NEWS
author nipkow
Fri May 25 18:11:25 2007 +0200 (2007-05-25)
changeset 23103 b00e7ce9dcdc
parent 23102 559709b43104
child 23104 0a47a5681704
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 * Library/List_Comprehension.thy provides Haskell-like input syntax for list
   554   comprehensions.
   555 
   556 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   557     when generating code.
   558 
   559 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   560     when generating code.
   561 
   562 * Library/Commutative_Ring.thy: switched from recdef to function package;
   563     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   564 
   565 * Some steps towards more uniform lattice theory development in HOL.
   566 
   567     constants "meet" and "join" now named "inf" and "sup"
   568     constant "Meet" now named "Inf"
   569 
   570     classes "meet_semilorder" and "join_semilorder" now named
   571       "lower_semilattice" and "upper_semilattice"
   572     class "lorder" now named "lattice"
   573     class "comp_lat" now named "complete_lattice"
   574 
   575     Instantiation of lattice classes allows explicit definitions
   576     for "inf" and "sup" operations.
   577 
   578   INCOMPATIBILITY. Theorem renames:
   579 
   580     meet_left_le            ~> inf_le1
   581     meet_right_le           ~> inf_le2
   582     join_left_le            ~> sup_ge1
   583     join_right_le           ~> sup_ge2
   584     meet_join_le            ~> inf_sup_ord
   585     le_meetI                ~> le_infI
   586     join_leI                ~> le_supI
   587     le_meet                 ~> le_inf_iff
   588     le_join                 ~> ge_sup_conv
   589     meet_idempotent         ~> inf_idem
   590     join_idempotent         ~> sup_idem
   591     meet_comm               ~> inf_commute
   592     join_comm               ~> sup_commute
   593     meet_leI1               ~> le_infI1
   594     meet_leI2               ~> le_infI2
   595     le_joinI1               ~> le_supI1
   596     le_joinI2               ~> le_supI2
   597     meet_assoc              ~> inf_assoc
   598     join_assoc              ~> sup_assoc
   599     meet_left_comm          ~> inf_left_commute
   600     meet_left_idempotent    ~> inf_left_idem
   601     join_left_comm          ~> sup_left_commute
   602     join_left_idempotent    ~> sup_left_idem
   603     meet_aci                ~> inf_aci
   604     join_aci                ~> sup_aci
   605     le_def_meet             ~> le_iff_inf
   606     le_def_join             ~> le_iff_sup
   607     join_absorp2            ~> sup_absorb2
   608     join_absorp1            ~> sup_absorb1
   609     meet_absorp1            ~> inf_absorb1
   610     meet_absorp2            ~> inf_absorb2
   611     meet_join_absorp        ~> inf_sup_absorb
   612     join_meet_absorp        ~> sup_inf_absorb
   613     distrib_join_le         ~> distrib_sup_le
   614     distrib_meet_le         ~> distrib_inf_le
   615 
   616     add_meet_distrib_left   ~> add_inf_distrib_left
   617     add_join_distrib_left   ~> add_sup_distrib_left
   618     is_join_neg_meet        ~> is_join_neg_inf
   619     is_meet_neg_join        ~> is_meet_neg_sup
   620     add_meet_distrib_right  ~> add_inf_distrib_right
   621     add_join_distrib_right  ~> add_sup_distrib_right
   622     add_meet_join_distribs  ~> add_sup_inf_distribs
   623     join_eq_neg_meet        ~> sup_eq_neg_inf
   624     meet_eq_neg_join        ~> inf_eq_neg_sup
   625     add_eq_meet_join        ~> add_eq_inf_sup
   626     meet_0_imp_0            ~> inf_0_imp_0
   627     join_0_imp_0            ~> sup_0_imp_0
   628     meet_0_eq_0             ~> inf_0_eq_0
   629     join_0_eq_0             ~> sup_0_eq_0
   630     neg_meet_eq_join        ~> neg_inf_eq_sup
   631     neg_join_eq_meet        ~> neg_sup_eq_inf
   632     join_eq_if              ~> sup_eq_if
   633 
   634     mono_meet               ~> mono_inf
   635     mono_join               ~> mono_sup
   636     meet_bool_eq            ~> inf_bool_eq
   637     join_bool_eq            ~> sup_bool_eq
   638     meet_fun_eq             ~> inf_fun_eq
   639     join_fun_eq             ~> sup_fun_eq
   640     meet_set_eq             ~> inf_set_eq
   641     join_set_eq             ~> sup_set_eq
   642     meet1_iff               ~> inf1_iff
   643     meet2_iff               ~> inf2_iff
   644     meet1I                  ~> inf1I
   645     meet2I                  ~> inf2I
   646     meet1D1                 ~> inf1D1
   647     meet2D1                 ~> inf2D1
   648     meet1D2                 ~> inf1D2
   649     meet2D2                 ~> inf2D2
   650     meet1E                  ~> inf1E
   651     meet2E                  ~> inf2E
   652     join1_iff               ~> sup1_iff
   653     join2_iff               ~> sup2_iff
   654     join1I1                 ~> sup1I1
   655     join2I1                 ~> sup2I1
   656     join1I1                 ~> sup1I1
   657     join2I2                 ~> sup1I2
   658     join1CI                 ~> sup1CI
   659     join2CI                 ~> sup2CI
   660     join1E                  ~> sup1E
   661     join2E                  ~> sup2E
   662 
   663     is_meet_Meet            ~> is_meet_Inf
   664     Meet_bool_def           ~> Inf_bool_def
   665     Meet_fun_def            ~> Inf_fun_def
   666     Meet_greatest           ~> Inf_greatest
   667     Meet_lower              ~> Inf_lower
   668     Meet_set_def            ~> Inf_set_def
   669 
   670     listsp_meetI            ~> listsp_infI
   671     listsp_meet_eq          ~> listsp_inf_eq
   672 
   673     meet_min                ~> inf_min
   674     join_max                ~> sup_max
   675 
   676 * Classes "order" and "linorder": facts "refl", "trans" and
   677 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   678 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   679 
   680 * Classes "order" and "linorder": 
   681 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   682 proofs changed.
   683 
   684 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   685 INCOMPATIBILITY.
   686 
   687 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   688 INCOMPATIBILITY.
   689 
   690 * Added syntactic class "size"; overloaded constant "size" now has
   691 type "'a::size ==> bool"
   692 
   693 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   694 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   695 
   696 * Added method "lexicographic_order" automatically synthesizes
   697 termination relations as lexicographic combinations of size measures
   698 -- 'function' package.
   699 
   700 * HOL/records: generalised field-update to take a function on the
   701 field rather than the new value: r(|A := x|) is translated to A_update
   702 (K x) r The K-combinator that is internally used is called K_record.
   703 INCOMPATIBILITY: Usage of the plain update functions has to be
   704 adapted.
   705  
   706 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   707 0 * x = 0, which are required for a semiring.  Richer structures do
   708 not inherit from semiring_0 anymore, because this property is a
   709 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   710 semiring_0, there is more to prove, but this is mostly trivial.
   711 
   712 * axclass "recpower" was generalized to arbitrary monoids, not just
   713 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   714 commutativity or a semiring property, add the corresponding classes.
   715 
   716 * Unified locale partial_order with class definition (cf. theory
   717 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   718 
   719 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   720 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   721 Isar level, use abbreviations instead.
   722 
   723 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   724 rarely occuring name references (e.g. ``List.op mem.simps'') require
   725 renaming (e.g. ``List.memberl.simps'').
   726 
   727 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   728 INCOMPATIBILITY.
   729 
   730 * Added theory Code_Generator providing class 'eq', allowing for code
   731 generation with polymorphic equality.
   732 
   733 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   734 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   735 significant changes for setting up numeral syntax for types:
   736 
   737   - new constants Numeral.pred and Numeral.succ instead
   738       of former Numeral.bin_pred and Numeral.bin_succ.
   739   - Use integer operations instead of bin_add, bin_mult and so on.
   740   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   741   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   742 
   743 See HOL/Integ/IntArith.thy for an example setup.
   744 
   745 * New top level command 'normal_form' computes the normal form of a
   746 term that may contain free variables. For example ``normal_form
   747 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   748 suitable for heavy-duty computations because the functions are
   749 compiled to ML first.
   750 
   751 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   752 25 like -->); output depends on the "iff" print_mode, the default is
   753 "A = B" (with priority 50).
   754 
   755 * Renamed constants in HOL.thy and Orderings.thy:
   756     op +   ~> HOL.plus_class.plus
   757     op -   ~> HOL.minus_class.minus
   758     uminus ~> HOL.minus_class.uminus
   759     op *   ~> HOL.times_class.times
   760     op <   ~> Orderings.ord_class.less
   761     op <=  ~> Orderings.ord_class.less_eq
   762 
   763 Adaptions may be required in the following cases:
   764 
   765 a) User-defined constants using any of the names "plus", "minus", "times",
   766 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   767 may go wrong.
   768 INCOMPATIBILITY: use more specific names.
   769 
   770 b) Variables named "plus", "minus", "times", "less", "less_eq"
   771 INCOMPATIBILITY: use more specific names.
   772 
   773 c) Permutative equations (e.g. "a + b = b + a")
   774 Since the change of names also changes the order of terms, permutative
   775 rewrite rules may get applied in a different order. Experience shows that
   776 this is rarely the case (only two adaptions in the whole Isabelle
   777 distribution).
   778 INCOMPATIBILITY: rewrite proofs
   779 
   780 d) ML code directly refering to constant names
   781 This in general only affects hand-written proof tactics, simprocs and so on.
   782 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   783 of const_name ML antiquotations.
   784 
   785 * Relations less (<) and less_eq (<=) are also available on type bool.
   786 Modified syntax to disallow nesting without explicit parentheses,
   787 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   788 
   789 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   790 
   791 * Relation composition operator "op O" now has precedence 75 and binds
   792 stronger than union and intersection. INCOMPATIBILITY.
   793 
   794 * The old set interval syntax "{m..n(}" (and relatives) has been
   795 removed.  Use "{m..<n}" (and relatives) instead.
   796 
   797 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   798 "t = s" to False (by simproc "neq_simproc").  For backward
   799 compatibility this can be disabled by ML "reset use_neq_simproc".
   800 
   801 * "m dvd n" where m and n are numbers is evaluated to True/False by
   802 simp.
   803 
   804 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   805 
   806 * Theorem setsum_mult renamed to setsum_right_distrib.
   807 
   808 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   809 ``rule'' method.
   810 
   811 * Reimplemented methods ``sat'' and ``satx'', with several
   812 improvements: goals no longer need to be stated as "<prems> ==>
   813 False", equivalences (i.e. "=" on type bool) are handled, variable
   814 names of the form "lit_<n>" are no longer reserved, significant
   815 speedup.
   816 
   817 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   818 zChaff is still supported as well.
   819 
   820 * 'inductive' and 'datatype': provide projections of mutual rules,
   821 bundled as foo_bar.inducts;
   822 
   823 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   824 Library.
   825 
   826 * Library: moved theory Accessible_Part to main HOL.
   827 
   828 * Library: added theory Coinductive_List of potentially infinite lists
   829 as greatest fixed-point.
   830 
   831 * Library: added theory AssocList which implements (finite) maps as
   832 association lists.
   833 
   834 * Added proof method ``evaluation'' for efficiently solving a goal
   835 (i.e. a boolean expression) by compiling it to ML. The goal is
   836 "proved" (via an oracle) if it evaluates to True.
   837 
   838 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   839 also when invoked by the simplifier.  This results in the simplifier
   840 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   841 fast_arith_split_limit to 0 to obtain the old behavior.
   842 
   843 * Support for hex (0x20) and binary (0b1001) numerals.
