NEWS
author haftmann
Fri Jun 01 10:44:24 2007 +0200 (2007-06-01)
changeset 23180 80b9caed2ba8
parent 23129 a318773dca05
child 23210 a0cb15114e7a
permissions -rw-r--r--
fixed typo
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * More uniform information about legacy features, notably a
    10 warning/error of "Legacy feature: ...", depending on the state of the
    11 tolerate_legacy_features flag (default true).
    12 
    13 * Theory syntax: the header format ``theory A = B + C:'' has been
    14 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    15 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    16 
    17 * Theory syntax: the old non-Isar theory file format has been
    18 discontinued altogether.  Note that ML proof scripts may still be used
    19 with Isar theories; migration is usually quite simple with the ML
    20 function use_legacy_bindings.  INCOMPATIBILITY.
    21 
    22 * Theory syntax: some popular names (e.g. 'class', 'declaration',
    23 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
    24 quotes.
    25 
    26 * Legacy goal package: reduced interface to the bare minimum required
    27 to keep existing proof scripts running.  Most other user-level
    28 functions are now part of the OldGoals structure, which is *not* open
    29 by default (consider isatool expandshort before open OldGoals).
    30 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    31 these tend to cause confusion about the actual goal (!) context being
    32 used here, which is not necessarily the same as the_context().
    33 
    34 * Command 'find_theorems': support "*" wildcard in "name:" criterion.
    35 
    36 * Proof General interface: A search form for the "Find Theorems" command is
    37 now available via C-c C-a C-f.  The old minibuffer interface is available
    38 via C-c C-a C-m.  Variable proof-find-theorems-command (customizable via
    39 'Proof-General -> Advanced -> Internals -> Prover Config') controls the
    40 default behavior of 'ProofGeneral -> Find Theorems' (C-c C-f): set to
    41 isar-find-theorems-form or isar-find-theorems-minibuffer.
    42 
    43 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    44 by default, which means that "prems" (and also "fixed variables") are
    45 suppressed from proof state output.  Note that the ProofGeneral
    46 settings mechanism allows to change and save options persistently, but
    47 older versions of Isabelle will fail to start up if a negative prems
    48 limit is imposed.
    49 
    50 * Local theory targets may be specified by non-nested blocks of
    51 ``context/locale/class ... begin'' followed by ``end''.  The body may
    52 contain definitions, theorems etc., including any derived mechanism
    53 that has been implemented on top of these primitives.  This concept
    54 generalizes the existing ``theorem (in ...)'' towards more versatility
    55 and scalability.
    56 
    57 * Proof General interface: proper undo of final 'end' command;
    58 discontinued Isabelle/classic mode (ML proof scripts).
    59 
    60 
    61 *** Document preparation ***
    62 
    63 * Added antiquotation @{theory name} which prints the given name,
    64 after checking that it refers to a valid ancestor theory in the
    65 current context.
    66 
    67 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    68 check the given source text as ML type/structure, printing verbatim.
    69 
    70 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    71 "c args == rhs" given in the current context.  (Any number of
    72 arguments may be given on the LHS.)
    73 
    74 
    75 
    76 *** Pure ***
    77 
    78 * code generator: consts in 'consts_code' Isar commands are now referred
    79   to by usual term syntax (including optional type annotations).
    80 
    81 * code generator: 
    82   - Isar 'definition's, 'constdef's and primitive instance definitions are added
    83     explicitly to the table of defining equations
    84   - primitive definitions are not used as defining equations by default any longer
    85   - defining equations are now definitly restricted to meta "==" and object
    86         equality "="
    87   - HOL theories have been adopted accordingly
    88 
    89 * class_package.ML offers a combination of axclasses and locales to
    90 achieve Haskell-like type classes in Isabelle.  See
    91 HOL/ex/Classpackage.thy for examples.
    92 
    93 * Yet another code generator framework allows to generate executable
    94 code for ML and Haskell (including "class"es).  A short usage sketch:
    95 
    96     internal compilation:
    97         code_gen <list of constants (term syntax)> (SML #)
    98     writing SML code to a file:
    99         code_gen <list of constants (term syntax)> (SML <filename>)
   100     writing OCaml code to a file:
   101         code_gen <list of constants (term syntax)> (OCaml <filename>)
   102     writing Haskell code to a bunch of files:
   103         code_gen <list of constants (term syntax)> (Haskell <filename>)
   104 
   105 Reasonable default setup of framework in HOL/Main.
   106 
   107 Theorem attributs for selecting and transforming function equations theorems:
   108 
   109     [code fun]:        select a theorem as function equation for a specific constant
   110     [code fun del]:    deselect a theorem as function equation for a specific constant
   111     [code inline]:     select an equation theorem for unfolding (inlining) in place
   112     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   113 
   114 User-defined serializations (target in {SML, OCaml, Haskell}):
   115 
   116     code_const <and-list of constants (term syntax)>
   117       {(target) <and-list of const target syntax>}+
   118 
   119     code_type <and-list of type constructors>
   120       {(target) <and-list of type target syntax>}+
   121 
   122     code_instance <and-list of instances>
   123       {(target)}+
   124         where instance ::= <type constructor> :: <class>
   125 
   126     code_class <and_list of classes>
   127       {(target) <and-list of class target syntax>}+
   128         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   129 
   130 code_instance and code_class only apply to target Haskell.
   131 
   132 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   133 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   134 
   135 * Command 'no_translations' removes translation rules from theory
   136 syntax.
   137 
   138 * Overloaded definitions are now actually checked for acyclic
   139 dependencies.  The overloading scheme is slightly more general than
   140 that of Haskell98, although Isabelle does not demand an exact
   141 correspondence to type class and instance declarations.
   142 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   143 exotic versions of overloading -- at the discretion of the user!
   144 
   145 Polymorphic constants are represented via type arguments, i.e. the
   146 instantiation that matches an instance against the most general
   147 declaration given in the signature.  For example, with the declaration
   148 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   149 as c(nat).  Overloading is essentially simultaneous structural
   150 recursion over such type arguments.  Incomplete specification patterns
   151 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   152 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   153 Command 'print_theory' outputs the normalized system of recursive
   154 equations, see section "definitions".
   155 
   156 * Isar: improper proof element 'guess' is like 'obtain', but derives
   157 the obtained context from the course of reasoning!  For example:
   158 
   159   assume "EX x y. A x & B y"   -- "any previous fact"
   160   then guess x and y by clarify
   161 
   162 This technique is potentially adventurous, depending on the facts and
   163 proof tools being involved here.
   164 
   165 * Isar: known facts from the proof context may be specified as literal
   166 propositions, using ASCII back-quote syntax.  This works wherever
   167 named facts used to be allowed so far, in proof commands, proof
   168 methods, attributes etc.  Literal facts are retrieved from the context
   169 according to unification of type and term parameters.  For example,
   170 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   171 theorems in the current context, then these are valid literal facts:
   172 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   173 
   174 There is also a proof method "fact" which does the same composition
   175 for explicit goal states, e.g. the following proof texts coincide with
   176 certain special cases of literal facts:
   177 
   178   have "A" by fact                 ==  note `A`
   179   have "A ==> B" by fact           ==  note `A ==> B`
   180   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   181   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   182 
   183 * Isar: ":" (colon) is no longer a symbolic identifier character in
   184 outer syntax.  Thus symbolic identifiers may be used without
   185 additional white space in declarations like this: ``assume *: A''.
   186 
   187 * Isar: 'print_facts' prints all local facts of the current context,
   188 both named and unnamed ones.
   189 
   190 * Isar: 'def' now admits simultaneous definitions, e.g.:
   191 
   192   def x == "t" and y == "u"
   193 
   194 * Isar: added command 'unfolding', which is structurally similar to
   195 'using', but affects both the goal state and facts by unfolding given
   196 rewrite rules.  Thus many occurrences of the 'unfold' method or
   197 'unfolded' attribute may be replaced by first-class proof text.
   198 
   199 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   200 and command 'unfolding' now all support object-level equalities
   201 (potentially conditional).  The underlying notion of rewrite rule is
   202 analogous to the 'rule_format' attribute, but *not* that of the
   203 Simplifier (which is usually more generous).
   204 
   205 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   206 method expression within a sandbox consisting of the first N
   207 sub-goals, which need to exist.  For example, ``simp_all [3]''
   208 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   209 simplifies all new goals that emerge from applying rule foo to the
   210 originally first one.
   211 
   212 * Isar: schematic goals are no longer restricted to higher-order
   213 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   214 expected.
   215 
   216 * Isar: the conclusion of a long theorem statement is now either
   217 'shows' (a simultaneous conjunction, as before), or 'obtains'
   218 (essentially a disjunction of cases with local parameters and
   219 assumptions).  The latter allows to express general elimination rules
   220 adequately; in this notation common elimination rules look like this:
   221 
   222   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   223     assumes "EX x. P x"
   224     obtains x where "P x"
   225 
   226   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   227     assumes "A & B"
   228     obtains A and B
   229 
   230   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   231     assumes "A | B"
   232     obtains
   233       A
   234     | B
   235 
   236 The subsequent classical rules even refer to the formal "thesis"
   237 explicitly:
   238 
   239   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   240     obtains "~ thesis"
   241 
   242   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   243     obtains "thesis ==> something"
   244 
   245 The actual proof of an 'obtains' statement is analogous to that of the
   246 Isar proof element 'obtain', only that there may be several cases.
   247 Optional case names may be specified in parentheses; these will be
   248 available both in the present proof and as annotations in the
   249 resulting rule, for later use with the 'cases' method (cf. attribute
   250 case_names).
   251 
   252 * Isar: the assumptions of a long theorem statement are available as
   253 "assms" fact in the proof context.  This is more appropriate than the
   254 (historical) "prems", which refers to all assumptions of the current
   255 context, including those from the target locale, proof body etc.
   256 
   257 * Isar: 'print_statement' prints theorems from the current theory or
   258 proof context in long statement form, according to the syntax of a
   259 top-level lemma.
   260 
   261 * Isar: 'obtain' takes an optional case name for the local context
   262 introduction rule (default "that").
   263 
   264 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   265 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   266 to occur.
   267 
   268 * Pure: syntax "CONST name" produces a fully internalized constant
   269 according to the current context.  This is particularly useful for
   270 syntax translations that should refer to internal constant
   271 representations independently of name spaces.
   272 
   273 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   274 instead of "FOO ". This allows multiple binder declarations to coexist
   275 in the same context.  INCOMPATIBILITY.
   276 
   277 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   278 primitive that also works in a locale context (both for constants and
   279 fixed variables).  Type declaration and internal syntactic
   280 representation of given constants retrieved from the context.
   281 
   282 * Isar/locales: new derived specification elements 'axiomatization',
   283 'definition', 'abbreviation', which support type-inference, admit
   284 object-level specifications (equality, equivalence).  See also the
   285 isar-ref manual.  Examples:
   286 
   287   axiomatization
   288     eq  (infix "===" 50) where
   289     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   290 
   291   definition "f x y = x + y + 1"
   292   definition g where "g x = f x x"
   293 
   294   abbreviation
   295     neq  (infix "=!=" 50) where
   296     "x =!= y == ~ (x === y)"
   297 
   298 These specifications may be also used in a locale context.  Then the
   299 constants being introduced depend on certain fixed parameters, and the
   300 constant name is qualified by the locale base name.  An internal
   301 abbreviation takes care for convenient input and output, making the
   302 parameters implicit and using the original short name.  See also
   303 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   304 entities from a monomorphic theory.
   305 
   306 Presently, abbreviations are only available 'in' a target locale, but
   307 not inherited by general import expressions.  Also note that
   308 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   309 'translations' in common applications.
   310 
   311 Concrete syntax is attached to specified constants in internal form,
   312 independently of name spaces.  The parse tree representation is
   313 slightly different -- use 'notation' instead of raw 'syntax', and
   314 'translations' with explicit "CONST" markup to accommodate this.
   315 
   316 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   317 the current context.  Print mode "no_abbrevs" prevents inversion of
   318 abbreviations on output.
   319 
   320 * Isar/locales: improved parameter handling:
   321 - use of locales "var" and "struct" no longer necessary;
   322 - parameter renamings are no longer required to be injective.
   323   This enables, for example, to define a locale for endomorphisms thus:
   324   locale endom = homom mult mult h.
   325 
   326 * Isar/locales: changed the way locales with predicates are defined.
   327 Instead of accumulating the specification, the imported expression is
   328 now an interpretation.  INCOMPATIBILITY: different normal form of
   329 locale expressions.  In particular, in interpretations of locales with
   330 predicates, goals repesenting already interpreted fragments are not
   331 removed automatically.  Use methods `intro_locales' and
   332 `unfold_locales'; see below.
   333 
   334 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   335 provide backward reasoning on locales predicates.  The methods are
   336 aware of interpretations and discharge corresponding goals.
   337 `intro_locales' is less aggressive then `unfold_locales' and does not
   338 unfold predicates to assumptions.
   339 
   340 * Isar/locales: the order in which locale fragments are accumulated
   341 has changed.  This enables to override declarations from fragments due
   342 to interpretations -- for example, unwanted simp rules.
   343 
   344 * Provers/induct: improved internal context management to support
   345 local fixes and defines on-the-fly.  Thus explicit meta-level
   346 connectives !! and ==> are rarely required anymore in inductive goals
   347 (using object-logic connectives for this purpose has been long
   348 obsolete anyway).  The subsequent proof patterns illustrate advanced
   349 techniques of natural induction; general datatypes and inductive sets
   350 work analogously (see also src/HOL/Lambda for realistic examples).
   351 
   352 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   353 parameters:
   354 
   355   lemma
   356     fixes n :: nat and x :: 'a
   357     assumes a: "A n x"
   358     shows "P n x"
   359     using a                     -- {* make induct insert fact a *}
   360   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   361     case 0
   362     show ?case sorry
   363   next
   364     case (Suc n)
   365     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   366     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   367     show ?case sorry
   368   qed
   369 
   370 (2) This is how to perform induction over ``expressions of a certain
   371 form'', using a locally defined inductive parameter n == "a x"
   372 together with strengthening (the latter is usually required to get
   373 sufficiently flexible induction hypotheses):
   374 
   375   lemma
   376     fixes a :: "'a => nat"
   377     assumes a: "A (a x)"
   378     shows "P (a x)"
   379     using a
   380   proof (induct n == "a x" arbitrary: x)
   381     ...
   382 
   383 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   384 particular technique.
   385 
   386 (3) This is how to perform existential reasoning ('obtains' or
   387 'obtain') by induction, while avoiding explicit object-logic
   388 encodings:
   389 
   390   lemma
   391     fixes n :: nat
   392     obtains x :: 'a where "P n x" and "Q n x"
   393   proof (induct n arbitrary: thesis)
   394     case 0
   395     obtain x where "P 0 x" and "Q 0 x" sorry
   396     then show thesis by (rule 0)
   397   next
   398     case (Suc n)
   399     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   400     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   401     then show thesis by (rule Suc.prems)
   402   qed
   403 
   404 Here the 'arbitrary: thesis' specification essentially modifies the
   405 scope of the formal thesis parameter, in order to the get the whole
   406 existence statement through the induction as expected.
   407 
   408 * Provers/induct: mutual induction rules are now specified as a list
   409 of rule sharing the same induction cases.  HOL packages usually
   410 provide foo_bar.inducts for mutually defined items foo and bar
   411 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   412 specify mutual induction rules differently, i.e. like this:
   413 
   414   (induct rule: foo_bar.inducts)
   415   (induct set: foo bar)
   416   (induct type: foo bar)
   417 
   418 The ML function ProjectRule.projections turns old-style rules into the
   419 new format.
   420 
   421 * Provers/induct: improved handling of simultaneous goals.  Instead of
   422 introducing object-level conjunction, the statement is now split into
   423 several conclusions, while the corresponding symbolic cases are
   424 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   425 explicitly.  For example:
   426 
   427   lemma
   428     fixes n :: nat
   429     shows "P n" and "Q n"
   430   proof (induct n)
   431     case 0 case 1
   432     show "P 0" sorry
   433   next
   434     case 0 case 2
   435     show "Q 0" sorry
   436   next
   437     case (Suc n) case 1
   438     note `P n` and `Q n`
   439     show "P (Suc n)" sorry
   440   next
   441     case (Suc n) case 2
   442     note `P n` and `Q n`
   443     show "Q (Suc n)" sorry
   444   qed
   445 
   446 The split into subcases may be deferred as follows -- this is
   447 particularly relevant for goal statements with local premises.
   448 
   449   lemma
   450     fixes n :: nat
   451     shows "A n ==> P n" and "B n ==> Q n"
   452   proof (induct n)
   453     case 0
   454     {
   455       case 1
   456       note `A 0`
   457       show "P 0" sorry
   458     next
   459       case 2
   460       note `B 0`
   461       show "Q 0" sorry
   462     }
   463   next
   464     case (Suc n)
   465     note `A n ==> P n` and `B n ==> Q n`
   466     {
   467       case 1
   468       note `A (Suc n)`
   469       show "P (Suc n)" sorry
   470     next
   471       case 2
   472       note `B (Suc n)`
   473       show "Q (Suc n)" sorry
   474     }
   475   qed
   476 
   477 If simultaneous goals are to be used with mutual rules, the statement
   478 needs to be structured carefully as a two-level conjunction, using
   479 lists of propositions separated by 'and':
   480 
   481   lemma
   482     shows "a : A ==> P1 a"
   483           "a : A ==> P2 a"
   484       and "b : B ==> Q1 b"
   485           "b : B ==> Q2 b"
   486           "b : B ==> Q3 b"
   487   proof (induct set: A B)
   488 
   489 * Provers/induct: support coinduction as well.  See
   490 src/HOL/Library/Coinductive_List.thy for various examples.
   491 
   492 * Attribute "symmetric" produces result with standardized schematic
   493 variables (index 0).  Potential INCOMPATIBILITY.
   494 
   495 * Simplifier: by default the simplifier trace only shows top level
   496 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   497 default. Thus there is less danger of being flooded by the trace. The
   498 trace indicates where parts have been suppressed.
   499   
   500 * Provers/classical: removed obsolete classical version of elim_format
   501 attribute; classical elim/dest rules are now treated uniformly when
   502 manipulating the claset.
   503 
   504 * Provers/classical: stricter checks to ensure that supplied intro,
   505 dest and elim rules are well-formed; dest and elim rules must have at
   506 least one premise.
   507 
   508 * Provers/classical: attributes dest/elim/intro take an optional
   509 weight argument for the rule (just as the Pure versions).  Weights are
   510 ignored by automated tools, but determine the search order of single
   511 rule steps.
   512 
   513 * Syntax: input syntax now supports dummy variable binding "%_. b",
   514 where the body does not mention the bound variable.  Note that dummy
   515 patterns implicitly depend on their context of bounds, which makes
   516 "{_. _}" match any set comprehension as expected.  Potential
   517 INCOMPATIBILITY -- parse translations need to cope with syntactic
   518 constant "_idtdummy" in the binding position.
   519 
   520 * Syntax: removed obsolete syntactic constant "_K" and its associated
   521 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   522 for example "A -> B" => "Pi A (%_. B)".
   523 
   524 * Pure: 'class_deps' command visualizes the subclass relation, using
   525 the graph browser tool.
   526 
   527 * Pure: 'print_theory' now suppresses entities with internal name
   528 (trailing "_") by default; use '!' option for full details.
   529 
   530 
   531 *** HOL ***
   532 
   533 * constant "List.op @" now named "List.append".  Use ML antiquotations
   534 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   535 possible incompatibilities when working on ML level.
   536 
   537 * Constant renames due to introduction of canonical name prefixing for
   538   class package:
   539 
   540     HOL.abs ~> HOL.minus_class.abs
   541     HOL.divide ~> HOL.divide_class.divide
   542     Nat.power ~> Nat.power_class.power
   543     Nat.size ~> Nat.size_class.size
   544     Numeral.number_of ~> Numeral.number_class.number_of
   545     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   546 
   547 * Rudimentary class target mechanism involves constant renames:
   548 
   549     Orderings.min ~> Orderings.ord_class.min
   550     Orderings.max ~> Orderings.ord_class.max
   551     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   552 
   553 * case expressions and primrec: missing cases now mapped to "undefined"
   554 instead of "arbitrary"
   555 
   556 * new constant "undefined" with axiom "undefined x = undefined"
   557 
   558 * new class "default" with associated constant "default"
   559 
   560 * new function listsum :: 'a list => 'a for arbitrary monoids.
   561   Special syntax: "SUM x <- xs. f x" (and latex variants)
   562 
   563 * Library/List_Comprehension.thy provides Haskell-like input syntax for list
   564   comprehensions.
   565 
   566 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   567     when generating code.
