NEWS
author nipkow
Sun Jun 03 13:19:03 2007 +0200 (2007-06-03)
changeset 23210 a0cb15114e7a
parent 23180 80b9caed2ba8
child 23251 471b576aad25
permissions -rw-r--r--
*** empty log message ***
     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 * new (input only) syntax for Haskell-like list comprehension, eg
   564   [(x,y). x <- xs, y <- ys, x ~= y]
   565   For details see List.thy.
   566 
   567 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   568     when generating code.
   569 
   570 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   571     when generating code.
   572 
   573 * Library/Commutative_Ring.thy: switched from recdef to function package;
   574     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   575 
   576 * Some steps towards more uniform lattice theory development in HOL.
   577 
   578     constants "meet" and "join" now named "inf" and "sup"
   579     constant "Meet" now named "Inf"
   580 
   581     classes "meet_semilorder" and "join_semilorder" now named
   582       "lower_semilattice" and "upper_semilattice"
   583     class "lorder" now named "lattice"
   584     class "comp_lat" now named "complete_lattice"
   585 
   586     Instantiation of lattice classes allows explicit definitions
   587     for "inf" and "sup" operations.
   588 
   589   INCOMPATIBILITY.  Theorem renames:
   590 
   591     meet_left_le            ~> inf_le1
   592     meet_right_le           ~> inf_le2
   593     join_left_le            ~> sup_ge1
   594     join_right_le           ~> sup_ge2
   595     meet_join_le            ~> inf_sup_ord
   596     le_meetI                ~> le_infI
   597     join_leI                ~> le_supI
   598     le_meet                 ~> le_inf_iff
   599     le_join                 ~> ge_sup_conv
   600     meet_idempotent         ~> inf_idem
   601     join_idempotent         ~> sup_idem
   602     meet_comm               ~> inf_commute
   603     join_comm               ~> sup_commute
   604     meet_leI1               ~> le_infI1
   605     meet_leI2               ~> le_infI2
   606     le_joinI1               ~> le_supI1
   607     le_joinI2               ~> le_supI2
   608     meet_assoc              ~> inf_assoc
   609     join_assoc              ~> sup_assoc
   610     meet_left_comm          ~> inf_left_commute
   611     meet_left_idempotent    ~> inf_left_idem
   612     join_left_comm          ~> sup_left_commute
   613     join_left_idempotent    ~> sup_left_idem
   614     meet_aci                ~> inf_aci
   615     join_aci                ~> sup_aci
   616     le_def_meet             ~> le_iff_inf
   617     le_def_join             ~> le_iff_sup
   618     join_absorp2            ~> sup_absorb2
   619     join_absorp1            ~> sup_absorb1
   620     meet_absorp1            ~> inf_absorb1
   621     meet_absorp2            ~> inf_absorb2
   622     meet_join_absorp        ~> inf_sup_absorb
   623     join_meet_absorp        ~> sup_inf_absorb
   624     distrib_join_le         ~> distrib_sup_le
   625     distrib_meet_le         ~> distrib_inf_le
   626 
   627     add_meet_distrib_left   ~> add_inf_distrib_left
   628     add_join_distrib_left   ~> add_sup_distrib_left
   629     is_join_neg_meet        ~> is_join_neg_inf
   630     is_meet_neg_join        ~> is_meet_neg_sup
   631     add_meet_distrib_right  ~> add_inf_distrib_right
   632     add_join_distrib_right  ~> add_sup_distrib_right
   633     add_meet_join_distribs  ~> add_sup_inf_distribs
   634     join_eq_neg_meet        ~> sup_eq_neg_inf
   635     meet_eq_neg_join        ~> inf_eq_neg_sup
   636     add_eq_meet_join        ~> add_eq_inf_sup
   637     meet_0_imp_0            ~> inf_0_imp_0
   638     join_0_imp_0            ~> sup_0_imp_0
   639     meet_0_eq_0             ~> inf_0_eq_0
   640     join_0_eq_0             ~> sup_0_eq_0
   641     neg_meet_eq_join        ~> neg_inf_eq_sup
   642     neg_join_eq_meet        ~> neg_sup_eq_inf
   643     join_eq_if              ~> sup_eq_if
   644 
   645     mono_meet               ~> mono_inf
   646     mono_join               ~> mono_sup
   647     meet_bool_eq            ~> inf_bool_eq
   648     join_bool_eq            ~> sup_bool_eq
   649     meet_fun_eq             ~> inf_fun_eq
   650     join_fun_eq             ~> sup_fun_eq
   651     meet_set_eq             ~> inf_set_eq
   652     join_set_eq             ~> sup_set_eq
   653     meet1_iff               ~> inf1_iff
   654     meet2_iff               ~> inf2_iff
   655     meet1I                  ~> inf1I
   656     meet2I                  ~> inf2I
   657     meet1D1                 ~> inf1D1
   658     meet2D1                 ~> inf2D1
   659     meet1D2                 ~> inf1D2
   660     meet2D2                 ~> inf2D2
   661     meet1E                  ~> inf1E
   662     meet2E                  ~> inf2E
   663     join1_iff               ~> sup1_iff
   664     join2_iff               ~> sup2_iff
   665     join1I1                 ~> sup1I1
   666     join2I1                 ~> sup2I1
   667     join1I1                 ~> sup1I1
   668     join2I2                 ~> sup1I2
   669     join1CI                 ~> sup1CI
   670     join2CI                 ~> sup2CI
   671     join1E                  ~> sup1E
   672     join2E                  ~> sup2E
   673 
   674     is_meet_Meet            ~> is_meet_Inf
   675     Meet_bool_def           ~> Inf_bool_def
   676     Meet_fun_def            ~> Inf_fun_def
   677     Meet_greatest           ~> Inf_greatest
   678     Meet_lower              ~> Inf_lower
   679     Meet_set_def            ~> Inf_set_def
   680 
   681     listsp_meetI            ~> listsp_infI
   682     listsp_meet_eq          ~> listsp_inf_eq
   683 
   684     meet_min                ~> inf_min
   685     join_max                ~> sup_max
   686 
   687 * Classes "order" and "linorder": facts "refl", "trans" and
   688 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   689 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   690 
   691 * Classes "order" and "linorder": 
   692 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   693 proofs changed.
   694 
   695 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   696 INCOMPATIBILITY.
   697 
   698 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   699 INCOMPATIBILITY.
   700 
   701 * Added syntactic class "size"; overloaded constant "size" now has
   702 type "'a::size ==> bool"
   703 
   704 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   705 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   706 
   707 * Added method "lexicographic_order" automatically synthesizes
   708 termination relations as lexicographic combinations of size measures
   709 -- 'function' package.
   710 
   711 * HOL/records: generalised field-update to take a function on the
   712 field rather than the new value: r(|A := x|) is translated to A_update
   713 (K x) r The K-combinator that is internally used is called K_record.
   714 INCOMPATIBILITY: Usage of the plain update functions has to be
   715 adapted.
   716  
   717 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   718 0 * x = 0, which are required for a semiring.  Richer structures do
   719 not inherit from semiring_0 anymore, because this property is a
   720 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   721 semiring_0, there is more to prove, but this is mostly trivial.
   722 
   723 * axclass "recpower" was generalized to arbitrary monoids, not just
   724 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   725 commutativity or a semiring property, add the corresponding classes.
   726 
   727 * Unified locale partial_order with class definition (cf. theory
   728 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   729 
   730 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   731 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   732 Isar level, use abbreviations instead.
   733 
   734 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   735 rarely occuring name references (e.g. ``List.op mem.simps'') require
   736 renaming (e.g. ``List.memberl.simps'').
   737 
   738 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   739 INCOMPATIBILITY.
   740 
   741 * Added theory Code_Generator providing class 'eq', allowing for code
   742 generation with polymorphic equality.
   743 
   744 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   745 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   746 significant changes for setting up numeral syntax for types:
   747 
   748   - new constants Numeral.pred and Numeral.succ instead
   749       of former Numeral.bin_pred and Numeral.bin_succ.
   750   - Use integer operations instead of bin_add, bin_mult and so on.
   751   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   752   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   753 
   754 See HOL/Integ/IntArith.thy for an example setup.
   755 
   756 * New top level command 'normal_form' computes the normal form of a
   757 term that may contain free variables. For example ``normal_form
   758 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   759 suitable for heavy-duty computations because the functions are
   760 compiled to ML first.
   761 
   762 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   763 25 like -->); output depends on the "iff" print_mode, the default is
   764 "A = B" (with priority 50).
   765 
   766 * Renamed constants in HOL.thy and Orderings.thy:
   767     op +   ~> HOL.plus_class.plus
   768     op -   ~> HOL.minus_class.minus
   769     uminus ~> HOL.minus_class.uminus
   770     op *   ~> HOL.times_class.times
   771     op <   ~> Orderings.ord_class.less
   772     op <=  ~> Orderings.ord_class.less_eq
   773 
   774 Adaptions may be required in the following cases:
   775 
   776 a) User-defined constants using any of the names "plus", "minus", "times",
   777 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   778 may go wrong.
   779 INCOMPATIBILITY: use more specific names.
   780 
   781 b) Variables named "plus", "minus", "times", "less", "less_eq"
   782 INCOMPATIBILITY: use more specific names.
   783 
   784 c) Permutative equations (e.g. "a + b = b + a")
   785 Since the change of names also changes the order of terms, permutative
   786 rewrite rules may get applied in a different order. Experience shows that
   787 this is rarely the case (only two adaptions in the whole Isabelle
   788 distribution).
   789 INCOMPATIBILITY: rewrite proofs
   790 
   791 d) ML code directly refering to constant names
   792 This in general only affects hand-written proof tactics, simprocs and so on.
   793 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   794 of const_name ML antiquotations.
   795 
   796 * Relations less (<) and less_eq (<=) are also available on type bool.
   797 Modified syntax to disallow nesting without explicit parentheses,
   798 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   799 
   800 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   801 
   802 * Relation composition operator "op O" now has precedence 75 and binds
   803 stronger than union and intersection. INCOMPATIBILITY.
   804 
   805 * The old set interval syntax "{m..n(}" (and relatives) has been
   806 removed.  Use "{m..<n}" (and relatives) instead.
   807 
   808 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   809 "t = s" to False (by simproc "neq_simproc").  For backward
   810 compatibility this can be disabled by ML "reset use_neq_simproc".
   811 
   812 * "m dvd n" where m and n are numbers is evaluated to True/False by
   813 simp.
   814 
   815 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   816 
   817 * Theorem setsum_mult renamed to setsum_right_distrib.
   818 
   819 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   820 ``rule'' method.
   821 
   822 * Reimplemented methods ``sat'' and ``satx'', with several
   823 improvements: goals no longer need to be stated as "<prems> ==>
   824 False", equivalences (i.e. "=" on type bool) are handled, variable
   825 names of the form "lit_<n>" are no longer reserved, significant
   826 speedup.
   827 
   828 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   829 zChaff is still supported as well.
   830 
   831 * 'inductive' and 'datatype': provide projections of mutual rules,
   832 bundled as foo_bar.inducts;
   833 
   834 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   835 Library.
   836 
   837 * Library: moved theory Accessible_Part to main HOL.
   838 
   839 * Library: added theory Coinductive_List of potentially infinite lists
   840 as greatest fixed-point.
   841 
   842 * Library: added theory AssocList which implements (finite) maps as
   843 association lists.
   844 
   845 * Added proof method ``evaluation'' for efficiently solving a goal
   846 (i.e. a boolean expression) by compiling it to ML. The goal is
   847 "proved" (via an oracle) if it evaluates to True.
   848 
   849 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   850 also when invoked by the simplifier.  This results in the simplifier
   851 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   852 fast_arith_split_limit to 0 to obtain the old behavior.
   853 
   854 * Support for hex (0x20) and binary (0b1001) numerals.
   855 
   856 * New method: reify eqs (t), where eqs are equations for an
   857 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   858 parameter, computes a term s::'b and a list xs::'a list and proves the
   859 theorem I xs s = t. This is also known as reification or quoting. The
   860 resulting theorem is applied to the subgoal to substitute t with I xs
   861 s.  If t is omitted, the subgoal itself is reified.
   862 
   863 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   864 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   865 where f is supposed to be a computable function (in the sense of code
   866 generattion). The method uses reify to compute s and xs as above then
   867 applies corr_thm and uses normalization by evaluation to "prove" f s =
   868 r and finally gets the theorem t = r, which is again applied to the
   869 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   870 
   871 * Reflection: Automatic refification now handels binding, an example
   872 is available in HOL/ex/ReflectionEx.thy
   873 
   874 
   875 *** HOL-Algebra ***
   876 
   877 * Formalisation of ideals and the quotient construction over rings.
   878 
   879 * Order and lattice theory no longer based on records.
   880 INCOMPATIBILITY.
   881 
   882 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   883 greatest_closed.  INCOMPATIBILITY.
   884 
   885 * Method algebra is now set up via an attribute.  For examples see
   886 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   887 of algebraic structures.
   888 
   889 * Renamed theory CRing to Ring.
   890 
   891 
   892 *** HOL-Complex ***
   893 
   894 * Theory Real: new method ferrack implements quantifier elimination
   895 for linear arithmetic over the reals. The quantifier elimination
   896 feature is used only for decision, for compatibility with arith. This
   897 means a goal is either solved or left unchanged, no simplification.
   898 
   899 * Hyperreal: Functions root and sqrt are now defined on negative real
   900 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
   901 Nonnegativity side conditions have been removed from many lemmas, so
   902 that more subgoals may now be solved by simplification; potential
   903 INCOMPATIBILITY.
   904 
   905 * Real: New axiomatic classes formalize real normed vector spaces and
   906 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   907 and norm :: 'a => real.
   908 
   909 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   910 from reals into other types. The overloaded constant Reals :: 'a set
   911 is now defined as range of_real; potential INCOMPATIBILITY.
   912 
   913 * Real: ML code generation is supported now and hence also quickcheck.
   914 Reals are implemented as arbitrary precision rationals.
   915 
   916 * Hyperreal: Several constants that previously worked only for the
   917 reals have been generalized, so they now work over arbitrary vector
   918 spaces. Type annotations may need to be added in some cases; potential
   919 INCOMPATIBILITY.
   920 
   921   Infinitesimal  :: ('a::real_normed_vector) star set
   922   HFinite        :: ('a::real_normed_vector) star set
   923   HInfinite      :: ('a::real_normed_vector) star set
   924   approx         :: ('a::real_normed_vector) star => 'a star => bool
   925   monad          :: ('a::real_normed_vector) star => 'a star set
   926   galaxy         :: ('a::real_normed_vector) star => 'a star set
   927   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
   928   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   929   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   930   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   931   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   932   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   933   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   934   sgn            :: 'a::real_normed_vector => 'a
   935   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
   936 
   937 * Complex: Some complex-specific constants are now abbreviations for
   938 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   939 hnorm.  Other constants have been entirely removed in favor of the
   940 polymorphic versions (INCOMPATIBILITY):
   941 
   942   approx        <-- capprox
   943   HFinite       <-- CFinite
   944   HInfinite     <-- CInfinite
   945   Infinitesimal <-- CInfinitesimal
   946   monad         <-- cmonad
   947   galaxy        <-- cgalaxy
   948   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   949   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   950   (ns)deriv     <-- (ns)cderiv
   951 
   952 
   953 *** ML ***
   954 
   955 * Context data interfaces (Theory/Proof/GenericDataFun): removed
   956 name/print, uninitialized data defaults to ad-hoc copy of empty value,
   957 init only required for impure data.  INCOMPATIBILITY: empty really
   958 need to be empty (no dependencies on theory content!)
   959 
   960 * ML within Isar: antiquotations allow to embed statically-checked
   961 formal entities in the source, referring to the context available at
   962 compile-time.  For example:
   963 
   964 ML {* @{typ "'a => 'b"} *}
   965 ML {* @{term "%x. x"} *}
   966 ML {* @{prop "x == y"} *}
   967 ML {* @{ctyp "'a => 'b"} *}
   968 ML {* @{cterm "%x. x"} *}
   969 ML {* @{cprop "x == y"} *}
   970 ML {* @{thm asm_rl} *}
   971 ML {* @{thms asm_rl} *}
   972 ML {* @{const_name c} *}
   973 ML {* @{const_syntax c} *}
   974 ML {* @{context} *}
   975 ML {* @{theory} *}
   976 ML {* @{theory Pure} *}
   977 ML {* @{simpset} *}
   978 ML {* @{claset} *}
   979 ML {* @{clasimpset} *}
   980 
   981 The same works for sources being ``used'' within an Isar context.
   982 
   983 * ML in Isar: improved error reporting; extra verbosity with
   984 Toplevel.debug enabled.
   985 
   986 * Pure/library:
   987 
   988   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   989   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   990 
   991 The semantics of "burrow" is: "take a function with *simulatanously*
   992 transforms a list of value, and apply it *simulatanously* to a list of
   993 list of values of the appropriate type". Compare this with "map" which
   994 would *not* apply its argument function simulatanously but in
   995 sequence; "fold_burrow" has an additional context.
   996 
   997 * Pure/library: functions map2 and fold2 with curried syntax for
   998 simultanous mapping and folding:
   999 
  1000     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1001     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1002 
  1003 * Pure/library: indexed lists - some functions in the Isabelle library
  1004 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1005 given more convenient names and signatures reminiscent of similar
  1006 functions for alists, tables, etc:
  1007 
  1008   val nth: 'a list -> int -> 'a 
  1009   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1010   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1011 
  1012 Note that fold_index starts counting at index 0, not 1 like foldln
  1013 used to.
  1014 
  1015 * Pure/library: added general ``divide_and_conquer'' combinator on
  1016 lists.
  1017 
  1018 * Pure/General/table.ML: the join operations now works via exceptions
  1019 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1020 admits slightly more efficient complex applications.
  1021 
  1022 * Pure: datatype Context.generic joins theory/Proof.context and
  1023 provides some facilities for code that works in either kind of
  1024 context, notably GenericDataFun for uniform theory and proof data.
  1025 
  1026 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1027 use Context.generic instead of just theory.