   844 
   845 * New method: reify eqs (t), where eqs are equations for an
   846 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   847 parameter, computes a term s::'b and a list xs::'a list and proves the
   848 theorem I xs s = t. This is also known as reification or quoting. The
   849 resulting theorem is applied to the subgoal to substitute t with I xs
   850 s.  If t is omitted, the subgoal itself is reified.
   851 
   852 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   853 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   854 where f is supposed to be a computable function (in the sense of code
   855 generattion). The method uses reify to compute s and xs as above then
   856 applies corr_thm and uses normalization by evaluation to "prove" f s =
   857 r and finally gets the theorem t = r, which is again applied to the
   858 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   859 
   860 * Reflection: Automatic refification now handels binding, an example
   861 is available in HOL/ex/ReflectionEx.thy
   862 
   863 
   864 *** HOL-Algebra ***
   865 
   866 * Formalisation of ideals and the quotient construction over rings.
   867 
   868 * Order and lattice theory no longer based on records.
   869 INCOMPATIBILITY.
   870 
   871 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   872 greatest_closed.  INCOMPATIBILITY.
   873 
   874 * Method algebra is now set up via an attribute.  For examples see
   875 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   876 of algebraic structures.
   877 
   878 * Renamed theory CRing to Ring.
   879 
   880 
   881 *** HOL-Complex ***
   882 
   883 * Theory Real: new method ferrack implements quantifier elimination
   884 for linear arithmetic over the reals. The quantifier elimination
   885 feature is used only for decision, for compatibility with arith. This
   886 means a goal is either solved or left unchanged, no simplification.
   887 
   888 * Hyperreal: Functions root and sqrt are now defined on negative real
   889 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
   890 Nonnegativity side conditions have been removed from many lemmas, so
   891 that more subgoals may now be solved by simplification; potential
   892 INCOMPATIBILITY.
   893 
   894 * Real: New axiomatic classes formalize real normed vector spaces and
   895 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   896 and norm :: 'a => real.
   897 
   898 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   899 from reals into other types. The overloaded constant Reals :: 'a set
   900 is now defined as range of_real; potential INCOMPATIBILITY.
   901 
   902 * Real: ML code generation is supported now and hence also quickcheck.
   903 Reals are implemented as arbitrary precision rationals.
   904 
   905 * Hyperreal: Several constants that previously worked only for the
   906 reals have been generalized, so they now work over arbitrary vector
   907 spaces. Type annotations may need to be added in some cases; potential
   908 INCOMPATIBILITY.
   909 
   910   Infinitesimal  :: ('a::real_normed_vector) star set
   911   HFinite        :: ('a::real_normed_vector) star set
   912   HInfinite      :: ('a::real_normed_vector) star set
   913   approx         :: ('a::real_normed_vector) star => 'a star => bool
   914   monad          :: ('a::real_normed_vector) star => 'a star set
   915   galaxy         :: ('a::real_normed_vector) star => 'a star set
   916   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
   917   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   918   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   919   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   920   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   921   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   922   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   923   sgn            :: 'a::real_normed_vector => 'a
   924 
   925 * Complex: Some complex-specific constants are now abbreviations for
   926 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   927 hnorm.  Other constants have been entirely removed in favor of the
   928 polymorphic versions (INCOMPATIBILITY):
   929 
   930   approx        <-- capprox
   931   HFinite       <-- CFinite
   932   HInfinite     <-- CInfinite
   933   Infinitesimal <-- CInfinitesimal
   934   monad         <-- cmonad
   935   galaxy        <-- cgalaxy
   936   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   937   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   938   (ns)deriv     <-- (ns)cderiv
   939 
   940 
   941 *** ML ***
   942 
   943 * Context data interfaces (Theory/Proof/GenericDataFun): removed
   944 name/print, uninitialized data defaults to ad-hoc copy of empty value,
   945 init only required for impure data.  INCOMPATIBILITY: empty really
   946 need to be empty (no dependencies on theory content!)
   947 
   948 * ML within Isar: antiquotations allow to embed statically-checked
   949 formal entities in the source, referring to the context available at
   950 compile-time.  For example:
   951 
   952 ML {* @{typ "'a => 'b"} *}
   953 ML {* @{term "%x. x"} *}
   954 ML {* @{prop "x == y"} *}
   955 ML {* @{ctyp "'a => 'b"} *}
   956 ML {* @{cterm "%x. x"} *}
   957 ML {* @{cprop "x == y"} *}
   958 ML {* @{thm asm_rl} *}
   959 ML {* @{thms asm_rl} *}
   960 ML {* @{const_name c} *}
   961 ML {* @{const_syntax c} *}
   962 ML {* @{context} *}
   963 ML {* @{theory} *}
   964 ML {* @{theory Pure} *}
   965 ML {* @{simpset} *}
   966 ML {* @{claset} *}
   967 ML {* @{clasimpset} *}
   968 
   969 The same works for sources being ``used'' within an Isar context.
   970 
   971 * ML in Isar: improved error reporting; extra verbosity with
   972 Toplevel.debug enabled.
   973 
   974 * Pure/library:
   975 
   976   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   977   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   978 
   979 The semantics of "burrow" is: "take a function with *simulatanously*
   980 transforms a list of value, and apply it *simulatanously* to a list of
   981 list of values of the appropriate type". Compare this with "map" which
   982 would *not* apply its argument function simulatanously but in
   983 sequence; "fold_burrow" has an additional context.
   984 
   985 * Pure/library: functions map2 and fold2 with curried syntax for
   986 simultanous mapping and folding:
   987 
   988     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   989     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   990 
   991 * Pure/library: indexed lists - some functions in the Isabelle library
   992 treating lists over 'a as finite mappings from [0...n] to 'a have been
   993 given more convenient names and signatures reminiscent of similar
   994 functions for alists, tables, etc:
   995 
   996   val nth: 'a list -> int -> 'a 
   997   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   998   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   999 
  1000 Note that fold_index starts counting at index 0, not 1 like foldln
  1001 used to.
  1002 
  1003 * Pure/library: added general ``divide_and_conquer'' combinator on
  1004 lists.
  1005 
  1006 * Pure/General/table.ML: the join operations now works via exceptions
  1007 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1008 admits slightly more efficient complex applications.
  1009 
  1010 * Pure: datatype Context.generic joins theory/Proof.context and
  1011 provides some facilities for code that works in either kind of
  1012 context, notably GenericDataFun for uniform theory and proof data.
  1013 
  1014 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1015 use Context.generic instead of just theory.
  1016 
  1017 * Pure: simplified internal attribute type, which is now always
  1018 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1019 vs. local (Proof.context) attributes have been discontinued, while
  1020 minimizing code duplication.  Thm.rule_attribute and
  1021 Thm.declaration_attribute build canonical attributes; see also
  1022 structure Context for further operations on Context.generic, notably
  1023 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1024 declarations and definitions.
  1025 
  1026 * Pure/kernel: consts certification ignores sort constraints given in
  1027 signature declarations.  (This information is not relevant to the
  1028 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1029 potential INCOMPATIBILITY.
  1030 
  1031 * Pure: axiomatic type classes are now purely definitional, with
  1032 explicit proofs of class axioms and super class relations performed
  1033 internally.  See Pure/axclass.ML for the main internal interfaces --
  1034 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1035 AxClass.axiomatize_class/classrel/arity supercede
  1036 Sign.add_classes/classrel/arities.
  1037 
  1038 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1039 global/local versions on theory vs. Proof.context have been
  1040 discontinued; Attrib.syntax and Method.syntax have been adapted
  1041 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1042 attributes, methods, etc.
  1043 
  1044 * Pure: several functions of signature "... -> theory -> theory * ..."
  1045 have been reoriented to "... -> theory -> ... * theory" in order to
  1046 allow natural usage in combination with the ||>, ||>>, |-> and
  1047 fold_map combinators.
  1048 
  1049 * Pure: official theorem names (closed derivations) and additional
  1050 comments (tags) are now strictly separate.  Name hints -- which are
  1051 maintained as tags -- may be attached any time without affecting the
  1052 derivation.
  1053 
  1054 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1055 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1056 achieve the old behaviour.
  1057 
  1058 * Pure: the "Goal" constant is now called "prop", supporting a
  1059 slightly more general idea of ``protecting'' meta-level rule
  1060 statements.
  1061 
  1062 * Pure: Logic.(un)varify only works in a global context, which is now
  1063 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1064 Logic.legacy_(un)varify as temporary workaround.
  1065 
  1066 * Pure: structure Name provides scalable operations for generating
  1067 internal variable names, notably Name.variants etc.  This replaces
  1068 some popular functions from term.ML:
  1069 
  1070   Term.variant		->  Name.variant
  1071   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1072   Term.invent_names	->  Name.invent_list
  1073 
  1074 Note that low-level renaming rarely occurs in new code -- operations
  1075 from structure Variable are used instead (see below).
  1076 
  1077 * Pure: structure Variable provides fundamental operations for proper
  1078 treatment of fixed/schematic variables in a context.  For example,
  1079 Variable.import introduces fixes for schematics of given facts and
  1080 Variable.export reverses the effect (up to renaming) -- this replaces
  1081 various freeze_thaw operations.
  1082 
  1083 * Pure: structure Goal provides simple interfaces for
  1084 init/conclude/finish and tactical prove operations (replacing former
  1085 Tactic.prove).  Goal.prove is the canonical way to prove results
  1086 within a given context; Goal.prove_global is a degraded version for
  1087 theory level goals, including a global Drule.standard.  Note that
  1088 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1089 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1090 in a locale context).
  1091 
  1092 * Isar: simplified treatment of user-level errors, using exception
  1093 ERROR of string uniformly.  Function error now merely raises ERROR,
  1094 without any side effect on output channels.  The Isar toplevel takes
  1095 care of proper display of ERROR exceptions.  ML code may use plain
  1096 handle/can/try; cat_error may be used to concatenate errors like this:
  1097 
  1098   ... handle ERROR msg => cat_error msg "..."
  1099 
  1100 Toplevel ML code (run directly or through the Isar toplevel) may be
  1101 embedded into the Isar toplevel with exception display/debug like
  1102 this:
  1103 
  1104   Isar.toplevel (fn () => ...)
  1105 
  1106 INCOMPATIBILITY, removed special transform_error facilities, removed
  1107 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1108 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1109 -- use plain ERROR instead.
  1110 
  1111 * Isar: theory setup now has type (theory -> theory), instead of a
  1112 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1113 
  1114 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1115 subject to ProofContext.debug/verbose flags.
  1116 
  1117 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1118 theory before entering a proof state.  Transactions now always see a
  1119 quasi-functional intermediate checkpoint, both in interactive and
  1120 batch mode.
  1121 
  1122 * Simplifier: the simpset of a running simplification process now
  1123 contains a proof context (cf. Simplifier.the_context), which is the
  1124 very context that the initial simpset has been retrieved from (by
  1125 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1126 (solver, looper etc.) may depend on arbitrary proof data.
  1127 
  1128 * Simplifier.inherit_context inherits the proof context (plus the
  1129 local bounds) of the current simplification process; any simproc
  1130 etc. that calls the Simplifier recursively should do this!  Removed
  1131 former Simplifier.inherit_bounds, which is already included here --
  1132 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1133 specify an explicit context using Simplifier.context/theory_context.
  1134 
  1135 * Simplifier/Classical Reasoner: more abstract interfaces
  1136 change_simpset/claset for modifying the simpset/claset reference of a
  1137 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1138 INCOMPATIBILITY.
  1139 
  1140 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1141 "Trueprop" etc.
  1142 
  1143 
  1144 *** System ***
  1145 
  1146 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1147 locations -- now includes the Isabelle version identifier as well.
  1148 This simplifies use of multiple Isabelle installations.
  1149 
  1150 * isabelle-process: option -S (secure mode) disables some critical
  1151 operations, notably runtime compilation and evaluation of ML source
  1152 code.