   568 
   569 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   570     when generating code.
   571 
   572 * Library/Commutative_Ring.thy: switched from recdef to function package;
   573     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   574 
   575 * Some steps towards more uniform lattice theory development in HOL.
   576 
   577     constants "meet" and "join" now named "inf" and "sup"
   578     constant "Meet" now named "Inf"
   579 
   580     classes "meet_semilorder" and "join_semilorder" now named
   581       "lower_semilattice" and "upper_semilattice"
   582     class "lorder" now named "lattice"
   583     class "comp_lat" now named "complete_lattice"
   584 
   585     Instantiation of lattice classes allows explicit definitions
   586     for "inf" and "sup" operations.
   587 
   588   INCOMPATIBILITY.  Theorem renames:
   589 
   590     meet_left_le            ~> inf_le1
   591     meet_right_le           ~> inf_le2
   592     join_left_le            ~> sup_ge1
   593     join_right_le           ~> sup_ge2
   594     meet_join_le            ~> inf_sup_ord
   595     le_meetI                ~> le_infI
   596     join_leI                ~> le_supI
   597     le_meet                 ~> le_inf_iff
   598     le_join                 ~> ge_sup_conv
   599     meet_idempotent         ~> inf_idem
   600     join_idempotent         ~> sup_idem
   601     meet_comm               ~> inf_commute
   602     join_comm               ~> sup_commute
   603     meet_leI1               ~> le_infI1
   604     meet_leI2               ~> le_infI2
   605     le_joinI1               ~> le_supI1
   606     le_joinI2               ~> le_supI2
   607     meet_assoc              ~> inf_assoc
   608     join_assoc              ~> sup_assoc
   609     meet_left_comm          ~> inf_left_commute
   610     meet_left_idempotent    ~> inf_left_idem
   611     join_left_comm          ~> sup_left_commute
   612     join_left_idempotent    ~> sup_left_idem
   613     meet_aci                ~> inf_aci
   614     join_aci                ~> sup_aci
   615     le_def_meet             ~> le_iff_inf
   616     le_def_join             ~> le_iff_sup
   617     join_absorp2            ~> sup_absorb2
   618     join_absorp1            ~> sup_absorb1
   619     meet_absorp1            ~> inf_absorb1
   620     meet_absorp2            ~> inf_absorb2
   621     meet_join_absorp        ~> inf_sup_absorb
   622     join_meet_absorp        ~> sup_inf_absorb
   623     distrib_join_le         ~> distrib_sup_le
   624     distrib_meet_le         ~> distrib_inf_le
   625 
   626     add_meet_distrib_left   ~> add_inf_distrib_left
   627     add_join_distrib_left   ~> add_sup_distrib_left
   628     is_join_neg_meet        ~> is_join_neg_inf
   629     is_meet_neg_join        ~> is_meet_neg_sup
   630     add_meet_distrib_right  ~> add_inf_distrib_right
   631     add_join_distrib_right  ~> add_sup_distrib_right
   632     add_meet_join_distribs  ~> add_sup_inf_distribs
   633     join_eq_neg_meet        ~> sup_eq_neg_inf
   634     meet_eq_neg_join        ~> inf_eq_neg_sup
   635     add_eq_meet_join        ~> add_eq_inf_sup
   636     meet_0_imp_0            ~> inf_0_imp_0
   637     join_0_imp_0            ~> sup_0_imp_0
   638     meet_0_eq_0             ~> inf_0_eq_0
   639     join_0_eq_0             ~> sup_0_eq_0
   640     neg_meet_eq_join        ~> neg_inf_eq_sup
   641     neg_join_eq_meet        ~> neg_sup_eq_inf
   642     join_eq_if              ~> sup_eq_if
   643 
   644     mono_meet               ~> mono_inf
   645     mono_join               ~> mono_sup
   646     meet_bool_eq            ~> inf_bool_eq
   647     join_bool_eq            ~> sup_bool_eq
   648     meet_fun_eq             ~> inf_fun_eq
   649     join_fun_eq             ~> sup_fun_eq
   650     meet_set_eq             ~> inf_set_eq
   651     join_set_eq             ~> sup_set_eq
   652     meet1_iff               ~> inf1_iff
   653     meet2_iff               ~> inf2_iff
   654     meet1I                  ~> inf1I
   655     meet2I                  ~> inf2I
   656     meet1D1                 ~> inf1D1
   657     meet2D1                 ~> inf2D1
   658     meet1D2                 ~> inf1D2
   659     meet2D2                 ~> inf2D2
   660     meet1E                  ~> inf1E
   661     meet2E                  ~> inf2E
   662     join1_iff               ~> sup1_iff
   663     join2_iff               ~> sup2_iff
   664     join1I1                 ~> sup1I1
   665     join2I1                 ~> sup2I1
   666     join1I1                 ~> sup1I1
   667     join2I2                 ~> sup1I2
   668     join1CI                 ~> sup1CI
   669     join2CI                 ~> sup2CI
   670     join1E                  ~> sup1E
   671     join2E                  ~> sup2E
   672 
   673     is_meet_Meet            ~> is_meet_Inf
   674     Meet_bool_def           ~> Inf_bool_def
   675     Meet_fun_def            ~> Inf_fun_def
   676     Meet_greatest           ~> Inf_greatest
   677     Meet_lower              ~> Inf_lower
   678     Meet_set_def            ~> Inf_set_def
   679 
   680     listsp_meetI            ~> listsp_infI
   681     listsp_meet_eq          ~> listsp_inf_eq
   682 
   683     meet_min                ~> inf_min
   684     join_max                ~> sup_max
   685 
   686 * Classes "order" and "linorder": facts "refl", "trans" and
   687 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   688 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   689 
   690 * Classes "order" and "linorder": 
   691 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   692 proofs changed.
   693 
   694 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   695 INCOMPATIBILITY.
   696 
   697 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   698 INCOMPATIBILITY.
   699 
   700 * Added syntactic class "size"; overloaded constant "size" now has
   701 type "'a::size ==> bool"
   702 
   703 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   704 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   705 
   706 * Added method "lexicographic_order" automatically synthesizes
   707 termination relations as lexicographic combinations of size measures
   708 -- 'function' package.
   709 
   710 * HOL/records: generalised field-update to take a function on the
   711 field rather than the new value: r(|A := x|) is translated to A_update
   712 (K x) r The K-combinator that is internally used is called K_record.
   713 INCOMPATIBILITY: Usage of the plain update functions has to be
   714 adapted.
   715  
   716 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   717 0 * x = 0, which are required for a semiring.  Richer structures do
   718 not inherit from semiring_0 anymore, because this property is a
   719 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   720 semiring_0, there is more to prove, but this is mostly trivial.
   721 
   722 * axclass "recpower" was generalized to arbitrary monoids, not just
   723 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   724 commutativity or a semiring property, add the corresponding classes.
   725 
   726 * Unified locale partial_order with class definition (cf. theory
   727 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   728 
   729 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   730 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   731 Isar level, use abbreviations instead.
   732 
   733 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   734 rarely occuring name references (e.g. ``List.op mem.simps'') require
   735 renaming (e.g. ``List.memberl.simps'').
   736 
   737 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   738 INCOMPATIBILITY.
   739 
   740 * Added theory Code_Generator providing class 'eq', allowing for code
   741 generation with polymorphic equality.
   742 
   743 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   744 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   745 significant changes for setting up numeral syntax for types:
   746 
   747   - new constants Numeral.pred and Numeral.succ instead
   748       of former Numeral.bin_pred and Numeral.bin_succ.
   749   - Use integer operations instead of bin_add, bin_mult and so on.
   750   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   751   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   752 
   753 See HOL/Integ/IntArith.thy for an example setup.
   754 
   755 * New top level command 'normal_form' computes the normal form of a
   756 term that may contain free variables. For example ``normal_form
   757 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   758 suitable for heavy-duty computations because the functions are
   759 compiled to ML first.
   760 
   761 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   762 25 like -->); output depends on the "iff" print_mode, the default is
   763 "A = B" (with priority 50).
   764 
   765 * Renamed constants in HOL.thy and Orderings.thy:
   766     op +   ~> HOL.plus_class.plus
   767     op -   ~> HOL.minus_class.minus
   768     uminus ~> HOL.minus_class.uminus
   769     op *   ~> HOL.times_class.times
   770     op <   ~> Orderings.ord_class.less
   771     op <=  ~> Orderings.ord_class.less_eq
   772 
   773 Adaptions may be required in the following cases:
   774 
   775 a) User-defined constants using any of the names "plus", "minus", "times",
   776 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   777 may go wrong.
   778 INCOMPATIBILITY: use more specific names.
   779 
   780 b) Variables named "plus", "minus", "times", "less", "less_eq"
   781 INCOMPATIBILITY: use more specific names.
   782 
   783 c) Permutative equations (e.g. "a + b = b + a")
   784 Since the change of names also changes the order of terms, permutative
   785 rewrite rules may get applied in a different order. Experience shows that
   786 this is rarely the case (only two adaptions in the whole Isabelle
   787 distribution).
   788 INCOMPATIBILITY: rewrite proofs
   789 
   790 d) ML code directly refering to constant names
   791 This in general only affects hand-written proof tactics, simprocs and so on.
   792 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   793 of const_name ML antiquotations.
   794 
   795 * Relations less (<) and less_eq (<=) are also available on type bool.
   796 Modified syntax to disallow nesting without explicit parentheses,
   797 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   798 
   799 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   800 
   801 * Relation composition operator "op O" now has precedence 75 and binds
   802 stronger than union and intersection. INCOMPATIBILITY.
   803 
   804 * The old set interval syntax "{m..n(}" (and relatives) has been
   805 removed.  Use "{m..<n}" (and relatives) instead.
   806 
   807 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   808 "t = s" to False (by simproc "neq_simproc").  For backward
   809 compatibility this can be disabled by ML "reset use_neq_simproc".
   810 
   811 * "m dvd n" where m and n are numbers is evaluated to True/False by
   812 simp.
   813 
   814 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   815 
   816 * Theorem setsum_mult renamed to setsum_right_distrib.
   817 
   818 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   819 ``rule'' method.
   820 
   821 * Reimplemented methods ``sat'' and ``satx'', with several
   822 improvements: goals no longer need to be stated as "<prems> ==>
   823 False", equivalences (i.e. "=" on type bool) are handled, variable
   824 names of the form "lit_<n>" are no longer reserved, significant
   825 speedup.
   826 
   827 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   828 zChaff is still supported as well.
   829 
   830 * 'inductive' and 'datatype': provide projections of mutual rules,
   831 bundled as foo_bar.inducts;
   832 
   833 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   834 Library.
   835 
   836 * Library: moved theory Accessible_Part to main HOL.
   837 
   838 * Library: added theory Coinductive_List of potentially infinite lists
   839 as greatest fixed-point.
   840 
   841 * Library: added theory AssocList which implements (finite) maps as
   842 association lists.
   843 
   844 * Added proof method ``evaluation'' for efficiently solving a goal
   845 (i.e. a boolean expression) by compiling it to ML. The goal is
   846 "proved" (via an oracle) if it evaluates to True.
   847 
   848 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   849 also when invoked by the simplifier.  This results in the simplifier
   850 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   851 fast_arith_split_limit to 0 to obtain the old behavior.
   852 
   853 * Support for hex (0x20) and binary (0b1001) numerals.
   854 
   855 * New method: reify eqs (t), where eqs are equations for an
   856 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   857 parameter, computes a term s::'b and a list xs::'a list and proves the
   858 theorem I xs s = t. This is also known as reification or quoting. The
   859 resulting theorem is applied to the subgoal to substitute t with I xs
   860 s.  If t is omitted, the subgoal itself is reified.
   861 
   862 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   863 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   864 where f is supposed to be a computable function (in the sense of code
   865 generattion). The method uses reify to compute s and xs as above then
   866 applies corr_thm and uses normalization by evaluation to "prove" f s =
   867 r and finally gets the theorem t = r, which is again applied to the
   868 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   869 
   870 * Reflection: Automatic refification now handels binding, an example
   871 is available in HOL/ex/ReflectionEx.thy
   872 
   873 
   874 *** HOL-Algebra ***
   875 
   876 * Formalisation of ideals and the quotient construction over rings.
   877 
   878 * Order and lattice theory no longer based on records.
   879 INCOMPATIBILITY.
   880 
   881 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   882 greatest_closed.  INCOMPATIBILITY.
   883 
   884 * Method algebra is now set up via an attribute.  For examples see
   885 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   886 of algebraic structures.
   887 
   888 * Renamed theory CRing to Ring.
   889 
   890 
   891 *** HOL-Complex ***
   892 
   893 * Theory Real: new method ferrack implements quantifier elimination
   894 for linear arithmetic over the reals. The quantifier elimination
   895 feature is used only for decision, for compatibility with arith. This
   896 means a goal is either solved or left unchanged, no simplification.
   897 
   898 * Hyperreal: Functions root and sqrt are now defined on negative real
   899 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
   900 Nonnegativity side conditions have been removed from many lemmas, so
   901 that more subgoals may now be solved by simplification; potential
   902 INCOMPATIBILITY.
   903 
   904 * Real: New axiomatic classes formalize real normed vector spaces and
   905 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   906 and norm :: 'a => real.
   907 
   908 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   909 from reals into other types. The overloaded constant Reals :: 'a set
   910 is now defined as range of_real; potential INCOMPATIBILITY.
   911 
   912 * Real: ML code generation is supported now and hence also quickcheck.
   913 Reals are implemented as arbitrary precision rationals.
   914 
   915 * Hyperreal: Several constants that previously worked only for the
   916 reals have been generalized, so they now work over arbitrary vector
   917 spaces. Type annotations may need to be added in some cases; potential
   918 INCOMPATIBILITY.
   919 
   920   Infinitesimal  :: ('a::real_normed_vector) star set
   921   HFinite        :: ('a::real_normed_vector) star set
   922   HInfinite      :: ('a::real_normed_vector) star set
   923   approx         :: ('a::real_normed_vector) star => 'a star => bool
   924   monad          :: ('a::real_normed_vector) star => 'a star set
   925   galaxy         :: ('a::real_normed_vector) star => 'a star set
   926   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
   927   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   928   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   929   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   930   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   931   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   932   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   933   sgn            :: 'a::real_normed_vector => 'a
   934   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
   935 
   936 * Complex: Some complex-specific constants are now abbreviations for
   937 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   938 hnorm.  Other constants have been entirely removed in favor of the
   939 polymorphic versions (INCOMPATIBILITY):
   940 
   941   approx        <-- capprox
   942   HFinite       <-- CFinite
   943   HInfinite     <-- CInfinite
   944   Infinitesimal <-- CInfinitesimal
   945   monad         <-- cmonad
   946   galaxy        <-- cgalaxy
   947   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   948   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   949   (ns)deriv     <-- (ns)cderiv
   950 
   951 
   952 *** ML ***
   953 
   954 * Context data interfaces (Theory/Proof/GenericDataFun): removed
   955 name/print, uninitialized data defaults to ad-hoc copy of empty value,
   956 init only required for impure data.  INCOMPATIBILITY: empty really
   957 need to be empty (no dependencies on theory content!)
   958 
   959 * ML within Isar: antiquotations allow to embed statically-checked
   960 formal entities in the source, referring to the context available at
   961 compile-time.  For example:
   962 
   963 ML {* @{typ "'a => 'b"} *}
   964 ML {* @{term "%x. x"} *}
   965 ML {* @{prop "x == y"} *}
   966 ML {* @{ctyp "'a => 'b"} *}
   967 ML {* @{cterm "%x. x"} *}
   968 ML {* @{cprop "x == y"} *}
   969 ML {* @{thm asm_rl} *}
   970 ML {* @{thms asm_rl} *}
   971 ML {* @{const_name c} *}
   972 ML {* @{const_syntax c} *}
   973 ML {* @{context} *}
   974 ML {* @{theory} *}
   975 ML {* @{theory Pure} *}
   976 ML {* @{simpset} *}
   977 ML {* @{claset} *}
   978 ML {* @{clasimpset} *}
   979 
   980 The same works for sources being ``used'' within an Isar context.
   981 
   982 * ML in Isar: improved error reporting; extra verbosity with
   983 Toplevel.debug enabled.
   984 
   985 * Pure/library:
   986 
   987   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   988   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   989 
   990 The semantics of "burrow" is: "take a function with *simulatanously*
   991 transforms a list of value, and apply it *simulatanously* to a list of
   992 list of values of the appropriate type". Compare this with "map" which
   993 would *not* apply its argument function simulatanously but in
   994 sequence; "fold_burrow" has an additional context.
   995 
   996 * Pure/library: functions map2 and fold2 with curried syntax for
   997 simultanous mapping and folding:
   998 
   999     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1000     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1001 
  1002 * Pure/library: indexed lists - some functions in the Isabelle library
  1003 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1004 given more convenient names and signatures reminiscent of similar
  1005 functions for alists, tables, etc:
  1006 
  1007   val nth: 'a list -> int -> 'a 
  1008   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1009   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1010 
  1011 Note that fold_index starts counting at index 0, not 1 like foldln
  1012 used to.
  1013 
  1014 * Pure/library: added general ``divide_and_conquer'' combinator on
  1015 lists.
  1016 
  1017 * Pure/General/table.ML: the join operations now works via exceptions
  1018 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1019 admits slightly more efficient complex applications.
  1020 
  1021 * Pure: datatype Context.generic joins theory/Proof.context and
  1022 provides some facilities for code that works in either kind of
  1023 context, notably GenericDataFun for uniform theory and proof data.
  1024 
  1025 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1026 use Context.generic instead of just theory.
  1027 
  1028 * Pure: simplified internal attribute type, which is now always
  1029 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1030 vs. local (Proof.context) attributes have been discontinued, while
  1031 minimizing code duplication.  Thm.rule_attribute and
  1032 Thm.declaration_attribute build canonical attributes; see also
  1033 structure Context for further operations on Context.generic, notably
  1034 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1035 declarations and definitions.
  1036 
  1037 * Pure/kernel: consts certification ignores sort constraints given in
  1038 signature declarations.  (This information is not relevant to the
  1039 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1040 potential INCOMPATIBILITY.
  1041 
  1042 * Pure: axiomatic type classes are now purely definitional, with
  1043 explicit proofs of class axioms and super class relations performed
  1044 internally.  See Pure/axclass.ML for the main internal interfaces --
  1045 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1046 AxClass.axiomatize_class/classrel/arity supercede
  1047 Sign.add_classes/classrel/arities.
  1048 
  1049 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1050 global/local versions on theory vs. Proof.context have been
  1051 discontinued; Attrib.syntax and Method.syntax have been adapted
  1052 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1053 attributes, methods, etc.
  1054 
  1055 * Pure: several functions of signature "... -> theory -> theory * ..."
  1056 have been reoriented to "... -> theory -> ... * theory" in order to
  1057 allow natural usage in combination with the ||>, ||>>, |-> and
  1058 fold_map combinators.
  1059 
  1060 * Pure: official theorem names (closed derivations) and additional
  1061 comments (tags) are now strictly separate.  Name hints -- which are
  1062 maintained as tags -- may be attached any time without affecting the
  1063 derivation.
  1064 
  1065 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1066 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1067 achieve the old behaviour.
  1068 
  1069 * Pure: the "Goal" constant is now called "prop", supporting a
  1070 slightly more general idea of ``protecting'' meta-level rule
  1071 statements.
  1072 
  1073 * Pure: Logic.(un)varify only works in a global context, which is now
  1074 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1075 Logic.legacy_(un)varify as temporary workaround.
  1076 
  1077 * Pure: structure Name provides scalable operations for generating
  1078 internal variable names, notably Name.variants etc.  This replaces
  1079 some popular functions from term.ML:
  1080 
  1081   Term.variant		->  Name.variant
  1082   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1083   Term.invent_names	->  Name.invent_list
  1084 
  1085 Note that low-level renaming rarely occurs in new code -- operations
  1086 from structure Variable are used instead (see below).
  1087 
  1088 * Pure: structure Variable provides fundamental operations for proper
  1089 treatment of fixed/schematic variables in a context.  For example,
  1090 Variable.import introduces fixes for schematics of given facts and
  1091 Variable.export reverses the effect (up to renaming) -- this replaces
  1092 various freeze_thaw operations.
  1093 
  1094 * Pure: structure Goal provides simple interfaces for
  1095 init/conclude/finish and tactical prove operations (replacing former
  1096 Tactic.prove).  Goal.prove is the canonical way to prove results
  1097 within a given context; Goal.prove_global is a degraded version for
  1098 theory level goals, including a global Drule.standard.  Note that
  1099 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1100 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1101 in a locale context).
