NEWS
author nipkow
Fri May 25 18:24:11 2007 +0200 (2007-05-25)
changeset 23104 0a47a5681704
parent 23103 b00e7ce9dcdc
child 23116 16e1401afe91
permissions -rw-r--r--
*** empty log message ***
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * More uniform information about legacy features, notably a
    10 warning/error of "Legacy feature: ...", depending on the state of the
    11 tolerate_legacy_features flag (default true).
    12 
    13 * Theory syntax: the header format ``theory A = B + C:'' has been
    14 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    15 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    16 
    17 * Theory syntax: the old non-Isar theory file format has been
    18 discontinued altogether.  Note that ML proof scripts may still be used
    19 with Isar theories; migration is usually quite simple with the ML
    20 function use_legacy_bindings.  INCOMPATIBILITY.
    21 
    22 * Theory syntax: some popular names (e.g. 'class', 'declaration',
    23 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
    24 quotes.
    25 
    26 * Legacy goal package: reduced interface to the bare minimum required
    27 to keep existing proof scripts running.  Most other user-level
    28 functions are now part of the OldGoals structure, which is *not* open
    29 by default (consider isatool expandshort before open OldGoals).
    30 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    31 these tend to cause confusion about the actual goal (!) context being
    32 used here, which is not necessarily the same as the_context().
    33 
    34 * Command 'find_theorems': support "*" wildcard in "name:" criterion.
    35 
    36 * Proof General interface: A search form for the "Find Theorems" command is
    37 now available via C-c C-a C-f.  The old minibuffer interface is available
    38 via C-c C-a C-m.  Variable proof-find-theorems-command (customizable via
    39 'Proof-General -> Advanced -> Internals -> Prover Config') controls the
    40 default behavior of 'ProofGeneral -> Find Theorems' (C-c C-f): set to
    41 isar-find-theorems-form or isar-find-theorems-minibuffer.
    42 
    43 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    44 by default, which means that "prems" (and also "fixed variables") are
    45 suppressed from proof state output.  Note that the ProofGeneral
    46 settings mechanism allows to change and save options persistently, but
    47 older versions of Isabelle will fail to start up if a negative prems
    48 limit is imposed.
    49 
    50 * Local theory targets may be specified by non-nested blocks of
    51 ``context/locale/class ... begin'' followed by ``end''.  The body may
    52 contain definitions, theorems etc., including any derived mechanism
    53 that has been implemented on top of these primitives.  This concept
    54 generalizes the existing ``theorem (in ...)'' towards more versatility
    55 and scalability.
    56 
    57 * Proof General interface: proper undo of final 'end' command;
    58 discontinued Isabelle/classic mode (ML proof scripts).
    59 
    60 
    61 *** Document preparation ***
    62 
    63 * Added antiquotation @{theory name} which prints the given name,
    64 after checking that it refers to a valid ancestor theory in the
    65 current context.
    66 
    67 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    68 check the given source text as ML type/structure, printing verbatim.
    69 
    70 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    71 "c args == rhs" given in the current context.  (Any number of
    72 arguments may be given on the LHS.)
    73 
    74 
    75 
    76 *** Pure ***
    77 
    78 * code generator: consts in 'consts_code' Isar commands are now referred
    79   to by usual term syntax (including optional type annotations).
    80 
    81 * code generator: 
    82   - Isar 'definition's, 'constdef's and primitive instance definitions are added
    83     explicitly to the table of defining equations
    84   - primitive definitions are not used as defining equations by default any longer
    85   - defining equations are now definitly restricted to meta "==" and object
    86         equality "="
    87   - HOL theories have been adopted accordingly
    88 
    89 * class_package.ML offers a combination of axclasses and locales to
    90 achieve Haskell-like type classes in Isabelle.  See
    91 HOL/ex/Classpackage.thy for examples.
    92 
    93 * Yet another code generator framework allows to generate executable
    94 code for ML and Haskell (including "class"es).  A short usage sketch:
    95 
    96     internal compilation:
    97         code_gen <list of constants (term syntax)> (SML #)
    98     writing SML code to a file:
    99         code_gen <list of constants (term syntax)> (SML <filename>)
   100     writing OCaml code to a file:
   101         code_gen <list of constants (term syntax)> (OCaml <filename>)
   102     writing Haskell code to a bunch of files:
   103         code_gen <list of constants (term syntax)> (Haskell <filename>)
   104 
   105 Reasonable default setup of framework in HOL/Main.
   106 
   107 Theorem attributs for selecting and transforming function equations theorems:
   108 
   109     [code fun]:        select a theorem as function equation for a specific constant
   110     [code fun del]:    deselect a theorem as function equation for a specific constant
   111     [code inline]:     select an equation theorem for unfolding (inlining) in place
   112     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   113 
   114 User-defined serializations (target in {SML, OCaml, Haskell}):
   115 
   116     code_const <and-list of constants (term syntax)>
   117       {(target) <and-list of const target syntax>}+
   118 
   119     code_type <and-list of type constructors>
   120       {(target) <and-list of type target syntax>}+
   121 
   122     code_instance <and-list of instances>
   123       {(target)}+
   124         where instance ::= <type constructor> :: <class>
   125 
   126     code_class <and_list of classes>
   127       {(target) <and-list of class target syntax>}+
   128         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   129 
   130 code_instance and code_class only apply to target Haskell.
   131 
   132 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   133 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   134 
   135 * Command 'no_translations' removes translation rules from theory
   136 syntax.
   137 
   138 * Overloaded definitions are now actually checked for acyclic
   139 dependencies.  The overloading scheme is slightly more general than
   140 that of Haskell98, although Isabelle does not demand an exact
   141 correspondence to type class and instance declarations.
   142 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   143 exotic versions of overloading -- at the discretion of the user!
   144 
   145 Polymorphic constants are represented via type arguments, i.e. the
   146 instantiation that matches an instance against the most general
   147 declaration given in the signature.  For example, with the declaration
   148 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   149 as c(nat).  Overloading is essentially simultaneous structural
   150 recursion over such type arguments.  Incomplete specification patterns
   151 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   152 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   153 Command 'print_theory' outputs the normalized system of recursive
   154 equations, see section "definitions".
   155 
   156 * Isar: improper proof element 'guess' is like 'obtain', but derives
   157 the obtained context from the course of reasoning!  For example:
   158 
   159   assume "EX x y. A x & B y"   -- "any previous fact"
   160   then guess x and y by clarify
   161 
   162 This technique is potentially adventurous, depending on the facts and
   163 proof tools being involved here.
   164 
   165 * Isar: known facts from the proof context may be specified as literal
   166 propositions, using ASCII back-quote syntax.  This works wherever
   167 named facts used to be allowed so far, in proof commands, proof
   168 methods, attributes etc.  Literal facts are retrieved from the context
   169 according to unification of type and term parameters.  For example,
   170 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   171 theorems in the current context, then these are valid literal facts:
   172 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   173 
   174 There is also a proof method "fact" which does the same composition
   175 for explicit goal states, e.g. the following proof texts coincide with
   176 certain special cases of literal facts:
   177 
   178   have "A" by fact                 ==  note `A`
   179   have "A ==> B" by fact           ==  note `A ==> B`
   180   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   181   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   182 
   183 * Isar: ":" (colon) is no longer a symbolic identifier character in
   184 outer syntax.  Thus symbolic identifiers may be used without
   185 additional white space in declarations like this: ``assume *: A''.
   186 
   187 * Isar: 'print_facts' prints all local facts of the current context,
   188 both named and unnamed ones.
   189 
   190 * Isar: 'def' now admits simultaneous definitions, e.g.:
   191 
   192   def x == "t" and y == "u"
   193 
   194 * Isar: added command 'unfolding', which is structurally similar to
   195 'using', but affects both the goal state and facts by unfolding given
   196 rewrite rules.  Thus many occurrences of the 'unfold' method or
   197 'unfolded' attribute may be replaced by first-class proof text.
   198 
   199 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   200 and command 'unfolding' now all support object-level equalities
   201 (potentially conditional).  The underlying notion of rewrite rule is
   202 analogous to the 'rule_format' attribute, but *not* that of the
   203 Simplifier (which is usually more generous).
   204 
   205 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   206 method expression within a sandbox consisting of the first N
   207 sub-goals, which need to exist.  For example, ``simp_all [3]''
   208 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   209 simplifies all new goals that emerge from applying rule foo to the
   210 originally first one.
   211 
   212 * Isar: schematic goals are no longer restricted to higher-order
   213 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   214 expected.
   215 
   216 * Isar: the conclusion of a long theorem statement is now either
   217 'shows' (a simultaneous conjunction, as before), or 'obtains'
   218 (essentially a disjunction of cases with local parameters and
   219 assumptions).  The latter allows to express general elimination rules
   220 adequately; in this notation common elimination rules look like this:
   221 
   222   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   223     assumes "EX x. P x"
   224     obtains x where "P x"
   225 
   226   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   227     assumes "A & B"
   228     obtains A and B
   229 
   230   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   231     assumes "A | B"
   232     obtains
   233       A
   234     | B
   235 
   236 The subsequent classical rules even refer to the formal "thesis"
   237 explicitly:
   238 
   239   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   240     obtains "~ thesis"
   241 
   242   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   243     obtains "thesis ==> something"
   244 
   245 The actual proof of an 'obtains' statement is analogous to that of the
   246 Isar proof element 'obtain', only that there may be several cases.
   247 Optional case names may be specified in parentheses; these will be
   248 available both in the present proof and as annotations in the
   249 resulting rule, for later use with the 'cases' method (cf. attribute
   250 case_names).
   251 
   252 * Isar: the assumptions of a long theorem statement are available as
   253 "assms" fact in the proof context.  This is more appropriate than the
   254 (historical) "prems", which refers to all assumptions of the current
   255 context, including those from the target locale, proof body etc.
   256 
   257 * Isar: 'print_statement' prints theorems from the current theory or
   258 proof context in long statement form, according to the syntax of a
   259 top-level lemma.
   260 
   261 * Isar: 'obtain' takes an optional case name for the local context
   262 introduction rule (default "that").
   263 
   264 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   265 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   266 to occur.
   267 
   268 * Pure: syntax "CONST name" produces a fully internalized constant
   269 according to the current context.  This is particularly useful for
   270 syntax translations that should refer to internal constant
   271 representations independently of name spaces.
   272 
   273 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   274 instead of "FOO ". This allows multiple binder declarations to coexist
   275 in the same context.  INCOMPATIBILITY.
   276 
   277 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   278 primitive that also works in a locale context (both for constants and
   279 fixed variables).  Type declaration and internal syntactic
   280 representation of given constants retrieved from the context.
   281 
   282 * Isar/locales: new derived specification elements 'axiomatization',
   283 'definition', 'abbreviation', which support type-inference, admit
   284 object-level specifications (equality, equivalence).  See also the
   285 isar-ref manual.  Examples:
   286 
   287   axiomatization
   288     eq  (infix "===" 50) where
   289     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   290 
   291   definition "f x y = x + y + 1"
   292   definition g where "g x = f x x"
   293 
   294   abbreviation
   295     neq  (infix "=!=" 50) where
   296     "x =!= y == ~ (x === y)"
   297 
   298 These specifications may be also used in a locale context.  Then the
   299 constants being introduced depend on certain fixed parameters, and the
   300 constant name is qualified by the locale base name.  An internal
   301 abbreviation takes care for convenient input and output, making the
   302 parameters implicit and using the original short name.  See also
   303 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   304 entities from a monomorphic theory.
   305 
   306 Presently, abbreviations are only available 'in' a target locale, but
   307 not inherited by general import expressions.  Also note that
   308 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   309 'translations' in common applications.
   310 
   311 Concrete syntax is attached to specified constants in internal form,
   312 independently of name spaces.  The parse tree representation is
   313 slightly different -- use 'notation' instead of raw 'syntax', and
   314 'translations' with explicit "CONST" markup to accommodate this.
   315 
   316 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   317 the current context.  Print mode "no_abbrevs" prevents inversion of
   318 abbreviations on output.
   319 
   320 * Isar/locales: improved parameter handling:
   321 - use of locales "var" and "struct" no longer necessary;
   322 - parameter renamings are no longer required to be injective.
   323   This enables, for example, to define a locale for endomorphisms thus:
   324   locale endom = homom mult mult h.
   325 
   326 * Isar/locales: changed the way locales with predicates are defined.
   327 Instead of accumulating the specification, the imported expression is
   328 now an interpretation.  INCOMPATIBILITY: different normal form of
   329 locale expressions.  In particular, in interpretations of locales with
   330 predicates, goals repesenting already interpreted fragments are not
   331 removed automatically.  Use methods `intro_locales' and
   332 `unfold_locales'; see below.
   333 
   334 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   335 provide backward reasoning on locales predicates.  The methods are
   336 aware of interpretations and discharge corresponding goals.
   337 `intro_locales' is less aggressive then `unfold_locales' and does not
   338 unfold predicates to assumptions.
   339 
   340 * Isar/locales: the order in which locale fragments are accumulated
   341 has changed.  This enables to override declarations from fragments due
   342 to interpretations -- for example, unwanted simp rules.
   343 
   344 * Provers/induct: improved internal context management to support
   345 local fixes and defines on-the-fly.  Thus explicit meta-level
   346 connectives !! and ==> are rarely required anymore in inductive goals
   347 (using object-logic connectives for this purpose has been long
   348 obsolete anyway).  The subsequent proof patterns illustrate advanced
   349 techniques of natural induction; general datatypes and inductive sets
   350 work analogously (see also src/HOL/Lambda for realistic examples).
   351 
   352 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   353 parameters:
   354 
   355   lemma
   356     fixes n :: nat and x :: 'a
   357     assumes a: "A n x"
   358     shows "P n x"
   359     using a                     -- {* make induct insert fact a *}
   360   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   361     case 0
   362     show ?case sorry
   363   next
   364     case (Suc n)
   365     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   366     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   367     show ?case sorry
   368   qed
   369 
   370 (2) This is how to perform induction over ``expressions of a certain
   371 form'', using a locally defined inductive parameter n == "a x"
   372 together with strengthening (the latter is usually required to get
   373 sufficiently flexible induction hypotheses):
   374 
   375   lemma
   376     fixes a :: "'a => nat"
   377     assumes a: "A (a x)"
   378     shows "P (a x)"
   379     using a
   380   proof (induct n == "a x" arbitrary: x)
   381     ...
   382 
   383 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   384 particular technique.
   385 
   386 (3) This is how to perform existential reasoning ('obtains' or
   387 'obtain') by induction, while avoiding explicit object-logic
   388 encodings:
   389 
   390   lemma
   391     fixes n :: nat
   392     obtains x :: 'a where "P n x" and "Q n x"
   393   proof (induct n arbitrary: thesis)
   394     case 0
   395     obtain x where "P 0 x" and "Q 0 x" sorry
   396     then show thesis by (rule 0)
   397   next
   398     case (Suc n)
   399     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   400     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   401     then show thesis by (rule Suc.prems)
   402   qed
   403 
   404 Here the 'arbitrary: thesis' specification essentially modifies the
   405 scope of the formal thesis parameter, in order to the get the whole
   406 existence statement through the induction as expected.
   407 
   408 * Provers/induct: mutual induction rules are now specified as a list
   409 of rule sharing the same induction cases.  HOL packages usually
   410 provide foo_bar.inducts for mutually defined items foo and bar
   411 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   412 specify mutual induction rules differently, i.e. like this:
   413 
   414   (induct rule: foo_bar.inducts)
   415   (induct set: foo bar)
   416   (induct type: foo bar)
   417 
   418 The ML function ProjectRule.projections turns old-style rules into the
   419 new format.
   420 
   421 * Provers/induct: improved handling of simultaneous goals.  Instead of
   422 introducing object-level conjunction, the statement is now split into
   423 several conclusions, while the corresponding symbolic cases are
   424 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   425 explicitly.  For example:
   426 
   427   lemma
   428     fixes n :: nat
   429     shows "P n" and "Q n"
   430   proof (induct n)
   431     case 0 case 1
   432     show "P 0" sorry
   433   next
   434     case 0 case 2
   435     show "Q 0" sorry
   436   next
   437     case (Suc n) case 1
   438     note `P n` and `Q n`
   439     show "P (Suc n)" sorry
   440   next
   441     case (Suc n) case 2
   442     note `P n` and `Q n`
   443     show "Q (Suc n)" sorry
   444   qed
   445 
   446 The split into subcases may be deferred as follows -- this is
   447 particularly relevant for goal statements with local premises.
   448 
   449   lemma
   450     fixes n :: nat
   451     shows "A n ==> P n" and "B n ==> Q n"
   452   proof (induct n)
   453     case 0
   454     {
   455       case 1
   456       note `A 0`
   457       show "P 0" sorry
   458     next
   459       case 2
   460       note `B 0`
   461       show "Q 0" sorry
   462     }
   463   next
   464     case (Suc n)
   465     note `A n ==> P n` and `B n ==> Q n`
   466     {
   467       case 1
   468       note `A (Suc n)`
   469       show "P (Suc n)" sorry
   470     next
   471       case 2
   472       note `B (Suc n)`
   473       show "Q (Suc n)" sorry
   474     }
   475   qed
   476 
   477 If simultaneous goals are to be used with mutual rules, the statement
   478 needs to be structured carefully as a two-level conjunction, using
   479 lists of propositions separated by 'and':
   480 
   481   lemma
   482     shows "a : A ==> P1 a"
   483           "a : A ==> P2 a"
   484       and "b : B ==> Q1 b"
   485           "b : B ==> Q2 b"
   486           "b : B ==> Q3 b"
   487   proof (induct set: A B)
   488 
   489 * Provers/induct: support coinduction as well.  See
   490 src/HOL/Library/Coinductive_List.thy for various examples.
   491 
   492 * Attribute "symmetric" produces result with standardized schematic
   493 variables (index 0).  Potential INCOMPATIBILITY.
   494 
   495 * Simplifier: by default the simplifier trace only shows top level
   496 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   497 default. Thus there is less danger of being flooded by the trace. The
   498 trace indicates where parts have been suppressed.
   499   
   500 * Provers/classical: removed obsolete classical version of elim_format
   501 attribute; classical elim/dest rules are now treated uniformly when
   502 manipulating the claset.
   503 
   504 * Provers/classical: stricter checks to ensure that supplied intro,
   505 dest and elim rules are well-formed; dest and elim rules must have at
   506 least one premise.
   507 
   508 * Provers/classical: attributes dest/elim/intro take an optional
   509 weight argument for the rule (just as the Pure versions).  Weights are
   510 ignored by automated tools, but determine the search order of single
   511 rule steps.
   512 
   513 * Syntax: input syntax now supports dummy variable binding "%_. b",
   514 where the body does not mention the bound variable.  Note that dummy
   515 patterns implicitly depend on their context of bounds, which makes
   516 "{_. _}" match any set comprehension as expected.  Potential
   517 INCOMPATIBILITY -- parse translations need to cope with syntactic
   518 constant "_idtdummy" in the binding position.
   519 
   520 * Syntax: removed obsolete syntactic constant "_K" and its associated
   521 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   522 for example "A -> B" => "Pi A (%_. B)".
   523 
   524 * Pure: 'class_deps' command visualizes the subclass relation, using
   525 the graph browser tool.
   526 
   527 * Pure: 'print_theory' now suppresses entities with internal name
   528 (trailing "_") by default; use '!' option for full details.
   529 
   530 
   531 *** HOL ***
   532 
   533 * constant "List.op @" now named "List.append".  Use ML antiquotations
   534 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   535 possible incompatibilities when working on ML level.
   536 
   537 * Constant renames due to introduction of canonical name prefixing for
   538   class package:
   539 
   540     HOL.abs ~> HOL.minus_class.abs
   541     HOL.divide ~> HOL.divide_class.divide
   542     Nat.power ~> Nat.power_class.power
   543     Nat.size ~> Nat.size_class.size
   544     Numeral.number_of ~> Numeral.number_class.number_of
   545 
   546 * case expressions and primrec: missing cases now mapped to "undefined"
   547 instead of "arbitrary"
   548 
   549 * new constant "undefined" with axiom "undefined x = undefined"
   550 
   551 * new class "default" with associated constant "default"
   552 
   553 * new function listsum :: 'a list => 'a for arbitrary monoids.
   554   Special syntax: "SUM x <- xs. f x" (and latex variants)
   555 
   556 * Library/List_Comprehension.thy provides Haskell-like input syntax for list
   557   comprehensions.
   558 
   559 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   560     when generating code.
   561 
   562 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   563     when generating code.
   564 
   565 * Library/Commutative_Ring.thy: switched from recdef to function package;
   566     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   567 
   568 * Some steps towards more uniform lattice theory development in HOL.
