actual terms as arguments;
  2575 
  2576 * HOL: improved method 'induct' --- now handles non-atomic goals
  2577 (potential INCOMPATIBILITY); tuned error handling;
  2578 
  2579 * HOL: cases and induct rules now provide explicit hints about the
  2580 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  2581 any remaining facts are inserted into the goal verbatim;
  2582 
  2583 * HOL: local contexts (aka cases) may now contain term bindings as
  2584 well; the 'cases' and 'induct' methods new provide a ?case binding for
  2585 the result to be shown in each case;
  2586 
  2587 * HOL: added 'recdef_tc' command;
  2588 
  2589 * isatool convert assists in eliminating legacy ML scripts;
  2590 
  2591 
  2592 *** HOL ***
  2593 
  2594 * HOL/Library: a collection of generic theories to be used together
  2595 with main HOL; the theory loader path already includes this directory
  2596 by default; the following existing theories have been moved here:
  2597 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  2598 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  2599 
  2600 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  2601 modelling and verification task performed in Isabelle/HOL +
  2602 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  2603 
  2604 * HOL/Algebra: special summation operator SUM no longer exists, it has
  2605 been replaced by setsum; infix 'assoc' now has priority 50 (like
  2606 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  2607 'domain', this makes the theory consistent with mathematical
  2608 literature;
  2609 
  2610 * HOL basics: added overloaded operations "inverse" and "divide"
  2611 (infix "/"), syntax for generic "abs" operation, generic summation
  2612 operator \<Sum>;
  2613 
  2614 * HOL/typedef: simplified package, provide more useful rules (see also
  2615 HOL/subset.thy);
  2616 
  2617 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  2618 now expressed as a proper nested rule (old-style tactic scripts may
  2619 require atomize_strip_tac to cope with non-atomic premises);
  2620 
  2621 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  2622 to "split_conv" (old name still available for compatibility);
  2623 
  2624 * HOL: improved concrete syntax for strings (e.g. allows translation
  2625 rules with string literals);
  2626 
  2627 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  2628  and Fleuriot's mechanization of analysis, including the transcendental
  2629  functions for the reals;
  2630 
  2631 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  2632 
  2633 
  2634 *** CTT ***
  2635 
  2636 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2637 "lam" is displayed as TWO lambda-symbols
  2638 
  2639 * CTT: theory Main now available, containing everything (that is, Bool
  2640 and Arith);
  2641 
  2642 
  2643 *** General ***
  2644 
  2645 * Pure: the Simplifier has been implemented properly as a derived rule
  2646 outside of the actual kernel (at last!); the overall performance
  2647 penalty in practical applications is about 50%, while reliability of
  2648 the Isabelle inference kernel has been greatly improved;
  2649 
  2650 * print modes "brackets" and "no_brackets" control output of nested =>
  2651 (types) and ==> (props); the default behaviour is "brackets";
  2652 
  2653 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2654 as assumptions as well;
  2655 
  2656 * system: support Poly/ML 4.0;
  2657 
  2658 * system: isatool install handles KDE version 1 or 2;
  2659 
  2660 
  2661 
  2662 New in Isabelle99-1 (October 2000)
  2663 ----------------------------------
  2664 
  2665 *** Overview of INCOMPATIBILITIES ***
  2666 
  2667 * HOL: simplification of natural numbers is much changed; to partly
  2668 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  2669 issue the following ML commands:
  2670 
  2671   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  2672   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  2673 
  2674 * HOL: simplification no longer dives into case-expressions; this is
  2675 controlled by "t.weak_case_cong" for each datatype t;
  2676 
  2677 * HOL: nat_less_induct renamed to less_induct;
  2678 
  2679 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  2680 fixsome to patch .thy and .ML sources automatically;
  2681 
  2682   select_equality  -> some_equality
  2683   select_eq_Ex     -> some_eq_ex
  2684   selectI2EX       -> someI2_ex
  2685   selectI2         -> someI2
  2686   selectI          -> someI
  2687   select1_equality -> some1_equality
  2688   Eps_sym_eq       -> some_sym_eq_trivial
  2689   Eps_eq           -> some_eq_trivial
  2690 
  2691 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  2692 
  2693 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  2694 instead);
  2695 
  2696 * HOL: the recursion equations generated by 'recdef' are now called
  2697 f.simps instead of f.rules;
  2698 
  2699 * HOL: qed_spec_mp now also handles bounded ALL as well;
  2700 
  2701 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  2702 sometimes be needed;
  2703 
  2704 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  2705 
  2706 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  2707 
  2708 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  2709 product is now "<*>" instead of "Times"; the lexicographic product is
  2710 now "<*lex*>" instead of "**";
  2711 
  2712 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  2713 of main HOL, but was unused); better use HOL's datatype package;
  2714 
  2715 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  2716 the old syntax may be recovered as follows:
  2717 
  2718   syntax (symbols)
  2719     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  2720       (infixl "\\<oplus>" 100)
  2721 
  2722 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2723 
  2724 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  2725 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  2726 internally;
  2727 
  2728 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  2729 changed from A/r to A//r;
  2730 
  2731 * ZF: new treatment of arithmetic (nat & int) may break some old
  2732 proofs;
  2733 
  2734 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  2735 rulify -> rule_format, elimify -> elim_format, ...);
  2736 
  2737 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2738 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  2739 should have to change intro!! to intro? only); replaced "delrule" by
  2740 "rule del";
  2741 
  2742 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  2743 
  2744 * Provers: strengthened force_tac by using new first_best_tac;
  2745 
  2746 * LaTeX document preparation: several changes of isabelle.sty (see
  2747 lib/texinputs);
  2748 
  2749 
  2750 *** Document preparation ***
  2751 
  2752 * formal comments (text blocks etc.) in new-style theories may now
  2753 contain antiquotations of thm/prop/term/typ/text to be presented
  2754 according to latex print mode; concrete syntax is like this:
  2755 @{term[show_types] "f(x) = a + x"};
  2756 
  2757 * isatool mkdir provides easy setup of Isabelle session directories,
  2758 including proper document sources;
  2759 
  2760 * generated LaTeX sources are now deleted after successful run
  2761 (isatool document -c); may retain a copy somewhere else via -D option
  2762 of isatool usedir;
  2763 
  2764 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  2765 style files, achieving self-contained LaTeX sources and simplifying
  2766 LaTeX debugging;
  2767 
  2768 * old-style theories now produce (crude) LaTeX output as well;
  2769 
  2770 * browser info session directories are now self-contained (may be put
  2771 on WWW server seperately); improved graphs of nested sessions; removed
  2772 graph for 'all sessions';
  2773 
  2774 * several improvements in isabelle style files; \isabellestyle{it}
  2775 produces fake math mode output; \isamarkupheader is now \section by
  2776 default; see lib/texinputs/isabelle.sty etc.;
  2777 
  2778 
  2779 *** Isar ***
  2780 
  2781 * Isar/Pure: local results and corresponding term bindings are now
  2782 subject to Hindley-Milner polymorphism (similar to ML); this
  2783 accommodates incremental type-inference very nicely;
  2784 
  2785 * Isar/Pure: new derived language element 'obtain' supports
  2786 generalized existence reasoning;
  2787 
  2788 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  2789 support accumulation of results, without applying any rules yet;
  2790 useful to collect intermediate results without explicit name
  2791 references, and for use with transitivity rules with more than 2
  2792 premises;
  2793 
  2794 * Isar/Pure: scalable support for case-analysis type proofs: new
  2795 'case' language element refers to local contexts symbolically, as
  2796 produced by certain proof methods; internally, case names are attached
  2797 to theorems as "tags";
  2798 
  2799 * Isar/Pure: theory command 'hide' removes declarations from
  2800 class/type/const name spaces;
  2801 
  2802 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  2803 indicate potential overloading;
  2804 
  2805 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  2806 
  2807 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  2808 "{a,b,c}" instead of {a,b,c};
  2809 
  2810 * Isar/Pure now provides its own version of intro/elim/dest
  2811 attributes; useful for building new logics, but beware of confusion
  2812 with the version in Provers/classical;
  2813 
  2814 * Isar/Pure: the local context of (non-atomic) goals is provided via
  2815 case name 'antecedent';
  2816 
  2817 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  2818 to the current context is now done automatically);
  2819 
  2820 * Isar/Pure: theory command 'method_setup' provides a simple interface
  2821 for definining proof methods in ML;
  2822 
  2823 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2824 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  2825 most cases, one should have to change intro!! to intro? only);
  2826 replaced "delrule" by "rule del";
  2827 
  2828 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  2829 'symmetric' attribute (the latter supercedes [RS sym]);
  2830 
  2831 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  2832 method modifier); 'simp' method: 'only:' modifier removes loopers as
  2833 well (including splits);
  2834 
  2835 * Isar/Provers: Simplifier and Classical methods now support all kind
  2836 of modifiers used in the past, including 'cong', 'iff', etc.