  1102 
  1103 * Isar: simplified treatment of user-level errors, using exception
  1104 ERROR of string uniformly.  Function error now merely raises ERROR,
  1105 without any side effect on output channels.  The Isar toplevel takes
  1106 care of proper display of ERROR exceptions.  ML code may use plain
  1107 handle/can/try; cat_error may be used to concatenate errors like this:
  1108 
  1109   ... handle ERROR msg => cat_error msg "..."
  1110 
  1111 Toplevel ML code (run directly or through the Isar toplevel) may be
  1112 embedded into the Isar toplevel with exception display/debug like
  1113 this:
  1114 
  1115   Isar.toplevel (fn () => ...)
  1116 
  1117 INCOMPATIBILITY, removed special transform_error facilities, removed
  1118 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1119 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1120 -- use plain ERROR instead.
  1121 
  1122 * Isar: theory setup now has type (theory -> theory), instead of a
  1123 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1124 
  1125 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1126 subject to ProofContext.debug/verbose flags.
  1127 
  1128 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1129 theory before entering a proof state.  Transactions now always see a
  1130 quasi-functional intermediate checkpoint, both in interactive and
  1131 batch mode.
  1132 
  1133 * Simplifier: the simpset of a running simplification process now
  1134 contains a proof context (cf. Simplifier.the_context), which is the
  1135 very context that the initial simpset has been retrieved from (by
  1136 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1137 (solver, looper etc.) may depend on arbitrary proof data.
  1138 
  1139 * Simplifier.inherit_context inherits the proof context (plus the
  1140 local bounds) of the current simplification process; any simproc
  1141 etc. that calls the Simplifier recursively should do this!  Removed
  1142 former Simplifier.inherit_bounds, which is already included here --
  1143 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1144 specify an explicit context using Simplifier.context/theory_context.
  1145 
  1146 * Simplifier/Classical Reasoner: more abstract interfaces
  1147 change_simpset/claset for modifying the simpset/claset reference of a
  1148 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1149 INCOMPATIBILITY.
  1150 
  1151 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1152 "Trueprop" etc.
  1153 
  1154 
  1155 *** System ***
  1156 
  1157 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1158 locations -- now includes the Isabelle version identifier as well.
  1159 This simplifies use of multiple Isabelle installations.
  1160 
  1161 * isabelle-process: option -S (secure mode) disables some critical
  1162 operations, notably runtime compilation and evaluation of ML source
  1163 code.
  1164 
  1165 
  1166 New in Isabelle2005 (October 2005)
  1167 ----------------------------------
  1168 
  1169 *** General ***
  1170 
  1171 * Theory headers: the new header syntax for Isar theories is
  1172 
  1173   theory <name>
  1174   imports <theory1> ... <theoryN>
  1175   uses <file1> ... <fileM>
  1176   begin
  1177 
  1178 where the 'uses' part is optional.  The previous syntax
  1179 
  1180   theory <name> = <theory1> + ... + <theoryN>:
  1181 
  1182 will disappear in the next release.  Use isatool fixheaders to convert
  1183 existing theory files.  Note that there is no change in ancient
  1184 non-Isar theories now, but these will disappear soon.
  1185 
  1186 * Theory loader: parent theories can now also be referred to via
  1187 relative and absolute paths.
  1188 
  1189 * Command 'find_theorems' searches for a list of criteria instead of a
  1190 list of constants. Known criteria are: intro, elim, dest, name:string,
  1191 simp:term, and any term. Criteria can be preceded by '-' to select
  1192 theorems that do not match. Intro, elim, dest select theorems that
  1193 match the current goal, name:s selects theorems whose fully qualified
  1194 name contain s, and simp:term selects all simplification rules whose
  1195 lhs match term.  Any other term is interpreted as pattern and selects
  1196 all theorems matching the pattern. Available in ProofGeneral under
  1197 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1198 
  1199   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1200 
  1201 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1202 matching the current goal as introduction rule and not having "HOL."
  1203 in their name (i.e. not being defined in theory HOL).
  1204 
  1205 * Command 'thms_containing' has been discontinued in favour of
  1206 'find_theorems'; INCOMPATIBILITY.
  1207 
  1208 * Communication with Proof General is now 8bit clean, which means that
  1209 Unicode text in UTF-8 encoding may be used within theory texts (both
  1210 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1211 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1212 
  1213   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1214   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1215 
  1216 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1217 Classical Reasoner.  Typical big applications run around 2 times
  1218 faster.
  1219 
  1220 
  1221 *** Document preparation ***
  1222 
  1223 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1224 of raw sources.  Only those symbols that do not require additional
  1225 LaTeX packages (depending on comments in isabellesym.sty) are
  1226 displayed properly, everything else is left verbatim.  isatool display
  1227 and isatool print are used as front ends (these are subject to the
  1228 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1229 
  1230 * Command tags control specific markup of certain regions of text,
  1231 notably folding and hiding.  Predefined tags include "theory" (for
  1232 theory begin and end), "proof" for proof commands, and "ML" for
  1233 commands involving ML code; the additional tags "visible" and
  1234 "invisible" are unused by default.  Users may give explicit tag
  1235 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1236 interpretation of tags is determined by the LaTeX job during document
  1237 preparation: see option -V of isatool usedir, or options -n and -t of
  1238 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1239 \isadroptag.
  1240 
  1241 Several document versions may be produced at the same time via isatool
  1242 usedir (the generated index.html will link all of them).  Typical
  1243 specifications include ''-V document=theory,proof,ML'' to present
  1244 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1245 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1246 these parts without any formal replacement text.  The Isabelle site
  1247 default settings produce ''document'' and ''outline'' versions as
  1248 specified above.
  1249 
  1250 * Several new antiquotations:
  1251 
  1252   @{term_type term} prints a term with its type annotated;
  1253 
  1254   @{typeof term} prints the type of a term;
  1255 
  1256   @{const const} is the same as @{term const}, but checks that the
  1257   argument is a known logical constant;
  1258 
  1259   @{term_style style term} and @{thm_style style thm} print a term or
  1260   theorem applying a "style" to it
  1261 
  1262   @{ML text}
  1263 
  1264 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1265 definitions, equations, inequations etc., 'concl' printing only the
  1266 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1267 to print the specified premise.  TermStyle.add_style provides an ML
  1268 interface for introducing further styles.  See also the "LaTeX Sugar"
  1269 document practical applications.  The ML antiquotation prints
  1270 type-checked ML expressions verbatim.
  1271 
  1272 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1273 and 'text' support optional locale specification '(in loc)', which
  1274 specifies the default context for interpreting antiquotations.  For
  1275 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1276 
  1277 * Option 'locale=NAME' of antiquotations specifies an alternative
  1278 context interpreting the subsequent argument.  For example: @{thm
  1279 [locale=lattice] inf_assoc}.
  1280 
  1281 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1282 a proof context.
  1283 
  1284 * Proper output of antiquotations for theory commands involving a
  1285 proof context (such as 'locale' or 'theorem (in loc) ...').
  1286 
  1287 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1288 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1289 
  1290 * isatool usedir: new option -C (default true) controls whether option
  1291 -D should include a copy of the original document directory; -C false
  1292 prevents unwanted effects such as copying of administrative CVS data.
  1293 
  1294 
  1295 *** Pure ***
  1296 
  1297 * Considerably improved version of 'constdefs' command.  Now performs
  1298 automatic type-inference of declared constants; additional support for
  1299 local structure declarations (cf. locales and HOL records), see also
  1300 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1301 sequential dependencies of definitions within a single 'constdefs'
  1302 section; moreover, the declared name needs to be an identifier.  If
  1303 all fails, consider to fall back on 'consts' and 'defs' separately.
  1304 
  1305 * Improved indexed syntax and implicit structures.  First of all,
  1306 indexed syntax provides a notational device for subscripted
  1307 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1308 expressions.  Secondly, in a local context with structure
  1309 declarations, number indexes \<^sub>n or the empty index (default
  1310 number 1) refer to a certain fixed variable implicitly; option
  1311 show_structs controls printing of implicit structures.  Typical
  1312 applications of these concepts involve record types and locales.
  1313 
  1314 * New command 'no_syntax' removes grammar declarations (and
  1315 translations) resulting from the given syntax specification, which is
  1316 interpreted in the same manner as for the 'syntax' command.
  1317 
  1318 * 'Advanced' translation functions (parse_translation etc.) may depend
  1319 on the signature of the theory context being presently used for
  1320 parsing/printing, see also isar-ref manual.
  1321 
  1322 * Improved 'oracle' command provides a type-safe interface to turn an
  1323 ML expression of type theory -> T -> term into a primitive rule of
  1324 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1325 is already included here); see also FOL/ex/IffExample.thy;
  1326 INCOMPATIBILITY.
  1327 
  1328 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1329 before); "cI" is no longer bound, use "c.intro" instead.
  1330 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1331 axclasses vs. locales.
  1332 
  1333 * Improved internal renaming of symbolic identifiers -- attach primes
  1334 instead of base 26 numbers.
  1335 
  1336 * New flag show_question_marks controls printing of leading question
  1337 marks in schematic variable names.
  1338 
  1339 * In schematic variable names, *any* symbol following \<^isub> or
  1340 \<^isup> is now treated as part of the base name.  For example, the
  1341 following works without printing of awkward ".0" indexes:
  1342 
  1343   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1344     by simp
  1345 
  1346 * Inner syntax includes (*(*nested*) comments*).
  1347 
  1348 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1349 annotations as "(00...)".
  1350 
  1351 * Clear separation of logical types and nonterminals, where the latter
  1352 may only occur in 'syntax' specifications or type abbreviations.
  1353 Before that distinction was only partially implemented via type class
  1354 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1355 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1356 exotic syntax specifications may require further adaption
  1357 (e.g. Cube/Cube.thy).
  1358 
  1359 * Removed obsolete type class "logic", use the top sort {} instead.
  1360 Note that non-logical types should be declared as 'nonterminals'
  1361 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1362 specifications.
  1363 
  1364 * Attributes 'induct' and 'cases': type or set names may now be
  1365 locally fixed variables as well.
  1366 
  1367 * Simplifier: can now control the depth to which conditional rewriting
  1368 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1369 Limit.
  1370 
  1371 * Simplifier: simplification procedures may now take the current
  1372 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1373 interface), which is very useful for calling the Simplifier
  1374 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1375 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1376 low-level mk_simproc no longer applies Logic.varify internally, to
  1377 allow for use in a context of fixed variables.
  1378 
  1379 * thin_tac now works even if the assumption being deleted contains !!
  1380 or ==>.  More generally, erule now works even if the major premise of
  1381 the elimination rule contains !! or ==>.
  1382 
  1383 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1384 
  1385 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1386 from Pure, which contains all common declarations already.  Both
  1387 theories are defined via plain Isabelle/Isar .thy files.
  1388 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1389 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1390 use isatool fixcpure to adapt your theory and ML sources.
  1391 
  1392 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1393 selections of theorems in named facts via index ranges.
  1394 
  1395 * 'print_theorems': in theory mode, really print the difference
  1396 wrt. the last state (works for interactive theory development only),
  1397 in proof mode print all local facts (cf. 'print_facts');
  1398 
  1399 * 'hide': option '(open)' hides only base names.
  1400 
  1401 * More efficient treatment of intermediate checkpoints in interactive
  1402 theory development.
  1403 
  1404 * Code generator is now invoked via code_module (incremental code
  1405 generation) and code_library (modular code generation, ML structures
  1406 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1407 must be quoted when used as identifiers.
  1408 
  1409 * New 'value' command for reading, evaluating and printing terms using
  1410 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1411 quoted when used as identifier.
  1412 
  1413 
  1414 *** Locales ***
  1415 
  1416 * New commands for the interpretation of locale expressions in
  1417 theories (1), locales (2) and proof contexts (3).  These generate
  1418 proof obligations from the expression specification.  After the
  1419 obligations have been discharged, theorems of the expression are added
  1420 to the theory, target locale or proof context.  The synopsis of the
  1421 commands is a follows:
  1422 
  1423   (1) interpretation expr inst
  1424   (2) interpretation target < expr
  1425   (3) interpret expr inst
  1426 
  1427 Interpretation in theories and proof contexts require a parameter
  1428 instantiation of terms from the current context.  This is applied to
  1429 specifications and theorems of the interpreted expression.
  1430 Interpretation in locales only permits parameter renaming through the
  1431 locale expression.  Interpretation is smart in that interpretations
  1432 that are active already do not occur in proof obligations, neither are
  1433 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1434 inspect active interpretations of a particular locale.  For details,
  1435 see the Isar Reference manual.  Examples can be found in
  1436 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1437 
  1438 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1439 'interpret' instead.
  1440 
  1441 * New context element 'constrains' for adding type constraints to
  1442 parameters.
  1443 
  1444 * Context expressions: renaming of parameters with syntax
  1445 redeclaration.
  1446 
  1447 * Locale declaration: 'includes' disallowed.
  1448 
  1449 * Proper static binding of attribute syntax -- i.e. types / terms /
  1450 facts mentioned as arguments are always those of the locale definition
  1451 context, independently of the context of later invocations.  Moreover,
  1452 locale operations (renaming and type / term instantiation) are applied
  1453 to attribute arguments as expected.
  1454 
  1455 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1456 actual attributes; rare situations may require Attrib.attribute to
  1457 embed those attributes into Attrib.src that lack concrete syntax.
  1458 Attribute implementations need to cooperate properly with the static
  1459 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1460 Attrib.XXX_thm etc. already do the right thing without further
  1461 intervention.  Only unusual applications -- such as "where" or "of"
  1462 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1463 on the context and the facts involved -- may have to assign parsed
  1464 values to argument tokens explicitly.
  1465 
  1466 * Changed parameter management in theorem generation for long goal
  1467 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1468 theorem statement in rare situations.
  1469 
  1470 * Locale inspection command 'print_locale' omits notes elements.  Use
  1471 'print_locale!' to have them included in the output.
  1472 
  1473 
  1474 *** Provers ***
  1475 
  1476 * Provers/hypsubst.ML: improved version of the subst method, for
  1477 single-step rewriting: it now works in bound variable contexts. New is
  1478 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1479 rewrite a different subterm than the original subst method, which is
  1480 still available as 'simplesubst'.
  1481 
  1482 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1483 and quasi orders.
  1484 
  1485 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1486 reflexive-transitive closure of relations.
  1487 
  1488 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1489 limit (previously hard-coded with a value of 20) user-definable.
  1490 
  1491 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1492 is peformed already.  Object-logics merely need to finish their
  1493 initial simpset configuration as before.  INCOMPATIBILITY.
  1494 
  1495 
  1496 *** HOL ***
  1497 
  1498 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1499 
  1500   syntax (epsilon)
  1501     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1502 
  1503 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1504 and x-symbol; use option '-m epsilon' to get it actually printed.
  1505 Moreover, the mathematically important symbolic identifier \<epsilon>
  1506 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1507 
  1508 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1509 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1510 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1511 support corresponding Isar calculations.
  1512 
  1513 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1514 instead of ":".
  1515 
  1516 * theory SetInterval: changed the syntax for open intervals:
  1517 
  1518   Old       New
  1519   {..n(}    {..<n}
  1520   {)n..}    {n<..}
  1521   {m..n(}   {m..<n}
  1522   {)m..n}   {m<..n}
  1523   {)m..n(}  {m<..<n}
  1524 
  1525 The old syntax is still supported but will disappear in the next
  1526 release.  For conversion use the following Emacs search and replace
  1527 patterns (these are not perfect but work quite well):
  1528 
  1529   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1530   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1531 
  1532 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1533 equalities in commutative rings; method 'algebra' provides a generic
  1534 interface.
  1535 
  1536 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1537 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1538 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1539 be a tuple pattern.
  1540 
  1541 Some new syntax forms are available:
  1542 
  1543   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1544   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1545   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1546   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1547 
  1548 The latter form "\<Sum>x < k. e" used to be based on a separate
  1549 function "Summation", which has been discontinued.
  1550 
  1551 * theory Finite_Set: in structured induction proofs, the insert case
  1552 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1553 (insert F x)'.
  1554 
  1555 * The 'refute' command has been extended to support a much larger
  1556 fragment of HOL, including axiomatic type classes, constdefs and
  1557 typedefs, inductive datatypes and recursion.
  1558 
  1559 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1560 Requires zChaff with proof generation to be installed.  See
  1561 HOL/ex/SAT_Examples.thy for examples.
  1562 
  1563 * Datatype induction via method 'induct' now preserves the name of the
  1564 induction variable. For example, when proving P(xs::'a list) by
  1565 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1566 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1567 in unstructured proof scripts.
  1568 
  1569 * Reworked implementation of records.  Improved scalability for
  1570 records with many fields, avoiding performance problems for type
  1571 inference. Records are no longer composed of nested field types, but
  1572 of nested extension types. Therefore the record type only grows linear
  1573 in the number of extensions and not in the number of fields.  The
  1574 top-level (users) view on records is preserved.  Potential
  1575 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1576 old record representation. The type generated for a record is called
  1577 <record_name>_ext_type.
  1578 
  1579 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1580 proofs triggered by a record definition or a simproc (if
  1581 quick_and_dirty is enabled).  Definitions of large records can take
  1582 quite long.
  1583 
  1584 New simproc record_upd_simproc for simplification of multiple record
  1585 updates enabled by default.  Moreover, trivial updates are also
  1586 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1587 occasionally, since simplification is more powerful by default.
  1588 
  1589 * typedef: proper support for polymorphic sets, which contain extra
  1590 type-variables in the term.
  1591 
  1592 * Simplifier: automatically reasons about transitivity chains
  1593 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1594 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1595 old proofs break occasionally as simplification may now solve more
  1596 goals than previously.
  1597 
  1598 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1599 present.  Works for all partial orders (class "order"), in particular
  1600 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1601 just like y <= x.
  1602 
  1603 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1604 bound variable or a constant then the let is unfolded.  Otherwise
  1605 first a is simplified to b, and then f b is simplified to g. If
  1606 possible we abstract b from g arriving at "let x = b in h x",
  1607 otherwise we unfold the let and arrive at g.  The simproc can be
  1608 enabled/disabled by the reference use_let_simproc.  Potential
  1609 INCOMPATIBILITY since simplification is more powerful by default.
  1610 
  1611 * Classical reasoning: the meson method now accepts theorems as arguments.
  1612 
  1613 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1614 jobs to provide advice on the provability of subgoals.
  1615 
  1616 * Theory OrderedGroup and Ring_and_Field: various additions and
  1617 improvements to faciliate calculations involving equalities and
  1618 inequalities.
  1619 
  1620 The following theorems have been eliminated or modified
  1621 (INCOMPATIBILITY):
  1622 
  1623   abs_eq             now named abs_of_nonneg
  1624   abs_of_ge_0        now named abs_of_nonneg
  1625   abs_minus_eq       now named abs_of_nonpos
  1626   imp_abs_id         now named abs_of_nonneg
  1627   imp_abs_neg_id     now named abs_of_nonpos
  1628   mult_pos           now named mult_pos_pos
  1629   mult_pos_le        now named mult_nonneg_nonneg
  1630   mult_pos_neg_le    now named mult_nonneg_nonpos
  1631   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1632   mult_neg           now named mult_neg_neg
  1633   mult_neg_le        now named mult_nonpos_nonpos
  1634 
  1635 * Theory Parity: added rules for simplifying exponents.
  1636 
  1637 * Theory List:
  1638 
  1639 The following theorems have been eliminated or modified
  1640 (INCOMPATIBILITY):
  1641 
  1642   list_all_Nil       now named list_all.simps(1)
  1643   list_all_Cons      now named list_all.simps(2)
  1644   list_all_conv      now named list_all_iff
  1645   set_mem_eq         now named mem_iff
  1646 
  1647 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1648 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1649 
  1650 
  1651 *** HOL-Complex ***
  1652 
  1653 * Theory RealDef: better support for embedding natural numbers and
  1654 integers in the reals.
  1655 
  1656 The following theorems have been eliminated or modified
  1657 (INCOMPATIBILITY):
  1658 
  1659   exp_ge_add_one_self  now requires no hypotheses
  1660   real_of_int_add      reversed direction of equality (use [symmetric])
  1661   real_of_int_minus    reversed direction of equality (use [symmetric])
  1662   real_of_int_diff     reversed direction of equality (use [symmetric])
  1663   real_of_int_mult     reversed direction of equality (use [symmetric])
  1664 
  1665 * Theory RComplete: expanded support for floor and ceiling functions.