  1028 
  1029 * Pure: simplified internal attribute type, which is now always
  1030 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1031 vs. local (Proof.context) attributes have been discontinued, while
  1032 minimizing code duplication.  Thm.rule_attribute and
  1033 Thm.declaration_attribute build canonical attributes; see also
  1034 structure Context for further operations on Context.generic, notably
  1035 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1036 declarations and definitions.
  1037 
  1038 * Pure/kernel: consts certification ignores sort constraints given in
  1039 signature declarations.  (This information is not relevant to the
  1040 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1041 potential INCOMPATIBILITY.
  1042 
  1043 * Pure: axiomatic type classes are now purely definitional, with
  1044 explicit proofs of class axioms and super class relations performed
  1045 internally.  See Pure/axclass.ML for the main internal interfaces --
  1046 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1047 AxClass.axiomatize_class/classrel/arity supercede
  1048 Sign.add_classes/classrel/arities.
  1049 
  1050 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1051 global/local versions on theory vs. Proof.context have been
  1052 discontinued; Attrib.syntax and Method.syntax have been adapted
  1053 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1054 attributes, methods, etc.
  1055 
  1056 * Pure: several functions of signature "... -> theory -> theory * ..."
  1057 have been reoriented to "... -> theory -> ... * theory" in order to
  1058 allow natural usage in combination with the ||>, ||>>, |-> and
  1059 fold_map combinators.
  1060 
  1061 * Pure: official theorem names (closed derivations) and additional
  1062 comments (tags) are now strictly separate.  Name hints -- which are
  1063 maintained as tags -- may be attached any time without affecting the
  1064 derivation.
  1065 
  1066 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1067 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1068 achieve the old behaviour.
  1069 
  1070 * Pure: the "Goal" constant is now called "prop", supporting a
  1071 slightly more general idea of ``protecting'' meta-level rule
  1072 statements.
  1073 
  1074 * Pure: Logic.(un)varify only works in a global context, which is now
  1075 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1076 Logic.legacy_(un)varify as temporary workaround.
  1077 
  1078 * Pure: structure Name provides scalable operations for generating
  1079 internal variable names, notably Name.variants etc.  This replaces
  1080 some popular functions from term.ML:
  1081 
  1082   Term.variant		->  Name.variant
  1083   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1084   Term.invent_names	->  Name.invent_list
  1085 
  1086 Note that low-level renaming rarely occurs in new code -- operations
  1087 from structure Variable are used instead (see below).
  1088 
  1089 * Pure: structure Variable provides fundamental operations for proper
  1090 treatment of fixed/schematic variables in a context.  For example,
  1091 Variable.import introduces fixes for schematics of given facts and
  1092 Variable.export reverses the effect (up to renaming) -- this replaces
  1093 various freeze_thaw operations.
  1094 
  1095 * Pure: structure Goal provides simple interfaces for
  1096 init/conclude/finish and tactical prove operations (replacing former
  1097 Tactic.prove).  Goal.prove is the canonical way to prove results
  1098 within a given context; Goal.prove_global is a degraded version for
  1099 theory level goals, including a global Drule.standard.  Note that
  1100 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1101 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1102 in a locale context).
  1103 
  1104 * Isar: simplified treatment of user-level errors, using exception
  1105 ERROR of string uniformly.  Function error now merely raises ERROR,
  1106 without any side effect on output channels.  The Isar toplevel takes
  1107 care of proper display of ERROR exceptions.  ML code may use plain
  1108 handle/can/try; cat_error may be used to concatenate errors like this:
  1109 
  1110   ... handle ERROR msg => cat_error msg "..."
  1111 
  1112 Toplevel ML code (run directly or through the Isar toplevel) may be
  1113 embedded into the Isar toplevel with exception display/debug like
  1114 this:
  1115 
  1116   Isar.toplevel (fn () => ...)
  1117 
  1118 INCOMPATIBILITY, removed special transform_error facilities, removed
  1119 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1120 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1121 -- use plain ERROR instead.
  1122 
  1123 * Isar: theory setup now has type (theory -> theory), instead of a
  1124 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1125 
  1126 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1127 subject to ProofContext.debug/verbose flags.
  1128 
  1129 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1130 theory before entering a proof state.  Transactions now always see a
  1131 quasi-functional intermediate checkpoint, both in interactive and
  1132 batch mode.
  1133 
  1134 * Simplifier: the simpset of a running simplification process now
  1135 contains a proof context (cf. Simplifier.the_context), which is the
  1136 very context that the initial simpset has been retrieved from (by
  1137 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1138 (solver, looper etc.) may depend on arbitrary proof data.
  1139 
  1140 * Simplifier.inherit_context inherits the proof context (plus the
  1141 local bounds) of the current simplification process; any simproc
  1142 etc. that calls the Simplifier recursively should do this!  Removed
  1143 former Simplifier.inherit_bounds, which is already included here --
  1144 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1145 specify an explicit context using Simplifier.context/theory_context.
  1146 
  1147 * Simplifier/Classical Reasoner: more abstract interfaces
  1148 change_simpset/claset for modifying the simpset/claset reference of a
  1149 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1150 INCOMPATIBILITY.
  1151 
  1152 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1153 "Trueprop" etc.
  1154 
  1155 
  1156 *** System ***
  1157 
  1158 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1159 locations -- now includes the Isabelle version identifier as well.
  1160 This simplifies use of multiple Isabelle installations.
  1161 
  1162 * isabelle-process: option -S (secure mode) disables some critical
  1163 operations, notably runtime compilation and evaluation of ML source
  1164 code.
  1165 
  1166 
  1167 New in Isabelle2005 (October 2005)
  1168 ----------------------------------
  1169 
  1170 *** General ***
  1171 
  1172 * Theory headers: the new header syntax for Isar theories is
  1173 
  1174   theory <name>
  1175   imports <theory1> ... <theoryN>
  1176   uses <file1> ... <fileM>
  1177   begin
  1178 
  1179 where the 'uses' part is optional.  The previous syntax
  1180 
  1181   theory <name> = <theory1> + ... + <theoryN>:
  1182 
  1183 will disappear in the next release.  Use isatool fixheaders to convert
  1184 existing theory files.  Note that there is no change in ancient
  1185 non-Isar theories now, but these will disappear soon.
  1186 
  1187 * Theory loader: parent theories can now also be referred to via
  1188 relative and absolute paths.
  1189 
  1190 * Command 'find_theorems' searches for a list of criteria instead of a
  1191 list of constants. Known criteria are: intro, elim, dest, name:string,
  1192 simp:term, and any term. Criteria can be preceded by '-' to select
  1193 theorems that do not match. Intro, elim, dest select theorems that
  1194 match the current goal, name:s selects theorems whose fully qualified
  1195 name contain s, and simp:term selects all simplification rules whose
  1196 lhs match term.  Any other term is interpreted as pattern and selects
  1197 all theorems matching the pattern. Available in ProofGeneral under
  1198 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1199 
  1200   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1201 
  1202 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1203 matching the current goal as introduction rule and not having "HOL."
  1204 in their name (i.e. not being defined in theory HOL).
  1205 
  1206 * Command 'thms_containing' has been discontinued in favour of
  1207 'find_theorems'; INCOMPATIBILITY.
  1208 
  1209 * Communication with Proof General is now 8bit clean, which means that
  1210 Unicode text in UTF-8 encoding may be used within theory texts (both
  1211 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1212 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1213 
  1214   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1215   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1216 
  1217 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1218 Classical Reasoner.  Typical big applications run around 2 times
  1219 faster.
  1220 
  1221 
  1222 *** Document preparation ***
  1223 
  1224 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1225 of raw sources.  Only those symbols that do not require additional
  1226 LaTeX packages (depending on comments in isabellesym.sty) are
  1227 displayed properly, everything else is left verbatim.  isatool display
  1228 and isatool print are used as front ends (these are subject to the
  1229 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1230 
  1231 * Command tags control specific markup of certain regions of text,
  1232 notably folding and hiding.  Predefined tags include "theory" (for
  1233 theory begin and end), "proof" for proof commands, and "ML" for
  1234 commands involving ML code; the additional tags "visible" and
  1235 "invisible" are unused by default.  Users may give explicit tag
  1236 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1237 interpretation of tags is determined by the LaTeX job during document
  1238 preparation: see option -V of isatool usedir, or options -n and -t of
  1239 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1240 \isadroptag.
  1241 
  1242 Several document versions may be produced at the same time via isatool
  1243 usedir (the generated index.html will link all of them).  Typical
  1244 specifications include ''-V document=theory,proof,ML'' to present
  1245 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1246 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1247 these parts without any formal replacement text.  The Isabelle site
  1248 default settings produce ''document'' and ''outline'' versions as
  1249 specified above.
  1250 
  1251 * Several new antiquotations:
  1252 
  1253   @{term_type term} prints a term with its type annotated;
  1254 
  1255   @{typeof term} prints the type of a term;
  1256 
  1257   @{const const} is the same as @{term const}, but checks that the
  1258   argument is a known logical constant;
  1259 
  1260   @{term_style style term} and @{thm_style style thm} print a term or
  1261   theorem applying a "style" to it
  1262 
  1263   @{ML text}
  1264 
  1265 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1266 definitions, equations, inequations etc., 'concl' printing only the
  1267 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1268 to print the specified premise.  TermStyle.add_style provides an ML
  1269 interface for introducing further styles.  See also the "LaTeX Sugar"
  1270 document practical applications.  The ML antiquotation prints
  1271 type-checked ML expressions verbatim.
  1272 
  1273 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1274 and 'text' support optional locale specification '(in loc)', which
  1275 specifies the default context for interpreting antiquotations.  For
  1276 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1277 
  1278 * Option 'locale=NAME' of antiquotations specifies an alternative
  1279 context interpreting the subsequent argument.  For example: @{thm
  1280 [locale=lattice] inf_assoc}.
  1281 
  1282 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1283 a proof context.
  1284 
  1285 * Proper output of antiquotations for theory commands involving a
  1286 proof context (such as 'locale' or 'theorem (in loc) ...').
  1287 
  1288 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1289 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1290 
  1291 * isatool usedir: new option -C (default true) controls whether option
  1292 -D should include a copy of the original document directory; -C false
  1293 prevents unwanted effects such as copying of administrative CVS data.
  1294 
  1295 
  1296 *** Pure ***
  1297 
  1298 * Considerably improved version of 'constdefs' command.  Now performs
  1299 automatic type-inference of declared constants; additional support for
  1300 local structure declarations (cf. locales and HOL records), see also
  1301 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1302 sequential dependencies of definitions within a single 'constdefs'
  1303 section; moreover, the declared name needs to be an identifier.  If
  1304 all fails, consider to fall back on 'consts' and 'defs' separately.
  1305 
  1306 * Improved indexed syntax and implicit structures.  First of all,
  1307 indexed syntax provides a notational device for subscripted
  1308 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1309 expressions.  Secondly, in a local context with structure
  1310 declarations, number indexes \<^sub>n or the empty index (default
  1311 number 1) refer to a certain fixed variable implicitly; option
  1312 show_structs controls printing of implicit structures.  Typical
  1313 applications of these concepts involve record types and locales.
  1314 
  1315 * New command 'no_syntax' removes grammar declarations (and
  1316 translations) resulting from the given syntax specification, which is
  1317 interpreted in the same manner as for the 'syntax' command.
  1318 
  1319 * 'Advanced' translation functions (parse_translation etc.) may depend
  1320 on the signature of the theory context being presently used for
  1321 parsing/printing, see also isar-ref manual.
  1322 
  1323 * Improved 'oracle' command provides a type-safe interface to turn an
  1324 ML expression of type theory -> T -> term into a primitive rule of
  1325 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1326 is already included here); see also FOL/ex/IffExample.thy;
  1327 INCOMPATIBILITY.
  1328 
  1329 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1330 before); "cI" is no longer bound, use "c.intro" instead.
  1331 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1332 axclasses vs. locales.
  1333 
  1334 * Improved internal renaming of symbolic identifiers -- attach primes
  1335 instead of base 26 numbers.
  1336 
  1337 * New flag show_question_marks controls printing of leading question
  1338 marks in schematic variable names.
  1339 
  1340 * In schematic variable names, *any* symbol following \<^isub> or
  1341 \<^isup> is now treated as part of the base name.  For example, the
  1342 following works without printing of awkward ".0" indexes:
  1343 
  1344   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1345     by simp
  1346 
  1347 * Inner syntax includes (*(*nested*) comments*).
  1348 
  1349 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1350 annotations as "(00...)".
  1351 
  1352 * Clear separation of logical types and nonterminals, where the latter
  1353 may only occur in 'syntax' specifications or type abbreviations.
  1354 Before that distinction was only partially implemented via type class
  1355 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1356 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1357 exotic syntax specifications may require further adaption
  1358 (e.g. Cube/Cube.thy).
  1359 
  1360 * Removed obsolete type class "logic", use the top sort {} instead.
  1361 Note that non-logical types should be declared as 'nonterminals'
  1362 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1363 specifications.
  1364 
  1365 * Attributes 'induct' and 'cases': type or set names may now be
  1366 locally fixed variables as well.
  1367 
  1368 * Simplifier: can now control the depth to which conditional rewriting
  1369 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1370 Limit.
  1371 
  1372 * Simplifier: simplification procedures may now take the current
  1373 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1374 interface), which is very useful for calling the Simplifier
  1375 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1376 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1377 low-level mk_simproc no longer applies Logic.varify internally, to
  1378 allow for use in a context of fixed variables.
  1379 
  1380 * thin_tac now works even if the assumption being deleted contains !!
  1381 or ==>.  More generally, erule now works even if the major premise of
  1382 the elimination rule contains !! or ==>.
  1383 
  1384 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1385 
  1386 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1387 from Pure, which contains all common declarations already.  Both
  1388 theories are defined via plain Isabelle/Isar .thy files.
  1389 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1390 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1391 use isatool fixcpure to adapt your theory and ML sources.
  1392 
  1393 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1394 selections of theorems in named facts via index ranges.
  1395 
  1396 * 'print_theorems': in theory mode, really print the difference
  1397 wrt. the last state (works for interactive theory development only),
  1398 in proof mode print all local facts (cf. 'print_facts');
  1399 
  1400 * 'hide': option '(open)' hides only base names.
  1401 
  1402 * More efficient treatment of intermediate checkpoints in interactive
  1403 theory development.
  1404 
  1405 * Code generator is now invoked via code_module (incremental code
  1406 generation) and code_library (modular code generation, ML structures
  1407 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1408 must be quoted when used as identifiers.
  1409 
  1410 * New 'value' command for reading, evaluating and printing terms using
  1411 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1412 quoted when used as identifier.
  1413 
  1414 
  1415 *** Locales ***
  1416 
  1417 * New commands for the interpretation of locale expressions in
  1418 theories (1), locales (2) and proof contexts (3).  These generate
  1419 proof obligations from the expression specification.  After the
  1420 obligations have been discharged, theorems of the expression are added
  1421 to the theory, target locale or proof context.  The synopsis of the
  1422 commands is a follows:
  1423 
  1424   (1) interpretation expr inst
  1425   (2) interpretation target < expr
  1426   (3) interpret expr inst
  1427 
  1428 Interpretation in theories and proof contexts require a parameter
  1429 instantiation of terms from the current context.  This is applied to
  1430 specifications and theorems of the interpreted expression.
  1431 Interpretation in locales only permits parameter renaming through the
  1432 locale expression.  Interpretation is smart in that interpretations
  1433 that are active already do not occur in proof obligations, neither are
  1434 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1435 inspect active interpretations of a particular locale.  For details,
  1436 see the Isar Reference manual.  Examples can be found in
  1437 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1438 
  1439 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1440 'interpret' instead.
  1441 
  1442 * New context element 'constrains' for adding type constraints to
  1443 parameters.
  1444 
  1445 * Context expressions: renaming of parameters with syntax
  1446 redeclaration.
  1447 
  1448 * Locale declaration: 'includes' disallowed.
  1449 
  1450 * Proper static binding of attribute syntax -- i.e. types / terms /
  1451 facts mentioned as arguments are always those of the locale definition
  1452 context, independently of the context of later invocations.  Moreover,
  1453 locale operations (renaming and type / term instantiation) are applied
  1454 to attribute arguments as expected.
  1455 
  1456 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1457 actual attributes; rare situations may require Attrib.attribute to
  1458 embed those attributes into Attrib.src that lack concrete syntax.
  1459 Attribute implementations need to cooperate properly with the static
  1460 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1461 Attrib.XXX_thm etc. already do the right thing without further
  1462 intervention.  Only unusual applications -- such as "where" or "of"
  1463 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1464 on the context and the facts involved -- may have to assign parsed
  1465 values to argument tokens explicitly.
  1466 
  1467 * Changed parameter management in theorem generation for long goal
  1468 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1469 theorem statement in rare situations.
  1470 
  1471 * Locale inspection command 'print_locale' omits notes elements.  Use
  1472 'print_locale!' to have them included in the output.
  1473 
  1474 
  1475 *** Provers ***
  1476 
  1477 * Provers/hypsubst.ML: improved version of the subst method, for
  1478 single-step rewriting: it now works in bound variable contexts. New is
  1479 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1480 rewrite a different subterm than the original subst method, which is
  1481 still available as 'simplesubst'.
  1482 
  1483 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1484 and quasi orders.
  1485 
  1486 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1487 reflexive-transitive closure of relations.
  1488 
  1489 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1490 limit (previously hard-coded with a value of 20) user-definable.
  1491 
  1492 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1493 is peformed already.  Object-logics merely need to finish their
  1494 initial simpset configuration as before.  INCOMPATIBILITY.
  1495 
  1496 
  1497 *** HOL ***
  1498 
  1499 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1500 
  1501   syntax (epsilon)
  1502     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1503 
  1504 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1505 and x-symbol; use option '-m epsilon' to get it actually printed.
  1506 Moreover, the mathematically important symbolic identifier \<epsilon>
  1507 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1508 
  1509 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1510 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1511 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1512 support corresponding Isar calculations.
  1513 
  1514 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1515 instead of ":".