   569 
   570     constants "meet" and "join" now named "inf" and "sup"
   571     constant "Meet" now named "Inf"
   572 
   573     classes "meet_semilorder" and "join_semilorder" now named
   574       "lower_semilattice" and "upper_semilattice"
   575     class "lorder" now named "lattice"
   576     class "comp_lat" now named "complete_lattice"
   577 
   578     Instantiation of lattice classes allows explicit definitions
   579     for "inf" and "sup" operations.
   580 
   581   INCOMPATIBILITY. Theorem renames:
   582 
   583     meet_left_le            ~> inf_le1
   584     meet_right_le           ~> inf_le2
   585     join_left_le            ~> sup_ge1
   586     join_right_le           ~> sup_ge2
   587     meet_join_le            ~> inf_sup_ord
   588     le_meetI                ~> le_infI
   589     join_leI                ~> le_supI
   590     le_meet                 ~> le_inf_iff
   591     le_join                 ~> ge_sup_conv
   592     meet_idempotent         ~> inf_idem
   593     join_idempotent         ~> sup_idem
   594     meet_comm               ~> inf_commute
   595     join_comm               ~> sup_commute
   596     meet_leI1               ~> le_infI1
   597     meet_leI2               ~> le_infI2
   598     le_joinI1               ~> le_supI1
   599     le_joinI2               ~> le_supI2
   600     meet_assoc              ~> inf_assoc
   601     join_assoc              ~> sup_assoc
   602     meet_left_comm          ~> inf_left_commute
   603     meet_left_idempotent    ~> inf_left_idem
   604     join_left_comm          ~> sup_left_commute
   605     join_left_idempotent    ~> sup_left_idem
   606     meet_aci                ~> inf_aci
   607     join_aci                ~> sup_aci
   608     le_def_meet             ~> le_iff_inf
   609     le_def_join             ~> le_iff_sup
   610     join_absorp2            ~> sup_absorb2
   611     join_absorp1            ~> sup_absorb1
   612     meet_absorp1            ~> inf_absorb1
   613     meet_absorp2            ~> inf_absorb2
   614     meet_join_absorp        ~> inf_sup_absorb
   615     join_meet_absorp        ~> sup_inf_absorb
   616     distrib_join_le         ~> distrib_sup_le
   617     distrib_meet_le         ~> distrib_inf_le
   618 
   619     add_meet_distrib_left   ~> add_inf_distrib_left
   620     add_join_distrib_left   ~> add_sup_distrib_left
   621     is_join_neg_meet        ~> is_join_neg_inf
   622     is_meet_neg_join        ~> is_meet_neg_sup
   623     add_meet_distrib_right  ~> add_inf_distrib_right
   624     add_join_distrib_right  ~> add_sup_distrib_right
   625     add_meet_join_distribs  ~> add_sup_inf_distribs
   626     join_eq_neg_meet        ~> sup_eq_neg_inf
   627     meet_eq_neg_join        ~> inf_eq_neg_sup
   628     add_eq_meet_join        ~> add_eq_inf_sup
   629     meet_0_imp_0            ~> inf_0_imp_0
   630     join_0_imp_0            ~> sup_0_imp_0
   631     meet_0_eq_0             ~> inf_0_eq_0
   632     join_0_eq_0             ~> sup_0_eq_0
   633     neg_meet_eq_join        ~> neg_inf_eq_sup
   634     neg_join_eq_meet        ~> neg_sup_eq_inf
   635     join_eq_if              ~> sup_eq_if
   636 
   637     mono_meet               ~> mono_inf
   638     mono_join               ~> mono_sup
   639     meet_bool_eq            ~> inf_bool_eq
   640     join_bool_eq            ~> sup_bool_eq
   641     meet_fun_eq             ~> inf_fun_eq
   642     join_fun_eq             ~> sup_fun_eq
   643     meet_set_eq             ~> inf_set_eq
   644     join_set_eq             ~> sup_set_eq
   645     meet1_iff               ~> inf1_iff
   646     meet2_iff               ~> inf2_iff
   647     meet1I                  ~> inf1I
   648     meet2I                  ~> inf2I
   649     meet1D1                 ~> inf1D1
   650     meet2D1                 ~> inf2D1
   651     meet1D2                 ~> inf1D2
   652     meet2D2                 ~> inf2D2
   653     meet1E                  ~> inf1E
   654     meet2E                  ~> inf2E
   655     join1_iff               ~> sup1_iff
   656     join2_iff               ~> sup2_iff
   657     join1I1                 ~> sup1I1
   658     join2I1                 ~> sup2I1
   659     join1I1                 ~> sup1I1
   660     join2I2                 ~> sup1I2
   661     join1CI                 ~> sup1CI
   662     join2CI                 ~> sup2CI
   663     join1E                  ~> sup1E
   664     join2E                  ~> sup2E
   665 
   666     is_meet_Meet            ~> is_meet_Inf
   667     Meet_bool_def           ~> Inf_bool_def
   668     Meet_fun_def            ~> Inf_fun_def
   669     Meet_greatest           ~> Inf_greatest
   670     Meet_lower              ~> Inf_lower
   671     Meet_set_def            ~> Inf_set_def
   672 
   673     listsp_meetI            ~> listsp_infI
   674     listsp_meet_eq          ~> listsp_inf_eq
   675 
   676     meet_min                ~> inf_min
   677     join_max                ~> sup_max
   678 
   679 * Classes "order" and "linorder": facts "refl", "trans" and
   680 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   681 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   682 
   683 * Classes "order" and "linorder": 
   684 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   685 proofs changed.
   686 
   687 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   688 INCOMPATIBILITY.
   689 
   690 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   691 INCOMPATIBILITY.
   692 
   693 * Added syntactic class "size"; overloaded constant "size" now has
   694 type "'a::size ==> bool"
   695 
   696 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   697 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   698 
   699 * Added method "lexicographic_order" automatically synthesizes
   700 termination relations as lexicographic combinations of size measures
   701 -- 'function' package.
   702 
   703 * HOL/records: generalised field-update to take a function on the
   704 field rather than the new value: r(|A := x|) is translated to A_update
   705 (K x) r The K-combinator that is internally used is called K_record.
   706 INCOMPATIBILITY: Usage of the plain update functions has to be
   707 adapted.
   708  
   709 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   710 0 * x = 0, which are required for a semiring.  Richer structures do
   711 not inherit from semiring_0 anymore, because this property is a
   712 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   713 semiring_0, there is more to prove, but this is mostly trivial.
   714 
   715 * axclass "recpower" was generalized to arbitrary monoids, not just
   716 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   717 commutativity or a semiring property, add the corresponding classes.
   718 
   719 * Unified locale partial_order with class definition (cf. theory
   720 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   721 
   722 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   723 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   724 Isar level, use abbreviations instead.
   725 
   726 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   727 rarely occuring name references (e.g. ``List.op mem.simps'') require
   728 renaming (e.g. ``List.memberl.simps'').
   729 
   730 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   731 INCOMPATIBILITY.
   732 
   733 * Added theory Code_Generator providing class 'eq', allowing for code
   734 generation with polymorphic equality.
   735 
   736 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   737 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   738 significant changes for setting up numeral syntax for types:
   739 
   740   - new constants Numeral.pred and Numeral.succ instead
   741       of former Numeral.bin_pred and Numeral.bin_succ.
   742   - Use integer operations instead of bin_add, bin_mult and so on.
   743   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   744   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   745 
   746 See HOL/Integ/IntArith.thy for an example setup.
   747 
   748 * New top level command 'normal_form' computes the normal form of a
   749 term that may contain free variables. For example ``normal_form
   750 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   751 suitable for heavy-duty computations because the functions are
   752 compiled to ML first.
   753 
   754 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   755 25 like -->); output depends on the "iff" print_mode, the default is
   756 "A = B" (with priority 50).
   757 
   758 * Renamed constants in HOL.thy and Orderings.thy:
   759     op +   ~> HOL.plus_class.plus
   760     op -   ~> HOL.minus_class.minus
   761     uminus ~> HOL.minus_class.uminus
   762     op *   ~> HOL.times_class.times
   763     op <   ~> Orderings.ord_class.less
   764     op <=  ~> Orderings.ord_class.less_eq
   765 
   766 Adaptions may be required in the following cases:
   767 
   768 a) User-defined constants using any of the names "plus", "minus", "times",
   769 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   770 may go wrong.
   771 INCOMPATIBILITY: use more specific names.
   772 
   773 b) Variables named "plus", "minus", "times", "less", "less_eq"
   774 INCOMPATIBILITY: use more specific names.
   775 
   776 c) Permutative equations (e.g. "a + b = b + a")
   777 Since the change of names also changes the order of terms, permutative
   778 rewrite rules may get applied in a different order. Experience shows that
   779 this is rarely the case (only two adaptions in the whole Isabelle
   780 distribution).
   781 INCOMPATIBILITY: rewrite proofs
   782 
   783 d) ML code directly refering to constant names
   784 This in general only affects hand-written proof tactics, simprocs and so on.
   785 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   786 of const_name ML antiquotations.
   787 
   788 * Relations less (<) and less_eq (<=) are also available on type bool.
   789 Modified syntax to disallow nesting without explicit parentheses,
   790 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   791 
   792 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   793 
   794 * Relation composition operator "op O" now has precedence 75 and binds
   795 stronger than union and intersection. INCOMPATIBILITY.
   796 
   797 * The old set interval syntax "{m..n(}" (and relatives) has been
   798 removed.  Use "{m..<n}" (and relatives) instead.
   799 
   800 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   801 "t = s" to False (by simproc "neq_simproc").  For backward
   802 compatibility this can be disabled by ML "reset use_neq_simproc".
   803 
   804 * "m dvd n" where m and n are numbers is evaluated to True/False by
   805 simp.
   806 
   807 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   808 
   809 * Theorem setsum_mult renamed to setsum_right_distrib.
   810 
   811 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   812 ``rule'' method.
   813 
   814 * Reimplemented methods ``sat'' and ``satx'', with several
   815 improvements: goals no longer need to be stated as "<prems> ==>
   816 False", equivalences (i.e. "=" on type bool) are handled, variable
   817 names of the form "lit_<n>" are no longer reserved, significant
   818 speedup.
   819 
   820 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   821 zChaff is still supported as well.
   822 
   823 * 'inductive' and 'datatype': provide projections of mutual rules,
   824 bundled as foo_bar.inducts;
   825 
   826 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   827 Library.
   828 
   829 * Library: moved theory Accessible_Part to main HOL.
   830 
   831 * Library: added theory Coinductive_List of potentially infinite lists
   832 as greatest fixed-point.
   833 
   834 * Library: added theory AssocList which implements (finite) maps as
   835 association lists.
   836 
   837 * Added proof method ``evaluation'' for efficiently solving a goal
   838 (i.e. a boolean expression) by compiling it to ML. The goal is
   839 "proved" (via an oracle) if it evaluates to True.
   840 
   841 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   842 also when invoked by the simplifier.  This results in the simplifier
   843 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   844 fast_arith_split_limit to 0 to obtain the old behavior.
   845 
   846 * Support for hex (0x20) and binary (0b1001) numerals.
   847 
   848 * New method: reify eqs (t), where eqs are equations for an
   849 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   850 parameter, computes a term s::'b and a list xs::'a list and proves the
   851 theorem I xs s = t. This is also known as reification or quoting. The
   852 resulting theorem is applied to the subgoal to substitute t with I xs
   853 s.  If t is omitted, the subgoal itself is reified.
   854 
   855 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   856 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   857 where f is supposed to be a computable function (in the sense of code
   858 generattion). The method uses reify to compute s and xs as above then
   859 applies corr_thm and uses normalization by evaluation to "prove" f s =
   860 r and finally gets the theorem t = r, which is again applied to the
   861 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   862 
   863 * Reflection: Automatic refification now handels binding, an example
   864 is available in HOL/ex/ReflectionEx.thy
   865 
   866 
   867 *** HOL-Algebra ***
   868 
   869 * Formalisation of ideals and the quotient construction over rings.
   870 
   871 * Order and lattice theory no longer based on records.
   872 INCOMPATIBILITY.
   873 
   874 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   875 greatest_closed.  INCOMPATIBILITY.
   876 
   877 * Method algebra is now set up via an attribute.  For examples see
   878 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   879 of algebraic structures.
   880 
   881 * Renamed theory CRing to Ring.
   882 
   883 
   884 *** HOL-Complex ***
   885 
   886 * Theory Real: new method ferrack implements quantifier elimination
   887 for linear arithmetic over the reals. The quantifier elimination
   888 feature is used only for decision, for compatibility with arith. This
   889 means a goal is either solved or left unchanged, no simplification.
   890 
   891 * Hyperreal: Functions root and sqrt are now defined on negative real
   892 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
   893 Nonnegativity side conditions have been removed from many lemmas, so
   894 that more subgoals may now be solved by simplification; potential
   895 INCOMPATIBILITY.
   896 
   897 * Real: New axiomatic classes formalize real normed vector spaces and
   898 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   899 and norm :: 'a => real.
   900 
   901 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   902 from reals into other types. The overloaded constant Reals :: 'a set
   903 is now defined as range of_real; potential INCOMPATIBILITY.
   904 
   905 * Real: ML code generation is supported now and hence also quickcheck.
   906 Reals are implemented as arbitrary precision rationals.
   907 
   908 * Hyperreal: Several constants that previously worked only for the
   909 reals have been generalized, so they now work over arbitrary vector
   910 spaces. Type annotations may need to be added in some cases; potential
   911 INCOMPATIBILITY.
   912 
   913   Infinitesimal  :: ('a::real_normed_vector) star set
   914   HFinite        :: ('a::real_normed_vector) star set
   915   HInfinite      :: ('a::real_normed_vector) star set
   916   approx         :: ('a::real_normed_vector) star => 'a star => bool
   917   monad          :: ('a::real_normed_vector) star => 'a star set
   918   galaxy         :: ('a::real_normed_vector) star => 'a star set
   919   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
   920   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   921   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   922   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   923   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   924   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   925   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   926   sgn            :: 'a::real_normed_vector => 'a
   927 
   928 * Complex: Some complex-specific constants are now abbreviations for
   929 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   930 hnorm.  Other constants have been entirely removed in favor of the
   931 polymorphic versions (INCOMPATIBILITY):
   932 
   933   approx        <-- capprox
   934   HFinite       <-- CFinite
   935   HInfinite     <-- CInfinite
   936   Infinitesimal <-- CInfinitesimal
   937   monad         <-- cmonad
   938   galaxy        <-- cgalaxy
   939   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   940   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   941   (ns)deriv     <-- (ns)cderiv
   942 
   943 
   944 *** ML ***
   945 
   946 * Context data interfaces (Theory/Proof/GenericDataFun): removed
   947 name/print, uninitialized data defaults to ad-hoc copy of empty value,
   948 init only required for impure data.  INCOMPATIBILITY: empty really
   949 need to be empty (no dependencies on theory content!)
   950 
   951 * ML within Isar: antiquotations allow to embed statically-checked
   952 formal entities in the source, referring to the context available at
   953 compile-time.  For example:
   954 
   955 ML {* @{typ "'a => 'b"} *}
   956 ML {* @{term "%x. x"} *}
   957 ML {* @{prop "x == y"} *}
   958 ML {* @{ctyp "'a => 'b"} *}
   959 ML {* @{cterm "%x. x"} *}
   960 ML {* @{cprop "x == y"} *}
   961 ML {* @{thm asm_rl} *}
   962 ML {* @{thms asm_rl} *}
   963 ML {* @{const_name c} *}
   964 ML {* @{const_syntax c} *}
   965 ML {* @{context} *}
   966 ML {* @{theory} *}
   967 ML {* @{theory Pure} *}
   968 ML {* @{simpset} *}
   969 ML {* @{claset} *}
   970 ML {* @{clasimpset} *}
   971 
   972 The same works for sources being ``used'' within an Isar context.
   973 
   974 * ML in Isar: improved error reporting; extra verbosity with
   975 Toplevel.debug enabled.
   976 
   977 * Pure/library:
   978 
   979   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   980   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   981 
   982 The semantics of "burrow" is: "take a function with *simulatanously*
   983 transforms a list of value, and apply it *simulatanously* to a list of
   984 list of values of the appropriate type". Compare this with "map" which
   985 would *not* apply its argument function simulatanously but in
   986 sequence; "fold_burrow" has an additional context.
   987 
   988 * Pure/library: functions map2 and fold2 with curried syntax for
   989 simultanous mapping and folding:
   990 
   991     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   992     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   993 
   994 * Pure/library: indexed lists - some functions in the Isabelle library
   995 treating lists over 'a as finite mappings from [0...n] to 'a have been
   996 given more convenient names and signatures reminiscent of similar
   997 functions for alists, tables, etc:
   998 
   999   val nth: 'a list -> int -> 'a 
  1000   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1001   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1002 
  1003 Note that fold_index starts counting at index 0, not 1 like foldln
  1004 used to.
  1005 
  1006 * Pure/library: added general ``divide_and_conquer'' combinator on
  1007 lists.
  1008 
  1009 * Pure/General/table.ML: the join operations now works via exceptions
  1010 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1011 admits slightly more efficient complex applications.
  1012 
  1013 * Pure: datatype Context.generic joins theory/Proof.context and
  1014 provides some facilities for code that works in either kind of
  1015 context, notably GenericDataFun for uniform theory and proof data.
  1016 
  1017 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1018 use Context.generic instead of just theory.
  1019 
  1020 * Pure: simplified internal attribute type, which is now always
  1021 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1022 vs. local (Proof.context) attributes have been discontinued, while
  1023 minimizing code duplication.  Thm.rule_attribute and
  1024 Thm.declaration_attribute build canonical attributes; see also
  1025 structure Context for further operations on Context.generic, notably
  1026 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1027 declarations and definitions.
  1028 
  1029 * Pure/kernel: consts certification ignores sort constraints given in
  1030 signature declarations.  (This information is not relevant to the
  1031 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1032 potential INCOMPATIBILITY.
  1033 
  1034 * Pure: axiomatic type classes are now purely definitional, with
  1035 explicit proofs of class axioms and super class relations performed
  1036 internally.  See Pure/axclass.ML for the main internal interfaces --
  1037 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1038 AxClass.axiomatize_class/classrel/arity supercede
  1039 Sign.add_classes/classrel/arities.
  1040 
  1041 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1042 global/local versions on theory vs. Proof.context have been
  1043 discontinued; Attrib.syntax and Method.syntax have been adapted
  1044 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1045 attributes, methods, etc.
  1046 
  1047 * Pure: several functions of signature "... -> theory -> theory * ..."
  1048 have been reoriented to "... -> theory -> ... * theory" in order to
  1049 allow natural usage in combination with the ||>, ||>>, |-> and
  1050 fold_map combinators.
  1051 
  1052 * Pure: official theorem names (closed derivations) and additional
  1053 comments (tags) are now strictly separate.  Name hints -- which are
  1054 maintained as tags -- may be attached any time without affecting the
  1055 derivation.
  1056 
  1057 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1058 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1059 achieve the old behaviour.
  1060 
  1061 * Pure: the "Goal" constant is now called "prop", supporting a
  1062 slightly more general idea of ``protecting'' meta-level rule
  1063 statements.
  1064 
  1065 * Pure: Logic.(un)varify only works in a global context, which is now
  1066 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1067 Logic.legacy_(un)varify as temporary workaround.
  1068 
  1069 * Pure: structure Name provides scalable operations for generating
  1070 internal variable names, notably Name.variants etc.  This replaces
  1071 some popular functions from term.ML:
  1072 
  1073   Term.variant		->  Name.variant
  1074   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1075   Term.invent_names	->  Name.invent_list
  1076 
  1077 Note that low-level renaming rarely occurs in new code -- operations
  1078 from structure Variable are used instead (see below).
  1079 
  1080 * Pure: structure Variable provides fundamental operations for proper
  1081 treatment of fixed/schematic variables in a context.  For example,
  1082 Variable.import introduces fixes for schematics of given facts and
  1083 Variable.export reverses the effect (up to renaming) -- this replaces
  1084 various freeze_thaw operations.
  1085 
  1086 * Pure: structure Goal provides simple interfaces for
  1087 init/conclude/finish and tactical prove operations (replacing former
  1088 Tactic.prove).  Goal.prove is the canonical way to prove results
  1089 within a given context; Goal.prove_global is a degraded version for
  1090 theory level goals, including a global Drule.standard.  Note that
  1091 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1092 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1093 in a locale context).