  1666 
  1667 * Theory Ln is new, with properties of the natural logarithm
  1668 
  1669 * Hyperreal: There is a new type constructor "star" for making
  1670 nonstandard types.  The old type names are now type synonyms:
  1671 
  1672   hypreal = real star
  1673   hypnat = nat star
  1674   hcomplex = complex star
  1675 
  1676 * Hyperreal: Many groups of similarly-defined constants have been
  1677 replaced by polymorphic versions (INCOMPATIBILITY):
  1678 
  1679   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1680 
  1681   starset      <-- starsetNat, starsetC
  1682   *s*          <-- *sNat*, *sc*
  1683   starset_n    <-- starsetNat_n, starsetC_n
  1684   *sn*         <-- *sNatn*, *scn*
  1685   InternalSets <-- InternalNatSets, InternalCSets
  1686 
  1687   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1688   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1689   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1690   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1691   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1692 
  1693 * Hyperreal: Many type-specific theorems have been removed in favor of
  1694 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1695 
  1696   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1697   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1698   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1699   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1700   right_minus <-- hypreal_add_minus
  1701   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1702   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1703   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1704   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1705   mult_1_right <-- hcomplex_mult_one_right
  1706   mult_zero_left <-- hcomplex_mult_zero_left
  1707   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1708   right_distrib <-- hypnat_add_mult_distrib2
  1709   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1710   right_inverse <-- hypreal_mult_inverse
  1711   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1712   order_refl <-- {hypreal,hypnat}_le_refl
  1713   order_trans <-- {hypreal,hypnat}_le_trans
  1714   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1715   order_less_le <-- {hypreal,hypnat}_less_le
  1716   linorder_linear <-- {hypreal,hypnat}_le_linear
  1717   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1718   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1719   add_nonneg_nonneg <-- hypreal_le_add_order
  1720 
  1721 * Hyperreal: Separate theorems having to do with type-specific
  1722 versions of constants have been merged into theorems that apply to the
  1723 new polymorphic constants (INCOMPATIBILITY):
  1724 
  1725   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1726   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1727   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1728   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1729   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1730   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1731   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1732   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1733   STAR_diff <-- {STAR,STARC}_diff
  1734   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1735     STARC_hcomplex_of_complex}_image_subset
  1736   starset_n_Un <-- starset{Nat,C}_n_Un
  1737   starset_n_Int <-- starset{Nat,C}_n_Int
  1738   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1739   starset_n_diff <-- starset{Nat,C}_n_diff
  1740   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1741   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1742   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1743   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1744   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1745   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1746   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1747   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1748   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1749   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1750   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1751   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1752   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1753   starfun_diff <-- starfun{C,RC,CR}_diff
  1754   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1755   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1756   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1757   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1758   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1759   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1760   starfun_Id <-- starfunC_Id
  1761   starfun_approx <-- starfun{Nat,CR}_approx
  1762   starfun_capprox <-- starfun{C,RC}_capprox
  1763   starfun_abs <-- starfunNat_rabs
  1764   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1765   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1766   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1767   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1768   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1769   starfun_add_approx <-- starfunCR_add_approx
  1770   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1771   starfun_divide <-- starfun{C,CR,RC}_divide
  1772   starfun_n <-- starfun{Nat,C}_n
  1773   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1774   starfun_n_add <-- starfun{Nat,C}_n_add
  1775   starfun_n_add_minus <-- starfunNat_n_add_minus
  1776   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1777   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1778   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1779 
  1780   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1781   star_n_minus <-- {hypreal,hcomplex}_minus
  1782   star_n_diff <-- {hypreal,hcomplex}_diff
  1783   star_n_mult <-- {hypreal,hcomplex}_mult
  1784   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1785   star_n_le <-- {hypreal,hypnat}_le
  1786   star_n_less <-- {hypreal,hypnat}_less
  1787   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1788   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1789   star_n_abs <-- hypreal_hrabs
  1790   star_n_divide <-- hcomplex_divide
  1791 
  1792   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1793   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1794   star_of_diff <-- hypreal_of_real_diff
  1795   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1796   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1797   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1798   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1799   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1800   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1801   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1802   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1803   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1804   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1805   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1806   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1807   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1808   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1809   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1810   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1811   star_of_power <-- hypreal_of_real_power
  1812   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1813 
  1814 * Hyperreal: new method "transfer" that implements the transfer
  1815 principle of nonstandard analysis. With a subgoal that mentions
  1816 nonstandard types like "'a star", the command "apply transfer"
  1817 replaces it with an equivalent one that mentions only standard types.
  1818 To be successful, all free variables must have standard types; non-
  1819 standard variables must have explicit universal quantifiers.
  1820 
  1821 * Hyperreal: A theory of Taylor series.
  1822 
  1823 
  1824 *** HOLCF ***
  1825 
  1826 * Discontinued special version of 'constdefs' (which used to support
  1827 continuous functions) in favor of the general Pure one with full
  1828 type-inference.
  1829 
  1830 * New simplification procedure for solving continuity conditions; it
  1831 is much faster on terms with many nested lambda abstractions (cubic
  1832 instead of exponential time).
  1833 
  1834 * New syntax for domain package: selector names are now optional.
  1835 Parentheses should be omitted unless argument is lazy, for example:
  1836 
  1837   domain 'a stream = cons "'a" (lazy "'a stream")
  1838 
  1839 * New command 'fixrec' for defining recursive functions with pattern
  1840 matching; defining multiple functions with mutual recursion is also
  1841 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1842 sinr, or any data constructor defined by the domain package. The given
  1843 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1844 syntax and examples.
  1845 
  1846 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1847 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1848 but the proof obligation additionally includes an admissibility
  1849 requirement. The packages generate instances of class cpo or pcpo,
  1850 with continuity and strictness theorems for Rep and Abs.
  1851 
  1852 * HOLCF: Many theorems have been renamed according to a more standard naming
  1853 scheme (INCOMPATIBILITY):
  1854 
  1855   foo_inject:  "foo$x = foo$y ==> x = y"
  1856   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1857   foo_less:    "(foo$x << foo$y) = (x << y)"
  1858   foo_strict:  "foo$UU = UU"
  1859   foo_defined: "... ==> foo$x ~= UU"
  1860   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1861 
  1862 
  1863 *** ZF ***
  1864 
  1865 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1866 including the First Isomorphism Theorem (on quotienting by the kernel
  1867 of a homomorphism).
  1868 
  1869 * ZF/Simplifier: install second copy of type solver that actually
  1870 makes use of TC rules declared to Isar proof contexts (or locales);
  1871 the old version is still required for ML proof scripts.
  1872 
  1873 
  1874 *** Cube ***
  1875 
  1876 * Converted to Isar theory format; use locales instead of axiomatic
  1877 theories.
  1878 
  1879 
  1880 *** ML ***
  1881 
  1882 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1883 for ||>, ||>>, |>>,
  1884 
  1885 * Pure/library.ML no longer defines its own option datatype, but uses
  1886 that of the SML basis, which has constructors NONE and SOME instead of
  1887 None and Some, as well as exception Option.Option instead of OPTION.
  1888 The functions the, if_none, is_some, is_none have been adapted
  1889 accordingly, while Option.map replaces apsome.
  1890 
  1891 * Pure/library.ML: the exception LIST has been given up in favour of
  1892 the standard exceptions Empty and Subscript, as well as
  1893 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1894 superceded by the standard hd and tl functions etc.
  1895 
  1896 A number of basic list functions are no longer exported to the ML
  1897 toplevel, as they are variants of predefined functions.  The following
  1898 suggests how one can translate existing code:
  1899 
  1900     rev_append xs ys = List.revAppend (xs, ys)
  1901     nth_elem (i, xs) = List.nth (xs, i)
  1902     last_elem xs = List.last xs
  1903     flat xss = List.concat xss
  1904     seq fs = List.app fs
  1905     partition P xs = List.partition P xs
  1906     mapfilter f xs = List.mapPartial f xs
  1907 
  1908 * Pure/library.ML: several combinators for linear functional
  1909 transformations, notably reverse application and composition:
  1910 
  1911   x |> f                f #> g
  1912   (x, y) |-> f          f #-> g
  1913 
  1914 * Pure/library.ML: introduced/changed precedence of infix operators:
  1915 
  1916   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1917   infix 2 ?;
  1918   infix 3 o oo ooo oooo;
  1919   infix 4 ~~ upto downto;
  1920 
  1921 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1922 infix operators.
  1923 
  1924 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1925 fold_map support linear functional transformations and nesting.  For
  1926 example:
  1927 
  1928   fold f [x1, ..., xN] y =
  1929     y |> f x1 |> ... |> f xN
  1930 
  1931   (fold o fold) f [xs1, ..., xsN] y =
  1932     y |> fold f xs1 |> ... |> fold f xsN
  1933 
  1934   fold f [x1, ..., xN] =
  1935     f x1 #> ... #> f xN
  1936 
  1937   (fold o fold) f [xs1, ..., xsN] =
  1938     fold f xs1 #> ... #> fold f xsN
  1939 
  1940 * Pure/library.ML: the following selectors on type 'a option are
  1941 available:
  1942 
  1943   the:               'a option -> 'a  (*partial*)
  1944   these:             'a option -> 'a  where 'a = 'b list
  1945   the_default: 'a -> 'a option -> 'a
  1946   the_list:          'a option -> 'a list
  1947 
  1948 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1949 basic operations for association lists, following natural argument
  1950 order; moreover the explicit equality predicate passed here avoids
  1951 potentially expensive polymorphic runtime equality checks.
  1952 The old functions may be expressed as follows:
  1953 
  1954   assoc = uncurry (AList.lookup (op =))
  1955   assocs = these oo AList.lookup (op =)
  1956   overwrite = uncurry (AList.update (op =)) o swap
  1957 
  1958 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1959 
  1960   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1961   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1962 
  1963 replacing make_keylist and keyfilter (occassionally used)
  1964 Naive rewrites:
  1965 
  1966   make_keylist = AList.make
  1967   keyfilter = AList.find (op =)
  1968 
  1969 * eq_fst and eq_snd now take explicit equality parameter, thus
  1970   avoiding eqtypes. Naive rewrites:
  1971 
  1972     eq_fst = eq_fst (op =)
  1973     eq_snd = eq_snd (op =)
  1974 
  1975 * Removed deprecated apl and apr (rarely used).
  1976   Naive rewrites:
  1977 
  1978     apl (n, op) =>>= curry op n
  1979     apr (op, m) =>>= fn n => op (n, m)
  1980 
  1981 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1982 provides a reasonably efficient light-weight implementation of sets as
  1983 lists.
  1984 
  1985 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1986 few new operations; existing lookup and update are now curried to
  1987 follow natural argument order (for use with fold etc.);
  1988 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1989 
  1990 * Pure/General: output via the Isabelle channels of
  1991 writeln/warning/error etc. is now passed through Output.output, with a
  1992 hook for arbitrary transformations depending on the print_mode
  1993 (cf. Output.add_mode -- the first active mode that provides a output
  1994 function wins).  Already formatted output may be embedded into further
  1995 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1996 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1997 accommodate easy composition of diagnostic messages etc.  Programmers
  1998 rarely need to care about Output.output or Output.raw at all, with
  1999 some notable exceptions: Output.output is required when bypassing the
  2000 standard channels (writeln etc.), or in token translations to produce
  2001 properly formatted results; Output.raw is required when capturing
  2002 already output material that will eventually be presented to the user
  2003 a second time.  For the default print mode, both Output.output and
  2004 Output.raw have no effect.
  2005 
  2006 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2007 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2008 cumulative results are displayed at the end of a batch session.
  2009 
  2010 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2011 replaced by File.platform_path and File.shell_path (with appropriate
  2012 hooks).  This provides a clean interface for unusual systems where the
  2013 internal and external process view of file names are different.
  2014 
  2015 * Pure: more efficient orders for basic syntactic entities: added
  2016 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2017 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2018 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2019 orders now -- potential INCOMPATIBILITY for code that depends on a
  2020 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2021 Library.sort_strings on result).
  2022 
  2023 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2024 fold_types traverse types/terms from left to right, observing natural
  2025 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2026 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2027 
  2028 * Pure: name spaces have been refined, with significant changes of the
  2029 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2030 to extern(_table).  The plain name entry path is superceded by a
  2031 general 'naming' context, which also includes the 'policy' to produce
  2032 a fully qualified name and external accesses of a fully qualified
  2033 name; NameSpace.extend is superceded by context dependent
  2034 Sign.declare_name.  Several theory and proof context operations modify
  2035 the naming context.  Especially note Theory.restore_naming and
  2036 ProofContext.restore_naming to get back to a sane state; note that
  2037 Theory.add_path is no longer sufficient to recover from
  2038 Theory.absolute_path in particular.
  2039 
  2040 * Pure: new flags short_names (default false) and unique_names
  2041 (default true) for controlling output of qualified names.  If
  2042 short_names is set, names are printed unqualified.  If unique_names is
  2043 reset, the name prefix is reduced to the minimum required to achieve
  2044 the original result when interning again, even if there is an overlap
  2045 with earlier declarations.
  2046 
  2047 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2048 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2049 (useful for printing error messages).  INCOMPATIBILITY.
  2050 
  2051 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2052 Theory.theory are now identified, referring to the universal
  2053 Context.theory (see Pure/context.ML).  Actual signature and theory
  2054 content is managed as theory data.  The old code and interfaces were
  2055 spread over many files and structures; the new arrangement introduces
  2056 considerable INCOMPATIBILITY to gain more clarity:
  2057 
  2058   Context -- theory management operations (name, identity, inclusion,
  2059     parents, ancestors, merge, etc.), plus generic theory data;
  2060 
  2061   Sign -- logical signature and syntax operations (declaring consts,
  2062     types, etc.), plus certify/read for common entities;
  2063 
  2064   Theory -- logical theory operations (stating axioms, definitions,
  2065     oracles), plus a copy of logical signature operations (consts,
  2066     types, etc.); also a few basic management operations (Theory.copy,
  2067     Theory.merge, etc.)
  2068 
  2069 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2070 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2071 for convenience -- they merely return the theory.
  2072 
  2073 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2074 
  2075 * Pure: the Isar proof context type is already defined early in Pure
  2076 as Context.proof (note that ProofContext.context and Proof.context are
  2077 aliases, where the latter is the preferred name).  This enables other
  2078 Isabelle components to refer to that type even before Isar is present.
  2079 
  2080 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2081 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2082 any of these kinds.  For example, Sign.intern typeK is now
  2083 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2084 Theory.hide_types.  Also note that former
  2085 Theory.hide_classes/types/consts are now
  2086 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2087 internalize their arguments!  INCOMPATIBILITY.
  2088 
  2089 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2090 datatype thmref (with constructors Name and NameSelection) instead of
  2091 plain string -- INCOMPATIBILITY;
  2092 
  2093 * Pure: cases produced by proof methods specify options, where NONE
  2094 means to remove case bindings -- INCOMPATIBILITY in
  2095 (RAW_)METHOD_CASES.
  2096 
  2097 * Pure: the following operations retrieve axioms or theorems from a
  2098 theory node or theory hierarchy, respectively:
  2099 
  2100   Theory.axioms_of: theory -> (string * term) list
  2101   Theory.all_axioms_of: theory -> (string * term) list
  2102   PureThy.thms_of: theory -> (string * thm) list
  2103   PureThy.all_thms_of: theory -> (string * thm) list
  2104 
  2105 * Pure: print_tac now outputs the goal through the trace channel.
  2106 
  2107 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2108 Reference Toplevel.debug (default false) controls detailed printing
  2109 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2110 controls execution profiling -- set to 1 for time and 2 for space
  2111 (both increase the runtime).
  2112 
  2113 * Isar session: The initial use of ROOT.ML is now always timed,
  2114 i.e. the log will show the actual process times, in contrast to the
  2115 elapsed wall-clock time that the outer shell wrapper produces.
  2116 
  2117 * Simplifier: improved handling of bound variables (nameless
  2118 representation, avoid allocating new strings).  Simprocs that invoke
  2119 the Simplifier recursively should use Simplifier.inherit_bounds to
  2120 avoid local name clashes.  Failure to do so produces warnings
  2121 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2122 for further details.
  2123 
  2124 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2125 bindings for all theorems stored within a given theory; this may help
  2126 in porting non-Isar theories to Isar ones, while keeping ML proof
  2127 scripts for the time being.
  2128 
  2129 * ML operator HTML.with_charset specifies the charset begin used for
  2130 generated HTML files.  For example:
  2131 
  2132   HTML.with_charset "utf-8" use_thy "Hebrew";
  2133   HTML.with_charset "utf-8" use_thy "Chinese";
  2134 
  2135 
  2136 *** System ***
  2137 
  2138 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2139 isabelle, isatool etc.).
  2140 
  2141 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2142 isatool doc, isatool mkdir, display_drafts etc.).
  2143 
  2144 * isatool usedir: option -f allows specification of the ML file to be
  2145 used by Isabelle; default is ROOT.ML.
  2146 
  2147 * New isatool version outputs the version identifier of the Isabelle
  2148 distribution being used.
  2149 
  2150 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2151 (containing Boolean satisfiability problems) into Isabelle/HOL
  2152 theories.
  2153 
  2154 
  2155 
  2156 New in Isabelle2004 (April 2004)
  2157 --------------------------------
  2158 
  2159 *** General ***
  2160 
  2161 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2162   Replaces linorder.ML.
  2163 
  2164 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2165   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2166   (\<a>...\<z>), are now considered normal letters, and can therefore
  2167   be used anywhere where an ASCII letter (a...zA...Z) has until
  2168   now. COMPATIBILITY: This obviously changes the parsing of some
  2169   terms, especially where a symbol has been used as a binder, say
  2170   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2171   as an identifier.  Fix it by inserting a space around former
  2172   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2173   existing theory and ML files.
  2174 
  2175 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2176 
  2177 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2178   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2179   a normal (but invisible) letter. For multiple letter subscripts repeat
  2180   \<^isub> like this: x\<^isub>1\<^isub>2.
  2181 
  2182 * Pure: There are now sub-/superscripts that can span more than one
  2183   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2184   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2185   superscript. The new control characters are not identifier parts.
  2186 
  2187 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2188   content of "..." to the latex file instead of \isacntrl... . The "..."
  2189   may consist of any printable characters excluding the end bracket >.
  2190 
  2191 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2192   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2193   declare constants "final", which prevents their being given a definition
  2194   later.  It is useful for constants whose behaviour is fixed axiomatically
  2195   rather than definitionally, such as the meta-logic connectives.
  2196 
  2197 * Pure: 'instance' now handles general arities with general sorts
  2198   (i.e. intersections of classes),
  2199 
  2200 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2201   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2202   It can be changed to alter the colors/layout of generated pages.
  2203 
  2204 
  2205 *** Isar ***
  2206 
  2207 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2208   cut_tac, subgoal_tac and thin_tac:
  2209   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2210     locales are no longer forced to write Isar proof scripts.
  2211     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2212     emulations.
  2213   - INCOMPATIBILITY: names of variables to be instantiated may no
  2214     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2215     This is consistent with the instantiation attribute "where".
  2216 
  2217 * Attributes "where" and "of":
  2218   - Now take type variables of instantiated theorem into account when reading
  2219     the instantiation string.  This fixes a bug that caused instantiated
  2220     theorems to have too special types in some circumstances.
  2221   - "where" permits explicit instantiations of type variables.
  2222 
  2223 * Calculation commands "moreover" and "also" no longer interfere with
  2224   current facts ("this"), admitting arbitrary combinations with "then"
  2225   and derived forms.
  2226 
  2227 * Locales:
  2228   - Goal statements involving the context element "includes" no longer
  2229     generate theorems with internal delta predicates (those ending on
  2230     "_axioms") in the premise.
  2231     Resolve particular premise with <locale>.intro to obtain old form.
  2232   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2233     specification and "includes" elements in goal statement.
  2234   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2235     [intro?] and [elim?] (respectively) by default.
  2236   - Experimental command for instantiation of locales in proof contexts:
  2237         instantiate <label>[<attrs>]: <loc>
  2238     Instantiates locale <loc> and adds all its theorems to the current context
  2239     taking into account their attributes.  Label and attrs are optional
  2240     modifiers, like in theorem declarations.  If present, names of
  2241     instantiated theorems are qualified with <label>, and the attributes
  2242     <attrs> are applied after any attributes these theorems might have already.
  2243       If the locale has assumptions, a chained fact of the form
  2244     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2245     are derived.  The command does not support old-style locales declared
  2246     with "locale (open)".
  2247       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2248 
  2249 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2250   (Isar) contexts.
  2251 
  2252 
  2253 *** HOL ***
  2254 
  2255 * Proof import: new image HOL4 contains the imported library from
  2256   the HOL4 system with about 2500 theorems. It is imported by
  2257   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2258   can be used like any other Isabelle image.  See
  2259   HOL/Import/HOL/README for more information.
  2260 
  2261 * Simplifier:
  2262   - Much improved handling of linear and partial orders.