  1153 
  1154 
  1155 New in Isabelle2005 (October 2005)
  1156 ----------------------------------
  1157 
  1158 *** General ***
  1159 
  1160 * Theory headers: the new header syntax for Isar theories is
  1161 
  1162   theory <name>
  1163   imports <theory1> ... <theoryN>
  1164   uses <file1> ... <fileM>
  1165   begin
  1166 
  1167 where the 'uses' part is optional.  The previous syntax
  1168 
  1169   theory <name> = <theory1> + ... + <theoryN>:
  1170 
  1171 will disappear in the next release.  Use isatool fixheaders to convert
  1172 existing theory files.  Note that there is no change in ancient
  1173 non-Isar theories now, but these will disappear soon.
  1174 
  1175 * Theory loader: parent theories can now also be referred to via
  1176 relative and absolute paths.
  1177 
  1178 * Command 'find_theorems' searches for a list of criteria instead of a
  1179 list of constants. Known criteria are: intro, elim, dest, name:string,
  1180 simp:term, and any term. Criteria can be preceded by '-' to select
  1181 theorems that do not match. Intro, elim, dest select theorems that
  1182 match the current goal, name:s selects theorems whose fully qualified
  1183 name contain s, and simp:term selects all simplification rules whose
  1184 lhs match term.  Any other term is interpreted as pattern and selects
  1185 all theorems matching the pattern. Available in ProofGeneral under
  1186 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1187 
  1188   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1189 
  1190 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1191 matching the current goal as introduction rule and not having "HOL."
  1192 in their name (i.e. not being defined in theory HOL).
  1193 
  1194 * Command 'thms_containing' has been discontinued in favour of
  1195 'find_theorems'; INCOMPATIBILITY.
  1196 
  1197 * Communication with Proof General is now 8bit clean, which means that
  1198 Unicode text in UTF-8 encoding may be used within theory texts (both
  1199 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1200 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1201 
  1202   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1203   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1204 
  1205 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1206 Classical Reasoner.  Typical big applications run around 2 times
  1207 faster.
  1208 
  1209 
  1210 *** Document preparation ***
  1211 
  1212 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1213 of raw sources.  Only those symbols that do not require additional
  1214 LaTeX packages (depending on comments in isabellesym.sty) are
  1215 displayed properly, everything else is left verbatim.  isatool display
  1216 and isatool print are used as front ends (these are subject to the
  1217 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1218 
  1219 * Command tags control specific markup of certain regions of text,
  1220 notably folding and hiding.  Predefined tags include "theory" (for
  1221 theory begin and end), "proof" for proof commands, and "ML" for
  1222 commands involving ML code; the additional tags "visible" and
  1223 "invisible" are unused by default.  Users may give explicit tag
  1224 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1225 interpretation of tags is determined by the LaTeX job during document
  1226 preparation: see option -V of isatool usedir, or options -n and -t of
  1227 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1228 \isadroptag.
  1229 
  1230 Several document versions may be produced at the same time via isatool
  1231 usedir (the generated index.html will link all of them).  Typical
  1232 specifications include ''-V document=theory,proof,ML'' to present
  1233 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1234 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1235 these parts without any formal replacement text.  The Isabelle site
  1236 default settings produce ''document'' and ''outline'' versions as
  1237 specified above.
  1238 
  1239 * Several new antiquotations:
  1240 
  1241   @{term_type term} prints a term with its type annotated;
  1242 
  1243   @{typeof term} prints the type of a term;
  1244 
  1245   @{const const} is the same as @{term const}, but checks that the
  1246   argument is a known logical constant;
  1247 
  1248   @{term_style style term} and @{thm_style style thm} print a term or
  1249   theorem applying a "style" to it
  1250 
  1251   @{ML text}
  1252 
  1253 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1254 definitions, equations, inequations etc., 'concl' printing only the
  1255 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1256 to print the specified premise.  TermStyle.add_style provides an ML
  1257 interface for introducing further styles.  See also the "LaTeX Sugar"
  1258 document practical applications.  The ML antiquotation prints
  1259 type-checked ML expressions verbatim.
  1260 
  1261 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1262 and 'text' support optional locale specification '(in loc)', which
  1263 specifies the default context for interpreting antiquotations.  For
  1264 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1265 
  1266 * Option 'locale=NAME' of antiquotations specifies an alternative
  1267 context interpreting the subsequent argument.  For example: @{thm
  1268 [locale=lattice] inf_assoc}.
  1269 
  1270 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1271 a proof context.
  1272 
  1273 * Proper output of antiquotations for theory commands involving a
  1274 proof context (such as 'locale' or 'theorem (in loc) ...').
  1275 
  1276 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1277 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1278 
  1279 * isatool usedir: new option -C (default true) controls whether option
  1280 -D should include a copy of the original document directory; -C false
  1281 prevents unwanted effects such as copying of administrative CVS data.
  1282 
  1283 
  1284 *** Pure ***
  1285 
  1286 * Considerably improved version of 'constdefs' command.  Now performs
  1287 automatic type-inference of declared constants; additional support for
  1288 local structure declarations (cf. locales and HOL records), see also
  1289 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1290 sequential dependencies of definitions within a single 'constdefs'
  1291 section; moreover, the declared name needs to be an identifier.  If
  1292 all fails, consider to fall back on 'consts' and 'defs' separately.
  1293 
  1294 * Improved indexed syntax and implicit structures.  First of all,
  1295 indexed syntax provides a notational device for subscripted
  1296 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1297 expressions.  Secondly, in a local context with structure
  1298 declarations, number indexes \<^sub>n or the empty index (default
  1299 number 1) refer to a certain fixed variable implicitly; option
  1300 show_structs controls printing of implicit structures.  Typical
  1301 applications of these concepts involve record types and locales.
  1302 
  1303 * New command 'no_syntax' removes grammar declarations (and
  1304 translations) resulting from the given syntax specification, which is
  1305 interpreted in the same manner as for the 'syntax' command.
  1306 
  1307 * 'Advanced' translation functions (parse_translation etc.) may depend
  1308 on the signature of the theory context being presently used for
  1309 parsing/printing, see also isar-ref manual.
  1310 
  1311 * Improved 'oracle' command provides a type-safe interface to turn an
  1312 ML expression of type theory -> T -> term into a primitive rule of
  1313 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1314 is already included here); see also FOL/ex/IffExample.thy;
  1315 INCOMPATIBILITY.
  1316 
  1317 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1318 before); "cI" is no longer bound, use "c.intro" instead.
  1319 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1320 axclasses vs. locales.
  1321 
  1322 * Improved internal renaming of symbolic identifiers -- attach primes
  1323 instead of base 26 numbers.
  1324 
  1325 * New flag show_question_marks controls printing of leading question
  1326 marks in schematic variable names.
  1327 
  1328 * In schematic variable names, *any* symbol following \<^isub> or
  1329 \<^isup> is now treated as part of the base name.  For example, the
  1330 following works without printing of awkward ".0" indexes:
  1331 
  1332   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1333     by simp
  1334 
  1335 * Inner syntax includes (*(*nested*) comments*).
  1336 
  1337 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1338 annotations as "(00...)".
  1339 
  1340 * Clear separation of logical types and nonterminals, where the latter
  1341 may only occur in 'syntax' specifications or type abbreviations.
  1342 Before that distinction was only partially implemented via type class
  1343 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1344 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1345 exotic syntax specifications may require further adaption
  1346 (e.g. Cube/Cube.thy).
  1347 
  1348 * Removed obsolete type class "logic", use the top sort {} instead.
  1349 Note that non-logical types should be declared as 'nonterminals'
  1350 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1351 specifications.
  1352 
  1353 * Attributes 'induct' and 'cases': type or set names may now be
  1354 locally fixed variables as well.
  1355 
  1356 * Simplifier: can now control the depth to which conditional rewriting
  1357 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1358 Limit.
  1359 
  1360 * Simplifier: simplification procedures may now take the current
  1361 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1362 interface), which is very useful for calling the Simplifier
  1363 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1364 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1365 low-level mk_simproc no longer applies Logic.varify internally, to
  1366 allow for use in a context of fixed variables.
  1367 
  1368 * thin_tac now works even if the assumption being deleted contains !!
  1369 or ==>.  More generally, erule now works even if the major premise of
  1370 the elimination rule contains !! or ==>.
  1371 
  1372 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1373 
  1374 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1375 from Pure, which contains all common declarations already.  Both
  1376 theories are defined via plain Isabelle/Isar .thy files.
  1377 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1378 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1379 use isatool fixcpure to adapt your theory and ML sources.
  1380 
  1381 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1382 selections of theorems in named facts via index ranges.
  1383 
  1384 * 'print_theorems': in theory mode, really print the difference
  1385 wrt. the last state (works for interactive theory development only),
  1386 in proof mode print all local facts (cf. 'print_facts');
  1387 
  1388 * 'hide': option '(open)' hides only base names.
  1389 
  1390 * More efficient treatment of intermediate checkpoints in interactive
  1391 theory development.
  1392 
  1393 * Code generator is now invoked via code_module (incremental code
  1394 generation) and code_library (modular code generation, ML structures
  1395 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1396 must be quoted when used as identifiers.
  1397 
  1398 * New 'value' command for reading, evaluating and printing terms using
  1399 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1400 quoted when used as identifier.
  1401 
  1402 
  1403 *** Locales ***
  1404 
  1405 * New commands for the interpretation of locale expressions in
  1406 theories (1), locales (2) and proof contexts (3).  These generate
  1407 proof obligations from the expression specification.  After the
  1408 obligations have been discharged, theorems of the expression are added
  1409 to the theory, target locale or proof context.  The synopsis of the
  1410 commands is a follows:
  1411 
  1412   (1) interpretation expr inst
  1413   (2) interpretation target < expr
  1414   (3) interpret expr inst
  1415 
  1416 Interpretation in theories and proof contexts require a parameter
  1417 instantiation of terms from the current context.  This is applied to
  1418 specifications and theorems of the interpreted expression.
  1419 Interpretation in locales only permits parameter renaming through the
  1420 locale expression.  Interpretation is smart in that interpretations
  1421 that are active already do not occur in proof obligations, neither are
  1422 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1423 inspect active interpretations of a particular locale.  For details,
  1424 see the Isar Reference manual.  Examples can be found in
  1425 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1426 
  1427 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1428 'interpret' instead.
  1429 
  1430 * New context element 'constrains' for adding type constraints to
  1431 parameters.
  1432 
  1433 * Context expressions: renaming of parameters with syntax
  1434 redeclaration.
  1435 
  1436 * Locale declaration: 'includes' disallowed.
  1437 
  1438 * Proper static binding of attribute syntax -- i.e. types / terms /
  1439 facts mentioned as arguments are always those of the locale definition
  1440 context, independently of the context of later invocations.  Moreover,
  1441 locale operations (renaming and type / term instantiation) are applied
  1442 to attribute arguments as expected.
  1443 
  1444 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1445 actual attributes; rare situations may require Attrib.attribute to
  1446 embed those attributes into Attrib.src that lack concrete syntax.
  1447 Attribute implementations need to cooperate properly with the static
  1448 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1449 Attrib.XXX_thm etc. already do the right thing without further
  1450 intervention.  Only unusual applications -- such as "where" or "of"
  1451 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1452 on the context and the facts involved -- may have to assign parsed
  1453 values to argument tokens explicitly.
  1454 
  1455 * Changed parameter management in theorem generation for long goal
  1456 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1457 theorem statement in rare situations.
  1458 
  1459 * Locale inspection command 'print_locale' omits notes elements.  Use
  1460 'print_locale!' to have them included in the output.
  1461 
  1462 
  1463 *** Provers ***
  1464 
  1465 * Provers/hypsubst.ML: improved version of the subst method, for
  1466 single-step rewriting: it now works in bound variable contexts. New is
  1467 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1468 rewrite a different subterm than the original subst method, which is
  1469 still available as 'simplesubst'.