  2837 
  2838 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  2839 of Simplifier and Classical reasoner);
  2840 
  2841 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  2842 now support named cases; major packages (inductive, datatype, primrec,
  2843 recdef) support case names and properly name parameters;
  2844 
  2845 * Isar/HOL: new transitivity rules for substitution in inequalities --
  2846 monotonicity conditions are extracted to be proven at end of
  2847 calculations;
  2848 
  2849 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  2850 method anyway;
  2851 
  2852 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  2853 split_if split_if_asm; datatype package provides theorems foo.splits =
  2854 foo.split foo.split_asm for each datatype;
  2855 
  2856 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  2857 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  2858 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  2859 use "(cases (simplified))" method in proper proof texts);
  2860 
  2861 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  2862 
  2863 * Isar: names of theorems etc. may be natural numbers as well;
  2864 
  2865 * Isar: 'pr' command: optional arguments for goals_limit and
  2866 ProofContext.prems_limit; no longer prints theory contexts, but only
  2867 proof states;
  2868 
  2869 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  2870 additional print modes to be specified; e.g. "pr(latex)" will print
  2871 proof state according to the Isabelle LaTeX style;
  2872 
  2873 * Isar: improved support for emulating tactic scripts, including proof
  2874 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  2875 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  2876 (for HOL datatypes);
  2877 
  2878 * Isar: simplified (more robust) goal selection of proof methods: 1st
  2879 goal, all goals, or explicit goal specifier (tactic emulation); thus
  2880 'proof method scripts' have to be in depth-first order;
  2881 
  2882 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  2883 
  2884 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  2885 should instead use individual commands for printing items
  2886 (print_commands, print_methods etc.);
  2887 
  2888 * Isar: added 'nothing' --- the empty list of theorems;
  2889 
  2890 
  2891 *** HOL ***
  2892 
  2893 * HOL/MicroJava: formalization of a fragment of Java, together with a
  2894 corresponding virtual machine and a specification of its bytecode
  2895 verifier and a lightweight bytecode verifier, including proofs of
  2896 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  2897 Cornelia Pusch (see also the homepage of project Bali at
  2898 http://isabelle.in.tum.de/Bali/);
  2899 
  2900 * HOL/Algebra: new theory of rings and univariate polynomials, by
  2901 Clemens Ballarin;
  2902 
  2903 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  2904 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  2905 Rasmussen;
  2906 
  2907 * HOL/Lattice: fundamental concepts of lattice theory and order
  2908 structures, including duals, properties of bounds versus algebraic
  2909 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  2910 Theorem for complete lattices etc.; may also serve as a demonstration
  2911 for abstract algebraic reasoning using axiomatic type classes, and
  2912 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  2913 
  2914 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  2915 von Oheimb;
  2916 
  2917 * HOL/IMPP: extension of IMP with local variables and mutually
  2918 recursive procedures, by David von Oheimb;
  2919 
  2920 * HOL/Lambda: converted into new-style theory and document;
  2921 
  2922 * HOL/ex/Multiquote: example of multiple nested quotations and
  2923 anti-quotations -- basically a generalized version of de-Bruijn
  2924 representation; very useful in avoiding lifting of operations;
  2925 
  2926 * HOL/record: added general record equality rule to simpset; fixed
  2927 select-update simplification procedure to handle extended records as
  2928 well; admit "r" as field name;
  2929 
  2930 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  2931 other numeric types and also as the identity of groups, rings, etc.;
  2932 
  2933 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  2934 Types nat and int belong to this axclass;
  2935 
  2936 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  2937    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  2938    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  2939   two terms #m*u and #n*u are replaced by #(m+n)*u
  2940     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  2941   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  2942     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  2943 
  2944 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  2945 powerful prover for predicate logic but knows nothing of clasets; see
  2946 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  2947 
  2948 * HOL: new version of "case_tac" subsumes both boolean case split and
  2949 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  2950 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  2951 
  2952 * HOL: simplification no longer dives into case-expressions: only the
  2953 selector expression is simplified, but not the remaining arms; to
  2954 enable full simplification of case-expressions for datatype t, you may
  2955 remove t.weak_case_cong from the simpset, either globally (Delcongs
  2956 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  2957 
  2958 * HOL/recdef: the recursion equations generated by 'recdef' for
  2959 function 'f' are now called f.simps instead of f.rules; if all
  2960 termination conditions are proved automatically, these simplification
  2961 rules are added to the simpset, as in primrec; rules may be named
  2962 individually as well, resulting in a separate list of theorems for
  2963 each equation;
  2964 
  2965 * HOL/While is a new theory that provides a while-combinator. It
  2966 permits the definition of tail-recursive functions without the
  2967 provision of a termination measure. The latter is necessary once the
  2968 invariant proof rule for while is applied.