  2263     Reasoners for linear and partial orders are set up for type classes
  2264     "linorder" and "order" respectively, and are added to the default simpset
  2265     as solvers.  This means that the simplifier can build transitivity chains
  2266     to solve goals from the assumptions.
  2267   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2268     of blast or auto after simplification become unnecessary because the goal
  2269     is solved by simplification already.
  2270 
  2271 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2272     all proved in axiomatic type classes for semirings, rings and fields.
  2273 
  2274 * Numerics:
  2275   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2276     now formalized using the Ring_and_Field theory mentioned above.
  2277   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2278     than before, because now they are set up once in a generic manner.
  2279   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2280     Look for the general versions in Ring_and_Field (and Power if they concern
  2281     exponentiation).
  2282 
  2283 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2284 
  2285 * Records:
  2286   - Record types are now by default printed with their type abbreviation
  2287     instead of the list of all field types. This can be configured via
  2288     the reference "print_record_type_abbr".
  2289   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2290     (not enabled by default).
  2291   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2292     EX x. x = sel r to True (not enabled by default).
  2293   - Tactic "record_split_simp_tac" to split and simplify records added.
  2294 
  2295 * 'specification' command added, allowing for definition by
  2296   specification.  There is also an 'ax_specification' command that
  2297   introduces the new constants axiomatically.
  2298 
  2299 * arith(_tac) is now able to generate counterexamples for reals as well.
  2300 
  2301 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2302 
  2303 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2304   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2305 
  2306 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2307   matrix theory to linear programming.
  2308 
  2309 * Unions and Intersections:
  2310   The latex output syntax of UN and INT has been changed
  2311   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2312   i.e. the index formulae has become a subscript.
  2313   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2314 
  2315 * Unions and Intersections over Intervals:
  2316   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2317   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2318   like in normal math, and corresponding versions for < and for intersection.
  2319 
  2320 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2321   lexicographic dictonary ordering has been added as "lexord".
  2322 
  2323 * ML: the legacy theory structures Int and List have been removed. They had
  2324   conflicted with ML Basis Library structures having the same names.
  2325 
  2326 * 'refute' command added to search for (finite) countermodels.  Only works
  2327   for a fragment of HOL.  The installation of an external SAT solver is
  2328   highly recommended.  See "HOL/Refute.thy" for details.
  2329 
  2330 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2331   formulae under an assignment of free variables to random values.
  2332   In contrast to 'refute', it can deal with inductive datatypes,
  2333   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2334   for examples.
  2335 
  2336 
  2337 *** HOLCF ***
  2338 
  2339 * Streams now come with concatenation and are part of the HOLCF image
  2340 
  2341 
  2342 
  2343 New in Isabelle2003 (May 2003)
  2344 ------------------------------
  2345 
  2346 *** General ***
  2347 
  2348 * Provers/simplifier:
  2349 
  2350   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2351     Assumptions are now subject to complete mutual simplification,
  2352     not just from left to right. The simplifier now preserves
  2353     the order of assumptions.
  2354 
  2355     Potential INCOMPATIBILITY:
  2356 
  2357     -- simp sometimes diverges where the old version did
  2358        not, e.g. invoking simp on the goal
  2359 
  2360         [| P (f x); y = x; f x = f y |] ==> Q
  2361 
  2362        now gives rise to the infinite reduction sequence
  2363 
  2364         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2365 
  2366        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2367        kind of problem.
  2368 
  2369     -- Tactics combining classical reasoner and simplification (such as auto)
  2370        are also affected by this change, because many of them rely on
  2371        simp. They may sometimes diverge as well or yield a different numbers
  2372        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2373        in case of problems. Sometimes subsequent calls to the classical
  2374        reasoner will fail because a preceeding call to the simplifier too
  2375        eagerly simplified the goal, e.g. deleted redundant premises.
  2376 
  2377   - The simplifier trace now shows the names of the applied rewrite rules
  2378 
  2379   - You can limit the number of recursive invocations of the simplifier
  2380     during conditional rewriting (where the simplifie tries to solve the
  2381     conditions before applying the rewrite rule):
  2382     ML "simp_depth_limit := n"
  2383     where n is an integer. Thus you can force termination where previously
  2384     the simplifier would diverge.
  2385 
  2386   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2387 
  2388   - No longer aborts on failed congruence proof.  Instead, the
  2389     congruence is ignored.
  2390 
  2391 * Pure: New generic framework for extracting programs from constructive
  2392   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2393   as HOL/Extraction for some case studies.
  2394 
  2395 * Pure: The main goal of the proof state is no longer shown by default, only
  2396 the subgoals. This behaviour is controlled by a new flag.
  2397    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2398 (ML: Proof.show_main_goal).
  2399 
  2400 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2401 rules whose conclusion matches subgoal 1:
  2402       PG menu: Isabelle/Isar -> Show me -> matching rules
  2403 The rules are ordered by how closely they match the subgoal.
  2404 In particular, rules that solve a subgoal outright are displayed first
  2405 (or rather last, the way they are printed).
  2406 (ML: ProofGeneral.print_intros())
  2407 
  2408 * Pure: New flag trace_unify_fail causes unification to print
  2409 diagnostic information (PG: in trace buffer) when it fails. This is
  2410 useful for figuring out why single step proofs like rule, erule or
  2411 assumption failed.
  2412 
  2413 * Pure: Locale specifications now produce predicate definitions
  2414 according to the body of text (covering assumptions modulo local
  2415 definitions); predicate "loc_axioms" covers newly introduced text,
  2416 while "loc" is cumulative wrt. all included locale expressions; the
  2417 latter view is presented only on export into the global theory
  2418 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2419 on the old view without predicates;
  2420 
  2421 * Pure: predefined locales "var" and "struct" are useful for sharing
  2422 parameters (as in CASL, for example); just specify something like
  2423 ``var x + var y + struct M'' as import;
  2424 
  2425 * Pure: improved thms_containing: proper indexing of facts instead of
  2426 raw theorems; check validity of results wrt. current name space;
  2427 include local facts of proof configuration (also covers active
  2428 locales), cover fixed variables in index; may use "_" in term
  2429 specification; an optional limit for the number of printed facts may
  2430 be given (the default is 40);
  2431 
  2432 * Pure: disallow duplicate fact bindings within new-style theory files
  2433 (batch-mode only);
  2434 
  2435 * Provers: improved induct method: assumptions introduced by case
  2436 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2437 the goal statement); "foo" still refers to all facts collectively;
  2438 
  2439 * Provers: the function blast.overloaded has been removed: all constants
  2440 are regarded as potentially overloaded, which improves robustness in exchange
  2441 for slight decrease in efficiency;
  2442 
  2443 * Provers/linorder: New generic prover for transitivity reasoning over
  2444 linear orders.  Note: this prover is not efficient!
  2445 
  2446 * Isar: preview of problems to finish 'show' now produce an error
  2447 rather than just a warning (in interactive mode);
  2448 
  2449 
  2450 *** HOL ***
  2451 
  2452 * arith(_tac)
  2453 
  2454  - Produces a counter example if it cannot prove a goal.
  2455    Note that the counter example may be spurious if the goal is not a formula
  2456    of quantifier-free linear arithmetic.
  2457    In ProofGeneral the counter example appears in the trace buffer.
  2458 
  2459  - Knows about div k and mod k where k is a numeral of type nat or int.
  2460 
  2461  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2462    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2463    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2464 
  2465 * simp's arithmetic capabilities have been enhanced a bit: it now
  2466 takes ~= in premises into account (by performing a case split);
  2467 
  2468 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2469 are distributed over a sum of terms;
  2470 
  2471 * New tactic "trans_tac" and method "trans" instantiate
  2472 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2473 "<=", "<" and "=").
  2474 
  2475 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2476 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2477 
  2478 * 'typedef' command has new option "open" to suppress the set
  2479 definition;
  2480 
  2481 * functions Min and Max on finite sets have been introduced (theory
  2482 Finite_Set);
  2483 
  2484 * attribute [symmetric] now works for relations as well; it turns
  2485 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2486 
  2487 * induct over a !!-quantified statement (say !!x1..xn):
  2488   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2489 
  2490 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2491 %x. None. Warning: empty_def now refers to the previously hidden definition
  2492 of the empty set.
  2493 
  2494 * Algebra: formalization of classical algebra.  Intended as base for
  2495 any algebraic development in Isabelle.  Currently covers group theory
  2496 (up to Sylow's theorem) and ring theory (Universal Property of
  2497 Univariate Polynomials).  Contributions welcome;
  2498 
  2499 * GroupTheory: deleted, since its material has been moved to Algebra;
  2500 
  2501 * Complex: new directory of the complex numbers with numeric constants,
  2502 nonstandard complex numbers, and some complex analysis, standard and
  2503 nonstandard (Jacques Fleuriot);
  2504 
  2505 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2506 
  2507 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2508 Fleuriot);
  2509 
  2510 * Real/HahnBanach: updated and adapted to locales;
  2511 
  2512 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2513 Gray and Kramer);
  2514 
  2515 * UNITY: added the Meier-Sanders theory of progress sets;
  2516 
  2517 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2518 as abstract algorithms, instantiated to the JVM;
  2519 
  2520 * Bali: Java source language formalization. Type system, operational
  2521 semantics, axiomatic semantics. Supported language features:
  2522 classes, interfaces, objects,virtual methods, static methods,
  2523 static/instance fields, arrays, access modifiers, definite
  2524 assignment, exceptions.
  2525 
  2526 
  2527 *** ZF ***
  2528 
  2529 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2530 universe, etc.);
  2531 
  2532 * Main ZF: virtually all theories converted to new-style format;
  2533 
  2534 
  2535 *** ML ***
  2536 
  2537 * Pure: Tactic.prove provides sane interface for internal proofs;
  2538 omits the infamous "standard" operation, so this is more appropriate
  2539 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2540 
  2541 * Pure: improved error reporting of simprocs;
  2542 
  2543 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2544 up simprocs;
  2545 
  2546 
  2547 *** Document preparation ***
  2548 
  2549 * uses \par instead of \\ for line breaks in theory text. This may
  2550 shift some page breaks in large documents. To get the old behaviour
  2551 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2552 
  2553 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2554 other packages
  2555 
  2556 * \<euro> now needs package babel/greek instead of marvosym (which
  2557 broke \Rightarrow)
  2558 
  2559 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2560 textcomp package)
  2561 
  2562 
  2563 
  2564 New in Isabelle2002 (March 2002)
  2565 --------------------------------
  2566 
  2567 *** Document preparation ***
  2568 
  2569 * greatly simplified document preparation setup, including more
  2570 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2571 instructive isatool mkdir; users should basically be able to get
  2572 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2573 users may run a separate document processing stage manually like this:
  2574 "isatool usedir -D output HOL Test && isatool document Test/output";
  2575 
  2576 * theory dependency graph may now be incorporated into documents;
  2577 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2578 with \includegraphics of LaTeX;
  2579 
  2580 * proper spacing of consecutive markup elements, especially text
  2581 blocks after section headings;
  2582 
  2583 * support bold style (for single symbols only), input syntax is like
  2584 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2585 
  2586 * \<bullet> is now output as bold \cdot by default, which looks much
  2587 better in printed text;
  2588 
  2589 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2590 note that these symbols are currently unavailable in Proof General /
  2591 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2592 
  2593 * isatool latex no longer depends on changed TEXINPUTS, instead
  2594 isatool document copies the Isabelle style files to the target
  2595 location;
  2596 
  2597 
  2598 *** Isar ***
  2599 
  2600 * Pure/Provers: improved proof by cases and induction;
  2601   - 'case' command admits impromptu naming of parameters (such as
  2602     "case (Suc n)");
  2603   - 'induct' method divinates rule instantiation from the inductive
  2604     claim; no longer requires excessive ?P bindings for proper
  2605     instantiation of cases;
  2606   - 'induct' method properly enumerates all possibilities of set/type
  2607     rules; as a consequence facts may be also passed through *type*
  2608     rules without further ado;
  2609   - 'induct' method now derives symbolic cases from the *rulified*
  2610     rule (before it used to rulify cases stemming from the internal
  2611     atomized version); this means that the context of a non-atomic
  2612     statement becomes is included in the hypothesis, avoiding the
  2613     slightly cumbersome show "PROP ?case" form;
  2614   - 'induct' may now use elim-style induction rules without chaining
  2615     facts, using ``missing'' premises from the goal state; this allows
  2616     rules stemming from inductive sets to be applied in unstructured
  2617     scripts, while still benefitting from proper handling of non-atomic
  2618     statements; NB: major inductive premises need to be put first, all
  2619     the rest of the goal is passed through the induction;
  2620   - 'induct' proper support for mutual induction involving non-atomic
  2621     rule statements (uses the new concept of simultaneous goals, see
  2622     below);
  2623   - append all possible rule selections, but only use the first
  2624     success (no backtracking);
  2625   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2626   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2627   - added 'print_induct_rules' (covered by help item in recent Proof
  2628     General versions);
  2629   - moved induct/cases attributes to Pure, methods to Provers;
  2630   - generic method setup instantiated for FOL and HOL;
  2631 
  2632 * Pure: support multiple simultaneous goal statements, for example
  2633 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2634 meta-level mechanism, this acts as if several individual goals had
  2635 been stated separately; in particular common proof methods need to be
  2636 repeated in order to cover all claims; note that a single elimination
  2637 step is *not* sufficient to establish the two conjunctions, so this
  2638 fails:
  2639 
  2640   assume "A & B" then have A and B ..   (*".." fails*)
  2641 
  2642 better use "obtain" in situations as above; alternative refer to
  2643 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2644 
  2645 * Pure: proper integration with ``locales''; unlike the original
  2646 version by Florian Kammller, Isar locales package high-level proof
  2647 contexts rather than raw logical ones (e.g. we admit to include
  2648 attributes everywhere); operations on locales include merge and
  2649 rename; support for implicit arguments (``structures''); simultaneous
  2650 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2651 some examples;
  2652 
  2653 * Pure: the following commands have been ``localized'', supporting a
  2654 target locale specification "(in name)": 'lemma', 'theorem',
  2655 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2656 stored both within the locale and at the theory level (exported and
  2657 qualified by the locale name);
  2658 
  2659 * Pure: theory goals may now be specified in ``long'' form, with
  2660 ad-hoc contexts consisting of arbitrary locale elements. for example
  2661 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2662 definitions may be given, too); the result is a meta-level rule with
  2663 the context elements being discharged in the obvious way;
  2664 
  2665 * Pure: new proof command 'using' allows to augment currently used
  2666 facts after a goal statement ('using' is syntactically analogous to
  2667 'apply', but acts on the goal's facts only); this allows chained facts
  2668 to be separated into parts given before and after a claim, as in
  2669 ``from a and b have C using d and e <proof>'';
  2670 
  2671 * Pure: renamed "antecedent" case to "rule_context";
  2672 
  2673 * Pure: new 'judgment' command records explicit information about the
  2674 object-logic embedding (used by several tools internally); no longer
  2675 use hard-wired "Trueprop";
  2676 
  2677 * Pure: added 'corollary' command;
  2678 
  2679 * Pure: fixed 'token_translation' command;
  2680 
  2681 * Pure: removed obsolete 'exported' attribute;
  2682 
  2683 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2684 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2685 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2686 
  2687 * Pure: method 'atomize' presents local goal premises as object-level
  2688 statements (atomic meta-level propositions); setup controlled via
  2689 rewrite rules declarations of 'atomize' attribute; example
  2690 application: 'induct' method with proper rule statements in improper
  2691 proof *scripts*;
  2692 
  2693 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2694 now consider the syntactic context of assumptions, giving a better
  2695 chance to get type-inference of the arguments right (this is
  2696 especially important for locales);
  2697 
  2698 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2699 mode;
  2700 
  2701 * Pure/obtain: the formal conclusion "thesis", being marked as
  2702 ``internal'', may no longer be reference directly in the text;
  2703 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2704 situations;
  2705 
  2706 * Pure: generic 'sym' attribute which declares a rule both as pure
  2707 'elim?' and for the 'symmetric' operation;
  2708 
  2709 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2710 text; the fixed correlation with particular command syntax has been
  2711 discontinued;
  2712 
  2713 * Pure: new method 'rules' is particularly well-suited for proof
  2714 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2715 but often produces more compact proof terms with less detours;
  2716 
  2717 * Pure/Provers/classical: simplified integration with pure rule
  2718 attributes and methods; the classical "intro?/elim?/dest?"
  2719 declarations coincide with the pure ones; the "rule" method no longer
  2720 includes classically swapped intros; "intro" and "elim" methods no
  2721 longer pick rules from the context; also got rid of ML declarations
  2722 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2723 INCOMPATIBILITY;
  2724 
  2725 * Provers/classical: attribute 'swapped' produces classical inversions
  2726 of introduction rules;
  2727 
  2728 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2729 rules instead of full simplifier context; 'iff' attribute handles
  2730 conditional rules;
  2731 
  2732 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2733 
  2734 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2735 "(permissive)" option to recover old behavior;
  2736 
  2737 * HOL: 'inductive' no longer features separate (collective) attributes
  2738 for 'intros' (was found too confusing);
  2739 
  2740 * HOL: properly declared induction rules less_induct and
  2741 wf_induct_rule;
  2742 
  2743 
  2744 *** HOL ***
  2745 
  2746 * HOL: moved over to sane numeral syntax; the new policy is as
  2747 follows:
  2748 
  2749   - 0 and 1 are polymorphic constants, which are defined on any
  2750   numeric type (nat, int, real etc.);
  2751 
  2752   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2753   binary representation internally;
  2754 
  2755   - type nat has special constructor Suc, and generally prefers Suc 0
  2756   over 1::nat and Suc (Suc 0) over 2::nat;
  2757 
  2758 This change may cause significant problems of INCOMPATIBILITY; here
  2759 are some hints on converting existing sources:
  2760 
  2761   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2762   entities, so expressions involving "-" (unary or binary minus) need
  2763   to be spaced properly;
  2764 
  2765   - existing occurrences of "1" may need to be constraint "1::nat" or
  2766   even replaced by Suc 0; similar for old "2";
  2767 
  2768   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2769 
  2770   - remove all special provisions on numerals in proofs;
  2771 
  2772 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2773 representation (depends on bin_arith_simps in the default context);
  2774 
  2775 * HOL: symbolic syntax for x^2 (numeral 2);
  2776 
  2777 * HOL: the class of all HOL types is now called "type" rather than
  2778 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2779 in axclass/classes, instance/arities, and (usually rare) occurrences
  2780 in typings (of consts etc.); internally the class is called
  2781 "HOL.type", ML programs should refer to HOLogic.typeS;
  2782 
  2783 * HOL/record package improvements:
  2784   - new derived operations "fields" to build a partial record section,
  2785     "extend" to promote a fixed record to a record scheme, and
  2786     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2787     declared as simp by default;
  2788   - shared operations ("more", "fields", etc.) now need to be always
  2789     qualified) --- potential INCOMPATIBILITY;
  2790   - removed "make_scheme" operations (use "make" with "extend") --
  2791     INCOMPATIBILITY;
  2792   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2793   - provides cases/induct rules for use with corresponding Isar
  2794     methods (for concrete records, record schemes, concrete more
  2795     parts, and schematic more parts -- in that order);
  2796   - internal definitions directly based on a light-weight abstract
  2797     theory of product types over typedef rather than datatype;
  2798 
  2799 * HOL: generic code generator for generating executable ML code from
  2800 specifications; specific support for HOL constructs such as inductive
  2801 datatypes and sets, as well as recursive functions; can be invoked
  2802 via 'generate_code' theory section;
  2803 
  2804 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2805 
  2806 * HOL: consolidated and renamed several theories.  In particular:
  2807         Ord.thy has been absorbed into HOL.thy
  2808         String.thy has been absorbed into List.thy
  2809 
  2810 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2811 (beware of argument permutation!);
  2812 
  2813 * HOL: linorder_less_split superseded by linorder_cases;
  2814 
  2815 * HOL/List: "nodups" renamed to "distinct";
  2816 
  2817 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2818 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2819   - Ex_def has changed, now need to use some_eq_ex
  2820 
  2821 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2822 in this (rare) case use:
  2823 
  2824   delSWrapper "split_all_tac"
  2825   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2826 
  2827 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2828 MAY FAIL;
  2829 
  2830 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2831 Isabelle's type classes, ^ on functions and relations has too general
  2832 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2833 necessary to attach explicit type constraints;
  2834 
  2835 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2836 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2837 renamed accordingly (eg "compI" -> "rel_compI").
