NEWS
author wenzelm
Wed Jun 13 10:44:35 2007 +0200 (2007-06-13)
changeset 23367 05f399115ba5
parent 23300 b785068bd5dc
child 23369 227c51012cdb
permissions -rw-r--r--
tuned;
     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). FUTURE INCOMPATIBILITY:
    12 legacy features will disappear eventually.
    13 
    14 * Theory syntax: the header format ``theory A = B + C:'' has been
    15 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    16 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    17 
    18 * Theory syntax: the old non-Isar theory file format has been
    19 discontinued altogether.  Note that ML proof scripts may still be used
    20 with Isar theories; migration is usually quite simple with the ML
    21 function use_legacy_bindings.  INCOMPATIBILITY.
    22 
    23 * Theory syntax: some popular names (e.g. 'class', 'declaration',
    24 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
    25 quotes.
    26 
    27 * Legacy goal package: reduced interface to the bare minimum required
    28 to keep existing proof scripts running.  Most other user-level
    29 functions are now part of the OldGoals structure, which is *not* open
    30 by default (consider isatool expandshort before open OldGoals).
    31 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    32 these tend to cause confusion about the actual goal (!) context being
    33 used here, which is not necessarily the same as the_context().
    34 
    35 * Command 'find_theorems': supports "*" wildcard in "name:" criterion.
    36 
    37 * Proof General interface: A search form for the "Find Theorems" command is
    38 now available via C-c C-a C-f.  The old minibuffer interface is available
    39 via C-c C-a C-m.  Variable proof-find-theorems-command (customizable via
    40 'Proof-General -> Advanced -> Internals -> Prover Config') controls the
    41 default behavior of 'ProofGeneral -> Find Theorems' (C-c C-f): set to
    42 isar-find-theorems-form or isar-find-theorems-minibuffer.
    43 
    44 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    45 by default, which means that "prems" (and also "fixed variables") are
    46 suppressed from proof state output.  Note that the ProofGeneral
    47 settings mechanism allows to change and save options persistently, but
    48 older versions of Isabelle will fail to start up if a negative prems
    49 limit is imposed.
    50 
    51 * Local theory targets may be specified by non-nested blocks of
    52 ``context/locale/class ... begin'' followed by ``end''.  The body may
    53 contain definitions, theorems etc., including any derived mechanism
    54 that has been implemented on top of these primitives.  This concept
    55 generalizes the existing ``theorem (in ...)'' towards more versatility
    56 and scalability.
    57 
    58 * Proof General interface: proper undo of final 'end' command;
    59 discontinued Isabelle/classic mode (ML proof scripts).
    60 
    61 
    62 *** Document preparation ***
    63 
    64 * Added antiquotation @{theory name} which prints the given name,
    65 after checking that it refers to a valid ancestor theory in the
    66 current context.
    67 
    68 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    69 check the given source text as ML type/structure, printing verbatim.
    70 
    71 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    72 "c args == rhs" given in the current context.  (Any number of
    73 arguments may be given on the LHS.)
    74 
    75 
    76 
    77 *** Pure ***
    78 
    79 * code generator: consts in 'consts_code' Isar commands are now referred
    80   to by usual term syntax (including optional type annotations).
    81 
    82 * code generator: 
    83   - Isar 'definition's, 'constdef's and primitive instance definitions are added
    84     explicitly to the table of defining equations
    85   - primitive definitions are not used as defining equations by default any longer
    86   - defining equations are now definitly restricted to meta "==" and object
    87         equality "="
    88   - HOL theories have been adopted accordingly
    89 
    90 * class_package.ML offers a combination of axclasses and locales to
    91 achieve Haskell-like type classes in Isabelle.  See
    92 HOL/ex/Classpackage.thy for examples.
    93 
    94 * Yet another code generator framework allows to generate executable
    95 code for ML and Haskell (including "class"es).  A short usage sketch:
    96 
    97     internal compilation:
    98         code_gen <list of constants (term syntax)> (SML #)
    99     writing SML code to a file:
   100         code_gen <list of constants (term syntax)> (SML <filename>)
   101     writing OCaml code to a file:
   102         code_gen <list of constants (term syntax)> (OCaml <filename>)
   103     writing Haskell code to a bunch of files:
   104         code_gen <list of constants (term syntax)> (Haskell <filename>)
   105 
   106 Reasonable default setup of framework in HOL/Main.
   107 
   108 Theorem attributs for selecting and transforming function equations theorems:
   109 
   110     [code fun]:        select a theorem as function equation for a specific constant
   111     [code fun del]:    deselect a theorem as function equation for a specific constant
   112     [code inline]:     select an equation theorem for unfolding (inlining) in place
   113     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   114 
   115 User-defined serializations (target in {SML, OCaml, Haskell}):
   116 
   117     code_const <and-list of constants (term syntax)>
   118       {(target) <and-list of const target syntax>}+
   119 
   120     code_type <and-list of type constructors>
   121       {(target) <and-list of type target syntax>}+
   122 
   123     code_instance <and-list of instances>
   124       {(target)}+
   125         where instance ::= <type constructor> :: <class>
   126 
   127     code_class <and_list of classes>
   128       {(target) <and-list of class target syntax>}+
   129         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   130 
   131 code_instance and code_class only apply to target Haskell.
   132 
   133 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   134 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   135 
   136 * Command 'no_translations' removes translation rules from theory
   137 syntax.
   138 
   139 * Overloaded definitions are now actually checked for acyclic
   140 dependencies.  The overloading scheme is slightly more general than
   141 that of Haskell98, although Isabelle does not demand an exact
   142 correspondence to type class and instance declarations.
   143 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   144 exotic versions of overloading -- at the discretion of the user!
   145 
   146 Polymorphic constants are represented via type arguments, i.e. the
   147 instantiation that matches an instance against the most general
   148 declaration given in the signature.  For example, with the declaration
   149 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   150 as c(nat).  Overloading is essentially simultaneous structural
   151 recursion over such type arguments.  Incomplete specification patterns
   152 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   153 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   154 Command 'print_theory' outputs the normalized system of recursive
   155 equations, see section "definitions".
   156 
   157 * Isar: improper proof element 'guess' is like 'obtain', but derives
   158 the obtained context from the course of reasoning!  For example:
   159 
   160   assume "EX x y. A x & B y"   -- "any previous fact"
   161   then guess x and y by clarify
   162 
   163 This technique is potentially adventurous, depending on the facts and
   164 proof tools being involved here.
   165 
   166 * Isar: known facts from the proof context may be specified as literal
   167 propositions, using ASCII back-quote syntax.  This works wherever
   168 named facts used to be allowed so far, in proof commands, proof
   169 methods, attributes etc.  Literal facts are retrieved from the context
   170 according to unification of type and term parameters.  For example,
   171 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   172 theorems in the current context, then these are valid literal facts:
   173 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   174 
   175 There is also a proof method "fact" which does the same composition
   176 for explicit goal states, e.g. the following proof texts coincide with
   177 certain special cases of literal facts:
   178 
   179   have "A" by fact                 ==  note `A`
   180   have "A ==> B" by fact           ==  note `A ==> B`
   181   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   182   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   183 
   184 * Isar: ":" (colon) is no longer a symbolic identifier character in
   185 outer syntax.  Thus symbolic identifiers may be used without
   186 additional white space in declarations like this: ``assume *: A''.
   187 
   188 * Isar: 'print_facts' prints all local facts of the current context,
   189 both named and unnamed ones.
   190 
   191 * Isar: 'def' now admits simultaneous definitions, e.g.:
   192 
   193   def x == "t" and y == "u"
   194 
   195 * Isar: added command 'unfolding', which is structurally similar to
   196 'using', but affects both the goal state and facts by unfolding given
   197 rewrite rules.  Thus many occurrences of the 'unfold' method or
   198 'unfolded' attribute may be replaced by first-class proof text.
   199 
   200 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   201 and command 'unfolding' now all support object-level equalities
   202 (potentially conditional).  The underlying notion of rewrite rule is
   203 analogous to the 'rule_format' attribute, but *not* that of the
   204 Simplifier (which is usually more generous).
   205 
   206 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   207 method expression within a sandbox consisting of the first N
   208 sub-goals, which need to exist.  For example, ``simp_all [3]''
   209 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   210 simplifies all new goals that emerge from applying rule foo to the
   211 originally first one.
   212 
   213 * Isar: schematic goals are no longer restricted to higher-order
   214 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   215 expected.
   216 
   217 * Isar: the conclusion of a long theorem statement is now either
   218 'shows' (a simultaneous conjunction, as before), or 'obtains'
   219 (essentially a disjunction of cases with local parameters and
   220 assumptions).  The latter allows to express general elimination rules
   221 adequately; in this notation common elimination rules look like this:
   222 
   223   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   224     assumes "EX x. P x"
   225     obtains x where "P x"
   226 
   227   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   228     assumes "A & B"
   229     obtains A and B
   230 
   231   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   232     assumes "A | B"
   233     obtains
   234       A
   235     | B
   236 
   237 The subsequent classical rules even refer to the formal "thesis"
   238 explicitly:
   239 
   240   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   241     obtains "~ thesis"
   242 
   243   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   244     obtains "thesis ==> something"
   245 
   246 The actual proof of an 'obtains' statement is analogous to that of the
   247 Isar proof element 'obtain', only that there may be several cases.
   248 Optional case names may be specified in parentheses; these will be
   249 available both in the present proof and as annotations in the
   250 resulting rule, for later use with the 'cases' method (cf. attribute
   251 case_names).
   252 
   253 * Isar: the assumptions of a long theorem statement are available as
   254 "assms" fact in the proof context.  This is more appropriate than the
   255 (historical) "prems", which refers to all assumptions of the current
   256 context, including those from the target locale, proof body etc.
   257 
   258 * Isar: 'print_statement' prints theorems from the current theory or
   259 proof context in long statement form, according to the syntax of a
   260 top-level lemma.
   261 
   262 * Isar: 'obtain' takes an optional case name for the local context
   263 introduction rule (default "that").
   264 
   265 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   266 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   267 to occur.
   268 
   269 * Pure: syntax "CONST name" produces a fully internalized constant
   270 according to the current context.  This is particularly useful for
   271 syntax translations that should refer to internal constant
   272 representations independently of name spaces.
   273 
   274 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   275 instead of "FOO ". This allows multiple binder declarations to coexist
   276 in the same context.  INCOMPATIBILITY.
   277 
   278 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   279 primitive that also works in a locale context (both for constants and
   280 fixed variables).  Type declaration and internal syntactic
   281 representation of given constants retrieved from the context.
   282 
   283 * Isar/locales: new derived specification elements 'axiomatization',
   284 'definition', 'abbreviation', which support type-inference, admit
   285 object-level specifications (equality, equivalence).  See also the
   286 isar-ref manual.  Examples:
   287 
   288   axiomatization
   289     eq  (infix "===" 50) where
   290     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   291 
   292   definition "f x y = x + y + 1"
   293   definition g where "g x = f x x"
   294 
   295   abbreviation
   296     neq  (infix "=!=" 50) where
   297     "x =!= y == ~ (x === y)"
   298 
   299 These specifications may be also used in a locale context.  Then the
   300 constants being introduced depend on certain fixed parameters, and the
   301 constant name is qualified by the locale base name.  An internal
   302 abbreviation takes care for convenient input and output, making the
   303 parameters implicit and using the original short name.  See also
   304 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   305 entities from a monomorphic theory.
   306 
   307 Presently, abbreviations are only available 'in' a target locale, but
   308 not inherited by general import expressions.  Also note that
   309 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   310 'translations' in common applications.
   311 
   312 Concrete syntax is attached to specified constants in internal form,
   313 independently of name spaces.  The parse tree representation is
   314 slightly different -- use 'notation' instead of raw 'syntax', and
   315 'translations' with explicit "CONST" markup to accommodate this.
   316 
   317 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   318 the current context.  Print mode "no_abbrevs" prevents inversion of
   319 abbreviations on output.
   320 
   321 * Isar/locales: improved parameter handling:
   322 - use of locales "var" and "struct" no longer necessary;
   323 - parameter renamings are no longer required to be injective.
   324   This enables, for example, to define a locale for endomorphisms thus:
   325   locale endom = homom mult mult h.
   326 
   327 * Isar/locales: changed the way locales with predicates are defined.
   328 Instead of accumulating the specification, the imported expression is
   329 now an interpretation.  INCOMPATIBILITY: different normal form of
   330 locale expressions.  In particular, in interpretations of locales with
   331 predicates, goals repesenting already interpreted fragments are not
   332 removed automatically.  Use methods `intro_locales' and
   333 `unfold_locales'; see below.
   334 
   335 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   336 provide backward reasoning on locales predicates.  The methods are
   337 aware of interpretations and discharge corresponding goals.
   338 `intro_locales' is less aggressive then `unfold_locales' and does not
   339 unfold predicates to assumptions.
   340 
   341 * Isar/locales: the order in which locale fragments are accumulated
   342 has changed.  This enables to override declarations from fragments due
   343 to interpretations -- for example, unwanted simp rules.
   344 
   345 * Provers/induct: improved internal context management to support
   346 local fixes and defines on-the-fly.  Thus explicit meta-level
   347 connectives !! and ==> are rarely required anymore in inductive goals
   348 (using object-logic connectives for this purpose has been long
   349 obsolete anyway).  The subsequent proof patterns illustrate advanced
   350 techniques of natural induction; general datatypes and inductive sets
   351 work analogously (see also src/HOL/Lambda for realistic examples).
   352 
   353 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   354 parameters:
   355 
   356   lemma
   357     fixes n :: nat and x :: 'a
   358     assumes a: "A n x"
   359     shows "P n x"
   360     using a                     -- {* make induct insert fact a *}
   361   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   362     case 0
   363     show ?case sorry
   364   next
   365     case (Suc n)
   366     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   367     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   368     show ?case sorry
   369   qed
   370 
   371 (2) This is how to perform induction over ``expressions of a certain
   372 form'', using a locally defined inductive parameter n == "a x"
   373 together with strengthening (the latter is usually required to get
   374 sufficiently flexible induction hypotheses):
   375 
   376   lemma
   377     fixes a :: "'a => nat"
   378     assumes a: "A (a x)"
   379     shows "P (a x)"
   380     using a
   381   proof (induct n == "a x" arbitrary: x)
   382     ...
   383 
   384 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   385 particular technique.
   386 
   387 (3) This is how to perform existential reasoning ('obtains' or
   388 'obtain') by induction, while avoiding explicit object-logic
   389 encodings:
   390 
   391   lemma
   392     fixes n :: nat
   393     obtains x :: 'a where "P n x" and "Q n x"
   394   proof (induct n arbitrary: thesis)
   395     case 0
   396     obtain x where "P 0 x" and "Q 0 x" sorry
   397     then show thesis by (rule 0)
   398   next
   399     case (Suc n)
   400     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   401     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   402     then show thesis by (rule Suc.prems)
   403   qed
   404 
   405 Here the 'arbitrary: thesis' specification essentially modifies the
   406 scope of the formal thesis parameter, in order to the get the whole
   407 existence statement through the induction as expected.
   408 
   409 * Provers/induct: mutual induction rules are now specified as a list
   410 of rule sharing the same induction cases.  HOL packages usually
   411 provide foo_bar.inducts for mutually defined items foo and bar
   412 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   413 specify mutual induction rules differently, i.e. like this:
   414 
   415   (induct rule: foo_bar.inducts)
   416   (induct set: foo bar)
   417   (induct type: foo bar)
   418 
   419 The ML function ProjectRule.projections turns old-style rules into the
   420 new format.
   421 
   422 * Provers/induct: improved handling of simultaneous goals.  Instead of
   423 introducing object-level conjunction, the statement is now split into
   424 several conclusions, while the corresponding symbolic cases are
   425 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   426 explicitly.  For example:
   427 
   428   lemma
   429     fixes n :: nat
   430     shows "P n" and "Q n"
   431   proof (induct n)
   432     case 0 case 1
   433     show "P 0" sorry
   434   next
   435     case 0 case 2
   436     show "Q 0" sorry
   437   next
   438     case (Suc n) case 1
   439     note `P n` and `Q n`
   440     show "P (Suc n)" sorry
   441   next
   442     case (Suc n) case 2
   443     note `P n` and `Q n`
   444     show "Q (Suc n)" sorry
   445   qed
   446 
   447 The split into subcases may be deferred as follows -- this is
   448 particularly relevant for goal statements with local premises.
   449 
   450   lemma
   451     fixes n :: nat
   452     shows "A n ==> P n" and "B n ==> Q n"
   453   proof (induct n)
   454     case 0
   455     {
   456       case 1
   457       note `A 0`
   458       show "P 0" sorry
   459     next
   460       case 2
   461       note `B 0`
   462       show "Q 0" sorry
   463     }
   464   next
   465     case (Suc n)
   466     note `A n ==> P n` and `B n ==> Q n`
   467     {
   468       case 1
   469       note `A (Suc n)`
   470       show "P (Suc n)" sorry
   471     next
   472       case 2
   473       note `B (Suc n)`
   474       show "Q (Suc n)" sorry
   475     }
   476   qed
   477 
   478 If simultaneous goals are to be used with mutual rules, the statement
   479 needs to be structured carefully as a two-level conjunction, using
   480 lists of propositions separated by 'and':
   481 
   482   lemma
   483     shows "a : A ==> P1 a"
   484           "a : A ==> P2 a"
   485       and "b : B ==> Q1 b"
   486           "b : B ==> Q2 b"
   487           "b : B ==> Q3 b"
   488   proof (induct set: A B)
   489 
   490 * Provers/induct: support coinduction as well.  See
   491 src/HOL/Library/Coinductive_List.thy for various examples.
   492 
   493 * Attribute "symmetric" produces result with standardized schematic
   494 variables (index 0).  Potential INCOMPATIBILITY.
   495 
   496 * Simplifier: by default the simplifier trace only shows top level
   497 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   498 default. Thus there is less danger of being flooded by the trace. The
   499 trace indicates where parts have been suppressed.
   500   
   501 * Provers/classical: removed obsolete classical version of elim_format
   502 attribute; classical elim/dest rules are now treated uniformly when
   503 manipulating the claset.
   504 
   505 * Provers/classical: stricter checks to ensure that supplied intro,
   506 dest and elim rules are well-formed; dest and elim rules must have at
   507 least one premise.
   508 
   509 * Provers/classical: attributes dest/elim/intro take an optional
   510 weight argument for the rule (just as the Pure versions).  Weights are
   511 ignored by automated tools, but determine the search order of single
   512 rule steps.
   513 
   514 * Syntax: input syntax now supports dummy variable binding "%_. b",
   515 where the body does not mention the bound variable.  Note that dummy
   516 patterns implicitly depend on their context of bounds, which makes
   517 "{_. _}" match any set comprehension as expected.  Potential
   518 INCOMPATIBILITY -- parse translations need to cope with syntactic
   519 constant "_idtdummy" in the binding position.
   520 
   521 * Syntax: removed obsolete syntactic constant "_K" and its associated
   522 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   523 for example "A -> B" => "Pi A (%_. B)".
   524 
   525 * Pure: 'class_deps' command visualizes the subclass relation, using
   526 the graph browser tool.
   527 
   528 * Pure: 'print_theory' now suppresses entities with internal name
   529 (trailing "_") by default; use '!' option for full details.
   530 
   531 
   532 *** HOL ***
   533 
   534 * Method "algebra" solves polynomial equations over (semi)rings using
   535   Groebner bases. The (semi)ring structure is defined by locales and
   536   the tool setup depends on that generic context. Installing the
   537   method for a specific type involves instantiating the locale and
   538   possibly adding declarations for computation on the coefficients.
   539   The method is already instantiated for natural numbers and for the
   540   axiomatic class of idoms with numerals.  See also the paper by
   541   Chaieb and Wenzel at CALCULEMUS 2007 for the general principles
   542   underlying this architecture of context-aware proof-tools.
   543 
   544 * constant "List.op @" now named "List.append".  Use ML antiquotations
   545 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   546 possible incompatibilities when working on ML level.
   547 
   548 * Constant renames due to introduction of canonical name prefixing for
   549   class package:
   550 
   551     HOL.abs ~> HOL.minus_class.abs
   552     HOL.divide ~> HOL.divide_class.divide
   553     Nat.power ~> Nat.power_class.power
   554     Nat.size ~> Nat.size_class.size
   555     Numeral.number_of ~> Numeral.number_class.number_of
   556     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   557 
   558 * Rudimentary class target mechanism involves constant renames:
   559 
   560     Orderings.min ~> Orderings.ord_class.min
   561     Orderings.max ~> Orderings.ord_class.max
   562     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   563 
   564 * case expressions and primrec: missing cases now mapped to "undefined"
   565 instead of "arbitrary"
   566 
   567 * new constant "undefined" with axiom "undefined x = undefined"
   568 
   569 * new class "default" with associated constant "default"
   570 
   571 * new function listsum :: 'a list => 'a for arbitrary monoids.