  2969 
  2970 * HOL: new (overloaded) notation for the set of elements below/above
  2971 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  2972 
  2973 * HOL: theorems impI, allI, ballI bound as "strip";
  2974 
  2975 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  2976 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  2977 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  2978 
  2979 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2980 
  2981 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  2982 main HOL, but was unused);
  2983 
  2984 * HOL: fewer consts declared as global (e.g. have to refer to
  2985 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  2986 
  2987 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  2988 in case of overlap with user translations (e.g. judgements over
  2989 tuples); (note that the underlying logical represenation is still
  2990 bogus);
  2991 
  2992 
  2993 *** ZF ***
  2994 
  2995 * ZF: simplification automatically cancels common terms in arithmetic
  2996 expressions over nat and int;
  2997 
  2998 * ZF: new treatment of nat to minimize type-checking: all operators
  2999 coerce their operands to a natural number using the function natify,
  3000 making the algebraic laws unconditional;
  3001 
  3002 * ZF: as above, for int: operators coerce their operands to an integer
  3003 using the function intify;
  3004 
  3005 * ZF: the integer library now contains many of the usual laws for the
  3006 orderings, including $<=, and monotonicity laws for $+ and $*;
  3007 
  3008 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3009 simplification;
  3010 
  3011 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3012 to the simplifier and classical reasoner simultaneously;
  3013 
  3014 
  3015 *** General ***
  3016 
  3017 * Provers: blast_tac now handles actual object-logic rules as
  3018 assumptions; note that auto_tac uses blast_tac internally as well;
  3019 
  3020 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3021 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3022 
  3023 * Provers: delrules now handles destruct rules as well (no longer need
  3024 explicit make_elim);
  3025 
  3026 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3027   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3028 use instead the strong form,
  3029   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3030 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3031 from destruct-rules;
  3032 
  3033 * Provers: Simplifier.easy_setup provides a fast path to basic
  3034 Simplifier setup for new object-logics;
  3035 
  3036 * Pure: AST translation rules no longer require constant head on LHS;
  3037 
  3038 * Pure: improved name spaces: ambiguous output is qualified; support
  3039 for hiding of names;
  3040 
  3041 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3042 XSYMBOL_HOME; no longer need to do manual configuration in most
  3043 situations;
  3044 
  3045 * system: compression of ML heaps images may now be controlled via -c
  3046 option of isabelle and isatool usedir (currently only observed by
  3047 Poly/ML);
  3048 
  3049 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3050 useful for remote X11);
  3051 
  3052 * system: provide TAGS file for Isabelle sources;
  3053 
  3054 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3055 order;
  3056 
  3057 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3058 timing flag supersedes proof_timing and Toplevel.trace;
  3059 
  3060 * ML: new combinators |>> and |>>> for incremental transformations
  3061 with secondary results (e.g. certain theory extensions):
  3062 
  3063 * ML: PureThy.add_defs gets additional argument to indicate potential
  3064 overloading (usually false);
  3065 
  3066 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3067 results;
  3068 
  3069 
  3070 
  3071 New in Isabelle99 (October 1999)
  3072 --------------------------------
  3073 
  3074 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3075 
  3076 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3077 are no longer simplified.  (This allows the simplifier to unfold recursive
  3078 functional programs.)  To restore the old behaviour, declare
  3079 
  3080     Delcongs [if_weak_cong];
  3081 
  3082 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3083 complement;
  3084 
  3085 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3086 
  3087 * HOL/datatype: mutual_induct_tac no longer exists --
  3088   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3089 
  3090 * HOL/typedef: fixed type inference for representing set; type
  3091 arguments now have to occur explicitly on the rhs as type constraints;
  3092 
  3093 * ZF: The con_defs part of an inductive definition may no longer refer
  3094 to constants declared in the same theory;
  3095 
  3096 * HOL, ZF: the function mk_cases, generated by the inductive
  3097 definition package, has lost an argument.  To simplify its result, it
  3098 uses the default simpset instead of a supplied list of theorems.
  3099 
  3100 * HOL/List: the constructors of type list are now Nil and Cons;
  3101 
  3102 * Simplifier: the type of the infix ML functions
  3103         setSSolver addSSolver setSolver addSolver
  3104 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3105 for packaging solvers. A solver is created via
  3106         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3107 where the string argument is only a comment.
  3108 
  3109 
  3110 *** Proof tools ***
  3111 
  3112 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3113 decision procedure for linear arithmetic. Currently it is used for
  3114 types `nat', `int', and `real' in HOL (see below); it can, should and
  3115 will be instantiated for other types and logics as well.
  3116 
  3117 * The simplifier now accepts rewrite rules with flexible heads, eg
  3118      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3119   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3120   matching.
  3121 
  3122 
  3123 *** General ***
  3124 
  3125 * New Isabelle/Isar subsystem provides an alternative to traditional
  3126 tactical theorem proving; together with the ProofGeneral/isar user
  3127 interface it offers an interactive environment for developing human
  3128 readable proof documents (Isar == Intelligible semi-automated
  3129 reasoning); for further information see isatool doc isar-ref,
  3130 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3131 
  3132 * improved and simplified presentation of theories: better HTML markup
  3133 (including colors), graph views in several sizes; isatool usedir now
  3134 provides a proper interface for user theories (via -P option); actual
  3135 document preparation based on (PDF)LaTeX is available as well (for
  3136 new-style theories only); see isatool doc system for more information;
  3137 
  3138 * native support for Proof General, both for classic Isabelle and
  3139 Isabelle/Isar;
  3140 
  3141 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3142 using the graph browser tool;
  3143 
  3144 * Isabelle manuals now also available as PDF;
  3145 
  3146 * theory loader rewritten from scratch (may not be fully
  3147 bug-compatible); old loadpath variable has been replaced by show_path,
  3148 add_path, del_path, reset_path functions; new operations such as
  3149 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3150 isatool doc ref);
  3151 
  3152 * improved isatool install: option -k creates KDE application icon,
  3153 option -p DIR installs standalone binaries;
  3154 
  3155 * added ML_PLATFORM setting (useful for cross-platform installations);
  3156 more robust handling of platform specific ML images for SML/NJ;
  3157 
  3158 * the settings environment is now statically scoped, i.e. it is never
  3159 created again in sub-processes invoked from isabelle, isatool, or
  3160 Isabelle;
  3161 
  3162 * path element specification '~~' refers to '$ISABELLE_HOME';
  3163 
  3164 * in locales, the "assumes" and "defines" parts may be omitted if
  3165 empty;
  3166 
  3167 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3168 long arrows);
  3169 
  3170 * new print_mode "HTML";
  3171 
  3172 * new flag show_tags controls display of tags of theorems (which are
  3173 basically just comments that may be attached by some tools);
  3174 
  3175 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3176 mode and goal output format:
  3177 
  3178 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3179 244c244
  3180 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3181 ---
  3182 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3183 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3184 181c181
  3185 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3186 ---
  3187 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3188 
  3189 * function bind_thms stores lists of theorems (cf. bind_thm);
  3190 
  3191 * new shorthand tactics ftac, eatac, datac, fatac;
  3192 
  3193 * qed (and friends) now accept "" as result name; in that case the
  3194 theorem is not stored, but proper checks and presentation of the
  3195 result still apply;
  3196 
  3197 * theorem database now also indexes constants "Trueprop", "all",
  3198 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3199 
  3200 
  3201 *** HOL ***
  3202 
  3203 ** HOL arithmetic **
  3204 
  3205 * There are now decision procedures for linear arithmetic over nat and
  3206 int:
  3207 
  3208 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3209 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3210 are treated as atomic; subformulae not involving type `nat' or `int'
  3211 are ignored; quantified subformulae are ignored unless they are
  3212 positive universal or negative existential. The tactic has to be
  3213 invoked by hand and can be a little bit slow. In particular, the
  3214 running time is exponential in the number of occurrences of `min' and
  3215 `max', and `-' on `nat'.