  1094 
  1095 * Isar: simplified treatment of user-level errors, using exception
  1096 ERROR of string uniformly.  Function error now merely raises ERROR,
  1097 without any side effect on output channels.  The Isar toplevel takes
  1098 care of proper display of ERROR exceptions.  ML code may use plain
  1099 handle/can/try; cat_error may be used to concatenate errors like this:
  1100 
  1101   ... handle ERROR msg => cat_error msg "..."
  1102 
  1103 Toplevel ML code (run directly or through the Isar toplevel) may be
  1104 embedded into the Isar toplevel with exception display/debug like
  1105 this:
  1106 
  1107   Isar.toplevel (fn () => ...)
  1108 
  1109 INCOMPATIBILITY, removed special transform_error facilities, removed
  1110 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1111 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1112 -- use plain ERROR instead.
  1113 
  1114 * Isar: theory setup now has type (theory -> theory), instead of a
  1115 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1116 
  1117 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1118 subject to ProofContext.debug/verbose flags.
  1119 
  1120 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1121 theory before entering a proof state.  Transactions now always see a
  1122 quasi-functional intermediate checkpoint, both in interactive and
  1123 batch mode.
  1124 
  1125 * Simplifier: the simpset of a running simplification process now
  1126 contains a proof context (cf. Simplifier.the_context), which is the
  1127 very context that the initial simpset has been retrieved from (by
  1128 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1129 (solver, looper etc.) may depend on arbitrary proof data.
  1130 
  1131 * Simplifier.inherit_context inherits the proof context (plus the
  1132 local bounds) of the current simplification process; any simproc
  1133 etc. that calls the Simplifier recursively should do this!  Removed
  1134 former Simplifier.inherit_bounds, which is already included here --
  1135 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1136 specify an explicit context using Simplifier.context/theory_context.
  1137 
  1138 * Simplifier/Classical Reasoner: more abstract interfaces
  1139 change_simpset/claset for modifying the simpset/claset reference of a
  1140 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1141 INCOMPATIBILITY.
  1142 
  1143 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1144 "Trueprop" etc.
  1145 
  1146 
  1147 *** System ***
  1148 
  1149 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1150 locations -- now includes the Isabelle version identifier as well.
  1151 This simplifies use of multiple Isabelle installations.
  1152 
  1153 * isabelle-process: option -S (secure mode) disables some critical
  1154 operations, notably runtime compilation and evaluation of ML source
  1155 code.
  1156 
  1157 
  1158 New in Isabelle2005 (October 2005)
  1159 ----------------------------------
  1160 
  1161 *** General ***
  1162 
  1163 * Theory headers: the new header syntax for Isar theories is
  1164 
  1165   theory <name>
  1166   imports <theory1> ... <theoryN>
  1167   uses <file1> ... <fileM>
  1168   begin
  1169 
  1170 where the 'uses' part is optional.  The previous syntax
  1171 
  1172   theory <name> = <theory1> + ... + <theoryN>:
  1173 
  1174 will disappear in the next release.  Use isatool fixheaders to convert
  1175 existing theory files.  Note that there is no change in ancient
  1176 non-Isar theories now, but these will disappear soon.
  1177 
  1178 * Theory loader: parent theories can now also be referred to via
  1179 relative and absolute paths.
  1180 
  1181 * Command 'find_theorems' searches for a list of criteria instead of a
  1182 list of constants. Known criteria are: intro, elim, dest, name:string,
  1183 simp:term, and any term. Criteria can be preceded by '-' to select
  1184 theorems that do not match. Intro, elim, dest select theorems that
  1185 match the current goal, name:s selects theorems whose fully qualified
  1186 name contain s, and simp:term selects all simplification rules whose
  1187 lhs match term.  Any other term is interpreted as pattern and selects
  1188 all theorems matching the pattern. Available in ProofGeneral under
  1189 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1190 
  1191   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1192 
  1193 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1194 matching the current goal as introduction rule and not having "HOL."
  1195 in their name (i.e. not being defined in theory HOL).
  1196 
  1197 * Command 'thms_containing' has been discontinued in favour of
  1198 'find_theorems'; INCOMPATIBILITY.
  1199 
  1200 * Communication with Proof General is now 8bit clean, which means that
  1201 Unicode text in UTF-8 encoding may be used within theory texts (both
  1202 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1203 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1204 
  1205   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1206   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1207 
  1208 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1209 Classical Reasoner.  Typical big applications run around 2 times
  1210 faster.
  1211 
  1212 
  1213 *** Document preparation ***
  1214 
  1215 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1216 of raw sources.  Only those symbols that do not require additional
  1217 LaTeX packages (depending on comments in isabellesym.sty) are
  1218 displayed properly, everything else is left verbatim.  isatool display
  1219 and isatool print are used as front ends (these are subject to the
  1220 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1221 
  1222 * Command tags control specific markup of certain regions of text,
  1223 notably folding and hiding.  Predefined tags include "theory" (for
  1224 theory begin and end), "proof" for proof commands, and "ML" for
  1225 commands involving ML code; the additional tags "visible" and
  1226 "invisible" are unused by default.  Users may give explicit tag
  1227 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1228 interpretation of tags is determined by the LaTeX job during document
  1229 preparation: see option -V of isatool usedir, or options -n and -t of
  1230 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1231 \isadroptag.
  1232 
  1233 Several document versions may be produced at the same time via isatool
  1234 usedir (the generated index.html will link all of them).  Typical
  1235 specifications include ''-V document=theory,proof,ML'' to present
  1236 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1237 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1238 these parts without any formal replacement text.  The Isabelle site
  1239 default settings produce ''document'' and ''outline'' versions as
  1240 specified above.
  1241 
  1242 * Several new antiquotations:
  1243 
  1244   @{term_type term} prints a term with its type annotated;
  1245 
  1246   @{typeof term} prints the type of a term;
  1247 
  1248   @{const const} is the same as @{term const}, but checks that the
  1249   argument is a known logical constant;
  1250 
  1251   @{term_style style term} and @{thm_style style thm} print a term or
  1252   theorem applying a "style" to it
  1253 
  1254   @{ML text}
  1255 
  1256 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1257 definitions, equations, inequations etc., 'concl' printing only the
  1258 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1259 to print the specified premise.  TermStyle.add_style provides an ML
  1260 interface for introducing further styles.  See also the "LaTeX Sugar"
  1261 document practical applications.  The ML antiquotation prints
  1262 type-checked ML expressions verbatim.
  1263 
  1264 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1265 and 'text' support optional locale specification '(in loc)', which
  1266 specifies the default context for interpreting antiquotations.  For
  1267 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1268 
  1269 * Option 'locale=NAME' of antiquotations specifies an alternative
  1270 context interpreting the subsequent argument.  For example: @{thm
  1271 [locale=lattice] inf_assoc}.
  1272 
  1273 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1274 a proof context.
  1275 
  1276 * Proper output of antiquotations for theory commands involving a
  1277 proof context (such as 'locale' or 'theorem (in loc) ...').
  1278 
  1279 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1280 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1281 
  1282 * isatool usedir: new option -C (default true) controls whether option
  1283 -D should include a copy of the original document directory; -C false
  1284 prevents unwanted effects such as copying of administrative CVS data.
  1285 
  1286 
  1287 *** Pure ***
  1288 
  1289 * Considerably improved version of 'constdefs' command.  Now performs
  1290 automatic type-inference of declared constants; additional support for
  1291 local structure declarations (cf. locales and HOL records), see also
  1292 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1293 sequential dependencies of definitions within a single 'constdefs'
  1294 section; moreover, the declared name needs to be an identifier.  If
  1295 all fails, consider to fall back on 'consts' and 'defs' separately.
  1296 
  1297 * Improved indexed syntax and implicit structures.  First of all,
  1298 indexed syntax provides a notational device for subscripted
  1299 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1300 expressions.  Secondly, in a local context with structure
  1301 declarations, number indexes \<^sub>n or the empty index (default
  1302 number 1) refer to a certain fixed variable implicitly; option
  1303 show_structs controls printing of implicit structures.  Typical
  1304 applications of these concepts involve record types and locales.
  1305 
  1306 * New command 'no_syntax' removes grammar declarations (and
  1307 translations) resulting from the given syntax specification, which is
  1308 interpreted in the same manner as for the 'syntax' command.
  1309 
  1310 * 'Advanced' translation functions (parse_translation etc.) may depend
  1311 on the signature of the theory context being presently used for
  1312 parsing/printing, see also isar-ref manual.
  1313 
  1314 * Improved 'oracle' command provides a type-safe interface to turn an
  1315 ML expression of type theory -> T -> term into a primitive rule of
  1316 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1317 is already included here); see also FOL/ex/IffExample.thy;
  1318 INCOMPATIBILITY.
  1319 
  1320 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1321 before); "cI" is no longer bound, use "c.intro" instead.
  1322 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1323 axclasses vs. locales.
  1324 
  1325 * Improved internal renaming of symbolic identifiers -- attach primes
  1326 instead of base 26 numbers.
  1327 
  1328 * New flag show_question_marks controls printing of leading question
  1329 marks in schematic variable names.
  1330 
  1331 * In schematic variable names, *any* symbol following \<^isub> or
  1332 \<^isup> is now treated as part of the base name.  For example, the
  1333 following works without printing of awkward ".0" indexes:
  1334 
  1335   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1336     by simp
  1337 
  1338 * Inner syntax includes (*(*nested*) comments*).
  1339 
  1340 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1341 annotations as "(00...)".
  1342 
  1343 * Clear separation of logical types and nonterminals, where the latter
  1344 may only occur in 'syntax' specifications or type abbreviations.
  1345 Before that distinction was only partially implemented via type class
  1346 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1347 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1348 exotic syntax specifications may require further adaption
  1349 (e.g. Cube/Cube.thy).
  1350 
  1351 * Removed obsolete type class "logic", use the top sort {} instead.
  1352 Note that non-logical types should be declared as 'nonterminals'
  1353 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1354 specifications.
  1355 
  1356 * Attributes 'induct' and 'cases': type or set names may now be
  1357 locally fixed variables as well.
  1358 
  1359 * Simplifier: can now control the depth to which conditional rewriting
  1360 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1361 Limit.
  1362 
  1363 * Simplifier: simplification procedures may now take the current
  1364 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1365 interface), which is very useful for calling the Simplifier
  1366 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1367 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1368 low-level mk_simproc no longer applies Logic.varify internally, to
  1369 allow for use in a context of fixed variables.
  1370 
  1371 * thin_tac now works even if the assumption being deleted contains !!
  1372 or ==>.  More generally, erule now works even if the major premise of
  1373 the elimination rule contains !! or ==>.
  1374 
  1375 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1376 
  1377 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1378 from Pure, which contains all common declarations already.  Both
  1379 theories are defined via plain Isabelle/Isar .thy files.
  1380 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1381 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1382 use isatool fixcpure to adapt your theory and ML sources.
  1383 
  1384 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1385 selections of theorems in named facts via index ranges.
  1386 
  1387 * 'print_theorems': in theory mode, really print the difference
  1388 wrt. the last state (works for interactive theory development only),
  1389 in proof mode print all local facts (cf. 'print_facts');
  1390 
  1391 * 'hide': option '(open)' hides only base names.
  1392 
  1393 * More efficient treatment of intermediate checkpoints in interactive
  1394 theory development.
  1395 
  1396 * Code generator is now invoked via code_module (incremental code
  1397 generation) and code_library (modular code generation, ML structures
  1398 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1399 must be quoted when used as identifiers.
  1400 
  1401 * New 'value' command for reading, evaluating and printing terms using
  1402 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1403 quoted when used as identifier.
  1404 
  1405 
  1406 *** Locales ***
  1407 
  1408 * New commands for the interpretation of locale expressions in
  1409 theories (1), locales (2) and proof contexts (3).  These generate
  1410 proof obligations from the expression specification.  After the
  1411 obligations have been discharged, theorems of the expression are added
  1412 to the theory, target locale or proof context.  The synopsis of the
  1413 commands is a follows:
  1414 
  1415   (1) interpretation expr inst
  1416   (2) interpretation target < expr
  1417   (3) interpret expr inst
  1418 
  1419 Interpretation in theories and proof contexts require a parameter
  1420 instantiation of terms from the current context.  This is applied to
  1421 specifications and theorems of the interpreted expression.
  1422 Interpretation in locales only permits parameter renaming through the
  1423 locale expression.  Interpretation is smart in that interpretations
  1424 that are active already do not occur in proof obligations, neither are
  1425 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1426 inspect active interpretations of a particular locale.  For details,
  1427 see the Isar Reference manual.  Examples can be found in
  1428 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1429 
  1430 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1431 'interpret' instead.
  1432 
  1433 * New context element 'constrains' for adding type constraints to
  1434 parameters.
  1435 
  1436 * Context expressions: renaming of parameters with syntax
  1437 redeclaration.
  1438 
  1439 * Locale declaration: 'includes' disallowed.
  1440 
  1441 * Proper static binding of attribute syntax -- i.e. types / terms /
  1442 facts mentioned as arguments are always those of the locale definition
  1443 context, independently of the context of later invocations.  Moreover,
  1444 locale operations (renaming and type / term instantiation) are applied
  1445 to attribute arguments as expected.
  1446 
  1447 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1448 actual attributes; rare situations may require Attrib.attribute to
  1449 embed those attributes into Attrib.src that lack concrete syntax.
  1450 Attribute implementations need to cooperate properly with the static
  1451 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1452 Attrib.XXX_thm etc. already do the right thing without further
  1453 intervention.  Only unusual applications -- such as "where" or "of"
  1454 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1455 on the context and the facts involved -- may have to assign parsed
  1456 values to argument tokens explicitly.
  1457 
  1458 * Changed parameter management in theorem generation for long goal
  1459 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1460 theorem statement in rare situations.
  1461 
  1462 * Locale inspection command 'print_locale' omits notes elements.  Use
  1463 'print_locale!' to have them included in the output.
  1464 
  1465 
  1466 *** Provers ***
  1467 
  1468 * Provers/hypsubst.ML: improved version of the subst method, for
  1469 single-step rewriting: it now works in bound variable contexts. New is
  1470 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1471 rewrite a different subterm than the original subst method, which is
  1472 still available as 'simplesubst'.
  1473 
  1474 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1475 and quasi orders.
  1476 
  1477 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1478 reflexive-transitive closure of relations.
  1479 
  1480 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1481 limit (previously hard-coded with a value of 20) user-definable.
  1482 
  1483 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1484 is peformed already.  Object-logics merely need to finish their
  1485 initial simpset configuration as before.  INCOMPATIBILITY.
  1486 
  1487 
  1488 *** HOL ***
  1489 
  1490 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1491 
  1492   syntax (epsilon)
  1493     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1494 
  1495 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1496 and x-symbol; use option '-m epsilon' to get it actually printed.
  1497 Moreover, the mathematically important symbolic identifier \<epsilon>
  1498 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1499 
  1500 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1501 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1502 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1503 support corresponding Isar calculations.
  1504 
  1505 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1506 instead of ":".
  1507 
  1508 * theory SetInterval: changed the syntax for open intervals:
  1509 
  1510   Old       New
  1511   {..n(}    {..<n}
  1512   {)n..}    {n<..}
  1513   {m..n(}   {m..<n}
  1514   {)m..n}   {m<..n}
  1515   {)m..n(}  {m<..<n}
  1516 
  1517 The old syntax is still supported but will disappear in the next
  1518 release.  For conversion use the following Emacs search and replace
  1519 patterns (these are not perfect but work quite well):
  1520 
  1521   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1522   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1523 
  1524 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1525 equalities in commutative rings; method 'algebra' provides a generic
  1526 interface.
  1527 
  1528 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1529 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1530 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1531 be a tuple pattern.
  1532 
  1533 Some new syntax forms are available:
  1534 
  1535   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1536   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1537   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1538   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1539 
  1540 The latter form "\<Sum>x < k. e" used to be based on a separate
  1541 function "Summation", which has been discontinued.
  1542 
  1543 * theory Finite_Set: in structured induction proofs, the insert case
  1544 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1545 (insert F x)'.
  1546 
  1547 * The 'refute' command has been extended to support a much larger
  1548 fragment of HOL, including axiomatic type classes, constdefs and
  1549 typedefs, inductive datatypes and recursion.
  1550 
  1551 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1552 Requires zChaff with proof generation to be installed.  See
  1553 HOL/ex/SAT_Examples.thy for examples.
  1554 
  1555 * Datatype induction via method 'induct' now preserves the name of the
  1556 induction variable. For example, when proving P(xs::'a list) by
  1557 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1558 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1559 in unstructured proof scripts.
  1560 
  1561 * Reworked implementation of records.  Improved scalability for
  1562 records with many fields, avoiding performance problems for type
  1563 inference. Records are no longer composed of nested field types, but
  1564 of nested extension types. Therefore the record type only grows linear
  1565 in the number of extensions and not in the number of fields.  The
  1566 top-level (users) view on records is preserved.  Potential
  1567 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1568 old record representation. The type generated for a record is called
  1569 <record_name>_ext_type.
  1570 
  1571 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1572 proofs triggered by a record definition or a simproc (if
  1573 quick_and_dirty is enabled).  Definitions of large records can take
  1574 quite long.
  1575 
  1576 New simproc record_upd_simproc for simplification of multiple record
  1577 updates enabled by default.  Moreover, trivial updates are also
  1578 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1579 occasionally, since simplification is more powerful by default.
  1580 
  1581 * typedef: proper support for polymorphic sets, which contain extra
  1582 type-variables in the term.
  1583 
  1584 * Simplifier: automatically reasons about transitivity chains
  1585 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1586 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1587 old proofs break occasionally as simplification may now solve more
  1588 goals than previously.
  1589 
  1590 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1591 present.  Works for all partial orders (class "order"), in particular
  1592 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1593 just like y <= x.
  1594 
  1595 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1596 bound variable or a constant then the let is unfolded.  Otherwise
  1597 first a is simplified to b, and then f b is simplified to g. If
  1598 possible we abstract b from g arriving at "let x = b in h x",
  1599 otherwise we unfold the let and arrive at g.  The simproc can be
  1600 enabled/disabled by the reference use_let_simproc.  Potential
  1601 INCOMPATIBILITY since simplification is more powerful by default.
  1602 
  1603 * Classical reasoning: the meson method now accepts theorems as arguments.
  1604 
  1605 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1606 jobs to provide advice on the provability of subgoals.
  1607 
  1608 * Theory OrderedGroup and Ring_and_Field: various additions and
  1609 improvements to faciliate calculations involving equalities and
  1610 inequalities.
  1611 
  1612 The following theorems have been eliminated or modified
  1613 (INCOMPATIBILITY):
  1614 
  1615   abs_eq             now named abs_of_nonneg
  1616   abs_of_ge_0        now named abs_of_nonneg
  1617   abs_minus_eq       now named abs_of_nonpos
  1618   imp_abs_id         now named abs_of_nonneg
  1619   imp_abs_neg_id     now named abs_of_nonpos
  1620   mult_pos           now named mult_pos_pos
  1621   mult_pos_le        now named mult_nonneg_nonneg
  1622   mult_pos_neg_le    now named mult_nonneg_nonpos
  1623   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1624   mult_neg           now named mult_neg_neg
  1625   mult_neg_le        now named mult_nonpos_nonpos
  1626 
  1627 * Theory Parity: added rules for simplifying exponents.
  1628 
  1629 * Theory List:
  1630 
  1631 The following theorems have been eliminated or modified
  1632 (INCOMPATIBILITY):
  1633 
  1634   list_all_Nil       now named list_all.simps(1)
  1635   list_all_Cons      now named list_all.simps(2)
  1636   list_all_conv      now named list_all_iff
  1637   set_mem_eq         now named mem_iff
  1638 
  1639 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1640 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1641 
  1642 
  1643 *** HOL-Complex ***
  1644 
  1645 * Theory RealDef: better support for embedding natural numbers and
  1646 integers in the reals.
  1647 
  1648 The following theorems have been eliminated or modified
  1649 (INCOMPATIBILITY):
  1650 
  1651   exp_ge_add_one_self  now requires no hypotheses
  1652   real_of_int_add      reversed direction of equality (use [symmetric])
  1653   real_of_int_minus    reversed direction of equality (use [symmetric])
  1654   real_of_int_diff     reversed direction of equality (use [symmetric])
  1655   real_of_int_mult     reversed direction of equality (use [symmetric])
  1656 
  1657 * Theory RComplete: expanded support for floor and ceiling functions.