   572   Special syntax: "SUM x <- xs. f x" (and latex variants)
   573 
   574 * new (input only) syntax for Haskell-like list comprehension, eg
   575   [(x,y). x <- xs, y <- ys, x ~= y]
   576   For details see List.thy.
   577 
   578 * The special syntax for function "filter" has changed from [x : xs. P] to
   579   [x <- xs. P] to avoid an ambiguity caused by list comprehension syntax,
   580   and for uniformity. INCOMPATIBILITY
   581 
   582 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   583     when generating code.
   584 
   585 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   586     when generating code.
   587 
   588 * Library/Commutative_Ring.thy: switched from recdef to function package;
   589     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   590 
   591 * Some steps towards more uniform lattice theory development in HOL.
   592 
   593     constants "meet" and "join" now named "inf" and "sup"
   594     constant "Meet" now named "Inf"
   595 
   596     classes "meet_semilorder" and "join_semilorder" now named
   597       "lower_semilattice" and "upper_semilattice"
   598     class "lorder" now named "lattice"
   599     class "comp_lat" now named "complete_lattice"
   600 
   601     Instantiation of lattice classes allows explicit definitions
   602     for "inf" and "sup" operations.
   603 
   604   INCOMPATIBILITY.  Theorem renames:
   605 
   606     meet_left_le            ~> inf_le1
   607     meet_right_le           ~> inf_le2
   608     join_left_le            ~> sup_ge1
   609     join_right_le           ~> sup_ge2
   610     meet_join_le            ~> inf_sup_ord
   611     le_meetI                ~> le_infI
   612     join_leI                ~> le_supI
   613     le_meet                 ~> le_inf_iff
   614     le_join                 ~> ge_sup_conv
   615     meet_idempotent         ~> inf_idem
   616     join_idempotent         ~> sup_idem
   617     meet_comm               ~> inf_commute
   618     join_comm               ~> sup_commute
   619     meet_leI1               ~> le_infI1
   620     meet_leI2               ~> le_infI2
   621     le_joinI1               ~> le_supI1
   622     le_joinI2               ~> le_supI2
   623     meet_assoc              ~> inf_assoc
   624     join_assoc              ~> sup_assoc
   625     meet_left_comm          ~> inf_left_commute
   626     meet_left_idempotent    ~> inf_left_idem
   627     join_left_comm          ~> sup_left_commute
   628     join_left_idempotent    ~> sup_left_idem
   629     meet_aci                ~> inf_aci
   630     join_aci                ~> sup_aci
   631     le_def_meet             ~> le_iff_inf
   632     le_def_join             ~> le_iff_sup
   633     join_absorp2            ~> sup_absorb2
   634     join_absorp1            ~> sup_absorb1
   635     meet_absorp1            ~> inf_absorb1
   636     meet_absorp2            ~> inf_absorb2
   637     meet_join_absorp        ~> inf_sup_absorb
   638     join_meet_absorp        ~> sup_inf_absorb
   639     distrib_join_le         ~> distrib_sup_le
   640     distrib_meet_le         ~> distrib_inf_le
   641 
   642     add_meet_distrib_left   ~> add_inf_distrib_left
   643     add_join_distrib_left   ~> add_sup_distrib_left
   644     is_join_neg_meet        ~> is_join_neg_inf
   645     is_meet_neg_join        ~> is_meet_neg_sup
   646     add_meet_distrib_right  ~> add_inf_distrib_right
   647     add_join_distrib_right  ~> add_sup_distrib_right
   648     add_meet_join_distribs  ~> add_sup_inf_distribs
   649     join_eq_neg_meet        ~> sup_eq_neg_inf
   650     meet_eq_neg_join        ~> inf_eq_neg_sup
   651     add_eq_meet_join        ~> add_eq_inf_sup
   652     meet_0_imp_0            ~> inf_0_imp_0
   653     join_0_imp_0            ~> sup_0_imp_0
   654     meet_0_eq_0             ~> inf_0_eq_0
   655     join_0_eq_0             ~> sup_0_eq_0
   656     neg_meet_eq_join        ~> neg_inf_eq_sup
   657     neg_join_eq_meet        ~> neg_sup_eq_inf
   658     join_eq_if              ~> sup_eq_if
   659 
   660     mono_meet               ~> mono_inf
   661     mono_join               ~> mono_sup
   662     meet_bool_eq            ~> inf_bool_eq
   663     join_bool_eq            ~> sup_bool_eq
   664     meet_fun_eq             ~> inf_fun_eq
   665     join_fun_eq             ~> sup_fun_eq
   666     meet_set_eq             ~> inf_set_eq
   667     join_set_eq             ~> sup_set_eq
   668     meet1_iff               ~> inf1_iff
   669     meet2_iff               ~> inf2_iff
   670     meet1I                  ~> inf1I
   671     meet2I                  ~> inf2I
   672     meet1D1                 ~> inf1D1
   673     meet2D1                 ~> inf2D1
   674     meet1D2                 ~> inf1D2
   675     meet2D2                 ~> inf2D2
   676     meet1E                  ~> inf1E
   677     meet2E                  ~> inf2E
   678     join1_iff               ~> sup1_iff
   679     join2_iff               ~> sup2_iff
   680     join1I1                 ~> sup1I1
   681     join2I1                 ~> sup2I1
   682     join1I1                 ~> sup1I1
   683     join2I2                 ~> sup1I2
   684     join1CI                 ~> sup1CI
   685     join2CI                 ~> sup2CI
   686     join1E                  ~> sup1E
   687     join2E                  ~> sup2E
   688 
   689     is_meet_Meet            ~> is_meet_Inf
   690     Meet_bool_def           ~> Inf_bool_def
   691     Meet_fun_def            ~> Inf_fun_def
   692     Meet_greatest           ~> Inf_greatest
   693     Meet_lower              ~> Inf_lower
   694     Meet_set_def            ~> Inf_set_def
   695 
   696     listsp_meetI            ~> listsp_infI
   697     listsp_meet_eq          ~> listsp_inf_eq
   698 
   699     meet_min                ~> inf_min
   700     join_max                ~> sup_max
   701 
   702 * Classes "order" and "linorder": facts "refl", "trans" and
   703 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   704 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   705 
   706 * Classes "order" and "linorder": 
   707 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   708 proofs changed.
   709 
   710 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   711 INCOMPATIBILITY.
   712 
   713 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   714 INCOMPATIBILITY.
   715 
   716 * Added syntactic class "size"; overloaded constant "size" now has
   717 type "'a::size ==> bool"
   718 
   719 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   720 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   721 
   722 * Added method "lexicographic_order" automatically synthesizes
   723 termination relations as lexicographic combinations of size measures
   724 -- 'function' package.
   725 
   726 * HOL/records: generalised field-update to take a function on the
   727 field rather than the new value: r(|A := x|) is translated to A_update
   728 (K x) r The K-combinator that is internally used is called K_record.
   729 INCOMPATIBILITY: Usage of the plain update functions has to be
   730 adapted.
   731  
   732 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   733 0 * x = 0, which are required for a semiring.  Richer structures do
   734 not inherit from semiring_0 anymore, because this property is a
   735 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   736 semiring_0, there is more to prove, but this is mostly trivial.
   737 
   738 * axclass "recpower" was generalized to arbitrary monoids, not just
   739 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   740 commutativity or a semiring property, add the corresponding classes.
   741 
   742 * Unified locale partial_order with class definition (cf. theory
   743 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   744 
   745 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   746 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   747 Isar level, use abbreviations instead.
   748 
   749 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   750 rarely occuring name references (e.g. ``List.op mem.simps'') require
   751 renaming (e.g. ``List.memberl.simps'').
   752 
   753 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   754 INCOMPATIBILITY.
   755 
   756 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
   757 
   758 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   759 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   760 significant changes for setting up numeral syntax for types:
   761 
   762   - new constants Numeral.pred and Numeral.succ instead
   763       of former Numeral.bin_pred and Numeral.bin_succ.
   764   - Use integer operations instead of bin_add, bin_mult and so on.
   765   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   766   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   767 
   768 See HOL/Integ/IntArith.thy for an example setup.
   769 
   770 * New top level command 'normal_form' computes the normal form of a
   771 term that may contain free variables. For example ``normal_form
   772 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   773 suitable for heavy-duty computations because the functions are
   774 compiled to ML first.
   775 
   776 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   777 25 like -->); output depends on the "iff" print_mode, the default is
   778 "A = B" (with priority 50).
   779 
   780 * Renamed constants in HOL.thy and Orderings.thy:
   781     op +   ~> HOL.plus_class.plus
   782     op -   ~> HOL.minus_class.minus
   783     uminus ~> HOL.minus_class.uminus
   784     op *   ~> HOL.times_class.times
   785     op <   ~> Orderings.ord_class.less
   786     op <=  ~> Orderings.ord_class.less_eq
   787 
   788 Adaptions may be required in the following cases:
   789 
   790 a) User-defined constants using any of the names "plus", "minus", "times",
   791 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   792 may go wrong.
   793 INCOMPATIBILITY: use more specific names.
   794 
   795 b) Variables named "plus", "minus", "times", "less", "less_eq"
   796 INCOMPATIBILITY: use more specific names.
   797 
   798 c) Permutative equations (e.g. "a + b = b + a")
   799 Since the change of names also changes the order of terms, permutative
   800 rewrite rules may get applied in a different order. Experience shows that
   801 this is rarely the case (only two adaptions in the whole Isabelle
   802 distribution).
   803 INCOMPATIBILITY: rewrite proofs
   804 
   805 d) ML code directly refering to constant names
   806 This in general only affects hand-written proof tactics, simprocs and so on.
   807 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   808 of const_name ML antiquotations.
   809 
   810 * Relations less (<) and less_eq (<=) are also available on type bool.
   811 Modified syntax to disallow nesting without explicit parentheses,
   812 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   813 
   814 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   815 
   816 * Relation composition operator "op O" now has precedence 75 and binds
   817 stronger than union and intersection. INCOMPATIBILITY.
   818 
   819 * The old set interval syntax "{m..n(}" (and relatives) has been
   820 removed.  Use "{m..<n}" (and relatives) instead.
   821 
   822 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   823 "t = s" to False (by simproc "neq_simproc").  For backward
   824 compatibility this can be disabled by ML "reset use_neq_simproc".
   825 
   826 * "m dvd n" where m and n are numbers is evaluated to True/False by
   827 simp.
   828 
   829 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   830 
   831 * Theorem setsum_mult renamed to setsum_right_distrib.
   832 
   833 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   834 ``rule'' method.
   835 
   836 * Reimplemented methods ``sat'' and ``satx'', with several
   837 improvements: goals no longer need to be stated as "<prems> ==>
   838 False", equivalences (i.e. "=" on type bool) are handled, variable
   839 names of the form "lit_<n>" are no longer reserved, significant
   840 speedup.
   841 
   842 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   843 zChaff is still supported as well.
   844 
   845 * 'inductive' and 'datatype': provide projections of mutual rules,
   846 bundled as foo_bar.inducts;
   847 
   848 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   849 Library.
   850 
   851 * Library: moved theory Accessible_Part to main HOL.
   852 
   853 * Library: added theory Coinductive_List of potentially infinite lists
   854 as greatest fixed-point.
   855 
   856 * Library: added theory AssocList which implements (finite) maps as
   857 association lists.
   858 
   859 * Added proof method ``evaluation'' for efficiently solving a goal
   860 (i.e. a boolean expression) by compiling it to ML. The goal is
   861 "proved" (via an oracle) if it evaluates to True.
   862 
   863 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   864 also when invoked by the simplifier.  This results in the simplifier
   865 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   866 fast_arith_split_limit to 0 to obtain the old behavior.
   867 
   868 * Support for hex (0x20) and binary (0b1001) numerals.
   869 
   870 * New method: reify eqs (t), where eqs are equations for an
   871 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   872 parameter, computes a term s::'b and a list xs::'a list and proves the
   873 theorem I xs s = t. This is also known as reification or quoting. The
   874 resulting theorem is applied to the subgoal to substitute t with I xs
   875 s.  If t is omitted, the subgoal itself is reified.
   876 
   877 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   878 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   879 where f is supposed to be a computable function (in the sense of code
   880 generattion). The method uses reify to compute s and xs as above then
   881 applies corr_thm and uses normalization by evaluation to "prove" f s =
   882 r and finally gets the theorem t = r, which is again applied to the
   883 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   884 
   885 * Reflection: Automatic refification now handels binding, an example
   886 is available in HOL/ex/ReflectionEx.thy
   887 
   888 
   889 *** HOL-Algebra ***
   890 
   891 * Formalisation of ideals and the quotient construction over rings.
   892 
   893 * Order and lattice theory no longer based on records.
   894 INCOMPATIBILITY.
   895 
   896 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   897 greatest_closed.  INCOMPATIBILITY.
   898 
   899 * Method algebra is now set up via an attribute.  For examples see
   900 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   901 of algebraic structures.
   902 
   903 * Renamed theory CRing to Ring.
   904 
   905 
   906 *** HOL-Complex ***
   907 
   908 * Theory Real: new method ferrack implements quantifier elimination
   909 for linear arithmetic over the reals. The quantifier elimination
   910 feature is used only for decision, for compatibility with arith. This
   911 means a goal is either solved or left unchanged, no simplification.
   912 
   913 * Hyperreal: Functions root and sqrt are now defined on negative real
   914 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
   915 Nonnegativity side conditions have been removed from many lemmas, so
   916 that more subgoals may now be solved by simplification; potential
   917 INCOMPATIBILITY.
   918 
   919 * Real: New axiomatic classes formalize real normed vector spaces and
   920 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   921 and norm :: 'a => real.
   922 
   923 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   924 from reals into other types. The overloaded constant Reals :: 'a set
   925 is now defined as range of_real; potential INCOMPATIBILITY.
   926 
   927 * Real: ML code generation is supported now and hence also quickcheck.
   928 Reals are implemented as arbitrary precision rationals.
   929 
   930 * Hyperreal: Several constants that previously worked only for the
   931 reals have been generalized, so they now work over arbitrary vector
   932 spaces. Type annotations may need to be added in some cases; potential
   933 INCOMPATIBILITY.
   934 
   935   Infinitesimal  :: ('a::real_normed_vector) star set
   936   HFinite        :: ('a::real_normed_vector) star set
   937   HInfinite      :: ('a::real_normed_vector) star set
   938   approx         :: ('a::real_normed_vector) star => 'a star => bool
   939   monad          :: ('a::real_normed_vector) star => 'a star set
   940   galaxy         :: ('a::real_normed_vector) star => 'a star set
   941   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
   942   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   943   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   944   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   945   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   946   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   947   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   948   sgn            :: 'a::real_normed_vector => 'a
   949   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
   950 
   951 * Complex: Some complex-specific constants are now abbreviations for
   952 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   953 hnorm.  Other constants have been entirely removed in favor of the
   954 polymorphic versions (INCOMPATIBILITY):
   955 
   956   approx        <-- capprox
   957   HFinite       <-- CFinite
   958   HInfinite     <-- CInfinite
   959   Infinitesimal <-- CInfinitesimal
   960   monad         <-- cmonad
   961   galaxy        <-- cgalaxy
   962   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   963   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   964   (ns)deriv     <-- (ns)cderiv
   965 
   966 
   967 *** ML ***
   968 
   969 * Generic arithmetic modules: Tools/integer.ML, Tools/rat.ML, Tools/float.ML
   970 
   971 * Context data interfaces (Theory/Proof/GenericDataFun): removed
   972 name/print, uninitialized data defaults to ad-hoc copy of empty value,
   973 init only required for impure data.  INCOMPATIBILITY: empty really
   974 need to be empty (no dependencies on theory content!)
   975 
   976 * ML within Isar: antiquotations allow to embed statically-checked
   977 formal entities in the source, referring to the context available at
   978 compile-time.  For example:
   979 
   980 ML {* @{typ "'a => 'b"} *}
   981 ML {* @{term "%x. x"} *}
   982 ML {* @{prop "x == y"} *}
   983 ML {* @{ctyp "'a => 'b"} *}
   984 ML {* @{cterm "%x. x"} *}
   985 ML {* @{cprop "x == y"} *}
   986 ML {* @{thm asm_rl} *}
   987 ML {* @{thms asm_rl} *}
   988 ML {* @{const_name c} *}
   989 ML {* @{const_syntax c} *}
   990 ML {* @{context} *}
   991 ML {* @{theory} *}
   992 ML {* @{theory Pure} *}
   993 ML {* @{simpset} *}
   994 ML {* @{claset} *}
   995 ML {* @{clasimpset} *}
   996 
   997 The same works for sources being ``used'' within an Isar context.
   998 
   999 * ML in Isar: improved error reporting; extra verbosity with
  1000 Toplevel.debug enabled.
  1001 
  1002 * Pure/library:
  1003 
  1004   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1005   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1006 
  1007 The semantics of "burrow" is: "take a function with *simulatanously*
  1008 transforms a list of value, and apply it *simulatanously* to a list of
  1009 list of values of the appropriate type". Compare this with "map" which
  1010 would *not* apply its argument function simulatanously but in
  1011 sequence; "fold_burrow" has an additional context.
  1012 
  1013 * Pure/library: functions map2 and fold2 with curried syntax for
  1014 simultanous mapping and folding:
  1015 
  1016     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1017     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1018 
  1019 * Pure/library: indexed lists - some functions in the Isabelle library
  1020 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1021 given more convenient names and signatures reminiscent of similar
  1022 functions for alists, tables, etc:
  1023 
  1024   val nth: 'a list -> int -> 'a 
  1025   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1026   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1027 
  1028 Note that fold_index starts counting at index 0, not 1 like foldln
  1029 used to.
  1030 
  1031 * Pure/library: added general ``divide_and_conquer'' combinator on
  1032 lists.
  1033 
  1034 * Pure/General/table.ML: the join operations now works via exceptions
  1035 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1036 admits slightly more efficient complex applications.
  1037 
  1038 * Pure: datatype Context.generic joins theory/Proof.context and
  1039 provides some facilities for code that works in either kind of
  1040 context, notably GenericDataFun for uniform theory and proof data.
  1041 
  1042 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1043 use Context.generic instead of just theory.
  1044 
  1045 * Pure: simplified internal attribute type, which is now always
  1046 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1047 vs. local (Proof.context) attributes have been discontinued, while
  1048 minimizing code duplication.  Thm.rule_attribute and
  1049 Thm.declaration_attribute build canonical attributes; see also
  1050 structure Context for further operations on Context.generic, notably
  1051 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1052 declarations and definitions.
  1053 
  1054 * Pure/kernel: consts certification ignores sort constraints given in
  1055 signature declarations.  (This information is not relevant to the
  1056 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1057 potential INCOMPATIBILITY.
  1058 
  1059 * Pure: axiomatic type classes are now purely definitional, with
  1060 explicit proofs of class axioms and super class relations performed
  1061 internally.  See Pure/axclass.ML for the main internal interfaces --
  1062 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1063 AxClass.axiomatize_class/classrel/arity supercede
  1064 Sign.add_classes/classrel/arities.
  1065 
  1066 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1067 global/local versions on theory vs. Proof.context have been
  1068 discontinued; Attrib.syntax and Method.syntax have been adapted
  1069 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1070 attributes, methods, etc.
  1071 
  1072 * Pure: several functions of signature "... -> theory -> theory * ..."
  1073 have been reoriented to "... -> theory -> ... * theory" in order to
  1074 allow natural usage in combination with the ||>, ||>>, |-> and
  1075 fold_map combinators.
  1076 
  1077 * Pure: official theorem names (closed derivations) and additional
  1078 comments (tags) are now strictly separate.  Name hints -- which are
  1079 maintained as tags -- may be attached any time without affecting the
  1080 derivation.
  1081 
  1082 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1083 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1084 achieve the old behaviour.
  1085 
  1086 * Pure: the "Goal" constant is now called "prop", supporting a
  1087 slightly more general idea of ``protecting'' meta-level rule
  1088 statements.
  1089 
  1090 * Pure: Logic.(un)varify only works in a global context, which is now
  1091 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1092 Logic.legacy_(un)varify as temporary workaround.
  1093 
  1094 * Pure: structure Name provides scalable operations for generating
  1095 internal variable names, notably Name.variants etc.  This replaces
  1096 some popular functions from term.ML:
  1097 
  1098   Term.variant		->  Name.variant
  1099   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1100   Term.invent_names	->  Name.invent_list
  1101 
  1102 Note that low-level renaming rarely occurs in new code -- operations
  1103 from structure Variable are used instead (see below).