  3216 
  3217 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3218 (negated) (in)equalities among the premises and the conclusion into
  3219 account (i.e. no compound formulae) and does not know about `min' and
  3220 `max', and `-' on `nat'. It is fast and is used automatically by the
  3221 simplifier.
  3222 
  3223 NB: At the moment, these decision procedures do not cope with mixed
  3224 nat/int formulae where the two parts interact, such as `m < n ==>
  3225 int(m) < int(n)'.
  3226 
  3227 * HOL/Numeral provides a generic theory of numerals (encoded
  3228 efficiently as bit strings); setup for types nat/int/real is in place;
  3229 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3230 int, existing theories and proof scripts may require a few additional
  3231 type constraints;
  3232 
  3233 * integer division and remainder can now be performed on constant
  3234 arguments;
  3235 
  3236 * many properties of integer multiplication, division and remainder
  3237 are now available;
  3238 
  3239 * An interface to the Stanford Validity Checker (SVC) is available through the
  3240 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3241 are proved automatically.  SVC must be installed separately, and its results
  3242 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3243 invocation of the underlying oracle).  For SVC see
  3244   http://verify.stanford.edu/SVC
  3245 
  3246 * IsaMakefile: the HOL-Real target now builds an actual image;
  3247 
  3248 
  3249 ** HOL misc **
  3250 
  3251 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3252 (in Isabelle/Isar) -- by Gertrud Bauer;
  3253 
  3254 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3255 analysis for assembly languages with subtypes;
  3256 
  3257 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3258 -- avoids syntactic ambiguities and treats state, transition, and
  3259 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3260 changed syntax and (many) tactics;
  3261 
  3262 * HOL/inductive: Now also handles more general introduction rules such
  3263   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3264   theorems are now maintained within the theory (maintained via the
  3265   "mono" attribute);
  3266 
  3267 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3268   (using function types) such as
  3269 
  3270   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3271 
  3272 * HOL/record: record_simproc (part of the default simpset) takes care
  3273 of selectors applied to updated records; record_split_tac is no longer
  3274 part of the default claset; update_defs may now be removed from the
  3275 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3276 
  3277   claset_ref () := claset() addSWrapper record_split_wrapper;
  3278   Delsimprocs [record_simproc]
  3279 
  3280 * HOL/typedef: fixed type inference for representing set; type
  3281 arguments now have to occur explicitly on the rhs as type constraints;
  3282 
  3283 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3284 names rather than an ML expression;
  3285 
  3286 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3287 supplied later.  Program schemes can be defined, such as
  3288     "While B C s = (if B s then While B C (C s) else s)"
  3289 where the well-founded relation can be chosen after B and C have been given.
  3290 
  3291 * HOL/List: the constructors of type list are now Nil and Cons;
  3292 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3293 course, ML tools referring to List.list.op # etc. have to be adapted;
  3294 
  3295 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3296 disabled by default; run isabelle with option -m HOL to get back to
  3297 the original Gordon/HOL-style output;
  3298 
  3299 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3300 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3301 
  3302 * HOL basic syntax simplified (more orthogonal): all variants of
  3303 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3304 Eps operator is provided as well: "SOME x. P[x]";
  3305 
  3306 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3307 
  3308 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3309 thus available for user theories;
  3310 
  3311 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3312 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3313 time;
  3314 
  3315 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3316 several times and then mp;
  3317 
  3318 
  3319 *** LK ***
  3320 
  3321 * the notation <<...>> is now available as a notation for sequences of
  3322 formulas;
  3323 
  3324 * the simplifier is now installed
  3325 
  3326 * the axiom system has been generalized (thanks to Soren Heilmann)
  3327 
  3328 * the classical reasoner now has a default rule database
  3329 
  3330 
  3331 *** ZF ***
  3332 
  3333 * new primrec section allows primitive recursive functions to be given
  3334 directly (as in HOL) over datatypes and the natural numbers;
  3335 
  3336 * new tactics induct_tac and exhaust_tac for induction (or case
  3337 analysis) over datatypes and the natural numbers;
  3338 
  3339 * the datatype declaration of type T now defines the recursor T_rec;
  3340 
  3341 * simplification automatically does freeness reasoning for datatype
  3342 constructors;
  3343 
  3344 * automatic type-inference, with AddTCs command to insert new
  3345 type-checking rules;
  3346 
  3347 * datatype introduction rules are now added as Safe Introduction rules
  3348 to the claset;
  3349 
  3350 * the syntax "if P then x else y" is now available in addition to
  3351 if(P,x,y);
  3352 
  3353 
  3354 *** Internal programming interfaces ***
  3355 
  3356 * tuned simplifier trace output; new flag debug_simp;
  3357 
  3358 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3359 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3360 
  3361 * AxClass.axclass_tac lost the theory argument;
  3362 
  3363 * tuned current_goals_markers semantics: begin / end goal avoids
  3364 printing empty lines;
  3365 
  3366 * removed prs and prs_fn hook, which was broken because it did not
  3367 include \n in its semantics, forcing writeln to add one
  3368 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3369 string -> unit if you really want to output text without newline;
  3370 
  3371 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3372 plain output, interface builders may have to enable 'isabelle_font'
  3373 mode to get Isabelle font glyphs as before;
  3374 
  3375 * refined token_translation interface; INCOMPATIBILITY: output length
  3376 now of type real instead of int;
  3377 
  3378 * theory loader actions may be traced via new ThyInfo.add_hook
  3379 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3380 your own database of information attached to *whole* theories -- as
  3381 opposed to intra-theory data slots offered via TheoryDataFun;
  3382 
  3383 * proper handling of dangling sort hypotheses (at last!);
  3384 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3385 extra sort hypotheses that can be witnessed from the type signature;
  3386 the force_strip_shyps flag is gone, any remaining shyps are simply
  3387 left in the theorem (with a warning issued by strip_shyps_warning);
  3388 
  3389 
  3390 
  3391 New in Isabelle98-1 (October 1998)
  3392 ----------------------------------
  3393 
  3394 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3395 
  3396 * several changes of automated proof tools;
  3397 
  3398 * HOL: major changes to the inductive and datatype packages, including
  3399 some minor incompatibilities of theory syntax;
  3400 
  3401 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3402 called `inj_on';
  3403 
  3404 * HOL: removed duplicate thms in Arith:
  3405   less_imp_add_less  should be replaced by  trans_less_add1
  3406   le_imp_add_le      should be replaced by  trans_le_add1
  3407 
  3408 * HOL: unary minus is now overloaded (new type constraints may be
  3409 required);
  3410 
  3411 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3412 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3413 now taken as an integer constant.
  3414 
  3415 * Pure: ML function 'theory_of' renamed to 'theory';
  3416 
  3417 
  3418 *** Proof tools ***
  3419 
  3420 * Simplifier:
  3421   1. Asm_full_simp_tac is now more aggressive.
  3422      1. It will sometimes reorient premises if that increases their power to
  3423         simplify.
  3424      2. It does no longer proceed strictly from left to right but may also
  3425         rotate premises to achieve further simplification.