  1658 
  1659 * Theory Ln is new, with properties of the natural logarithm
  1660 
  1661 * Hyperreal: There is a new type constructor "star" for making
  1662 nonstandard types.  The old type names are now type synonyms:
  1663 
  1664   hypreal = real star
  1665   hypnat = nat star
  1666   hcomplex = complex star
  1667 
  1668 * Hyperreal: Many groups of similarly-defined constants have been
  1669 replaced by polymorphic versions (INCOMPATIBILITY):
  1670 
  1671   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1672 
  1673   starset      <-- starsetNat, starsetC
  1674   *s*          <-- *sNat*, *sc*
  1675   starset_n    <-- starsetNat_n, starsetC_n
  1676   *sn*         <-- *sNatn*, *scn*
  1677   InternalSets <-- InternalNatSets, InternalCSets
  1678 
  1679   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1680   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1681   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1682   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1683   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1684 
  1685 * Hyperreal: Many type-specific theorems have been removed in favor of
  1686 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1687 
  1688   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1689   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1690   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1691   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1692   right_minus <-- hypreal_add_minus
  1693   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1694   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1695   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1696   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1697   mult_1_right <-- hcomplex_mult_one_right
  1698   mult_zero_left <-- hcomplex_mult_zero_left
  1699   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1700   right_distrib <-- hypnat_add_mult_distrib2
  1701   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1702   right_inverse <-- hypreal_mult_inverse
  1703   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1704   order_refl <-- {hypreal,hypnat}_le_refl
  1705   order_trans <-- {hypreal,hypnat}_le_trans
  1706   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1707   order_less_le <-- {hypreal,hypnat}_less_le
  1708   linorder_linear <-- {hypreal,hypnat}_le_linear
  1709   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1710   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1711   add_nonneg_nonneg <-- hypreal_le_add_order
  1712 
  1713 * Hyperreal: Separate theorems having to do with type-specific
  1714 versions of constants have been merged into theorems that apply to the
  1715 new polymorphic constants (INCOMPATIBILITY):
  1716 
  1717   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1718   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1719   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1720   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1721   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1722   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1723   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1724   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1725   STAR_diff <-- {STAR,STARC}_diff
  1726   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1727     STARC_hcomplex_of_complex}_image_subset
  1728   starset_n_Un <-- starset{Nat,C}_n_Un
  1729   starset_n_Int <-- starset{Nat,C}_n_Int
  1730   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1731   starset_n_diff <-- starset{Nat,C}_n_diff
  1732   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1733   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1734   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1735   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1736   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1737   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1738   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1739   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1740   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1741   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1742   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1743   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1744   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1745   starfun_diff <-- starfun{C,RC,CR}_diff
  1746   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1747   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1748   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1749   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1750   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1751   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1752   starfun_Id <-- starfunC_Id
  1753   starfun_approx <-- starfun{Nat,CR}_approx
  1754   starfun_capprox <-- starfun{C,RC}_capprox
  1755   starfun_abs <-- starfunNat_rabs
  1756   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1757   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1758   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1759   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1760   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1761   starfun_add_approx <-- starfunCR_add_approx
  1762   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1763   starfun_divide <-- starfun{C,CR,RC}_divide
  1764   starfun_n <-- starfun{Nat,C}_n
  1765   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1766   starfun_n_add <-- starfun{Nat,C}_n_add
  1767   starfun_n_add_minus <-- starfunNat_n_add_minus
  1768   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1769   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1770   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1771 
  1772   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1773   star_n_minus <-- {hypreal,hcomplex}_minus
  1774   star_n_diff <-- {hypreal,hcomplex}_diff
  1775   star_n_mult <-- {hypreal,hcomplex}_mult
  1776   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1777   star_n_le <-- {hypreal,hypnat}_le
  1778   star_n_less <-- {hypreal,hypnat}_less
  1779   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1780   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1781   star_n_abs <-- hypreal_hrabs
  1782   star_n_divide <-- hcomplex_divide
  1783 
  1784   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1785   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1786   star_of_diff <-- hypreal_of_real_diff
  1787   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1788   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1789   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1790   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1791   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1792   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1793   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1794   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1795   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1796   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1797   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1798   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1799   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1800   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1801   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1802   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1803   star_of_power <-- hypreal_of_real_power
  1804   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1805 
  1806 * Hyperreal: new method "transfer" that implements the transfer
  1807 principle of nonstandard analysis. With a subgoal that mentions
  1808 nonstandard types like "'a star", the command "apply transfer"
  1809 replaces it with an equivalent one that mentions only standard types.
  1810 To be successful, all free variables must have standard types; non-
  1811 standard variables must have explicit universal quantifiers.
  1812 
  1813 * Hyperreal: A theory of Taylor series.
  1814 
  1815 
  1816 *** HOLCF ***
  1817 
  1818 * Discontinued special version of 'constdefs' (which used to support
  1819 continuous functions) in favor of the general Pure one with full
  1820 type-inference.
  1821 
  1822 * New simplification procedure for solving continuity conditions; it
  1823 is much faster on terms with many nested lambda abstractions (cubic
  1824 instead of exponential time).
  1825 
  1826 * New syntax for domain package: selector names are now optional.
  1827 Parentheses should be omitted unless argument is lazy, for example:
  1828 
  1829   domain 'a stream = cons "'a" (lazy "'a stream")
  1830 
  1831 * New command 'fixrec' for defining recursive functions with pattern
  1832 matching; defining multiple functions with mutual recursion is also
  1833 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1834 sinr, or any data constructor defined by the domain package. The given
  1835 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1836 syntax and examples.
  1837 
  1838 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1839 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1840 but the proof obligation additionally includes an admissibility
  1841 requirement. The packages generate instances of class cpo or pcpo,
  1842 with continuity and strictness theorems for Rep and Abs.
  1843 
  1844 * HOLCF: Many theorems have been renamed according to a more standard naming
  1845 scheme (INCOMPATIBILITY):
  1846 
  1847   foo_inject:  "foo$x = foo$y ==> x = y"
  1848   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1849   foo_less:    "(foo$x << foo$y) = (x << y)"
  1850   foo_strict:  "foo$UU = UU"
  1851   foo_defined: "... ==> foo$x ~= UU"
  1852   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1853 
  1854 
  1855 *** ZF ***
  1856 
  1857 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1858 including the First Isomorphism Theorem (on quotienting by the kernel
  1859 of a homomorphism).
  1860 
  1861 * ZF/Simplifier: install second copy of type solver that actually
  1862 makes use of TC rules declared to Isar proof contexts (or locales);
  1863 the old version is still required for ML proof scripts.
  1864 
  1865 
  1866 *** Cube ***
  1867 
  1868 * Converted to Isar theory format; use locales instead of axiomatic
  1869 theories.
  1870 
  1871 
  1872 *** ML ***
  1873 
  1874 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1875 for ||>, ||>>, |>>,
  1876 
  1877 * Pure/library.ML no longer defines its own option datatype, but uses
  1878 that of the SML basis, which has constructors NONE and SOME instead of
  1879 None and Some, as well as exception Option.Option instead of OPTION.
  1880 The functions the, if_none, is_some, is_none have been adapted
  1881 accordingly, while Option.map replaces apsome.
  1882 
  1883 * Pure/library.ML: the exception LIST has been given up in favour of
  1884 the standard exceptions Empty and Subscript, as well as
  1885 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1886 superceded by the standard hd and tl functions etc.
  1887 
  1888 A number of basic list functions are no longer exported to the ML
  1889 toplevel, as they are variants of predefined functions.  The following
  1890 suggests how one can translate existing code:
  1891 
  1892     rev_append xs ys = List.revAppend (xs, ys)
  1893     nth_elem (i, xs) = List.nth (xs, i)
  1894     last_elem xs = List.last xs
  1895     flat xss = List.concat xss
  1896     seq fs = List.app fs
  1897     partition P xs = List.partition P xs
  1898     mapfilter f xs = List.mapPartial f xs
  1899 
  1900 * Pure/library.ML: several combinators for linear functional
  1901 transformations, notably reverse application and composition:
  1902 
  1903   x |> f                f #> g
  1904   (x, y) |-> f          f #-> g
  1905 
  1906 * Pure/library.ML: introduced/changed precedence of infix operators:
  1907 
  1908   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1909   infix 2 ?;
  1910   infix 3 o oo ooo oooo;
  1911   infix 4 ~~ upto downto;
  1912 
  1913 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1914 infix operators.
  1915 
  1916 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1917 fold_map support linear functional transformations and nesting.  For
  1918 example:
  1919 
  1920   fold f [x1, ..., xN] y =
  1921     y |> f x1 |> ... |> f xN
  1922 
  1923   (fold o fold) f [xs1, ..., xsN] y =
  1924     y |> fold f xs1 |> ... |> fold f xsN
  1925 
  1926   fold f [x1, ..., xN] =
  1927     f x1 #> ... #> f xN
  1928 
  1929   (fold o fold) f [xs1, ..., xsN] =
  1930     fold f xs1 #> ... #> fold f xsN
  1931 
  1932 * Pure/library.ML: the following selectors on type 'a option are
  1933 available:
  1934 
  1935   the:               'a option -> 'a  (*partial*)
  1936   these:             'a option -> 'a  where 'a = 'b list
  1937   the_default: 'a -> 'a option -> 'a
  1938   the_list:          'a option -> 'a list
  1939 
  1940 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1941 basic operations for association lists, following natural argument
  1942 order; moreover the explicit equality predicate passed here avoids
  1943 potentially expensive polymorphic runtime equality checks.
  1944 The old functions may be expressed as follows:
  1945 
  1946   assoc = uncurry (AList.lookup (op =))
  1947   assocs = these oo AList.lookup (op =)
  1948   overwrite = uncurry (AList.update (op =)) o swap
  1949 
  1950 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1951 
  1952   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1953   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1954 
  1955 replacing make_keylist and keyfilter (occassionally used)
  1956 Naive rewrites:
  1957 
  1958   make_keylist = AList.make
  1959   keyfilter = AList.find (op =)
  1960 
  1961 * eq_fst and eq_snd now take explicit equality parameter, thus
  1962   avoiding eqtypes. Naive rewrites:
  1963 
  1964     eq_fst = eq_fst (op =)
  1965     eq_snd = eq_snd (op =)
  1966 
  1967 * Removed deprecated apl and apr (rarely used).
  1968   Naive rewrites:
  1969 
  1970     apl (n, op) =>>= curry op n
  1971     apr (op, m) =>>= fn n => op (n, m)
  1972 
  1973 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1974 provides a reasonably efficient light-weight implementation of sets as
  1975 lists.
  1976 
  1977 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1978 few new operations; existing lookup and update are now curried to
  1979 follow natural argument order (for use with fold etc.);
  1980 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1981 
  1982 * Pure/General: output via the Isabelle channels of
  1983 writeln/warning/error etc. is now passed through Output.output, with a
  1984 hook for arbitrary transformations depending on the print_mode
  1985 (cf. Output.add_mode -- the first active mode that provides a output
  1986 function wins).  Already formatted output may be embedded into further
  1987 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1988 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1989 accommodate easy composition of diagnostic messages etc.  Programmers
  1990 rarely need to care about Output.output or Output.raw at all, with
  1991 some notable exceptions: Output.output is required when bypassing the
  1992 standard channels (writeln etc.), or in token translations to produce
  1993 properly formatted results; Output.raw is required when capturing
  1994 already output material that will eventually be presented to the user
  1995 a second time.  For the default print mode, both Output.output and
  1996 Output.raw have no effect.
  1997 
  1998 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1999 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2000 cumulative results are displayed at the end of a batch session.
  2001 
  2002 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2003 replaced by File.platform_path and File.shell_path (with appropriate
  2004 hooks).  This provides a clean interface for unusual systems where the
  2005 internal and external process view of file names are different.
  2006 
  2007 * Pure: more efficient orders for basic syntactic entities: added
  2008 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2009 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2010 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2011 orders now -- potential INCOMPATIBILITY for code that depends on a
  2012 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2013 Library.sort_strings on result).
  2014 
  2015 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2016 fold_types traverse types/terms from left to right, observing natural
  2017 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2018 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2019 
  2020 * Pure: name spaces have been refined, with significant changes of the
  2021 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2022 to extern(_table).  The plain name entry path is superceded by a
  2023 general 'naming' context, which also includes the 'policy' to produce
  2024 a fully qualified name and external accesses of a fully qualified
  2025 name; NameSpace.extend is superceded by context dependent
  2026 Sign.declare_name.  Several theory and proof context operations modify
  2027 the naming context.  Especially note Theory.restore_naming and
  2028 ProofContext.restore_naming to get back to a sane state; note that
  2029 Theory.add_path is no longer sufficient to recover from
  2030 Theory.absolute_path in particular.
  2031 
  2032 * Pure: new flags short_names (default false) and unique_names
  2033 (default true) for controlling output of qualified names.  If
  2034 short_names is set, names are printed unqualified.  If unique_names is
  2035 reset, the name prefix is reduced to the minimum required to achieve
  2036 the original result when interning again, even if there is an overlap
  2037 with earlier declarations.
  2038 
  2039 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2040 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2041 (useful for printing error messages).  INCOMPATIBILITY.
  2042 
  2043 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2044 Theory.theory are now identified, referring to the universal
  2045 Context.theory (see Pure/context.ML).  Actual signature and theory
  2046 content is managed as theory data.  The old code and interfaces were
  2047 spread over many files and structures; the new arrangement introduces
  2048 considerable INCOMPATIBILITY to gain more clarity:
  2049 
  2050   Context -- theory management operations (name, identity, inclusion,
  2051     parents, ancestors, merge, etc.), plus generic theory data;
  2052 
  2053   Sign -- logical signature and syntax operations (declaring consts,
  2054     types, etc.), plus certify/read for common entities;
  2055 
  2056   Theory -- logical theory operations (stating axioms, definitions,
  2057     oracles), plus a copy of logical signature operations (consts,
  2058     types, etc.); also a few basic management operations (Theory.copy,
  2059     Theory.merge, etc.)
  2060 
  2061 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2062 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2063 for convenience -- they merely return the theory.
  2064 
  2065 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2066 
  2067 * Pure: the Isar proof context type is already defined early in Pure
  2068 as Context.proof (note that ProofContext.context and Proof.context are
  2069 aliases, where the latter is the preferred name).  This enables other
  2070 Isabelle components to refer to that type even before Isar is present.
  2071 
  2072 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2073 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2074 any of these kinds.  For example, Sign.intern typeK is now
  2075 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2076 Theory.hide_types.  Also note that former
  2077 Theory.hide_classes/types/consts are now
  2078 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2079 internalize their arguments!  INCOMPATIBILITY.
  2080 
  2081 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2082 datatype thmref (with constructors Name and NameSelection) instead of
  2083 plain string -- INCOMPATIBILITY;
  2084 
  2085 * Pure: cases produced by proof methods specify options, where NONE
  2086 means to remove case bindings -- INCOMPATIBILITY in
  2087 (RAW_)METHOD_CASES.
  2088 
  2089 * Pure: the following operations retrieve axioms or theorems from a
  2090 theory node or theory hierarchy, respectively:
  2091 
  2092   Theory.axioms_of: theory -> (string * term) list
  2093   Theory.all_axioms_of: theory -> (string * term) list
  2094   PureThy.thms_of: theory -> (string * thm) list
  2095   PureThy.all_thms_of: theory -> (string * thm) list
  2096 
  2097 * Pure: print_tac now outputs the goal through the trace channel.
  2098 
  2099 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2100 Reference Toplevel.debug (default false) controls detailed printing
  2101 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2102 controls execution profiling -- set to 1 for time and 2 for space
  2103 (both increase the runtime).
  2104 
  2105 * Isar session: The initial use of ROOT.ML is now always timed,
  2106 i.e. the log will show the actual process times, in contrast to the
  2107 elapsed wall-clock time that the outer shell wrapper produces.
  2108 
  2109 * Simplifier: improved handling of bound variables (nameless
  2110 representation, avoid allocating new strings).  Simprocs that invoke
  2111 the Simplifier recursively should use Simplifier.inherit_bounds to
  2112 avoid local name clashes.  Failure to do so produces warnings
  2113 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2114 for further details.
  2115 
  2116 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2117 bindings for all theorems stored within a given theory; this may help
  2118 in porting non-Isar theories to Isar ones, while keeping ML proof
  2119 scripts for the time being.
  2120 
  2121 * ML operator HTML.with_charset specifies the charset begin used for
  2122 generated HTML files.  For example:
  2123 
  2124   HTML.with_charset "utf-8" use_thy "Hebrew";
  2125   HTML.with_charset "utf-8" use_thy "Chinese";
  2126 
  2127 
  2128 *** System ***
  2129 
  2130 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2131 isabelle, isatool etc.).
  2132 
  2133 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2134 isatool doc, isatool mkdir, display_drafts etc.).
  2135 
  2136 * isatool usedir: option -f allows specification of the ML file to be
  2137 used by Isabelle; default is ROOT.ML.
  2138 
  2139 * New isatool version outputs the version identifier of the Isabelle
  2140 distribution being used.
  2141 
  2142 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2143 (containing Boolean satisfiability problems) into Isabelle/HOL
  2144 theories.
  2145 
  2146 
  2147 
  2148 New in Isabelle2004 (April 2004)
  2149 --------------------------------
  2150 
  2151 *** General ***
  2152 
  2153 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2154   Replaces linorder.ML.
  2155 
  2156 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2157   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2158   (\<a>...\<z>), are now considered normal letters, and can therefore
  2159   be used anywhere where an ASCII letter (a...zA...Z) has until
  2160   now. COMPATIBILITY: This obviously changes the parsing of some
  2161   terms, especially where a symbol has been used as a binder, say
  2162   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2163   as an identifier.  Fix it by inserting a space around former
  2164   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2165   existing theory and ML files.
  2166 
  2167 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2168 
  2169 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2170   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2171   a normal (but invisible) letter. For multiple letter subscripts repeat
  2172   \<^isub> like this: x\<^isub>1\<^isub>2.
  2173 
  2174 * Pure: There are now sub-/superscripts that can span more than one
  2175   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2176   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2177   superscript. The new control characters are not identifier parts.
  2178 
  2179 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2180   content of "..." to the latex file instead of \isacntrl... . The "..."
  2181   may consist of any printable characters excluding the end bracket >.
  2182 
  2183 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2184   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2185   declare constants "final", which prevents their being given a definition
  2186   later.  It is useful for constants whose behaviour is fixed axiomatically
  2187   rather than definitionally, such as the meta-logic connectives.
  2188 
  2189 * Pure: 'instance' now handles general arities with general sorts
  2190   (i.e. intersections of classes),
  2191 
  2192 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2193   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2194   It can be changed to alter the colors/layout of generated pages.
  2195 
  2196 
  2197 *** Isar ***
  2198 
  2199 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2200   cut_tac, subgoal_tac and thin_tac:
  2201   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2202     locales are no longer forced to write Isar proof scripts.
  2203     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2204     emulations.
  2205   - INCOMPATIBILITY: names of variables to be instantiated may no
  2206     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2207     This is consistent with the instantiation attribute "where".
  2208 
  2209 * Attributes "where" and "of":
  2210   - Now take type variables of instantiated theorem into account when reading
  2211     the instantiation string.  This fixes a bug that caused instantiated
  2212     theorems to have too special types in some circumstances.
  2213   - "where" permits explicit instantiations of type variables.
  2214 
  2215 * Calculation commands "moreover" and "also" no longer interfere with
  2216   current facts ("this"), admitting arbitrary combinations with "then"
  2217   and derived forms.
  2218 
  2219 * Locales:
  2220   - Goal statements involving the context element "includes" no longer
  2221     generate theorems with internal delta predicates (those ending on
  2222     "_axioms") in the premise.
  2223     Resolve particular premise with <locale>.intro to obtain old form.
  2224   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2225     specification and "includes" elements in goal statement.
  2226   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2227     [intro?] and [elim?] (respectively) by default.
  2228   - Experimental command for instantiation of locales in proof contexts:
  2229         instantiate <label>[<attrs>]: <loc>
  2230     Instantiates locale <loc> and adds all its theorems to the current context
  2231     taking into account their attributes.  Label and attrs are optional
  2232     modifiers, like in theorem declarations.  If present, names of
  2233     instantiated theorems are qualified with <label>, and the attributes
  2234     <attrs> are applied after any attributes these theorems might have already.
  2235       If the locale has assumptions, a chained fact of the form
  2236     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2237     are derived.  The command does not support old-style locales declared
  2238     with "locale (open)".
  2239       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2240 
  2241 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2242   (Isar) contexts.
  2243 
  2244 
  2245 *** HOL ***
  2246 
  2247 * Proof import: new image HOL4 contains the imported library from
  2248   the HOL4 system with about 2500 theorems. It is imported by
  2249   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2250   can be used like any other Isabelle image.  See
  2251   HOL/Import/HOL/README for more information.
  2252 
  2253 * Simplifier:
  2254   - Much improved handling of linear and partial orders.
  2255     Reasoners for linear and partial orders are set up for type classes
  2256     "linorder" and "order" respectively, and are added to the default simpset
  2257     as solvers.  This means that the simplifier can build transitivity chains
  2258     to solve goals from the assumptions.