  1470 
  1471 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1472 and quasi orders.
  1473 
  1474 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1475 reflexive-transitive closure of relations.
  1476 
  1477 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1478 limit (previously hard-coded with a value of 20) user-definable.
  1479 
  1480 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1481 is peformed already.  Object-logics merely need to finish their
  1482 initial simpset configuration as before.  INCOMPATIBILITY.
  1483 
  1484 
  1485 *** HOL ***
  1486 
  1487 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1488 
  1489   syntax (epsilon)
  1490     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1491 
  1492 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1493 and x-symbol; use option '-m epsilon' to get it actually printed.
  1494 Moreover, the mathematically important symbolic identifier \<epsilon>
  1495 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1496 
  1497 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1498 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1499 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1500 support corresponding Isar calculations.
  1501 
  1502 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1503 instead of ":".
  1504 
  1505 * theory SetInterval: changed the syntax for open intervals:
  1506 
  1507   Old       New
  1508   {..n(}    {..<n}
  1509   {)n..}    {n<..}
  1510   {m..n(}   {m..<n}
  1511   {)m..n}   {m<..n}
  1512   {)m..n(}  {m<..<n}
  1513 
  1514 The old syntax is still supported but will disappear in the next
  1515 release.  For conversion use the following Emacs search and replace
  1516 patterns (these are not perfect but work quite well):
  1517 
  1518   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1519   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1520 
  1521 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1522 equalities in commutative rings; method 'algebra' provides a generic
  1523 interface.
  1524 
  1525 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1526 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1527 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1528 be a tuple pattern.
  1529 
  1530 Some new syntax forms are available:
  1531 
  1532   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1533   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1534   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1535   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1536 
  1537 The latter form "\<Sum>x < k. e" used to be based on a separate
  1538 function "Summation", which has been discontinued.
  1539 
  1540 * theory Finite_Set: in structured induction proofs, the insert case
  1541 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1542 (insert F x)'.
  1543 
  1544 * The 'refute' command has been extended to support a much larger
  1545 fragment of HOL, including axiomatic type classes, constdefs and
  1546 typedefs, inductive datatypes and recursion.
  1547 
  1548 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1549 Requires zChaff with proof generation to be installed.  See
  1550 HOL/ex/SAT_Examples.thy for examples.
  1551 
  1552 * Datatype induction via method 'induct' now preserves the name of the
  1553 induction variable. For example, when proving P(xs::'a list) by
  1554 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1555 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1556 in unstructured proof scripts.
  1557 
  1558 * Reworked implementation of records.  Improved scalability for
  1559 records with many fields, avoiding performance problems for type
  1560 inference. Records are no longer composed of nested field types, but
  1561 of nested extension types. Therefore the record type only grows linear
  1562 in the number of extensions and not in the number of fields.  The
  1563 top-level (users) view on records is preserved.  Potential
  1564 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1565 old record representation. The type generated for a record is called
  1566 <record_name>_ext_type.
  1567 
  1568 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1569 proofs triggered by a record definition or a simproc (if
  1570 quick_and_dirty is enabled).  Definitions of large records can take
  1571 quite long.
  1572 
  1573 New simproc record_upd_simproc for simplification of multiple record
  1574 updates enabled by default.  Moreover, trivial updates are also
  1575 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1576 occasionally, since simplification is more powerful by default.
  1577 
  1578 * typedef: proper support for polymorphic sets, which contain extra
  1579 type-variables in the term.
  1580 
  1581 * Simplifier: automatically reasons about transitivity chains
  1582 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1583 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1584 old proofs break occasionally as simplification may now solve more
  1585 goals than previously.
  1586 
  1587 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1588 present.  Works for all partial orders (class "order"), in particular
  1589 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1590 just like y <= x.
  1591 
  1592 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1593 bound variable or a constant then the let is unfolded.  Otherwise
  1594 first a is simplified to b, and then f b is simplified to g. If
  1595 possible we abstract b from g arriving at "let x = b in h x",
  1596 otherwise we unfold the let and arrive at g.  The simproc can be
  1597 enabled/disabled by the reference use_let_simproc.  Potential
  1598 INCOMPATIBILITY since simplification is more powerful by default.
  1599 
  1600 * Classical reasoning: the meson method now accepts theorems as arguments.
  1601 
  1602 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1603 jobs to provide advice on the provability of subgoals.
  1604 
  1605 * Theory OrderedGroup and Ring_and_Field: various additions and
  1606 improvements to faciliate calculations involving equalities and
  1607 inequalities.
  1608 
  1609 The following theorems have been eliminated or modified
  1610 (INCOMPATIBILITY):
  1611 
  1612   abs_eq             now named abs_of_nonneg
  1613   abs_of_ge_0        now named abs_of_nonneg
  1614   abs_minus_eq       now named abs_of_nonpos
  1615   imp_abs_id         now named abs_of_nonneg
  1616   imp_abs_neg_id     now named abs_of_nonpos
  1617   mult_pos           now named mult_pos_pos
  1618   mult_pos_le        now named mult_nonneg_nonneg
  1619   mult_pos_neg_le    now named mult_nonneg_nonpos
  1620   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1621   mult_neg           now named mult_neg_neg
  1622   mult_neg_le        now named mult_nonpos_nonpos
  1623 
  1624 * Theory Parity: added rules for simplifying exponents.
  1625 
  1626 * Theory List:
  1627 
  1628 The following theorems have been eliminated or modified
  1629 (INCOMPATIBILITY):
  1630 
  1631   list_all_Nil       now named list_all.simps(1)
  1632   list_all_Cons      now named list_all.simps(2)
  1633   list_all_conv      now named list_all_iff
  1634   set_mem_eq         now named mem_iff
  1635 
  1636 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1637 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1638 
  1639 
  1640 *** HOL-Complex ***
  1641 
  1642 * Theory RealDef: better support for embedding natural numbers and
  1643 integers in the reals.
  1644 
  1645 The following theorems have been eliminated or modified
  1646 (INCOMPATIBILITY):
  1647 
  1648   exp_ge_add_one_self  now requires no hypotheses
  1649   real_of_int_add      reversed direction of equality (use [symmetric])
  1650   real_of_int_minus    reversed direction of equality (use [symmetric])
  1651   real_of_int_diff     reversed direction of equality (use [symmetric])
  1652   real_of_int_mult     reversed direction of equality (use [symmetric])
  1653 
  1654 * Theory RComplete: expanded support for floor and ceiling functions.
  1655 
  1656 * Theory Ln is new, with properties of the natural logarithm
  1657 
  1658 * Hyperreal: There is a new type constructor "star" for making
  1659 nonstandard types.  The old type names are now type synonyms:
  1660 
  1661   hypreal = real star
  1662   hypnat = nat star
  1663   hcomplex = complex star
  1664 
  1665 * Hyperreal: Many groups of similarly-defined constants have been
  1666 replaced by polymorphic versions (INCOMPATIBILITY):
  1667 
  1668   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1669 
  1670   starset      <-- starsetNat, starsetC
  1671   *s*          <-- *sNat*, *sc*
  1672   starset_n    <-- starsetNat_n, starsetC_n
  1673   *sn*         <-- *sNatn*, *scn*
  1674   InternalSets <-- InternalNatSets, InternalCSets
  1675 
  1676   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1677   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1678   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1679   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1680   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1681 
  1682 * Hyperreal: Many type-specific theorems have been removed in favor of
  1683 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1684 
  1685   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1686   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1687   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1688   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1689   right_minus <-- hypreal_add_minus
  1690   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1691   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1692   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1693   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1694   mult_1_right <-- hcomplex_mult_one_right
  1695   mult_zero_left <-- hcomplex_mult_zero_left
  1696   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1697   right_distrib <-- hypnat_add_mult_distrib2
  1698   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1699   right_inverse <-- hypreal_mult_inverse
  1700   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1701   order_refl <-- {hypreal,hypnat}_le_refl
  1702   order_trans <-- {hypreal,hypnat}_le_trans
  1703   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1704   order_less_le <-- {hypreal,hypnat}_less_le
  1705   linorder_linear <-- {hypreal,hypnat}_le_linear
  1706   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1707   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1708   add_nonneg_nonneg <-- hypreal_le_add_order
  1709 
  1710 * Hyperreal: Separate theorems having to do with type-specific
  1711 versions of constants have been merged into theorems that apply to the
  1712 new polymorphic constants (INCOMPATIBILITY):
  1713 
  1714   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1715   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1716   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1717   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1718   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1719   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1720   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1721   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1722   STAR_diff <-- {STAR,STARC}_diff
  1723   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1724     STARC_hcomplex_of_complex}_image_subset
  1725   starset_n_Un <-- starset{Nat,C}_n_Un
  1726   starset_n_Int <-- starset{Nat,C}_n_Int
  1727   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1728   starset_n_diff <-- starset{Nat,C}_n_diff
  1729   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1730   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1731   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1732   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1733   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1734   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1735   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1736   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1737   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1738   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1739   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1740   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1741   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1742   starfun_diff <-- starfun{C,RC,CR}_diff
  1743   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1744   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1745   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1746   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1747   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1748   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1749   starfun_Id <-- starfunC_Id
  1750   starfun_approx <-- starfun{Nat,CR}_approx
  1751   starfun_capprox <-- starfun{C,RC}_capprox
  1752   starfun_abs <-- starfunNat_rabs
  1753   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1754   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1755   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1756   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1757   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1758   starfun_add_approx <-- starfunCR_add_approx
  1759   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1760   starfun_divide <-- starfun{C,CR,RC}_divide
  1761   starfun_n <-- starfun{Nat,C}_n
  1762   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1763   starfun_n_add <-- starfun{Nat,C}_n_add
  1764   starfun_n_add_minus <-- starfunNat_n_add_minus
  1765   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1766   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1767   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1768 
  1769   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1770   star_n_minus <-- {hypreal,hcomplex}_minus
  1771   star_n_diff <-- {hypreal,hcomplex}_diff
  1772   star_n_mult <-- {hypreal,hcomplex}_mult
  1773   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1774   star_n_le <-- {hypreal,hypnat}_le
  1775   star_n_less <-- {hypreal,hypnat}_less
  1776   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1777   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1778   star_n_abs <-- hypreal_hrabs
  1779   star_n_divide <-- hcomplex_divide
  1780 
  1781   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1782   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1783   star_of_diff <-- hypreal_of_real_diff
  1784   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1785   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1786   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1787   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1788   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1789   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1790   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1791   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1792   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1793   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1794   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1795   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1796   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1797   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1798   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1799   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1800   star_of_power <-- hypreal_of_real_power
  1801   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1802 
  1803 * Hyperreal: new method "transfer" that implements the transfer
  1804 principle of nonstandard analysis. With a subgoal that mentions
  1805 nonstandard types like "'a star", the command "apply transfer"
  1806 replaces it with an equivalent one that mentions only standard types.
  1807 To be successful, all free variables must have standard types; non-
  1808 standard variables must have explicit universal quantifiers.
  1809 
  1810 * Hyperreal: A theory of Taylor series.
  1811 
  1812 
  1813 *** HOLCF ***
  1814 
  1815 * Discontinued special version of 'constdefs' (which used to support
  1816 continuous functions) in favor of the general Pure one with full
  1817 type-inference.
  1818 
  1819 * New simplification procedure for solving continuity conditions; it
  1820 is much faster on terms with many nested lambda abstractions (cubic
  1821 instead of exponential time).
  1822 
  1823 * New syntax for domain package: selector names are now optional.
  1824 Parentheses should be omitted unless argument is lazy, for example:
  1825 
  1826   domain 'a stream = cons "'a" (lazy "'a stream")
  1827 
  1828 * New command 'fixrec' for defining recursive functions with pattern
  1829 matching; defining multiple functions with mutual recursion is also
  1830 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1831 sinr, or any data constructor defined by the domain package. The given
  1832 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1833 syntax and examples.