  3426      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3427      old Asm_full_simp_tac in that it does not rotate premises.
  3428   2. The simplifier now knows a little bit about nat-arithmetic.
  3429 
  3430 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3431 allows for selected deletion of wrappers, by introduction of names for
  3432 wrapper functionals.  This implies that addbefore, addSbefore,
  3433 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3434 and that adding two tactics with the same name overwrites the first
  3435 one (emitting a warning).
  3436   type wrapper = (int -> tactic) -> (int -> tactic)
  3437   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3438   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3439   delWrapper, delSWrapper: claset *  string            -> claset
  3440   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3441 
  3442 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3443 semantics; addbefore now affects only the unsafe part of step_tac
  3444 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3445 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3446 by Force_tac;
  3447 
  3448 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3449 compWrapper; added safe wrapper (and access functions for it);
  3450 
  3451 * HOL/split_all_tac is now much faster and fails if there is nothing
  3452 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3453 and the names of the automatically generated variables have changed.
  3454 split_all_tac has moved within claset() from unsafe wrappers to safe
  3455 wrappers, which means that !!-bound variables are split much more
  3456 aggressively, and safe_tac and clarify_tac now split such variables.
  3457 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3458 Note: the same holds for record_split_tac, which does the job of
  3459 split_all_tac for record fields.
  3460 
  3461 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3462 permanently to the default simpset using Addsplits just like
  3463 Addsimps. They can be removed via Delsplits just like
  3464 Delsimps. Lower-case versions are also available.
  3465 
  3466 * HOL/Simplifier: The rule split_if is now part of the default
  3467 simpset. This means that the simplifier will eliminate all occurrences
  3468 of if-then-else in the conclusion of a goal. To prevent this, you can
  3469 either remove split_if completely from the default simpset by
  3470 `Delsplits [split_if]' or remove it in a specific call of the
  3471 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3472 other case splitting rules to/from the default simpset: every datatype
  3473 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3474 t is the name of the datatype).
  3475 
  3476 * Classical reasoner / Simplifier combination: new force_tac (and
  3477 derivatives Force_tac, force) combines rewriting and classical
  3478 reasoning (and whatever other tools) similarly to auto_tac, but is
  3479 aimed to solve the given subgoal completely.
  3480 
  3481 
  3482 *** General ***
  3483 
  3484 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3485 and `goalw': the theory is no longer needed as an explicit argument -
  3486 the current theory context is used; assumptions are no longer returned
  3487 at the ML-level unless one of them starts with ==> or !!; it is
  3488 recommended to convert to these new commands using isatool fixgoal
  3489 (backup your sources first!);
  3490 
  3491 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3492 the current theory context, and 'theory' to lookup stored theories;
  3493 
  3494 * new theory section 'locale' for declaring constants, assumptions and
  3495 definitions that have local scope;
  3496 
  3497 * new theory section 'nonterminals' for purely syntactic types;
  3498 
  3499 * new theory section 'setup' for generic ML setup functions
  3500 (e.g. package initialization);
  3501 
  3502 * the distribution now includes Isabelle icons: see
  3503 lib/logo/isabelle-{small,tiny}.xpm;
  3504 
  3505 * isatool install - install binaries with absolute references to
  3506 ISABELLE_HOME/bin;
  3507 
  3508 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3509 
  3510 * print mode 'emacs' reserved for Isamode;
  3511 
  3512 * support multiple print (ast) translations per constant name;
  3513 
  3514 * theorems involving oracles are now printed with a suffixed [!];
  3515 
  3516 
  3517 *** HOL ***
  3518 
  3519 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3520 
  3521 * HOL/inductive package reorganized and improved: now supports mutual
  3522 definitions such as
  3523 
  3524   inductive EVEN ODD
  3525     intrs
  3526       null "0 : EVEN"
  3527       oddI "n : EVEN ==> Suc n : ODD"
  3528       evenI "n : ODD ==> Suc n : EVEN"
  3529 
  3530 new theorem list "elims" contains an elimination rule for each of the
  3531 recursive sets; inductive definitions now handle disjunctive premises
  3532 correctly (also ZF);
  3533 
  3534 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3535 "mutual_induct" no longer exists - the induction rule is always
  3536 contained in "induct";
  3537 
  3538 
  3539 * HOL/datatype package re-implemented and greatly improved: now
  3540 supports mutually recursive datatypes such as
  3541 
  3542   datatype
  3543     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3544             | SUM ('a aexp) ('a aexp)
  3545             | DIFF ('a aexp) ('a aexp)
  3546             | NUM 'a
  3547   and
  3548     'a bexp = LESS ('a aexp) ('a aexp)
  3549             | AND ('a bexp) ('a bexp)
  3550             | OR ('a bexp) ('a bexp)
  3551 
  3552 as well as indirectly recursive datatypes such as
  3553 
  3554   datatype
  3555     ('a, 'b) term = Var 'a
  3556                   | App 'b ((('a, 'b) term) list)
  3557 
  3558 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  3559 induction on mutually / indirectly recursive datatypes.
  3560 
  3561 Primrec equations are now stored in theory and can be accessed via
  3562 <function_name>.simps.
  3563 
  3564 INCOMPATIBILITIES:
  3565 
  3566   - Theories using datatypes must now have theory Datatype as an
  3567     ancestor.
  3568   - The specific <typename>.induct_tac no longer exists - use the
  3569     generic induct_tac instead.
  3570   - natE has been renamed to nat.exhaust - use exhaust_tac
  3571     instead of res_inst_tac ... natE. Note that the variable
  3572     names in nat.exhaust differ from the names in natE, this
  3573     may cause some "fragile" proofs to fail.
  3574   - The theorems split_<typename>_case and split_<typename>_case_asm
  3575     have been renamed to <typename>.split and <typename>.split_asm.
  3576   - Since default sorts of type variables are now handled correctly,
  3577     some datatype definitions may have to be annotated with explicit
  3578     sort constraints.
  3579   - Primrec definitions no longer require function name and type
  3580     of recursive argument.
  3581 
  3582 Consider using isatool fixdatatype to adapt your theories and proof
  3583 scripts to the new package (backup your sources first!).
  3584 
  3585 
  3586 * HOL/record package: considerably improved implementation; now
  3587 includes concrete syntax for record types, terms, updates; theorems
  3588 for surjective pairing and splitting !!-bound record variables; proof
  3589 support is as follows:
  3590 
  3591   1) standard conversions (selectors or updates applied to record
  3592 constructor terms) are part of the standard simpset;
  3593 
  3594   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  3595 made part of standard simpset and claset via addIffs;
  3596 
  3597   3) a tactic for record field splitting (record_split_tac) is part of
  3598 the standard claset (addSWrapper);
  3599 
  3600 To get a better idea about these rules you may retrieve them via
  3601 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  3602 the name of your record type.
  3603 
  3604 The split tactic 3) conceptually simplifies by the following rule:
  3605 
  3606   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  3607 
  3608 Thus any record variable that is bound by meta-all will automatically
  3609 blow up into some record constructor term, consequently the
  3610 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  3611 solve record problems automatically.