  2259   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2260     of blast or auto after simplification become unnecessary because the goal
  2261     is solved by simplification already.
  2262 
  2263 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2264     all proved in axiomatic type classes for semirings, rings and fields.
  2265 
  2266 * Numerics:
  2267   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2268     now formalized using the Ring_and_Field theory mentioned above.
  2269   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2270     than before, because now they are set up once in a generic manner.
  2271   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2272     Look for the general versions in Ring_and_Field (and Power if they concern
  2273     exponentiation).
  2274 
  2275 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2276 
  2277 * Records:
  2278   - Record types are now by default printed with their type abbreviation
  2279     instead of the list of all field types. This can be configured via
  2280     the reference "print_record_type_abbr".
  2281   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2282     (not enabled by default).
  2283   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2284     EX x. x = sel r to True (not enabled by default).
  2285   - Tactic "record_split_simp_tac" to split and simplify records added.
  2286 
  2287 * 'specification' command added, allowing for definition by
  2288   specification.  There is also an 'ax_specification' command that
  2289   introduces the new constants axiomatically.
  2290 
  2291 * arith(_tac) is now able to generate counterexamples for reals as well.
  2292 
  2293 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2294 
  2295 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2296   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2297 
  2298 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2299   matrix theory to linear programming.
  2300 
  2301 * Unions and Intersections:
  2302   The latex output syntax of UN and INT has been changed
  2303   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2304   i.e. the index formulae has become a subscript.
  2305   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2306 
  2307 * Unions and Intersections over Intervals:
  2308   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2309   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2310   like in normal math, and corresponding versions for < and for intersection.
  2311 
  2312 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2313   lexicographic dictonary ordering has been added as "lexord".
  2314 
  2315 * ML: the legacy theory structures Int and List have been removed. They had
  2316   conflicted with ML Basis Library structures having the same names.
  2317 
  2318 * 'refute' command added to search for (finite) countermodels.  Only works
  2319   for a fragment of HOL.  The installation of an external SAT solver is
  2320   highly recommended.  See "HOL/Refute.thy" for details.
  2321 
  2322 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2323   formulae under an assignment of free variables to random values.
  2324   In contrast to 'refute', it can deal with inductive datatypes,
  2325   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2326   for examples.
  2327 
  2328 
  2329 *** HOLCF ***
  2330 
  2331 * Streams now come with concatenation and are part of the HOLCF image
  2332 
  2333 
  2334 
  2335 New in Isabelle2003 (May 2003)
  2336 ------------------------------
  2337 
  2338 *** General ***
  2339 
  2340 * Provers/simplifier:
  2341 
  2342   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2343     Assumptions are now subject to complete mutual simplification,
  2344     not just from left to right. The simplifier now preserves
  2345     the order of assumptions.
  2346 
  2347     Potential INCOMPATIBILITY:
  2348 
  2349     -- simp sometimes diverges where the old version did
  2350        not, e.g. invoking simp on the goal
  2351 
  2352         [| P (f x); y = x; f x = f y |] ==> Q
  2353 
  2354        now gives rise to the infinite reduction sequence
  2355 
  2356         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2357 
  2358        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2359        kind of problem.
  2360 
  2361     -- Tactics combining classical reasoner and simplification (such as auto)
  2362        are also affected by this change, because many of them rely on
  2363        simp. They may sometimes diverge as well or yield a different numbers
  2364        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2365        in case of problems. Sometimes subsequent calls to the classical
  2366        reasoner will fail because a preceeding call to the simplifier too
  2367        eagerly simplified the goal, e.g. deleted redundant premises.
  2368 
  2369   - The simplifier trace now shows the names of the applied rewrite rules
  2370 
  2371   - You can limit the number of recursive invocations of the simplifier
  2372     during conditional rewriting (where the simplifie tries to solve the
  2373     conditions before applying the rewrite rule):
  2374     ML "simp_depth_limit := n"
  2375     where n is an integer. Thus you can force termination where previously
  2376     the simplifier would diverge.
  2377 
  2378   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2379 
  2380   - No longer aborts on failed congruence proof.  Instead, the
  2381     congruence is ignored.
  2382 
  2383 * Pure: New generic framework for extracting programs from constructive
  2384   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2385   as HOL/Extraction for some case studies.
  2386 
  2387 * Pure: The main goal of the proof state is no longer shown by default, only
  2388 the subgoals. This behaviour is controlled by a new flag.
  2389    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2390 (ML: Proof.show_main_goal).
  2391 
  2392 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2393 rules whose conclusion matches subgoal 1:
  2394       PG menu: Isabelle/Isar -> Show me -> matching rules
  2395 The rules are ordered by how closely they match the subgoal.
  2396 In particular, rules that solve a subgoal outright are displayed first
  2397 (or rather last, the way they are printed).
  2398 (ML: ProofGeneral.print_intros())
  2399 
  2400 * Pure: New flag trace_unify_fail causes unification to print
  2401 diagnostic information (PG: in trace buffer) when it fails. This is
  2402 useful for figuring out why single step proofs like rule, erule or
  2403 assumption failed.
  2404 
  2405 * Pure: Locale specifications now produce predicate definitions
  2406 according to the body of text (covering assumptions modulo local
  2407 definitions); predicate "loc_axioms" covers newly introduced text,
  2408 while "loc" is cumulative wrt. all included locale expressions; the
  2409 latter view is presented only on export into the global theory
  2410 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2411 on the old view without predicates;
  2412 
  2413 * Pure: predefined locales "var" and "struct" are useful for sharing
  2414 parameters (as in CASL, for example); just specify something like
  2415 ``var x + var y + struct M'' as import;
  2416 
  2417 * Pure: improved thms_containing: proper indexing of facts instead of
  2418 raw theorems; check validity of results wrt. current name space;
  2419 include local facts of proof configuration (also covers active
  2420 locales), cover fixed variables in index; may use "_" in term
  2421 specification; an optional limit for the number of printed facts may
  2422 be given (the default is 40);
  2423 
  2424 * Pure: disallow duplicate fact bindings within new-style theory files
  2425 (batch-mode only);
  2426 
  2427 * Provers: improved induct method: assumptions introduced by case
  2428 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2429 the goal statement); "foo" still refers to all facts collectively;
  2430 
  2431 * Provers: the function blast.overloaded has been removed: all constants
  2432 are regarded as potentially overloaded, which improves robustness in exchange
  2433 for slight decrease in efficiency;
  2434 
  2435 * Provers/linorder: New generic prover for transitivity reasoning over
  2436 linear orders.  Note: this prover is not efficient!
  2437 
  2438 * Isar: preview of problems to finish 'show' now produce an error
  2439 rather than just a warning (in interactive mode);
  2440 
  2441 
  2442 *** HOL ***
  2443 
  2444 * arith(_tac)
  2445 
  2446  - Produces a counter example if it cannot prove a goal.
  2447    Note that the counter example may be spurious if the goal is not a formula
  2448    of quantifier-free linear arithmetic.
  2449    In ProofGeneral the counter example appears in the trace buffer.
  2450 
  2451  - Knows about div k and mod k where k is a numeral of type nat or int.
  2452 
  2453  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2454    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2455    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2456 
  2457 * simp's arithmetic capabilities have been enhanced a bit: it now
  2458 takes ~= in premises into account (by performing a case split);
  2459 
  2460 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2461 are distributed over a sum of terms;
  2462 
  2463 * New tactic "trans_tac" and method "trans" instantiate
  2464 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2465 "<=", "<" and "=").
  2466 
  2467 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2468 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2469 
  2470 * 'typedef' command has new option "open" to suppress the set
  2471 definition;
  2472 
  2473 * functions Min and Max on finite sets have been introduced (theory
  2474 Finite_Set);
  2475 
  2476 * attribute [symmetric] now works for relations as well; it turns
  2477 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2478 
  2479 * induct over a !!-quantified statement (say !!x1..xn):
  2480   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2481 
  2482 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2483 %x. None. Warning: empty_def now refers to the previously hidden definition
  2484 of the empty set.
  2485 
  2486 * Algebra: formalization of classical algebra.  Intended as base for
  2487 any algebraic development in Isabelle.  Currently covers group theory
  2488 (up to Sylow's theorem) and ring theory (Universal Property of
  2489 Univariate Polynomials).  Contributions welcome;
  2490 
  2491 * GroupTheory: deleted, since its material has been moved to Algebra;
  2492 
  2493 * Complex: new directory of the complex numbers with numeric constants,
  2494 nonstandard complex numbers, and some complex analysis, standard and
  2495 nonstandard (Jacques Fleuriot);
  2496 
  2497 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2498 
  2499 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2500 Fleuriot);
  2501 
  2502 * Real/HahnBanach: updated and adapted to locales;
  2503 
  2504 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2505 Gray and Kramer);
  2506 
  2507 * UNITY: added the Meier-Sanders theory of progress sets;
  2508 
  2509 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2510 as abstract algorithms, instantiated to the JVM;
  2511 
  2512 * Bali: Java source language formalization. Type system, operational
  2513 semantics, axiomatic semantics. Supported language features:
  2514 classes, interfaces, objects,virtual methods, static methods,
  2515 static/instance fields, arrays, access modifiers, definite
  2516 assignment, exceptions.
  2517 
  2518 
  2519 *** ZF ***
  2520 
  2521 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2522 universe, etc.);
  2523 
  2524 * Main ZF: virtually all theories converted to new-style format;
  2525 
  2526 
  2527 *** ML ***
  2528 
  2529 * Pure: Tactic.prove provides sane interface for internal proofs;
  2530 omits the infamous "standard" operation, so this is more appropriate
  2531 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2532 
  2533 * Pure: improved error reporting of simprocs;
  2534 
  2535 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2536 up simprocs;
  2537 
  2538 
  2539 *** Document preparation ***
  2540 
  2541 * uses \par instead of \\ for line breaks in theory text. This may
  2542 shift some page breaks in large documents. To get the old behaviour
  2543 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2544 
  2545 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2546 other packages
  2547 
  2548 * \<euro> now needs package babel/greek instead of marvosym (which
  2549 broke \Rightarrow)
  2550 
  2551 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2552 textcomp package)
  2553 
  2554 
  2555 
  2556 New in Isabelle2002 (March 2002)
  2557 --------------------------------
  2558 
  2559 *** Document preparation ***
  2560 
  2561 * greatly simplified document preparation setup, including more
  2562 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2563 instructive isatool mkdir; users should basically be able to get
  2564 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2565 users may run a separate document processing stage manually like this:
  2566 "isatool usedir -D output HOL Test && isatool document Test/output";
  2567 
  2568 * theory dependency graph may now be incorporated into documents;
  2569 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2570 with \includegraphics of LaTeX;
  2571 
  2572 * proper spacing of consecutive markup elements, especially text
  2573 blocks after section headings;
  2574 
  2575 * support bold style (for single symbols only), input syntax is like
  2576 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2577 
  2578 * \<bullet> is now output as bold \cdot by default, which looks much
  2579 better in printed text;
  2580 
  2581 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2582 note that these symbols are currently unavailable in Proof General /
  2583 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2584 
  2585 * isatool latex no longer depends on changed TEXINPUTS, instead
  2586 isatool document copies the Isabelle style files to the target
  2587 location;
  2588 
  2589 
  2590 *** Isar ***
  2591 
  2592 * Pure/Provers: improved proof by cases and induction;
  2593   - 'case' command admits impromptu naming of parameters (such as
  2594     "case (Suc n)");
  2595   - 'induct' method divinates rule instantiation from the inductive
  2596     claim; no longer requires excessive ?P bindings for proper
  2597     instantiation of cases;
  2598   - 'induct' method properly enumerates all possibilities of set/type
  2599     rules; as a consequence facts may be also passed through *type*
  2600     rules without further ado;
  2601   - 'induct' method now derives symbolic cases from the *rulified*
  2602     rule (before it used to rulify cases stemming from the internal
  2603     atomized version); this means that the context of a non-atomic
  2604     statement becomes is included in the hypothesis, avoiding the
  2605     slightly cumbersome show "PROP ?case" form;
  2606   - 'induct' may now use elim-style induction rules without chaining
  2607     facts, using ``missing'' premises from the goal state; this allows
  2608     rules stemming from inductive sets to be applied in unstructured
  2609     scripts, while still benefitting from proper handling of non-atomic
  2610     statements; NB: major inductive premises need to be put first, all
  2611     the rest of the goal is passed through the induction;
  2612   - 'induct' proper support for mutual induction involving non-atomic
  2613     rule statements (uses the new concept of simultaneous goals, see
  2614     below);
  2615   - append all possible rule selections, but only use the first
  2616     success (no backtracking);
  2617   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2618   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2619   - added 'print_induct_rules' (covered by help item in recent Proof
  2620     General versions);
  2621   - moved induct/cases attributes to Pure, methods to Provers;
  2622   - generic method setup instantiated for FOL and HOL;
  2623 
  2624 * Pure: support multiple simultaneous goal statements, for example
  2625 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2626 meta-level mechanism, this acts as if several individual goals had
  2627 been stated separately; in particular common proof methods need to be
  2628 repeated in order to cover all claims; note that a single elimination
  2629 step is *not* sufficient to establish the two conjunctions, so this
  2630 fails:
  2631 
  2632   assume "A & B" then have A and B ..   (*".." fails*)
  2633 
  2634 better use "obtain" in situations as above; alternative refer to
  2635 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2636 
  2637 * Pure: proper integration with ``locales''; unlike the original
  2638 version by Florian Kammller, Isar locales package high-level proof
  2639 contexts rather than raw logical ones (e.g. we admit to include
  2640 attributes everywhere); operations on locales include merge and
  2641 rename; support for implicit arguments (``structures''); simultaneous
  2642 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2643 some examples;
  2644 
  2645 * Pure: the following commands have been ``localized'', supporting a
  2646 target locale specification "(in name)": 'lemma', 'theorem',
  2647 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2648 stored both within the locale and at the theory level (exported and
  2649 qualified by the locale name);
  2650 
  2651 * Pure: theory goals may now be specified in ``long'' form, with
  2652 ad-hoc contexts consisting of arbitrary locale elements. for example
  2653 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2654 definitions may be given, too); the result is a meta-level rule with
  2655 the context elements being discharged in the obvious way;
  2656 
  2657 * Pure: new proof command 'using' allows to augment currently used
  2658 facts after a goal statement ('using' is syntactically analogous to
  2659 'apply', but acts on the goal's facts only); this allows chained facts
  2660 to be separated into parts given before and after a claim, as in
  2661 ``from a and b have C using d and e <proof>'';
  2662 
  2663 * Pure: renamed "antecedent" case to "rule_context";
  2664 
  2665 * Pure: new 'judgment' command records explicit information about the
  2666 object-logic embedding (used by several tools internally); no longer
  2667 use hard-wired "Trueprop";
  2668 
  2669 * Pure: added 'corollary' command;
  2670 
  2671 * Pure: fixed 'token_translation' command;
  2672 
  2673 * Pure: removed obsolete 'exported' attribute;
  2674 
  2675 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2676 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2677 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2678 
  2679 * Pure: method 'atomize' presents local goal premises as object-level
  2680 statements (atomic meta-level propositions); setup controlled via
  2681 rewrite rules declarations of 'atomize' attribute; example
  2682 application: 'induct' method with proper rule statements in improper
  2683 proof *scripts*;
  2684 
  2685 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2686 now consider the syntactic context of assumptions, giving a better
  2687 chance to get type-inference of the arguments right (this is
  2688 especially important for locales);
  2689 
  2690 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2691 mode;
  2692 
  2693 * Pure/obtain: the formal conclusion "thesis", being marked as
  2694 ``internal'', may no longer be reference directly in the text;
  2695 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2696 situations;
  2697 
  2698 * Pure: generic 'sym' attribute which declares a rule both as pure
  2699 'elim?' and for the 'symmetric' operation;
  2700 
  2701 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2702 text; the fixed correlation with particular command syntax has been
  2703 discontinued;
  2704 
  2705 * Pure: new method 'rules' is particularly well-suited for proof
  2706 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2707 but often produces more compact proof terms with less detours;
  2708 
  2709 * Pure/Provers/classical: simplified integration with pure rule
  2710 attributes and methods; the classical "intro?/elim?/dest?"
  2711 declarations coincide with the pure ones; the "rule" method no longer
  2712 includes classically swapped intros; "intro" and "elim" methods no
  2713 longer pick rules from the context; also got rid of ML declarations
  2714 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2715 INCOMPATIBILITY;
  2716 
  2717 * Provers/classical: attribute 'swapped' produces classical inversions
  2718 of introduction rules;
  2719 
  2720 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2721 rules instead of full simplifier context; 'iff' attribute handles
  2722 conditional rules;
  2723 
  2724 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2725 
  2726 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2727 "(permissive)" option to recover old behavior;
  2728 
  2729 * HOL: 'inductive' no longer features separate (collective) attributes
  2730 for 'intros' (was found too confusing);
  2731 
  2732 * HOL: properly declared induction rules less_induct and
  2733 wf_induct_rule;
  2734 
  2735 
  2736 *** HOL ***
  2737 
  2738 * HOL: moved over to sane numeral syntax; the new policy is as
  2739 follows:
  2740 
  2741   - 0 and 1 are polymorphic constants, which are defined on any
  2742   numeric type (nat, int, real etc.);
  2743 
  2744   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2745   binary representation internally;
  2746 
  2747   - type nat has special constructor Suc, and generally prefers Suc 0
  2748   over 1::nat and Suc (Suc 0) over 2::nat;
  2749 
  2750 This change may cause significant problems of INCOMPATIBILITY; here
  2751 are some hints on converting existing sources:
  2752 
  2753   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2754   entities, so expressions involving "-" (unary or binary minus) need
  2755   to be spaced properly;
  2756 
  2757   - existing occurrences of "1" may need to be constraint "1::nat" or
  2758   even replaced by Suc 0; similar for old "2";
  2759 
  2760   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2761 
  2762   - remove all special provisions on numerals in proofs;
  2763 
  2764 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2765 representation (depends on bin_arith_simps in the default context);
  2766 
  2767 * HOL: symbolic syntax for x^2 (numeral 2);
  2768 
  2769 * HOL: the class of all HOL types is now called "type" rather than
  2770 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2771 in axclass/classes, instance/arities, and (usually rare) occurrences
  2772 in typings (of consts etc.); internally the class is called
  2773 "HOL.type", ML programs should refer to HOLogic.typeS;
  2774 
  2775 * HOL/record package improvements:
  2776   - new derived operations "fields" to build a partial record section,
  2777     "extend" to promote a fixed record to a record scheme, and
  2778     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2779     declared as simp by default;
  2780   - shared operations ("more", "fields", etc.) now need to be always
  2781     qualified) --- potential INCOMPATIBILITY;
  2782   - removed "make_scheme" operations (use "make" with "extend") --
  2783     INCOMPATIBILITY;
  2784   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2785   - provides cases/induct rules for use with corresponding Isar
  2786     methods (for concrete records, record schemes, concrete more
  2787     parts, and schematic more parts -- in that order);
  2788   - internal definitions directly based on a light-weight abstract
  2789     theory of product types over typedef rather than datatype;
  2790 
  2791 * HOL: generic code generator for generating executable ML code from
  2792 specifications; specific support for HOL constructs such as inductive
  2793 datatypes and sets, as well as recursive functions; can be invoked
  2794 via 'generate_code' theory section;
  2795 
  2796 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2797 
  2798 * HOL: consolidated and renamed several theories.  In particular:
  2799         Ord.thy has been absorbed into HOL.thy
  2800         String.thy has been absorbed into List.thy
  2801 
  2802 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2803 (beware of argument permutation!);
  2804 
  2805 * HOL: linorder_less_split superseded by linorder_cases;
  2806 
  2807 * HOL/List: "nodups" renamed to "distinct";
  2808 
  2809 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2810 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2811   - Ex_def has changed, now need to use some_eq_ex
  2812 
  2813 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2814 in this (rare) case use:
  2815 
  2816   delSWrapper "split_all_tac"
  2817   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2818 
  2819 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2820 MAY FAIL;
  2821 
  2822 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2823 Isabelle's type classes, ^ on functions and relations has too general
  2824 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2825 necessary to attach explicit type constraints;
  2826 
  2827 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2828 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2829 renamed accordingly (eg "compI" -> "rel_compI").