  1516 
  1517 * theory SetInterval: changed the syntax for open intervals:
  1518 
  1519   Old       New
  1520   {..n(}    {..<n}
  1521   {)n..}    {n<..}
  1522   {m..n(}   {m..<n}
  1523   {)m..n}   {m<..n}
  1524   {)m..n(}  {m<..<n}
  1525 
  1526 The old syntax is still supported but will disappear in the next
  1527 release.  For conversion use the following Emacs search and replace
  1528 patterns (these are not perfect but work quite well):
  1529 
  1530   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1531   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1532 
  1533 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1534 equalities in commutative rings; method 'algebra' provides a generic
  1535 interface.
  1536 
  1537 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1538 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1539 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1540 be a tuple pattern.
  1541 
  1542 Some new syntax forms are available:
  1543 
  1544   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1545   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1546   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1547   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1548 
  1549 The latter form "\<Sum>x < k. e" used to be based on a separate
  1550 function "Summation", which has been discontinued.
  1551 
  1552 * theory Finite_Set: in structured induction proofs, the insert case
  1553 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1554 (insert F x)'.
  1555 
  1556 * The 'refute' command has been extended to support a much larger
  1557 fragment of HOL, including axiomatic type classes, constdefs and
  1558 typedefs, inductive datatypes and recursion.
  1559 
  1560 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1561 Requires zChaff with proof generation to be installed.  See
  1562 HOL/ex/SAT_Examples.thy for examples.
  1563 
  1564 * Datatype induction via method 'induct' now preserves the name of the
  1565 induction variable. For example, when proving P(xs::'a list) by
  1566 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1567 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1568 in unstructured proof scripts.
  1569 
  1570 * Reworked implementation of records.  Improved scalability for
  1571 records with many fields, avoiding performance problems for type
  1572 inference. Records are no longer composed of nested field types, but
  1573 of nested extension types. Therefore the record type only grows linear
  1574 in the number of extensions and not in the number of fields.  The
  1575 top-level (users) view on records is preserved.  Potential
  1576 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1577 old record representation. The type generated for a record is called
  1578 <record_name>_ext_type.
  1579 
  1580 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1581 proofs triggered by a record definition or a simproc (if
  1582 quick_and_dirty is enabled).  Definitions of large records can take
  1583 quite long.
  1584 
  1585 New simproc record_upd_simproc for simplification of multiple record
  1586 updates enabled by default.  Moreover, trivial updates are also
  1587 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1588 occasionally, since simplification is more powerful by default.
  1589 
  1590 * typedef: proper support for polymorphic sets, which contain extra
  1591 type-variables in the term.
  1592 
  1593 * Simplifier: automatically reasons about transitivity chains
  1594 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1595 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1596 old proofs break occasionally as simplification may now solve more
  1597 goals than previously.
  1598 
  1599 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1600 present.  Works for all partial orders (class "order"), in particular
  1601 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1602 just like y <= x.
  1603 
  1604 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1605 bound variable or a constant then the let is unfolded.  Otherwise
  1606 first a is simplified to b, and then f b is simplified to g. If
  1607 possible we abstract b from g arriving at "let x = b in h x",
  1608 otherwise we unfold the let and arrive at g.  The simproc can be
  1609 enabled/disabled by the reference use_let_simproc.  Potential
  1610 INCOMPATIBILITY since simplification is more powerful by default.
  1611 
  1612 * Classical reasoning: the meson method now accepts theorems as arguments.
  1613 
  1614 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1615 jobs to provide advice on the provability of subgoals.
  1616 
  1617 * Theory OrderedGroup and Ring_and_Field: various additions and
  1618 improvements to faciliate calculations involving equalities and
  1619 inequalities.
  1620 
  1621 The following theorems have been eliminated or modified
  1622 (INCOMPATIBILITY):
  1623 
  1624   abs_eq             now named abs_of_nonneg
  1625   abs_of_ge_0        now named abs_of_nonneg
  1626   abs_minus_eq       now named abs_of_nonpos
  1627   imp_abs_id         now named abs_of_nonneg
  1628   imp_abs_neg_id     now named abs_of_nonpos
  1629   mult_pos           now named mult_pos_pos
  1630   mult_pos_le        now named mult_nonneg_nonneg
  1631   mult_pos_neg_le    now named mult_nonneg_nonpos
  1632   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1633   mult_neg           now named mult_neg_neg
  1634   mult_neg_le        now named mult_nonpos_nonpos
  1635 
  1636 * Theory Parity: added rules for simplifying exponents.
  1637 
  1638 * Theory List:
  1639 
  1640 The following theorems have been eliminated or modified
  1641 (INCOMPATIBILITY):
  1642 
  1643   list_all_Nil       now named list_all.simps(1)
  1644   list_all_Cons      now named list_all.simps(2)
  1645   list_all_conv      now named list_all_iff
  1646   set_mem_eq         now named mem_iff
  1647 
  1648 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1649 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1650 
  1651 
  1652 *** HOL-Complex ***
  1653 
  1654 * Theory RealDef: better support for embedding natural numbers and
  1655 integers in the reals.
  1656 
  1657 The following theorems have been eliminated or modified
  1658 (INCOMPATIBILITY):
  1659 
  1660   exp_ge_add_one_self  now requires no hypotheses
  1661   real_of_int_add      reversed direction of equality (use [symmetric])
  1662   real_of_int_minus    reversed direction of equality (use [symmetric])
  1663   real_of_int_diff     reversed direction of equality (use [symmetric])
  1664   real_of_int_mult     reversed direction of equality (use [symmetric])
  1665 
  1666 * Theory RComplete: expanded support for floor and ceiling functions.
  1667 
  1668 * Theory Ln is new, with properties of the natural logarithm
  1669 
  1670 * Hyperreal: There is a new type constructor "star" for making
  1671 nonstandard types.  The old type names are now type synonyms:
  1672 
  1673   hypreal = real star
  1674   hypnat = nat star
  1675   hcomplex = complex star
  1676 
  1677 * Hyperreal: Many groups of similarly-defined constants have been
  1678 replaced by polymorphic versions (INCOMPATIBILITY):
  1679 
  1680   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1681 
  1682   starset      <-- starsetNat, starsetC
  1683   *s*          <-- *sNat*, *sc*
  1684   starset_n    <-- starsetNat_n, starsetC_n
  1685   *sn*         <-- *sNatn*, *scn*
  1686   InternalSets <-- InternalNatSets, InternalCSets
  1687 
  1688   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1689   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1690   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1691   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1692   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1693 
  1694 * Hyperreal: Many type-specific theorems have been removed in favor of
  1695 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1696 
  1697   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1698   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1699   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1700   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1701   right_minus <-- hypreal_add_minus
  1702   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1703   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1704   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1705   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1706   mult_1_right <-- hcomplex_mult_one_right
  1707   mult_zero_left <-- hcomplex_mult_zero_left
  1708   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1709   right_distrib <-- hypnat_add_mult_distrib2
  1710   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1711   right_inverse <-- hypreal_mult_inverse
  1712   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1713   order_refl <-- {hypreal,hypnat}_le_refl
  1714   order_trans <-- {hypreal,hypnat}_le_trans
  1715   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1716   order_less_le <-- {hypreal,hypnat}_less_le
  1717   linorder_linear <-- {hypreal,hypnat}_le_linear
  1718   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1719   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1720   add_nonneg_nonneg <-- hypreal_le_add_order
  1721 
  1722 * Hyperreal: Separate theorems having to do with type-specific
  1723 versions of constants have been merged into theorems that apply to the
  1724 new polymorphic constants (INCOMPATIBILITY):
  1725 
  1726   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1727   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1728   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1729   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1730   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1731   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1732   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1733   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1734   STAR_diff <-- {STAR,STARC}_diff
  1735   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1736     STARC_hcomplex_of_complex}_image_subset
  1737   starset_n_Un <-- starset{Nat,C}_n_Un
  1738   starset_n_Int <-- starset{Nat,C}_n_Int
  1739   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1740   starset_n_diff <-- starset{Nat,C}_n_diff
  1741   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1742   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1743   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1744   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1745   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1746   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1747   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1748   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1749   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1750   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1751   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1752   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1753   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1754   starfun_diff <-- starfun{C,RC,CR}_diff
  1755   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1756   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1757   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1758   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1759   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1760   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1761   starfun_Id <-- starfunC_Id
  1762   starfun_approx <-- starfun{Nat,CR}_approx
  1763   starfun_capprox <-- starfun{C,RC}_capprox
  1764   starfun_abs <-- starfunNat_rabs
  1765   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1766   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1767   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1768   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1769   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1770   starfun_add_approx <-- starfunCR_add_approx
  1771   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1772   starfun_divide <-- starfun{C,CR,RC}_divide
  1773   starfun_n <-- starfun{Nat,C}_n
  1774   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1775   starfun_n_add <-- starfun{Nat,C}_n_add
  1776   starfun_n_add_minus <-- starfunNat_n_add_minus
  1777   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1778   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1779   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1780 
  1781   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1782   star_n_minus <-- {hypreal,hcomplex}_minus
  1783   star_n_diff <-- {hypreal,hcomplex}_diff
  1784   star_n_mult <-- {hypreal,hcomplex}_mult
  1785   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1786   star_n_le <-- {hypreal,hypnat}_le
  1787   star_n_less <-- {hypreal,hypnat}_less
  1788   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1789   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1790   star_n_abs <-- hypreal_hrabs
  1791   star_n_divide <-- hcomplex_divide
  1792 
  1793   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1794   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1795   star_of_diff <-- hypreal_of_real_diff
  1796   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1797   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1798   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1799   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1800   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1801   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1802   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1803   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1804   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1805   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1806   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1807   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1808   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1809   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1810   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1811   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1812   star_of_power <-- hypreal_of_real_power
  1813   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1814 
  1815 * Hyperreal: new method "transfer" that implements the transfer
  1816 principle of nonstandard analysis. With a subgoal that mentions
  1817 nonstandard types like "'a star", the command "apply transfer"
  1818 replaces it with an equivalent one that mentions only standard types.
  1819 To be successful, all free variables must have standard types; non-
  1820 standard variables must have explicit universal quantifiers.
  1821 
  1822 * Hyperreal: A theory of Taylor series.
  1823 
  1824 
  1825 *** HOLCF ***
  1826 
  1827 * Discontinued special version of 'constdefs' (which used to support
  1828 continuous functions) in favor of the general Pure one with full
  1829 type-inference.
  1830 
  1831 * New simplification procedure for solving continuity conditions; it
  1832 is much faster on terms with many nested lambda abstractions (cubic
  1833 instead of exponential time).
  1834 
  1835 * New syntax for domain package: selector names are now optional.
  1836 Parentheses should be omitted unless argument is lazy, for example:
  1837 
  1838   domain 'a stream = cons "'a" (lazy "'a stream")
  1839 
  1840 * New command 'fixrec' for defining recursive functions with pattern
  1841 matching; defining multiple functions with mutual recursion is also
  1842 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1843 sinr, or any data constructor defined by the domain package. The given
  1844 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1845 syntax and examples.
  1846 
  1847 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1848 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1849 but the proof obligation additionally includes an admissibility
  1850 requirement. The packages generate instances of class cpo or pcpo,
  1851 with continuity and strictness theorems for Rep and Abs.
  1852 
  1853 * HOLCF: Many theorems have been renamed according to a more standard naming
  1854 scheme (INCOMPATIBILITY):
  1855 
  1856   foo_inject:  "foo$x = foo$y ==> x = y"
  1857   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1858   foo_less:    "(foo$x << foo$y) = (x << y)"
  1859   foo_strict:  "foo$UU = UU"
  1860   foo_defined: "... ==> foo$x ~= UU"
  1861   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1862 
  1863 
  1864 *** ZF ***
  1865 
  1866 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1867 including the First Isomorphism Theorem (on quotienting by the kernel
  1868 of a homomorphism).
  1869 
  1870 * ZF/Simplifier: install second copy of type solver that actually
  1871 makes use of TC rules declared to Isar proof contexts (or locales);
  1872 the old version is still required for ML proof scripts.
  1873 
  1874 
  1875 *** Cube ***
  1876 
  1877 * Converted to Isar theory format; use locales instead of axiomatic
  1878 theories.
  1879 
  1880 
  1881 *** ML ***
  1882 
  1883 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1884 for ||>, ||>>, |>>,
  1885 
  1886 * Pure/library.ML no longer defines its own option datatype, but uses
  1887 that of the SML basis, which has constructors NONE and SOME instead of
  1888 None and Some, as well as exception Option.Option instead of OPTION.
  1889 The functions the, if_none, is_some, is_none have been adapted
  1890 accordingly, while Option.map replaces apsome.
  1891 
  1892 * Pure/library.ML: the exception LIST has been given up in favour of
  1893 the standard exceptions Empty and Subscript, as well as
  1894 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1895 superceded by the standard hd and tl functions etc.
  1896 
  1897 A number of basic list functions are no longer exported to the ML
  1898 toplevel, as they are variants of predefined functions.  The following
  1899 suggests how one can translate existing code:
  1900 
  1901     rev_append xs ys = List.revAppend (xs, ys)
  1902     nth_elem (i, xs) = List.nth (xs, i)
  1903     last_elem xs = List.last xs
  1904     flat xss = List.concat xss
  1905     seq fs = List.app fs
  1906     partition P xs = List.partition P xs
  1907     mapfilter f xs = List.mapPartial f xs
  1908 
  1909 * Pure/library.ML: several combinators for linear functional
  1910 transformations, notably reverse application and composition:
  1911 
  1912   x |> f                f #> g
  1913   (x, y) |-> f          f #-> g
  1914 
  1915 * Pure/library.ML: introduced/changed precedence of infix operators:
  1916 
  1917   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1918   infix 2 ?;
  1919   infix 3 o oo ooo oooo;
  1920   infix 4 ~~ upto downto;
  1921 
  1922 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1923 infix operators.
  1924 
  1925 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1926 fold_map support linear functional transformations and nesting.  For
  1927 example:
  1928 
  1929   fold f [x1, ..., xN] y =
  1930     y |> f x1 |> ... |> f xN
  1931 
  1932   (fold o fold) f [xs1, ..., xsN] y =
  1933     y |> fold f xs1 |> ... |> fold f xsN
  1934 
  1935   fold f [x1, ..., xN] =
  1936     f x1 #> ... #> f xN
  1937 
  1938   (fold o fold) f [xs1, ..., xsN] =
  1939     fold f xs1 #> ... #> fold f xsN
  1940 
  1941 * Pure/library.ML: the following selectors on type 'a option are
  1942 available:
  1943 
  1944   the:               'a option -> 'a  (*partial*)
  1945   these:             'a option -> 'a  where 'a = 'b list
  1946   the_default: 'a -> 'a option -> 'a
  1947   the_list:          'a option -> 'a list
  1948 
  1949 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1950 basic operations for association lists, following natural argument
  1951 order; moreover the explicit equality predicate passed here avoids
  1952 potentially expensive polymorphic runtime equality checks.
  1953 The old functions may be expressed as follows:
  1954 
  1955   assoc = uncurry (AList.lookup (op =))
  1956   assocs = these oo AList.lookup (op =)
  1957   overwrite = uncurry (AList.update (op =)) o swap
  1958 
  1959 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1960 
  1961   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1962   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1963 
  1964 replacing make_keylist and keyfilter (occassionally used)
  1965 Naive rewrites:
  1966 
  1967   make_keylist = AList.make
  1968   keyfilter = AList.find (op =)
  1969 
  1970 * eq_fst and eq_snd now take explicit equality parameter, thus
  1971   avoiding eqtypes. Naive rewrites:
  1972 
  1973     eq_fst = eq_fst (op =)
  1974     eq_snd = eq_snd (op =)
  1975 
  1976 * Removed deprecated apl and apr (rarely used).
  1977   Naive rewrites:
  1978 
  1979     apl (n, op) =>>= curry op n
  1980     apr (op, m) =>>= fn n => op (n, m)
  1981 
  1982 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1983 provides a reasonably efficient light-weight implementation of sets as
  1984 lists.
  1985 
  1986 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1987 few new operations; existing lookup and update are now curried to
  1988 follow natural argument order (for use with fold etc.);
  1989 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1990 
  1991 * Pure/General: output via the Isabelle channels of
  1992 writeln/warning/error etc. is now passed through Output.output, with a
  1993 hook for arbitrary transformations depending on the print_mode
  1994 (cf. Output.add_mode -- the first active mode that provides a output
  1995 function wins).  Already formatted output may be embedded into further
  1996 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1997 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1998 accommodate easy composition of diagnostic messages etc.  Programmers
  1999 rarely need to care about Output.output or Output.raw at all, with
  2000 some notable exceptions: Output.output is required when bypassing the
  2001 standard channels (writeln etc.), or in token translations to produce
  2002 properly formatted results; Output.raw is required when capturing
  2003 already output material that will eventually be presented to the user
  2004 a second time.  For the default print mode, both Output.output and
  2005 Output.raw have no effect.
  2006 
  2007 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2008 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2009 cumulative results are displayed at the end of a batch session.
  2010 
  2011 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2012 replaced by File.platform_path and File.shell_path (with appropriate
  2013 hooks).  This provides a clean interface for unusual systems where the
  2014 internal and external process view of file names are different.
  2015 
  2016 * Pure: more efficient orders for basic syntactic entities: added
  2017 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2018 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2019 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2020 orders now -- potential INCOMPATIBILITY for code that depends on a
  2021 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2022 Library.sort_strings on result).
  2023 
  2024 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2025 fold_types traverse types/terms from left to right, observing natural
  2026 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2027 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2028 
  2029 * Pure: name spaces have been refined, with significant changes of the
  2030 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2031 to extern(_table).  The plain name entry path is superceded by a
  2032 general 'naming' context, which also includes the 'policy' to produce
  2033 a fully qualified name and external accesses of a fully qualified
  2034 name; NameSpace.extend is superceded by context dependent
  2035 Sign.declare_name.  Several theory and proof context operations modify
  2036 the naming context.  Especially note Theory.restore_naming and
  2037 ProofContext.restore_naming to get back to a sane state; note that
  2038 Theory.add_path is no longer sufficient to recover from
  2039 Theory.absolute_path in particular.
  2040 
  2041 * Pure: new flags short_names (default false) and unique_names
  2042 (default true) for controlling output of qualified names.  If
  2043 short_names is set, names are printed unqualified.  If unique_names is
  2044 reset, the name prefix is reduced to the minimum required to achieve
  2045 the original result when interning again, even if there is an overlap
  2046 with earlier declarations.