  3612 
  3613 
  3614 * reorganized the main HOL image: HOL/Integ and String loaded by
  3615 default; theory Main includes everything;
  3616 
  3617 * automatic simplification of integer sums and comparisons, using cancellation;
  3618 
  3619 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  3620 
  3621 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  3622 
  3623 * many new identities for unions, intersections, set difference, etc.;
  3624 
  3625 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  3626 called split_if, split_split, split_sum_case and split_nat_case (to go
  3627 with add/delsplits);
  3628 
  3629 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  3630 (?x::unit) = (); this is made part of the default simpset, which COULD
  3631 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  3632 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  3633 unit_abs_eta_conv is added in order to counter the effect of
  3634 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  3635 %u.f();
  3636 
  3637 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3638 makes more sense);
  3639 
  3640 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3641   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3642   disjointness reasoning but breaking a few old proofs.
  3643 
  3644 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3645 to 'converse' from 'inverse' (for compatibility with ZF and some
  3646 literature);
  3647 
  3648 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3649 the well-founded relation;
  3650 
  3651 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3652     Compl A.  The "Compl" syntax remains available as input syntax for this
  3653     release ONLY.
  3654 
  3655 * HOL/Update: new theory of function updates:
  3656     f(a:=b) == %x. if x=a then b else f x
  3657 may also be iterated as in f(a:=b,c:=d,...);
  3658 
  3659 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  3660 
  3661 * HOL/List:
  3662   - new function list_update written xs[i:=v] that updates the i-th
  3663     list position. May also be iterated as in xs[i:=a,j:=b,...].
  3664   - new function `upt' written [i..j(] which generates the list
  3665     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  3666     bound write [i..j], which is a shorthand for [i..j+1(].
  3667   - new lexicographic orderings and corresponding wellfoundedness theorems.
  3668 
  3669 * HOL/Arith:
  3670   - removed 'pred' (predecessor) function;
  3671   - generalized some theorems about n-1;
  3672   - many new laws about "div" and "mod";
  3673   - new laws about greatest common divisors (see theory ex/Primes);
  3674 
  3675 * HOL/Relation: renamed the relational operator r^-1 "converse"
  3676 instead of "inverse";
  3677 
  3678 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  3679   of the multiset ordering;
  3680 
  3681 * directory HOL/Real: a construction of the reals using Dedekind cuts
  3682   (not included by default);
  3683 
  3684 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  3685 
  3686 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  3687   programs, i.e. different program variables may have different types.
  3688 
  3689 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3690   [previously, this check worked only if the rewrite rule was unconditional]
  3691   Now rew can involve either definitions or equalities (either == or =).
  3692 
  3693 
  3694 *** ZF ***
  3695 
  3696 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  3697   only the theorems proved on ZF.ML;
  3698 
  3699 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3700   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3701   disjointness reasoning but breaking a few old proofs.
  3702 
  3703 * ZF/Update: new theory of function updates
  3704     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  3705   may also be iterated as in f(a:=b,c:=d,...);
  3706 
  3707 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  3708 
  3709 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3710   [previously, this check worked only if the rewrite rule was unconditional]
  3711   Now rew can involve either definitions or equalities (either == or =).
  3712 
  3713 * case_tac provided for compatibility with HOL
  3714     (like the old excluded_middle_tac, but with subgoals swapped)
  3715 
  3716 
  3717 *** Internal programming interfaces ***
  3718 
  3719 * Pure: several new basic modules made available for general use, see
  3720 also src/Pure/README;
  3721 
  3722 * improved the theory data mechanism to support encapsulation (data
  3723 kind name replaced by private Object.kind, acting as authorization
  3724 key); new type-safe user interface via functor TheoryDataFun; generic
  3725 print_data function becomes basically useless;
  3726 
  3727 * removed global_names compatibility flag -- all theory declarations
  3728 are qualified by default;
  3729 
  3730 * module Pure/Syntax now offers quote / antiquote translation
  3731 functions (useful for Hoare logic etc. with implicit dependencies);
  3732 see HOL/ex/Antiquote for an example use;
  3733 
  3734 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  3735 cterm -> thm;
  3736 
  3737 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  3738 subgoal;
  3739 
  3740 * Display.print_goals function moved to Locale.print_goals;
  3741 
  3742 * standard print function for goals supports current_goals_markers
  3743 variable for marking begin of proof, end of proof, start of goal; the
  3744 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  3745 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  3746 for example;
  3747 
  3748 
  3749 
  3750 New in Isabelle98 (January 1998)
  3751 --------------------------------
  3752 
  3753 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3754 
  3755 * changed lexical syntax of terms / types: dots made part of long
  3756 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  3757 
  3758 * simpset (and claset) reference variable replaced by functions
  3759 simpset / simpset_ref;
  3760 
  3761 * no longer supports theory aliases (via merge) and non-trivial
  3762 implicit merge of thms' signatures;
  3763 
  3764 * most internal names of constants changed due to qualified names;
  3765 
  3766 * changed Pure/Sequence interface (see Pure/seq.ML);
  3767 
  3768 
  3769 *** General Changes ***
  3770 
  3771 * hierachically structured name spaces (for consts, types, axms, thms
  3772 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  3773 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  3774 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  3775 long_names for fully qualified output names; NOTE: ML programs
  3776 (special tactics, packages etc.) referring to internal names may have
  3777 to be adapted to cope with fully qualified names; in case of severe
  3778 backward campatibility problems try setting 'global_names' at compile
  3779 time to have enrything declared within a flat name space; one may also
  3780 fine tune name declarations in theories via the 'global' and 'local'
  3781 section;
  3782 
  3783 * reimplemented the implicit simpset and claset using the new anytype
  3784 data filed in signatures; references simpset:simpset ref etc. are
  3785 replaced by functions simpset:unit->simpset and
  3786 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  3787 to patch your ML files accordingly;
  3788 
  3789 * HTML output now includes theory graph data for display with Java
  3790 applet or isatool browser; data generated automatically via isatool
  3791 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  3792 
  3793 * defs may now be conditional; improved rewrite_goals_tac to handle
  3794 conditional equations;
  3795 
  3796 * defs now admits additional type arguments, using TYPE('a) syntax;
  3797 
  3798 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  3799 creates a new theory node; implicit merge of thms' signatures is
  3800 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  3801 transfer:theory->thm->thm in (rare) cases;
  3802 
  3803 * improved handling of draft signatures / theories; draft thms (and
  3804 ctyps, cterms) are automatically promoted to real ones;
  3805 
  3806 * slightly changed interfaces for oracles: admit many per theory, named
  3807 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  3808 
  3809 * print_goals: optional output of const types (set show_consts and
  3810 show_types);
  3811 
  3812 * improved output of warnings (###) and errors (***);
  3813 
  3814 * subgoal_tac displays a warning if the new subgoal has type variables;
  3815 
  3816 * removed old README and Makefiles;
  3817 
  3818 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  3819 
  3820 * removed obsolete init_pps and init_database;
  3821 
  3822 * deleted the obsolete tactical STATE, which was declared by
  3823     fun STATE tacfun st = tacfun st st;
  3824 
  3825 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  3826 (which abbreviates $HOME);
  3827 
  3828 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  3829 use isatool fixseq to adapt your ML programs (this works for fully
  3830 qualified references to the Sequence structure only!);
  3831 
  3832 * use_thy no longer requires writable current directory; it always
  3833 reloads .ML *and* .thy file, if either one is out of date;
  3834 
  3835 
  3836 *** Classical Reasoner ***
  3837 
  3838 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  3839 tactics that use classical reasoning to simplify a subgoal without
  3840 splitting it into several subgoals;
  3841 
  3842 * Safe_tac: like safe_tac but uses the default claset;
  3843 
  3844 
  3845 *** Simplifier ***
  3846 
  3847 * added simplification meta rules:
  3848     (asm_)(full_)simplify: simpset -> thm -> thm;
  3849 
  3850 * simplifier.ML no longer part of Pure -- has to be loaded by object
  3851 logics (again);
  3852 
  3853 * added prems argument to simplification procedures;
  3854 
  3855 * HOL, FOL, ZF: added infix function `addsplits':
  3856   instead of `<simpset> setloop (split_tac <thms>)'
  3857   you can simply write `<simpset> addsplits <thms>'
  3858 
  3859 
  3860 *** Syntax ***
  3861 
  3862 * TYPE('a) syntax for type reflection terms;
  3863 
  3864 * no longer handles consts with name "" -- declare as 'syntax' instead;
  3865 
  3866 * pretty printer: changed order of mixfix annotation preference (again!);
  3867 
  3868 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  3869 
  3870 
  3871 *** HOL ***
  3872 
  3873 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  3874   with `addloop' of the simplifier to faciliate case splitting in premises.