  1104 
  1105 * Pure: structure Variable provides fundamental operations for proper
  1106 treatment of fixed/schematic variables in a context.  For example,
  1107 Variable.import introduces fixes for schematics of given facts and
  1108 Variable.export reverses the effect (up to renaming) -- this replaces
  1109 various freeze_thaw operations.
  1110 
  1111 * Pure: structure Goal provides simple interfaces for
  1112 init/conclude/finish and tactical prove operations (replacing former
  1113 Tactic.prove).  Goal.prove is the canonical way to prove results
  1114 within a given context; Goal.prove_global is a degraded version for
  1115 theory level goals, including a global Drule.standard.  Note that
  1116 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1117 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1118 in a locale context).
  1119 
  1120 * Isar: simplified treatment of user-level errors, using exception
  1121 ERROR of string uniformly.  Function error now merely raises ERROR,
  1122 without any side effect on output channels.  The Isar toplevel takes
  1123 care of proper display of ERROR exceptions.  ML code may use plain
  1124 handle/can/try; cat_error may be used to concatenate errors like this:
  1125 
  1126   ... handle ERROR msg => cat_error msg "..."
  1127 
  1128 Toplevel ML code (run directly or through the Isar toplevel) may be
  1129 embedded into the Isar toplevel with exception display/debug like
  1130 this:
  1131 
  1132   Isar.toplevel (fn () => ...)
  1133 
  1134 INCOMPATIBILITY, removed special transform_error facilities, removed
  1135 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1136 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1137 -- use plain ERROR instead.
  1138 
  1139 * Isar: theory setup now has type (theory -> theory), instead of a
  1140 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1141 
  1142 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1143 subject to ProofContext.debug/verbose flags.
  1144 
  1145 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1146 theory before entering a proof state.  Transactions now always see a
  1147 quasi-functional intermediate checkpoint, both in interactive and
  1148 batch mode.
  1149 
  1150 * Simplifier: the simpset of a running simplification process now
  1151 contains a proof context (cf. Simplifier.the_context), which is the
  1152 very context that the initial simpset has been retrieved from (by
  1153 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1154 (solver, looper etc.) may depend on arbitrary proof data.
  1155 
  1156 * Simplifier.inherit_context inherits the proof context (plus the
  1157 local bounds) of the current simplification process; any simproc
  1158 etc. that calls the Simplifier recursively should do this!  Removed
  1159 former Simplifier.inherit_bounds, which is already included here --
  1160 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1161 specify an explicit context using Simplifier.context/theory_context.
  1162 
  1163 * Simplifier/Classical Reasoner: more abstract interfaces
  1164 change_simpset/claset for modifying the simpset/claset reference of a
  1165 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1166 INCOMPATIBILITY.
  1167 
  1168 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1169 "Trueprop" etc.
  1170 
  1171 
  1172 *** System ***
  1173 
  1174 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1175 locations -- now includes the Isabelle version identifier as well.
  1176 This simplifies use of multiple Isabelle installations.
  1177 
  1178 * isabelle-process: option -S (secure mode) disables some critical
  1179 operations, notably runtime compilation and evaluation of ML source
  1180 code.
  1181 
  1182 
  1183 New in Isabelle2005 (October 2005)
  1184 ----------------------------------
  1185 
  1186 *** General ***
  1187 
  1188 * Theory headers: the new header syntax for Isar theories is
  1189 
  1190   theory <name>
  1191   imports <theory1> ... <theoryN>
  1192   uses <file1> ... <fileM>
  1193   begin
  1194 
  1195 where the 'uses' part is optional.  The previous syntax
  1196 
  1197   theory <name> = <theory1> + ... + <theoryN>:
  1198 
  1199 will disappear in the next release.  Use isatool fixheaders to convert
  1200 existing theory files.  Note that there is no change in ancient
  1201 non-Isar theories now, but these will disappear soon.
  1202 
  1203 * Theory loader: parent theories can now also be referred to via
  1204 relative and absolute paths.
  1205 
  1206 * Command 'find_theorems' searches for a list of criteria instead of a
  1207 list of constants. Known criteria are: intro, elim, dest, name:string,
  1208 simp:term, and any term. Criteria can be preceded by '-' to select
  1209 theorems that do not match. Intro, elim, dest select theorems that
  1210 match the current goal, name:s selects theorems whose fully qualified
  1211 name contain s, and simp:term selects all simplification rules whose
  1212 lhs match term.  Any other term is interpreted as pattern and selects
  1213 all theorems matching the pattern. Available in ProofGeneral under
  1214 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1215 
  1216   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1217 
  1218 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1219 matching the current goal as introduction rule and not having "HOL."
  1220 in their name (i.e. not being defined in theory HOL).
  1221 
  1222 * Command 'thms_containing' has been discontinued in favour of
  1223 'find_theorems'; INCOMPATIBILITY.
  1224 
  1225 * Communication with Proof General is now 8bit clean, which means that
  1226 Unicode text in UTF-8 encoding may be used within theory texts (both
  1227 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1228 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1229 
  1230   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1231   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1232 
  1233 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1234 Classical Reasoner.  Typical big applications run around 2 times
  1235 faster.
  1236 
  1237 
  1238 *** Document preparation ***
  1239 
  1240 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1241 of raw sources.  Only those symbols that do not require additional
  1242 LaTeX packages (depending on comments in isabellesym.sty) are
  1243 displayed properly, everything else is left verbatim.  isatool display
  1244 and isatool print are used as front ends (these are subject to the
  1245 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1246 
  1247 * Command tags control specific markup of certain regions of text,
  1248 notably folding and hiding.  Predefined tags include "theory" (for
  1249 theory begin and end), "proof" for proof commands, and "ML" for
  1250 commands involving ML code; the additional tags "visible" and
  1251 "invisible" are unused by default.  Users may give explicit tag
  1252 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1253 interpretation of tags is determined by the LaTeX job during document
  1254 preparation: see option -V of isatool usedir, or options -n and -t of
  1255 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1256 \isadroptag.
  1257 
  1258 Several document versions may be produced at the same time via isatool
  1259 usedir (the generated index.html will link all of them).  Typical
  1260 specifications include ''-V document=theory,proof,ML'' to present
  1261 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1262 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1263 these parts without any formal replacement text.  The Isabelle site
  1264 default settings produce ''document'' and ''outline'' versions as
  1265 specified above.
  1266 
  1267 * Several new antiquotations:
  1268 
  1269   @{term_type term} prints a term with its type annotated;
  1270 
  1271   @{typeof term} prints the type of a term;
  1272 
  1273   @{const const} is the same as @{term const}, but checks that the
  1274   argument is a known logical constant;
  1275 
  1276   @{term_style style term} and @{thm_style style thm} print a term or
  1277   theorem applying a "style" to it
  1278 
  1279   @{ML text}
  1280 
  1281 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1282 definitions, equations, inequations etc., 'concl' printing only the
  1283 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1284 to print the specified premise.  TermStyle.add_style provides an ML
  1285 interface for introducing further styles.  See also the "LaTeX Sugar"
  1286 document practical applications.  The ML antiquotation prints
  1287 type-checked ML expressions verbatim.
  1288 
  1289 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1290 and 'text' support optional locale specification '(in loc)', which
  1291 specifies the default context for interpreting antiquotations.  For
  1292 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1293 
  1294 * Option 'locale=NAME' of antiquotations specifies an alternative
  1295 context interpreting the subsequent argument.  For example: @{thm
  1296 [locale=lattice] inf_assoc}.
  1297 
  1298 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1299 a proof context.
  1300 
  1301 * Proper output of antiquotations for theory commands involving a
  1302 proof context (such as 'locale' or 'theorem (in loc) ...').
  1303 
  1304 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1305 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1306 
  1307 * isatool usedir: new option -C (default true) controls whether option
  1308 -D should include a copy of the original document directory; -C false
  1309 prevents unwanted effects such as copying of administrative CVS data.
  1310 
  1311 
  1312 *** Pure ***
  1313 
  1314 * Considerably improved version of 'constdefs' command.  Now performs
  1315 automatic type-inference of declared constants; additional support for
  1316 local structure declarations (cf. locales and HOL records), see also
  1317 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1318 sequential dependencies of definitions within a single 'constdefs'
  1319 section; moreover, the declared name needs to be an identifier.  If
  1320 all fails, consider to fall back on 'consts' and 'defs' separately.
  1321 
  1322 * Improved indexed syntax and implicit structures.  First of all,
  1323 indexed syntax provides a notational device for subscripted
  1324 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1325 expressions.  Secondly, in a local context with structure
  1326 declarations, number indexes \<^sub>n or the empty index (default
  1327 number 1) refer to a certain fixed variable implicitly; option
  1328 show_structs controls printing of implicit structures.  Typical
  1329 applications of these concepts involve record types and locales.
  1330 
  1331 * New command 'no_syntax' removes grammar declarations (and
  1332 translations) resulting from the given syntax specification, which is
  1333 interpreted in the same manner as for the 'syntax' command.
  1334 
  1335 * 'Advanced' translation functions (parse_translation etc.) may depend
  1336 on the signature of the theory context being presently used for
  1337 parsing/printing, see also isar-ref manual.
  1338 
  1339 * Improved 'oracle' command provides a type-safe interface to turn an
  1340 ML expression of type theory -> T -> term into a primitive rule of
  1341 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1342 is already included here); see also FOL/ex/IffExample.thy;
  1343 INCOMPATIBILITY.
  1344 
  1345 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1346 before); "cI" is no longer bound, use "c.intro" instead.
  1347 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1348 axclasses vs. locales.
  1349 
  1350 * Improved internal renaming of symbolic identifiers -- attach primes
  1351 instead of base 26 numbers.
  1352 
  1353 * New flag show_question_marks controls printing of leading question
  1354 marks in schematic variable names.
  1355 
  1356 * In schematic variable names, *any* symbol following \<^isub> or
  1357 \<^isup> is now treated as part of the base name.  For example, the
  1358 following works without printing of awkward ".0" indexes:
  1359 
  1360   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1361     by simp
  1362 
  1363 * Inner syntax includes (*(*nested*) comments*).
  1364 
  1365 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1366 annotations as "(00...)".
  1367 
  1368 * Clear separation of logical types and nonterminals, where the latter
  1369 may only occur in 'syntax' specifications or type abbreviations.
  1370 Before that distinction was only partially implemented via type class
  1371 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1372 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1373 exotic syntax specifications may require further adaption
  1374 (e.g. Cube/Cube.thy).
  1375 
  1376 * Removed obsolete type class "logic", use the top sort {} instead.
  1377 Note that non-logical types should be declared as 'nonterminals'
  1378 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1379 specifications.
  1380 
  1381 * Attributes 'induct' and 'cases': type or set names may now be
  1382 locally fixed variables as well.
  1383 
  1384 * Simplifier: can now control the depth to which conditional rewriting
  1385 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1386 Limit.
  1387 
  1388 * Simplifier: simplification procedures may now take the current
  1389 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1390 interface), which is very useful for calling the Simplifier
  1391 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1392 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1393 low-level mk_simproc no longer applies Logic.varify internally, to
  1394 allow for use in a context of fixed variables.
  1395 
  1396 * thin_tac now works even if the assumption being deleted contains !!
  1397 or ==>.  More generally, erule now works even if the major premise of
  1398 the elimination rule contains !! or ==>.
  1399 
  1400 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1401 
  1402 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1403 from Pure, which contains all common declarations already.  Both
  1404 theories are defined via plain Isabelle/Isar .thy files.
  1405 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1406 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1407 use isatool fixcpure to adapt your theory and ML sources.
  1408 
  1409 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1410 selections of theorems in named facts via index ranges.
  1411 
  1412 * 'print_theorems': in theory mode, really print the difference
  1413 wrt. the last state (works for interactive theory development only),
  1414 in proof mode print all local facts (cf. 'print_facts');
  1415 
  1416 * 'hide': option '(open)' hides only base names.
  1417 
  1418 * More efficient treatment of intermediate checkpoints in interactive
  1419 theory development.
  1420 
  1421 * Code generator is now invoked via code_module (incremental code
  1422 generation) and code_library (modular code generation, ML structures
  1423 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1424 must be quoted when used as identifiers.
  1425 
  1426 * New 'value' command for reading, evaluating and printing terms using
  1427 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1428 quoted when used as identifier.
  1429 
  1430 
  1431 *** Locales ***
  1432 
  1433 * New commands for the interpretation of locale expressions in
  1434 theories (1), locales (2) and proof contexts (3).  These generate
  1435 proof obligations from the expression specification.  After the
  1436 obligations have been discharged, theorems of the expression are added
  1437 to the theory, target locale or proof context.  The synopsis of the
  1438 commands is a follows:
  1439 
  1440   (1) interpretation expr inst
  1441   (2) interpretation target < expr
  1442   (3) interpret expr inst
  1443 
  1444 Interpretation in theories and proof contexts require a parameter
  1445 instantiation of terms from the current context.  This is applied to
  1446 specifications and theorems of the interpreted expression.
  1447 Interpretation in locales only permits parameter renaming through the
  1448 locale expression.  Interpretation is smart in that interpretations
  1449 that are active already do not occur in proof obligations, neither are
  1450 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1451 inspect active interpretations of a particular locale.  For details,
  1452 see the Isar Reference manual.  Examples can be found in
  1453 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1454 
  1455 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1456 'interpret' instead.
  1457 
  1458 * New context element 'constrains' for adding type constraints to
  1459 parameters.
  1460 
  1461 * Context expressions: renaming of parameters with syntax
  1462 redeclaration.
  1463 
  1464 * Locale declaration: 'includes' disallowed.
  1465 
  1466 * Proper static binding of attribute syntax -- i.e. types / terms /
  1467 facts mentioned as arguments are always those of the locale definition
  1468 context, independently of the context of later invocations.  Moreover,
  1469 locale operations (renaming and type / term instantiation) are applied
  1470 to attribute arguments as expected.
  1471 
  1472 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1473 actual attributes; rare situations may require Attrib.attribute to
  1474 embed those attributes into Attrib.src that lack concrete syntax.
  1475 Attribute implementations need to cooperate properly with the static
  1476 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1477 Attrib.XXX_thm etc. already do the right thing without further
  1478 intervention.  Only unusual applications -- such as "where" or "of"
  1479 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1480 on the context and the facts involved -- may have to assign parsed
  1481 values to argument tokens explicitly.
  1482 
  1483 * Changed parameter management in theorem generation for long goal
  1484 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1485 theorem statement in rare situations.
  1486 
  1487 * Locale inspection command 'print_locale' omits notes elements.  Use
  1488 'print_locale!' to have them included in the output.
  1489 
  1490 
  1491 *** Provers ***
  1492 
  1493 * Provers/hypsubst.ML: improved version of the subst method, for
  1494 single-step rewriting: it now works in bound variable contexts. New is
  1495 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1496 rewrite a different subterm than the original subst method, which is
  1497 still available as 'simplesubst'.
  1498 
  1499 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1500 and quasi orders.
  1501 
  1502 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1503 reflexive-transitive closure of relations.
  1504 
  1505 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1506 limit (previously hard-coded with a value of 20) user-definable.
  1507 
  1508 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1509 is peformed already.  Object-logics merely need to finish their
  1510 initial simpset configuration as before.  INCOMPATIBILITY.
  1511 
  1512 
  1513 *** HOL ***
  1514 
  1515 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1516 
  1517   syntax (epsilon)
  1518     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1519 
  1520 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1521 and x-symbol; use option '-m epsilon' to get it actually printed.
  1522 Moreover, the mathematically important symbolic identifier \<epsilon>
  1523 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1524 
  1525 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1526 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1527 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1528 support corresponding Isar calculations.
  1529 
  1530 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1531 instead of ":".
  1532 
  1533 * theory SetInterval: changed the syntax for open intervals:
  1534 
  1535   Old       New
  1536   {..n(}    {..<n}
  1537   {)n..}    {n<..}
  1538   {m..n(}   {m..<n}
  1539   {)m..n}   {m<..n}
  1540   {)m..n(}  {m<..<n}
  1541 
  1542 The old syntax is still supported but will disappear in the next
  1543 release.  For conversion use the following Emacs search and replace
  1544 patterns (these are not perfect but work quite well):
  1545 
  1546   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1547   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1548 
  1549 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1550 equalities in commutative rings; method 'algebra' provides a generic
  1551 interface.
  1552 
  1553 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1554 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1555 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1556 be a tuple pattern.
  1557 
  1558 Some new syntax forms are available:
  1559 
  1560   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1561   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1562   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1563   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1564 
  1565 The latter form "\<Sum>x < k. e" used to be based on a separate
  1566 function "Summation", which has been discontinued.
  1567 
  1568 * theory Finite_Set: in structured induction proofs, the insert case
  1569 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1570 (insert F x)'.
  1571 
  1572 * The 'refute' command has been extended to support a much larger
  1573 fragment of HOL, including axiomatic type classes, constdefs and
  1574 typedefs, inductive datatypes and recursion.
  1575 
  1576 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1577 Requires zChaff with proof generation to be installed.  See
  1578 HOL/ex/SAT_Examples.thy for examples.
  1579 
  1580 * Datatype induction via method 'induct' now preserves the name of the
  1581 induction variable. For example, when proving P(xs::'a list) by
  1582 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1583 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1584 in unstructured proof scripts.
  1585 
  1586 * Reworked implementation of records.  Improved scalability for
  1587 records with many fields, avoiding performance problems for type
  1588 inference. Records are no longer composed of nested field types, but
  1589 of nested extension types. Therefore the record type only grows linear
  1590 in the number of extensions and not in the number of fields.  The
  1591 top-level (users) view on records is preserved.  Potential
  1592 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1593 old record representation. The type generated for a record is called
  1594 <record_name>_ext_type.
  1595 
  1596 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1597 proofs triggered by a record definition or a simproc (if
  1598 quick_and_dirty is enabled).  Definitions of large records can take
  1599 quite long.
  1600 
  1601 New simproc record_upd_simproc for simplification of multiple record
  1602 updates enabled by default.  Moreover, trivial updates are also
  1603 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1604 occasionally, since simplification is more powerful by default.
  1605 
  1606 * typedef: proper support for polymorphic sets, which contain extra
  1607 type-variables in the term.
  1608 
  1609 * Simplifier: automatically reasons about transitivity chains
  1610 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1611 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1612 old proofs break occasionally as simplification may now solve more
  1613 goals than previously.
  1614 
  1615 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1616 present.  Works for all partial orders (class "order"), in particular
  1617 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1618 just like y <= x.
  1619 
  1620 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1621 bound variable or a constant then the let is unfolded.  Otherwise
  1622 first a is simplified to b, and then f b is simplified to g. If
  1623 possible we abstract b from g arriving at "let x = b in h x",
  1624 otherwise we unfold the let and arrive at g.  The simproc can be
  1625 enabled/disabled by the reference use_let_simproc.  Potential
  1626 INCOMPATIBILITY since simplification is more powerful by default.
  1627 
  1628 * Classical reasoning: the meson method now accepts theorems as arguments.
  1629 
  1630 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1631 jobs to provide advice on the provability of subgoals.
  1632 
  1633 * Theory OrderedGroup and Ring_and_Field: various additions and
  1634 improvements to faciliate calculations involving equalities and
  1635 inequalities.
  1636 
  1637 The following theorems have been eliminated or modified
  1638 (INCOMPATIBILITY):
  1639 
  1640   abs_eq             now named abs_of_nonneg
  1641   abs_of_ge_0        now named abs_of_nonneg
  1642   abs_minus_eq       now named abs_of_nonpos
  1643   imp_abs_id         now named abs_of_nonneg
  1644   imp_abs_neg_id     now named abs_of_nonpos
  1645   mult_pos           now named mult_pos_pos
  1646   mult_pos_le        now named mult_nonneg_nonneg
  1647   mult_pos_neg_le    now named mult_nonneg_nonpos
  1648   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1649   mult_neg           now named mult_neg_neg
  1650   mult_neg_le        now named mult_nonpos_nonpos
  1651 
  1652 * Theory Parity: added rules for simplifying exponents.
  1653 
  1654 * Theory List:
  1655 
  1656 The following theorems have been eliminated or modified
  1657 (INCOMPATIBILITY):
  1658 
  1659   list_all_Nil       now named list_all.simps(1)
  1660   list_all_Cons      now named list_all.simps(2)
  1661   list_all_conv      now named list_all_iff
  1662   set_mem_eq         now named mem_iff
  1663 
  1664 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1665 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1666 
  1667 
  1668 *** HOL-Complex ***
  1669 
  1670 * Theory RealDef: better support for embedding natural numbers and
  1671 integers in the reals.
  1672 
  1673 The following theorems have been eliminated or modified
  1674 (INCOMPATIBILITY):
  1675 
  1676   exp_ge_add_one_self  now requires no hypotheses
  1677   real_of_int_add      reversed direction of equality (use [symmetric])
  1678   real_of_int_minus    reversed direction of equality (use [symmetric])
  1679   real_of_int_diff     reversed direction of equality (use [symmetric])
  1680   real_of_int_mult     reversed direction of equality (use [symmetric])
  1681 
  1682 * Theory RComplete: expanded support for floor and ceiling functions.