  2047 
  2048 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2049 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2050 (useful for printing error messages).  INCOMPATIBILITY.
  2051 
  2052 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2053 Theory.theory are now identified, referring to the universal
  2054 Context.theory (see Pure/context.ML).  Actual signature and theory
  2055 content is managed as theory data.  The old code and interfaces were
  2056 spread over many files and structures; the new arrangement introduces
  2057 considerable INCOMPATIBILITY to gain more clarity:
  2058 
  2059   Context -- theory management operations (name, identity, inclusion,
  2060     parents, ancestors, merge, etc.), plus generic theory data;
  2061 
  2062   Sign -- logical signature and syntax operations (declaring consts,
  2063     types, etc.), plus certify/read for common entities;
  2064 
  2065   Theory -- logical theory operations (stating axioms, definitions,
  2066     oracles), plus a copy of logical signature operations (consts,
  2067     types, etc.); also a few basic management operations (Theory.copy,
  2068     Theory.merge, etc.)
  2069 
  2070 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2071 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2072 for convenience -- they merely return the theory.
  2073 
  2074 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2075 
  2076 * Pure: the Isar proof context type is already defined early in Pure
  2077 as Context.proof (note that ProofContext.context and Proof.context are
  2078 aliases, where the latter is the preferred name).  This enables other
  2079 Isabelle components to refer to that type even before Isar is present.
  2080 
  2081 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2082 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2083 any of these kinds.  For example, Sign.intern typeK is now
  2084 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2085 Theory.hide_types.  Also note that former
  2086 Theory.hide_classes/types/consts are now
  2087 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2088 internalize their arguments!  INCOMPATIBILITY.
  2089 
  2090 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2091 datatype thmref (with constructors Name and NameSelection) instead of
  2092 plain string -- INCOMPATIBILITY;
  2093 
  2094 * Pure: cases produced by proof methods specify options, where NONE
  2095 means to remove case bindings -- INCOMPATIBILITY in
  2096 (RAW_)METHOD_CASES.
  2097 
  2098 * Pure: the following operations retrieve axioms or theorems from a
  2099 theory node or theory hierarchy, respectively:
  2100 
  2101   Theory.axioms_of: theory -> (string * term) list
  2102   Theory.all_axioms_of: theory -> (string * term) list
  2103   PureThy.thms_of: theory -> (string * thm) list
  2104   PureThy.all_thms_of: theory -> (string * thm) list
  2105 
  2106 * Pure: print_tac now outputs the goal through the trace channel.
  2107 
  2108 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2109 Reference Toplevel.debug (default false) controls detailed printing
  2110 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2111 controls execution profiling -- set to 1 for time and 2 for space
  2112 (both increase the runtime).
  2113 
  2114 * Isar session: The initial use of ROOT.ML is now always timed,
  2115 i.e. the log will show the actual process times, in contrast to the
  2116 elapsed wall-clock time that the outer shell wrapper produces.
  2117 
  2118 * Simplifier: improved handling of bound variables (nameless
  2119 representation, avoid allocating new strings).  Simprocs that invoke
  2120 the Simplifier recursively should use Simplifier.inherit_bounds to
  2121 avoid local name clashes.  Failure to do so produces warnings
  2122 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2123 for further details.
  2124 
  2125 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2126 bindings for all theorems stored within a given theory; this may help
  2127 in porting non-Isar theories to Isar ones, while keeping ML proof
  2128 scripts for the time being.
  2129 
  2130 * ML operator HTML.with_charset specifies the charset begin used for
  2131 generated HTML files.  For example:
  2132 
  2133   HTML.with_charset "utf-8" use_thy "Hebrew";
  2134   HTML.with_charset "utf-8" use_thy "Chinese";
  2135 
  2136 
  2137 *** System ***
  2138 
  2139 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2140 isabelle, isatool etc.).
  2141 
  2142 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2143 isatool doc, isatool mkdir, display_drafts etc.).
  2144 
  2145 * isatool usedir: option -f allows specification of the ML file to be
  2146 used by Isabelle; default is ROOT.ML.
  2147 
  2148 * New isatool version outputs the version identifier of the Isabelle
  2149 distribution being used.
  2150 
  2151 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2152 (containing Boolean satisfiability problems) into Isabelle/HOL
  2153 theories.
  2154 
  2155 
  2156 
  2157 New in Isabelle2004 (April 2004)
  2158 --------------------------------
  2159 
  2160 *** General ***
  2161 
  2162 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2163   Replaces linorder.ML.
  2164 
  2165 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2166   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2167   (\<a>...\<z>), are now considered normal letters, and can therefore
  2168   be used anywhere where an ASCII letter (a...zA...Z) has until
  2169   now. COMPATIBILITY: This obviously changes the parsing of some
  2170   terms, especially where a symbol has been used as a binder, say
  2171   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2172   as an identifier.  Fix it by inserting a space around former
  2173   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2174   existing theory and ML files.
  2175 
  2176 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2177 
  2178 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2179   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2180   a normal (but invisible) letter. For multiple letter subscripts repeat
  2181   \<^isub> like this: x\<^isub>1\<^isub>2.
  2182 
  2183 * Pure: There are now sub-/superscripts that can span more than one
  2184   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2185   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2186   superscript. The new control characters are not identifier parts.
  2187 
  2188 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2189   content of "..." to the latex file instead of \isacntrl... . The "..."
  2190   may consist of any printable characters excluding the end bracket >.
  2191 
  2192 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2193   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2194   declare constants "final", which prevents their being given a definition
  2195   later.  It is useful for constants whose behaviour is fixed axiomatically
  2196   rather than definitionally, such as the meta-logic connectives.
  2197 
  2198 * Pure: 'instance' now handles general arities with general sorts
  2199   (i.e. intersections of classes),
  2200 
  2201 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2202   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2203   It can be changed to alter the colors/layout of generated pages.
  2204 
  2205 
  2206 *** Isar ***
  2207 
  2208 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2209   cut_tac, subgoal_tac and thin_tac:
  2210   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2211     locales are no longer forced to write Isar proof scripts.
  2212     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2213     emulations.
  2214   - INCOMPATIBILITY: names of variables to be instantiated may no
  2215     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2216     This is consistent with the instantiation attribute "where".
  2217 
  2218 * Attributes "where" and "of":
  2219   - Now take type variables of instantiated theorem into account when reading
  2220     the instantiation string.  This fixes a bug that caused instantiated
  2221     theorems to have too special types in some circumstances.
  2222   - "where" permits explicit instantiations of type variables.
  2223 
  2224 * Calculation commands "moreover" and "also" no longer interfere with
  2225   current facts ("this"), admitting arbitrary combinations with "then"
  2226   and derived forms.
  2227 
  2228 * Locales:
  2229   - Goal statements involving the context element "includes" no longer
  2230     generate theorems with internal delta predicates (those ending on
  2231     "_axioms") in the premise.
  2232     Resolve particular premise with <locale>.intro to obtain old form.
  2233   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2234     specification and "includes" elements in goal statement.
  2235   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2236     [intro?] and [elim?] (respectively) by default.
  2237   - Experimental command for instantiation of locales in proof contexts:
  2238         instantiate <label>[<attrs>]: <loc>
  2239     Instantiates locale <loc> and adds all its theorems to the current context
  2240     taking into account their attributes.  Label and attrs are optional
  2241     modifiers, like in theorem declarations.  If present, names of
  2242     instantiated theorems are qualified with <label>, and the attributes
  2243     <attrs> are applied after any attributes these theorems might have already.
  2244       If the locale has assumptions, a chained fact of the form
  2245     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2246     are derived.  The command does not support old-style locales declared
  2247     with "locale (open)".
  2248       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2249 
  2250 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2251   (Isar) contexts.
  2252 
  2253 
  2254 *** HOL ***
  2255 
  2256 * Proof import: new image HOL4 contains the imported library from
  2257   the HOL4 system with about 2500 theorems. It is imported by
  2258   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2259   can be used like any other Isabelle image.  See
  2260   HOL/Import/HOL/README for more information.
  2261 
  2262 * Simplifier:
  2263   - Much improved handling of linear and partial orders.
  2264     Reasoners for linear and partial orders are set up for type classes
  2265     "linorder" and "order" respectively, and are added to the default simpset
  2266     as solvers.  This means that the simplifier can build transitivity chains
  2267     to solve goals from the assumptions.
  2268   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2269     of blast or auto after simplification become unnecessary because the goal
  2270     is solved by simplification already.
  2271 
  2272 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2273     all proved in axiomatic type classes for semirings, rings and fields.
  2274 
  2275 * Numerics:
  2276   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2277     now formalized using the Ring_and_Field theory mentioned above.
  2278   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2279     than before, because now they are set up once in a generic manner.
  2280   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2281     Look for the general versions in Ring_and_Field (and Power if they concern
  2282     exponentiation).
  2283 
  2284 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2285 
  2286 * Records:
  2287   - Record types are now by default printed with their type abbreviation
  2288     instead of the list of all field types. This can be configured via
  2289     the reference "print_record_type_abbr".
  2290   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2291     (not enabled by default).
  2292   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2293     EX x. x = sel r to True (not enabled by default).
  2294   - Tactic "record_split_simp_tac" to split and simplify records added.
  2295 
  2296 * 'specification' command added, allowing for definition by
  2297   specification.  There is also an 'ax_specification' command that
  2298   introduces the new constants axiomatically.
  2299 
  2300 * arith(_tac) is now able to generate counterexamples for reals as well.
  2301 
  2302 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2303 
  2304 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2305   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2306 
  2307 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2308   matrix theory to linear programming.
  2309 
  2310 * Unions and Intersections:
  2311   The latex output syntax of UN and INT has been changed
  2312   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2313   i.e. the index formulae has become a subscript.
  2314   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2315 
  2316 * Unions and Intersections over Intervals:
  2317   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2318   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2319   like in normal math, and corresponding versions for < and for intersection.
  2320 
  2321 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2322   lexicographic dictonary ordering has been added as "lexord".
  2323 
  2324 * ML: the legacy theory structures Int and List have been removed. They had
  2325   conflicted with ML Basis Library structures having the same names.
  2326 
  2327 * 'refute' command added to search for (finite) countermodels.  Only works
  2328   for a fragment of HOL.  The installation of an external SAT solver is
  2329   highly recommended.  See "HOL/Refute.thy" for details.
  2330 
  2331 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2332   formulae under an assignment of free variables to random values.
  2333   In contrast to 'refute', it can deal with inductive datatypes,
  2334   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2335   for examples.
  2336 
  2337 
  2338 *** HOLCF ***
  2339 
  2340 * Streams now come with concatenation and are part of the HOLCF image
  2341 
  2342 
  2343 
  2344 New in Isabelle2003 (May 2003)
  2345 ------------------------------
  2346 
  2347 *** General ***
  2348 
  2349 * Provers/simplifier:
  2350 
  2351   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2352     Assumptions are now subject to complete mutual simplification,
  2353     not just from left to right. The simplifier now preserves
  2354     the order of assumptions.
  2355 
  2356     Potential INCOMPATIBILITY:
  2357 
  2358     -- simp sometimes diverges where the old version did
  2359        not, e.g. invoking simp on the goal
  2360 
  2361         [| P (f x); y = x; f x = f y |] ==> Q
  2362 
  2363        now gives rise to the infinite reduction sequence
  2364 
  2365         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2366 
  2367        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2368        kind of problem.
  2369 
  2370     -- Tactics combining classical reasoner and simplification (such as auto)
  2371        are also affected by this change, because many of them rely on
  2372        simp. They may sometimes diverge as well or yield a different numbers
  2373        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2374        in case of problems. Sometimes subsequent calls to the classical
  2375        reasoner will fail because a preceeding call to the simplifier too
  2376        eagerly simplified the goal, e.g. deleted redundant premises.
  2377 
  2378   - The simplifier trace now shows the names of the applied rewrite rules
  2379 
  2380   - You can limit the number of recursive invocations of the simplifier
  2381     during conditional rewriting (where the simplifie tries to solve the
  2382     conditions before applying the rewrite rule):
  2383     ML "simp_depth_limit := n"
  2384     where n is an integer. Thus you can force termination where previously
  2385     the simplifier would diverge.
  2386 
  2387   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2388 
  2389   - No longer aborts on failed congruence proof.  Instead, the
  2390     congruence is ignored.
  2391 
  2392 * Pure: New generic framework for extracting programs from constructive
  2393   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2394   as HOL/Extraction for some case studies.
  2395 
  2396 * Pure: The main goal of the proof state is no longer shown by default, only
  2397 the subgoals. This behaviour is controlled by a new flag.
  2398    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2399 (ML: Proof.show_main_goal).
  2400 
  2401 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2402 rules whose conclusion matches subgoal 1:
  2403       PG menu: Isabelle/Isar -> Show me -> matching rules
  2404 The rules are ordered by how closely they match the subgoal.
  2405 In particular, rules that solve a subgoal outright are displayed first
  2406 (or rather last, the way they are printed).
  2407 (ML: ProofGeneral.print_intros())
  2408 
  2409 * Pure: New flag trace_unify_fail causes unification to print
  2410 diagnostic information (PG: in trace buffer) when it fails. This is
  2411 useful for figuring out why single step proofs like rule, erule or
  2412 assumption failed.
  2413 
  2414 * Pure: Locale specifications now produce predicate definitions
  2415 according to the body of text (covering assumptions modulo local
  2416 definitions); predicate "loc_axioms" covers newly introduced text,
  2417 while "loc" is cumulative wrt. all included locale expressions; the
  2418 latter view is presented only on export into the global theory
  2419 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2420 on the old view without predicates;
  2421 
  2422 * Pure: predefined locales "var" and "struct" are useful for sharing
  2423 parameters (as in CASL, for example); just specify something like
  2424 ``var x + var y + struct M'' as import;
  2425 
  2426 * Pure: improved thms_containing: proper indexing of facts instead of
  2427 raw theorems; check validity of results wrt. current name space;
  2428 include local facts of proof configuration (also covers active
  2429 locales), cover fixed variables in index; may use "_" in term
  2430 specification; an optional limit for the number of printed facts may
  2431 be given (the default is 40);
  2432 
  2433 * Pure: disallow duplicate fact bindings within new-style theory files
  2434 (batch-mode only);
  2435 
  2436 * Provers: improved induct method: assumptions introduced by case
  2437 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2438 the goal statement); "foo" still refers to all facts collectively;
  2439 
  2440 * Provers: the function blast.overloaded has been removed: all constants
  2441 are regarded as potentially overloaded, which improves robustness in exchange
  2442 for slight decrease in efficiency;
  2443 
  2444 * Provers/linorder: New generic prover for transitivity reasoning over
  2445 linear orders.  Note: this prover is not efficient!
  2446 
  2447 * Isar: preview of problems to finish 'show' now produce an error
  2448 rather than just a warning (in interactive mode);
  2449 
  2450 
  2451 *** HOL ***
  2452 
  2453 * arith(_tac)
  2454 
  2455  - Produces a counter example if it cannot prove a goal.
  2456    Note that the counter example may be spurious if the goal is not a formula
  2457    of quantifier-free linear arithmetic.
  2458    In ProofGeneral the counter example appears in the trace buffer.
  2459 
  2460  - Knows about div k and mod k where k is a numeral of type nat or int.
  2461 
  2462  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2463    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2464    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2465 
  2466 * simp's arithmetic capabilities have been enhanced a bit: it now
  2467 takes ~= in premises into account (by performing a case split);
  2468 
  2469 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2470 are distributed over a sum of terms;
  2471 
  2472 * New tactic "trans_tac" and method "trans" instantiate
  2473 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2474 "<=", "<" and "=").
  2475 
  2476 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2477 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2478 
  2479 * 'typedef' command has new option "open" to suppress the set
  2480 definition;
  2481 
  2482 * functions Min and Max on finite sets have been introduced (theory
  2483 Finite_Set);
  2484 
  2485 * attribute [symmetric] now works for relations as well; it turns
  2486 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2487 
  2488 * induct over a !!-quantified statement (say !!x1..xn):
  2489   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2490 
  2491 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2492 %x. None. Warning: empty_def now refers to the previously hidden definition
  2493 of the empty set.
  2494 
  2495 * Algebra: formalization of classical algebra.  Intended as base for
  2496 any algebraic development in Isabelle.  Currently covers group theory
  2497 (up to Sylow's theorem) and ring theory (Universal Property of
  2498 Univariate Polynomials).  Contributions welcome;
  2499 
  2500 * GroupTheory: deleted, since its material has been moved to Algebra;
  2501 
  2502 * Complex: new directory of the complex numbers with numeric constants,
  2503 nonstandard complex numbers, and some complex analysis, standard and
  2504 nonstandard (Jacques Fleuriot);
  2505 
  2506 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2507 
  2508 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2509 Fleuriot);
  2510 
  2511 * Real/HahnBanach: updated and adapted to locales;
  2512 
  2513 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2514 Gray and Kramer);
  2515 
  2516 * UNITY: added the Meier-Sanders theory of progress sets;
  2517 
  2518 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2519 as abstract algorithms, instantiated to the JVM;
  2520 
  2521 * Bali: Java source language formalization. Type system, operational
  2522 semantics, axiomatic semantics. Supported language features:
  2523 classes, interfaces, objects,virtual methods, static methods,
  2524 static/instance fields, arrays, access modifiers, definite
  2525 assignment, exceptions.