  1834 
  1835 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1836 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1837 but the proof obligation additionally includes an admissibility
  1838 requirement. The packages generate instances of class cpo or pcpo,
  1839 with continuity and strictness theorems for Rep and Abs.
  1840 
  1841 * HOLCF: Many theorems have been renamed according to a more standard naming
  1842 scheme (INCOMPATIBILITY):
  1843 
  1844   foo_inject:  "foo$x = foo$y ==> x = y"
  1845   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1846   foo_less:    "(foo$x << foo$y) = (x << y)"
  1847   foo_strict:  "foo$UU = UU"
  1848   foo_defined: "... ==> foo$x ~= UU"
  1849   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1850 
  1851 
  1852 *** ZF ***
  1853 
  1854 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1855 including the First Isomorphism Theorem (on quotienting by the kernel
  1856 of a homomorphism).
  1857 
  1858 * ZF/Simplifier: install second copy of type solver that actually
  1859 makes use of TC rules declared to Isar proof contexts (or locales);
  1860 the old version is still required for ML proof scripts.
  1861 
  1862 
  1863 *** Cube ***
  1864 
  1865 * Converted to Isar theory format; use locales instead of axiomatic
  1866 theories.
  1867 
  1868 
  1869 *** ML ***
  1870 
  1871 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1872 for ||>, ||>>, |>>,
  1873 
  1874 * Pure/library.ML no longer defines its own option datatype, but uses
  1875 that of the SML basis, which has constructors NONE and SOME instead of
  1876 None and Some, as well as exception Option.Option instead of OPTION.
  1877 The functions the, if_none, is_some, is_none have been adapted
  1878 accordingly, while Option.map replaces apsome.
  1879 
  1880 * Pure/library.ML: the exception LIST has been given up in favour of
  1881 the standard exceptions Empty and Subscript, as well as
  1882 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1883 superceded by the standard hd and tl functions etc.
  1884 
  1885 A number of basic list functions are no longer exported to the ML
  1886 toplevel, as they are variants of predefined functions.  The following
  1887 suggests how one can translate existing code:
  1888 
  1889     rev_append xs ys = List.revAppend (xs, ys)
  1890     nth_elem (i, xs) = List.nth (xs, i)
  1891     last_elem xs = List.last xs
  1892     flat xss = List.concat xss
  1893     seq fs = List.app fs
  1894     partition P xs = List.partition P xs
  1895     mapfilter f xs = List.mapPartial f xs
  1896 
  1897 * Pure/library.ML: several combinators for linear functional
  1898 transformations, notably reverse application and composition:
  1899 
  1900   x |> f                f #> g
  1901   (x, y) |-> f          f #-> g
  1902 
  1903 * Pure/library.ML: introduced/changed precedence of infix operators:
  1904 
  1905   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1906   infix 2 ?;
  1907   infix 3 o oo ooo oooo;
  1908   infix 4 ~~ upto downto;
  1909 
  1910 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1911 infix operators.
  1912 
  1913 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1914 fold_map support linear functional transformations and nesting.  For
  1915 example:
  1916 
  1917   fold f [x1, ..., xN] y =
  1918     y |> f x1 |> ... |> f xN
  1919 
  1920   (fold o fold) f [xs1, ..., xsN] y =
  1921     y |> fold f xs1 |> ... |> fold f xsN
  1922 
  1923   fold f [x1, ..., xN] =
  1924     f x1 #> ... #> f xN
  1925 
  1926   (fold o fold) f [xs1, ..., xsN] =
  1927     fold f xs1 #> ... #> fold f xsN
  1928 
  1929 * Pure/library.ML: the following selectors on type 'a option are
  1930 available:
  1931 
  1932   the:               'a option -> 'a  (*partial*)
  1933   these:             'a option -> 'a  where 'a = 'b list
  1934   the_default: 'a -> 'a option -> 'a
  1935   the_list:          'a option -> 'a list
  1936 
  1937 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1938 basic operations for association lists, following natural argument
  1939 order; moreover the explicit equality predicate passed here avoids
  1940 potentially expensive polymorphic runtime equality checks.
  1941 The old functions may be expressed as follows:
  1942 
  1943   assoc = uncurry (AList.lookup (op =))
  1944   assocs = these oo AList.lookup (op =)
  1945   overwrite = uncurry (AList.update (op =)) o swap
  1946 
  1947 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1948 
  1949   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1950   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1951 
  1952 replacing make_keylist and keyfilter (occassionally used)
  1953 Naive rewrites:
  1954 
  1955   make_keylist = AList.make
  1956   keyfilter = AList.find (op =)
  1957 
  1958 * eq_fst and eq_snd now take explicit equality parameter, thus
  1959   avoiding eqtypes. Naive rewrites:
  1960 
  1961     eq_fst = eq_fst (op =)
  1962     eq_snd = eq_snd (op =)
  1963 
  1964 * Removed deprecated apl and apr (rarely used).
  1965   Naive rewrites:
  1966 
  1967     apl (n, op) =>>= curry op n
  1968     apr (op, m) =>>= fn n => op (n, m)
  1969 
  1970 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1971 provides a reasonably efficient light-weight implementation of sets as
  1972 lists.
  1973 
  1974 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1975 few new operations; existing lookup and update are now curried to
  1976 follow natural argument order (for use with fold etc.);
  1977 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1978 
  1979 * Pure/General: output via the Isabelle channels of
  1980 writeln/warning/error etc. is now passed through Output.output, with a
  1981 hook for arbitrary transformations depending on the print_mode
  1982 (cf. Output.add_mode -- the first active mode that provides a output
  1983 function wins).  Already formatted output may be embedded into further
  1984 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1985 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1986 accommodate easy composition of diagnostic messages etc.  Programmers
  1987 rarely need to care about Output.output or Output.raw at all, with
  1988 some notable exceptions: Output.output is required when bypassing the
  1989 standard channels (writeln etc.), or in token translations to produce
  1990 properly formatted results; Output.raw is required when capturing
  1991 already output material that will eventually be presented to the user
  1992 a second time.  For the default print mode, both Output.output and
  1993 Output.raw have no effect.
  1994 
  1995 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1996 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1997 cumulative results are displayed at the end of a batch session.
  1998 
  1999 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2000 replaced by File.platform_path and File.shell_path (with appropriate
  2001 hooks).  This provides a clean interface for unusual systems where the
  2002 internal and external process view of file names are different.
  2003 
  2004 * Pure: more efficient orders for basic syntactic entities: added
  2005 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2006 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2007 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2008 orders now -- potential INCOMPATIBILITY for code that depends on a
  2009 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2010 Library.sort_strings on result).
  2011 
  2012 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2013 fold_types traverse types/terms from left to right, observing natural
  2014 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2015 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2016 
  2017 * Pure: name spaces have been refined, with significant changes of the
  2018 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2019 to extern(_table).  The plain name entry path is superceded by a
  2020 general 'naming' context, which also includes the 'policy' to produce
  2021 a fully qualified name and external accesses of a fully qualified
  2022 name; NameSpace.extend is superceded by context dependent
  2023 Sign.declare_name.  Several theory and proof context operations modify
  2024 the naming context.  Especially note Theory.restore_naming and
  2025 ProofContext.restore_naming to get back to a sane state; note that
  2026 Theory.add_path is no longer sufficient to recover from
  2027 Theory.absolute_path in particular.
  2028 
  2029 * Pure: new flags short_names (default false) and unique_names
  2030 (default true) for controlling output of qualified names.  If
  2031 short_names is set, names are printed unqualified.  If unique_names is
  2032 reset, the name prefix is reduced to the minimum required to achieve
  2033 the original result when interning again, even if there is an overlap
  2034 with earlier declarations.
  2035 
  2036 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2037 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2038 (useful for printing error messages).  INCOMPATIBILITY.
  2039 
  2040 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2041 Theory.theory are now identified, referring to the universal
  2042 Context.theory (see Pure/context.ML).  Actual signature and theory
  2043 content is managed as theory data.  The old code and interfaces were
  2044 spread over many files and structures; the new arrangement introduces
  2045 considerable INCOMPATIBILITY to gain more clarity:
  2046 
  2047   Context -- theory management operations (name, identity, inclusion,
  2048     parents, ancestors, merge, etc.), plus generic theory data;
  2049 
  2050   Sign -- logical signature and syntax operations (declaring consts,
  2051     types, etc.), plus certify/read for common entities;
  2052 
  2053   Theory -- logical theory operations (stating axioms, definitions,
  2054     oracles), plus a copy of logical signature operations (consts,
  2055     types, etc.); also a few basic management operations (Theory.copy,
  2056     Theory.merge, etc.)
  2057 
  2058 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2059 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2060 for convenience -- they merely return the theory.
  2061 
  2062 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2063 
  2064 * Pure: the Isar proof context type is already defined early in Pure
  2065 as Context.proof (note that ProofContext.context and Proof.context are
  2066 aliases, where the latter is the preferred name).  This enables other
  2067 Isabelle components to refer to that type even before Isar is present.
  2068 
  2069 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2070 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2071 any of these kinds.  For example, Sign.intern typeK is now
  2072 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2073 Theory.hide_types.  Also note that former
  2074 Theory.hide_classes/types/consts are now
  2075 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2076 internalize their arguments!  INCOMPATIBILITY.
  2077 
  2078 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2079 datatype thmref (with constructors Name and NameSelection) instead of
  2080 plain string -- INCOMPATIBILITY;
  2081 
  2082 * Pure: cases produced by proof methods specify options, where NONE
  2083 means to remove case bindings -- INCOMPATIBILITY in
  2084 (RAW_)METHOD_CASES.
  2085 
  2086 * Pure: the following operations retrieve axioms or theorems from a
  2087 theory node or theory hierarchy, respectively:
  2088 
  2089   Theory.axioms_of: theory -> (string * term) list
  2090   Theory.all_axioms_of: theory -> (string * term) list
  2091   PureThy.thms_of: theory -> (string * thm) list
  2092   PureThy.all_thms_of: theory -> (string * thm) list
  2093 
  2094 * Pure: print_tac now outputs the goal through the trace channel.
  2095 
  2096 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2097 Reference Toplevel.debug (default false) controls detailed printing
  2098 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2099 controls execution profiling -- set to 1 for time and 2 for space
  2100 (both increase the runtime).
  2101 
  2102 * Isar session: The initial use of ROOT.ML is now always timed,
  2103 i.e. the log will show the actual process times, in contrast to the
  2104 elapsed wall-clock time that the outer shell wrapper produces.
  2105 
  2106 * Simplifier: improved handling of bound variables (nameless
  2107 representation, avoid allocating new strings).  Simprocs that invoke
  2108 the Simplifier recursively should use Simplifier.inherit_bounds to
  2109 avoid local name clashes.  Failure to do so produces warnings
  2110 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2111 for further details.
  2112 
  2113 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2114 bindings for all theorems stored within a given theory; this may help
  2115 in porting non-Isar theories to Isar ones, while keeping ML proof
  2116 scripts for the time being.
  2117 
  2118 * ML operator HTML.with_charset specifies the charset begin used for
  2119 generated HTML files.  For example:
  2120 
  2121   HTML.with_charset "utf-8" use_thy "Hebrew";
  2122   HTML.with_charset "utf-8" use_thy "Chinese";
  2123 
  2124 
  2125 *** System ***
  2126 
  2127 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2128 isabelle, isatool etc.).
  2129 
  2130 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2131 isatool doc, isatool mkdir, display_drafts etc.).
  2132 
  2133 * isatool usedir: option -f allows specification of the ML file to be
  2134 used by Isabelle; default is ROOT.ML.