  1683 
  1684 * Theory Ln is new, with properties of the natural logarithm
  1685 
  1686 * Hyperreal: There is a new type constructor "star" for making
  1687 nonstandard types.  The old type names are now type synonyms:
  1688 
  1689   hypreal = real star
  1690   hypnat = nat star
  1691   hcomplex = complex star
  1692 
  1693 * Hyperreal: Many groups of similarly-defined constants have been
  1694 replaced by polymorphic versions (INCOMPATIBILITY):
  1695 
  1696   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1697 
  1698   starset      <-- starsetNat, starsetC
  1699   *s*          <-- *sNat*, *sc*
  1700   starset_n    <-- starsetNat_n, starsetC_n
  1701   *sn*         <-- *sNatn*, *scn*
  1702   InternalSets <-- InternalNatSets, InternalCSets
  1703 
  1704   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1705   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1706   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1707   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1708   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1709 
  1710 * Hyperreal: Many type-specific theorems have been removed in favor of
  1711 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1712 
  1713   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1714   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1715   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1716   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1717   right_minus <-- hypreal_add_minus
  1718   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1719   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1720   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1721   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1722   mult_1_right <-- hcomplex_mult_one_right
  1723   mult_zero_left <-- hcomplex_mult_zero_left
  1724   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1725   right_distrib <-- hypnat_add_mult_distrib2
  1726   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1727   right_inverse <-- hypreal_mult_inverse
  1728   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1729   order_refl <-- {hypreal,hypnat}_le_refl
  1730   order_trans <-- {hypreal,hypnat}_le_trans
  1731   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1732   order_less_le <-- {hypreal,hypnat}_less_le
  1733   linorder_linear <-- {hypreal,hypnat}_le_linear
  1734   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1735   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1736   add_nonneg_nonneg <-- hypreal_le_add_order
  1737 
  1738 * Hyperreal: Separate theorems having to do with type-specific
  1739 versions of constants have been merged into theorems that apply to the
  1740 new polymorphic constants (INCOMPATIBILITY):
  1741 
  1742   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1743   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1744   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1745   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1746   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1747   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1748   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1749   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1750   STAR_diff <-- {STAR,STARC}_diff
  1751   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1752     STARC_hcomplex_of_complex}_image_subset
  1753   starset_n_Un <-- starset{Nat,C}_n_Un
  1754   starset_n_Int <-- starset{Nat,C}_n_Int
  1755   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1756   starset_n_diff <-- starset{Nat,C}_n_diff
  1757   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1758   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1759   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1760   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1761   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1762   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1763   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1764   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1765   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1766   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1767   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1768   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1769   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1770   starfun_diff <-- starfun{C,RC,CR}_diff
  1771   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1772   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1773   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1774   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1775   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1776   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1777   starfun_Id <-- starfunC_Id
  1778   starfun_approx <-- starfun{Nat,CR}_approx
  1779   starfun_capprox <-- starfun{C,RC}_capprox
  1780   starfun_abs <-- starfunNat_rabs
  1781   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1782   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1783   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1784   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1785   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1786   starfun_add_approx <-- starfunCR_add_approx
  1787   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1788   starfun_divide <-- starfun{C,CR,RC}_divide
  1789   starfun_n <-- starfun{Nat,C}_n
  1790   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1791   starfun_n_add <-- starfun{Nat,C}_n_add
  1792   starfun_n_add_minus <-- starfunNat_n_add_minus
  1793   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1794   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1795   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1796 
  1797   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1798   star_n_minus <-- {hypreal,hcomplex}_minus
  1799   star_n_diff <-- {hypreal,hcomplex}_diff
  1800   star_n_mult <-- {hypreal,hcomplex}_mult
  1801   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1802   star_n_le <-- {hypreal,hypnat}_le
  1803   star_n_less <-- {hypreal,hypnat}_less
  1804   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1805   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1806   star_n_abs <-- hypreal_hrabs
  1807   star_n_divide <-- hcomplex_divide
  1808 
  1809   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1810   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1811   star_of_diff <-- hypreal_of_real_diff
  1812   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1813   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1814   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1815   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1816   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1817   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1818   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1819   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1820   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1821   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1822   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1823   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1824   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1825   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1826   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1827   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1828   star_of_power <-- hypreal_of_real_power
  1829   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1830 
  1831 * Hyperreal: new method "transfer" that implements the transfer
  1832 principle of nonstandard analysis. With a subgoal that mentions
  1833 nonstandard types like "'a star", the command "apply transfer"
  1834 replaces it with an equivalent one that mentions only standard types.
  1835 To be successful, all free variables must have standard types; non-
  1836 standard variables must have explicit universal quantifiers.
  1837 
  1838 * Hyperreal: A theory of Taylor series.
  1839 
  1840 
  1841 *** HOLCF ***
  1842 
  1843 * Discontinued special version of 'constdefs' (which used to support
  1844 continuous functions) in favor of the general Pure one with full
  1845 type-inference.
  1846 
  1847 * New simplification procedure for solving continuity conditions; it
  1848 is much faster on terms with many nested lambda abstractions (cubic
  1849 instead of exponential time).
  1850 
  1851 * New syntax for domain package: selector names are now optional.
  1852 Parentheses should be omitted unless argument is lazy, for example:
  1853 
  1854   domain 'a stream = cons "'a" (lazy "'a stream")
  1855 
  1856 * New command 'fixrec' for defining recursive functions with pattern
  1857 matching; defining multiple functions with mutual recursion is also
  1858 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1859 sinr, or any data constructor defined by the domain package. The given
  1860 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1861 syntax and examples.
  1862 
  1863 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1864 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1865 but the proof obligation additionally includes an admissibility
  1866 requirement. The packages generate instances of class cpo or pcpo,
  1867 with continuity and strictness theorems for Rep and Abs.
  1868 
  1869 * HOLCF: Many theorems have been renamed according to a more standard naming
  1870 scheme (INCOMPATIBILITY):
  1871 
  1872   foo_inject:  "foo$x = foo$y ==> x = y"
  1873   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1874   foo_less:    "(foo$x << foo$y) = (x << y)"
  1875   foo_strict:  "foo$UU = UU"
  1876   foo_defined: "... ==> foo$x ~= UU"
  1877   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1878 
  1879 
  1880 *** ZF ***
  1881 
  1882 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1883 including the First Isomorphism Theorem (on quotienting by the kernel
  1884 of a homomorphism).
  1885 
  1886 * ZF/Simplifier: install second copy of type solver that actually
  1887 makes use of TC rules declared to Isar proof contexts (or locales);
  1888 the old version is still required for ML proof scripts.
  1889 
  1890 
  1891 *** Cube ***
  1892 
  1893 * Converted to Isar theory format; use locales instead of axiomatic
  1894 theories.
  1895 
  1896 
  1897 *** ML ***
  1898 
  1899 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1900 for ||>, ||>>, |>>,
  1901 
  1902 * Pure/library.ML no longer defines its own option datatype, but uses
  1903 that of the SML basis, which has constructors NONE and SOME instead of
  1904 None and Some, as well as exception Option.Option instead of OPTION.
  1905 The functions the, if_none, is_some, is_none have been adapted
  1906 accordingly, while Option.map replaces apsome.
  1907 
  1908 * Pure/library.ML: the exception LIST has been given up in favour of
  1909 the standard exceptions Empty and Subscript, as well as
  1910 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1911 superceded by the standard hd and tl functions etc.
  1912 
  1913 A number of basic list functions are no longer exported to the ML
  1914 toplevel, as they are variants of predefined functions.  The following
  1915 suggests how one can translate existing code:
  1916 
  1917     rev_append xs ys = List.revAppend (xs, ys)
  1918     nth_elem (i, xs) = List.nth (xs, i)
  1919     last_elem xs = List.last xs
  1920     flat xss = List.concat xss
  1921     seq fs = List.app fs
  1922     partition P xs = List.partition P xs
  1923     mapfilter f xs = List.mapPartial f xs
  1924 
  1925 * Pure/library.ML: several combinators for linear functional
  1926 transformations, notably reverse application and composition:
  1927 
  1928   x |> f                f #> g
  1929   (x, y) |-> f          f #-> g
  1930 
  1931 * Pure/library.ML: introduced/changed precedence of infix operators:
  1932 
  1933   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1934   infix 2 ?;
  1935   infix 3 o oo ooo oooo;
  1936   infix 4 ~~ upto downto;
  1937 
  1938 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1939 infix operators.
  1940 
  1941 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1942 fold_map support linear functional transformations and nesting.  For
  1943 example:
  1944 
  1945   fold f [x1, ..., xN] y =
  1946     y |> f x1 |> ... |> f xN
  1947 
  1948   (fold o fold) f [xs1, ..., xsN] y =
  1949     y |> fold f xs1 |> ... |> fold f xsN
  1950 
  1951   fold f [x1, ..., xN] =
  1952     f x1 #> ... #> f xN
  1953 
  1954   (fold o fold) f [xs1, ..., xsN] =
  1955     fold f xs1 #> ... #> fold f xsN
  1956 
  1957 * Pure/library.ML: the following selectors on type 'a option are
  1958 available:
  1959 
  1960   the:               'a option -> 'a  (*partial*)
  1961   these:             'a option -> 'a  where 'a = 'b list
  1962   the_default: 'a -> 'a option -> 'a
  1963   the_list:          'a option -> 'a list
  1964 
  1965 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1966 basic operations for association lists, following natural argument
  1967 order; moreover the explicit equality predicate passed here avoids
  1968 potentially expensive polymorphic runtime equality checks.
  1969 The old functions may be expressed as follows:
  1970 
  1971   assoc = uncurry (AList.lookup (op =))
  1972   assocs = these oo AList.lookup (op =)
  1973   overwrite = uncurry (AList.update (op =)) o swap
  1974 
  1975 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1976 
  1977   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1978   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1979 
  1980 replacing make_keylist and keyfilter (occassionally used)
  1981 Naive rewrites:
  1982 
  1983   make_keylist = AList.make
  1984   keyfilter = AList.find (op =)
  1985 
  1986 * eq_fst and eq_snd now take explicit equality parameter, thus
  1987   avoiding eqtypes. Naive rewrites:
  1988 
  1989     eq_fst = eq_fst (op =)
  1990     eq_snd = eq_snd (op =)
  1991 
  1992 * Removed deprecated apl and apr (rarely used).
  1993   Naive rewrites:
  1994 
  1995     apl (n, op) =>>= curry op n
  1996     apr (op, m) =>>= fn n => op (n, m)
  1997 
  1998 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1999 provides a reasonably efficient light-weight implementation of sets as
  2000 lists.
  2001 
  2002 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2003 few new operations; existing lookup and update are now curried to
  2004 follow natural argument order (for use with fold etc.);
  2005 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2006 
  2007 * Pure/General: output via the Isabelle channels of
  2008 writeln/warning/error etc. is now passed through Output.output, with a
  2009 hook for arbitrary transformations depending on the print_mode
  2010 (cf. Output.add_mode -- the first active mode that provides a output
  2011 function wins).  Already formatted output may be embedded into further
  2012 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2013 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2014 accommodate easy composition of diagnostic messages etc.  Programmers
  2015 rarely need to care about Output.output or Output.raw at all, with
  2016 some notable exceptions: Output.output is required when bypassing the
  2017 standard channels (writeln etc.), or in token translations to produce
  2018 properly formatted results; Output.raw is required when capturing
  2019 already output material that will eventually be presented to the user
  2020 a second time.  For the default print mode, both Output.output and
  2021 Output.raw have no effect.
  2022 
  2023 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2024 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2025 cumulative results are displayed at the end of a batch session.
  2026 
  2027 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2028 replaced by File.platform_path and File.shell_path (with appropriate
  2029 hooks).  This provides a clean interface for unusual systems where the
  2030 internal and external process view of file names are different.
  2031 
  2032 * Pure: more efficient orders for basic syntactic entities: added
  2033 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2034 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2035 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2036 orders now -- potential INCOMPATIBILITY for code that depends on a
  2037 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2038 Library.sort_strings on result).
  2039 
  2040 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2041 fold_types traverse types/terms from left to right, observing natural
  2042 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2043 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2044 
  2045 * Pure: name spaces have been refined, with significant changes of the
  2046 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2047 to extern(_table).  The plain name entry path is superceded by a
  2048 general 'naming' context, which also includes the 'policy' to produce
  2049 a fully qualified name and external accesses of a fully qualified
  2050 name; NameSpace.extend is superceded by context dependent
  2051 Sign.declare_name.  Several theory and proof context operations modify
  2052 the naming context.  Especially note Theory.restore_naming and
  2053 ProofContext.restore_naming to get back to a sane state; note that
  2054 Theory.add_path is no longer sufficient to recover from
  2055 Theory.absolute_path in particular.
  2056 
  2057 * Pure: new flags short_names (default false) and unique_names
  2058 (default true) for controlling output of qualified names.  If
  2059 short_names is set, names are printed unqualified.  If unique_names is
  2060 reset, the name prefix is reduced to the minimum required to achieve
  2061 the original result when interning again, even if there is an overlap
  2062 with earlier declarations.
  2063 
  2064 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2065 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2066 (useful for printing error messages).  INCOMPATIBILITY.
  2067 
  2068 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2069 Theory.theory are now identified, referring to the universal
  2070 Context.theory (see Pure/context.ML).  Actual signature and theory
  2071 content is managed as theory data.  The old code and interfaces were
  2072 spread over many files and structures; the new arrangement introduces
  2073 considerable INCOMPATIBILITY to gain more clarity:
  2074 
  2075   Context -- theory management operations (name, identity, inclusion,
  2076     parents, ancestors, merge, etc.), plus generic theory data;
  2077 
  2078   Sign -- logical signature and syntax operations (declaring consts,
  2079     types, etc.), plus certify/read for common entities;
  2080 
  2081   Theory -- logical theory operations (stating axioms, definitions,
  2082     oracles), plus a copy of logical signature operations (consts,
  2083     types, etc.); also a few basic management operations (Theory.copy,
  2084     Theory.merge, etc.)
  2085 
  2086 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2087 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2088 for convenience -- they merely return the theory.
  2089 
  2090 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2091 
  2092 * Pure: the Isar proof context type is already defined early in Pure
  2093 as Context.proof (note that ProofContext.context and Proof.context are
  2094 aliases, where the latter is the preferred name).  This enables other
  2095 Isabelle components to refer to that type even before Isar is present.
  2096 
  2097 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2098 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2099 any of these kinds.  For example, Sign.intern typeK is now
  2100 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2101 Theory.hide_types.  Also note that former
  2102 Theory.hide_classes/types/consts are now
  2103 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2104 internalize their arguments!  INCOMPATIBILITY.
  2105 
  2106 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2107 datatype thmref (with constructors Name and NameSelection) instead of
  2108 plain string -- INCOMPATIBILITY;
  2109 
  2110 * Pure: cases produced by proof methods specify options, where NONE
  2111 means to remove case bindings -- INCOMPATIBILITY in
  2112 (RAW_)METHOD_CASES.
  2113 
  2114 * Pure: the following operations retrieve axioms or theorems from a
  2115 theory node or theory hierarchy, respectively:
  2116 
  2117   Theory.axioms_of: theory -> (string * term) list
  2118   Theory.all_axioms_of: theory -> (string * term) list
  2119   PureThy.thms_of: theory -> (string * thm) list
  2120   PureThy.all_thms_of: theory -> (string * thm) list
  2121 
  2122 * Pure: print_tac now outputs the goal through the trace channel.
  2123 
  2124 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2125 Reference Toplevel.debug (default false) controls detailed printing
  2126 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2127 controls execution profiling -- set to 1 for time and 2 for space
  2128 (both increase the runtime).
  2129 
  2130 * Isar session: The initial use of ROOT.ML is now always timed,
  2131 i.e. the log will show the actual process times, in contrast to the
  2132 elapsed wall-clock time that the outer shell wrapper produces.
  2133 
  2134 * Simplifier: improved handling of bound variables (nameless
  2135 representation, avoid allocating new strings).  Simprocs that invoke
  2136 the Simplifier recursively should use Simplifier.inherit_bounds to
  2137 avoid local name clashes.  Failure to do so produces warnings
  2138 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2139 for further details.
  2140 
  2141 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2142 bindings for all theorems stored within a given theory; this may help
  2143 in porting non-Isar theories to Isar ones, while keeping ML proof
  2144 scripts for the time being.
  2145 
  2146 * ML operator HTML.with_charset specifies the charset begin used for
  2147 generated HTML files.  For example:
  2148 
  2149   HTML.with_charset "utf-8" use_thy "Hebrew";
  2150   HTML.with_charset "utf-8" use_thy "Chinese";
  2151 
  2152 
  2153 *** System ***
  2154 
  2155 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2156 isabelle, isatool etc.).
  2157 
  2158 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2159 isatool doc, isatool mkdir, display_drafts etc.).
  2160 
  2161 * isatool usedir: option -f allows specification of the ML file to be
  2162 used by Isabelle; default is ROOT.ML.
  2163 
  2164 * New isatool version outputs the version identifier of the Isabelle
  2165 distribution being used.
  2166 
  2167 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2168 (containing Boolean satisfiability problems) into Isabelle/HOL
  2169 theories.
  2170 
  2171 
  2172 
  2173 New in Isabelle2004 (April 2004)
  2174 --------------------------------
  2175 
  2176 *** General ***
  2177 
  2178 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2179   Replaces linorder.ML.
  2180 
  2181 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2182   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2183   (\<a>...\<z>), are now considered normal letters, and can therefore
  2184   be used anywhere where an ASCII letter (a...zA...Z) has until
  2185   now. COMPATIBILITY: This obviously changes the parsing of some
  2186   terms, especially where a symbol has been used as a binder, say
  2187   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2188   as an identifier.  Fix it by inserting a space around former
  2189   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2190   existing theory and ML files.
  2191 
  2192 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2193 
  2194 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2195   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2196   a normal (but invisible) letter. For multiple letter subscripts repeat
  2197   \<^isub> like this: x\<^isub>1\<^isub>2.
  2198 
  2199 * Pure: There are now sub-/superscripts that can span more than one
  2200   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2201   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2202   superscript. The new control characters are not identifier parts.
  2203 
  2204 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2205   content of "..." to the latex file instead of \isacntrl... . The "..."
  2206   may consist of any printable characters excluding the end bracket >.
  2207 
  2208 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2209   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2210   declare constants "final", which prevents their being given a definition
  2211   later.  It is useful for constants whose behaviour is fixed axiomatically
  2212   rather than definitionally, such as the meta-logic connectives.
  2213 
  2214 * Pure: 'instance' now handles general arities with general sorts
  2215   (i.e. intersections of classes),
  2216 
  2217 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2218   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2219   It can be changed to alter the colors/layout of generated pages.
  2220 
  2221 
  2222 *** Isar ***
  2223 
  2224 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2225   cut_tac, subgoal_tac and thin_tac:
  2226   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2227     locales are no longer forced to write Isar proof scripts.
  2228     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2229     emulations.
  2230   - INCOMPATIBILITY: names of variables to be instantiated may no
  2231     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2232     This is consistent with the instantiation attribute "where".
  2233 
  2234 * Attributes "where" and "of":
  2235   - Now take type variables of instantiated theorem into account when reading
  2236     the instantiation string.  This fixes a bug that caused instantiated
  2237     theorems to have too special types in some circumstances.
  2238   - "where" permits explicit instantiations of type variables.
  2239 
  2240 * Calculation commands "moreover" and "also" no longer interfere with
  2241   current facts ("this"), admitting arbitrary combinations with "then"
  2242   and derived forms.
  2243 
  2244 * Locales:
  2245   - Goal statements involving the context element "includes" no longer
  2246     generate theorems with internal delta predicates (those ending on
  2247     "_axioms") in the premise.
  2248     Resolve particular premise with <locale>.intro to obtain old form.
  2249   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2250     specification and "includes" elements in goal statement.
  2251   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2252     [intro?] and [elim?] (respectively) by default.
  2253   - Experimental command for instantiation of locales in proof contexts:
  2254         instantiate <label>[<attrs>]: <loc>
  2255     Instantiates locale <loc> and adds all its theorems to the current context
  2256     taking into account their attributes.  Label and attrs are optional
  2257     modifiers, like in theorem declarations.  If present, names of
  2258     instantiated theorems are qualified with <label>, and the attributes
  2259     <attrs> are applied after any attributes these theorems might have already.
  2260       If the locale has assumptions, a chained fact of the form
  2261     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2262     are derived.  The command does not support old-style locales declared
  2263     with "locale (open)".
  2264       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2265 
  2266 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2267   (Isar) contexts.