  2526 
  2527 
  2528 *** ZF ***
  2529 
  2530 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2531 universe, etc.);
  2532 
  2533 * Main ZF: virtually all theories converted to new-style format;
  2534 
  2535 
  2536 *** ML ***
  2537 
  2538 * Pure: Tactic.prove provides sane interface for internal proofs;
  2539 omits the infamous "standard" operation, so this is more appropriate
  2540 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2541 
  2542 * Pure: improved error reporting of simprocs;
  2543 
  2544 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2545 up simprocs;
  2546 
  2547 
  2548 *** Document preparation ***
  2549 
  2550 * uses \par instead of \\ for line breaks in theory text. This may
  2551 shift some page breaks in large documents. To get the old behaviour
  2552 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2553 
  2554 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2555 other packages
  2556 
  2557 * \<euro> now needs package babel/greek instead of marvosym (which
  2558 broke \Rightarrow)
  2559 
  2560 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2561 textcomp package)
  2562 
  2563 
  2564 
  2565 New in Isabelle2002 (March 2002)
  2566 --------------------------------
  2567 
  2568 *** Document preparation ***
  2569 
  2570 * greatly simplified document preparation setup, including more
  2571 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2572 instructive isatool mkdir; users should basically be able to get
  2573 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2574 users may run a separate document processing stage manually like this:
  2575 "isatool usedir -D output HOL Test && isatool document Test/output";
  2576 
  2577 * theory dependency graph may now be incorporated into documents;
  2578 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2579 with \includegraphics of LaTeX;
  2580 
  2581 * proper spacing of consecutive markup elements, especially text
  2582 blocks after section headings;
  2583 
  2584 * support bold style (for single symbols only), input syntax is like
  2585 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2586 
  2587 * \<bullet> is now output as bold \cdot by default, which looks much
  2588 better in printed text;
  2589 
  2590 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2591 note that these symbols are currently unavailable in Proof General /
  2592 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2593 
  2594 * isatool latex no longer depends on changed TEXINPUTS, instead
  2595 isatool document copies the Isabelle style files to the target
  2596 location;
  2597 
  2598 
  2599 *** Isar ***
  2600 
  2601 * Pure/Provers: improved proof by cases and induction;
  2602   - 'case' command admits impromptu naming of parameters (such as
  2603     "case (Suc n)");
  2604   - 'induct' method divinates rule instantiation from the inductive
  2605     claim; no longer requires excessive ?P bindings for proper
  2606     instantiation of cases;
  2607   - 'induct' method properly enumerates all possibilities of set/type
  2608     rules; as a consequence facts may be also passed through *type*
  2609     rules without further ado;
  2610   - 'induct' method now derives symbolic cases from the *rulified*
  2611     rule (before it used to rulify cases stemming from the internal
  2612     atomized version); this means that the context of a non-atomic
  2613     statement becomes is included in the hypothesis, avoiding the
  2614     slightly cumbersome show "PROP ?case" form;
  2615   - 'induct' may now use elim-style induction rules without chaining
  2616     facts, using ``missing'' premises from the goal state; this allows
  2617     rules stemming from inductive sets to be applied in unstructured
  2618     scripts, while still benefitting from proper handling of non-atomic
  2619     statements; NB: major inductive premises need to be put first, all
  2620     the rest of the goal is passed through the induction;
  2621   - 'induct' proper support for mutual induction involving non-atomic
  2622     rule statements (uses the new concept of simultaneous goals, see
  2623     below);
  2624   - append all possible rule selections, but only use the first
  2625     success (no backtracking);
  2626   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2627   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2628   - added 'print_induct_rules' (covered by help item in recent Proof
  2629     General versions);
  2630   - moved induct/cases attributes to Pure, methods to Provers;
  2631   - generic method setup instantiated for FOL and HOL;
  2632 
  2633 * Pure: support multiple simultaneous goal statements, for example
  2634 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2635 meta-level mechanism, this acts as if several individual goals had
  2636 been stated separately; in particular common proof methods need to be
  2637 repeated in order to cover all claims; note that a single elimination
  2638 step is *not* sufficient to establish the two conjunctions, so this
  2639 fails:
  2640 
  2641   assume "A & B" then have A and B ..   (*".." fails*)
  2642 
  2643 better use "obtain" in situations as above; alternative refer to
  2644 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2645 
  2646 * Pure: proper integration with ``locales''; unlike the original
  2647 version by Florian Kammller, Isar locales package high-level proof
  2648 contexts rather than raw logical ones (e.g. we admit to include
  2649 attributes everywhere); operations on locales include merge and
  2650 rename; support for implicit arguments (``structures''); simultaneous
  2651 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2652 some examples;
  2653 
  2654 * Pure: the following commands have been ``localized'', supporting a
  2655 target locale specification "(in name)": 'lemma', 'theorem',
  2656 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2657 stored both within the locale and at the theory level (exported and
  2658 qualified by the locale name);
  2659 
  2660 * Pure: theory goals may now be specified in ``long'' form, with
  2661 ad-hoc contexts consisting of arbitrary locale elements. for example
  2662 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2663 definitions may be given, too); the result is a meta-level rule with
  2664 the context elements being discharged in the obvious way;
  2665 
  2666 * Pure: new proof command 'using' allows to augment currently used
  2667 facts after a goal statement ('using' is syntactically analogous to
  2668 'apply', but acts on the goal's facts only); this allows chained facts
  2669 to be separated into parts given before and after a claim, as in
  2670 ``from a and b have C using d and e <proof>'';
  2671 
  2672 * Pure: renamed "antecedent" case to "rule_context";
  2673 
  2674 * Pure: new 'judgment' command records explicit information about the
  2675 object-logic embedding (used by several tools internally); no longer
  2676 use hard-wired "Trueprop";
  2677 
  2678 * Pure: added 'corollary' command;
  2679 
  2680 * Pure: fixed 'token_translation' command;
  2681 
  2682 * Pure: removed obsolete 'exported' attribute;
  2683 
  2684 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2685 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2686 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2687 
  2688 * Pure: method 'atomize' presents local goal premises as object-level
  2689 statements (atomic meta-level propositions); setup controlled via
  2690 rewrite rules declarations of 'atomize' attribute; example
  2691 application: 'induct' method with proper rule statements in improper
  2692 proof *scripts*;
  2693 
  2694 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2695 now consider the syntactic context of assumptions, giving a better
  2696 chance to get type-inference of the arguments right (this is
  2697 especially important for locales);
  2698 
  2699 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2700 mode;
  2701 
  2702 * Pure/obtain: the formal conclusion "thesis", being marked as
  2703 ``internal'', may no longer be reference directly in the text;
  2704 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2705 situations;
  2706 
  2707 * Pure: generic 'sym' attribute which declares a rule both as pure
  2708 'elim?' and for the 'symmetric' operation;
  2709 
  2710 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2711 text; the fixed correlation with particular command syntax has been
  2712 discontinued;
  2713 
  2714 * Pure: new method 'rules' is particularly well-suited for proof
  2715 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2716 but often produces more compact proof terms with less detours;
  2717 
  2718 * Pure/Provers/classical: simplified integration with pure rule
  2719 attributes and methods; the classical "intro?/elim?/dest?"
  2720 declarations coincide with the pure ones; the "rule" method no longer
  2721 includes classically swapped intros; "intro" and "elim" methods no
  2722 longer pick rules from the context; also got rid of ML declarations
  2723 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2724 INCOMPATIBILITY;
  2725 
  2726 * Provers/classical: attribute 'swapped' produces classical inversions
  2727 of introduction rules;
  2728 
  2729 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2730 rules instead of full simplifier context; 'iff' attribute handles
  2731 conditional rules;
  2732 
  2733 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2734 
  2735 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2736 "(permissive)" option to recover old behavior;
  2737 
  2738 * HOL: 'inductive' no longer features separate (collective) attributes
  2739 for 'intros' (was found too confusing);
  2740 
  2741 * HOL: properly declared induction rules less_induct and
  2742 wf_induct_rule;
  2743 
  2744 
  2745 *** HOL ***
  2746 
  2747 * HOL: moved over to sane numeral syntax; the new policy is as
  2748 follows:
  2749 
  2750   - 0 and 1 are polymorphic constants, which are defined on any
  2751   numeric type (nat, int, real etc.);
  2752 
  2753   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2754   binary representation internally;
  2755 
  2756   - type nat has special constructor Suc, and generally prefers Suc 0
  2757   over 1::nat and Suc (Suc 0) over 2::nat;
  2758 
  2759 This change may cause significant problems of INCOMPATIBILITY; here
  2760 are some hints on converting existing sources:
  2761 
  2762   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2763   entities, so expressions involving "-" (unary or binary minus) need
  2764   to be spaced properly;
  2765 
  2766   - existing occurrences of "1" may need to be constraint "1::nat" or
  2767   even replaced by Suc 0; similar for old "2";
  2768 
  2769   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2770 
  2771   - remove all special provisions on numerals in proofs;
  2772 
  2773 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2774 representation (depends on bin_arith_simps in the default context);
  2775 
  2776 * HOL: symbolic syntax for x^2 (numeral 2);
  2777 
  2778 * HOL: the class of all HOL types is now called "type" rather than
  2779 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2780 in axclass/classes, instance/arities, and (usually rare) occurrences
  2781 in typings (of consts etc.); internally the class is called
  2782 "HOL.type", ML programs should refer to HOLogic.typeS;
  2783 
  2784 * HOL/record package improvements:
  2785   - new derived operations "fields" to build a partial record section,
  2786     "extend" to promote a fixed record to a record scheme, and
  2787     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2788     declared as simp by default;
  2789   - shared operations ("more", "fields", etc.) now need to be always
  2790     qualified) --- potential INCOMPATIBILITY;
  2791   - removed "make_scheme" operations (use "make" with "extend") --
  2792     INCOMPATIBILITY;
  2793   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2794   - provides cases/induct rules for use with corresponding Isar
  2795     methods (for concrete records, record schemes, concrete more
  2796     parts, and schematic more parts -- in that order);
  2797   - internal definitions directly based on a light-weight abstract
  2798     theory of product types over typedef rather than datatype;
  2799 
  2800 * HOL: generic code generator for generating executable ML code from
  2801 specifications; specific support for HOL constructs such as inductive
  2802 datatypes and sets, as well as recursive functions; can be invoked
  2803 via 'generate_code' theory section;
  2804 
  2805 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2806 
  2807 * HOL: consolidated and renamed several theories.  In particular:
  2808         Ord.thy has been absorbed into HOL.thy
  2809         String.thy has been absorbed into List.thy
  2810 
  2811 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2812 (beware of argument permutation!);
  2813 
  2814 * HOL: linorder_less_split superseded by linorder_cases;
  2815 
  2816 * HOL/List: "nodups" renamed to "distinct";
  2817 
  2818 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2819 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2820   - Ex_def has changed, now need to use some_eq_ex
  2821 
  2822 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2823 in this (rare) case use:
  2824 
  2825   delSWrapper "split_all_tac"
  2826   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2827 
  2828 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2829 MAY FAIL;
  2830 
  2831 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2832 Isabelle's type classes, ^ on functions and relations has too general
  2833 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2834 necessary to attach explicit type constraints;
  2835 
  2836 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2837 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2838 renamed accordingly (eg "compI" -> "rel_compI").
  2839 
  2840 * HOL: syntax translations now work properly with numerals and records
  2841 expressions;
  2842 
  2843 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2844 of "lam" -- INCOMPATIBILITY;
  2845 
  2846 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2847 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2848 renamed "Product_Type.unit";
  2849 
  2850 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2851 
  2852 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2853 the "cases" method);
  2854 
  2855 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2856 Florian Kammller);
  2857 
  2858 * HOL/IMP: updated and converted to new-style theory format; several
  2859 parts turned into readable document, with proper Isar proof texts and
  2860 some explanations (by Gerwin Klein);
  2861 
  2862 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2863 
  2864 * HOL-Hyperreal is now a logic image;
  2865 
  2866 
  2867 *** HOLCF ***
  2868 
  2869 * Isar: consts/constdefs supports mixfix syntax for continuous
  2870 operations;
  2871 
  2872 * Isar: domain package adapted to new-style theory format, e.g. see
  2873 HOLCF/ex/Dnat.thy;
  2874 
  2875 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2876 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2877 lift.induct_tac, always use UU instead of Undef;
  2878 
  2879 * HOLCF/IMP: updated and converted to new-style theory;
  2880 
  2881 
  2882 *** ZF ***
  2883 
  2884 * Isar: proper integration of logic-specific tools and packages,
  2885 including theory commands '(co)inductive', '(co)datatype',
  2886 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2887 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2888 
  2889 * theory Main no longer includes AC; for the Axiom of Choice, base
  2890 your theory on Main_ZFC;
  2891 
  2892 * the integer library now covers quotients and remainders, with many
  2893 laws relating division to addition, multiplication, etc.;
  2894 
  2895 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2896 typeless version of the formalism;
  2897 
  2898 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2899 format;
  2900 
  2901 * ZF/Induct: new directory for examples of inductive definitions,
  2902 including theory Multiset for multiset orderings; converted to
  2903 new-style theory format;
  2904 
  2905 * ZF: many new theorems about lists, ordinals, etc.;
  2906 
  2907 
  2908 *** General ***
  2909 
  2910 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2911 variable proof controls level of detail: 0 = no proofs (only oracle
  2912 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2913 also ref manual for further ML interfaces;
  2914 
  2915 * Pure/axclass: removed obsolete ML interface
  2916 goal_subclass/goal_arity;
  2917 
  2918 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2919 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2920 separate tokens, so expressions involving minus need to be spaced
  2921 properly;
  2922 
  2923 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2924 rather than "infixl" or "infixr";
  2925 
  2926 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2927 sort constraint specifications in type inference; e.g. "x::_::foo"
  2928 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2929 type variable);
  2930 
  2931 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2932 control output of nested => (types); the default behavior is
  2933 "type_brackets";
  2934 
  2935 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2936 tokens into AST constants;
  2937 
  2938 * Pure/syntax: prefer later declarations of translations and print
  2939 translation functions; potential INCOMPATIBILITY: need to reverse
  2940 multiple declarations for same syntax element constant;
  2941 
  2942 * Pure/show_hyps reset by default (in accordance to existing Isar
  2943 practice);
  2944 
  2945 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2946 addSafter;
  2947 
  2948 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2949 as well;
  2950 
  2951 * system: tested support for MacOS X; should be able to get Isabelle +
  2952 Proof General to work in a plain Terminal after installing Poly/ML
  2953 (e.g. from the Isabelle distribution area) and GNU bash alone
  2954 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2955 support requires further installations, e.g. from
  2956 http://fink.sourceforge.net/);
  2957 
  2958 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2959 
  2960 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2961 of 40 MB), cf. ML_OPTIONS;
  2962 
  2963 * system: Proof General keywords specification is now part of the
  2964 Isabelle distribution (see etc/isar-keywords.el);
  2965 
  2966 * system: support for persistent Proof General sessions (refrain from
  2967 outdating all loaded theories on startup); user may create writable
  2968 logic images like this: ``isabelle -q HOL Test'';
  2969 
  2970 * system: smart selection of Isabelle process versus Isabelle
  2971 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2972 run both "isabelle" and "Isabelle" even if file names are badly
  2973 damaged (executable inspects the case of the first letter of its own
  2974 name); added separate "isabelle-process" and "isabelle-interface";
  2975 
  2976 * system: refrain from any attempt at filtering input streams; no
  2977 longer support ``8bit'' encoding of old isabelle font, instead proper
  2978 iso-latin characters may now be used; the related isatools
  2979 "symbolinput" and "nonascii" have disappeared as well;
  2980 
  2981 * system: removed old "xterm" interface (the print modes "xterm" and
  2982 "xterm_color" are still available for direct use in a suitable
  2983 terminal);
  2984 
  2985 
  2986 
  2987 New in Isabelle99-2 (February 2001)
  2988 -----------------------------------
  2989 
  2990 *** Overview of INCOMPATIBILITIES ***
  2991 
  2992 * HOL: please note that theories in the Library and elsewhere often use the
  2993 new-style (Isar) format; to refer to their theorems in an ML script you must
  2994 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2995 
  2996 * HOL: inductive package no longer splits induction rule aggressively,
  2997 but only as far as specified by the introductions given; the old
  2998 format may be recovered via ML function complete_split_rule or attribute
  2999 'split_rule (complete)';
  3000 
  3001 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3002 gfp_Tarski to gfp_unfold;
  3003 
  3004 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3005 
  3006 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3007 relation); infix "^^" has been renamed "``"; infix "``" has been
  3008 renamed "`"; "univalent" has been renamed "single_valued";
  3009 
  3010 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3011 operation;
  3012 
  3013 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3014 
  3015 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3016 
  3017 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3018 consequence, it is no longer monotonic wrt. the local goal context
  3019 (which is now passed through the inductive cases);
  3020 
  3021 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3022 \<gg> to \<ggreater>;
  3023 
  3024 
  3025 *** Document preparation ***
  3026 
  3027 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3028 available: are "it" for near math-mode best-style output, "sl" for
  3029 slanted text style, and "tt" for plain type-writer; if no
  3030 \isabellestyle command is given, output is according to slanted
  3031 type-writer);
  3032 
  3033 * support sub/super scripts (for single symbols only), input syntax is
  3034 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3035 
  3036 * some more standard symbols; see Appendix A of the system manual for
  3037 the complete list of symbols defined in isabellesym.sty;
  3038 
  3039 * improved isabelle style files; more abstract symbol implementation
  3040 (should now use \isamath{...} and \isatext{...} in custom symbol
  3041 definitions);
  3042 
  3043 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3044 state; Note that presentation of goal states does not conform to
  3045 actual human-readable proof documents.  Please do not include goal
  3046 states into document output unless you really know what you are doing!