  3875 
  3876 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  3877 
  3878 * HOL/Auth: new protocol proofs including some for the Internet
  3879   protocol TLS;
  3880 
  3881 * HOL/Map: new theory of `maps' a la VDM;
  3882 
  3883 * HOL/simplifier: simplification procedures nat_cancel_sums for
  3884 cancelling out common nat summands from =, <, <= (in)equalities, or
  3885 differences; simplification procedures nat_cancel_factor for
  3886 cancelling common factor from =, <, <= (in)equalities over natural
  3887 sums; nat_cancel contains both kinds of procedures, it is installed by
  3888 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  3889 
  3890 * HOL/simplifier: terms of the form
  3891   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  3892   are rewritten to
  3893   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  3894   and those of the form
  3895   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  3896   are rewritten to
  3897   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  3898 
  3899 * HOL/datatype
  3900   Each datatype `t' now comes with a theorem `split_t_case' of the form
  3901 
  3902   P(t_case f1 ... fn x) =
  3903      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  3904         ...
  3905        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  3906      )
  3907 
  3908   and a theorem `split_t_case_asm' of the form
  3909 
  3910   P(t_case f1 ... fn x) =
  3911     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  3912         ...
  3913        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  3914      )
  3915   which can be added to a simpset via `addsplits'. The existing theorems
  3916   expand_list_case and expand_option_case have been renamed to
  3917   split_list_case and split_option_case.
  3918 
  3919 * HOL/Arithmetic:
  3920   - `pred n' is automatically converted to `n-1'.
  3921     Users are strongly encouraged not to use `pred' any longer,
  3922     because it will disappear altogether at some point.
  3923   - Users are strongly encouraged to write "0 < n" rather than
  3924     "n ~= 0". Theorems and proof tools have been modified towards this
  3925     `standard'.
  3926 
  3927 * HOL/Lists:
  3928   the function "set_of_list" has been renamed "set" (and its theorems too);
  3929   the function "nth" now takes its arguments in the reverse order and
  3930   has acquired the infix notation "!" as in "xs!n".
  3931 
  3932 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  3933 
  3934 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  3935   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  3936 
  3937 * HOL/record: extensible records with schematic structural subtyping
  3938 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  3939 still lacks various theorems and concrete record syntax;
  3940 
  3941 
  3942 *** HOLCF ***
  3943 
  3944 * removed "axioms" and "generated by" sections;
  3945 
  3946 * replaced "ops" section by extended "consts" section, which is capable of
  3947   handling the continuous function space "->" directly;
  3948 
  3949 * domain package:
  3950   . proves theorems immediately and stores them in the theory,
  3951   . creates hierachical name space,
  3952   . now uses normal mixfix annotations (instead of cinfix...),
  3953   . minor changes to some names and values (for consistency),
  3954   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  3955   . separator between mutual domain defs: changed "," to "and",
  3956   . improved handling of sort constraints;  now they have to
  3957     appear on the left-hand side of the equations only;
  3958 
  3959 * fixed LAM <x,y,zs>.b syntax;
  3960 
  3961 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  3962 adm (%x. P (t x)), where P is chainfinite and t continuous;
  3963 
  3964 
  3965 *** FOL and ZF ***
  3966 
  3967 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  3968   with `addloop' of the simplifier to faciliate case splitting in premises.
  3969 
  3970 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  3971 in HOL, they strip ALL and --> from proved theorems;
  3972 
  3973 
  3974 
  3975 New in Isabelle94-8 (May 1997)
  3976 ------------------------------
  3977 
  3978 *** General Changes ***
  3979 
  3980 * new utilities to build / run / maintain Isabelle etc. (in parts
  3981 still somewhat experimental); old Makefiles etc. still functional;
  3982 
  3983 * new 'Isabelle System Manual';
  3984 
  3985 * INSTALL text, together with ./configure and ./build scripts;
  3986 
  3987 * reimplemented type inference for greater efficiency, better error
  3988 messages and clean internal interface;
  3989 
  3990 * prlim command for dealing with lots of subgoals (an easier way of
  3991 setting goals_limit);
  3992 
  3993 
  3994 *** Syntax ***
  3995 
  3996 * supports alternative (named) syntax tables (parser and pretty
  3997 printer); internal interface is provided by add_modesyntax(_i);
  3998 
  3999 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4000 be used in conjunction with the Isabelle symbol font; uses the
  4001 "symbols" syntax table;
  4002 
  4003 * added token_translation interface (may translate name tokens in
  4004 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4005 the current print_mode); IMPORTANT: user print translation functions
  4006 are responsible for marking newly introduced bounds
  4007 (Syntax.mark_boundT);
  4008 
  4009 * token translations for modes "xterm" and "xterm_color" that display
  4010 names in bold, underline etc. or colors (which requires a color
  4011 version of xterm);
  4012 
  4013 * infixes may now be declared with names independent of their syntax;
  4014 
  4015 * added typed_print_translation (like print_translation, but may
  4016 access type of constant);
  4017 
  4018 
  4019 *** Classical Reasoner ***
  4020 
  4021 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4022 some limitations.  Blast_tac...
  4023   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4024   + ignores elimination rules that don't have the correct format
  4025         (the conclusion MUST be a formula variable)
  4026   + ignores types, which can make HOL proofs fail
  4027   + rules must not require higher-order unification, e.g. apply_type in ZF
  4028     [message "Function Var's argument not a bound variable" relates to this]
  4029   + its proof strategy is more general but can actually be slower
  4030 
  4031 * substitution with equality assumptions no longer permutes other
  4032 assumptions;
  4033 
  4034 * minor changes in semantics of addafter (now called addaltern); renamed
  4035 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4036 (and access functions for it);
  4037 
  4038 * improved combination of classical reasoner and simplifier:
  4039   + functions for handling clasimpsets
  4040   + improvement of addss: now the simplifier is called _after_ the
  4041     safe steps.