  2268 
  2269 
  2270 *** HOL ***
  2271 
  2272 * Proof import: new image HOL4 contains the imported library from
  2273   the HOL4 system with about 2500 theorems. It is imported by
  2274   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2275   can be used like any other Isabelle image.  See
  2276   HOL/Import/HOL/README for more information.
  2277 
  2278 * Simplifier:
  2279   - Much improved handling of linear and partial orders.
  2280     Reasoners for linear and partial orders are set up for type classes
  2281     "linorder" and "order" respectively, and are added to the default simpset
  2282     as solvers.  This means that the simplifier can build transitivity chains
  2283     to solve goals from the assumptions.
  2284   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2285     of blast or auto after simplification become unnecessary because the goal
  2286     is solved by simplification already.
  2287 
  2288 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2289     all proved in axiomatic type classes for semirings, rings and fields.
  2290 
  2291 * Numerics:
  2292   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2293     now formalized using the Ring_and_Field theory mentioned above.
  2294   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2295     than before, because now they are set up once in a generic manner.
  2296   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2297     Look for the general versions in Ring_and_Field (and Power if they concern
  2298     exponentiation).
  2299 
  2300 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2301 
  2302 * Records:
  2303   - Record types are now by default printed with their type abbreviation
  2304     instead of the list of all field types. This can be configured via
  2305     the reference "print_record_type_abbr".
  2306   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2307     (not enabled by default).
  2308   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2309     EX x. x = sel r to True (not enabled by default).
  2310   - Tactic "record_split_simp_tac" to split and simplify records added.
  2311 
  2312 * 'specification' command added, allowing for definition by
  2313   specification.  There is also an 'ax_specification' command that
  2314   introduces the new constants axiomatically.
  2315 
  2316 * arith(_tac) is now able to generate counterexamples for reals as well.
  2317 
  2318 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2319 
  2320 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2321   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2322 
  2323 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2324   matrix theory to linear programming.
  2325 
  2326 * Unions and Intersections:
  2327   The latex output syntax of UN and INT has been changed
  2328   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2329   i.e. the index formulae has become a subscript.
  2330   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2331 
  2332 * Unions and Intersections over Intervals:
  2333   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2334   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2335   like in normal math, and corresponding versions for < and for intersection.
  2336 
  2337 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2338   lexicographic dictonary ordering has been added as "lexord".
  2339 
  2340 * ML: the legacy theory structures Int and List have been removed. They had
  2341   conflicted with ML Basis Library structures having the same names.
  2342 
  2343 * 'refute' command added to search for (finite) countermodels.  Only works
  2344   for a fragment of HOL.  The installation of an external SAT solver is
  2345   highly recommended.  See "HOL/Refute.thy" for details.
  2346 
  2347 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2348   formulae under an assignment of free variables to random values.
  2349   In contrast to 'refute', it can deal with inductive datatypes,
  2350   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2351   for examples.
  2352 
  2353 
  2354 *** HOLCF ***
  2355 
  2356 * Streams now come with concatenation and are part of the HOLCF image
  2357 
  2358 
  2359 
  2360 New in Isabelle2003 (May 2003)
  2361 ------------------------------
  2362 
  2363 *** General ***
  2364 
  2365 * Provers/simplifier:
  2366 
  2367   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2368     Assumptions are now subject to complete mutual simplification,
  2369     not just from left to right. The simplifier now preserves
  2370     the order of assumptions.
  2371 
  2372     Potential INCOMPATIBILITY:
  2373 
  2374     -- simp sometimes diverges where the old version did
  2375        not, e.g. invoking simp on the goal
  2376 
  2377         [| P (f x); y = x; f x = f y |] ==> Q
  2378 
  2379        now gives rise to the infinite reduction sequence
  2380 
  2381         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2382 
  2383        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2384        kind of problem.
  2385 
  2386     -- Tactics combining classical reasoner and simplification (such as auto)
  2387        are also affected by this change, because many of them rely on
  2388        simp. They may sometimes diverge as well or yield a different numbers
  2389        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2390        in case of problems. Sometimes subsequent calls to the classical
  2391        reasoner will fail because a preceeding call to the simplifier too
  2392        eagerly simplified the goal, e.g. deleted redundant premises.
  2393 
  2394   - The simplifier trace now shows the names of the applied rewrite rules
  2395 
  2396   - You can limit the number of recursive invocations of the simplifier
  2397     during conditional rewriting (where the simplifie tries to solve the
  2398     conditions before applying the rewrite rule):
  2399     ML "simp_depth_limit := n"
  2400     where n is an integer. Thus you can force termination where previously
  2401     the simplifier would diverge.
  2402 
  2403   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2404 
  2405   - No longer aborts on failed congruence proof.  Instead, the
  2406     congruence is ignored.
  2407 
  2408 * Pure: New generic framework for extracting programs from constructive
  2409   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2410   as HOL/Extraction for some case studies.
  2411 
  2412 * Pure: The main goal of the proof state is no longer shown by default, only
  2413 the subgoals. This behaviour is controlled by a new flag.
  2414    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2415 (ML: Proof.show_main_goal).
  2416 
  2417 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2418 rules whose conclusion matches subgoal 1:
  2419       PG menu: Isabelle/Isar -> Show me -> matching rules
  2420 The rules are ordered by how closely they match the subgoal.
  2421 In particular, rules that solve a subgoal outright are displayed first
  2422 (or rather last, the way they are printed).
  2423 (ML: ProofGeneral.print_intros())
  2424 
  2425 * Pure: New flag trace_unify_fail causes unification to print
  2426 diagnostic information (PG: in trace buffer) when it fails. This is
  2427 useful for figuring out why single step proofs like rule, erule or
  2428 assumption failed.
  2429 
  2430 * Pure: Locale specifications now produce predicate definitions
  2431 according to the body of text (covering assumptions modulo local
  2432 definitions); predicate "loc_axioms" covers newly introduced text,
  2433 while "loc" is cumulative wrt. all included locale expressions; the
  2434 latter view is presented only on export into the global theory
  2435 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2436 on the old view without predicates;
  2437 
  2438 * Pure: predefined locales "var" and "struct" are useful for sharing
  2439 parameters (as in CASL, for example); just specify something like
  2440 ``var x + var y + struct M'' as import;
  2441 
  2442 * Pure: improved thms_containing: proper indexing of facts instead of
  2443 raw theorems; check validity of results wrt. current name space;
  2444 include local facts of proof configuration (also covers active
  2445 locales), cover fixed variables in index; may use "_" in term
  2446 specification; an optional limit for the number of printed facts may
  2447 be given (the default is 40);
  2448 
  2449 * Pure: disallow duplicate fact bindings within new-style theory files
  2450 (batch-mode only);
  2451 
  2452 * Provers: improved induct method: assumptions introduced by case
  2453 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2454 the goal statement); "foo" still refers to all facts collectively;
  2455 
  2456 * Provers: the function blast.overloaded has been removed: all constants
  2457 are regarded as potentially overloaded, which improves robustness in exchange
  2458 for slight decrease in efficiency;
  2459 
  2460 * Provers/linorder: New generic prover for transitivity reasoning over
  2461 linear orders.  Note: this prover is not efficient!
  2462 
  2463 * Isar: preview of problems to finish 'show' now produce an error
  2464 rather than just a warning (in interactive mode);
  2465 
  2466 
  2467 *** HOL ***
  2468 
  2469 * arith(_tac)
  2470 
  2471  - Produces a counter example if it cannot prove a goal.
  2472    Note that the counter example may be spurious if the goal is not a formula
  2473    of quantifier-free linear arithmetic.
  2474    In ProofGeneral the counter example appears in the trace buffer.
  2475 
  2476  - Knows about div k and mod k where k is a numeral of type nat or int.
  2477 
  2478  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2479    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2480    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2481 
  2482 * simp's arithmetic capabilities have been enhanced a bit: it now
  2483 takes ~= in premises into account (by performing a case split);
  2484 
  2485 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2486 are distributed over a sum of terms;
  2487 
  2488 * New tactic "trans_tac" and method "trans" instantiate
  2489 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2490 "<=", "<" and "=").
  2491 
  2492 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2493 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2494 
  2495 * 'typedef' command has new option "open" to suppress the set
  2496 definition;
  2497 
  2498 * functions Min and Max on finite sets have been introduced (theory
  2499 Finite_Set);
  2500 
  2501 * attribute [symmetric] now works for relations as well; it turns
  2502 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2503 
  2504 * induct over a !!-quantified statement (say !!x1..xn):
  2505   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2506 
  2507 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2508 %x. None. Warning: empty_def now refers to the previously hidden definition
  2509 of the empty set.
  2510 
  2511 * Algebra: formalization of classical algebra.  Intended as base for
  2512 any algebraic development in Isabelle.  Currently covers group theory
  2513 (up to Sylow's theorem) and ring theory (Universal Property of
  2514 Univariate Polynomials).  Contributions welcome;
  2515 
  2516 * GroupTheory: deleted, since its material has been moved to Algebra;
  2517 
  2518 * Complex: new directory of the complex numbers with numeric constants,
  2519 nonstandard complex numbers, and some complex analysis, standard and
  2520 nonstandard (Jacques Fleuriot);
  2521 
  2522 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2523 
  2524 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2525 Fleuriot);
  2526 
  2527 * Real/HahnBanach: updated and adapted to locales;
  2528 
  2529 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2530 Gray and Kramer);
  2531 
  2532 * UNITY: added the Meier-Sanders theory of progress sets;
  2533 
  2534 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2535 as abstract algorithms, instantiated to the JVM;
  2536 
  2537 * Bali: Java source language formalization. Type system, operational
  2538 semantics, axiomatic semantics. Supported language features:
  2539 classes, interfaces, objects,virtual methods, static methods,
  2540 static/instance fields, arrays, access modifiers, definite
  2541 assignment, exceptions.
  2542 
  2543 
  2544 *** ZF ***
  2545 
  2546 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2547 universe, etc.);
  2548 
  2549 * Main ZF: virtually all theories converted to new-style format;
  2550 
  2551 
  2552 *** ML ***
  2553 
  2554 * Pure: Tactic.prove provides sane interface for internal proofs;
  2555 omits the infamous "standard" operation, so this is more appropriate
  2556 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2557 
  2558 * Pure: improved error reporting of simprocs;
  2559 
  2560 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2561 up simprocs;
  2562 
  2563 
  2564 *** Document preparation ***
  2565 
  2566 * uses \par instead of \\ for line breaks in theory text. This may
  2567 shift some page breaks in large documents. To get the old behaviour
  2568 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2569 
  2570 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2571 other packages
  2572 
  2573 * \<euro> now needs package babel/greek instead of marvosym (which
  2574 broke \Rightarrow)
  2575 
  2576 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2577 textcomp package)
  2578 
  2579 
  2580 
  2581 New in Isabelle2002 (March 2002)
  2582 --------------------------------
  2583 
  2584 *** Document preparation ***
  2585 
  2586 * greatly simplified document preparation setup, including more
  2587 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2588 instructive isatool mkdir; users should basically be able to get
  2589 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2590 users may run a separate document processing stage manually like this:
  2591 "isatool usedir -D output HOL Test && isatool document Test/output";
  2592 
  2593 * theory dependency graph may now be incorporated into documents;
  2594 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2595 with \includegraphics of LaTeX;
  2596 
  2597 * proper spacing of consecutive markup elements, especially text
  2598 blocks after section headings;
  2599 
  2600 * support bold style (for single symbols only), input syntax is like
  2601 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2602 
  2603 * \<bullet> is now output as bold \cdot by default, which looks much
  2604 better in printed text;
  2605 
  2606 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2607 note that these symbols are currently unavailable in Proof General /
  2608 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2609 
  2610 * isatool latex no longer depends on changed TEXINPUTS, instead
  2611 isatool document copies the Isabelle style files to the target
  2612 location;
  2613 
  2614 
  2615 *** Isar ***
  2616 
  2617 * Pure/Provers: improved proof by cases and induction;
  2618   - 'case' command admits impromptu naming of parameters (such as
  2619     "case (Suc n)");
  2620   - 'induct' method divinates rule instantiation from the inductive
  2621     claim; no longer requires excessive ?P bindings for proper
  2622     instantiation of cases;
  2623   - 'induct' method properly enumerates all possibilities of set/type
  2624     rules; as a consequence facts may be also passed through *type*
  2625     rules without further ado;
  2626   - 'induct' method now derives symbolic cases from the *rulified*
  2627     rule (before it used to rulify cases stemming from the internal
  2628     atomized version); this means that the context of a non-atomic
  2629     statement becomes is included in the hypothesis, avoiding the
  2630     slightly cumbersome show "PROP ?case" form;
  2631   - 'induct' may now use elim-style induction rules without chaining
  2632     facts, using ``missing'' premises from the goal state; this allows
  2633     rules stemming from inductive sets to be applied in unstructured
  2634     scripts, while still benefitting from proper handling of non-atomic
  2635     statements; NB: major inductive premises need to be put first, all
  2636     the rest of the goal is passed through the induction;
  2637   - 'induct' proper support for mutual induction involving non-atomic
  2638     rule statements (uses the new concept of simultaneous goals, see
  2639     below);
  2640   - append all possible rule selections, but only use the first
  2641     success (no backtracking);
  2642   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2643   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2644   - added 'print_induct_rules' (covered by help item in recent Proof
  2645     General versions);
  2646   - moved induct/cases attributes to Pure, methods to Provers;
  2647   - generic method setup instantiated for FOL and HOL;
  2648 
  2649 * Pure: support multiple simultaneous goal statements, for example
  2650 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2651 meta-level mechanism, this acts as if several individual goals had
  2652 been stated separately; in particular common proof methods need to be
  2653 repeated in order to cover all claims; note that a single elimination
  2654 step is *not* sufficient to establish the two conjunctions, so this
  2655 fails:
  2656 
  2657   assume "A & B" then have A and B ..   (*".." fails*)
  2658 
  2659 better use "obtain" in situations as above; alternative refer to
  2660 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2661 
  2662 * Pure: proper integration with ``locales''; unlike the original
  2663 version by Florian Kammller, Isar locales package high-level proof
  2664 contexts rather than raw logical ones (e.g. we admit to include
  2665 attributes everywhere); operations on locales include merge and
  2666 rename; support for implicit arguments (``structures''); simultaneous
  2667 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2668 some examples;
  2669 
  2670 * Pure: the following commands have been ``localized'', supporting a
  2671 target locale specification "(in name)": 'lemma', 'theorem',
  2672 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2673 stored both within the locale and at the theory level (exported and
  2674 qualified by the locale name);
  2675 
  2676 * Pure: theory goals may now be specified in ``long'' form, with
  2677 ad-hoc contexts consisting of arbitrary locale elements. for example
  2678 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2679 definitions may be given, too); the result is a meta-level rule with
  2680 the context elements being discharged in the obvious way;
  2681 
  2682 * Pure: new proof command 'using' allows to augment currently used
  2683 facts after a goal statement ('using' is syntactically analogous to
  2684 'apply', but acts on the goal's facts only); this allows chained facts
  2685 to be separated into parts given before and after a claim, as in
  2686 ``from a and b have C using d and e <proof>'';
  2687 
  2688 * Pure: renamed "antecedent" case to "rule_context";
  2689 
  2690 * Pure: new 'judgment' command records explicit information about the
  2691 object-logic embedding (used by several tools internally); no longer
  2692 use hard-wired "Trueprop";
  2693 
  2694 * Pure: added 'corollary' command;
  2695 
  2696 * Pure: fixed 'token_translation' command;
  2697 
  2698 * Pure: removed obsolete 'exported' attribute;
  2699 
  2700 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2701 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2702 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2703 
  2704 * Pure: method 'atomize' presents local goal premises as object-level
  2705 statements (atomic meta-level propositions); setup controlled via
  2706 rewrite rules declarations of 'atomize' attribute; example
  2707 application: 'induct' method with proper rule statements in improper
  2708 proof *scripts*;
  2709 
  2710 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2711 now consider the syntactic context of assumptions, giving a better
  2712 chance to get type-inference of the arguments right (this is
  2713 especially important for locales);
  2714 
  2715 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2716 mode;
  2717 
  2718 * Pure/obtain: the formal conclusion "thesis", being marked as
  2719 ``internal'', may no longer be reference directly in the text;
  2720 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2721 situations;
  2722 
  2723 * Pure: generic 'sym' attribute which declares a rule both as pure
  2724 'elim?' and for the 'symmetric' operation;
  2725 
  2726 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2727 text; the fixed correlation with particular command syntax has been
  2728 discontinued;
  2729 
  2730 * Pure: new method 'rules' is particularly well-suited for proof
  2731 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2732 but often produces more compact proof terms with less detours;
  2733 
  2734 * Pure/Provers/classical: simplified integration with pure rule
  2735 attributes and methods; the classical "intro?/elim?/dest?"
  2736 declarations coincide with the pure ones; the "rule" method no longer
  2737 includes classically swapped intros; "intro" and "elim" methods no
  2738 longer pick rules from the context; also got rid of ML declarations
  2739 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2740 INCOMPATIBILITY;
  2741 
  2742 * Provers/classical: attribute 'swapped' produces classical inversions
  2743 of introduction rules;
  2744 
  2745 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2746 rules instead of full simplifier context; 'iff' attribute handles
  2747 conditional rules;
  2748 
  2749 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2750 
  2751 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2752 "(permissive)" option to recover old behavior;
  2753 
  2754 * HOL: 'inductive' no longer features separate (collective) attributes
  2755 for 'intros' (was found too confusing);
  2756 
  2757 * HOL: properly declared induction rules less_induct and
  2758 wf_induct_rule;
  2759 
  2760 
  2761 *** HOL ***
  2762 
  2763 * HOL: moved over to sane numeral syntax; the new policy is as
  2764 follows:
  2765 
  2766   - 0 and 1 are polymorphic constants, which are defined on any
  2767   numeric type (nat, int, real etc.);
  2768 
  2769   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2770   binary representation internally;
  2771 
  2772   - type nat has special constructor Suc, and generally prefers Suc 0
  2773   over 1::nat and Suc (Suc 0) over 2::nat;
  2774 
  2775 This change may cause significant problems of INCOMPATIBILITY; here
  2776 are some hints on converting existing sources:
  2777 
  2778   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2779   entities, so expressions involving "-" (unary or binary minus) need
  2780   to be spaced properly;
  2781 
  2782   - existing occurrences of "1" may need to be constraint "1::nat" or
  2783   even replaced by Suc 0; similar for old "2";
  2784 
  2785   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2786 
  2787   - remove all special provisions on numerals in proofs;
  2788 
  2789 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2790 representation (depends on bin_arith_simps in the default context);
  2791 
  2792 * HOL: symbolic syntax for x^2 (numeral 2);
  2793 
  2794 * HOL: the class of all HOL types is now called "type" rather than
  2795 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2796 in axclass/classes, instance/arities, and (usually rare) occurrences
  2797 in typings (of consts etc.); internally the class is called
  2798 "HOL.type", ML programs should refer to HOLogic.typeS;
  2799 
  2800 * HOL/record package improvements:
  2801   - new derived operations "fields" to build a partial record section,
  2802     "extend" to promote a fixed record to a record scheme, and
  2803     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2804     declared as simp by default;
  2805   - shared operations ("more", "fields", etc.) now need to be always
  2806     qualified) --- potential INCOMPATIBILITY;
  2807   - removed "make_scheme" operations (use "make" with "extend") --
  2808     INCOMPATIBILITY;
  2809   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2810   - provides cases/induct rules for use with corresponding Isar
  2811     methods (for concrete records, record schemes, concrete more
  2812     parts, and schematic more parts -- in that order);
  2813   - internal definitions directly based on a light-weight abstract
  2814     theory of product types over typedef rather than datatype;
  2815 
  2816 * HOL: generic code generator for generating executable ML code from
  2817 specifications; specific support for HOL constructs such as inductive
  2818 datatypes and sets, as well as recursive functions; can be invoked
  2819 via 'generate_code' theory section;
  2820 
  2821 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2822 
  2823 * HOL: consolidated and renamed several theories.  In particular:
  2824         Ord.thy has been absorbed into HOL.thy
  2825         String.thy has been absorbed into List.thy
  2826 
  2827 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2828 (beware of argument permutation!);
  2829 
  2830 * HOL: linorder_less_split superseded by linorder_cases;
  2831 
  2832 * HOL/List: "nodups" renamed to "distinct";
  2833 
  2834 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2835 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2836   - Ex_def has changed, now need to use some_eq_ex
  2837 
  2838 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2839 in this (rare) case use:
  2840 
  2841   delSWrapper "split_all_tac"
  2842   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2843 
  2844 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2845 MAY FAIL;
  2846 
  2847 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2848 Isabelle's type classes, ^ on functions and relations has too general
  2849 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2850 necessary to attach explicit type constraints;
  2851 
  2852 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2853 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2854 renamed accordingly (eg "compI" -> "rel_compI").