  3047 
  3048 * proper indentation of antiquoted output with proportional LaTeX
  3049 fonts;
  3050 
  3051 * no_document ML operator temporarily disables LaTeX document
  3052 generation;
  3053 
  3054 * isatool unsymbolize tunes sources for plain ASCII communication;
  3055 
  3056 
  3057 *** Isar ***
  3058 
  3059 * Pure: Isar now suffers initial goal statements to contain unbound
  3060 schematic variables (this does not conform to actual readable proof
  3061 documents, due to unpredictable outcome and non-compositional proof
  3062 checking); users who know what they are doing may use schematic goals
  3063 for Prolog-style synthesis of proven results;
  3064 
  3065 * Pure: assumption method (an implicit finishing) now handles actual
  3066 rules as well;
  3067 
  3068 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3069 initial goal, declare "that" only as Pure intro (only for single
  3070 steps); the "that" rule assumption may now be involved in implicit
  3071 finishing, thus ".." becomes a feasible for trivial obtains;
  3072 
  3073 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3074 instance proofs may be performed by "..";
  3075 
  3076 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3077 statements as well;
  3078 
  3079 * Pure: more robust selection of calculational rules;
  3080 
  3081 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3082 rule (as well as the assumption rule);
  3083 
  3084 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3085 lemmas, using the graph browser tool;
  3086 
  3087 * Pure: predict failure of "show" in interactive mode;
  3088 
  3089 * Pure: 'thms_containing' now takes actual terms as arguments;
  3090 
  3091 * HOL: improved method 'induct' --- now handles non-atomic goals
  3092 (potential INCOMPATIBILITY); tuned error handling;
  3093 
  3094 * HOL: cases and induct rules now provide explicit hints about the
  3095 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3096 any remaining facts are inserted into the goal verbatim;
  3097 
  3098 * HOL: local contexts (aka cases) may now contain term bindings as
  3099 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3100 the result to be shown in each case;
  3101 
  3102 * HOL: added 'recdef_tc' command;
  3103 
  3104 * isatool convert assists in eliminating legacy ML scripts;
  3105 
  3106 
  3107 *** HOL ***
  3108 
  3109 * HOL/Library: a collection of generic theories to be used together
  3110 with main HOL; the theory loader path already includes this directory
  3111 by default; the following existing theories have been moved here:
  3112 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3113 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3114 
  3115 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3116 modelling and verification task performed in Isabelle/HOL +
  3117 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3118 
  3119 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3120 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3121 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3122 'domain', this makes the theory consistent with mathematical
  3123 literature;
  3124 
  3125 * HOL basics: added overloaded operations "inverse" and "divide"
  3126 (infix "/"), syntax for generic "abs" operation, generic summation
  3127 operator \<Sum>;
  3128 
  3129 * HOL/typedef: simplified package, provide more useful rules (see also
  3130 HOL/subset.thy);
  3131 
  3132 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3133 now expressed as a proper nested rule (old-style tactic scripts may
  3134 require atomize_strip_tac to cope with non-atomic premises);
  3135 
  3136 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3137 to "split_conv" (old name still available for compatibility);
  3138 
  3139 * HOL: improved concrete syntax for strings (e.g. allows translation
  3140 rules with string literals);
  3141 
  3142 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3143  and Fleuriot's mechanization of analysis, including the transcendental
  3144  functions for the reals;
  3145 
  3146 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3147 
  3148 
  3149 *** CTT ***
  3150 
  3151 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3152 "lam" is displayed as TWO lambda-symbols
  3153 
  3154 * CTT: theory Main now available, containing everything (that is, Bool
  3155 and Arith);
  3156 
  3157 
  3158 *** General ***
  3159 
  3160 * Pure: the Simplifier has been implemented properly as a derived rule
  3161 outside of the actual kernel (at last!); the overall performance
  3162 penalty in practical applications is about 50%, while reliability of
  3163 the Isabelle inference kernel has been greatly improved;
  3164 
  3165 * print modes "brackets" and "no_brackets" control output of nested =>
  3166 (types) and ==> (props); the default behaviour is "brackets";
  3167 
  3168 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3169 as assumptions as well;
  3170 
  3171 * system: support Poly/ML 4.0;
  3172 
  3173 * system: isatool install handles KDE version 1 or 2;
  3174 
  3175 
  3176 
  3177 New in Isabelle99-1 (October 2000)
  3178 ----------------------------------
  3179 
  3180 *** Overview of INCOMPATIBILITIES ***
  3181 
  3182 * HOL: simplification of natural numbers is much changed; to partly
  3183 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3184 issue the following ML commands:
  3185 
  3186   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3187   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3188 
  3189 * HOL: simplification no longer dives into case-expressions; this is
  3190 controlled by "t.weak_case_cong" for each datatype t;
  3191 
  3192 * HOL: nat_less_induct renamed to less_induct;
  3193 
  3194 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3195 fixsome to patch .thy and .ML sources automatically;
  3196 
  3197   select_equality  -> some_equality
  3198   select_eq_Ex     -> some_eq_ex
  3199   selectI2EX       -> someI2_ex
  3200   selectI2         -> someI2
  3201   selectI          -> someI
  3202   select1_equality -> some1_equality
  3203   Eps_sym_eq       -> some_sym_eq_trivial
  3204   Eps_eq           -> some_eq_trivial
  3205 
  3206 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3207 
  3208 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3209 instead);
  3210 
  3211 * HOL: the recursion equations generated by 'recdef' are now called
  3212 f.simps instead of f.rules;
  3213 
  3214 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3215 
  3216 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3217 sometimes be needed;
  3218 
  3219 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3220 
  3221 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3222 
  3223 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3224 product is now "<*>" instead of "Times"; the lexicographic product is
  3225 now "<*lex*>" instead of "**";
  3226 
  3227 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3228 of main HOL, but was unused); better use HOL's datatype package;
  3229 
  3230 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3231 the old syntax may be recovered as follows:
  3232 
  3233   syntax (symbols)
  3234     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3235       (infixl "\\<oplus>" 100)
  3236 
  3237 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3238 
  3239 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3240 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3241 internally;
  3242 
  3243 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3244 changed from A/r to A//r;
  3245 
  3246 * ZF: new treatment of arithmetic (nat & int) may break some old
  3247 proofs;
  3248 
  3249 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3250 rulify -> rule_format, elimify -> elim_format, ...);
  3251 
  3252 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3253 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3254 should have to change intro!! to intro? only); replaced "delrule" by
  3255 "rule del";
  3256 
  3257 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3258 
  3259 * Provers: strengthened force_tac by using new first_best_tac;
  3260 
  3261 * LaTeX document preparation: several changes of isabelle.sty (see
  3262 lib/texinputs);
  3263 
  3264 
  3265 *** Document preparation ***
  3266 
  3267 * formal comments (text blocks etc.) in new-style theories may now
  3268 contain antiquotations of thm/prop/term/typ/text to be presented
  3269 according to latex print mode; concrete syntax is like this:
  3270 @{term[show_types] "f(x) = a + x"};
  3271 
  3272 * isatool mkdir provides easy setup of Isabelle session directories,
  3273 including proper document sources;
  3274 
  3275 * generated LaTeX sources are now deleted after successful run
  3276 (isatool document -c); may retain a copy somewhere else via -D option
  3277 of isatool usedir;
  3278 
  3279 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3280 style files, achieving self-contained LaTeX sources and simplifying
  3281 LaTeX debugging;
  3282 
  3283 * old-style theories now produce (crude) LaTeX output as well;
  3284 
  3285 * browser info session directories are now self-contained (may be put
  3286 on WWW server seperately); improved graphs of nested sessions; removed
  3287 graph for 'all sessions';
  3288 
  3289 * several improvements in isabelle style files; \isabellestyle{it}
  3290 produces fake math mode output; \isamarkupheader is now \section by
  3291 default; see lib/texinputs/isabelle.sty etc.;
  3292 
  3293 
  3294 *** Isar ***
  3295 
  3296 * Isar/Pure: local results and corresponding term bindings are now
  3297 subject to Hindley-Milner polymorphism (similar to ML); this
  3298 accommodates incremental type-inference very nicely;
  3299 
  3300 * Isar/Pure: new derived language element 'obtain' supports
  3301 generalized existence reasoning;
  3302 
  3303 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3304 support accumulation of results, without applying any rules yet;
  3305 useful to collect intermediate results without explicit name
  3306 references, and for use with transitivity rules with more than 2
  3307 premises;
  3308 
  3309 * Isar/Pure: scalable support for case-analysis type proofs: new
  3310 'case' language element refers to local contexts symbolically, as
  3311 produced by certain proof methods; internally, case names are attached
  3312 to theorems as "tags";
  3313 
  3314 * Isar/Pure: theory command 'hide' removes declarations from
  3315 class/type/const name spaces;
  3316 
  3317 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3318 indicate potential overloading;
  3319 
  3320 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3321 
  3322 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3323 "{a,b,c}" instead of {a,b,c};
  3324 
  3325 * Isar/Pure now provides its own version of intro/elim/dest
  3326 attributes; useful for building new logics, but beware of confusion
  3327 with the version in Provers/classical;
  3328 
  3329 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3330 case name 'antecedent';
  3331 
  3332 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3333 to the current context is now done automatically);
  3334 
  3335 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3336 for definining proof methods in ML;
  3337 
  3338 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3339 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3340 most cases, one should have to change intro!! to intro? only);
  3341 replaced "delrule" by "rule del";
  3342 
  3343 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3344 'symmetric' attribute (the latter supercedes [RS sym]);
  3345 
  3346 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3347 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3348 well (including splits);
  3349 
  3350 * Isar/Provers: Simplifier and Classical methods now support all kind
  3351 of modifiers used in the past, including 'cong', 'iff', etc.
  3352 
  3353 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3354 of Simplifier and Classical reasoner);
  3355 
  3356 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3357 now support named cases; major packages (inductive, datatype, primrec,
  3358 recdef) support case names and properly name parameters;
  3359 
  3360 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3361 monotonicity conditions are extracted to be proven at end of
  3362 calculations;
  3363 
  3364 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3365 method anyway;
  3366 
  3367 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3368 split_if split_if_asm; datatype package provides theorems foo.splits =
  3369 foo.split foo.split_asm for each datatype;
  3370 
  3371 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3372 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3373 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3374 use "(cases (simplified))" method in proper proof texts);
  3375 
  3376 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3377 
  3378 * Isar: names of theorems etc. may be natural numbers as well;
  3379 
  3380 * Isar: 'pr' command: optional arguments for goals_limit and
  3381 ProofContext.prems_limit; no longer prints theory contexts, but only
  3382 proof states;
  3383 
  3384 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3385 additional print modes to be specified; e.g. "pr(latex)" will print
  3386 proof state according to the Isabelle LaTeX style;
  3387 
  3388 * Isar: improved support for emulating tactic scripts, including proof
  3389 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3390 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3391 (for HOL datatypes);
  3392 
  3393 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3394 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3395 'proof method scripts' have to be in depth-first order;
  3396 
  3397 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3398 
  3399 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3400 should instead use individual commands for printing items
  3401 (print_commands, print_methods etc.);
  3402 
  3403 * Isar: added 'nothing' --- the empty list of theorems;
  3404 
  3405 
  3406 *** HOL ***
  3407 
  3408 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3409 corresponding virtual machine and a specification of its bytecode
  3410 verifier and a lightweight bytecode verifier, including proofs of
  3411 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3412 Cornelia Pusch (see also the homepage of project Bali at
  3413 http://isabelle.in.tum.de/Bali/);
  3414 
  3415 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3416 Clemens Ballarin;
  3417 
  3418 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3419 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3420 Rasmussen;
  3421 
  3422 * HOL/Lattice: fundamental concepts of lattice theory and order
  3423 structures, including duals, properties of bounds versus algebraic
  3424 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3425 Theorem for complete lattices etc.; may also serve as a demonstration
  3426 for abstract algebraic reasoning using axiomatic type classes, and
  3427 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3428 
  3429 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3430 von Oheimb;
  3431 
  3432 * HOL/IMPP: extension of IMP with local variables and mutually
  3433 recursive procedures, by David von Oheimb;
  3434 
  3435 * HOL/Lambda: converted into new-style theory and document;
  3436 
  3437 * HOL/ex/Multiquote: example of multiple nested quotations and
  3438 anti-quotations -- basically a generalized version of de-Bruijn
  3439 representation; very useful in avoiding lifting of operations;
  3440 
  3441 * HOL/record: added general record equality rule to simpset; fixed
  3442 select-update simplification procedure to handle extended records as
  3443 well; admit "r" as field name;
  3444 
  3445 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3446 other numeric types and also as the identity of groups, rings, etc.;
  3447 
  3448 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3449 Types nat and int belong to this axclass;
  3450 
  3451 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3452    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3453    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3454   two terms #m*u and #n*u are replaced by #(m+n)*u
  3455     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3456   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3457     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3458 
  3459 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3460 powerful prover for predicate logic but knows nothing of clasets; see
  3461 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3462 
  3463 * HOL: new version of "case_tac" subsumes both boolean case split and
  3464 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3465 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3466 
  3467 * HOL: simplification no longer dives into case-expressions: only the
  3468 selector expression is simplified, but not the remaining arms; to
  3469 enable full simplification of case-expressions for datatype t, you may
  3470 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3471 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3472 
  3473 * HOL/recdef: the recursion equations generated by 'recdef' for
  3474 function 'f' are now called f.simps instead of f.rules; if all
  3475 termination conditions are proved automatically, these simplification
  3476 rules are added to the simpset, as in primrec; rules may be named
  3477 individually as well, resulting in a separate list of theorems for
  3478 each equation;
  3479 
  3480 * HOL/While is a new theory that provides a while-combinator. It
  3481 permits the definition of tail-recursive functions without the
  3482 provision of a termination measure. The latter is necessary once the
  3483 invariant proof rule for while is applied.
  3484 
  3485 * HOL: new (overloaded) notation for the set of elements below/above
  3486 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3487 
  3488 * HOL: theorems impI, allI, ballI bound as "strip";
  3489 
  3490 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3491 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3492 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3493 
  3494 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3495 
  3496 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3497 main HOL, but was unused);
  3498 
  3499 * HOL: fewer consts declared as global (e.g. have to refer to
  3500 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3501 
  3502 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3503 in case of overlap with user translations (e.g. judgements over
  3504 tuples); (note that the underlying logical represenation is still
  3505 bogus);
  3506 
  3507 
  3508 *** ZF ***
  3509 
  3510 * ZF: simplification automatically cancels common terms in arithmetic
  3511 expressions over nat and int;
  3512 
  3513 * ZF: new treatment of nat to minimize type-checking: all operators
  3514 coerce their operands to a natural number using the function natify,
  3515 making the algebraic laws unconditional;
  3516 
  3517 * ZF: as above, for int: operators coerce their operands to an integer
  3518 using the function intify;
  3519 
  3520 * ZF: the integer library now contains many of the usual laws for the
  3521 orderings, including $<=, and monotonicity laws for $+ and $*;
  3522 
  3523 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3524 simplification;
  3525 
  3526 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3527 to the simplifier and classical reasoner simultaneously;
  3528 
  3529 
  3530 *** General ***
  3531 
  3532 * Provers: blast_tac now handles actual object-logic rules as
  3533 assumptions; note that auto_tac uses blast_tac internally as well;
  3534 
  3535 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3536 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3537 
  3538 * Provers: delrules now handles destruct rules as well (no longer need
  3539 explicit make_elim);
  3540 
  3541 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3542   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3543 use instead the strong form,
  3544   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3545 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3546 from destruct-rules;
  3547 
  3548 * Provers: Simplifier.easy_setup provides a fast path to basic
  3549 Simplifier setup for new object-logics;
  3550 
  3551 * Pure: AST translation rules no longer require constant head on LHS;
  3552 
  3553 * Pure: improved name spaces: ambiguous output is qualified; support
  3554 for hiding of names;
  3555 
  3556 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3557 XSYMBOL_HOME; no longer need to do manual configuration in most
  3558 situations;
  3559 
  3560 * system: compression of ML heaps images may now be controlled via -c
  3561 option of isabelle and isatool usedir (currently only observed by
  3562 Poly/ML);
  3563 
  3564 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3565 useful for remote X11);
  3566 
  3567 * system: provide TAGS file for Isabelle sources;
  3568 
  3569 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3570 order;
  3571 
  3572 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3573 timing flag supersedes proof_timing and Toplevel.trace;
  3574 
  3575 * ML: new combinators |>> and |>>> for incremental transformations
  3576 with secondary results (e.g. certain theory extensions):
  3577 
  3578 * ML: PureThy.add_defs gets additional argument to indicate potential
  3579 overloading (usually false);
  3580 
  3581 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3582 results;
  3583 
  3584 
  3585 
  3586 New in Isabelle99 (October 1999)
  3587 --------------------------------
  3588 
  3589 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3590 
  3591 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3592 are no longer simplified.  (This allows the simplifier to unfold recursive
  3593 functional programs.)  To restore the old behaviour, declare
  3594 
  3595     Delcongs [if_weak_cong];
  3596 
  3597 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3598 complement;
  3599 
  3600 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3601 
  3602 * HOL/datatype: mutual_induct_tac no longer exists --
  3603   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3604 
  3605 * HOL/typedef: fixed type inference for representing set; type
  3606 arguments now have to occur explicitly on the rhs as type constraints;
  3607 
  3608 * ZF: The con_defs part of an inductive definition may no longer refer
  3609 to constants declared in the same theory;
  3610 
  3611 * HOL, ZF: the function mk_cases, generated by the inductive
  3612 definition package, has lost an argument.  To simplify its result, it
  3613 uses the default simpset instead of a supplied list of theorems.
  3614 
  3615 * HOL/List: the constructors of type list are now Nil and Cons;
  3616 
  3617 * Simplifier: the type of the infix ML functions
  3618         setSSolver addSSolver setSolver addSolver
  3619 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3620 for packaging solvers. A solver is created via
  3621         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3622 where the string argument is only a comment.
  3623 
  3624 
  3625 *** Proof tools ***
  3626 
  3627 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3628 decision procedure for linear arithmetic. Currently it is used for
  3629 types `nat', `int', and `real' in HOL (see below); it can, should and
  3630 will be instantiated for other types and logics as well.
  3631 
  3632 * The simplifier now accepts rewrite rules with flexible heads, eg
  3633      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3634   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3635   matching.