  2135 
  2136 * New isatool version outputs the version identifier of the Isabelle
  2137 distribution being used.
  2138 
  2139 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2140 (containing Boolean satisfiability problems) into Isabelle/HOL
  2141 theories.
  2142 
  2143 
  2144 
  2145 New in Isabelle2004 (April 2004)
  2146 --------------------------------
  2147 
  2148 *** General ***
  2149 
  2150 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2151   Replaces linorder.ML.
  2152 
  2153 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2154   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2155   (\<a>...\<z>), are now considered normal letters, and can therefore
  2156   be used anywhere where an ASCII letter (a...zA...Z) has until
  2157   now. COMPATIBILITY: This obviously changes the parsing of some
  2158   terms, especially where a symbol has been used as a binder, say
  2159   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2160   as an identifier.  Fix it by inserting a space around former
  2161   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2162   existing theory and ML files.
  2163 
  2164 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2165 
  2166 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2167   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2168   a normal (but invisible) letter. For multiple letter subscripts repeat
  2169   \<^isub> like this: x\<^isub>1\<^isub>2.
  2170 
  2171 * Pure: There are now sub-/superscripts that can span more than one
  2172   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2173   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2174   superscript. The new control characters are not identifier parts.
  2175 
  2176 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2177   content of "..." to the latex file instead of \isacntrl... . The "..."
  2178   may consist of any printable characters excluding the end bracket >.
  2179 
  2180 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2181   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2182   declare constants "final", which prevents their being given a definition
  2183   later.  It is useful for constants whose behaviour is fixed axiomatically
  2184   rather than definitionally, such as the meta-logic connectives.
  2185 
  2186 * Pure: 'instance' now handles general arities with general sorts
  2187   (i.e. intersections of classes),
  2188 
  2189 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2190   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2191   It can be changed to alter the colors/layout of generated pages.
  2192 
  2193 
  2194 *** Isar ***
  2195 
  2196 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2197   cut_tac, subgoal_tac and thin_tac:
  2198   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2199     locales are no longer forced to write Isar proof scripts.
  2200     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2201     emulations.
  2202   - INCOMPATIBILITY: names of variables to be instantiated may no
  2203     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2204     This is consistent with the instantiation attribute "where".
  2205 
  2206 * Attributes "where" and "of":
  2207   - Now take type variables of instantiated theorem into account when reading
  2208     the instantiation string.  This fixes a bug that caused instantiated
  2209     theorems to have too special types in some circumstances.
  2210   - "where" permits explicit instantiations of type variables.
  2211 
  2212 * Calculation commands "moreover" and "also" no longer interfere with
  2213   current facts ("this"), admitting arbitrary combinations with "then"
  2214   and derived forms.
  2215 
  2216 * Locales:
  2217   - Goal statements involving the context element "includes" no longer
  2218     generate theorems with internal delta predicates (those ending on
  2219     "_axioms") in the premise.
  2220     Resolve particular premise with <locale>.intro to obtain old form.
  2221   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2222     specification and "includes" elements in goal statement.
  2223   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2224     [intro?] and [elim?] (respectively) by default.
  2225   - Experimental command for instantiation of locales in proof contexts:
  2226         instantiate <label>[<attrs>]: <loc>
  2227     Instantiates locale <loc> and adds all its theorems to the current context
  2228     taking into account their attributes.  Label and attrs are optional
  2229     modifiers, like in theorem declarations.  If present, names of
  2230     instantiated theorems are qualified with <label>, and the attributes
  2231     <attrs> are applied after any attributes these theorems might have already.
  2232       If the locale has assumptions, a chained fact of the form
  2233     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2234     are derived.  The command does not support old-style locales declared
  2235     with "locale (open)".
  2236       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2237 
  2238 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2239   (Isar) contexts.
  2240 
  2241 
  2242 *** HOL ***
  2243 
  2244 * Proof import: new image HOL4 contains the imported library from
  2245   the HOL4 system with about 2500 theorems. It is imported by
  2246   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2247   can be used like any other Isabelle image.  See
  2248   HOL/Import/HOL/README for more information.
  2249 
  2250 * Simplifier:
  2251   - Much improved handling of linear and partial orders.
  2252     Reasoners for linear and partial orders are set up for type classes
  2253     "linorder" and "order" respectively, and are added to the default simpset
  2254     as solvers.  This means that the simplifier can build transitivity chains
  2255     to solve goals from the assumptions.
  2256   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2257     of blast or auto after simplification become unnecessary because the goal
  2258     is solved by simplification already.
  2259 
  2260 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2261     all proved in axiomatic type classes for semirings, rings and fields.
  2262 
  2263 * Numerics:
  2264   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2265     now formalized using the Ring_and_Field theory mentioned above.
  2266   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2267     than before, because now they are set up once in a generic manner.
  2268   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2269     Look for the general versions in Ring_and_Field (and Power if they concern
  2270     exponentiation).
  2271 
  2272 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2273 
  2274 * Records:
  2275   - Record types are now by default printed with their type abbreviation
  2276     instead of the list of all field types. This can be configured via
  2277     the reference "print_record_type_abbr".
  2278   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2279     (not enabled by default).
  2280   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2281     EX x. x = sel r to True (not enabled by default).
  2282   - Tactic "record_split_simp_tac" to split and simplify records added.
  2283 
  2284 * 'specification' command added, allowing for definition by
  2285   specification.  There is also an 'ax_specification' command that
  2286   introduces the new constants axiomatically.
  2287 
  2288 * arith(_tac) is now able to generate counterexamples for reals as well.
  2289 
  2290 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2291 
  2292 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2293   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2294 
  2295 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2296   matrix theory to linear programming.
  2297 
  2298 * Unions and Intersections:
  2299   The latex output syntax of UN and INT has been changed
  2300   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2301   i.e. the index formulae has become a subscript.
  2302   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2303 
  2304 * Unions and Intersections over Intervals:
  2305   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2306   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2307   like in normal math, and corresponding versions for < and for intersection.
  2308 
  2309 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2310   lexicographic dictonary ordering has been added as "lexord".
  2311 
  2312 * ML: the legacy theory structures Int and List have been removed. They had
  2313   conflicted with ML Basis Library structures having the same names.
  2314 
  2315 * 'refute' command added to search for (finite) countermodels.  Only works
  2316   for a fragment of HOL.  The installation of an external SAT solver is
  2317   highly recommended.  See "HOL/Refute.thy" for details.
  2318 
  2319 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2320   formulae under an assignment of free variables to random values.
  2321   In contrast to 'refute', it can deal with inductive datatypes,
  2322   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2323   for examples.
  2324 
  2325 
  2326 *** HOLCF ***
  2327 
  2328 * Streams now come with concatenation and are part of the HOLCF image
  2329 
  2330 
  2331 
  2332 New in Isabelle2003 (May 2003)
  2333 ------------------------------
  2334 
  2335 *** General ***
  2336 
  2337 * Provers/simplifier:
  2338 
  2339   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2340     Assumptions are now subject to complete mutual simplification,
  2341     not just from left to right. The simplifier now preserves
  2342     the order of assumptions.
  2343 
  2344     Potential INCOMPATIBILITY:
  2345 
  2346     -- simp sometimes diverges where the old version did
  2347        not, e.g. invoking simp on the goal
  2348 
  2349         [| P (f x); y = x; f x = f y |] ==> Q
  2350 
  2351        now gives rise to the infinite reduction sequence
  2352 
  2353         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2354 
  2355        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2356        kind of problem.
  2357 
  2358     -- Tactics combining classical reasoner and simplification (such as auto)
  2359        are also affected by this change, because many of them rely on
  2360        simp. They may sometimes diverge as well or yield a different numbers
  2361        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2362        in case of problems. Sometimes subsequent calls to the classical
  2363        reasoner will fail because a preceeding call to the simplifier too
  2364        eagerly simplified the goal, e.g. deleted redundant premises.
  2365 
  2366   - The simplifier trace now shows the names of the applied rewrite rules
  2367 
  2368   - You can limit the number of recursive invocations of the simplifier
  2369     during conditional rewriting (where the simplifie tries to solve the
  2370     conditions before applying the rewrite rule):
  2371     ML "simp_depth_limit := n"
  2372     where n is an integer. Thus you can force termination where previously
  2373     the simplifier would diverge.
  2374 
  2375   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2376 
  2377   - No longer aborts on failed congruence proof.  Instead, the
  2378     congruence is ignored.
  2379 
  2380 * Pure: New generic framework for extracting programs from constructive
  2381   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2382   as HOL/Extraction for some case studies.
  2383 
  2384 * Pure: The main goal of the proof state is no longer shown by default, only
  2385 the subgoals. This behaviour is controlled by a new flag.
  2386    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2387 (ML: Proof.show_main_goal).
  2388 
  2389 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2390 rules whose conclusion matches subgoal 1:
  2391       PG menu: Isabelle/Isar -> Show me -> matching rules
  2392 The rules are ordered by how closely they match the subgoal.
  2393 In particular, rules that solve a subgoal outright are displayed first
  2394 (or rather last, the way they are printed).
  2395 (ML: ProofGeneral.print_intros())
  2396 
  2397 * Pure: New flag trace_unify_fail causes unification to print
  2398 diagnostic information (PG: in trace buffer) when it fails. This is
  2399 useful for figuring out why single step proofs like rule, erule or
  2400 assumption failed.
  2401 
  2402 * Pure: Locale specifications now produce predicate definitions
  2403 according to the body of text (covering assumptions modulo local
  2404 definitions); predicate "loc_axioms" covers newly introduced text,
  2405 while "loc" is cumulative wrt. all included locale expressions; the
  2406 latter view is presented only on export into the global theory
  2407 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2408 on the old view without predicates;
  2409 
  2410 * Pure: predefined locales "var" and "struct" are useful for sharing
  2411 parameters (as in CASL, for example); just specify something like
  2412 ``var x + var y + struct M'' as import;
  2413 
  2414 * Pure: improved thms_containing: proper indexing of facts instead of
  2415 raw theorems; check validity of results wrt. current name space;
  2416 include local facts of proof configuration (also covers active
  2417 locales), cover fixed variables in index; may use "_" in term
  2418 specification; an optional limit for the number of printed facts may
  2419 be given (the default is 40);
  2420 
  2421 * Pure: disallow duplicate fact bindings within new-style theory files
  2422 (batch-mode only);
  2423 
  2424 * Provers: improved induct method: assumptions introduced by case
  2425 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2426 the goal statement); "foo" still refers to all facts collectively;
  2427 
  2428 * Provers: the function blast.overloaded has been removed: all constants
  2429 are regarded as potentially overloaded, which improves robustness in exchange
  2430 for slight decrease in efficiency;
  2431 
  2432 * Provers/linorder: New generic prover for transitivity reasoning over
  2433 linear orders.  Note: this prover is not efficient!
  2434 
  2435 * Isar: preview of problems to finish 'show' now produce an error
  2436 rather than just a warning (in interactive mode);
  2437 
  2438 
  2439 *** HOL ***
  2440 
  2441 * arith(_tac)
  2442 
  2443  - Produces a counter example if it cannot prove a goal.
  2444    Note that the counter example may be spurious if the goal is not a formula
  2445    of quantifier-free linear arithmetic.
  2446    In ProofGeneral the counter example appears in the trace buffer.
  2447 
  2448  - Knows about div k and mod k where k is a numeral of type nat or int.
  2449 
  2450  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2451    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2452    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2453 
  2454 * simp's arithmetic capabilities have been enhanced a bit: it now
  2455 takes ~= in premises into account (by performing a case split);
  2456 
  2457 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2458 are distributed over a sum of terms;
  2459 
  2460 * New tactic "trans_tac" and method "trans" instantiate
  2461 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2462 "<=", "<" and "=").