  2855 
  2856 * HOL: syntax translations now work properly with numerals and records
  2857 expressions;
  2858 
  2859 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2860 of "lam" -- INCOMPATIBILITY;
  2861 
  2862 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2863 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2864 renamed "Product_Type.unit";
  2865 
  2866 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2867 
  2868 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2869 the "cases" method);
  2870 
  2871 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2872 Florian Kammller);
  2873 
  2874 * HOL/IMP: updated and converted to new-style theory format; several
  2875 parts turned into readable document, with proper Isar proof texts and
  2876 some explanations (by Gerwin Klein);
  2877 
  2878 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2879 
  2880 * HOL-Hyperreal is now a logic image;
  2881 
  2882 
  2883 *** HOLCF ***
  2884 
  2885 * Isar: consts/constdefs supports mixfix syntax for continuous
  2886 operations;
  2887 
  2888 * Isar: domain package adapted to new-style theory format, e.g. see
  2889 HOLCF/ex/Dnat.thy;
  2890 
  2891 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2892 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2893 lift.induct_tac, always use UU instead of Undef;
  2894 
  2895 * HOLCF/IMP: updated and converted to new-style theory;
  2896 
  2897 
  2898 *** ZF ***
  2899 
  2900 * Isar: proper integration of logic-specific tools and packages,
  2901 including theory commands '(co)inductive', '(co)datatype',
  2902 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2903 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2904 
  2905 * theory Main no longer includes AC; for the Axiom of Choice, base
  2906 your theory on Main_ZFC;
  2907 
  2908 * the integer library now covers quotients and remainders, with many
  2909 laws relating division to addition, multiplication, etc.;
  2910 
  2911 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2912 typeless version of the formalism;
  2913 
  2914 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2915 format;
  2916 
  2917 * ZF/Induct: new directory for examples of inductive definitions,
  2918 including theory Multiset for multiset orderings; converted to
  2919 new-style theory format;
  2920 
  2921 * ZF: many new theorems about lists, ordinals, etc.;
  2922 
  2923 
  2924 *** General ***
  2925 
  2926 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2927 variable proof controls level of detail: 0 = no proofs (only oracle
  2928 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2929 also ref manual for further ML interfaces;
  2930 
  2931 * Pure/axclass: removed obsolete ML interface
  2932 goal_subclass/goal_arity;
  2933 
  2934 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2935 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2936 separate tokens, so expressions involving minus need to be spaced
  2937 properly;
  2938 
  2939 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2940 rather than "infixl" or "infixr";
  2941 
  2942 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2943 sort constraint specifications in type inference; e.g. "x::_::foo"
  2944 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2945 type variable);
  2946 
  2947 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2948 control output of nested => (types); the default behavior is
  2949 "type_brackets";
  2950 
  2951 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2952 tokens into AST constants;
  2953 
  2954 * Pure/syntax: prefer later declarations of translations and print
  2955 translation functions; potential INCOMPATIBILITY: need to reverse
  2956 multiple declarations for same syntax element constant;
  2957 
  2958 * Pure/show_hyps reset by default (in accordance to existing Isar
  2959 practice);
  2960 
  2961 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2962 addSafter;
  2963 
  2964 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2965 as well;
  2966 
  2967 * system: tested support for MacOS X; should be able to get Isabelle +
  2968 Proof General to work in a plain Terminal after installing Poly/ML
  2969 (e.g. from the Isabelle distribution area) and GNU bash alone
  2970 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2971 support requires further installations, e.g. from
  2972 http://fink.sourceforge.net/);
  2973 
  2974 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2975 
  2976 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2977 of 40 MB), cf. ML_OPTIONS;
  2978 
  2979 * system: Proof General keywords specification is now part of the
  2980 Isabelle distribution (see etc/isar-keywords.el);
  2981 
  2982 * system: support for persistent Proof General sessions (refrain from
  2983 outdating all loaded theories on startup); user may create writable
  2984 logic images like this: ``isabelle -q HOL Test'';
  2985 
  2986 * system: smart selection of Isabelle process versus Isabelle
  2987 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2988 run both "isabelle" and "Isabelle" even if file names are badly
  2989 damaged (executable inspects the case of the first letter of its own
  2990 name); added separate "isabelle-process" and "isabelle-interface";
  2991 
  2992 * system: refrain from any attempt at filtering input streams; no
  2993 longer support ``8bit'' encoding of old isabelle font, instead proper
  2994 iso-latin characters may now be used; the related isatools
  2995 "symbolinput" and "nonascii" have disappeared as well;
  2996 
  2997 * system: removed old "xterm" interface (the print modes "xterm" and
  2998 "xterm_color" are still available for direct use in a suitable
  2999 terminal);
  3000 
  3001 
  3002 
  3003 New in Isabelle99-2 (February 2001)
  3004 -----------------------------------
  3005 
  3006 *** Overview of INCOMPATIBILITIES ***
  3007 
  3008 * HOL: please note that theories in the Library and elsewhere often use the
  3009 new-style (Isar) format; to refer to their theorems in an ML script you must
  3010 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3011 
  3012 * HOL: inductive package no longer splits induction rule aggressively,
  3013 but only as far as specified by the introductions given; the old
  3014 format may be recovered via ML function complete_split_rule or attribute
  3015 'split_rule (complete)';
  3016 
  3017 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3018 gfp_Tarski to gfp_unfold;
  3019 
  3020 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3021 
  3022 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3023 relation); infix "^^" has been renamed "``"; infix "``" has been
  3024 renamed "`"; "univalent" has been renamed "single_valued";
  3025 
  3026 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3027 operation;
  3028 
  3029 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3030 
  3031 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3032 
  3033 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3034 consequence, it is no longer monotonic wrt. the local goal context
  3035 (which is now passed through the inductive cases);
  3036 
  3037 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3038 \<gg> to \<ggreater>;
  3039 
  3040 
  3041 *** Document preparation ***
  3042 
  3043 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3044 available: are "it" for near math-mode best-style output, "sl" for
  3045 slanted text style, and "tt" for plain type-writer; if no
  3046 \isabellestyle command is given, output is according to slanted
  3047 type-writer);
  3048 
  3049 * support sub/super scripts (for single symbols only), input syntax is
  3050 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3051 
  3052 * some more standard symbols; see Appendix A of the system manual for
  3053 the complete list of symbols defined in isabellesym.sty;
  3054 
  3055 * improved isabelle style files; more abstract symbol implementation
  3056 (should now use \isamath{...} and \isatext{...} in custom symbol
  3057 definitions);
  3058 
  3059 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3060 state; Note that presentation of goal states does not conform to
  3061 actual human-readable proof documents.  Please do not include goal
  3062 states into document output unless you really know what you are doing!
  3063 
  3064 * proper indentation of antiquoted output with proportional LaTeX
  3065 fonts;
  3066 
  3067 * no_document ML operator temporarily disables LaTeX document
  3068 generation;
  3069 
  3070 * isatool unsymbolize tunes sources for plain ASCII communication;
  3071 
  3072 
  3073 *** Isar ***
  3074 
  3075 * Pure: Isar now suffers initial goal statements to contain unbound
  3076 schematic variables (this does not conform to actual readable proof
  3077 documents, due to unpredictable outcome and non-compositional proof
  3078 checking); users who know what they are doing may use schematic goals
  3079 for Prolog-style synthesis of proven results;
  3080 
  3081 * Pure: assumption method (an implicit finishing) now handles actual
  3082 rules as well;
  3083 
  3084 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3085 initial goal, declare "that" only as Pure intro (only for single
  3086 steps); the "that" rule assumption may now be involved in implicit
  3087 finishing, thus ".." becomes a feasible for trivial obtains;
  3088 
  3089 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3090 instance proofs may be performed by "..";
  3091 
  3092 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3093 statements as well;
  3094 
  3095 * Pure: more robust selection of calculational rules;
  3096 
  3097 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3098 rule (as well as the assumption rule);
  3099 
  3100 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3101 lemmas, using the graph browser tool;
  3102 
  3103 * Pure: predict failure of "show" in interactive mode;
  3104 
  3105 * Pure: 'thms_containing' now takes actual terms as arguments;
  3106 
  3107 * HOL: improved method 'induct' --- now handles non-atomic goals
  3108 (potential INCOMPATIBILITY); tuned error handling;
  3109 
  3110 * HOL: cases and induct rules now provide explicit hints about the
  3111 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3112 any remaining facts are inserted into the goal verbatim;
  3113 
  3114 * HOL: local contexts (aka cases) may now contain term bindings as
  3115 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3116 the result to be shown in each case;
  3117 
  3118 * HOL: added 'recdef_tc' command;
  3119 
  3120 * isatool convert assists in eliminating legacy ML scripts;
  3121 
  3122 
  3123 *** HOL ***
  3124 
  3125 * HOL/Library: a collection of generic theories to be used together
  3126 with main HOL; the theory loader path already includes this directory
  3127 by default; the following existing theories have been moved here:
  3128 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3129 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3130 
  3131 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3132 modelling and verification task performed in Isabelle/HOL +
  3133 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3134 
  3135 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3136 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3137 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3138 'domain', this makes the theory consistent with mathematical
  3139 literature;
  3140 
  3141 * HOL basics: added overloaded operations "inverse" and "divide"
  3142 (infix "/"), syntax for generic "abs" operation, generic summation
  3143 operator \<Sum>;
  3144 
  3145 * HOL/typedef: simplified package, provide more useful rules (see also
  3146 HOL/subset.thy);
  3147 
  3148 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3149 now expressed as a proper nested rule (old-style tactic scripts may
  3150 require atomize_strip_tac to cope with non-atomic premises);
  3151 
  3152 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3153 to "split_conv" (old name still available for compatibility);
  3154 
  3155 * HOL: improved concrete syntax for strings (e.g. allows translation
  3156 rules with string literals);
  3157 
  3158 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3159  and Fleuriot's mechanization of analysis, including the transcendental
  3160  functions for the reals;
  3161 
  3162 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3163 
  3164 
  3165 *** CTT ***
  3166 
  3167 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3168 "lam" is displayed as TWO lambda-symbols
  3169 
  3170 * CTT: theory Main now available, containing everything (that is, Bool
  3171 and Arith);
  3172 
  3173 
  3174 *** General ***
  3175 
  3176 * Pure: the Simplifier has been implemented properly as a derived rule
  3177 outside of the actual kernel (at last!); the overall performance
  3178 penalty in practical applications is about 50%, while reliability of
  3179 the Isabelle inference kernel has been greatly improved;
  3180 
  3181 * print modes "brackets" and "no_brackets" control output of nested =>
  3182 (types) and ==> (props); the default behaviour is "brackets";
  3183 
  3184 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3185 as assumptions as well;
  3186 
  3187 * system: support Poly/ML 4.0;
  3188 
  3189 * system: isatool install handles KDE version 1 or 2;
  3190 
  3191 
  3192 
  3193 New in Isabelle99-1 (October 2000)
  3194 ----------------------------------
  3195 
  3196 *** Overview of INCOMPATIBILITIES ***
  3197 
  3198 * HOL: simplification of natural numbers is much changed; to partly
  3199 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3200 issue the following ML commands:
  3201 
  3202   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3203   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3204 
  3205 * HOL: simplification no longer dives into case-expressions; this is
  3206 controlled by "t.weak_case_cong" for each datatype t;
  3207 
  3208 * HOL: nat_less_induct renamed to less_induct;
  3209 
  3210 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3211 fixsome to patch .thy and .ML sources automatically;
  3212 
  3213   select_equality  -> some_equality
  3214   select_eq_Ex     -> some_eq_ex
  3215   selectI2EX       -> someI2_ex
  3216   selectI2         -> someI2
  3217   selectI          -> someI
  3218   select1_equality -> some1_equality
  3219   Eps_sym_eq       -> some_sym_eq_trivial
  3220   Eps_eq           -> some_eq_trivial
  3221 
  3222 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3223 
  3224 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3225 instead);
  3226 
  3227 * HOL: the recursion equations generated by 'recdef' are now called
  3228 f.simps instead of f.rules;
  3229 
  3230 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3231 
  3232 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3233 sometimes be needed;
  3234 
  3235 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3236 
  3237 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3238 
  3239 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3240 product is now "<*>" instead of "Times"; the lexicographic product is
  3241 now "<*lex*>" instead of "**";
  3242 
  3243 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3244 of main HOL, but was unused); better use HOL's datatype package;
  3245 
  3246 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3247 the old syntax may be recovered as follows:
  3248 
  3249   syntax (symbols)
  3250     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3251       (infixl "\\<oplus>" 100)
  3252 
  3253 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3254 
  3255 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3256 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3257 internally;
  3258 
  3259 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3260 changed from A/r to A//r;
  3261 
  3262 * ZF: new treatment of arithmetic (nat & int) may break some old
  3263 proofs;
  3264 
  3265 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3266 rulify -> rule_format, elimify -> elim_format, ...);
  3267 
  3268 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3269 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3270 should have to change intro!! to intro? only); replaced "delrule" by
  3271 "rule del";
  3272 
  3273 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3274 
  3275 * Provers: strengthened force_tac by using new first_best_tac;
  3276 
  3277 * LaTeX document preparation: several changes of isabelle.sty (see
  3278 lib/texinputs);
  3279 
  3280 
  3281 *** Document preparation ***
  3282 
  3283 * formal comments (text blocks etc.) in new-style theories may now
  3284 contain antiquotations of thm/prop/term/typ/text to be presented
  3285 according to latex print mode; concrete syntax is like this:
  3286 @{term[show_types] "f(x) = a + x"};
  3287 
  3288 * isatool mkdir provides easy setup of Isabelle session directories,
  3289 including proper document sources;
  3290 
  3291 * generated LaTeX sources are now deleted after successful run
  3292 (isatool document -c); may retain a copy somewhere else via -D option
  3293 of isatool usedir;
  3294 
  3295 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3296 style files, achieving self-contained LaTeX sources and simplifying
  3297 LaTeX debugging;
  3298 
  3299 * old-style theories now produce (crude) LaTeX output as well;
  3300 
  3301 * browser info session directories are now self-contained (may be put
  3302 on WWW server seperately); improved graphs of nested sessions; removed
  3303 graph for 'all sessions';
  3304 
  3305 * several improvements in isabelle style files; \isabellestyle{it}
  3306 produces fake math mode output; \isamarkupheader is now \section by
  3307 default; see lib/texinputs/isabelle.sty etc.;
  3308 
  3309 
  3310 *** Isar ***
  3311 
  3312 * Isar/Pure: local results and corresponding term bindings are now
  3313 subject to Hindley-Milner polymorphism (similar to ML); this
  3314 accommodates incremental type-inference very nicely;
  3315 
  3316 * Isar/Pure: new derived language element 'obtain' supports
  3317 generalized existence reasoning;
  3318 
  3319 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3320 support accumulation of results, without applying any rules yet;
  3321 useful to collect intermediate results without explicit name
  3322 references, and for use with transitivity rules with more than 2
  3323 premises;
  3324 
  3325 * Isar/Pure: scalable support for case-analysis type proofs: new
  3326 'case' language element refers to local contexts symbolically, as
  3327 produced by certain proof methods; internally, case names are attached
  3328 to theorems as "tags";
  3329 
  3330 * Isar/Pure: theory command 'hide' removes declarations from
  3331 class/type/const name spaces;
  3332 
  3333 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3334 indicate potential overloading;
  3335 
  3336 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3337 
  3338 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3339 "{a,b,c}" instead of {a,b,c};
  3340 
  3341 * Isar/Pure now provides its own version of intro/elim/dest
  3342 attributes; useful for building new logics, but beware of confusion
  3343 with the version in Provers/classical;
  3344 
  3345 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3346 case name 'antecedent';
  3347 
  3348 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3349 to the current context is now done automatically);
  3350 
  3351 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3352 for definining proof methods in ML;
  3353 
  3354 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3355 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3356 most cases, one should have to change intro!! to intro? only);
  3357 replaced "delrule" by "rule del";
  3358 
  3359 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3360 'symmetric' attribute (the latter supercedes [RS sym]);
  3361 
  3362 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3363 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3364 well (including splits);
  3365 
  3366 * Isar/Provers: Simplifier and Classical methods now support all kind
  3367 of modifiers used in the past, including 'cong', 'iff', etc.
  3368 
  3369 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3370 of Simplifier and Classical reasoner);
  3371 
  3372 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3373 now support named cases; major packages (inductive, datatype, primrec,
  3374 recdef) support case names and properly name parameters;
  3375 
  3376 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3377 monotonicity conditions are extracted to be proven at end of
  3378 calculations;
  3379 
  3380 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3381 method anyway;
  3382 
  3383 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3384 split_if split_if_asm; datatype package provides theorems foo.splits =
  3385 foo.split foo.split_asm for each datatype;
  3386 
  3387 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3388 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3389 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3390 use "(cases (simplified))" method in proper proof texts);
  3391 
  3392 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3393 
  3394 * Isar: names of theorems etc. may be natural numbers as well;
  3395 
  3396 * Isar: 'pr' command: optional arguments for goals_limit and
  3397 ProofContext.prems_limit; no longer prints theory contexts, but only
  3398 proof states;
  3399 
  3400 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3401 additional print modes to be specified; e.g. "pr(latex)" will print
  3402 proof state according to the Isabelle LaTeX style;
  3403 
  3404 * Isar: improved support for emulating tactic scripts, including proof
  3405 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3406 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3407 (for HOL datatypes);
  3408 
  3409 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3410 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3411 'proof method scripts' have to be in depth-first order;
  3412 
  3413 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3414 
  3415 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3416 should instead use individual commands for printing items
  3417 (print_commands, print_methods etc.);
  3418 
  3419 * Isar: added 'nothing' --- the empty list of theorems;
  3420 
  3421 
  3422 *** HOL ***
  3423 
  3424 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3425 corresponding virtual machine and a specification of its bytecode
  3426 verifier and a lightweight bytecode verifier, including proofs of
  3427 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3428 Cornelia Pusch (see also the homepage of project Bali at
  3429 http://isabelle.in.tum.de/Bali/);
  3430 
  3431 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3432 Clemens Ballarin;
  3433 
  3434 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3435 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3436 Rasmussen;
  3437 
  3438 * HOL/Lattice: fundamental concepts of lattice theory and order
  3439 structures, including duals, properties of bounds versus algebraic
  3440 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3441 Theorem for complete lattices etc.; may also serve as a demonstration
  3442 for abstract algebraic reasoning using axiomatic type classes, and
  3443 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3444 
  3445 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3446 von Oheimb;
  3447 
  3448 * HOL/IMPP: extension of IMP with local variables and mutually
  3449 recursive procedures, by David von Oheimb;
  3450 
  3451 * HOL/Lambda: converted into new-style theory and document;
  3452 
  3453 * HOL/ex/Multiquote: example of multiple nested quotations and
  3454 anti-quotations -- basically a generalized version of de-Bruijn
  3455 representation; very useful in avoiding lifting of operations;
  3456 
  3457 * HOL/record: added general record equality rule to simpset; fixed
  3458 select-update simplification procedure to handle extended records as
  3459 well; admit "r" as field name;
  3460 
  3461 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3462 other numeric types and also as the identity of groups, rings, etc.;
  3463 
  3464 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3465 Types nat and int belong to this axclass;
  3466 
  3467 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3468    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3469    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3470   two terms #m*u and #n*u are replaced by #(m+n)*u
  3471     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3472   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3473     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3474 
  3475 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3476 powerful prover for predicate logic but knows nothing of clasets; see
  3477 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3478 
  3479 * HOL: new version of "case_tac" subsumes both boolean case split and
  3480 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3481 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3482 
  3483 * HOL: simplification no longer dives into case-expressions: only the
  3484 selector expression is simplified, but not the remaining arms; to
  3485 enable full simplification of case-expressions for datatype t, you may
  3486 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3487 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3488 
  3489 * HOL/recdef: the recursion equations generated by 'recdef' for
  3490 function 'f' are now called f.simps instead of f.rules; if all
  3491 termination conditions are proved automatically, these simplification
  3492 rules are added to the simpset, as in primrec; rules may be named
  3493 individually as well, resulting in a separate list of theorems for
  3494 each equation;
  3495 
  3496 * HOL/While is a new theory that provides a while-combinator. It
  3497 permits the definition of tail-recursive functions without the
  3498 provision of a termination measure. The latter is necessary once the
  3499 invariant proof rule for while is applied.