  2838 
  2839 * HOL: syntax translations now work properly with numerals and records
  2840 expressions;
  2841 
  2842 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2843 of "lam" -- INCOMPATIBILITY;
  2844 
  2845 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2846 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2847 renamed "Product_Type.unit";
  2848 
  2849 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2850 
  2851 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2852 the "cases" method);
  2853 
  2854 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2855 Florian Kammller);
  2856 
  2857 * HOL/IMP: updated and converted to new-style theory format; several
  2858 parts turned into readable document, with proper Isar proof texts and
  2859 some explanations (by Gerwin Klein);
  2860 
  2861 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2862 
  2863 * HOL-Hyperreal is now a logic image;
  2864 
  2865 
  2866 *** HOLCF ***
  2867 
  2868 * Isar: consts/constdefs supports mixfix syntax for continuous
  2869 operations;
  2870 
  2871 * Isar: domain package adapted to new-style theory format, e.g. see
  2872 HOLCF/ex/Dnat.thy;
  2873 
  2874 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2875 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2876 lift.induct_tac, always use UU instead of Undef;
  2877 
  2878 * HOLCF/IMP: updated and converted to new-style theory;
  2879 
  2880 
  2881 *** ZF ***
  2882 
  2883 * Isar: proper integration of logic-specific tools and packages,
  2884 including theory commands '(co)inductive', '(co)datatype',
  2885 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2886 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2887 
  2888 * theory Main no longer includes AC; for the Axiom of Choice, base
  2889 your theory on Main_ZFC;
  2890 
  2891 * the integer library now covers quotients and remainders, with many
  2892 laws relating division to addition, multiplication, etc.;
  2893 
  2894 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2895 typeless version of the formalism;
  2896 
  2897 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2898 format;
  2899 
  2900 * ZF/Induct: new directory for examples of inductive definitions,
  2901 including theory Multiset for multiset orderings; converted to
  2902 new-style theory format;
  2903 
  2904 * ZF: many new theorems about lists, ordinals, etc.;
  2905 
  2906 
  2907 *** General ***
  2908 
  2909 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2910 variable proof controls level of detail: 0 = no proofs (only oracle
  2911 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2912 also ref manual for further ML interfaces;
  2913 
  2914 * Pure/axclass: removed obsolete ML interface
  2915 goal_subclass/goal_arity;
  2916 
  2917 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2918 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2919 separate tokens, so expressions involving minus need to be spaced
  2920 properly;
  2921 
  2922 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2923 rather than "infixl" or "infixr";
  2924 
  2925 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2926 sort constraint specifications in type inference; e.g. "x::_::foo"
  2927 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2928 type variable);
  2929 
  2930 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2931 control output of nested => (types); the default behavior is
  2932 "type_brackets";
  2933 
  2934 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2935 tokens into AST constants;
  2936 
  2937 * Pure/syntax: prefer later declarations of translations and print
  2938 translation functions; potential INCOMPATIBILITY: need to reverse
  2939 multiple declarations for same syntax element constant;
  2940 
  2941 * Pure/show_hyps reset by default (in accordance to existing Isar
  2942 practice);
  2943 
  2944 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2945 addSafter;
  2946 
  2947 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2948 as well;
  2949 
  2950 * system: tested support for MacOS X; should be able to get Isabelle +
  2951 Proof General to work in a plain Terminal after installing Poly/ML
  2952 (e.g. from the Isabelle distribution area) and GNU bash alone
  2953 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2954 support requires further installations, e.g. from
  2955 http://fink.sourceforge.net/);
  2956 
  2957 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2958 
  2959 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2960 of 40 MB), cf. ML_OPTIONS;
  2961 
  2962 * system: Proof General keywords specification is now part of the
  2963 Isabelle distribution (see etc/isar-keywords.el);
  2964 
  2965 * system: support for persistent Proof General sessions (refrain from
  2966 outdating all loaded theories on startup); user may create writable
  2967 logic images like this: ``isabelle -q HOL Test'';
  2968 
  2969 * system: smart selection of Isabelle process versus Isabelle
  2970 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2971 run both "isabelle" and "Isabelle" even if file names are badly
  2972 damaged (executable inspects the case of the first letter of its own
  2973 name); added separate "isabelle-process" and "isabelle-interface";
  2974 
  2975 * system: refrain from any attempt at filtering input streams; no
  2976 longer support ``8bit'' encoding of old isabelle font, instead proper
  2977 iso-latin characters may now be used; the related isatools
  2978 "symbolinput" and "nonascii" have disappeared as well;
  2979 
  2980 * system: removed old "xterm" interface (the print modes "xterm" and
  2981 "xterm_color" are still available for direct use in a suitable
  2982 terminal);
  2983 
  2984 
  2985 
  2986 New in Isabelle99-2 (February 2001)
  2987 -----------------------------------
  2988 
  2989 *** Overview of INCOMPATIBILITIES ***
  2990 
  2991 * HOL: please note that theories in the Library and elsewhere often use the
  2992 new-style (Isar) format; to refer to their theorems in an ML script you must
  2993 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2994 
  2995 * HOL: inductive package no longer splits induction rule aggressively,
  2996 but only as far as specified by the introductions given; the old
  2997 format may be recovered via ML function complete_split_rule or attribute
  2998 'split_rule (complete)';
  2999 
  3000 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3001 gfp_Tarski to gfp_unfold;
  3002 
  3003 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3004 
  3005 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3006 relation); infix "^^" has been renamed "``"; infix "``" has been
  3007 renamed "`"; "univalent" has been renamed "single_valued";
  3008 
  3009 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3010 operation;
  3011 
  3012 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3013 
  3014 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3015 
  3016 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3017 consequence, it is no longer monotonic wrt. the local goal context
  3018 (which is now passed through the inductive cases);
  3019 
  3020 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3021 \<gg> to \<ggreater>;
  3022 
  3023 
  3024 *** Document preparation ***
  3025 
  3026 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3027 available: are "it" for near math-mode best-style output, "sl" for
  3028 slanted text style, and "tt" for plain type-writer; if no
  3029 \isabellestyle command is given, output is according to slanted
  3030 type-writer);
  3031 
  3032 * support sub/super scripts (for single symbols only), input syntax is
  3033 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3034 
  3035 * some more standard symbols; see Appendix A of the system manual for
  3036 the complete list of symbols defined in isabellesym.sty;
  3037 
  3038 * improved isabelle style files; more abstract symbol implementation
  3039 (should now use \isamath{...} and \isatext{...} in custom symbol
  3040 definitions);
  3041 
  3042 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3043 state; Note that presentation of goal states does not conform to
  3044 actual human-readable proof documents.  Please do not include goal
  3045 states into document output unless you really know what you are doing!
  3046 
  3047 * proper indentation of antiquoted output with proportional LaTeX
  3048 fonts;
  3049 
  3050 * no_document ML operator temporarily disables LaTeX document
  3051 generation;
  3052 
  3053 * isatool unsymbolize tunes sources for plain ASCII communication;
  3054 
  3055 
  3056 *** Isar ***
  3057 
  3058 * Pure: Isar now suffers initial goal statements to contain unbound
  3059 schematic variables (this does not conform to actual readable proof
  3060 documents, due to unpredictable outcome and non-compositional proof
  3061 checking); users who know what they are doing may use schematic goals
  3062 for Prolog-style synthesis of proven results;
  3063 
  3064 * Pure: assumption method (an implicit finishing) now handles actual
  3065 rules as well;
  3066 
  3067 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3068 initial goal, declare "that" only as Pure intro (only for single
  3069 steps); the "that" rule assumption may now be involved in implicit
  3070 finishing, thus ".." becomes a feasible for trivial obtains;
  3071 
  3072 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3073 instance proofs may be performed by "..";
  3074 
  3075 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3076 statements as well;
  3077 
  3078 * Pure: more robust selection of calculational rules;
  3079 
  3080 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3081 rule (as well as the assumption rule);
  3082 
  3083 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3084 lemmas, using the graph browser tool;
  3085 
  3086 * Pure: predict failure of "show" in interactive mode;
  3087 
  3088 * Pure: 'thms_containing' now takes actual terms as arguments;
  3089 
  3090 * HOL: improved method 'induct' --- now handles non-atomic goals
  3091 (potential INCOMPATIBILITY); tuned error handling;
  3092 
  3093 * HOL: cases and induct rules now provide explicit hints about the
  3094 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3095 any remaining facts are inserted into the goal verbatim;
  3096 
  3097 * HOL: local contexts (aka cases) may now contain term bindings as
  3098 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3099 the result to be shown in each case;
  3100 
  3101 * HOL: added 'recdef_tc' command;
  3102 
  3103 * isatool convert assists in eliminating legacy ML scripts;
  3104 
  3105 
  3106 *** HOL ***
  3107 
  3108 * HOL/Library: a collection of generic theories to be used together
  3109 with main HOL; the theory loader path already includes this directory
  3110 by default; the following existing theories have been moved here:
  3111 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3112 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3113 
  3114 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3115 modelling and verification task performed in Isabelle/HOL +
  3116 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3117 
  3118 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3119 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3120 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3121 'domain', this makes the theory consistent with mathematical
  3122 literature;
  3123 
  3124 * HOL basics: added overloaded operations "inverse" and "divide"
  3125 (infix "/"), syntax for generic "abs" operation, generic summation
  3126 operator \<Sum>;
  3127 
  3128 * HOL/typedef: simplified package, provide more useful rules (see also
  3129 HOL/subset.thy);
  3130 
  3131 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3132 now expressed as a proper nested rule (old-style tactic scripts may
  3133 require atomize_strip_tac to cope with non-atomic premises);
  3134 
  3135 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3136 to "split_conv" (old name still available for compatibility);
  3137 
  3138 * HOL: improved concrete syntax for strings (e.g. allows translation
  3139 rules with string literals);
  3140 
  3141 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3142  and Fleuriot's mechanization of analysis, including the transcendental
  3143  functions for the reals;
  3144 
  3145 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3146 
  3147 
  3148 *** CTT ***
  3149 
  3150 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3151 "lam" is displayed as TWO lambda-symbols
  3152 
  3153 * CTT: theory Main now available, containing everything (that is, Bool
  3154 and Arith);
  3155 
  3156 
  3157 *** General ***
  3158 
  3159 * Pure: the Simplifier has been implemented properly as a derived rule
  3160 outside of the actual kernel (at last!); the overall performance
  3161 penalty in practical applications is about 50%, while reliability of
  3162 the Isabelle inference kernel has been greatly improved;
  3163 
  3164 * print modes "brackets" and "no_brackets" control output of nested =>
  3165 (types) and ==> (props); the default behaviour is "brackets";
  3166 
  3167 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3168 as assumptions as well;
  3169 
  3170 * system: support Poly/ML 4.0;
  3171 
  3172 * system: isatool install handles KDE version 1 or 2;
  3173 
  3174 
  3175 
  3176 New in Isabelle99-1 (October 2000)
  3177 ----------------------------------
  3178 
  3179 *** Overview of INCOMPATIBILITIES ***
  3180 
  3181 * HOL: simplification of natural numbers is much changed; to partly
  3182 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3183 issue the following ML commands:
  3184 
  3185   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3186   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3187 
  3188 * HOL: simplification no longer dives into case-expressions; this is
  3189 controlled by "t.weak_case_cong" for each datatype t;
  3190 
  3191 * HOL: nat_less_induct renamed to less_induct;
  3192 
  3193 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3194 fixsome to patch .thy and .ML sources automatically;
  3195 
  3196   select_equality  -> some_equality
  3197   select_eq_Ex     -> some_eq_ex
  3198   selectI2EX       -> someI2_ex
  3199   selectI2         -> someI2
  3200   selectI          -> someI
  3201   select1_equality -> some1_equality
  3202   Eps_sym_eq       -> some_sym_eq_trivial
  3203   Eps_eq           -> some_eq_trivial
  3204 
  3205 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3206 
  3207 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3208 instead);
  3209 
  3210 * HOL: the recursion equations generated by 'recdef' are now called
  3211 f.simps instead of f.rules;
  3212 
  3213 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3214 
  3215 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3216 sometimes be needed;
  3217 
  3218 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3219 
  3220 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3221 
  3222 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3223 product is now "<*>" instead of "Times"; the lexicographic product is
  3224 now "<*lex*>" instead of "**";
  3225 
  3226 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3227 of main HOL, but was unused); better use HOL's datatype package;
  3228 
  3229 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3230 the old syntax may be recovered as follows:
  3231 
  3232   syntax (symbols)
  3233     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3234       (infixl "\\<oplus>" 100)
  3235 
  3236 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3237 
  3238 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3239 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3240 internally;
  3241 
  3242 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3243 changed from A/r to A//r;
  3244 
  3245 * ZF: new treatment of arithmetic (nat & int) may break some old
  3246 proofs;
  3247 
  3248 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3249 rulify -> rule_format, elimify -> elim_format, ...);
  3250 
  3251 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3252 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3253 should have to change intro!! to intro? only); replaced "delrule" by
  3254 "rule del";
  3255 
  3256 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3257 
  3258 * Provers: strengthened force_tac by using new first_best_tac;
  3259 
  3260 * LaTeX document preparation: several changes of isabelle.sty (see
  3261 lib/texinputs);
  3262 
  3263 
  3264 *** Document preparation ***
  3265 
  3266 * formal comments (text blocks etc.) in new-style theories may now
  3267 contain antiquotations of thm/prop/term/typ/text to be presented
  3268 according to latex print mode; concrete syntax is like this:
  3269 @{term[show_types] "f(x) = a + x"};
  3270 
  3271 * isatool mkdir provides easy setup of Isabelle session directories,
  3272 including proper document sources;
  3273 
  3274 * generated LaTeX sources are now deleted after successful run
  3275 (isatool document -c); may retain a copy somewhere else via -D option
  3276 of isatool usedir;
  3277 
  3278 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3279 style files, achieving self-contained LaTeX sources and simplifying
  3280 LaTeX debugging;
  3281 
  3282 * old-style theories now produce (crude) LaTeX output as well;
  3283 
  3284 * browser info session directories are now self-contained (may be put
  3285 on WWW server seperately); improved graphs of nested sessions; removed
  3286 graph for 'all sessions';
  3287 
  3288 * several improvements in isabelle style files; \isabellestyle{it}
  3289 produces fake math mode output; \isamarkupheader is now \section by
  3290 default; see lib/texinputs/isabelle.sty etc.;
  3291 
  3292 
  3293 *** Isar ***
  3294 
  3295 * Isar/Pure: local results and corresponding term bindings are now
  3296 subject to Hindley-Milner polymorphism (similar to ML); this
  3297 accommodates incremental type-inference very nicely;
  3298 
  3299 * Isar/Pure: new derived language element 'obtain' supports
  3300 generalized existence reasoning;
  3301 
  3302 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3303 support accumulation of results, without applying any rules yet;
  3304 useful to collect intermediate results without explicit name
  3305 references, and for use with transitivity rules with more than 2
  3306 premises;
  3307 
  3308 * Isar/Pure: scalable support for case-analysis type proofs: new
  3309 'case' language element refers to local contexts symbolically, as
  3310 produced by certain proof methods; internally, case names are attached
  3311 to theorems as "tags";
  3312 
  3313 * Isar/Pure: theory command 'hide' removes declarations from
  3314 class/type/const name spaces;
  3315 
  3316 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3317 indicate potential overloading;
  3318 
  3319 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3320 
  3321 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3322 "{a,b,c}" instead of {a,b,c};
  3323 
  3324 * Isar/Pure now provides its own version of intro/elim/dest
  3325 attributes; useful for building new logics, but beware of confusion
  3326 with the version in Provers/classical;
  3327 
  3328 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3329 case name 'antecedent';
  3330 
  3331 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3332 to the current context is now done automatically);
  3333 
  3334 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3335 for definining proof methods in ML;
  3336 
  3337 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3338 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3339 most cases, one should have to change intro!! to intro? only);
  3340 replaced "delrule" by "rule del";
  3341 
  3342 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3343 'symmetric' attribute (the latter supercedes [RS sym]);
  3344 
  3345 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3346 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3347 well (including splits);
  3348 
  3349 * Isar/Provers: Simplifier and Classical methods now support all kind
  3350 of modifiers used in the past, including 'cong', 'iff', etc.
  3351 
  3352 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3353 of Simplifier and Classical reasoner);
  3354 
  3355 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3356 now support named cases; major packages (inductive, datatype, primrec,
  3357 recdef) support case names and properly name parameters;
  3358 
  3359 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3360 monotonicity conditions are extracted to be proven at end of
  3361 calculations;
  3362 
  3363 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3364 method anyway;
  3365 
  3366 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3367 split_if split_if_asm; datatype package provides theorems foo.splits =
  3368 foo.split foo.split_asm for each datatype;
  3369 
  3370 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3371 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3372 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3373 use "(cases (simplified))" method in proper proof texts);
  3374 
  3375 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3376 
  3377 * Isar: names of theorems etc. may be natural numbers as well;
  3378 
  3379 * Isar: 'pr' command: optional arguments for goals_limit and
  3380 ProofContext.prems_limit; no longer prints theory contexts, but only
  3381 proof states;
  3382 
  3383 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3384 additional print modes to be specified; e.g. "pr(latex)" will print
  3385 proof state according to the Isabelle LaTeX style;
  3386 
  3387 * Isar: improved support for emulating tactic scripts, including proof
  3388 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3389 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3390 (for HOL datatypes);
  3391 
  3392 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3393 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3394 'proof method scripts' have to be in depth-first order;
  3395 
  3396 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3397 
  3398 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3399 should instead use individual commands for printing items
  3400 (print_commands, print_methods etc.);
  3401 
  3402 * Isar: added 'nothing' --- the empty list of theorems;
  3403 
  3404 
  3405 *** HOL ***
  3406 
  3407 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3408 corresponding virtual machine and a specification of its bytecode
  3409 verifier and a lightweight bytecode verifier, including proofs of
  3410 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3411 Cornelia Pusch (see also the homepage of project Bali at
  3412 http://isabelle.in.tum.de/Bali/);
  3413 
  3414 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3415 Clemens Ballarin;
  3416 
  3417 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3418 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3419 Rasmussen;
  3420 
  3421 * HOL/Lattice: fundamental concepts of lattice theory and order
  3422 structures, including duals, properties of bounds versus algebraic
  3423 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3424 Theorem for complete lattices etc.; may also serve as a demonstration
  3425 for abstract algebraic reasoning using axiomatic type classes, and
  3426 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3427 
  3428 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3429 von Oheimb;
  3430 
  3431 * HOL/IMPP: extension of IMP with local variables and mutually
  3432 recursive procedures, by David von Oheimb;
  3433 
  3434 * HOL/Lambda: converted into new-style theory and document;
  3435 
  3436 * HOL/ex/Multiquote: example of multiple nested quotations and
  3437 anti-quotations -- basically a generalized version of de-Bruijn
  3438 representation; very useful in avoiding lifting of operations;
  3439 
  3440 * HOL/record: added general record equality rule to simpset; fixed
  3441 select-update simplification procedure to handle extended records as
  3442 well; admit "r" as field name;
  3443 
  3444 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3445 other numeric types and also as the identity of groups, rings, etc.;
  3446 
  3447 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3448 Types nat and int belong to this axclass;
  3449 
  3450 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3451    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3452    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3453   two terms #m*u and #n*u are replaced by #(m+n)*u
  3454     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3455   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3456     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3457 
  3458 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3459 powerful prover for predicate logic but knows nothing of clasets; see
  3460 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3461 
  3462 * HOL: new version of "case_tac" subsumes both boolean case split and
  3463 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3464 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3465 
  3466 * HOL: simplification no longer dives into case-expressions: only the
  3467 selector expression is simplified, but not the remaining arms; to
  3468 enable full simplification of case-expressions for datatype t, you may
  3469 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3470 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3471 
  3472 * HOL/recdef: the recursion equations generated by 'recdef' for
  3473 function 'f' are now called f.simps instead of f.rules; if all
  3474 termination conditions are proved automatically, these simplification
  3475 rules are added to the simpset, as in primrec; rules may be named
  3476 individually as well, resulting in a separate list of theorems for
  3477 each equation;
  3478 
  3479 * HOL/While is a new theory that provides a while-combinator. It
  3480 permits the definition of tail-recursive functions without the
  3481 provision of a termination measure. The latter is necessary once the
  3482 invariant proof rule for while is applied.