  2830 
  2831 * HOL: syntax translations now work properly with numerals and records
  2832 expressions;
  2833 
  2834 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2835 of "lam" -- INCOMPATIBILITY;
  2836 
  2837 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2838 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2839 renamed "Product_Type.unit";
  2840 
  2841 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2842 
  2843 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2844 the "cases" method);
  2845 
  2846 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2847 Florian Kammller);
  2848 
  2849 * HOL/IMP: updated and converted to new-style theory format; several
  2850 parts turned into readable document, with proper Isar proof texts and
  2851 some explanations (by Gerwin Klein);
  2852 
  2853 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2854 
  2855 * HOL-Hyperreal is now a logic image;
  2856 
  2857 
  2858 *** HOLCF ***
  2859 
  2860 * Isar: consts/constdefs supports mixfix syntax for continuous
  2861 operations;
  2862 
  2863 * Isar: domain package adapted to new-style theory format, e.g. see
  2864 HOLCF/ex/Dnat.thy;
  2865 
  2866 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2867 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2868 lift.induct_tac, always use UU instead of Undef;
  2869 
  2870 * HOLCF/IMP: updated and converted to new-style theory;
  2871 
  2872 
  2873 *** ZF ***
  2874 
  2875 * Isar: proper integration of logic-specific tools and packages,
  2876 including theory commands '(co)inductive', '(co)datatype',
  2877 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2878 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2879 
  2880 * theory Main no longer includes AC; for the Axiom of Choice, base
  2881 your theory on Main_ZFC;
  2882 
  2883 * the integer library now covers quotients and remainders, with many
  2884 laws relating division to addition, multiplication, etc.;
  2885 
  2886 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2887 typeless version of the formalism;
  2888 
  2889 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2890 format;
  2891 
  2892 * ZF/Induct: new directory for examples of inductive definitions,
  2893 including theory Multiset for multiset orderings; converted to
  2894 new-style theory format;
  2895 
  2896 * ZF: many new theorems about lists, ordinals, etc.;
  2897 
  2898 
  2899 *** General ***
  2900 
  2901 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2902 variable proof controls level of detail: 0 = no proofs (only oracle
  2903 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2904 also ref manual for further ML interfaces;
  2905 
  2906 * Pure/axclass: removed obsolete ML interface
  2907 goal_subclass/goal_arity;
  2908 
  2909 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2910 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2911 separate tokens, so expressions involving minus need to be spaced
  2912 properly;
  2913 
  2914 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2915 rather than "infixl" or "infixr";
  2916 
  2917 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2918 sort constraint specifications in type inference; e.g. "x::_::foo"
  2919 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2920 type variable);
  2921 
  2922 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2923 control output of nested => (types); the default behavior is
  2924 "type_brackets";
  2925 
  2926 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2927 tokens into AST constants;
  2928 
  2929 * Pure/syntax: prefer later declarations of translations and print
  2930 translation functions; potential INCOMPATIBILITY: need to reverse
  2931 multiple declarations for same syntax element constant;
  2932 
  2933 * Pure/show_hyps reset by default (in accordance to existing Isar
  2934 practice);
  2935 
  2936 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2937 addSafter;
  2938 
  2939 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2940 as well;
  2941 
  2942 * system: tested support for MacOS X; should be able to get Isabelle +
  2943 Proof General to work in a plain Terminal after installing Poly/ML
  2944 (e.g. from the Isabelle distribution area) and GNU bash alone
  2945 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2946 support requires further installations, e.g. from
  2947 http://fink.sourceforge.net/);
  2948 
  2949 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2950 
  2951 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2952 of 40 MB), cf. ML_OPTIONS;
  2953 
  2954 * system: Proof General keywords specification is now part of the
  2955 Isabelle distribution (see etc/isar-keywords.el);
  2956 
  2957 * system: support for persistent Proof General sessions (refrain from
  2958 outdating all loaded theories on startup); user may create writable
  2959 logic images like this: ``isabelle -q HOL Test'';
  2960 
  2961 * system: smart selection of Isabelle process versus Isabelle
  2962 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2963 run both "isabelle" and "Isabelle" even if file names are badly
  2964 damaged (executable inspects the case of the first letter of its own
  2965 name); added separate "isabelle-process" and "isabelle-interface";
  2966 
  2967 * system: refrain from any attempt at filtering input streams; no
  2968 longer support ``8bit'' encoding of old isabelle font, instead proper
  2969 iso-latin characters may now be used; the related isatools
  2970 "symbolinput" and "nonascii" have disappeared as well;
  2971 
  2972 * system: removed old "xterm" interface (the print modes "xterm" and
  2973 "xterm_color" are still available for direct use in a suitable
  2974 terminal);
  2975 
  2976 
  2977 
  2978 New in Isabelle99-2 (February 2001)
  2979 -----------------------------------
  2980 
  2981 *** Overview of INCOMPATIBILITIES ***
  2982 
  2983 * HOL: please note that theories in the Library and elsewhere often use the
  2984 new-style (Isar) format; to refer to their theorems in an ML script you must
  2985 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2986 
  2987 * HOL: inductive package no longer splits induction rule aggressively,
  2988 but only as far as specified by the introductions given; the old
  2989 format may be recovered via ML function complete_split_rule or attribute
  2990 'split_rule (complete)';
  2991 
  2992 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2993 gfp_Tarski to gfp_unfold;
  2994 
  2995 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2996 
  2997 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2998 relation); infix "^^" has been renamed "``"; infix "``" has been
  2999 renamed "`"; "univalent" has been renamed "single_valued";
  3000 
  3001 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3002 operation;
  3003 
  3004 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3005 
  3006 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3007 
  3008 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3009 consequence, it is no longer monotonic wrt. the local goal context
  3010 (which is now passed through the inductive cases);
  3011 
  3012 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3013 \<gg> to \<ggreater>;
  3014 
  3015 
  3016 *** Document preparation ***
  3017 
  3018 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3019 available: are "it" for near math-mode best-style output, "sl" for
  3020 slanted text style, and "tt" for plain type-writer; if no
  3021 \isabellestyle command is given, output is according to slanted
  3022 type-writer);
  3023 
  3024 * support sub/super scripts (for single symbols only), input syntax is
  3025 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3026 
  3027 * some more standard symbols; see Appendix A of the system manual for
  3028 the complete list of symbols defined in isabellesym.sty;
  3029 
  3030 * improved isabelle style files; more abstract symbol implementation
  3031 (should now use \isamath{...} and \isatext{...} in custom symbol
  3032 definitions);
  3033 
  3034 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3035 state; Note that presentation of goal states does not conform to
  3036 actual human-readable proof documents.  Please do not include goal
  3037 states into document output unless you really know what you are doing!
  3038 
  3039 * proper indentation of antiquoted output with proportional LaTeX
  3040 fonts;
  3041 
  3042 * no_document ML operator temporarily disables LaTeX document
  3043 generation;
  3044 
  3045 * isatool unsymbolize tunes sources for plain ASCII communication;
  3046 
  3047 
  3048 *** Isar ***
  3049 
  3050 * Pure: Isar now suffers initial goal statements to contain unbound
  3051 schematic variables (this does not conform to actual readable proof
  3052 documents, due to unpredictable outcome and non-compositional proof
  3053 checking); users who know what they are doing may use schematic goals
  3054 for Prolog-style synthesis of proven results;
  3055 
  3056 * Pure: assumption method (an implicit finishing) now handles actual
  3057 rules as well;
  3058 
  3059 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3060 initial goal, declare "that" only as Pure intro (only for single
  3061 steps); the "that" rule assumption may now be involved in implicit
  3062 finishing, thus ".." becomes a feasible for trivial obtains;
  3063 
  3064 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3065 instance proofs may be performed by "..";
  3066 
  3067 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3068 statements as well;
  3069 
  3070 * Pure: more robust selection of calculational rules;
  3071 
  3072 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3073 rule (as well as the assumption rule);
  3074 
  3075 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3076 lemmas, using the graph browser tool;
  3077 
  3078 * Pure: predict failure of "show" in interactive mode;
  3079 
  3080 * Pure: 'thms_containing' now takes actual terms as arguments;
  3081 
  3082 * HOL: improved method 'induct' --- now handles non-atomic goals
  3083 (potential INCOMPATIBILITY); tuned error handling;
  3084 
  3085 * HOL: cases and induct rules now provide explicit hints about the
  3086 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3087 any remaining facts are inserted into the goal verbatim;
  3088 
  3089 * HOL: local contexts (aka cases) may now contain term bindings as
  3090 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3091 the result to be shown in each case;
  3092 
  3093 * HOL: added 'recdef_tc' command;
  3094 
  3095 * isatool convert assists in eliminating legacy ML scripts;
  3096 
  3097 
  3098 *** HOL ***
  3099 
  3100 * HOL/Library: a collection of generic theories to be used together
  3101 with main HOL; the theory loader path already includes this directory
  3102 by default; the following existing theories have been moved here:
  3103 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3104 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3105 
  3106 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3107 modelling and verification task performed in Isabelle/HOL +
  3108 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3109 
  3110 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3111 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3112 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3113 'domain', this makes the theory consistent with mathematical
  3114 literature;
  3115 
  3116 * HOL basics: added overloaded operations "inverse" and "divide"
  3117 (infix "/"), syntax for generic "abs" operation, generic summation
  3118 operator \<Sum>;
  3119 
  3120 * HOL/typedef: simplified package, provide more useful rules (see also
  3121 HOL/subset.thy);
  3122 
  3123 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3124 now expressed as a proper nested rule (old-style tactic scripts may
  3125 require atomize_strip_tac to cope with non-atomic premises);
  3126 
  3127 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3128 to "split_conv" (old name still available for compatibility);
  3129 
  3130 * HOL: improved concrete syntax for strings (e.g. allows translation
  3131 rules with string literals);
  3132 
  3133 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3134  and Fleuriot's mechanization of analysis, including the transcendental
  3135  functions for the reals;
  3136 
  3137 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3138 
  3139 
  3140 *** CTT ***
  3141 
  3142 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3143 "lam" is displayed as TWO lambda-symbols
  3144 
  3145 * CTT: theory Main now available, containing everything (that is, Bool
  3146 and Arith);
  3147 
  3148 
  3149 *** General ***
  3150 
  3151 * Pure: the Simplifier has been implemented properly as a derived rule
  3152 outside of the actual kernel (at last!); the overall performance
  3153 penalty in practical applications is about 50%, while reliability of
  3154 the Isabelle inference kernel has been greatly improved;
  3155 
  3156 * print modes "brackets" and "no_brackets" control output of nested =>
  3157 (types) and ==> (props); the default behaviour is "brackets";
  3158 
  3159 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3160 as assumptions as well;
  3161 
  3162 * system: support Poly/ML 4.0;
  3163 
  3164 * system: isatool install handles KDE version 1 or 2;
  3165 
  3166 
  3167 
  3168 New in Isabelle99-1 (October 2000)
  3169 ----------------------------------
  3170 
  3171 *** Overview of INCOMPATIBILITIES ***
  3172 
  3173 * HOL: simplification of natural numbers is much changed; to partly
  3174 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3175 issue the following ML commands:
  3176 
  3177   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3178   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3179 
  3180 * HOL: simplification no longer dives into case-expressions; this is
  3181 controlled by "t.weak_case_cong" for each datatype t;
  3182 
  3183 * HOL: nat_less_induct renamed to less_induct;
  3184 
  3185 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3186 fixsome to patch .thy and .ML sources automatically;
  3187 
  3188   select_equality  -> some_equality
  3189   select_eq_Ex     -> some_eq_ex
  3190   selectI2EX       -> someI2_ex
  3191   selectI2         -> someI2
  3192   selectI          -> someI
  3193   select1_equality -> some1_equality
  3194   Eps_sym_eq       -> some_sym_eq_trivial
  3195   Eps_eq           -> some_eq_trivial
  3196 
  3197 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3198 
  3199 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3200 instead);
  3201 
  3202 * HOL: the recursion equations generated by 'recdef' are now called
  3203 f.simps instead of f.rules;
  3204 
  3205 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3206 
  3207 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3208 sometimes be needed;
  3209 
  3210 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3211 
  3212 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3213 
  3214 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3215 product is now "<*>" instead of "Times"; the lexicographic product is
  3216 now "<*lex*>" instead of "**";
  3217 
  3218 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3219 of main HOL, but was unused); better use HOL's datatype package;
  3220 
  3221 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3222 the old syntax may be recovered as follows:
  3223 
  3224   syntax (symbols)
  3225     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3226       (infixl "\\<oplus>" 100)
  3227 
  3228 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3229 
  3230 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3231 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3232 internally;
  3233 
  3234 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3235 changed from A/r to A//r;
  3236 
  3237 * ZF: new treatment of arithmetic (nat & int) may break some old
  3238 proofs;
  3239 
  3240 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3241 rulify -> rule_format, elimify -> elim_format, ...);
  3242 
  3243 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3244 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3245 should have to change intro!! to intro? only); replaced "delrule" by
  3246 "rule del";
  3247 
  3248 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3249 
  3250 * Provers: strengthened force_tac by using new first_best_tac;
  3251 
  3252 * LaTeX document preparation: several changes of isabelle.sty (see
  3253 lib/texinputs);
  3254 
  3255 
  3256 *** Document preparation ***
  3257 
  3258 * formal comments (text blocks etc.) in new-style theories may now
  3259 contain antiquotations of thm/prop/term/typ/text to be presented
  3260 according to latex print mode; concrete syntax is like this:
  3261 @{term[show_types] "f(x) = a + x"};
  3262 
  3263 * isatool mkdir provides easy setup of Isabelle session directories,
  3264 including proper document sources;
  3265 
  3266 * generated LaTeX sources are now deleted after successful run
  3267 (isatool document -c); may retain a copy somewhere else via -D option
  3268 of isatool usedir;
  3269 
  3270 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3271 style files, achieving self-contained LaTeX sources and simplifying
  3272 LaTeX debugging;
  3273 
  3274 * old-style theories now produce (crude) LaTeX output as well;
  3275 
  3276 * browser info session directories are now self-contained (may be put
  3277 on WWW server seperately); improved graphs of nested sessions; removed
  3278 graph for 'all sessions';
  3279 
  3280 * several improvements in isabelle style files; \isabellestyle{it}
  3281 produces fake math mode output; \isamarkupheader is now \section by
  3282 default; see lib/texinputs/isabelle.sty etc.;
  3283 
  3284 
  3285 *** Isar ***
  3286 
  3287 * Isar/Pure: local results and corresponding term bindings are now
  3288 subject to Hindley-Milner polymorphism (similar to ML); this
  3289 accommodates incremental type-inference very nicely;
  3290 
  3291 * Isar/Pure: new derived language element 'obtain' supports
  3292 generalized existence reasoning;
  3293 
  3294 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3295 support accumulation of results, without applying any rules yet;
  3296 useful to collect intermediate results without explicit name
  3297 references, and for use with transitivity rules with more than 2
  3298 premises;
  3299 
  3300 * Isar/Pure: scalable support for case-analysis type proofs: new
  3301 'case' language element refers to local contexts symbolically, as
  3302 produced by certain proof methods; internally, case names are attached
  3303 to theorems as "tags";
  3304 
  3305 * Isar/Pure: theory command 'hide' removes declarations from
  3306 class/type/const name spaces;
  3307 
  3308 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3309 indicate potential overloading;
  3310 
  3311 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3312 
  3313 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3314 "{a,b,c}" instead of {a,b,c};
  3315 
  3316 * Isar/Pure now provides its own version of intro/elim/dest
  3317 attributes; useful for building new logics, but beware of confusion
  3318 with the version in Provers/classical;
  3319 
  3320 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3321 case name 'antecedent';
  3322 
  3323 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3324 to the current context is now done automatically);
  3325 
  3326 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3327 for definining proof methods in ML;
  3328 
  3329 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3330 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3331 most cases, one should have to change intro!! to intro? only);
  3332 replaced "delrule" by "rule del";
  3333 
  3334 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3335 'symmetric' attribute (the latter supercedes [RS sym]);
  3336 
  3337 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3338 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3339 well (including splits);
  3340 
  3341 * Isar/Provers: Simplifier and Classical methods now support all kind
  3342 of modifiers used in the past, including 'cong', 'iff', etc.
  3343 
  3344 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3345 of Simplifier and Classical reasoner);
  3346 
  3347 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3348 now support named cases; major packages (inductive, datatype, primrec,
  3349 recdef) support case names and properly name parameters;
  3350 
  3351 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3352 monotonicity conditions are extracted to be proven at end of
  3353 calculations;
  3354 
  3355 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3356 method anyway;
  3357 
  3358 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3359 split_if split_if_asm; datatype package provides theorems foo.splits =
  3360 foo.split foo.split_asm for each datatype;
  3361 
  3362 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3363 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3364 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3365 use "(cases (simplified))" method in proper proof texts);
  3366 
  3367 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3368 
  3369 * Isar: names of theorems etc. may be natural numbers as well;
  3370 
  3371 * Isar: 'pr' command: optional arguments for goals_limit and
  3372 ProofContext.prems_limit; no longer prints theory contexts, but only
  3373 proof states;
  3374 
  3375 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3376 additional print modes to be specified; e.g. "pr(latex)" will print
  3377 proof state according to the Isabelle LaTeX style;
  3378 
  3379 * Isar: improved support for emulating tactic scripts, including proof
  3380 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3381 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3382 (for HOL datatypes);
  3383 
  3384 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3385 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3386 'proof method scripts' have to be in depth-first order;
  3387 
  3388 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3389 
  3390 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3391 should instead use individual commands for printing items
  3392 (print_commands, print_methods etc.);
  3393 
  3394 * Isar: added 'nothing' --- the empty list of theorems;
  3395 
  3396 
  3397 *** HOL ***
  3398 
  3399 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3400 corresponding virtual machine and a specification of its bytecode
  3401 verifier and a lightweight bytecode verifier, including proofs of
  3402 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3403 Cornelia Pusch (see also the homepage of project Bali at
  3404 http://isabelle.in.tum.de/Bali/);
  3405 
  3406 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3407 Clemens Ballarin;
  3408 
  3409 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3410 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3411 Rasmussen;
  3412 
  3413 * HOL/Lattice: fundamental concepts of lattice theory and order
  3414 structures, including duals, properties of bounds versus algebraic
  3415 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3416 Theorem for complete lattices etc.; may also serve as a demonstration
  3417 for abstract algebraic reasoning using axiomatic type classes, and
  3418 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3419 
  3420 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3421 von Oheimb;
  3422 
  3423 * HOL/IMPP: extension of IMP with local variables and mutually
  3424 recursive procedures, by David von Oheimb;
  3425 
  3426 * HOL/Lambda: converted into new-style theory and document;
  3427 
  3428 * HOL/ex/Multiquote: example of multiple nested quotations and
  3429 anti-quotations -- basically a generalized version of de-Bruijn
  3430 representation; very useful in avoiding lifting of operations;
  3431 
  3432 * HOL/record: added general record equality rule to simpset; fixed
  3433 select-update simplification procedure to handle extended records as
  3434 well; admit "r" as field name;
  3435 
  3436 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3437 other numeric types and also as the identity of groups, rings, etc.;
  3438 
  3439 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3440 Types nat and int belong to this axclass;
  3441 
  3442 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3443    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3444    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3445   two terms #m*u and #n*u are replaced by #(m+n)*u
  3446     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3447   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3448     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3449 
  3450 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3451 powerful prover for predicate logic but knows nothing of clasets; see
  3452 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3453 
  3454 * HOL: new version of "case_tac" subsumes both boolean case split and
  3455 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3456 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3457 
  3458 * HOL: simplification no longer dives into case-expressions: only the
  3459 selector expression is simplified, but not the remaining arms; to
  3460 enable full simplification of case-expressions for datatype t, you may
  3461 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3462 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3463 
  3464 * HOL/recdef: the recursion equations generated by 'recdef' for
  3465 function 'f' are now called f.simps instead of f.rules; if all
  3466 termination conditions are proved automatically, these simplification
  3467 rules are added to the simpset, as in primrec; rules may be named
  3468 individually as well, resulting in a separate list of theorems for
  3469 each equation;
  3470 
  3471 * HOL/While is a new theory that provides a while-combinator. It
  3472 permits the definition of tail-recursive functions without the
  3473 provision of a termination measure. The latter is necessary once the
  3474 invariant proof rule for while is applied.