  3636 
  3637 
  3638 *** General ***
  3639 
  3640 * New Isabelle/Isar subsystem provides an alternative to traditional
  3641 tactical theorem proving; together with the ProofGeneral/isar user
  3642 interface it offers an interactive environment for developing human
  3643 readable proof documents (Isar == Intelligible semi-automated
  3644 reasoning); for further information see isatool doc isar-ref,
  3645 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3646 
  3647 * improved and simplified presentation of theories: better HTML markup
  3648 (including colors), graph views in several sizes; isatool usedir now
  3649 provides a proper interface for user theories (via -P option); actual
  3650 document preparation based on (PDF)LaTeX is available as well (for
  3651 new-style theories only); see isatool doc system for more information;
  3652 
  3653 * native support for Proof General, both for classic Isabelle and
  3654 Isabelle/Isar;
  3655 
  3656 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3657 using the graph browser tool;
  3658 
  3659 * Isabelle manuals now also available as PDF;
  3660 
  3661 * theory loader rewritten from scratch (may not be fully
  3662 bug-compatible); old loadpath variable has been replaced by show_path,
  3663 add_path, del_path, reset_path functions; new operations such as
  3664 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3665 isatool doc ref);
  3666 
  3667 * improved isatool install: option -k creates KDE application icon,
  3668 option -p DIR installs standalone binaries;
  3669 
  3670 * added ML_PLATFORM setting (useful for cross-platform installations);
  3671 more robust handling of platform specific ML images for SML/NJ;
  3672 
  3673 * the settings environment is now statically scoped, i.e. it is never
  3674 created again in sub-processes invoked from isabelle, isatool, or
  3675 Isabelle;
  3676 
  3677 * path element specification '~~' refers to '$ISABELLE_HOME';
  3678 
  3679 * in locales, the "assumes" and "defines" parts may be omitted if
  3680 empty;
  3681 
  3682 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3683 long arrows);
  3684 
  3685 * new print_mode "HTML";
  3686 
  3687 * new flag show_tags controls display of tags of theorems (which are
  3688 basically just comments that may be attached by some tools);
  3689 
  3690 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3691 mode and goal output format:
  3692 
  3693 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3694 244c244
  3695 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3696 ---
  3697 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3698 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3699 181c181
  3700 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3701 ---
  3702 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3703 
  3704 * function bind_thms stores lists of theorems (cf. bind_thm);
  3705 
  3706 * new shorthand tactics ftac, eatac, datac, fatac;
  3707 
  3708 * qed (and friends) now accept "" as result name; in that case the
  3709 theorem is not stored, but proper checks and presentation of the
  3710 result still apply;
  3711 
  3712 * theorem database now also indexes constants "Trueprop", "all",
  3713 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3714 
  3715 
  3716 *** HOL ***
  3717 
  3718 ** HOL arithmetic **
  3719 
  3720 * There are now decision procedures for linear arithmetic over nat and
  3721 int:
  3722 
  3723 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3724 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3725 are treated as atomic; subformulae not involving type `nat' or `int'
  3726 are ignored; quantified subformulae are ignored unless they are
  3727 positive universal or negative existential. The tactic has to be
  3728 invoked by hand and can be a little bit slow. In particular, the
  3729 running time is exponential in the number of occurrences of `min' and
  3730 `max', and `-' on `nat'.
  3731 
  3732 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3733 (negated) (in)equalities among the premises and the conclusion into
  3734 account (i.e. no compound formulae) and does not know about `min' and
  3735 `max', and `-' on `nat'. It is fast and is used automatically by the
  3736 simplifier.
  3737 
  3738 NB: At the moment, these decision procedures do not cope with mixed
  3739 nat/int formulae where the two parts interact, such as `m < n ==>
  3740 int(m) < int(n)'.
  3741 
  3742 * HOL/Numeral provides a generic theory of numerals (encoded
  3743 efficiently as bit strings); setup for types nat/int/real is in place;
  3744 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3745 int, existing theories and proof scripts may require a few additional
  3746 type constraints;
  3747 
  3748 * integer division and remainder can now be performed on constant
  3749 arguments;
  3750 
  3751 * many properties of integer multiplication, division and remainder
  3752 are now available;
  3753 
  3754 * An interface to the Stanford Validity Checker (SVC) is available through the
  3755 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3756 are proved automatically.  SVC must be installed separately, and its results
  3757 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3758 invocation of the underlying oracle).  For SVC see
  3759   http://verify.stanford.edu/SVC
  3760 
  3761 * IsaMakefile: the HOL-Real target now builds an actual image;
  3762 
  3763 
  3764 ** HOL misc **
  3765 
  3766 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3767 (in Isabelle/Isar) -- by Gertrud Bauer;
  3768 
  3769 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3770 analysis for assembly languages with subtypes;
  3771 
  3772 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3773 -- avoids syntactic ambiguities and treats state, transition, and
  3774 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3775 changed syntax and (many) tactics;
  3776 
  3777 * HOL/inductive: Now also handles more general introduction rules such
  3778   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3779   theorems are now maintained within the theory (maintained via the
  3780   "mono" attribute);
  3781 
  3782 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3783   (using function types) such as
  3784 
  3785   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3786 
  3787 * HOL/record: record_simproc (part of the default simpset) takes care
  3788 of selectors applied to updated records; record_split_tac is no longer
  3789 part of the default claset; update_defs may now be removed from the
  3790 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3791 
  3792   claset_ref () := claset() addSWrapper record_split_wrapper;
  3793   Delsimprocs [record_simproc]
  3794 
  3795 * HOL/typedef: fixed type inference for representing set; type
  3796 arguments now have to occur explicitly on the rhs as type constraints;
  3797 
  3798 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3799 names rather than an ML expression;
  3800 
  3801 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3802 supplied later.  Program schemes can be defined, such as
  3803     "While B C s = (if B s then While B C (C s) else s)"
  3804 where the well-founded relation can be chosen after B and C have been given.
  3805 
  3806 * HOL/List: the constructors of type list are now Nil and Cons;
  3807 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3808 course, ML tools referring to List.list.op # etc. have to be adapted;
  3809 
  3810 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3811 disabled by default; run isabelle with option -m HOL to get back to
  3812 the original Gordon/HOL-style output;
  3813 
  3814 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3815 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3816 
  3817 * HOL basic syntax simplified (more orthogonal): all variants of
  3818 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3819 Eps operator is provided as well: "SOME x. P[x]";
  3820 
  3821 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3822 
  3823 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3824 thus available for user theories;
  3825 
  3826 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3827 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3828 time;
  3829 
  3830 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3831 several times and then mp;
  3832 
  3833 
  3834 *** LK ***
  3835 
  3836 * the notation <<...>> is now available as a notation for sequences of
  3837 formulas;
  3838 
  3839 * the simplifier is now installed
  3840 
  3841 * the axiom system has been generalized (thanks to Soren Heilmann)
  3842 
  3843 * the classical reasoner now has a default rule database
  3844 
  3845 
  3846 *** ZF ***
  3847 
  3848 * new primrec section allows primitive recursive functions to be given
  3849 directly (as in HOL) over datatypes and the natural numbers;
  3850 
  3851 * new tactics induct_tac and exhaust_tac for induction (or case
  3852 analysis) over datatypes and the natural numbers;
  3853 
  3854 * the datatype declaration of type T now defines the recursor T_rec;
  3855 
  3856 * simplification automatically does freeness reasoning for datatype
  3857 constructors;
  3858 
  3859 * automatic type-inference, with AddTCs command to insert new
  3860 type-checking rules;
  3861 
  3862 * datatype introduction rules are now added as Safe Introduction rules
  3863 to the claset;
  3864 
  3865 * the syntax "if P then x else y" is now available in addition to
  3866 if(P,x,y);
  3867 
  3868 
  3869 *** Internal programming interfaces ***
  3870 
  3871 * tuned simplifier trace output; new flag debug_simp;
  3872 
  3873 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3874 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3875 
  3876 * AxClass.axclass_tac lost the theory argument;
  3877 
  3878 * tuned current_goals_markers semantics: begin / end goal avoids
  3879 printing empty lines;
  3880 
  3881 * removed prs and prs_fn hook, which was broken because it did not
  3882 include \n in its semantics, forcing writeln to add one
  3883 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3884 string -> unit if you really want to output text without newline;
  3885 
  3886 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3887 plain output, interface builders may have to enable 'isabelle_font'
  3888 mode to get Isabelle font glyphs as before;
  3889 
  3890 * refined token_translation interface; INCOMPATIBILITY: output length
  3891 now of type real instead of int;
  3892 
  3893 * theory loader actions may be traced via new ThyInfo.add_hook
  3894 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3895 your own database of information attached to *whole* theories -- as
  3896 opposed to intra-theory data slots offered via TheoryDataFun;
  3897 
  3898 * proper handling of dangling sort hypotheses (at last!);
  3899 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3900 extra sort hypotheses that can be witnessed from the type signature;
  3901 the force_strip_shyps flag is gone, any remaining shyps are simply
  3902 left in the theorem (with a warning issued by strip_shyps_warning);
  3903 
  3904 
  3905 
  3906 New in Isabelle98-1 (October 1998)
  3907 ----------------------------------
  3908 
  3909 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3910 
  3911 * several changes of automated proof tools;
  3912 
  3913 * HOL: major changes to the inductive and datatype packages, including
  3914 some minor incompatibilities of theory syntax;
  3915 
  3916 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3917 called `inj_on';
  3918 
  3919 * HOL: removed duplicate thms in Arith:
  3920   less_imp_add_less  should be replaced by  trans_less_add1
  3921   le_imp_add_le      should be replaced by  trans_le_add1
  3922 
  3923 * HOL: unary minus is now overloaded (new type constraints may be
  3924 required);
  3925 
  3926 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3927 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3928 now taken as an integer constant.
  3929 
  3930 * Pure: ML function 'theory_of' renamed to 'theory';
  3931 
  3932 
  3933 *** Proof tools ***
  3934 
  3935 * Simplifier:
  3936   1. Asm_full_simp_tac is now more aggressive.
  3937      1. It will sometimes reorient premises if that increases their power to
  3938         simplify.
  3939      2. It does no longer proceed strictly from left to right but may also
  3940         rotate premises to achieve further simplification.
  3941      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3942      old Asm_full_simp_tac in that it does not rotate premises.
  3943   2. The simplifier now knows a little bit about nat-arithmetic.
  3944 
  3945 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3946 allows for selected deletion of wrappers, by introduction of names for
  3947 wrapper functionals.  This implies that addbefore, addSbefore,
  3948 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3949 and that adding two tactics with the same name overwrites the first
  3950 one (emitting a warning).
  3951   type wrapper = (int -> tactic) -> (int -> tactic)
  3952   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3953   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3954   delWrapper, delSWrapper: claset *  string            -> claset
  3955   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3956 
  3957 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3958 semantics; addbefore now affects only the unsafe part of step_tac
  3959 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3960 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3961 by Force_tac;
  3962 
  3963 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3964 compWrapper; added safe wrapper (and access functions for it);
  3965 
  3966 * HOL/split_all_tac is now much faster and fails if there is nothing
  3967 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3968 and the names of the automatically generated variables have changed.
  3969 split_all_tac has moved within claset() from unsafe wrappers to safe
  3970 wrappers, which means that !!-bound variables are split much more
  3971 aggressively, and safe_tac and clarify_tac now split such variables.
  3972 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3973 Note: the same holds for record_split_tac, which does the job of
  3974 split_all_tac for record fields.
  3975 
  3976 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3977 permanently to the default simpset using Addsplits just like
  3978 Addsimps. They can be removed via Delsplits just like
  3979 Delsimps. Lower-case versions are also available.
  3980 
  3981 * HOL/Simplifier: The rule split_if is now part of the default
  3982 simpset. This means that the simplifier will eliminate all occurrences
  3983 of if-then-else in the conclusion of a goal. To prevent this, you can
  3984 either remove split_if completely from the default simpset by
  3985 `Delsplits [split_if]' or remove it in a specific call of the
  3986 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3987 other case splitting rules to/from the default simpset: every datatype
  3988 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3989 t is the name of the datatype).
  3990 
  3991 * Classical reasoner / Simplifier combination: new force_tac (and
  3992 derivatives Force_tac, force) combines rewriting and classical
  3993 reasoning (and whatever other tools) similarly to auto_tac, but is
  3994 aimed to solve the given subgoal completely.
  3995 
  3996 
  3997 *** General ***
  3998 
  3999 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4000 and `goalw': the theory is no longer needed as an explicit argument -
  4001 the current theory context is used; assumptions are no longer returned
  4002 at the ML-level unless one of them starts with ==> or !!; it is
  4003 recommended to convert to these new commands using isatool fixgoal
  4004 (backup your sources first!);
  4005 
  4006 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4007 the current theory context, and 'theory' to lookup stored theories;
  4008 
  4009 * new theory section 'locale' for declaring constants, assumptions and
  4010 definitions that have local scope;
  4011 
  4012 * new theory section 'nonterminals' for purely syntactic types;
  4013 
  4014 * new theory section 'setup' for generic ML setup functions
  4015 (e.g. package initialization);
  4016 
  4017 * the distribution now includes Isabelle icons: see
  4018 lib/logo/isabelle-{small,tiny}.xpm;
  4019 
  4020 * isatool install - install binaries with absolute references to
  4021 ISABELLE_HOME/bin;
  4022 
  4023 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4024 
  4025 * print mode 'emacs' reserved for Isamode;
  4026 
  4027 * support multiple print (ast) translations per constant name;
  4028 
  4029 * theorems involving oracles are now printed with a suffixed [!];
  4030 
  4031 
  4032 *** HOL ***
  4033 
  4034 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4035 
  4036 * HOL/inductive package reorganized and improved: now supports mutual
  4037 definitions such as
  4038 
  4039   inductive EVEN ODD
  4040     intrs
  4041       null "0 : EVEN"
  4042       oddI "n : EVEN ==> Suc n : ODD"
  4043       evenI "n : ODD ==> Suc n : EVEN"
  4044 
  4045 new theorem list "elims" contains an elimination rule for each of the
  4046 recursive sets; inductive definitions now handle disjunctive premises
  4047 correctly (also ZF);
  4048 
  4049 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4050 "mutual_induct" no longer exists - the induction rule is always
  4051 contained in "induct";
  4052 
  4053 
  4054 * HOL/datatype package re-implemented and greatly improved: now
  4055 supports mutually recursive datatypes such as
  4056 
  4057   datatype
  4058     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4059             | SUM ('a aexp) ('a aexp)
  4060             | DIFF ('a aexp) ('a aexp)
  4061             | NUM 'a
  4062   and
  4063     'a bexp = LESS ('a aexp) ('a aexp)
  4064             | AND ('a bexp) ('a bexp)
  4065             | OR ('a bexp) ('a bexp)
  4066 
  4067 as well as indirectly recursive datatypes such as
  4068 
  4069   datatype
  4070     ('a, 'b) term = Var 'a
  4071                   | App 'b ((('a, 'b) term) list)
  4072 
  4073 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4074 induction on mutually / indirectly recursive datatypes.
  4075 
  4076 Primrec equations are now stored in theory and can be accessed via
  4077 <function_name>.simps.
  4078 
  4079 INCOMPATIBILITIES:
  4080 
  4081   - Theories using datatypes must now have theory Datatype as an
  4082     ancestor.
  4083   - The specific <typename>.induct_tac no longer exists - use the
  4084     generic induct_tac instead.
  4085   - natE has been renamed to nat.exhaust - use exhaust_tac
  4086     instead of res_inst_tac ... natE. Note that the variable
  4087     names in nat.exhaust differ from the names in natE, this
  4088     may cause some "fragile" proofs to fail.
  4089   - The theorems split_<typename>_case and split_<typename>_case_asm
  4090     have been renamed to <typename>.split and <typename>.split_asm.
  4091   - Since default sorts of type variables are now handled correctly,
  4092     some datatype definitions may have to be annotated with explicit
  4093     sort constraints.
  4094   - Primrec definitions no longer require function name and type
  4095     of recursive argument.
  4096 
  4097 Consider using isatool fixdatatype to adapt your theories and proof
  4098 scripts to the new package (backup your sources first!).
  4099 
  4100 
  4101 * HOL/record package: considerably improved implementation; now
  4102 includes concrete syntax for record types, terms, updates; theorems
  4103 for surjective pairing and splitting !!-bound record variables; proof
  4104 support is as follows:
  4105 
  4106   1) standard conversions (selectors or updates applied to record
  4107 constructor terms) are part of the standard simpset;
  4108 
  4109   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4110 made part of standard simpset and claset via addIffs;
  4111 
  4112   3) a tactic for record field splitting (record_split_tac) is part of
  4113 the standard claset (addSWrapper);
  4114 
  4115 To get a better idea about these rules you may retrieve them via
  4116 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4117 the name of your record type.
  4118 
  4119 The split tactic 3) conceptually simplifies by the following rule:
  4120 
  4121   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4122 
  4123 Thus any record variable that is bound by meta-all will automatically
  4124 blow up into some record constructor term, consequently the
  4125 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4126 solve record problems automatically.
  4127 
  4128 
  4129 * reorganized the main HOL image: HOL/Integ and String loaded by
  4130 default; theory Main includes everything;
  4131 
  4132 * automatic simplification of integer sums and comparisons, using cancellation;
  4133 
  4134 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4135 
  4136 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4137 
  4138 * many new identities for unions, intersections, set difference, etc.;
  4139 
  4140 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4141 called split_if, split_split, split_sum_case and split_nat_case (to go
  4142 with add/delsplits);
  4143 
  4144 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4145 (?x::unit) = (); this is made part of the default simpset, which COULD
  4146 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4147 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4148 unit_abs_eta_conv is added in order to counter the effect of
  4149 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4150 %u.f();
  4151 
  4152 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4153 makes more sense);
  4154 
  4155 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4156   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4157   disjointness reasoning but breaking a few old proofs.
  4158 
  4159 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4160 to 'converse' from 'inverse' (for compatibility with ZF and some
  4161 literature);
  4162 
  4163 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4164 the well-founded relation;
  4165 
  4166 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4167     Compl A.  The "Compl" syntax remains available as input syntax for this
  4168     release ONLY.
  4169 
  4170 * HOL/Update: new theory of function updates:
  4171     f(a:=b) == %x. if x=a then b else f x
  4172 may also be iterated as in f(a:=b,c:=d,...);
  4173 
  4174 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4175 
  4176 * HOL/List:
  4177   - new function list_update written xs[i:=v] that updates the i-th
  4178     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4179   - new function `upt' written [i..j(] which generates the list
  4180     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4181     bound write [i..j], which is a shorthand for [i..j+1(].
  4182   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4183 
  4184 * HOL/Arith:
  4185   - removed 'pred' (predecessor) function;
  4186   - generalized some theorems about n-1;
  4187   - many new laws about "div" and "mod";
  4188   - new laws about greatest common divisors (see theory ex/Primes);
  4189 
  4190 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4191 instead of "inverse";
  4192 
  4193 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4194   of the multiset ordering;
  4195 
  4196 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4197   (not included by default);
  4198 
  4199 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4200 
  4201 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4202   programs, i.e. different program variables may have different types.