  2463 
  2464 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2465 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2466 
  2467 * 'typedef' command has new option "open" to suppress the set
  2468 definition;
  2469 
  2470 * functions Min and Max on finite sets have been introduced (theory
  2471 Finite_Set);
  2472 
  2473 * attribute [symmetric] now works for relations as well; it turns
  2474 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2475 
  2476 * induct over a !!-quantified statement (say !!x1..xn):
  2477   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2478 
  2479 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2480 %x. None. Warning: empty_def now refers to the previously hidden definition
  2481 of the empty set.
  2482 
  2483 * Algebra: formalization of classical algebra.  Intended as base for
  2484 any algebraic development in Isabelle.  Currently covers group theory
  2485 (up to Sylow's theorem) and ring theory (Universal Property of
  2486 Univariate Polynomials).  Contributions welcome;
  2487 
  2488 * GroupTheory: deleted, since its material has been moved to Algebra;
  2489 
  2490 * Complex: new directory of the complex numbers with numeric constants,
  2491 nonstandard complex numbers, and some complex analysis, standard and
  2492 nonstandard (Jacques Fleuriot);
  2493 
  2494 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2495 
  2496 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2497 Fleuriot);
  2498 
  2499 * Real/HahnBanach: updated and adapted to locales;
  2500 
  2501 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2502 Gray and Kramer);
  2503 
  2504 * UNITY: added the Meier-Sanders theory of progress sets;
  2505 
  2506 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2507 as abstract algorithms, instantiated to the JVM;
  2508 
  2509 * Bali: Java source language formalization. Type system, operational
  2510 semantics, axiomatic semantics. Supported language features:
  2511 classes, interfaces, objects,virtual methods, static methods,
  2512 static/instance fields, arrays, access modifiers, definite
  2513 assignment, exceptions.
  2514 
  2515 
  2516 *** ZF ***
  2517 
  2518 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2519 universe, etc.);
  2520 
  2521 * Main ZF: virtually all theories converted to new-style format;
  2522 
  2523 
  2524 *** ML ***
  2525 
  2526 * Pure: Tactic.prove provides sane interface for internal proofs;
  2527 omits the infamous "standard" operation, so this is more appropriate
  2528 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2529 
  2530 * Pure: improved error reporting of simprocs;
  2531 
  2532 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2533 up simprocs;
  2534 
  2535 
  2536 *** Document preparation ***
  2537 
  2538 * uses \par instead of \\ for line breaks in theory text. This may
  2539 shift some page breaks in large documents. To get the old behaviour
  2540 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2541 
  2542 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2543 other packages
  2544 
  2545 * \<euro> now needs package babel/greek instead of marvosym (which
  2546 broke \Rightarrow)
  2547 
  2548 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2549 textcomp package)
  2550 
  2551 
  2552 
  2553 New in Isabelle2002 (March 2002)
  2554 --------------------------------
  2555 
  2556 *** Document preparation ***
  2557 
  2558 * greatly simplified document preparation setup, including more
  2559 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2560 instructive isatool mkdir; users should basically be able to get
  2561 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2562 users may run a separate document processing stage manually like this:
  2563 "isatool usedir -D output HOL Test && isatool document Test/output";
  2564 
  2565 * theory dependency graph may now be incorporated into documents;
  2566 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2567 with \includegraphics of LaTeX;
  2568 
  2569 * proper spacing of consecutive markup elements, especially text
  2570 blocks after section headings;
  2571 
  2572 * support bold style (for single symbols only), input syntax is like
  2573 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2574 
  2575 * \<bullet> is now output as bold \cdot by default, which looks much
  2576 better in printed text;
  2577 
  2578 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2579 note that these symbols are currently unavailable in Proof General /
  2580 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2581 
  2582 * isatool latex no longer depends on changed TEXINPUTS, instead
  2583 isatool document copies the Isabelle style files to the target
  2584 location;
  2585 
  2586 
  2587 *** Isar ***
  2588 
  2589 * Pure/Provers: improved proof by cases and induction;
  2590   - 'case' command admits impromptu naming of parameters (such as
  2591     "case (Suc n)");
  2592   - 'induct' method divinates rule instantiation from the inductive
  2593     claim; no longer requires excessive ?P bindings for proper
  2594     instantiation of cases;
  2595   - 'induct' method properly enumerates all possibilities of set/type
  2596     rules; as a consequence facts may be also passed through *type*
  2597     rules without further ado;
  2598   - 'induct' method now derives symbolic cases from the *rulified*
  2599     rule (before it used to rulify cases stemming from the internal
  2600     atomized version); this means that the context of a non-atomic
  2601     statement becomes is included in the hypothesis, avoiding the
  2602     slightly cumbersome show "PROP ?case" form;
  2603   - 'induct' may now use elim-style induction rules without chaining
  2604     facts, using ``missing'' premises from the goal state; this allows
  2605     rules stemming from inductive sets to be applied in unstructured
  2606     scripts, while still benefitting from proper handling of non-atomic
  2607     statements; NB: major inductive premises need to be put first, all
  2608     the rest of the goal is passed through the induction;
  2609   - 'induct' proper support for mutual induction involving non-atomic
  2610     rule statements (uses the new concept of simultaneous goals, see
  2611     below);
  2612   - append all possible rule selections, but only use the first
  2613     success (no backtracking);
  2614   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2615   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2616   - added 'print_induct_rules' (covered by help item in recent Proof
  2617     General versions);
  2618   - moved induct/cases attributes to Pure, methods to Provers;
  2619   - generic method setup instantiated for FOL and HOL;
  2620 
  2621 * Pure: support multiple simultaneous goal statements, for example
  2622 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2623 meta-level mechanism, this acts as if several individual goals had
  2624 been stated separately; in particular common proof methods need to be
  2625 repeated in order to cover all claims; note that a single elimination
  2626 step is *not* sufficient to establish the two conjunctions, so this
  2627 fails:
  2628 
  2629   assume "A & B" then have A and B ..   (*".." fails*)
  2630 
  2631 better use "obtain" in situations as above; alternative refer to
  2632 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2633 
  2634 * Pure: proper integration with ``locales''; unlike the original
  2635 version by Florian Kammller, Isar locales package high-level proof
  2636 contexts rather than raw logical ones (e.g. we admit to include
  2637 attributes everywhere); operations on locales include merge and
  2638 rename; support for implicit arguments (``structures''); simultaneous
  2639 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2640 some examples;
  2641 
  2642 * Pure: the following commands have been ``localized'', supporting a
  2643 target locale specification "(in name)": 'lemma', 'theorem',
  2644 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2645 stored both within the locale and at the theory level (exported and
  2646 qualified by the locale name);
  2647 
  2648 * Pure: theory goals may now be specified in ``long'' form, with
  2649 ad-hoc contexts consisting of arbitrary locale elements. for example
  2650 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2651 definitions may be given, too); the result is a meta-level rule with
  2652 the context elements being discharged in the obvious way;
  2653 
  2654 * Pure: new proof command 'using' allows to augment currently used
  2655 facts after a goal statement ('using' is syntactically analogous to
  2656 'apply', but acts on the goal's facts only); this allows chained facts
  2657 to be separated into parts given before and after a claim, as in
  2658 ``from a and b have C using d and e <proof>'';
  2659 
  2660 * Pure: renamed "antecedent" case to "rule_context";
  2661 
  2662 * Pure: new 'judgment' command records explicit information about the
  2663 object-logic embedding (used by several tools internally); no longer
  2664 use hard-wired "Trueprop";
  2665 
  2666 * Pure: added 'corollary' command;
  2667 
  2668 * Pure: fixed 'token_translation' command;
  2669 
  2670 * Pure: removed obsolete 'exported' attribute;
  2671 
  2672 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2673 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2674 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2675 
  2676 * Pure: method 'atomize' presents local goal premises as object-level
  2677 statements (atomic meta-level propositions); setup controlled via
  2678 rewrite rules declarations of 'atomize' attribute; example
  2679 application: 'induct' method with proper rule statements in improper
  2680 proof *scripts*;
  2681 
  2682 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2683 now consider the syntactic context of assumptions, giving a better
  2684 chance to get type-inference of the arguments right (this is
  2685 especially important for locales);
  2686 
  2687 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2688 mode;
  2689 
  2690 * Pure/obtain: the formal conclusion "thesis", being marked as
  2691 ``internal'', may no longer be reference directly in the text;
  2692 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2693 situations;
  2694 
  2695 * Pure: generic 'sym' attribute which declares a rule both as pure
  2696 'elim?' and for the 'symmetric' operation;
  2697 
  2698 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2699 text; the fixed correlation with particular command syntax has been
  2700 discontinued;
  2701 
  2702 * Pure: new method 'rules' is particularly well-suited for proof
  2703 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2704 but often produces more compact proof terms with less detours;
  2705 
  2706 * Pure/Provers/classical: simplified integration with pure rule
  2707 attributes and methods; the classical "intro?/elim?/dest?"
  2708 declarations coincide with the pure ones; the "rule" method no longer
  2709 includes classically swapped intros; "intro" and "elim" methods no
  2710 longer pick rules from the context; also got rid of ML declarations
  2711 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2712 INCOMPATIBILITY;
  2713 
  2714 * Provers/classical: attribute 'swapped' produces classical inversions
  2715 of introduction rules;
  2716 
  2717 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2718 rules instead of full simplifier context; 'iff' attribute handles
  2719 conditional rules;
  2720 
  2721 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2722 
  2723 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2724 "(permissive)" option to recover old behavior;
  2725 
  2726 * HOL: 'inductive' no longer features separate (collective) attributes
  2727 for 'intros' (was found too confusing);
  2728 
  2729 * HOL: properly declared induction rules less_induct and
  2730 wf_induct_rule;
  2731 
  2732 
  2733 *** HOL ***
  2734 
  2735 * HOL: moved over to sane numeral syntax; the new policy is as
  2736 follows:
  2737 
  2738   - 0 and 1 are polymorphic constants, which are defined on any
  2739   numeric type (nat, int, real etc.);
  2740 
  2741   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2742   binary representation internally;
  2743 
  2744   - type nat has special constructor Suc, and generally prefers Suc 0
  2745   over 1::nat and Suc (Suc 0) over 2::nat;
  2746 
  2747 This change may cause significant problems of INCOMPATIBILITY; here
  2748 are some hints on converting existing sources:
  2749 
  2750   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2751   entities, so expressions involving "-" (unary or binary minus) need
  2752   to be spaced properly;
  2753 
  2754   - existing occurrences of "1" may need to be constraint "1::nat" or
  2755   even replaced by Suc 0; similar for old "2";
  2756 
  2757   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2758 
  2759   - remove all special provisions on numerals in proofs;
  2760 
  2761 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2762 representation (depends on bin_arith_simps in the default context);
  2763 
  2764 * HOL: symbolic syntax for x^2 (numeral 2);
  2765 
  2766 * HOL: the class of all HOL types is now called "type" rather than
  2767 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2768 in axclass/classes, instance/arities, and (usually rare) occurrences
  2769 in typings (of consts etc.); internally the class is called
  2770 "HOL.type", ML programs should refer to HOLogic.typeS;
  2771 
  2772 * HOL/record package improvements:
  2773   - new derived operations "fields" to build a partial record section,
  2774     "extend" to promote a fixed record to a record scheme, and
  2775     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2776     declared as simp by default;
  2777   - shared operations ("more", "fields", etc.) now need to be always
  2778     qualified) --- potential INCOMPATIBILITY;
  2779   - removed "make_scheme" operations (use "make" with "extend") --
  2780     INCOMPATIBILITY;
  2781   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2782   - provides cases/induct rules for use with corresponding Isar
  2783     methods (for concrete records, record schemes, concrete more
  2784     parts, and schematic more parts -- in that order);
  2785   - internal definitions directly based on a light-weight abstract
  2786     theory of product types over typedef rather than datatype;
  2787 
  2788 * HOL: generic code generator for generating executable ML code from
  2789 specifications; specific support for HOL constructs such as inductive
  2790 datatypes and sets, as well as recursive functions; can be invoked
  2791 via 'generate_code' theory section;
  2792 
  2793 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2794 
  2795 * HOL: consolidated and renamed several theories.  In particular:
  2796         Ord.thy has been absorbed into HOL.thy
  2797         String.thy has been absorbed into List.thy
  2798 
  2799 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2800 (beware of argument permutation!);
  2801 
  2802 * HOL: linorder_less_split superseded by linorder_cases;
  2803 
  2804 * HOL/List: "nodups" renamed to "distinct";
  2805 
  2806 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2807 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2808   - Ex_def has changed, now need to use some_eq_ex
  2809 
  2810 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2811 in this (rare) case use:
  2812 
  2813   delSWrapper "split_all_tac"
  2814   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2815 
  2816 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2817 MAY FAIL;
  2818 
  2819 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2820 Isabelle's type classes, ^ on functions and relations has too general
  2821 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2822 necessary to attach explicit type constraints;
  2823 
  2824 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2825 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2826 renamed accordingly (eg "compI" -> "rel_compI").