  3483 
  3484 * HOL: new (overloaded) notation for the set of elements below/above
  3485 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3486 
  3487 * HOL: theorems impI, allI, ballI bound as "strip";
  3488 
  3489 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3490 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3491 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3492 
  3493 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3494 
  3495 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3496 main HOL, but was unused);
  3497 
  3498 * HOL: fewer consts declared as global (e.g. have to refer to
  3499 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3500 
  3501 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3502 in case of overlap with user translations (e.g. judgements over
  3503 tuples); (note that the underlying logical represenation is still
  3504 bogus);
  3505 
  3506 
  3507 *** ZF ***
  3508 
  3509 * ZF: simplification automatically cancels common terms in arithmetic
  3510 expressions over nat and int;
  3511 
  3512 * ZF: new treatment of nat to minimize type-checking: all operators
  3513 coerce their operands to a natural number using the function natify,
  3514 making the algebraic laws unconditional;
  3515 
  3516 * ZF: as above, for int: operators coerce their operands to an integer
  3517 using the function intify;
  3518 
  3519 * ZF: the integer library now contains many of the usual laws for the
  3520 orderings, including $<=, and monotonicity laws for $+ and $*;
  3521 
  3522 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3523 simplification;
  3524 
  3525 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3526 to the simplifier and classical reasoner simultaneously;
  3527 
  3528 
  3529 *** General ***
  3530 
  3531 * Provers: blast_tac now handles actual object-logic rules as
  3532 assumptions; note that auto_tac uses blast_tac internally as well;
  3533 
  3534 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3535 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3536 
  3537 * Provers: delrules now handles destruct rules as well (no longer need
  3538 explicit make_elim);
  3539 
  3540 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3541   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3542 use instead the strong form,
  3543   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3544 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3545 from destruct-rules;
  3546 
  3547 * Provers: Simplifier.easy_setup provides a fast path to basic
  3548 Simplifier setup for new object-logics;
  3549 
  3550 * Pure: AST translation rules no longer require constant head on LHS;
  3551 
  3552 * Pure: improved name spaces: ambiguous output is qualified; support
  3553 for hiding of names;
  3554 
  3555 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3556 XSYMBOL_HOME; no longer need to do manual configuration in most
  3557 situations;
  3558 
  3559 * system: compression of ML heaps images may now be controlled via -c
  3560 option of isabelle and isatool usedir (currently only observed by
  3561 Poly/ML);
  3562 
  3563 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3564 useful for remote X11);
  3565 
  3566 * system: provide TAGS file for Isabelle sources;
  3567 
  3568 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3569 order;
  3570 
  3571 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3572 timing flag supersedes proof_timing and Toplevel.trace;
  3573 
  3574 * ML: new combinators |>> and |>>> for incremental transformations
  3575 with secondary results (e.g. certain theory extensions):
  3576 
  3577 * ML: PureThy.add_defs gets additional argument to indicate potential
  3578 overloading (usually false);
  3579 
  3580 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3581 results;
  3582 
  3583 
  3584 
  3585 New in Isabelle99 (October 1999)
  3586 --------------------------------
  3587 
  3588 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3589 
  3590 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3591 are no longer simplified.  (This allows the simplifier to unfold recursive
  3592 functional programs.)  To restore the old behaviour, declare
  3593 
  3594     Delcongs [if_weak_cong];
  3595 
  3596 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3597 complement;
  3598 
  3599 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3600 
  3601 * HOL/datatype: mutual_induct_tac no longer exists --
  3602   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3603 
  3604 * HOL/typedef: fixed type inference for representing set; type
  3605 arguments now have to occur explicitly on the rhs as type constraints;
  3606 
  3607 * ZF: The con_defs part of an inductive definition may no longer refer
  3608 to constants declared in the same theory;
  3609 
  3610 * HOL, ZF: the function mk_cases, generated by the inductive
  3611 definition package, has lost an argument.  To simplify its result, it
  3612 uses the default simpset instead of a supplied list of theorems.
  3613 
  3614 * HOL/List: the constructors of type list are now Nil and Cons;
  3615 
  3616 * Simplifier: the type of the infix ML functions
  3617         setSSolver addSSolver setSolver addSolver
  3618 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3619 for packaging solvers. A solver is created via
  3620         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3621 where the string argument is only a comment.
  3622 
  3623 
  3624 *** Proof tools ***
  3625 
  3626 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3627 decision procedure for linear arithmetic. Currently it is used for
  3628 types `nat', `int', and `real' in HOL (see below); it can, should and
  3629 will be instantiated for other types and logics as well.
  3630 
  3631 * The simplifier now accepts rewrite rules with flexible heads, eg
  3632      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3633   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3634   matching.
  3635 
  3636 
  3637 *** General ***
  3638 
  3639 * New Isabelle/Isar subsystem provides an alternative to traditional
  3640 tactical theorem proving; together with the ProofGeneral/isar user
  3641 interface it offers an interactive environment for developing human
  3642 readable proof documents (Isar == Intelligible semi-automated
  3643 reasoning); for further information see isatool doc isar-ref,
  3644 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3645 
  3646 * improved and simplified presentation of theories: better HTML markup
  3647 (including colors), graph views in several sizes; isatool usedir now
  3648 provides a proper interface for user theories (via -P option); actual
  3649 document preparation based on (PDF)LaTeX is available as well (for
  3650 new-style theories only); see isatool doc system for more information;
  3651 
  3652 * native support for Proof General, both for classic Isabelle and
  3653 Isabelle/Isar;
  3654 
  3655 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3656 using the graph browser tool;
  3657 
  3658 * Isabelle manuals now also available as PDF;
  3659 
  3660 * theory loader rewritten from scratch (may not be fully
  3661 bug-compatible); old loadpath variable has been replaced by show_path,
  3662 add_path, del_path, reset_path functions; new operations such as
  3663 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3664 isatool doc ref);
  3665 
  3666 * improved isatool install: option -k creates KDE application icon,
  3667 option -p DIR installs standalone binaries;
  3668 
  3669 * added ML_PLATFORM setting (useful for cross-platform installations);
  3670 more robust handling of platform specific ML images for SML/NJ;
  3671 
  3672 * the settings environment is now statically scoped, i.e. it is never
  3673 created again in sub-processes invoked from isabelle, isatool, or
  3674 Isabelle;
  3675 
  3676 * path element specification '~~' refers to '$ISABELLE_HOME';
  3677 
  3678 * in locales, the "assumes" and "defines" parts may be omitted if
  3679 empty;
  3680 
  3681 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3682 long arrows);
  3683 
  3684 * new print_mode "HTML";
  3685 
  3686 * new flag show_tags controls display of tags of theorems (which are
  3687 basically just comments that may be attached by some tools);
  3688 
  3689 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3690 mode and goal output format:
  3691 
  3692 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3693 244c244
  3694 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3695 ---
  3696 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3697 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3698 181c181
  3699 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3700 ---
  3701 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3702 
  3703 * function bind_thms stores lists of theorems (cf. bind_thm);
  3704 
  3705 * new shorthand tactics ftac, eatac, datac, fatac;
  3706 
  3707 * qed (and friends) now accept "" as result name; in that case the
  3708 theorem is not stored, but proper checks and presentation of the
  3709 result still apply;
  3710 
  3711 * theorem database now also indexes constants "Trueprop", "all",
  3712 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3713 
  3714 
  3715 *** HOL ***
  3716 
  3717 ** HOL arithmetic **
  3718 
  3719 * There are now decision procedures for linear arithmetic over nat and
  3720 int:
  3721 
  3722 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3723 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3724 are treated as atomic; subformulae not involving type `nat' or `int'
  3725 are ignored; quantified subformulae are ignored unless they are
  3726 positive universal or negative existential. The tactic has to be
  3727 invoked by hand and can be a little bit slow. In particular, the
  3728 running time is exponential in the number of occurrences of `min' and
  3729 `max', and `-' on `nat'.
  3730 
  3731 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3732 (negated) (in)equalities among the premises and the conclusion into
  3733 account (i.e. no compound formulae) and does not know about `min' and
  3734 `max', and `-' on `nat'. It is fast and is used automatically by the
  3735 simplifier.
  3736 
  3737 NB: At the moment, these decision procedures do not cope with mixed
  3738 nat/int formulae where the two parts interact, such as `m < n ==>
  3739 int(m) < int(n)'.
  3740 
  3741 * HOL/Numeral provides a generic theory of numerals (encoded
  3742 efficiently as bit strings); setup for types nat/int/real is in place;
  3743 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3744 int, existing theories and proof scripts may require a few additional
  3745 type constraints;
  3746 
  3747 * integer division and remainder can now be performed on constant
  3748 arguments;
  3749 
  3750 * many properties of integer multiplication, division and remainder
  3751 are now available;
  3752 
  3753 * An interface to the Stanford Validity Checker (SVC) is available through the
  3754 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3755 are proved automatically.  SVC must be installed separately, and its results
  3756 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3757 invocation of the underlying oracle).  For SVC see
  3758   http://verify.stanford.edu/SVC
  3759 
  3760 * IsaMakefile: the HOL-Real target now builds an actual image;
  3761 
  3762 
  3763 ** HOL misc **
  3764 
  3765 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3766 (in Isabelle/Isar) -- by Gertrud Bauer;
  3767 
  3768 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3769 analysis for assembly languages with subtypes;
  3770 
  3771 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3772 -- avoids syntactic ambiguities and treats state, transition, and
  3773 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3774 changed syntax and (many) tactics;
  3775 
  3776 * HOL/inductive: Now also handles more general introduction rules such
  3777   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3778   theorems are now maintained within the theory (maintained via the
  3779   "mono" attribute);
  3780 
  3781 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3782   (using function types) such as
  3783 
  3784   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3785 
  3786 * HOL/record: record_simproc (part of the default simpset) takes care
  3787 of selectors applied to updated records; record_split_tac is no longer
  3788 part of the default claset; update_defs may now be removed from the
  3789 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3790 
  3791   claset_ref () := claset() addSWrapper record_split_wrapper;
  3792   Delsimprocs [record_simproc]
  3793 
  3794 * HOL/typedef: fixed type inference for representing set; type
  3795 arguments now have to occur explicitly on the rhs as type constraints;
  3796 
  3797 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3798 names rather than an ML expression;
  3799 
  3800 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3801 supplied later.  Program schemes can be defined, such as
  3802     "While B C s = (if B s then While B C (C s) else s)"
  3803 where the well-founded relation can be chosen after B and C have been given.
  3804 
  3805 * HOL/List: the constructors of type list are now Nil and Cons;
  3806 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3807 course, ML tools referring to List.list.op # etc. have to be adapted;
  3808 
  3809 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3810 disabled by default; run isabelle with option -m HOL to get back to
  3811 the original Gordon/HOL-style output;
  3812 
  3813 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3814 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3815 
  3816 * HOL basic syntax simplified (more orthogonal): all variants of
  3817 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3818 Eps operator is provided as well: "SOME x. P[x]";
  3819 
  3820 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3821 
  3822 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3823 thus available for user theories;
  3824 
  3825 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3826 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3827 time;
  3828 
  3829 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3830 several times and then mp;
  3831 
  3832 
  3833 *** LK ***
  3834 
  3835 * the notation <<...>> is now available as a notation for sequences of
  3836 formulas;
  3837 
  3838 * the simplifier is now installed
  3839 
  3840 * the axiom system has been generalized (thanks to Soren Heilmann)
  3841 
  3842 * the classical reasoner now has a default rule database
  3843 
  3844 
  3845 *** ZF ***
  3846 
  3847 * new primrec section allows primitive recursive functions to be given
  3848 directly (as in HOL) over datatypes and the natural numbers;
  3849 
  3850 * new tactics induct_tac and exhaust_tac for induction (or case
  3851 analysis) over datatypes and the natural numbers;
  3852 
  3853 * the datatype declaration of type T now defines the recursor T_rec;
  3854 
  3855 * simplification automatically does freeness reasoning for datatype
  3856 constructors;
  3857 
  3858 * automatic type-inference, with AddTCs command to insert new
  3859 type-checking rules;
  3860 
  3861 * datatype introduction rules are now added as Safe Introduction rules
  3862 to the claset;
  3863 
  3864 * the syntax "if P then x else y" is now available in addition to
  3865 if(P,x,y);
  3866 
  3867 
  3868 *** Internal programming interfaces ***
  3869 
  3870 * tuned simplifier trace output; new flag debug_simp;
  3871 
  3872 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3873 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3874 
  3875 * AxClass.axclass_tac lost the theory argument;
  3876 
  3877 * tuned current_goals_markers semantics: begin / end goal avoids
  3878 printing empty lines;
  3879 
  3880 * removed prs and prs_fn hook, which was broken because it did not
  3881 include \n in its semantics, forcing writeln to add one
  3882 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3883 string -> unit if you really want to output text without newline;
  3884 
  3885 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3886 plain output, interface builders may have to enable 'isabelle_font'
  3887 mode to get Isabelle font glyphs as before;
  3888 
  3889 * refined token_translation interface; INCOMPATIBILITY: output length
  3890 now of type real instead of int;
  3891 
  3892 * theory loader actions may be traced via new ThyInfo.add_hook
  3893 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3894 your own database of information attached to *whole* theories -- as
  3895 opposed to intra-theory data slots offered via TheoryDataFun;
  3896 
  3897 * proper handling of dangling sort hypotheses (at last!);
  3898 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3899 extra sort hypotheses that can be witnessed from the type signature;
  3900 the force_strip_shyps flag is gone, any remaining shyps are simply
  3901 left in the theorem (with a warning issued by strip_shyps_warning);
  3902 
  3903 
  3904 
  3905 New in Isabelle98-1 (October 1998)
  3906 ----------------------------------
  3907 
  3908 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3909 
  3910 * several changes of automated proof tools;
  3911 
  3912 * HOL: major changes to the inductive and datatype packages, including
  3913 some minor incompatibilities of theory syntax;
  3914 
  3915 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3916 called `inj_on';
  3917 
  3918 * HOL: removed duplicate thms in Arith:
  3919   less_imp_add_less  should be replaced by  trans_less_add1
  3920   le_imp_add_le      should be replaced by  trans_le_add1
  3921 
  3922 * HOL: unary minus is now overloaded (new type constraints may be
  3923 required);
  3924 
  3925 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3926 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3927 now taken as an integer constant.
  3928 
  3929 * Pure: ML function 'theory_of' renamed to 'theory';
  3930 
  3931 
  3932 *** Proof tools ***
  3933 
  3934 * Simplifier:
  3935   1. Asm_full_simp_tac is now more aggressive.
  3936      1. It will sometimes reorient premises if that increases their power to
  3937         simplify.
  3938      2. It does no longer proceed strictly from left to right but may also
  3939         rotate premises to achieve further simplification.
  3940      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3941      old Asm_full_simp_tac in that it does not rotate premises.
  3942   2. The simplifier now knows a little bit about nat-arithmetic.
  3943 
  3944 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3945 allows for selected deletion of wrappers, by introduction of names for
  3946 wrapper functionals.  This implies that addbefore, addSbefore,
  3947 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3948 and that adding two tactics with the same name overwrites the first
  3949 one (emitting a warning).
  3950   type wrapper = (int -> tactic) -> (int -> tactic)
  3951   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3952   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3953   delWrapper, delSWrapper: claset *  string            -> claset
  3954   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3955 
  3956 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3957 semantics; addbefore now affects only the unsafe part of step_tac
  3958 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3959 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3960 by Force_tac;
  3961 
  3962 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3963 compWrapper; added safe wrapper (and access functions for it);
  3964 
  3965 * HOL/split_all_tac is now much faster and fails if there is nothing
  3966 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3967 and the names of the automatically generated variables have changed.
  3968 split_all_tac has moved within claset() from unsafe wrappers to safe
  3969 wrappers, which means that !!-bound variables are split much more
  3970 aggressively, and safe_tac and clarify_tac now split such variables.
  3971 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3972 Note: the same holds for record_split_tac, which does the job of
  3973 split_all_tac for record fields.
  3974 
  3975 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3976 permanently to the default simpset using Addsplits just like
  3977 Addsimps. They can be removed via Delsplits just like
  3978 Delsimps. Lower-case versions are also available.
  3979 
  3980 * HOL/Simplifier: The rule split_if is now part of the default
  3981 simpset. This means that the simplifier will eliminate all occurrences
  3982 of if-then-else in the conclusion of a goal. To prevent this, you can
  3983 either remove split_if completely from the default simpset by
  3984 `Delsplits [split_if]' or remove it in a specific call of the
  3985 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3986 other case splitting rules to/from the default simpset: every datatype
  3987 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3988 t is the name of the datatype).
  3989 
  3990 * Classical reasoner / Simplifier combination: new force_tac (and
  3991 derivatives Force_tac, force) combines rewriting and classical
  3992 reasoning (and whatever other tools) similarly to auto_tac, but is
  3993 aimed to solve the given subgoal completely.
  3994 
  3995 
  3996 *** General ***
  3997 
  3998 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3999 and `goalw': the theory is no longer needed as an explicit argument -
  4000 the current theory context is used; assumptions are no longer returned
  4001 at the ML-level unless one of them starts with ==> or !!; it is
  4002 recommended to convert to these new commands using isatool fixgoal
  4003 (backup your sources first!);
  4004 
  4005 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4006 the current theory context, and 'theory' to lookup stored theories;
  4007 
  4008 * new theory section 'locale' for declaring constants, assumptions and
  4009 definitions that have local scope;
  4010 
  4011 * new theory section 'nonterminals' for purely syntactic types;
  4012 
  4013 * new theory section 'setup' for generic ML setup functions
  4014 (e.g. package initialization);
  4015 
  4016 * the distribution now includes Isabelle icons: see
  4017 lib/logo/isabelle-{small,tiny}.xpm;
  4018 
  4019 * isatool install - install binaries with absolute references to
  4020 ISABELLE_HOME/bin;
  4021 
  4022 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4023 
  4024 * print mode 'emacs' reserved for Isamode;
  4025 
  4026 * support multiple print (ast) translations per constant name;
  4027 
  4028 * theorems involving oracles are now printed with a suffixed [!];
  4029 
  4030 
  4031 *** HOL ***
  4032 
  4033 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4034 
  4035 * HOL/inductive package reorganized and improved: now supports mutual
  4036 definitions such as
  4037 
  4038   inductive EVEN ODD
  4039     intrs
  4040       null "0 : EVEN"
  4041       oddI "n : EVEN ==> Suc n : ODD"
  4042       evenI "n : ODD ==> Suc n : EVEN"
  4043 
  4044 new theorem list "elims" contains an elimination rule for each of the
  4045 recursive sets; inductive definitions now handle disjunctive premises
  4046 correctly (also ZF);
  4047 
  4048 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4049 "mutual_induct" no longer exists - the induction rule is always
  4050 contained in "induct";
  4051 
  4052 
  4053 * HOL/datatype package re-implemented and greatly improved: now
  4054 supports mutually recursive datatypes such as
  4055 
  4056   datatype
  4057     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4058             | SUM ('a aexp) ('a aexp)
  4059             | DIFF ('a aexp) ('a aexp)
  4060             | NUM 'a
  4061   and
  4062     'a bexp = LESS ('a aexp) ('a aexp)
  4063             | AND ('a bexp) ('a bexp)
  4064             | OR ('a bexp) ('a bexp)
  4065 
  4066 as well as indirectly recursive datatypes such as
  4067 
  4068   datatype
  4069     ('a, 'b) term = Var 'a
  4070                   | App 'b ((('a, 'b) term) list)
  4071 
  4072 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4073 induction on mutually / indirectly recursive datatypes.
  4074 
  4075 Primrec equations are now stored in theory and can be accessed via
  4076 <function_name>.simps.
  4077 
  4078 INCOMPATIBILITIES:
  4079 
  4080   - Theories using datatypes must now have theory Datatype as an
  4081     ancestor.
  4082   - The specific <typename>.induct_tac no longer exists - use the
  4083     generic induct_tac instead.
  4084   - natE has been renamed to nat.exhaust - use exhaust_tac
  4085     instead of res_inst_tac ... natE. Note that the variable
  4086     names in nat.exhaust differ from the names in natE, this
  4087     may cause some "fragile" proofs to fail.
  4088   - The theorems split_<typename>_case and split_<typename>_case_asm
  4089     have been renamed to <typename>.split and <typename>.split_asm.
  4090   - Since default sorts of type variables are now handled correctly,
  4091     some datatype definitions may have to be annotated with explicit
  4092     sort constraints.
  4093   - Primrec definitions no longer require function name and type
  4094     of recursive argument.
  4095 
  4096 Consider using isatool fixdatatype to adapt your theories and proof
  4097 scripts to the new package (backup your sources first!).
  4098 
  4099 
  4100 * HOL/record package: considerably improved implementation; now
  4101 includes concrete syntax for record types, terms, updates; theorems
  4102 for surjective pairing and splitting !!-bound record variables; proof
  4103 support is as follows:
  4104 
  4105   1) standard conversions (selectors or updates applied to record
  4106 constructor terms) are part of the standard simpset;
  4107 
  4108   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4109 made part of standard simpset and claset via addIffs;
  4110 
  4111   3) a tactic for record field splitting (record_split_tac) is part of
  4112 the standard claset (addSWrapper);
  4113 
  4114 To get a better idea about these rules you may retrieve them via
  4115 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4116 the name of your record type.