  4042   + safe variant of addss called addSss: uses safe simplifications
  4043     _during_ the safe steps. It is more complete as it allows multiple
  4044     instantiations of unknowns (e.g. with slow_tac).
  4045 
  4046 *** Simplifier ***
  4047 
  4048 * added interface for simplification procedures (functions that
  4049 produce *proven* rewrite rules on the fly, depending on current
  4050 redex);
  4051 
  4052 * ordering on terms as parameter (used for ordered rewriting);
  4053 
  4054 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4055 
  4056 * the solver is now split into a safe and an unsafe part.
  4057 This should be invisible for the normal user, except that the
  4058 functions setsolver and addsolver have been renamed to setSolver and
  4059 addSolver; added safe_asm_full_simp_tac;
  4060 
  4061 
  4062 *** HOL ***
  4063 
  4064 * a generic induction tactic `induct_tac' which works for all datatypes and
  4065 also for type `nat';
  4066 
  4067 * a generic case distinction tactic `exhaust_tac' which works for all
  4068 datatypes and also for type `nat';
  4069 
  4070 * each datatype comes with a function `size';
  4071 
  4072 * patterns in case expressions allow tuple patterns as arguments to
  4073 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4074 
  4075 * primrec now also works with type nat;
  4076 
  4077 * recdef: a new declaration form, allows general recursive functions to be
  4078 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4079 
  4080 * the constant for negation has been renamed from "not" to "Not" to
  4081 harmonize with FOL, ZF, LK, etc.;
  4082 
  4083 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4084 infinite lists;
  4085 
  4086 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4087 
  4088 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4089 problems in commutative rings, using axiomatic type classes for + and *;
  4090 
  4091 * more examples in HOL/MiniML and HOL/Auth;
  4092 
  4093 * more default rewrite rules for quantifiers, union/intersection;
  4094 
  4095 * a new constant `arbitrary == @x.False';
  4096 
  4097 * HOLCF/IOA replaces old HOL/IOA;
  4098 
  4099 * HOLCF changes: derived all rules and arities
  4100   + axiomatic type classes instead of classes
  4101   + typedef instead of faking type definitions
  4102   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4103   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4104   + eliminated the types void, one, tr
  4105   + use unit lift and bool lift (with translations) instead of one and tr
  4106   + eliminated blift from Lift3.thy (use Def instead of blift)
  4107   all eliminated rules are derived as theorems --> no visible changes ;
  4108 
  4109 
  4110 *** ZF ***
  4111 
  4112 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4113 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4114 as ZF_cs addSIs [equalityI];
  4115 
  4116 
  4117 
  4118 New in Isabelle94-7 (November 96)
  4119 ---------------------------------
  4120 
  4121 * allowing negative levels (as offsets) in prlev and choplev;
  4122 
  4123 * super-linear speedup for large simplifications;
  4124 
  4125 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4126 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4127 FAIL); can suppress it using the command Delsimps (ex_simps @
  4128 all_simps); De Morgan laws are also now included, by default;
  4129 
  4130 * improved printing of ==>  :  ~:
  4131 
  4132 * new object-logic "Sequents" adds linear logic, while replacing LK
  4133 and Modal (thanks to Sara Kalvala);
  4134 
  4135 * HOL/Auth: correctness proofs for authentication protocols;
  4136 
  4137 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4138 examples on HOL/Auth);
  4139 
  4140 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4141 the rewriter and classical reasoner simultaneously;
  4142 
  4143 * function uresult no longer returns theorems in "standard" format;
  4144 regain previous version by: val uresult = standard o uresult;
  4145 
  4146 
  4147 
  4148 New in Isabelle94-6
  4149 -------------------
  4150 
  4151 * oracles -- these establish an interface between Isabelle and trusted
  4152 external reasoners, which may deliver results as theorems;
  4153 
  4154 * proof objects (in particular record all uses of oracles);
  4155 
  4156 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4157 
  4158 * "constdefs" section in theory files;
  4159 
  4160 * "primrec" section (HOL) no longer requires names;
  4161 
  4162 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4163 
  4164 
  4165 
  4166 New in Isabelle94-5
  4167 -------------------
  4168 
  4169 * reduced space requirements;
  4170 
  4171 * automatic HTML generation from theories;
  4172 
  4173 * theory files no longer require "..." (quotes) around most types;
  4174 
  4175 * new examples, including two proofs of the Church-Rosser theorem;
  4176 
  4177 * non-curried (1994) version of HOL is no longer distributed;
  4178 
  4179 
  4180 
  4181 New in Isabelle94-4
  4182 -------------------
  4183 
  4184 * greatly reduced space requirements;
  4185 
  4186 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4187 
  4188 * searchable theorem database (see the section "Retrieving theorems" on
  4189 page 8 of the Reference Manual);
  4190 
  4191 * new examples, including Grabczewski's monumental case study of the
  4192 Axiom of Choice;
  4193 
  4194 * The previous version of HOL renamed to Old_HOL;
  4195 
  4196 * The new version of HOL (previously called CHOL) uses a curried syntax
  4197 for functions.  Application looks like f a b instead of f(a,b);
  4198 
  4199 * Mutually recursive inductive definitions finally work in HOL;
  4200 
  4201 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4202 translates to the operator "split";
  4203 
  4204 
  4205 
  4206 New in Isabelle94-3
  4207 -------------------
  4208 
  4209 * new infix operator, addss, allowing the classical reasoner to
  4210 perform simplification at each step of its search.  Example:
  4211         fast_tac (cs addss ss)
  4212 
  4213 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4214 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4215 look like (a,b) instead of <a,b>;
  4216 
  4217 * PLEASE NOTE: CHOL will eventually replace HOL!
  4218 
  4219 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4220 It translates to the operator "split".  A new theory of integers is available;
  4221 
  4222 * In ZF, integer numerals now denote two's-complement binary integers.
  4223 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4224 
  4225 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4226 of the Axiom of Choice;
  4227 
  4228 
  4229 
  4230 New in Isabelle94-2
  4231 -------------------
  4232 
  4233 * Significantly faster resolution;
  4234 
  4235 * the different sections in a .thy file can now be mixed and repeated
  4236 freely;
  4237 
  4238 * Database of theorems for FOL, HOL and ZF.  New
  4239 commands including qed, qed_goal and bind_thm store theorems in the database.
  4240 
  4241 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4242 a given theory (thms_of), or find out what theory a theorem was proved in
  4243 (theory_of_thm);
  4244 
  4245 * Bugs fixed in the inductive definition and datatype packages;
  4246 
  4247 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4248 and HOL_dup_cs obsolete;
  4249 
  4250 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4251 have been removed;
  4252 
  4253 * Simpler definition of function space in ZF;
  4254 
  4255 * new results about cardinal and ordinal arithmetic in ZF;
  4256 
  4257 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4258 types;
  4259 
  4260 
  4261 $Id$