  4203 
  4204 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4205   [previously, this check worked only if the rewrite rule was unconditional]
  4206   Now rew can involve either definitions or equalities (either == or =).
  4207 
  4208 
  4209 *** ZF ***
  4210 
  4211 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4212   only the theorems proved on ZF.ML;
  4213 
  4214 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4215   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4216   disjointness reasoning but breaking a few old proofs.
  4217 
  4218 * ZF/Update: new theory of function updates
  4219     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4220   may also be iterated as in f(a:=b,c:=d,...);
  4221 
  4222 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4223 
  4224 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4225   [previously, this check worked only if the rewrite rule was unconditional]
  4226   Now rew can involve either definitions or equalities (either == or =).
  4227 
  4228 * case_tac provided for compatibility with HOL
  4229     (like the old excluded_middle_tac, but with subgoals swapped)
  4230 
  4231 
  4232 *** Internal programming interfaces ***
  4233 
  4234 * Pure: several new basic modules made available for general use, see
  4235 also src/Pure/README;
  4236 
  4237 * improved the theory data mechanism to support encapsulation (data
  4238 kind name replaced by private Object.kind, acting as authorization
  4239 key); new type-safe user interface via functor TheoryDataFun; generic
  4240 print_data function becomes basically useless;
  4241 
  4242 * removed global_names compatibility flag -- all theory declarations
  4243 are qualified by default;
  4244 
  4245 * module Pure/Syntax now offers quote / antiquote translation
  4246 functions (useful for Hoare logic etc. with implicit dependencies);
  4247 see HOL/ex/Antiquote for an example use;
  4248 
  4249 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4250 cterm -> thm;
  4251 
  4252 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4253 subgoal;
  4254 
  4255 * Display.print_goals function moved to Locale.print_goals;
  4256 
  4257 * standard print function for goals supports current_goals_markers
  4258 variable for marking begin of proof, end of proof, start of goal; the
  4259 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4260 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4261 for example;
  4262 
  4263 
  4264 
  4265 New in Isabelle98 (January 1998)
  4266 --------------------------------
  4267 
  4268 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4269 
  4270 * changed lexical syntax of terms / types: dots made part of long
  4271 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4272 
  4273 * simpset (and claset) reference variable replaced by functions
  4274 simpset / simpset_ref;
  4275 
  4276 * no longer supports theory aliases (via merge) and non-trivial
  4277 implicit merge of thms' signatures;
  4278 
  4279 * most internal names of constants changed due to qualified names;
  4280 
  4281 * changed Pure/Sequence interface (see Pure/seq.ML);
  4282 
  4283 
  4284 *** General Changes ***
  4285 
  4286 * hierachically structured name spaces (for consts, types, axms, thms
  4287 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4288 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4289 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4290 long_names for fully qualified output names; NOTE: ML programs
  4291 (special tactics, packages etc.) referring to internal names may have
  4292 to be adapted to cope with fully qualified names; in case of severe
  4293 backward campatibility problems try setting 'global_names' at compile
  4294 time to have enrything declared within a flat name space; one may also
  4295 fine tune name declarations in theories via the 'global' and 'local'
  4296 section;
  4297 
  4298 * reimplemented the implicit simpset and claset using the new anytype
  4299 data filed in signatures; references simpset:simpset ref etc. are
  4300 replaced by functions simpset:unit->simpset and
  4301 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4302 to patch your ML files accordingly;
  4303 
  4304 * HTML output now includes theory graph data for display with Java
  4305 applet or isatool browser; data generated automatically via isatool
  4306 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4307 
  4308 * defs may now be conditional; improved rewrite_goals_tac to handle
  4309 conditional equations;
  4310 
  4311 * defs now admits additional type arguments, using TYPE('a) syntax;
  4312 
  4313 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4314 creates a new theory node; implicit merge of thms' signatures is
  4315 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4316 transfer:theory->thm->thm in (rare) cases;
  4317 
  4318 * improved handling of draft signatures / theories; draft thms (and
  4319 ctyps, cterms) are automatically promoted to real ones;
  4320 
  4321 * slightly changed interfaces for oracles: admit many per theory, named
  4322 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4323 
  4324 * print_goals: optional output of const types (set show_consts and
  4325 show_types);
  4326 
  4327 * improved output of warnings (###) and errors (***);
  4328 
  4329 * subgoal_tac displays a warning if the new subgoal has type variables;
  4330 
  4331 * removed old README and Makefiles;
  4332 
  4333 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4334 
  4335 * removed obsolete init_pps and init_database;
  4336 
  4337 * deleted the obsolete tactical STATE, which was declared by
  4338     fun STATE tacfun st = tacfun st st;
  4339 
  4340 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4341 (which abbreviates $HOME);
  4342 
  4343 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4344 use isatool fixseq to adapt your ML programs (this works for fully
  4345 qualified references to the Sequence structure only!);
  4346 
  4347 * use_thy no longer requires writable current directory; it always
  4348 reloads .ML *and* .thy file, if either one is out of date;
  4349 
  4350 
  4351 *** Classical Reasoner ***
  4352 
  4353 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4354 tactics that use classical reasoning to simplify a subgoal without
  4355 splitting it into several subgoals;
  4356 
  4357 * Safe_tac: like safe_tac but uses the default claset;
  4358 
  4359 
  4360 *** Simplifier ***
  4361 
  4362 * added simplification meta rules:
  4363     (asm_)(full_)simplify: simpset -> thm -> thm;
  4364 
  4365 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4366 logics (again);
  4367 
  4368 * added prems argument to simplification procedures;
  4369 
  4370 * HOL, FOL, ZF: added infix function `addsplits':
  4371   instead of `<simpset> setloop (split_tac <thms>)'
  4372   you can simply write `<simpset> addsplits <thms>'
  4373 
  4374 
  4375 *** Syntax ***
  4376 
  4377 * TYPE('a) syntax for type reflection terms;
  4378 
  4379 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4380 
  4381 * pretty printer: changed order of mixfix annotation preference (again!);
  4382 
  4383 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4384 
  4385 
  4386 *** HOL ***
  4387 
  4388 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4389   with `addloop' of the simplifier to faciliate case splitting in premises.
  4390 
  4391 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4392 
  4393 * HOL/Auth: new protocol proofs including some for the Internet
  4394   protocol TLS;
  4395 
  4396 * HOL/Map: new theory of `maps' a la VDM;
  4397 
  4398 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4399 cancelling out common nat summands from =, <, <= (in)equalities, or
  4400 differences; simplification procedures nat_cancel_factor for
  4401 cancelling common factor from =, <, <= (in)equalities over natural
  4402 sums; nat_cancel contains both kinds of procedures, it is installed by
  4403 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4404 
  4405 * HOL/simplifier: terms of the form
  4406   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4407   are rewritten to
  4408   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4409   and those of the form
  4410   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4411   are rewritten to
  4412   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4413 
  4414 * HOL/datatype
  4415   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4416 
  4417   P(t_case f1 ... fn x) =
  4418      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4419         ...
  4420        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4421      )
  4422 
  4423   and a theorem `split_t_case_asm' of the form
  4424 
  4425   P(t_case f1 ... fn x) =
  4426     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4427         ...
  4428        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4429      )
  4430   which can be added to a simpset via `addsplits'. The existing theorems
  4431   expand_list_case and expand_option_case have been renamed to
  4432   split_list_case and split_option_case.
  4433 
  4434 * HOL/Arithmetic:
  4435   - `pred n' is automatically converted to `n-1'.
  4436     Users are strongly encouraged not to use `pred' any longer,
  4437     because it will disappear altogether at some point.
  4438   - Users are strongly encouraged to write "0 < n" rather than
  4439     "n ~= 0". Theorems and proof tools have been modified towards this
  4440     `standard'.
  4441 
  4442 * HOL/Lists:
  4443   the function "set_of_list" has been renamed "set" (and its theorems too);
  4444   the function "nth" now takes its arguments in the reverse order and
  4445   has acquired the infix notation "!" as in "xs!n".
  4446 
  4447 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4448 
  4449 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4450   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4451 
  4452 * HOL/record: extensible records with schematic structural subtyping
  4453 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4454 still lacks various theorems and concrete record syntax;
  4455 
  4456 
  4457 *** HOLCF ***
  4458 
  4459 * removed "axioms" and "generated by" sections;
  4460 
  4461 * replaced "ops" section by extended "consts" section, which is capable of
  4462   handling the continuous function space "->" directly;
  4463 
  4464 * domain package:
  4465   . proves theorems immediately and stores them in the theory,
  4466   . creates hierachical name space,
  4467   . now uses normal mixfix annotations (instead of cinfix...),
  4468   . minor changes to some names and values (for consistency),
  4469   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4470   . separator between mutual domain defs: changed "," to "and",
  4471   . improved handling of sort constraints;  now they have to
  4472     appear on the left-hand side of the equations only;
  4473 
  4474 * fixed LAM <x,y,zs>.b syntax;
  4475 
  4476 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4477 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4478 
  4479 
  4480 *** FOL and ZF ***
  4481 
  4482 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4483   with `addloop' of the simplifier to faciliate case splitting in premises.
  4484 
  4485 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4486 in HOL, they strip ALL and --> from proved theorems;
  4487 
  4488 
  4489 
  4490 New in Isabelle94-8 (May 1997)
  4491 ------------------------------
  4492 
  4493 *** General Changes ***
  4494 
  4495 * new utilities to build / run / maintain Isabelle etc. (in parts
  4496 still somewhat experimental); old Makefiles etc. still functional;
  4497 
  4498 * new 'Isabelle System Manual';
  4499 
  4500 * INSTALL text, together with ./configure and ./build scripts;
  4501 
  4502 * reimplemented type inference for greater efficiency, better error
  4503 messages and clean internal interface;
  4504 
  4505 * prlim command for dealing with lots of subgoals (an easier way of
  4506 setting goals_limit);
  4507 
  4508 
  4509 *** Syntax ***
  4510 
  4511 * supports alternative (named) syntax tables (parser and pretty
  4512 printer); internal interface is provided by add_modesyntax(_i);
  4513 
  4514 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4515 be used in conjunction with the Isabelle symbol font; uses the
  4516 "symbols" syntax table;
  4517 
  4518 * added token_translation interface (may translate name tokens in
  4519 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4520 the current print_mode); IMPORTANT: user print translation functions
  4521 are responsible for marking newly introduced bounds
  4522 (Syntax.mark_boundT);
  4523 
  4524 * token translations for modes "xterm" and "xterm_color" that display
  4525 names in bold, underline etc. or colors (which requires a color
  4526 version of xterm);
  4527 
  4528 * infixes may now be declared with names independent of their syntax;
  4529 
  4530 * added typed_print_translation (like print_translation, but may
  4531 access type of constant);
  4532 
  4533 
  4534 *** Classical Reasoner ***
  4535 
  4536 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4537 some limitations.  Blast_tac...
  4538   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4539   + ignores elimination rules that don't have the correct format
  4540         (the conclusion MUST be a formula variable)
  4541   + ignores types, which can make HOL proofs fail
  4542   + rules must not require higher-order unification, e.g. apply_type in ZF
  4543     [message "Function Var's argument not a bound variable" relates to this]
  4544   + its proof strategy is more general but can actually be slower
  4545 
  4546 * substitution with equality assumptions no longer permutes other
  4547 assumptions;
  4548 
  4549 * minor changes in semantics of addafter (now called addaltern); renamed
  4550 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4551 (and access functions for it);
  4552 
  4553 * improved combination of classical reasoner and simplifier:
  4554   + functions for handling clasimpsets
  4555   + improvement of addss: now the simplifier is called _after_ the
  4556     safe steps.
  4557   + safe variant of addss called addSss: uses safe simplifications
  4558     _during_ the safe steps. It is more complete as it allows multiple
  4559     instantiations of unknowns (e.g. with slow_tac).
  4560 
  4561 *** Simplifier ***
  4562 
  4563 * added interface for simplification procedures (functions that
  4564 produce *proven* rewrite rules on the fly, depending on current
  4565 redex);
  4566 
  4567 * ordering on terms as parameter (used for ordered rewriting);
  4568 
  4569 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4570 
  4571 * the solver is now split into a safe and an unsafe part.
  4572 This should be invisible for the normal user, except that the
  4573 functions setsolver and addsolver have been renamed to setSolver and
  4574 addSolver; added safe_asm_full_simp_tac;
  4575 
  4576 
  4577 *** HOL ***
  4578 
  4579 * a generic induction tactic `induct_tac' which works for all datatypes and
  4580 also for type `nat';
  4581 
  4582 * a generic case distinction tactic `exhaust_tac' which works for all
  4583 datatypes and also for type `nat';
  4584 
  4585 * each datatype comes with a function `size';
  4586 
  4587 * patterns in case expressions allow tuple patterns as arguments to
  4588 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4589 
  4590 * primrec now also works with type nat;
  4591 
  4592 * recdef: a new declaration form, allows general recursive functions to be
  4593 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4594 
  4595 * the constant for negation has been renamed from "not" to "Not" to
  4596 harmonize with FOL, ZF, LK, etc.;
  4597 
  4598 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4599 infinite lists;
  4600 
  4601 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4602 
  4603 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4604 problems in commutative rings, using axiomatic type classes for + and *;
  4605 
  4606 * more examples in HOL/MiniML and HOL/Auth;
  4607 
  4608 * more default rewrite rules for quantifiers, union/intersection;
  4609 
  4610 * a new constant `arbitrary == @x.False';
  4611 
  4612 * HOLCF/IOA replaces old HOL/IOA;
  4613 
  4614 * HOLCF changes: derived all rules and arities
  4615   + axiomatic type classes instead of classes
  4616   + typedef instead of faking type definitions
  4617   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4618   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4619   + eliminated the types void, one, tr
  4620   + use unit lift and bool lift (with translations) instead of one and tr
  4621   + eliminated blift from Lift3.thy (use Def instead of blift)
  4622   all eliminated rules are derived as theorems --> no visible changes ;
  4623 
  4624 
  4625 *** ZF ***
  4626 
  4627 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4628 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4629 as ZF_cs addSIs [equalityI];
  4630 
  4631 
  4632 
  4633 New in Isabelle94-7 (November 96)
  4634 ---------------------------------
  4635 
  4636 * allowing negative levels (as offsets) in prlev and choplev;
  4637 
  4638 * super-linear speedup for large simplifications;
  4639 
  4640 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4641 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4642 FAIL); can suppress it using the command Delsimps (ex_simps @
  4643 all_simps); De Morgan laws are also now included, by default;
  4644 
  4645 * improved printing of ==>  :  ~:
  4646 
  4647 * new object-logic "Sequents" adds linear logic, while replacing LK
  4648 and Modal (thanks to Sara Kalvala);
  4649 
  4650 * HOL/Auth: correctness proofs for authentication protocols;
  4651 
  4652 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4653 examples on HOL/Auth);
  4654 
  4655 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4656 the rewriter and classical reasoner simultaneously;
  4657 
  4658 * function uresult no longer returns theorems in "standard" format;
  4659 regain previous version by: val uresult = standard o uresult;
  4660 
  4661 
  4662 
  4663 New in Isabelle94-6
  4664 -------------------
  4665 
  4666 * oracles -- these establish an interface between Isabelle and trusted
  4667 external reasoners, which may deliver results as theorems;
  4668 
  4669 * proof objects (in particular record all uses of oracles);
  4670 
  4671 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4672 
  4673 * "constdefs" section in theory files;
  4674 
  4675 * "primrec" section (HOL) no longer requires names;
  4676 
  4677 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4678 
  4679 
  4680 
  4681 New in Isabelle94-5
  4682 -------------------
  4683 
  4684 * reduced space requirements;
  4685 
  4686 * automatic HTML generation from theories;
  4687 
  4688 * theory files no longer require "..." (quotes) around most types;
  4689 
  4690 * new examples, including two proofs of the Church-Rosser theorem;
  4691 
  4692 * non-curried (1994) version of HOL is no longer distributed;
  4693 
  4694 
  4695 
  4696 New in Isabelle94-4
  4697 -------------------
  4698 
  4699 * greatly reduced space requirements;
  4700 
  4701 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4702 
  4703 * searchable theorem database (see the section "Retrieving theorems" on
  4704 page 8 of the Reference Manual);
  4705 
  4706 * new examples, including Grabczewski's monumental case study of the
  4707 Axiom of Choice;
  4708 
  4709 * The previous version of HOL renamed to Old_HOL;
  4710 
  4711 * The new version of HOL (previously called CHOL) uses a curried syntax
  4712 for functions.  Application looks like f a b instead of f(a,b);
  4713 
  4714 * Mutually recursive inductive definitions finally work in HOL;
  4715 
  4716 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4717 translates to the operator "split";
  4718 
  4719 
  4720 
  4721 New in Isabelle94-3
  4722 -------------------
  4723 
  4724 * new infix operator, addss, allowing the classical reasoner to
  4725 perform simplification at each step of its search.  Example:
  4726         fast_tac (cs addss ss)
  4727 
  4728 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4729 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4730 look like (a,b) instead of <a,b>;
  4731 
  4732 * PLEASE NOTE: CHOL will eventually replace HOL!
  4733 
  4734 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4735 It translates to the operator "split".  A new theory of integers is available;
  4736 
  4737 * In ZF, integer numerals now denote two's-complement binary integers.
  4738 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4739 
  4740 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4741 of the Axiom of Choice;
  4742 
  4743 
  4744 
  4745 New in Isabelle94-2
  4746 -------------------
  4747 
  4748 * Significantly faster resolution;
  4749 
  4750 * the different sections in a .thy file can now be mixed and repeated
  4751 freely;
  4752 
  4753 * Database of theorems for FOL, HOL and ZF.  New
  4754 commands including qed, qed_goal and bind_thm store theorems in the database.
  4755 
  4756 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4757 a given theory (thms_of), or find out what theory a theorem was proved in
  4758 (theory_of_thm);
  4759 
  4760 * Bugs fixed in the inductive definition and datatype packages;
  4761 
  4762 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4763 and HOL_dup_cs obsolete;
  4764 
  4765 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4766 have been removed;
  4767 
  4768 * Simpler definition of function space in ZF;
  4769 
  4770 * new results about cardinal and ordinal arithmetic in ZF;
  4771 
  4772 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4773 types;
  4774 
  4775 
  4776 $Id$