  3500 
  3501 * HOL: new (overloaded) notation for the set of elements below/above
  3502 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3503 
  3504 * HOL: theorems impI, allI, ballI bound as "strip";
  3505 
  3506 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3507 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3508 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3509 
  3510 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3511 
  3512 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3513 main HOL, but was unused);
  3514 
  3515 * HOL: fewer consts declared as global (e.g. have to refer to
  3516 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3517 
  3518 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3519 in case of overlap with user translations (e.g. judgements over
  3520 tuples); (note that the underlying logical represenation is still
  3521 bogus);
  3522 
  3523 
  3524 *** ZF ***
  3525 
  3526 * ZF: simplification automatically cancels common terms in arithmetic
  3527 expressions over nat and int;
  3528 
  3529 * ZF: new treatment of nat to minimize type-checking: all operators
  3530 coerce their operands to a natural number using the function natify,
  3531 making the algebraic laws unconditional;
  3532 
  3533 * ZF: as above, for int: operators coerce their operands to an integer
  3534 using the function intify;
  3535 
  3536 * ZF: the integer library now contains many of the usual laws for the
  3537 orderings, including $<=, and monotonicity laws for $+ and $*;
  3538 
  3539 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3540 simplification;
  3541 
  3542 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3543 to the simplifier and classical reasoner simultaneously;
  3544 
  3545 
  3546 *** General ***
  3547 
  3548 * Provers: blast_tac now handles actual object-logic rules as
  3549 assumptions; note that auto_tac uses blast_tac internally as well;
  3550 
  3551 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3552 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3553 
  3554 * Provers: delrules now handles destruct rules as well (no longer need
  3555 explicit make_elim);
  3556 
  3557 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3558   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3559 use instead the strong form,
  3560   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3561 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3562 from destruct-rules;
  3563 
  3564 * Provers: Simplifier.easy_setup provides a fast path to basic
  3565 Simplifier setup for new object-logics;
  3566 
  3567 * Pure: AST translation rules no longer require constant head on LHS;
  3568 
  3569 * Pure: improved name spaces: ambiguous output is qualified; support
  3570 for hiding of names;
  3571 
  3572 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3573 XSYMBOL_HOME; no longer need to do manual configuration in most
  3574 situations;
  3575 
  3576 * system: compression of ML heaps images may now be controlled via -c
  3577 option of isabelle and isatool usedir (currently only observed by
  3578 Poly/ML);
  3579 
  3580 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3581 useful for remote X11);
  3582 
  3583 * system: provide TAGS file for Isabelle sources;
  3584 
  3585 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3586 order;
  3587 
  3588 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3589 timing flag supersedes proof_timing and Toplevel.trace;
  3590 
  3591 * ML: new combinators |>> and |>>> for incremental transformations
  3592 with secondary results (e.g. certain theory extensions):
  3593 
  3594 * ML: PureThy.add_defs gets additional argument to indicate potential
  3595 overloading (usually false);
  3596 
  3597 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3598 results;
  3599 
  3600 
  3601 
  3602 New in Isabelle99 (October 1999)
  3603 --------------------------------
  3604 
  3605 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3606 
  3607 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3608 are no longer simplified.  (This allows the simplifier to unfold recursive
  3609 functional programs.)  To restore the old behaviour, declare
  3610 
  3611     Delcongs [if_weak_cong];
  3612 
  3613 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3614 complement;
  3615 
  3616 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3617 
  3618 * HOL/datatype: mutual_induct_tac no longer exists --
  3619   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3620 
  3621 * HOL/typedef: fixed type inference for representing set; type
  3622 arguments now have to occur explicitly on the rhs as type constraints;
  3623 
  3624 * ZF: The con_defs part of an inductive definition may no longer refer
  3625 to constants declared in the same theory;
  3626 
  3627 * HOL, ZF: the function mk_cases, generated by the inductive
  3628 definition package, has lost an argument.  To simplify its result, it
  3629 uses the default simpset instead of a supplied list of theorems.
  3630 
  3631 * HOL/List: the constructors of type list are now Nil and Cons;
  3632 
  3633 * Simplifier: the type of the infix ML functions
  3634         setSSolver addSSolver setSolver addSolver
  3635 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3636 for packaging solvers. A solver is created via
  3637         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3638 where the string argument is only a comment.
  3639 
  3640 
  3641 *** Proof tools ***
  3642 
  3643 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3644 decision procedure for linear arithmetic. Currently it is used for
  3645 types `nat', `int', and `real' in HOL (see below); it can, should and
  3646 will be instantiated for other types and logics as well.
  3647 
  3648 * The simplifier now accepts rewrite rules with flexible heads, eg
  3649      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3650   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3651   matching.
  3652 
  3653 
  3654 *** General ***
  3655 
  3656 * New Isabelle/Isar subsystem provides an alternative to traditional
  3657 tactical theorem proving; together with the ProofGeneral/isar user
  3658 interface it offers an interactive environment for developing human
  3659 readable proof documents (Isar == Intelligible semi-automated
  3660 reasoning); for further information see isatool doc isar-ref,
  3661 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3662 
  3663 * improved and simplified presentation of theories: better HTML markup
  3664 (including colors), graph views in several sizes; isatool usedir now
  3665 provides a proper interface for user theories (via -P option); actual
  3666 document preparation based on (PDF)LaTeX is available as well (for
  3667 new-style theories only); see isatool doc system for more information;
  3668 
  3669 * native support for Proof General, both for classic Isabelle and
  3670 Isabelle/Isar;
  3671 
  3672 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3673 using the graph browser tool;
  3674 
  3675 * Isabelle manuals now also available as PDF;
  3676 
  3677 * theory loader rewritten from scratch (may not be fully
  3678 bug-compatible); old loadpath variable has been replaced by show_path,
  3679 add_path, del_path, reset_path functions; new operations such as
  3680 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3681 isatool doc ref);
  3682 
  3683 * improved isatool install: option -k creates KDE application icon,
  3684 option -p DIR installs standalone binaries;
  3685 
  3686 * added ML_PLATFORM setting (useful for cross-platform installations);
  3687 more robust handling of platform specific ML images for SML/NJ;
  3688 
  3689 * the settings environment is now statically scoped, i.e. it is never
  3690 created again in sub-processes invoked from isabelle, isatool, or
  3691 Isabelle;
  3692 
  3693 * path element specification '~~' refers to '$ISABELLE_HOME';
  3694 
  3695 * in locales, the "assumes" and "defines" parts may be omitted if
  3696 empty;
  3697 
  3698 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3699 long arrows);
  3700 
  3701 * new print_mode "HTML";
  3702 
  3703 * new flag show_tags controls display of tags of theorems (which are
  3704 basically just comments that may be attached by some tools);
  3705 
  3706 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3707 mode and goal output format:
  3708 
  3709 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3710 244c244
  3711 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3712 ---
  3713 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3714 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3715 181c181
  3716 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3717 ---
  3718 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3719 
  3720 * function bind_thms stores lists of theorems (cf. bind_thm);
  3721 
  3722 * new shorthand tactics ftac, eatac, datac, fatac;
  3723 
  3724 * qed (and friends) now accept "" as result name; in that case the
  3725 theorem is not stored, but proper checks and presentation of the
  3726 result still apply;
  3727 
  3728 * theorem database now also indexes constants "Trueprop", "all",
  3729 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3730 
  3731 
  3732 *** HOL ***
  3733 
  3734 ** HOL arithmetic **
  3735 
  3736 * There are now decision procedures for linear arithmetic over nat and
  3737 int:
  3738 
  3739 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3740 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3741 are treated as atomic; subformulae not involving type `nat' or `int'
  3742 are ignored; quantified subformulae are ignored unless they are
  3743 positive universal or negative existential. The tactic has to be
  3744 invoked by hand and can be a little bit slow. In particular, the
  3745 running time is exponential in the number of occurrences of `min' and
  3746 `max', and `-' on `nat'.
  3747 
  3748 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3749 (negated) (in)equalities among the premises and the conclusion into
  3750 account (i.e. no compound formulae) and does not know about `min' and
  3751 `max', and `-' on `nat'. It is fast and is used automatically by the
  3752 simplifier.
  3753 
  3754 NB: At the moment, these decision procedures do not cope with mixed
  3755 nat/int formulae where the two parts interact, such as `m < n ==>
  3756 int(m) < int(n)'.
  3757 
  3758 * HOL/Numeral provides a generic theory of numerals (encoded
  3759 efficiently as bit strings); setup for types nat/int/real is in place;
  3760 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3761 int, existing theories and proof scripts may require a few additional
  3762 type constraints;
  3763 
  3764 * integer division and remainder can now be performed on constant
  3765 arguments;
  3766 
  3767 * many properties of integer multiplication, division and remainder
  3768 are now available;
  3769 
  3770 * An interface to the Stanford Validity Checker (SVC) is available through the
  3771 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3772 are proved automatically.  SVC must be installed separately, and its results
  3773 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3774 invocation of the underlying oracle).  For SVC see
  3775   http://verify.stanford.edu/SVC
  3776 
  3777 * IsaMakefile: the HOL-Real target now builds an actual image;
  3778 
  3779 
  3780 ** HOL misc **
  3781 
  3782 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3783 (in Isabelle/Isar) -- by Gertrud Bauer;
  3784 
  3785 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3786 analysis for assembly languages with subtypes;
  3787 
  3788 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3789 -- avoids syntactic ambiguities and treats state, transition, and
  3790 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3791 changed syntax and (many) tactics;
  3792 
  3793 * HOL/inductive: Now also handles more general introduction rules such
  3794   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3795   theorems are now maintained within the theory (maintained via the
  3796   "mono" attribute);
  3797 
  3798 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3799   (using function types) such as
  3800 
  3801   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3802 
  3803 * HOL/record: record_simproc (part of the default simpset) takes care
  3804 of selectors applied to updated records; record_split_tac is no longer
  3805 part of the default claset; update_defs may now be removed from the
  3806 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3807 
  3808   claset_ref () := claset() addSWrapper record_split_wrapper;
  3809   Delsimprocs [record_simproc]
  3810 
  3811 * HOL/typedef: fixed type inference for representing set; type
  3812 arguments now have to occur explicitly on the rhs as type constraints;
  3813 
  3814 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3815 names rather than an ML expression;
  3816 
  3817 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3818 supplied later.  Program schemes can be defined, such as
  3819     "While B C s = (if B s then While B C (C s) else s)"
  3820 where the well-founded relation can be chosen after B and C have been given.
  3821 
  3822 * HOL/List: the constructors of type list are now Nil and Cons;
  3823 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3824 course, ML tools referring to List.list.op # etc. have to be adapted;
  3825 
  3826 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3827 disabled by default; run isabelle with option -m HOL to get back to
  3828 the original Gordon/HOL-style output;
  3829 
  3830 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3831 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3832 
  3833 * HOL basic syntax simplified (more orthogonal): all variants of
  3834 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3835 Eps operator is provided as well: "SOME x. P[x]";
  3836 
  3837 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3838 
  3839 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3840 thus available for user theories;
  3841 
  3842 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3843 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3844 time;
  3845 
  3846 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3847 several times and then mp;
  3848 
  3849 
  3850 *** LK ***
  3851 
  3852 * the notation <<...>> is now available as a notation for sequences of
  3853 formulas;
  3854 
  3855 * the simplifier is now installed
  3856 
  3857 * the axiom system has been generalized (thanks to Soren Heilmann)
  3858 
  3859 * the classical reasoner now has a default rule database
  3860 
  3861 
  3862 *** ZF ***
  3863 
  3864 * new primrec section allows primitive recursive functions to be given
  3865 directly (as in HOL) over datatypes and the natural numbers;
  3866 
  3867 * new tactics induct_tac and exhaust_tac for induction (or case
  3868 analysis) over datatypes and the natural numbers;
  3869 
  3870 * the datatype declaration of type T now defines the recursor T_rec;
  3871 
  3872 * simplification automatically does freeness reasoning for datatype
  3873 constructors;
  3874 
  3875 * automatic type-inference, with AddTCs command to insert new
  3876 type-checking rules;
  3877 
  3878 * datatype introduction rules are now added as Safe Introduction rules
  3879 to the claset;
  3880 
  3881 * the syntax "if P then x else y" is now available in addition to
  3882 if(P,x,y);
  3883 
  3884 
  3885 *** Internal programming interfaces ***
  3886 
  3887 * tuned simplifier trace output; new flag debug_simp;
  3888 
  3889 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3890 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3891 
  3892 * AxClass.axclass_tac lost the theory argument;
  3893 
  3894 * tuned current_goals_markers semantics: begin / end goal avoids
  3895 printing empty lines;
  3896 
  3897 * removed prs and prs_fn hook, which was broken because it did not
  3898 include \n in its semantics, forcing writeln to add one
  3899 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3900 string -> unit if you really want to output text without newline;
  3901 
  3902 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3903 plain output, interface builders may have to enable 'isabelle_font'
  3904 mode to get Isabelle font glyphs as before;
  3905 
  3906 * refined token_translation interface; INCOMPATIBILITY: output length
  3907 now of type real instead of int;
  3908 
  3909 * theory loader actions may be traced via new ThyInfo.add_hook
  3910 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3911 your own database of information attached to *whole* theories -- as
  3912 opposed to intra-theory data slots offered via TheoryDataFun;
  3913 
  3914 * proper handling of dangling sort hypotheses (at last!);
  3915 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3916 extra sort hypotheses that can be witnessed from the type signature;
  3917 the force_strip_shyps flag is gone, any remaining shyps are simply
  3918 left in the theorem (with a warning issued by strip_shyps_warning);
  3919 
  3920 
  3921 
  3922 New in Isabelle98-1 (October 1998)
  3923 ----------------------------------
  3924 
  3925 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3926 
  3927 * several changes of automated proof tools;
  3928 
  3929 * HOL: major changes to the inductive and datatype packages, including
  3930 some minor incompatibilities of theory syntax;
  3931 
  3932 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3933 called `inj_on';
  3934 
  3935 * HOL: removed duplicate thms in Arith:
  3936   less_imp_add_less  should be replaced by  trans_less_add1
  3937   le_imp_add_le      should be replaced by  trans_le_add1
  3938 
  3939 * HOL: unary minus is now overloaded (new type constraints may be
  3940 required);
  3941 
  3942 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3943 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3944 now taken as an integer constant.
  3945 
  3946 * Pure: ML function 'theory_of' renamed to 'theory';
  3947 
  3948 
  3949 *** Proof tools ***
  3950 
  3951 * Simplifier:
  3952   1. Asm_full_simp_tac is now more aggressive.
  3953      1. It will sometimes reorient premises if that increases their power to
  3954         simplify.
  3955      2. It does no longer proceed strictly from left to right but may also
  3956         rotate premises to achieve further simplification.
  3957      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3958      old Asm_full_simp_tac in that it does not rotate premises.
  3959   2. The simplifier now knows a little bit about nat-arithmetic.
  3960 
  3961 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3962 allows for selected deletion of wrappers, by introduction of names for
  3963 wrapper functionals.  This implies that addbefore, addSbefore,
  3964 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3965 and that adding two tactics with the same name overwrites the first
  3966 one (emitting a warning).
  3967   type wrapper = (int -> tactic) -> (int -> tactic)
  3968   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3969   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3970   delWrapper, delSWrapper: claset *  string            -> claset
  3971   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3972 
  3973 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3974 semantics; addbefore now affects only the unsafe part of step_tac
  3975 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3976 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3977 by Force_tac;
  3978 
  3979 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3980 compWrapper; added safe wrapper (and access functions for it);
  3981 
  3982 * HOL/split_all_tac is now much faster and fails if there is nothing
  3983 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3984 and the names of the automatically generated variables have changed.
  3985 split_all_tac has moved within claset() from unsafe wrappers to safe
  3986 wrappers, which means that !!-bound variables are split much more
  3987 aggressively, and safe_tac and clarify_tac now split such variables.
  3988 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3989 Note: the same holds for record_split_tac, which does the job of
  3990 split_all_tac for record fields.
  3991 
  3992 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3993 permanently to the default simpset using Addsplits just like
  3994 Addsimps. They can be removed via Delsplits just like
  3995 Delsimps. Lower-case versions are also available.
  3996 
  3997 * HOL/Simplifier: The rule split_if is now part of the default
  3998 simpset. This means that the simplifier will eliminate all occurrences
  3999 of if-then-else in the conclusion of a goal. To prevent this, you can
  4000 either remove split_if completely from the default simpset by
  4001 `Delsplits [split_if]' or remove it in a specific call of the
  4002 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4003 other case splitting rules to/from the default simpset: every datatype
  4004 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4005 t is the name of the datatype).
  4006 
  4007 * Classical reasoner / Simplifier combination: new force_tac (and
  4008 derivatives Force_tac, force) combines rewriting and classical
  4009 reasoning (and whatever other tools) similarly to auto_tac, but is
  4010 aimed to solve the given subgoal completely.
  4011 
  4012 
  4013 *** General ***
  4014 
  4015 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4016 and `goalw': the theory is no longer needed as an explicit argument -
  4017 the current theory context is used; assumptions are no longer returned
  4018 at the ML-level unless one of them starts with ==> or !!; it is
  4019 recommended to convert to these new commands using isatool fixgoal
  4020 (backup your sources first!);
  4021 
  4022 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4023 the current theory context, and 'theory' to lookup stored theories;
  4024 
  4025 * new theory section 'locale' for declaring constants, assumptions and
  4026 definitions that have local scope;
  4027 
  4028 * new theory section 'nonterminals' for purely syntactic types;
  4029 
  4030 * new theory section 'setup' for generic ML setup functions
  4031 (e.g. package initialization);
  4032 
  4033 * the distribution now includes Isabelle icons: see
  4034 lib/logo/isabelle-{small,tiny}.xpm;
  4035 
  4036 * isatool install - install binaries with absolute references to
  4037 ISABELLE_HOME/bin;
  4038 
  4039 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4040 
  4041 * print mode 'emacs' reserved for Isamode;
  4042 
  4043 * support multiple print (ast) translations per constant name;
  4044 
  4045 * theorems involving oracles are now printed with a suffixed [!];
  4046 
  4047 
  4048 *** HOL ***
  4049 
  4050 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4051 
  4052 * HOL/inductive package reorganized and improved: now supports mutual
  4053 definitions such as
  4054 
  4055   inductive EVEN ODD
  4056     intrs
  4057       null "0 : EVEN"
  4058       oddI "n : EVEN ==> Suc n : ODD"
  4059       evenI "n : ODD ==> Suc n : EVEN"
  4060 
  4061 new theorem list "elims" contains an elimination rule for each of the
  4062 recursive sets; inductive definitions now handle disjunctive premises
  4063 correctly (also ZF);
  4064 
  4065 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4066 "mutual_induct" no longer exists - the induction rule is always
  4067 contained in "induct";
  4068 
  4069 
  4070 * HOL/datatype package re-implemented and greatly improved: now
  4071 supports mutually recursive datatypes such as
  4072 
  4073   datatype
  4074     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4075             | SUM ('a aexp) ('a aexp)
  4076             | DIFF ('a aexp) ('a aexp)
  4077             | NUM 'a
  4078   and
  4079     'a bexp = LESS ('a aexp) ('a aexp)
  4080             | AND ('a bexp) ('a bexp)
  4081             | OR ('a bexp) ('a bexp)
  4082 
  4083 as well as indirectly recursive datatypes such as
  4084 
  4085   datatype
  4086     ('a, 'b) term = Var 'a
  4087                   | App 'b ((('a, 'b) term) list)
  4088 
  4089 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4090 induction on mutually / indirectly recursive datatypes.
  4091 
  4092 Primrec equations are now stored in theory and can be accessed via
  4093 <function_name>.simps.
  4094 
  4095 INCOMPATIBILITIES:
  4096 
  4097   - Theories using datatypes must now have theory Datatype as an
  4098     ancestor.
  4099   - The specific <typename>.induct_tac no longer exists - use the
  4100     generic induct_tac instead.
  4101   - natE has been renamed to nat.exhaust - use exhaust_tac
  4102     instead of res_inst_tac ... natE. Note that the variable
  4103     names in nat.exhaust differ from the names in natE, this
  4104     may cause some "fragile" proofs to fail.
  4105   - The theorems split_<typename>_case and split_<typename>_case_asm
  4106     have been renamed to <typename>.split and <typename>.split_asm.
  4107   - Since default sorts of type variables are now handled correctly,
  4108     some datatype definitions may have to be annotated with explicit
  4109     sort constraints.
  4110   - Primrec definitions no longer require function name and type
  4111     of recursive argument.
  4112 
  4113 Consider using isatool fixdatatype to adapt your theories and proof
  4114 scripts to the new package (backup your sources first!).
  4115 
  4116 
  4117 * HOL/record package: considerably improved implementation; now
  4118 includes concrete syntax for record types, terms, updates; theorems
  4119 for surjective pairing and splitting !!-bound record variables; proof
  4120 support is as follows:
  4121 
  4122   1) standard conversions (selectors or updates applied to record
  4123 constructor terms) are part of the standard simpset;
  4124 
  4125   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4126 made part of standard simpset and claset via addIffs;
  4127 
  4128   3) a tactic for record field splitting (record_split_tac) is part of
  4129 the standard claset (addSWrapper);
  4130 
  4131 To get a better idea about these rules you may retrieve them via
  4132 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4133 the name of your record type.