  4117 
  4118 The split tactic 3) conceptually simplifies by the following rule:
  4119 
  4120   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4121 
  4122 Thus any record variable that is bound by meta-all will automatically
  4123 blow up into some record constructor term, consequently the
  4124 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4125 solve record problems automatically.
  4126 
  4127 
  4128 * reorganized the main HOL image: HOL/Integ and String loaded by
  4129 default; theory Main includes everything;
  4130 
  4131 * automatic simplification of integer sums and comparisons, using cancellation;
  4132 
  4133 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4134 
  4135 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4136 
  4137 * many new identities for unions, intersections, set difference, etc.;
  4138 
  4139 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4140 called split_if, split_split, split_sum_case and split_nat_case (to go
  4141 with add/delsplits);
  4142 
  4143 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4144 (?x::unit) = (); this is made part of the default simpset, which COULD
  4145 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4146 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4147 unit_abs_eta_conv is added in order to counter the effect of
  4148 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4149 %u.f();
  4150 
  4151 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4152 makes more sense);
  4153 
  4154 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4155   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4156   disjointness reasoning but breaking a few old proofs.
  4157 
  4158 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4159 to 'converse' from 'inverse' (for compatibility with ZF and some
  4160 literature);
  4161 
  4162 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4163 the well-founded relation;
  4164 
  4165 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4166     Compl A.  The "Compl" syntax remains available as input syntax for this
  4167     release ONLY.
  4168 
  4169 * HOL/Update: new theory of function updates:
  4170     f(a:=b) == %x. if x=a then b else f x
  4171 may also be iterated as in f(a:=b,c:=d,...);
  4172 
  4173 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4174 
  4175 * HOL/List:
  4176   - new function list_update written xs[i:=v] that updates the i-th
  4177     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4178   - new function `upt' written [i..j(] which generates the list
  4179     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4180     bound write [i..j], which is a shorthand for [i..j+1(].
  4181   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4182 
  4183 * HOL/Arith:
  4184   - removed 'pred' (predecessor) function;
  4185   - generalized some theorems about n-1;
  4186   - many new laws about "div" and "mod";
  4187   - new laws about greatest common divisors (see theory ex/Primes);
  4188 
  4189 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4190 instead of "inverse";
  4191 
  4192 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4193   of the multiset ordering;
  4194 
  4195 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4196   (not included by default);
  4197 
  4198 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4199 
  4200 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4201   programs, i.e. different program variables may have different types.
  4202 
  4203 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4204   [previously, this check worked only if the rewrite rule was unconditional]
  4205   Now rew can involve either definitions or equalities (either == or =).
  4206 
  4207 
  4208 *** ZF ***
  4209 
  4210 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4211   only the theorems proved on ZF.ML;
  4212 
  4213 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4214   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4215   disjointness reasoning but breaking a few old proofs.
  4216 
  4217 * ZF/Update: new theory of function updates
  4218     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4219   may also be iterated as in f(a:=b,c:=d,...);
  4220 
  4221 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4222 
  4223 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4224   [previously, this check worked only if the rewrite rule was unconditional]
  4225   Now rew can involve either definitions or equalities (either == or =).
  4226 
  4227 * case_tac provided for compatibility with HOL
  4228     (like the old excluded_middle_tac, but with subgoals swapped)
  4229 
  4230 
  4231 *** Internal programming interfaces ***
  4232 
  4233 * Pure: several new basic modules made available for general use, see
  4234 also src/Pure/README;
  4235 
  4236 * improved the theory data mechanism to support encapsulation (data
  4237 kind name replaced by private Object.kind, acting as authorization
  4238 key); new type-safe user interface via functor TheoryDataFun; generic
  4239 print_data function becomes basically useless;
  4240 
  4241 * removed global_names compatibility flag -- all theory declarations
  4242 are qualified by default;
  4243 
  4244 * module Pure/Syntax now offers quote / antiquote translation
  4245 functions (useful for Hoare logic etc. with implicit dependencies);
  4246 see HOL/ex/Antiquote for an example use;
  4247 
  4248 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4249 cterm -> thm;
  4250 
  4251 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4252 subgoal;
  4253 
  4254 * Display.print_goals function moved to Locale.print_goals;
  4255 
  4256 * standard print function for goals supports current_goals_markers
  4257 variable for marking begin of proof, end of proof, start of goal; the
  4258 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4259 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4260 for example;
  4261 
  4262 
  4263 
  4264 New in Isabelle98 (January 1998)
  4265 --------------------------------
  4266 
  4267 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4268 
  4269 * changed lexical syntax of terms / types: dots made part of long
  4270 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4271 
  4272 * simpset (and claset) reference variable replaced by functions
  4273 simpset / simpset_ref;
  4274 
  4275 * no longer supports theory aliases (via merge) and non-trivial
  4276 implicit merge of thms' signatures;
  4277 
  4278 * most internal names of constants changed due to qualified names;
  4279 
  4280 * changed Pure/Sequence interface (see Pure/seq.ML);
  4281 
  4282 
  4283 *** General Changes ***
  4284 
  4285 * hierachically structured name spaces (for consts, types, axms, thms
  4286 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4287 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4288 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4289 long_names for fully qualified output names; NOTE: ML programs
  4290 (special tactics, packages etc.) referring to internal names may have
  4291 to be adapted to cope with fully qualified names; in case of severe
  4292 backward campatibility problems try setting 'global_names' at compile
  4293 time to have enrything declared within a flat name space; one may also
  4294 fine tune name declarations in theories via the 'global' and 'local'
  4295 section;
  4296 
  4297 * reimplemented the implicit simpset and claset using the new anytype
  4298 data filed in signatures; references simpset:simpset ref etc. are
  4299 replaced by functions simpset:unit->simpset and
  4300 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4301 to patch your ML files accordingly;
  4302 
  4303 * HTML output now includes theory graph data for display with Java
  4304 applet or isatool browser; data generated automatically via isatool
  4305 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4306 
  4307 * defs may now be conditional; improved rewrite_goals_tac to handle
  4308 conditional equations;
  4309 
  4310 * defs now admits additional type arguments, using TYPE('a) syntax;
  4311 
  4312 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4313 creates a new theory node; implicit merge of thms' signatures is
  4314 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4315 transfer:theory->thm->thm in (rare) cases;
  4316 
  4317 * improved handling of draft signatures / theories; draft thms (and
  4318 ctyps, cterms) are automatically promoted to real ones;
  4319 
  4320 * slightly changed interfaces for oracles: admit many per theory, named
  4321 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4322 
  4323 * print_goals: optional output of const types (set show_consts and
  4324 show_types);
  4325 
  4326 * improved output of warnings (###) and errors (***);
  4327 
  4328 * subgoal_tac displays a warning if the new subgoal has type variables;
  4329 
  4330 * removed old README and Makefiles;
  4331 
  4332 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4333 
  4334 * removed obsolete init_pps and init_database;
  4335 
  4336 * deleted the obsolete tactical STATE, which was declared by
  4337     fun STATE tacfun st = tacfun st st;
  4338 
  4339 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4340 (which abbreviates $HOME);
  4341 
  4342 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4343 use isatool fixseq to adapt your ML programs (this works for fully
  4344 qualified references to the Sequence structure only!);
  4345 
  4346 * use_thy no longer requires writable current directory; it always
  4347 reloads .ML *and* .thy file, if either one is out of date;
  4348 
  4349 
  4350 *** Classical Reasoner ***
  4351 
  4352 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4353 tactics that use classical reasoning to simplify a subgoal without
  4354 splitting it into several subgoals;
  4355 
  4356 * Safe_tac: like safe_tac but uses the default claset;
  4357 
  4358 
  4359 *** Simplifier ***
  4360 
  4361 * added simplification meta rules:
  4362     (asm_)(full_)simplify: simpset -> thm -> thm;
  4363 
  4364 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4365 logics (again);
  4366 
  4367 * added prems argument to simplification procedures;
  4368 
  4369 * HOL, FOL, ZF: added infix function `addsplits':
  4370   instead of `<simpset> setloop (split_tac <thms>)'
  4371   you can simply write `<simpset> addsplits <thms>'
  4372 
  4373 
  4374 *** Syntax ***
  4375 
  4376 * TYPE('a) syntax for type reflection terms;
  4377 
  4378 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4379 
  4380 * pretty printer: changed order of mixfix annotation preference (again!);
  4381 
  4382 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4383 
  4384 
  4385 *** HOL ***
  4386 
  4387 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4388   with `addloop' of the simplifier to faciliate case splitting in premises.
  4389 
  4390 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4391 
  4392 * HOL/Auth: new protocol proofs including some for the Internet
  4393   protocol TLS;
  4394 
  4395 * HOL/Map: new theory of `maps' a la VDM;
  4396 
  4397 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4398 cancelling out common nat summands from =, <, <= (in)equalities, or
  4399 differences; simplification procedures nat_cancel_factor for
  4400 cancelling common factor from =, <, <= (in)equalities over natural
  4401 sums; nat_cancel contains both kinds of procedures, it is installed by
  4402 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4403 
  4404 * HOL/simplifier: terms of the form
  4405   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4406   are rewritten to
  4407   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4408   and those of the form
  4409   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4410   are rewritten to
  4411   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4412 
  4413 * HOL/datatype
  4414   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4415 
  4416   P(t_case f1 ... fn x) =
  4417      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4418         ...
  4419        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4420      )
  4421 
  4422   and a theorem `split_t_case_asm' of the form
  4423 
  4424   P(t_case f1 ... fn x) =
  4425     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4426         ...
  4427        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4428      )
  4429   which can be added to a simpset via `addsplits'. The existing theorems
  4430   expand_list_case and expand_option_case have been renamed to
  4431   split_list_case and split_option_case.
  4432 
  4433 * HOL/Arithmetic:
  4434   - `pred n' is automatically converted to `n-1'.
  4435     Users are strongly encouraged not to use `pred' any longer,
  4436     because it will disappear altogether at some point.
  4437   - Users are strongly encouraged to write "0 < n" rather than
  4438     "n ~= 0". Theorems and proof tools have been modified towards this
  4439     `standard'.
  4440 
  4441 * HOL/Lists:
  4442   the function "set_of_list" has been renamed "set" (and its theorems too);
  4443   the function "nth" now takes its arguments in the reverse order and
  4444   has acquired the infix notation "!" as in "xs!n".
  4445 
  4446 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4447 
  4448 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4449   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4450 
  4451 * HOL/record: extensible records with schematic structural subtyping
  4452 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4453 still lacks various theorems and concrete record syntax;
  4454 
  4455 
  4456 *** HOLCF ***
  4457 
  4458 * removed "axioms" and "generated by" sections;
  4459 
  4460 * replaced "ops" section by extended "consts" section, which is capable of
  4461   handling the continuous function space "->" directly;
  4462 
  4463 * domain package:
  4464   . proves theorems immediately and stores them in the theory,
  4465   . creates hierachical name space,
  4466   . now uses normal mixfix annotations (instead of cinfix...),
  4467   . minor changes to some names and values (for consistency),
  4468   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4469   . separator between mutual domain defs: changed "," to "and",
  4470   . improved handling of sort constraints;  now they have to
  4471     appear on the left-hand side of the equations only;
  4472 
  4473 * fixed LAM <x,y,zs>.b syntax;
  4474 
  4475 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4476 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4477 
  4478 
  4479 *** FOL and ZF ***
  4480 
  4481 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4482   with `addloop' of the simplifier to faciliate case splitting in premises.
  4483 
  4484 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4485 in HOL, they strip ALL and --> from proved theorems;
  4486 
  4487 
  4488 
  4489 New in Isabelle94-8 (May 1997)
  4490 ------------------------------
  4491 
  4492 *** General Changes ***
  4493 
  4494 * new utilities to build / run / maintain Isabelle etc. (in parts
  4495 still somewhat experimental); old Makefiles etc. still functional;
  4496 
  4497 * new 'Isabelle System Manual';
  4498 
  4499 * INSTALL text, together with ./configure and ./build scripts;
  4500 
  4501 * reimplemented type inference for greater efficiency, better error
  4502 messages and clean internal interface;
  4503 
  4504 * prlim command for dealing with lots of subgoals (an easier way of
  4505 setting goals_limit);
  4506 
  4507 
  4508 *** Syntax ***
  4509 
  4510 * supports alternative (named) syntax tables (parser and pretty
  4511 printer); internal interface is provided by add_modesyntax(_i);
  4512 
  4513 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4514 be used in conjunction with the Isabelle symbol font; uses the
  4515 "symbols" syntax table;
  4516 
  4517 * added token_translation interface (may translate name tokens in
  4518 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4519 the current print_mode); IMPORTANT: user print translation functions
  4520 are responsible for marking newly introduced bounds
  4521 (Syntax.mark_boundT);
  4522 
  4523 * token translations for modes "xterm" and "xterm_color" that display
  4524 names in bold, underline etc. or colors (which requires a color
  4525 version of xterm);
  4526 
  4527 * infixes may now be declared with names independent of their syntax;
  4528 
  4529 * added typed_print_translation (like print_translation, but may
  4530 access type of constant);
  4531 
  4532 
  4533 *** Classical Reasoner ***
  4534 
  4535 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4536 some limitations.  Blast_tac...
  4537   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4538   + ignores elimination rules that don't have the correct format
  4539         (the conclusion MUST be a formula variable)
  4540   + ignores types, which can make HOL proofs fail
  4541   + rules must not require higher-order unification, e.g. apply_type in ZF
  4542     [message "Function Var's argument not a bound variable" relates to this]
  4543   + its proof strategy is more general but can actually be slower
  4544 
  4545 * substitution with equality assumptions no longer permutes other
  4546 assumptions;
  4547 
  4548 * minor changes in semantics of addafter (now called addaltern); renamed
  4549 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4550 (and access functions for it);
  4551 
  4552 * improved combination of classical reasoner and simplifier:
  4553   + functions for handling clasimpsets
  4554   + improvement of addss: now the simplifier is called _after_ the
  4555     safe steps.
  4556   + safe variant of addss called addSss: uses safe simplifications
  4557     _during_ the safe steps. It is more complete as it allows multiple
  4558     instantiations of unknowns (e.g. with slow_tac).
  4559 
  4560 *** Simplifier ***
  4561 
  4562 * added interface for simplification procedures (functions that
  4563 produce *proven* rewrite rules on the fly, depending on current
  4564 redex);
  4565 
  4566 * ordering on terms as parameter (used for ordered rewriting);
  4567 
  4568 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4569 
  4570 * the solver is now split into a safe and an unsafe part.
  4571 This should be invisible for the normal user, except that the
  4572 functions setsolver and addsolver have been renamed to setSolver and
  4573 addSolver; added safe_asm_full_simp_tac;
  4574 
  4575 
  4576 *** HOL ***
  4577 
  4578 * a generic induction tactic `induct_tac' which works for all datatypes and
  4579 also for type `nat';
  4580 
  4581 * a generic case distinction tactic `exhaust_tac' which works for all
  4582 datatypes and also for type `nat';
  4583 
  4584 * each datatype comes with a function `size';
  4585 
  4586 * patterns in case expressions allow tuple patterns as arguments to
  4587 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4588 
  4589 * primrec now also works with type nat;
  4590 
  4591 * recdef: a new declaration form, allows general recursive functions to be
  4592 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4593 
  4594 * the constant for negation has been renamed from "not" to "Not" to
  4595 harmonize with FOL, ZF, LK, etc.;
  4596 
  4597 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4598 infinite lists;
  4599 
  4600 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4601 
  4602 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4603 problems in commutative rings, using axiomatic type classes for + and *;
  4604 
  4605 * more examples in HOL/MiniML and HOL/Auth;
  4606 
  4607 * more default rewrite rules for quantifiers, union/intersection;
  4608 
  4609 * a new constant `arbitrary == @x.False';
  4610 
  4611 * HOLCF/IOA replaces old HOL/IOA;
  4612 
  4613 * HOLCF changes: derived all rules and arities
  4614   + axiomatic type classes instead of classes
  4615   + typedef instead of faking type definitions
  4616   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4617   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4618   + eliminated the types void, one, tr
  4619   + use unit lift and bool lift (with translations) instead of one and tr
  4620   + eliminated blift from Lift3.thy (use Def instead of blift)
  4621   all eliminated rules are derived as theorems --> no visible changes ;
  4622 
  4623 
  4624 *** ZF ***
  4625 
  4626 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4627 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4628 as ZF_cs addSIs [equalityI];
  4629 
  4630 
  4631 
  4632 New in Isabelle94-7 (November 96)
  4633 ---------------------------------
  4634 
  4635 * allowing negative levels (as offsets) in prlev and choplev;
  4636 
  4637 * super-linear speedup for large simplifications;
  4638 
  4639 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4640 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4641 FAIL); can suppress it using the command Delsimps (ex_simps @
  4642 all_simps); De Morgan laws are also now included, by default;
  4643 
  4644 * improved printing of ==>  :  ~:
  4645 
  4646 * new object-logic "Sequents" adds linear logic, while replacing LK
  4647 and Modal (thanks to Sara Kalvala);
  4648 
  4649 * HOL/Auth: correctness proofs for authentication protocols;
  4650 
  4651 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4652 examples on HOL/Auth);
  4653 
  4654 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4655 the rewriter and classical reasoner simultaneously;
  4656 
  4657 * function uresult no longer returns theorems in "standard" format;
  4658 regain previous version by: val uresult = standard o uresult;
  4659 
  4660 
  4661 
  4662 New in Isabelle94-6
  4663 -------------------
  4664 
  4665 * oracles -- these establish an interface between Isabelle and trusted
  4666 external reasoners, which may deliver results as theorems;
  4667 
  4668 * proof objects (in particular record all uses of oracles);
  4669 
  4670 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4671 
  4672 * "constdefs" section in theory files;
  4673 
  4674 * "primrec" section (HOL) no longer requires names;
  4675 
  4676 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4677 
  4678 
  4679 
  4680 New in Isabelle94-5
  4681 -------------------
  4682 
  4683 * reduced space requirements;
  4684 
  4685 * automatic HTML generation from theories;
  4686 
  4687 * theory files no longer require "..." (quotes) around most types;
  4688 
  4689 * new examples, including two proofs of the Church-Rosser theorem;
  4690 
  4691 * non-curried (1994) version of HOL is no longer distributed;
  4692 
  4693 
  4694 
  4695 New in Isabelle94-4
  4696 -------------------
  4697 
  4698 * greatly reduced space requirements;
  4699 
  4700 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4701 
  4702 * searchable theorem database (see the section "Retrieving theorems" on
  4703 page 8 of the Reference Manual);
  4704 
  4705 * new examples, including Grabczewski's monumental case study of the
  4706 Axiom of Choice;
  4707 
  4708 * The previous version of HOL renamed to Old_HOL;
  4709 
  4710 * The new version of HOL (previously called CHOL) uses a curried syntax
  4711 for functions.  Application looks like f a b instead of f(a,b);
  4712 
  4713 * Mutually recursive inductive definitions finally work in HOL;
  4714 
  4715 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4716 translates to the operator "split";
  4717 
  4718 
  4719 
  4720 New in Isabelle94-3
  4721 -------------------
  4722 
  4723 * new infix operator, addss, allowing the classical reasoner to
  4724 perform simplification at each step of its search.  Example:
  4725         fast_tac (cs addss ss)
  4726 
  4727 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4728 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4729 look like (a,b) instead of <a,b>;
  4730 
  4731 * PLEASE NOTE: CHOL will eventually replace HOL!
  4732 
  4733 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4734 It translates to the operator "split".  A new theory of integers is available;
  4735 
  4736 * In ZF, integer numerals now denote two's-complement binary integers.
  4737 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4738 
  4739 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4740 of the Axiom of Choice;
  4741 
  4742 
  4743 
  4744 New in Isabelle94-2
  4745 -------------------
  4746 
  4747 * Significantly faster resolution;
  4748 
  4749 * the different sections in a .thy file can now be mixed and repeated
  4750 freely;
  4751 
  4752 * Database of theorems for FOL, HOL and ZF.  New
  4753 commands including qed, qed_goal and bind_thm store theorems in the database.
  4754 
  4755 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4756 a given theory (thms_of), or find out what theory a theorem was proved in
  4757 (theory_of_thm);
  4758 
  4759 * Bugs fixed in the inductive definition and datatype packages;
  4760 
  4761 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4762 and HOL_dup_cs obsolete;
  4763 
  4764 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4765 have been removed;
  4766 
  4767 * Simpler definition of function space in ZF;
  4768 
  4769 * new results about cardinal and ordinal arithmetic in ZF;
  4770 
  4771 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4772 types;
  4773 
  4774 
  4775 $Id$