  3475 
  3476 * HOL: new (overloaded) notation for the set of elements below/above
  3477 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3478 
  3479 * HOL: theorems impI, allI, ballI bound as "strip";
  3480 
  3481 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3482 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3483 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3484 
  3485 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3486 
  3487 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3488 main HOL, but was unused);
  3489 
  3490 * HOL: fewer consts declared as global (e.g. have to refer to
  3491 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3492 
  3493 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3494 in case of overlap with user translations (e.g. judgements over
  3495 tuples); (note that the underlying logical represenation is still
  3496 bogus);
  3497 
  3498 
  3499 *** ZF ***
  3500 
  3501 * ZF: simplification automatically cancels common terms in arithmetic
  3502 expressions over nat and int;
  3503 
  3504 * ZF: new treatment of nat to minimize type-checking: all operators
  3505 coerce their operands to a natural number using the function natify,
  3506 making the algebraic laws unconditional;
  3507 
  3508 * ZF: as above, for int: operators coerce their operands to an integer
  3509 using the function intify;
  3510 
  3511 * ZF: the integer library now contains many of the usual laws for the
  3512 orderings, including $<=, and monotonicity laws for $+ and $*;
  3513 
  3514 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3515 simplification;
  3516 
  3517 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3518 to the simplifier and classical reasoner simultaneously;
  3519 
  3520 
  3521 *** General ***
  3522 
  3523 * Provers: blast_tac now handles actual object-logic rules as
  3524 assumptions; note that auto_tac uses blast_tac internally as well;
  3525 
  3526 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3527 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3528 
  3529 * Provers: delrules now handles destruct rules as well (no longer need
  3530 explicit make_elim);
  3531 
  3532 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3533   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3534 use instead the strong form,
  3535   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3536 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3537 from destruct-rules;
  3538 
  3539 * Provers: Simplifier.easy_setup provides a fast path to basic
  3540 Simplifier setup for new object-logics;
  3541 
  3542 * Pure: AST translation rules no longer require constant head on LHS;
  3543 
  3544 * Pure: improved name spaces: ambiguous output is qualified; support
  3545 for hiding of names;
  3546 
  3547 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3548 XSYMBOL_HOME; no longer need to do manual configuration in most
  3549 situations;
  3550 
  3551 * system: compression of ML heaps images may now be controlled via -c
  3552 option of isabelle and isatool usedir (currently only observed by
  3553 Poly/ML);
  3554 
  3555 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3556 useful for remote X11);
  3557 
  3558 * system: provide TAGS file for Isabelle sources;
  3559 
  3560 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3561 order;
  3562 
  3563 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3564 timing flag supersedes proof_timing and Toplevel.trace;
  3565 
  3566 * ML: new combinators |>> and |>>> for incremental transformations
  3567 with secondary results (e.g. certain theory extensions):
  3568 
  3569 * ML: PureThy.add_defs gets additional argument to indicate potential
  3570 overloading (usually false);
  3571 
  3572 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3573 results;
  3574 
  3575 
  3576 
  3577 New in Isabelle99 (October 1999)
  3578 --------------------------------
  3579 
  3580 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3581 
  3582 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3583 are no longer simplified.  (This allows the simplifier to unfold recursive
  3584 functional programs.)  To restore the old behaviour, declare
  3585 
  3586     Delcongs [if_weak_cong];
  3587 
  3588 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3589 complement;
  3590 
  3591 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3592 
  3593 * HOL/datatype: mutual_induct_tac no longer exists --
  3594   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3595 
  3596 * HOL/typedef: fixed type inference for representing set; type
  3597 arguments now have to occur explicitly on the rhs as type constraints;
  3598 
  3599 * ZF: The con_defs part of an inductive definition may no longer refer
  3600 to constants declared in the same theory;
  3601 
  3602 * HOL, ZF: the function mk_cases, generated by the inductive
  3603 definition package, has lost an argument.  To simplify its result, it
  3604 uses the default simpset instead of a supplied list of theorems.
  3605 
  3606 * HOL/List: the constructors of type list are now Nil and Cons;
  3607 
  3608 * Simplifier: the type of the infix ML functions
  3609         setSSolver addSSolver setSolver addSolver
  3610 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3611 for packaging solvers. A solver is created via
  3612         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3613 where the string argument is only a comment.
  3614 
  3615 
  3616 *** Proof tools ***
  3617 
  3618 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3619 decision procedure for linear arithmetic. Currently it is used for
  3620 types `nat', `int', and `real' in HOL (see below); it can, should and
  3621 will be instantiated for other types and logics as well.
  3622 
  3623 * The simplifier now accepts rewrite rules with flexible heads, eg
  3624      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3625   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3626   matching.
  3627 
  3628 
  3629 *** General ***
  3630 
  3631 * New Isabelle/Isar subsystem provides an alternative to traditional
  3632 tactical theorem proving; together with the ProofGeneral/isar user
  3633 interface it offers an interactive environment for developing human
  3634 readable proof documents (Isar == Intelligible semi-automated
  3635 reasoning); for further information see isatool doc isar-ref,
  3636 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3637 
  3638 * improved and simplified presentation of theories: better HTML markup
  3639 (including colors), graph views in several sizes; isatool usedir now
  3640 provides a proper interface for user theories (via -P option); actual
  3641 document preparation based on (PDF)LaTeX is available as well (for
  3642 new-style theories only); see isatool doc system for more information;
  3643 
  3644 * native support for Proof General, both for classic Isabelle and
  3645 Isabelle/Isar;
  3646 
  3647 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3648 using the graph browser tool;
  3649 
  3650 * Isabelle manuals now also available as PDF;
  3651 
  3652 * theory loader rewritten from scratch (may not be fully
  3653 bug-compatible); old loadpath variable has been replaced by show_path,
  3654 add_path, del_path, reset_path functions; new operations such as
  3655 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3656 isatool doc ref);
  3657 
  3658 * improved isatool install: option -k creates KDE application icon,
  3659 option -p DIR installs standalone binaries;
  3660 
  3661 * added ML_PLATFORM setting (useful for cross-platform installations);
  3662 more robust handling of platform specific ML images for SML/NJ;
  3663 
  3664 * the settings environment is now statically scoped, i.e. it is never
  3665 created again in sub-processes invoked from isabelle, isatool, or
  3666 Isabelle;
  3667 
  3668 * path element specification '~~' refers to '$ISABELLE_HOME';
  3669 
  3670 * in locales, the "assumes" and "defines" parts may be omitted if
  3671 empty;
  3672 
  3673 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3674 long arrows);
  3675 
  3676 * new print_mode "HTML";
  3677 
  3678 * new flag show_tags controls display of tags of theorems (which are
  3679 basically just comments that may be attached by some tools);
  3680 
  3681 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3682 mode and goal output format:
  3683 
  3684 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3685 244c244
  3686 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3687 ---
  3688 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3689 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3690 181c181
  3691 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3692 ---
  3693 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3694 
  3695 * function bind_thms stores lists of theorems (cf. bind_thm);
  3696 
  3697 * new shorthand tactics ftac, eatac, datac, fatac;
  3698 
  3699 * qed (and friends) now accept "" as result name; in that case the
  3700 theorem is not stored, but proper checks and presentation of the
  3701 result still apply;
  3702 
  3703 * theorem database now also indexes constants "Trueprop", "all",
  3704 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3705 
  3706 
  3707 *** HOL ***
  3708 
  3709 ** HOL arithmetic **
  3710 
  3711 * There are now decision procedures for linear arithmetic over nat and
  3712 int:
  3713 
  3714 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3715 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3716 are treated as atomic; subformulae not involving type `nat' or `int'
  3717 are ignored; quantified subformulae are ignored unless they are
  3718 positive universal or negative existential. The tactic has to be
  3719 invoked by hand and can be a little bit slow. In particular, the
  3720 running time is exponential in the number of occurrences of `min' and
  3721 `max', and `-' on `nat'.
  3722 
  3723 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3724 (negated) (in)equalities among the premises and the conclusion into
  3725 account (i.e. no compound formulae) and does not know about `min' and
  3726 `max', and `-' on `nat'. It is fast and is used automatically by the
  3727 simplifier.
  3728 
  3729 NB: At the moment, these decision procedures do not cope with mixed
  3730 nat/int formulae where the two parts interact, such as `m < n ==>
  3731 int(m) < int(n)'.
  3732 
  3733 * HOL/Numeral provides a generic theory of numerals (encoded
  3734 efficiently as bit strings); setup for types nat/int/real is in place;
  3735 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3736 int, existing theories and proof scripts may require a few additional
  3737 type constraints;
  3738 
  3739 * integer division and remainder can now be performed on constant
  3740 arguments;
  3741 
  3742 * many properties of integer multiplication, division and remainder
  3743 are now available;
  3744 
  3745 * An interface to the Stanford Validity Checker (SVC) is available through the
  3746 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3747 are proved automatically.  SVC must be installed separately, and its results
  3748 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3749 invocation of the underlying oracle).  For SVC see
  3750   http://verify.stanford.edu/SVC
  3751 
  3752 * IsaMakefile: the HOL-Real target now builds an actual image;
  3753 
  3754 
  3755 ** HOL misc **
  3756 
  3757 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3758 (in Isabelle/Isar) -- by Gertrud Bauer;
  3759 
  3760 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3761 analysis for assembly languages with subtypes;
  3762 
  3763 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3764 -- avoids syntactic ambiguities and treats state, transition, and
  3765 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3766 changed syntax and (many) tactics;
  3767 
  3768 * HOL/inductive: Now also handles more general introduction rules such
  3769   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3770   theorems are now maintained within the theory (maintained via the
  3771   "mono" attribute);
  3772 
  3773 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3774   (using function types) such as
  3775 
  3776   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3777 
  3778 * HOL/record: record_simproc (part of the default simpset) takes care
  3779 of selectors applied to updated records; record_split_tac is no longer
  3780 part of the default claset; update_defs may now be removed from the
  3781 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3782 
  3783   claset_ref () := claset() addSWrapper record_split_wrapper;
  3784   Delsimprocs [record_simproc]
  3785 
  3786 * HOL/typedef: fixed type inference for representing set; type
  3787 arguments now have to occur explicitly on the rhs as type constraints;
  3788 
  3789 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3790 names rather than an ML expression;
  3791 
  3792 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3793 supplied later.  Program schemes can be defined, such as
  3794     "While B C s = (if B s then While B C (C s) else s)"
  3795 where the well-founded relation can be chosen after B and C have been given.
  3796 
  3797 * HOL/List: the constructors of type list are now Nil and Cons;
  3798 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3799 course, ML tools referring to List.list.op # etc. have to be adapted;
  3800 
  3801 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3802 disabled by default; run isabelle with option -m HOL to get back to
  3803 the original Gordon/HOL-style output;
  3804 
  3805 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3806 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3807 
  3808 * HOL basic syntax simplified (more orthogonal): all variants of
  3809 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3810 Eps operator is provided as well: "SOME x. P[x]";
  3811 
  3812 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3813 
  3814 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3815 thus available for user theories;
  3816 
  3817 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3818 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3819 time;
  3820 
  3821 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3822 several times and then mp;
  3823 
  3824 
  3825 *** LK ***
  3826 
  3827 * the notation <<...>> is now available as a notation for sequences of
  3828 formulas;
  3829 
  3830 * the simplifier is now installed
  3831 
  3832 * the axiom system has been generalized (thanks to Soren Heilmann)
  3833 
  3834 * the classical reasoner now has a default rule database
  3835 
  3836 
  3837 *** ZF ***
  3838 
  3839 * new primrec section allows primitive recursive functions to be given
  3840 directly (as in HOL) over datatypes and the natural numbers;
  3841 
  3842 * new tactics induct_tac and exhaust_tac for induction (or case
  3843 analysis) over datatypes and the natural numbers;
  3844 
  3845 * the datatype declaration of type T now defines the recursor T_rec;
  3846 
  3847 * simplification automatically does freeness reasoning for datatype
  3848 constructors;
  3849 
  3850 * automatic type-inference, with AddTCs command to insert new
  3851 type-checking rules;
  3852 
  3853 * datatype introduction rules are now added as Safe Introduction rules
  3854 to the claset;
  3855 
  3856 * the syntax "if P then x else y" is now available in addition to
  3857 if(P,x,y);
  3858 
  3859 
  3860 *** Internal programming interfaces ***
  3861 
  3862 * tuned simplifier trace output; new flag debug_simp;
  3863 
  3864 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3865 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3866 
  3867 * AxClass.axclass_tac lost the theory argument;
  3868 
  3869 * tuned current_goals_markers semantics: begin / end goal avoids
  3870 printing empty lines;
  3871 
  3872 * removed prs and prs_fn hook, which was broken because it did not
  3873 include \n in its semantics, forcing writeln to add one
  3874 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3875 string -> unit if you really want to output text without newline;
  3876 
  3877 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3878 plain output, interface builders may have to enable 'isabelle_font'
  3879 mode to get Isabelle font glyphs as before;
  3880 
  3881 * refined token_translation interface; INCOMPATIBILITY: output length
  3882 now of type real instead of int;
  3883 
  3884 * theory loader actions may be traced via new ThyInfo.add_hook
  3885 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3886 your own database of information attached to *whole* theories -- as
  3887 opposed to intra-theory data slots offered via TheoryDataFun;
  3888 
  3889 * proper handling of dangling sort hypotheses (at last!);
  3890 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3891 extra sort hypotheses that can be witnessed from the type signature;
  3892 the force_strip_shyps flag is gone, any remaining shyps are simply
  3893 left in the theorem (with a warning issued by strip_shyps_warning);
  3894 
  3895 
  3896 
  3897 New in Isabelle98-1 (October 1998)
  3898 ----------------------------------
  3899 
  3900 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3901 
  3902 * several changes of automated proof tools;
  3903 
  3904 * HOL: major changes to the inductive and datatype packages, including
  3905 some minor incompatibilities of theory syntax;
  3906 
  3907 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3908 called `inj_on';
  3909 
  3910 * HOL: removed duplicate thms in Arith:
  3911   less_imp_add_less  should be replaced by  trans_less_add1
  3912   le_imp_add_le      should be replaced by  trans_le_add1
  3913 
  3914 * HOL: unary minus is now overloaded (new type constraints may be
  3915 required);
  3916 
  3917 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3918 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3919 now taken as an integer constant.
  3920 
  3921 * Pure: ML function 'theory_of' renamed to 'theory';
  3922 
  3923 
  3924 *** Proof tools ***
  3925 
  3926 * Simplifier:
  3927   1. Asm_full_simp_tac is now more aggressive.
  3928      1. It will sometimes reorient premises if that increases their power to
  3929         simplify.
  3930      2. It does no longer proceed strictly from left to right but may also
  3931         rotate premises to achieve further simplification.
  3932      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3933      old Asm_full_simp_tac in that it does not rotate premises.
  3934   2. The simplifier now knows a little bit about nat-arithmetic.
  3935 
  3936 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3937 allows for selected deletion of wrappers, by introduction of names for
  3938 wrapper functionals.  This implies that addbefore, addSbefore,
  3939 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3940 and that adding two tactics with the same name overwrites the first
  3941 one (emitting a warning).
  3942   type wrapper = (int -> tactic) -> (int -> tactic)
  3943   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3944   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3945   delWrapper, delSWrapper: claset *  string            -> claset
  3946   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3947 
  3948 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3949 semantics; addbefore now affects only the unsafe part of step_tac
  3950 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3951 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3952 by Force_tac;
  3953 
  3954 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3955 compWrapper; added safe wrapper (and access functions for it);
  3956 
  3957 * HOL/split_all_tac is now much faster and fails if there is nothing
  3958 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3959 and the names of the automatically generated variables have changed.
  3960 split_all_tac has moved within claset() from unsafe wrappers to safe
  3961 wrappers, which means that !!-bound variables are split much more
  3962 aggressively, and safe_tac and clarify_tac now split such variables.
  3963 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3964 Note: the same holds for record_split_tac, which does the job of
  3965 split_all_tac for record fields.
  3966 
  3967 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3968 permanently to the default simpset using Addsplits just like
  3969 Addsimps. They can be removed via Delsplits just like
  3970 Delsimps. Lower-case versions are also available.
  3971 
  3972 * HOL/Simplifier: The rule split_if is now part of the default
  3973 simpset. This means that the simplifier will eliminate all occurrences
  3974 of if-then-else in the conclusion of a goal. To prevent this, you can
  3975 either remove split_if completely from the default simpset by
  3976 `Delsplits [split_if]' or remove it in a specific call of the
  3977 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3978 other case splitting rules to/from the default simpset: every datatype
  3979 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3980 t is the name of the datatype).
  3981 
  3982 * Classical reasoner / Simplifier combination: new force_tac (and
  3983 derivatives Force_tac, force) combines rewriting and classical
  3984 reasoning (and whatever other tools) similarly to auto_tac, but is
  3985 aimed to solve the given subgoal completely.
  3986 
  3987 
  3988 *** General ***
  3989 
  3990 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3991 and `goalw': the theory is no longer needed as an explicit argument -
  3992 the current theory context is used; assumptions are no longer returned
  3993 at the ML-level unless one of them starts with ==> or !!; it is
  3994 recommended to convert to these new commands using isatool fixgoal
  3995 (backup your sources first!);
  3996 
  3997 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3998 the current theory context, and 'theory' to lookup stored theories;
  3999 
  4000 * new theory section 'locale' for declaring constants, assumptions and
  4001 definitions that have local scope;
  4002 
  4003 * new theory section 'nonterminals' for purely syntactic types;
  4004 
  4005 * new theory section 'setup' for generic ML setup functions
  4006 (e.g. package initialization);
  4007 
  4008 * the distribution now includes Isabelle icons: see
  4009 lib/logo/isabelle-{small,tiny}.xpm;
  4010 
  4011 * isatool install - install binaries with absolute references to
  4012 ISABELLE_HOME/bin;
  4013 
  4014 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4015 
  4016 * print mode 'emacs' reserved for Isamode;
  4017 
  4018 * support multiple print (ast) translations per constant name;
  4019 
  4020 * theorems involving oracles are now printed with a suffixed [!];
  4021 
  4022 
  4023 *** HOL ***
  4024 
  4025 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4026 
  4027 * HOL/inductive package reorganized and improved: now supports mutual
  4028 definitions such as
  4029 
  4030   inductive EVEN ODD
  4031     intrs
  4032       null "0 : EVEN"
  4033       oddI "n : EVEN ==> Suc n : ODD"
  4034       evenI "n : ODD ==> Suc n : EVEN"
  4035 
  4036 new theorem list "elims" contains an elimination rule for each of the
  4037 recursive sets; inductive definitions now handle disjunctive premises
  4038 correctly (also ZF);
  4039 
  4040 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4041 "mutual_induct" no longer exists - the induction rule is always
  4042 contained in "induct";
  4043 
  4044 
  4045 * HOL/datatype package re-implemented and greatly improved: now
  4046 supports mutually recursive datatypes such as
  4047 
  4048   datatype
  4049     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4050             | SUM ('a aexp) ('a aexp)
  4051             | DIFF ('a aexp) ('a aexp)
  4052             | NUM 'a
  4053   and
  4054     'a bexp = LESS ('a aexp) ('a aexp)
  4055             | AND ('a bexp) ('a bexp)
  4056             | OR ('a bexp) ('a bexp)
  4057 
  4058 as well as indirectly recursive datatypes such as
  4059 
  4060   datatype
  4061     ('a, 'b) term = Var 'a
  4062                   | App 'b ((('a, 'b) term) list)
  4063 
  4064 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4065 induction on mutually / indirectly recursive datatypes.
  4066 
  4067 Primrec equations are now stored in theory and can be accessed via
  4068 <function_name>.simps.
  4069 
  4070 INCOMPATIBILITIES:
  4071 
  4072   - Theories using datatypes must now have theory Datatype as an
  4073     ancestor.
  4074   - The specific <typename>.induct_tac no longer exists - use the
  4075     generic induct_tac instead.
  4076   - natE has been renamed to nat.exhaust - use exhaust_tac
  4077     instead of res_inst_tac ... natE. Note that the variable
  4078     names in nat.exhaust differ from the names in natE, this
  4079     may cause some "fragile" proofs to fail.
  4080   - The theorems split_<typename>_case and split_<typename>_case_asm
  4081     have been renamed to <typename>.split and <typename>.split_asm.
  4082   - Since default sorts of type variables are now handled correctly,
  4083     some datatype definitions may have to be annotated with explicit
  4084     sort constraints.
  4085   - Primrec definitions no longer require function name and type
  4086     of recursive argument.
  4087 
  4088 Consider using isatool fixdatatype to adapt your theories and proof
  4089 scripts to the new package (backup your sources first!).
  4090 
  4091 
  4092 * HOL/record package: considerably improved implementation; now
  4093 includes concrete syntax for record types, terms, updates; theorems
  4094 for surjective pairing and splitting !!-bound record variables; proof
  4095 support is as follows:
  4096 
  4097   1) standard conversions (selectors or updates applied to record
  4098 constructor terms) are part of the standard simpset;
  4099 
  4100   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4101 made part of standard simpset and claset via addIffs;
  4102 
  4103   3) a tactic for record field splitting (record_split_tac) is part of
  4104 the standard claset (addSWrapper);
  4105 
  4106 To get a better idea about these rules you may retrieve them via
  4107 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4108 the name of your record type.