  4134 
  4135 The split tactic 3) conceptually simplifies by the following rule:
  4136 
  4137   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4138 
  4139 Thus any record variable that is bound by meta-all will automatically
  4140 blow up into some record constructor term, consequently the
  4141 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4142 solve record problems automatically.
  4143 
  4144 
  4145 * reorganized the main HOL image: HOL/Integ and String loaded by
  4146 default; theory Main includes everything;
  4147 
  4148 * automatic simplification of integer sums and comparisons, using cancellation;
  4149 
  4150 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4151 
  4152 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4153 
  4154 * many new identities for unions, intersections, set difference, etc.;
  4155 
  4156 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4157 called split_if, split_split, split_sum_case and split_nat_case (to go
  4158 with add/delsplits);
  4159 
  4160 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4161 (?x::unit) = (); this is made part of the default simpset, which COULD
  4162 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4163 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4164 unit_abs_eta_conv is added in order to counter the effect of
  4165 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4166 %u.f();
  4167 
  4168 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4169 makes more sense);
  4170 
  4171 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4172   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4173   disjointness reasoning but breaking a few old proofs.
  4174 
  4175 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4176 to 'converse' from 'inverse' (for compatibility with ZF and some
  4177 literature);
  4178 
  4179 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4180 the well-founded relation;
  4181 
  4182 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4183     Compl A.  The "Compl" syntax remains available as input syntax for this
  4184     release ONLY.
  4185 
  4186 * HOL/Update: new theory of function updates:
  4187     f(a:=b) == %x. if x=a then b else f x
  4188 may also be iterated as in f(a:=b,c:=d,...);
  4189 
  4190 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4191 
  4192 * HOL/List:
  4193   - new function list_update written xs[i:=v] that updates the i-th
  4194     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4195   - new function `upt' written [i..j(] which generates the list
  4196     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4197     bound write [i..j], which is a shorthand for [i..j+1(].
  4198   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4199 
  4200 * HOL/Arith:
  4201   - removed 'pred' (predecessor) function;
  4202   - generalized some theorems about n-1;
  4203   - many new laws about "div" and "mod";
  4204   - new laws about greatest common divisors (see theory ex/Primes);
  4205 
  4206 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4207 instead of "inverse";
  4208 
  4209 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4210   of the multiset ordering;
  4211 
  4212 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4213   (not included by default);
  4214 
  4215 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4216 
  4217 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4218   programs, i.e. different program variables may have different types.
  4219 
  4220 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4221   [previously, this check worked only if the rewrite rule was unconditional]
  4222   Now rew can involve either definitions or equalities (either == or =).
  4223 
  4224 
  4225 *** ZF ***
  4226 
  4227 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4228   only the theorems proved on ZF.ML;
  4229 
  4230 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4231   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4232   disjointness reasoning but breaking a few old proofs.
  4233 
  4234 * ZF/Update: new theory of function updates
  4235     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4236   may also be iterated as in f(a:=b,c:=d,...);
  4237 
  4238 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4239 
  4240 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4241   [previously, this check worked only if the rewrite rule was unconditional]
  4242   Now rew can involve either definitions or equalities (either == or =).
  4243 
  4244 * case_tac provided for compatibility with HOL
  4245     (like the old excluded_middle_tac, but with subgoals swapped)
  4246 
  4247 
  4248 *** Internal programming interfaces ***
  4249 
  4250 * Pure: several new basic modules made available for general use, see
  4251 also src/Pure/README;
  4252 
  4253 * improved the theory data mechanism to support encapsulation (data
  4254 kind name replaced by private Object.kind, acting as authorization
  4255 key); new type-safe user interface via functor TheoryDataFun; generic
  4256 print_data function becomes basically useless;
  4257 
  4258 * removed global_names compatibility flag -- all theory declarations
  4259 are qualified by default;
  4260 
  4261 * module Pure/Syntax now offers quote / antiquote translation
  4262 functions (useful for Hoare logic etc. with implicit dependencies);
  4263 see HOL/ex/Antiquote for an example use;
  4264 
  4265 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4266 cterm -> thm;
  4267 
  4268 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4269 subgoal;
  4270 
  4271 * Display.print_goals function moved to Locale.print_goals;
  4272 
  4273 * standard print function for goals supports current_goals_markers
  4274 variable for marking begin of proof, end of proof, start of goal; the
  4275 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4276 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4277 for example;
  4278 
  4279 
  4280 
  4281 New in Isabelle98 (January 1998)
  4282 --------------------------------
  4283 
  4284 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4285 
  4286 * changed lexical syntax of terms / types: dots made part of long
  4287 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4288 
  4289 * simpset (and claset) reference variable replaced by functions
  4290 simpset / simpset_ref;
  4291 
  4292 * no longer supports theory aliases (via merge) and non-trivial
  4293 implicit merge of thms' signatures;
  4294 
  4295 * most internal names of constants changed due to qualified names;
  4296 
  4297 * changed Pure/Sequence interface (see Pure/seq.ML);
  4298 
  4299 
  4300 *** General Changes ***
  4301 
  4302 * hierachically structured name spaces (for consts, types, axms, thms
  4303 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4304 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4305 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4306 long_names for fully qualified output names; NOTE: ML programs
  4307 (special tactics, packages etc.) referring to internal names may have
  4308 to be adapted to cope with fully qualified names; in case of severe
  4309 backward campatibility problems try setting 'global_names' at compile
  4310 time to have enrything declared within a flat name space; one may also
  4311 fine tune name declarations in theories via the 'global' and 'local'
  4312 section;
  4313 
  4314 * reimplemented the implicit simpset and claset using the new anytype
  4315 data filed in signatures; references simpset:simpset ref etc. are
  4316 replaced by functions simpset:unit->simpset and
  4317 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4318 to patch your ML files accordingly;
  4319 
  4320 * HTML output now includes theory graph data for display with Java
  4321 applet or isatool browser; data generated automatically via isatool
  4322 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4323 
  4324 * defs may now be conditional; improved rewrite_goals_tac to handle
  4325 conditional equations;
  4326 
  4327 * defs now admits additional type arguments, using TYPE('a) syntax;
  4328 
  4329 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4330 creates a new theory node; implicit merge of thms' signatures is
  4331 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4332 transfer:theory->thm->thm in (rare) cases;
  4333 
  4334 * improved handling of draft signatures / theories; draft thms (and
  4335 ctyps, cterms) are automatically promoted to real ones;
  4336 
  4337 * slightly changed interfaces for oracles: admit many per theory, named
  4338 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4339 
  4340 * print_goals: optional output of const types (set show_consts and
  4341 show_types);
  4342 
  4343 * improved output of warnings (###) and errors (***);
  4344 
  4345 * subgoal_tac displays a warning if the new subgoal has type variables;
  4346 
  4347 * removed old README and Makefiles;
  4348 
  4349 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4350 
  4351 * removed obsolete init_pps and init_database;
  4352 
  4353 * deleted the obsolete tactical STATE, which was declared by
  4354     fun STATE tacfun st = tacfun st st;
  4355 
  4356 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4357 (which abbreviates $HOME);
  4358 
  4359 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4360 use isatool fixseq to adapt your ML programs (this works for fully
  4361 qualified references to the Sequence structure only!);
  4362 
  4363 * use_thy no longer requires writable current directory; it always
  4364 reloads .ML *and* .thy file, if either one is out of date;
  4365 
  4366 
  4367 *** Classical Reasoner ***
  4368 
  4369 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4370 tactics that use classical reasoning to simplify a subgoal without
  4371 splitting it into several subgoals;
  4372 
  4373 * Safe_tac: like safe_tac but uses the default claset;
  4374 
  4375 
  4376 *** Simplifier ***
  4377 
  4378 * added simplification meta rules:
  4379     (asm_)(full_)simplify: simpset -> thm -> thm;
  4380 
  4381 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4382 logics (again);
  4383 
  4384 * added prems argument to simplification procedures;
  4385 
  4386 * HOL, FOL, ZF: added infix function `addsplits':
  4387   instead of `<simpset> setloop (split_tac <thms>)'
  4388   you can simply write `<simpset> addsplits <thms>'
  4389 
  4390 
  4391 *** Syntax ***
  4392 
  4393 * TYPE('a) syntax for type reflection terms;
  4394 
  4395 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4396 
  4397 * pretty printer: changed order of mixfix annotation preference (again!);
  4398 
  4399 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4400 
  4401 
  4402 *** HOL ***
  4403 
  4404 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4405   with `addloop' of the simplifier to faciliate case splitting in premises.
  4406 
  4407 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4408 
  4409 * HOL/Auth: new protocol proofs including some for the Internet
  4410   protocol TLS;
  4411 
  4412 * HOL/Map: new theory of `maps' a la VDM;
  4413 
  4414 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4415 cancelling out common nat summands from =, <, <= (in)equalities, or
  4416 differences; simplification procedures nat_cancel_factor for
  4417 cancelling common factor from =, <, <= (in)equalities over natural
  4418 sums; nat_cancel contains both kinds of procedures, it is installed by
  4419 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4420 
  4421 * HOL/simplifier: terms of the form
  4422   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4423   are rewritten to
  4424   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4425   and those of the form
  4426   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4427   are rewritten to
  4428   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4429 
  4430 * HOL/datatype
  4431   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4432 
  4433   P(t_case f1 ... fn x) =
  4434      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4435         ...
  4436        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4437      )
  4438 
  4439   and a theorem `split_t_case_asm' of the form
  4440 
  4441   P(t_case f1 ... fn x) =
  4442     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4443         ...
  4444        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4445      )
  4446   which can be added to a simpset via `addsplits'. The existing theorems
  4447   expand_list_case and expand_option_case have been renamed to
  4448   split_list_case and split_option_case.
  4449 
  4450 * HOL/Arithmetic:
  4451   - `pred n' is automatically converted to `n-1'.
  4452     Users are strongly encouraged not to use `pred' any longer,
  4453     because it will disappear altogether at some point.
  4454   - Users are strongly encouraged to write "0 < n" rather than
  4455     "n ~= 0". Theorems and proof tools have been modified towards this
  4456     `standard'.
  4457 
  4458 * HOL/Lists:
  4459   the function "set_of_list" has been renamed "set" (and its theorems too);
  4460   the function "nth" now takes its arguments in the reverse order and
  4461   has acquired the infix notation "!" as in "xs!n".
  4462 
  4463 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4464 
  4465 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4466   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4467 
  4468 * HOL/record: extensible records with schematic structural subtyping
  4469 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4470 still lacks various theorems and concrete record syntax;
  4471 
  4472 
  4473 *** HOLCF ***
  4474 
  4475 * removed "axioms" and "generated by" sections;
  4476 
  4477 * replaced "ops" section by extended "consts" section, which is capable of
  4478   handling the continuous function space "->" directly;
  4479 
  4480 * domain package:
  4481   . proves theorems immediately and stores them in the theory,
  4482   . creates hierachical name space,
  4483   . now uses normal mixfix annotations (instead of cinfix...),
  4484   . minor changes to some names and values (for consistency),
  4485   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4486   . separator between mutual domain defs: changed "," to "and",
  4487   . improved handling of sort constraints;  now they have to
  4488     appear on the left-hand side of the equations only;
  4489 
  4490 * fixed LAM <x,y,zs>.b syntax;
  4491 
  4492 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4493 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4494 
  4495 
  4496 *** FOL and ZF ***
  4497 
  4498 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4499   with `addloop' of the simplifier to faciliate case splitting in premises.
  4500 
  4501 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4502 in HOL, they strip ALL and --> from proved theorems;
  4503 
  4504 
  4505 
  4506 New in Isabelle94-8 (May 1997)
  4507 ------------------------------
  4508 
  4509 *** General Changes ***
  4510 
  4511 * new utilities to build / run / maintain Isabelle etc. (in parts
  4512 still somewhat experimental); old Makefiles etc. still functional;
  4513 
  4514 * new 'Isabelle System Manual';
  4515 
  4516 * INSTALL text, together with ./configure and ./build scripts;
  4517 
  4518 * reimplemented type inference for greater efficiency, better error
  4519 messages and clean internal interface;
  4520 
  4521 * prlim command for dealing with lots of subgoals (an easier way of
  4522 setting goals_limit);
  4523 
  4524 
  4525 *** Syntax ***
  4526 
  4527 * supports alternative (named) syntax tables (parser and pretty
  4528 printer); internal interface is provided by add_modesyntax(_i);
  4529 
  4530 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4531 be used in conjunction with the Isabelle symbol font; uses the
  4532 "symbols" syntax table;
  4533 
  4534 * added token_translation interface (may translate name tokens in
  4535 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4536 the current print_mode); IMPORTANT: user print translation functions
  4537 are responsible for marking newly introduced bounds
  4538 (Syntax.mark_boundT);
  4539 
  4540 * token translations for modes "xterm" and "xterm_color" that display
  4541 names in bold, underline etc. or colors (which requires a color
  4542 version of xterm);
  4543 
  4544 * infixes may now be declared with names independent of their syntax;
  4545 
  4546 * added typed_print_translation (like print_translation, but may
  4547 access type of constant);
  4548 
  4549 
  4550 *** Classical Reasoner ***
  4551 
  4552 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4553 some limitations.  Blast_tac...
  4554   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4555   + ignores elimination rules that don't have the correct format
  4556         (the conclusion MUST be a formula variable)
  4557   + ignores types, which can make HOL proofs fail
  4558   + rules must not require higher-order unification, e.g. apply_type in ZF
  4559     [message "Function Var's argument not a bound variable" relates to this]
  4560   + its proof strategy is more general but can actually be slower
  4561 
  4562 * substitution with equality assumptions no longer permutes other
  4563 assumptions;
  4564 
  4565 * minor changes in semantics of addafter (now called addaltern); renamed
  4566 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4567 (and access functions for it);
  4568 
  4569 * improved combination of classical reasoner and simplifier:
  4570   + functions for handling clasimpsets
  4571   + improvement of addss: now the simplifier is called _after_ the
  4572     safe steps.
  4573   + safe variant of addss called addSss: uses safe simplifications
  4574     _during_ the safe steps. It is more complete as it allows multiple
  4575     instantiations of unknowns (e.g. with slow_tac).
  4576 
  4577 *** Simplifier ***
  4578 
  4579 * added interface for simplification procedures (functions that
  4580 produce *proven* rewrite rules on the fly, depending on current
  4581 redex);
  4582 
  4583 * ordering on terms as parameter (used for ordered rewriting);
  4584 
  4585 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4586 
  4587 * the solver is now split into a safe and an unsafe part.
  4588 This should be invisible for the normal user, except that the
  4589 functions setsolver and addsolver have been renamed to setSolver and
  4590 addSolver; added safe_asm_full_simp_tac;
  4591 
  4592 
  4593 *** HOL ***
  4594 
  4595 * a generic induction tactic `induct_tac' which works for all datatypes and
  4596 also for type `nat';
  4597 
  4598 * a generic case distinction tactic `exhaust_tac' which works for all
  4599 datatypes and also for type `nat';
  4600 
  4601 * each datatype comes with a function `size';
  4602 
  4603 * patterns in case expressions allow tuple patterns as arguments to
  4604 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4605 
  4606 * primrec now also works with type nat;
  4607 
  4608 * recdef: a new declaration form, allows general recursive functions to be
  4609 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4610 
  4611 * the constant for negation has been renamed from "not" to "Not" to
  4612 harmonize with FOL, ZF, LK, etc.;
  4613 
  4614 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4615 infinite lists;
  4616 
  4617 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4618 
  4619 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4620 problems in commutative rings, using axiomatic type classes for + and *;
  4621 
  4622 * more examples in HOL/MiniML and HOL/Auth;
  4623 
  4624 * more default rewrite rules for quantifiers, union/intersection;
  4625 
  4626 * a new constant `arbitrary == @x.False';
  4627 
  4628 * HOLCF/IOA replaces old HOL/IOA;
  4629 
  4630 * HOLCF changes: derived all rules and arities
  4631   + axiomatic type classes instead of classes
  4632   + typedef instead of faking type definitions
  4633   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4634   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4635   + eliminated the types void, one, tr
  4636   + use unit lift and bool lift (with translations) instead of one and tr
  4637   + eliminated blift from Lift3.thy (use Def instead of blift)
  4638   all eliminated rules are derived as theorems --> no visible changes ;
  4639 
  4640 
  4641 *** ZF ***
  4642 
  4643 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4644 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4645 as ZF_cs addSIs [equalityI];
  4646 
  4647 
  4648 
  4649 New in Isabelle94-7 (November 96)
  4650 ---------------------------------
  4651 
  4652 * allowing negative levels (as offsets) in prlev and choplev;
  4653 
  4654 * super-linear speedup for large simplifications;
  4655 
  4656 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4657 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4658 FAIL); can suppress it using the command Delsimps (ex_simps @
  4659 all_simps); De Morgan laws are also now included, by default;
  4660 
  4661 * improved printing of ==>  :  ~:
  4662 
  4663 * new object-logic "Sequents" adds linear logic, while replacing LK
  4664 and Modal (thanks to Sara Kalvala);
  4665 
  4666 * HOL/Auth: correctness proofs for authentication protocols;
  4667 
  4668 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4669 examples on HOL/Auth);
  4670 
  4671 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4672 the rewriter and classical reasoner simultaneously;
  4673 
  4674 * function uresult no longer returns theorems in "standard" format;
  4675 regain previous version by: val uresult = standard o uresult;
  4676 
  4677 
  4678 
  4679 New in Isabelle94-6
  4680 -------------------
  4681 
  4682 * oracles -- these establish an interface between Isabelle and trusted
  4683 external reasoners, which may deliver results as theorems;
  4684 
  4685 * proof objects (in particular record all uses of oracles);
  4686 
  4687 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4688 
  4689 * "constdefs" section in theory files;
  4690 
  4691 * "primrec" section (HOL) no longer requires names;
  4692 
  4693 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4694 
  4695 
  4696 
  4697 New in Isabelle94-5
  4698 -------------------
  4699 
  4700 * reduced space requirements;
  4701 
  4702 * automatic HTML generation from theories;
  4703 
  4704 * theory files no longer require "..." (quotes) around most types;
  4705 
  4706 * new examples, including two proofs of the Church-Rosser theorem;
  4707 
  4708 * non-curried (1994) version of HOL is no longer distributed;
  4709 
  4710 
  4711 
  4712 New in Isabelle94-4
  4713 -------------------
  4714 
  4715 * greatly reduced space requirements;
  4716 
  4717 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4718 
  4719 * searchable theorem database (see the section "Retrieving theorems" on
  4720 page 8 of the Reference Manual);
  4721 
  4722 * new examples, including Grabczewski's monumental case study of the
  4723 Axiom of Choice;
  4724 
  4725 * The previous version of HOL renamed to Old_HOL;
  4726 
  4727 * The new version of HOL (previously called CHOL) uses a curried syntax
  4728 for functions.  Application looks like f a b instead of f(a,b);
  4729 
  4730 * Mutually recursive inductive definitions finally work in HOL;
  4731 
  4732 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4733 translates to the operator "split";
  4734 
  4735 
  4736 
  4737 New in Isabelle94-3
  4738 -------------------
  4739 
  4740 * new infix operator, addss, allowing the classical reasoner to
  4741 perform simplification at each step of its search.  Example:
  4742         fast_tac (cs addss ss)
  4743 
  4744 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4745 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4746 look like (a,b) instead of <a,b>;
  4747 
  4748 * PLEASE NOTE: CHOL will eventually replace HOL!
  4749 
  4750 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4751 It translates to the operator "split".  A new theory of integers is available;
  4752 
  4753 * In ZF, integer numerals now denote two's-complement binary integers.
  4754 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4755 
  4756 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4757 of the Axiom of Choice;
  4758 
  4759 
  4760 
  4761 New in Isabelle94-2
  4762 -------------------
  4763 
  4764 * Significantly faster resolution;
  4765 
  4766 * the different sections in a .thy file can now be mixed and repeated
  4767 freely;
  4768 
  4769 * Database of theorems for FOL, HOL and ZF.  New
  4770 commands including qed, qed_goal and bind_thm store theorems in the database.
  4771 
  4772 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4773 a given theory (thms_of), or find out what theory a theorem was proved in
  4774 (theory_of_thm);
  4775 
  4776 * Bugs fixed in the inductive definition and datatype packages;
  4777 
  4778 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4779 and HOL_dup_cs obsolete;
  4780 
  4781 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4782 have been removed;
  4783 
  4784 * Simpler definition of function space in ZF;
  4785 
  4786 * new results about cardinal and ordinal arithmetic in ZF;
  4787 
  4788 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4789 types;
  4790 
  4791 
  4792 $Id$