  4109 
  4110 The split tactic 3) conceptually simplifies by the following rule:
  4111 
  4112   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4113 
  4114 Thus any record variable that is bound by meta-all will automatically
  4115 blow up into some record constructor term, consequently the
  4116 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4117 solve record problems automatically.
  4118 
  4119 
  4120 * reorganized the main HOL image: HOL/Integ and String loaded by
  4121 default; theory Main includes everything;
  4122 
  4123 * automatic simplification of integer sums and comparisons, using cancellation;
  4124 
  4125 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4126 
  4127 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4128 
  4129 * many new identities for unions, intersections, set difference, etc.;
  4130 
  4131 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4132 called split_if, split_split, split_sum_case and split_nat_case (to go
  4133 with add/delsplits);
  4134 
  4135 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4136 (?x::unit) = (); this is made part of the default simpset, which COULD
  4137 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4138 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4139 unit_abs_eta_conv is added in order to counter the effect of
  4140 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4141 %u.f();
  4142 
  4143 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4144 makes more sense);
  4145 
  4146 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4147   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4148   disjointness reasoning but breaking a few old proofs.
  4149 
  4150 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4151 to 'converse' from 'inverse' (for compatibility with ZF and some
  4152 literature);
  4153 
  4154 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4155 the well-founded relation;
  4156 
  4157 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4158     Compl A.  The "Compl" syntax remains available as input syntax for this
  4159     release ONLY.
  4160 
  4161 * HOL/Update: new theory of function updates:
  4162     f(a:=b) == %x. if x=a then b else f x
  4163 may also be iterated as in f(a:=b,c:=d,...);
  4164 
  4165 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4166 
  4167 * HOL/List:
  4168   - new function list_update written xs[i:=v] that updates the i-th
  4169     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4170   - new function `upt' written [i..j(] which generates the list
  4171     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4172     bound write [i..j], which is a shorthand for [i..j+1(].
  4173   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4174 
  4175 * HOL/Arith:
  4176   - removed 'pred' (predecessor) function;
  4177   - generalized some theorems about n-1;
  4178   - many new laws about "div" and "mod";
  4179   - new laws about greatest common divisors (see theory ex/Primes);
  4180 
  4181 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4182 instead of "inverse";
  4183 
  4184 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4185   of the multiset ordering;
  4186 
  4187 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4188   (not included by default);
  4189 
  4190 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4191 
  4192 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4193   programs, i.e. different program variables may have different types.
  4194 
  4195 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4196   [previously, this check worked only if the rewrite rule was unconditional]
  4197   Now rew can involve either definitions or equalities (either == or =).
  4198 
  4199 
  4200 *** ZF ***
  4201 
  4202 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4203   only the theorems proved on ZF.ML;
  4204 
  4205 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4206   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4207   disjointness reasoning but breaking a few old proofs.
  4208 
  4209 * ZF/Update: new theory of function updates
  4210     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4211   may also be iterated as in f(a:=b,c:=d,...);
  4212 
  4213 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4214 
  4215 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4216   [previously, this check worked only if the rewrite rule was unconditional]
  4217   Now rew can involve either definitions or equalities (either == or =).
  4218 
  4219 * case_tac provided for compatibility with HOL
  4220     (like the old excluded_middle_tac, but with subgoals swapped)
  4221 
  4222 
  4223 *** Internal programming interfaces ***
  4224 
  4225 * Pure: several new basic modules made available for general use, see
  4226 also src/Pure/README;
  4227 
  4228 * improved the theory data mechanism to support encapsulation (data
  4229 kind name replaced by private Object.kind, acting as authorization
  4230 key); new type-safe user interface via functor TheoryDataFun; generic
  4231 print_data function becomes basically useless;
  4232 
  4233 * removed global_names compatibility flag -- all theory declarations
  4234 are qualified by default;
  4235 
  4236 * module Pure/Syntax now offers quote / antiquote translation
  4237 functions (useful for Hoare logic etc. with implicit dependencies);
  4238 see HOL/ex/Antiquote for an example use;
  4239 
  4240 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4241 cterm -> thm;
  4242 
  4243 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4244 subgoal;
  4245 
  4246 * Display.print_goals function moved to Locale.print_goals;
  4247 
  4248 * standard print function for goals supports current_goals_markers
  4249 variable for marking begin of proof, end of proof, start of goal; the
  4250 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4251 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4252 for example;
  4253 
  4254 
  4255 
  4256 New in Isabelle98 (January 1998)
  4257 --------------------------------
  4258 
  4259 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4260 
  4261 * changed lexical syntax of terms / types: dots made part of long
  4262 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4263 
  4264 * simpset (and claset) reference variable replaced by functions
  4265 simpset / simpset_ref;
  4266 
  4267 * no longer supports theory aliases (via merge) and non-trivial
  4268 implicit merge of thms' signatures;
  4269 
  4270 * most internal names of constants changed due to qualified names;
  4271 
  4272 * changed Pure/Sequence interface (see Pure/seq.ML);
  4273 
  4274 
  4275 *** General Changes ***
  4276 
  4277 * hierachically structured name spaces (for consts, types, axms, thms
  4278 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4279 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4280 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4281 long_names for fully qualified output names; NOTE: ML programs
  4282 (special tactics, packages etc.) referring to internal names may have
  4283 to be adapted to cope with fully qualified names; in case of severe
  4284 backward campatibility problems try setting 'global_names' at compile
  4285 time to have enrything declared within a flat name space; one may also
  4286 fine tune name declarations in theories via the 'global' and 'local'
  4287 section;
  4288 
  4289 * reimplemented the implicit simpset and claset using the new anytype
  4290 data filed in signatures; references simpset:simpset ref etc. are
  4291 replaced by functions simpset:unit->simpset and
  4292 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4293 to patch your ML files accordingly;
  4294 
  4295 * HTML output now includes theory graph data for display with Java
  4296 applet or isatool browser; data generated automatically via isatool
  4297 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4298 
  4299 * defs may now be conditional; improved rewrite_goals_tac to handle
  4300 conditional equations;
  4301 
  4302 * defs now admits additional type arguments, using TYPE('a) syntax;
  4303 
  4304 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4305 creates a new theory node; implicit merge of thms' signatures is
  4306 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4307 transfer:theory->thm->thm in (rare) cases;
  4308 
  4309 * improved handling of draft signatures / theories; draft thms (and
  4310 ctyps, cterms) are automatically promoted to real ones;
  4311 
  4312 * slightly changed interfaces for oracles: admit many per theory, named
  4313 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4314 
  4315 * print_goals: optional output of const types (set show_consts and
  4316 show_types);
  4317 
  4318 * improved output of warnings (###) and errors (***);
  4319 
  4320 * subgoal_tac displays a warning if the new subgoal has type variables;
  4321 
  4322 * removed old README and Makefiles;
  4323 
  4324 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4325 
  4326 * removed obsolete init_pps and init_database;
  4327 
  4328 * deleted the obsolete tactical STATE, which was declared by
  4329     fun STATE tacfun st = tacfun st st;
  4330 
  4331 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4332 (which abbreviates $HOME);
  4333 
  4334 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4335 use isatool fixseq to adapt your ML programs (this works for fully
  4336 qualified references to the Sequence structure only!);
  4337 
  4338 * use_thy no longer requires writable current directory; it always
  4339 reloads .ML *and* .thy file, if either one is out of date;
  4340 
  4341 
  4342 *** Classical Reasoner ***
  4343 
  4344 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4345 tactics that use classical reasoning to simplify a subgoal without
  4346 splitting it into several subgoals;
  4347 
  4348 * Safe_tac: like safe_tac but uses the default claset;
  4349 
  4350 
  4351 *** Simplifier ***
  4352 
  4353 * added simplification meta rules:
  4354     (asm_)(full_)simplify: simpset -> thm -> thm;
  4355 
  4356 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4357 logics (again);
  4358 
  4359 * added prems argument to simplification procedures;
  4360 
  4361 * HOL, FOL, ZF: added infix function `addsplits':
  4362   instead of `<simpset> setloop (split_tac <thms>)'
  4363   you can simply write `<simpset> addsplits <thms>'
  4364 
  4365 
  4366 *** Syntax ***
  4367 
  4368 * TYPE('a) syntax for type reflection terms;
  4369 
  4370 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4371 
  4372 * pretty printer: changed order of mixfix annotation preference (again!);
  4373 
  4374 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4375 
  4376 
  4377 *** HOL ***
  4378 
  4379 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4380   with `addloop' of the simplifier to faciliate case splitting in premises.
  4381 
  4382 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4383 
  4384 * HOL/Auth: new protocol proofs including some for the Internet
  4385   protocol TLS;
  4386 
  4387 * HOL/Map: new theory of `maps' a la VDM;
  4388 
  4389 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4390 cancelling out common nat summands from =, <, <= (in)equalities, or
  4391 differences; simplification procedures nat_cancel_factor for
  4392 cancelling common factor from =, <, <= (in)equalities over natural
  4393 sums; nat_cancel contains both kinds of procedures, it is installed by
  4394 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4395 
  4396 * HOL/simplifier: terms of the form
  4397   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4398   are rewritten to
  4399   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4400   and those of the form
  4401   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4402   are rewritten to
  4403   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4404 
  4405 * HOL/datatype
  4406   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4407 
  4408   P(t_case f1 ... fn x) =
  4409      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4410         ...
  4411        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4412      )
  4413 
  4414   and a theorem `split_t_case_asm' of the form
  4415 
  4416   P(t_case f1 ... fn x) =
  4417     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4418         ...
  4419        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4420      )
  4421   which can be added to a simpset via `addsplits'. The existing theorems
  4422   expand_list_case and expand_option_case have been renamed to
  4423   split_list_case and split_option_case.
  4424 
  4425 * HOL/Arithmetic:
  4426   - `pred n' is automatically converted to `n-1'.
  4427     Users are strongly encouraged not to use `pred' any longer,
  4428     because it will disappear altogether at some point.
  4429   - Users are strongly encouraged to write "0 < n" rather than
  4430     "n ~= 0". Theorems and proof tools have been modified towards this
  4431     `standard'.
  4432 
  4433 * HOL/Lists:
  4434   the function "set_of_list" has been renamed "set" (and its theorems too);
  4435   the function "nth" now takes its arguments in the reverse order and
  4436   has acquired the infix notation "!" as in "xs!n".
  4437 
  4438 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4439 
  4440 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4441   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4442 
  4443 * HOL/record: extensible records with schematic structural subtyping
  4444 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4445 still lacks various theorems and concrete record syntax;
  4446 
  4447 
  4448 *** HOLCF ***
  4449 
  4450 * removed "axioms" and "generated by" sections;
  4451 
  4452 * replaced "ops" section by extended "consts" section, which is capable of
  4453   handling the continuous function space "->" directly;
  4454 
  4455 * domain package:
  4456   . proves theorems immediately and stores them in the theory,
  4457   . creates hierachical name space,
  4458   . now uses normal mixfix annotations (instead of cinfix...),
  4459   . minor changes to some names and values (for consistency),
  4460   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4461   . separator between mutual domain defs: changed "," to "and",
  4462   . improved handling of sort constraints;  now they have to
  4463     appear on the left-hand side of the equations only;
  4464 
  4465 * fixed LAM <x,y,zs>.b syntax;
  4466 
  4467 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4468 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4469 
  4470 
  4471 *** FOL and ZF ***
  4472 
  4473 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4474   with `addloop' of the simplifier to faciliate case splitting in premises.
  4475 
  4476 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4477 in HOL, they strip ALL and --> from proved theorems;
  4478 
  4479 
  4480 
  4481 New in Isabelle94-8 (May 1997)
  4482 ------------------------------
  4483 
  4484 *** General Changes ***
  4485 
  4486 * new utilities to build / run / maintain Isabelle etc. (in parts
  4487 still somewhat experimental); old Makefiles etc. still functional;
  4488 
  4489 * new 'Isabelle System Manual';
  4490 
  4491 * INSTALL text, together with ./configure and ./build scripts;
  4492 
  4493 * reimplemented type inference for greater efficiency, better error
  4494 messages and clean internal interface;
  4495 
  4496 * prlim command for dealing with lots of subgoals (an easier way of
  4497 setting goals_limit);
  4498 
  4499 
  4500 *** Syntax ***
  4501 
  4502 * supports alternative (named) syntax tables (parser and pretty
  4503 printer); internal interface is provided by add_modesyntax(_i);
  4504 
  4505 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4506 be used in conjunction with the Isabelle symbol font; uses the
  4507 "symbols" syntax table;
  4508 
  4509 * added token_translation interface (may translate name tokens in
  4510 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4511 the current print_mode); IMPORTANT: user print translation functions
  4512 are responsible for marking newly introduced bounds
  4513 (Syntax.mark_boundT);
  4514 
  4515 * token translations for modes "xterm" and "xterm_color" that display
  4516 names in bold, underline etc. or colors (which requires a color
  4517 version of xterm);
  4518 
  4519 * infixes may now be declared with names independent of their syntax;
  4520 
  4521 * added typed_print_translation (like print_translation, but may
  4522 access type of constant);
  4523 
  4524 
  4525 *** Classical Reasoner ***
  4526 
  4527 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4528 some limitations.  Blast_tac...
  4529   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4530   + ignores elimination rules that don't have the correct format
  4531         (the conclusion MUST be a formula variable)
  4532   + ignores types, which can make HOL proofs fail
  4533   + rules must not require higher-order unification, e.g. apply_type in ZF
  4534     [message "Function Var's argument not a bound variable" relates to this]
  4535   + its proof strategy is more general but can actually be slower
  4536 
  4537 * substitution with equality assumptions no longer permutes other
  4538 assumptions;
  4539 
  4540 * minor changes in semantics of addafter (now called addaltern); renamed
  4541 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4542 (and access functions for it);
  4543 
  4544 * improved combination of classical reasoner and simplifier:
  4545   + functions for handling clasimpsets
  4546   + improvement of addss: now the simplifier is called _after_ the
  4547     safe steps.
  4548   + safe variant of addss called addSss: uses safe simplifications
  4549     _during_ the safe steps. It is more complete as it allows multiple
  4550     instantiations of unknowns (e.g. with slow_tac).
  4551 
  4552 *** Simplifier ***
  4553 
  4554 * added interface for simplification procedures (functions that
  4555 produce *proven* rewrite rules on the fly, depending on current
  4556 redex);
  4557 
  4558 * ordering on terms as parameter (used for ordered rewriting);
  4559 
  4560 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4561 
  4562 * the solver is now split into a safe and an unsafe part.
  4563 This should be invisible for the normal user, except that the
  4564 functions setsolver and addsolver have been renamed to setSolver and
  4565 addSolver; added safe_asm_full_simp_tac;
  4566 
  4567 
  4568 *** HOL ***
  4569 
  4570 * a generic induction tactic `induct_tac' which works for all datatypes and
  4571 also for type `nat';
  4572 
  4573 * a generic case distinction tactic `exhaust_tac' which works for all
  4574 datatypes and also for type `nat';
  4575 
  4576 * each datatype comes with a function `size';
  4577 
  4578 * patterns in case expressions allow tuple patterns as arguments to
  4579 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4580 
  4581 * primrec now also works with type nat;
  4582 
  4583 * recdef: a new declaration form, allows general recursive functions to be
  4584 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4585 
  4586 * the constant for negation has been renamed from "not" to "Not" to
  4587 harmonize with FOL, ZF, LK, etc.;
  4588 
  4589 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4590 infinite lists;
  4591 
  4592 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4593 
  4594 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4595 problems in commutative rings, using axiomatic type classes for + and *;
  4596 
  4597 * more examples in HOL/MiniML and HOL/Auth;
  4598 
  4599 * more default rewrite rules for quantifiers, union/intersection;
  4600 
  4601 * a new constant `arbitrary == @x.False';
  4602 
  4603 * HOLCF/IOA replaces old HOL/IOA;
  4604 
  4605 * HOLCF changes: derived all rules and arities
  4606   + axiomatic type classes instead of classes
  4607   + typedef instead of faking type definitions
  4608   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4609   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4610   + eliminated the types void, one, tr
  4611   + use unit lift and bool lift (with translations) instead of one and tr
  4612   + eliminated blift from Lift3.thy (use Def instead of blift)
  4613   all eliminated rules are derived as theorems --> no visible changes ;
  4614 
  4615 
  4616 *** ZF ***
  4617 
  4618 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4619 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4620 as ZF_cs addSIs [equalityI];
  4621 
  4622 
  4623 
  4624 New in Isabelle94-7 (November 96)
  4625 ---------------------------------
  4626 
  4627 * allowing negative levels (as offsets) in prlev and choplev;
  4628 
  4629 * super-linear speedup for large simplifications;
  4630 
  4631 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4632 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4633 FAIL); can suppress it using the command Delsimps (ex_simps @
  4634 all_simps); De Morgan laws are also now included, by default;
  4635 
  4636 * improved printing of ==>  :  ~:
  4637 
  4638 * new object-logic "Sequents" adds linear logic, while replacing LK
  4639 and Modal (thanks to Sara Kalvala);
  4640 
  4641 * HOL/Auth: correctness proofs for authentication protocols;
  4642 
  4643 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4644 examples on HOL/Auth);
  4645 
  4646 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4647 the rewriter and classical reasoner simultaneously;
  4648 
  4649 * function uresult no longer returns theorems in "standard" format;
  4650 regain previous version by: val uresult = standard o uresult;
  4651 
  4652 
  4653 
  4654 New in Isabelle94-6
  4655 -------------------
  4656 
  4657 * oracles -- these establish an interface between Isabelle and trusted
  4658 external reasoners, which may deliver results as theorems;
  4659 
  4660 * proof objects (in particular record all uses of oracles);
  4661 
  4662 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4663 
  4664 * "constdefs" section in theory files;
  4665 
  4666 * "primrec" section (HOL) no longer requires names;
  4667 
  4668 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4669 
  4670 
  4671 
  4672 New in Isabelle94-5
  4673 -------------------
  4674 
  4675 * reduced space requirements;
  4676 
  4677 * automatic HTML generation from theories;
  4678 
  4679 * theory files no longer require "..." (quotes) around most types;
  4680 
  4681 * new examples, including two proofs of the Church-Rosser theorem;
  4682 
  4683 * non-curried (1994) version of HOL is no longer distributed;
  4684 
  4685 
  4686 
  4687 New in Isabelle94-4
  4688 -------------------
  4689 
  4690 * greatly reduced space requirements;
  4691 
  4692 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4693 
  4694 * searchable theorem database (see the section "Retrieving theorems" on
  4695 page 8 of the Reference Manual);
  4696 
  4697 * new examples, including Grabczewski's monumental case study of the
  4698 Axiom of Choice;
  4699 
  4700 * The previous version of HOL renamed to Old_HOL;
  4701 
  4702 * The new version of HOL (previously called CHOL) uses a curried syntax
  4703 for functions.  Application looks like f a b instead of f(a,b);
  4704 
  4705 * Mutually recursive inductive definitions finally work in HOL;
  4706 
  4707 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4708 translates to the operator "split";
  4709 
  4710 
  4711 
  4712 New in Isabelle94-3
  4713 -------------------
  4714 
  4715 * new infix operator, addss, allowing the classical reasoner to
  4716 perform simplification at each step of its search.  Example:
  4717         fast_tac (cs addss ss)
  4718 
  4719 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4720 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4721 look like (a,b) instead of <a,b>;
  4722 
  4723 * PLEASE NOTE: CHOL will eventually replace HOL!
  4724 
  4725 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4726 It translates to the operator "split".  A new theory of integers is available;
  4727 
  4728 * In ZF, integer numerals now denote two's-complement binary integers.
  4729 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4730 
  4731 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4732 of the Axiom of Choice;
  4733 
  4734 
  4735 
  4736 New in Isabelle94-2
  4737 -------------------
  4738 
  4739 * Significantly faster resolution;
  4740 
  4741 * the different sections in a .thy file can now be mixed and repeated
  4742 freely;
  4743 
  4744 * Database of theorems for FOL, HOL and ZF.  New
  4745 commands including qed, qed_goal and bind_thm store theorems in the database.
  4746 
  4747 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4748 a given theory (thms_of), or find out what theory a theorem was proved in
  4749 (theory_of_thm);
  4750 
  4751 * Bugs fixed in the inductive definition and datatype packages;
  4752 
  4753 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4754 and HOL_dup_cs obsolete;
  4755 
  4756 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4757 have been removed;
  4758 
  4759 * Simpler definition of function space in ZF;
  4760 
  4761 * new results about cardinal and ordinal arithmetic in ZF;
  4762 
  4763 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4764 types;
  4765 
  4766 
  4767 $Id$