  2827 
  2828 * HOL: syntax translations now work properly with numerals and records
  2829 expressions;
  2830 
  2831 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2832 of "lam" -- INCOMPATIBILITY;
  2833 
  2834 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2835 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2836 renamed "Product_Type.unit";
  2837 
  2838 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2839 
  2840 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2841 the "cases" method);
  2842 
  2843 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2844 Florian Kammller);
  2845 
  2846 * HOL/IMP: updated and converted to new-style theory format; several
  2847 parts turned into readable document, with proper Isar proof texts and
  2848 some explanations (by Gerwin Klein);
  2849 
  2850 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2851 
  2852 * HOL-Hyperreal is now a logic image;
  2853 
  2854 
  2855 *** HOLCF ***
  2856 
  2857 * Isar: consts/constdefs supports mixfix syntax for continuous
  2858 operations;
  2859 
  2860 * Isar: domain package adapted to new-style theory format, e.g. see
  2861 HOLCF/ex/Dnat.thy;
  2862 
  2863 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2864 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2865 lift.induct_tac, always use UU instead of Undef;
  2866 
  2867 * HOLCF/IMP: updated and converted to new-style theory;
  2868 
  2869 
  2870 *** ZF ***
  2871 
  2872 * Isar: proper integration of logic-specific tools and packages,
  2873 including theory commands '(co)inductive', '(co)datatype',
  2874 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2875 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2876 
  2877 * theory Main no longer includes AC; for the Axiom of Choice, base
  2878 your theory on Main_ZFC;
  2879 
  2880 * the integer library now covers quotients and remainders, with many
  2881 laws relating division to addition, multiplication, etc.;
  2882 
  2883 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2884 typeless version of the formalism;
  2885 
  2886 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2887 format;
  2888 
  2889 * ZF/Induct: new directory for examples of inductive definitions,
  2890 including theory Multiset for multiset orderings; converted to
  2891 new-style theory format;
  2892 
  2893 * ZF: many new theorems about lists, ordinals, etc.;
  2894 
  2895 
  2896 *** General ***
  2897 
  2898 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2899 variable proof controls level of detail: 0 = no proofs (only oracle
  2900 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2901 also ref manual for further ML interfaces;
  2902 
  2903 * Pure/axclass: removed obsolete ML interface
  2904 goal_subclass/goal_arity;
  2905 
  2906 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2907 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2908 separate tokens, so expressions involving minus need to be spaced
  2909 properly;
  2910 
  2911 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2912 rather than "infixl" or "infixr";
  2913 
  2914 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2915 sort constraint specifications in type inference; e.g. "x::_::foo"
  2916 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2917 type variable);
  2918 
  2919 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2920 control output of nested => (types); the default behavior is
  2921 "type_brackets";
  2922 
  2923 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2924 tokens into AST constants;
  2925 
  2926 * Pure/syntax: prefer later declarations of translations and print
  2927 translation functions; potential INCOMPATIBILITY: need to reverse
  2928 multiple declarations for same syntax element constant;
  2929 
  2930 * Pure/show_hyps reset by default (in accordance to existing Isar
  2931 practice);
  2932 
  2933 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2934 addSafter;
  2935 
  2936 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2937 as well;
  2938 
  2939 * system: tested support for MacOS X; should be able to get Isabelle +
  2940 Proof General to work in a plain Terminal after installing Poly/ML
  2941 (e.g. from the Isabelle distribution area) and GNU bash alone
  2942 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2943 support requires further installations, e.g. from
  2944 http://fink.sourceforge.net/);
  2945 
  2946 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2947 
  2948 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2949 of 40 MB), cf. ML_OPTIONS;
  2950 
  2951 * system: Proof General keywords specification is now part of the
  2952 Isabelle distribution (see etc/isar-keywords.el);
  2953 
  2954 * system: support for persistent Proof General sessions (refrain from
  2955 outdating all loaded theories on startup); user may create writable
  2956 logic images like this: ``isabelle -q HOL Test'';
  2957 
  2958 * system: smart selection of Isabelle process versus Isabelle
  2959 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2960 run both "isabelle" and "Isabelle" even if file names are badly
  2961 damaged (executable inspects the case of the first letter of its own
  2962 name); added separate "isabelle-process" and "isabelle-interface";
  2963 
  2964 * system: refrain from any attempt at filtering input streams; no
  2965 longer support ``8bit'' encoding of old isabelle font, instead proper
  2966 iso-latin characters may now be used; the related isatools
  2967 "symbolinput" and "nonascii" have disappeared as well;
  2968 
  2969 * system: removed old "xterm" interface (the print modes "xterm" and
  2970 "xterm_color" are still available for direct use in a suitable
  2971 terminal);
  2972 
  2973 
  2974 
  2975 New in Isabelle99-2 (February 2001)
  2976 -----------------------------------
  2977 
  2978 *** Overview of INCOMPATIBILITIES ***
  2979 
  2980 * HOL: please note that theories in the Library and elsewhere often use the
  2981 new-style (Isar) format; to refer to their theorems in an ML script you must
  2982 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2983 
  2984 * HOL: inductive package no longer splits induction rule aggressively,
  2985 but only as far as specified by the introductions given; the old
  2986 format may be recovered via ML function complete_split_rule or attribute
  2987 'split_rule (complete)';
  2988 
  2989 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2990 gfp_Tarski to gfp_unfold;
  2991 
  2992 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2993 
  2994 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2995 relation); infix "^^" has been renamed "``"; infix "``" has been
  2996 renamed "`"; "univalent" has been renamed "single_valued";
  2997 
  2998 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2999 operation;
  3000 
  3001 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3002 
  3003 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3004 
  3005 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3006 consequence, it is no longer monotonic wrt. the local goal context
  3007 (which is now passed through the inductive cases);
  3008 
  3009 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3010 \<gg> to \<ggreater>;
  3011 
  3012 
  3013 *** Document preparation ***
  3014 
  3015 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3016 available: are "it" for near math-mode best-style output, "sl" for
  3017 slanted text style, and "tt" for plain type-writer; if no
  3018 \isabellestyle command is given, output is according to slanted
  3019 type-writer);
  3020 
  3021 * support sub/super scripts (for single symbols only), input syntax is
  3022 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3023 
  3024 * some more standard symbols; see Appendix A of the system manual for
  3025 the complete list of symbols defined in isabellesym.sty;
  3026 
  3027 * improved isabelle style files; more abstract symbol implementation
  3028 (should now use \isamath{...} and \isatext{...} in custom symbol
  3029 definitions);
  3030 
  3031 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3032 state; Note that presentation of goal states does not conform to
  3033 actual human-readable proof documents.  Please do not include goal
  3034 states into document output unless you really know what you are doing!
  3035 
  3036 * proper indentation of antiquoted output with proportional LaTeX
  3037 fonts;
  3038 
  3039 * no_document ML operator temporarily disables LaTeX document
  3040 generation;
  3041 
  3042 * isatool unsymbolize tunes sources for plain ASCII communication;
  3043 
  3044 
  3045 *** Isar ***
  3046 
  3047 * Pure: Isar now suffers initial goal statements to contain unbound
  3048 schematic variables (this does not conform to actual readable proof
  3049 documents, due to unpredictable outcome and non-compositional proof
  3050 checking); users who know what they are doing may use schematic goals
  3051 for Prolog-style synthesis of proven results;
  3052 
  3053 * Pure: assumption method (an implicit finishing) now handles actual
  3054 rules as well;
  3055 
  3056 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3057 initial goal, declare "that" only as Pure intro (only for single
  3058 steps); the "that" rule assumption may now be involved in implicit
  3059 finishing, thus ".." becomes a feasible for trivial obtains;
  3060 
  3061 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3062 instance proofs may be performed by "..";
  3063 
  3064 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3065 statements as well;
  3066 
  3067 * Pure: more robust selection of calculational rules;
  3068 
  3069 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3070 rule (as well as the assumption rule);
  3071 
  3072 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3073 lemmas, using the graph browser tool;
  3074 
  3075 * Pure: predict failure of "show" in interactive mode;
  3076 
  3077 * Pure: 'thms_containing' now takes actual terms as arguments;
  3078 
  3079 * HOL: improved method 'induct' --- now handles non-atomic goals
  3080 (potential INCOMPATIBILITY); tuned error handling;
  3081 
  3082 * HOL: cases and induct rules now provide explicit hints about the
  3083 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3084 any remaining facts are inserted into the goal verbatim;
  3085 
  3086 * HOL: local contexts (aka cases) may now contain term bindings as
  3087 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3088 the result to be shown in each case;
  3089 
  3090 * HOL: added 'recdef_tc' command;
  3091 
  3092 * isatool convert assists in eliminating legacy ML scripts;
  3093 
  3094 
  3095 *** HOL ***
  3096 
  3097 * HOL/Library: a collection of generic theories to be used together
  3098 with main HOL; the theory loader path already includes this directory
  3099 by default; the following existing theories have been moved here:
  3100 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3101 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3102 
  3103 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3104 modelling and verification task performed in Isabelle/HOL +
  3105 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3106 
  3107 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3108 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3109 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3110 'domain', this makes the theory consistent with mathematical
  3111 literature;
  3112 
  3113 * HOL basics: added overloaded operations "inverse" and "divide"
  3114 (infix "/"), syntax for generic "abs" operation, generic summation
  3115 operator \<Sum>;
  3116 
  3117 * HOL/typedef: simplified package, provide more useful rules (see also
  3118 HOL/subset.thy);
  3119 
  3120 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3121 now expressed as a proper nested rule (old-style tactic scripts may
  3122 require atomize_strip_tac to cope with non-atomic premises);
  3123 
  3124 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3125 to "split_conv" (old name still available for compatibility);
  3126 
  3127 * HOL: improved concrete syntax for strings (e.g. allows translation
  3128 rules with string literals);
  3129 
  3130 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3131  and Fleuriot's mechanization of analysis, including the transcendental
  3132  functions for the reals;
  3133 
  3134 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3135 
  3136 
  3137 *** CTT ***
  3138 
  3139 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3140 "lam" is displayed as TWO lambda-symbols
  3141 
  3142 * CTT: theory Main now available, containing everything (that is, Bool
  3143 and Arith);
  3144 
  3145 
  3146 *** General ***
  3147 
  3148 * Pure: the Simplifier has been implemented properly as a derived rule
  3149 outside of the actual kernel (at last!); the overall performance
  3150 penalty in practical applications is about 50%, while reliability of
  3151 the Isabelle inference kernel has been greatly improved;
  3152 
  3153 * print modes "brackets" and "no_brackets" control output of nested =>
  3154 (types) and ==> (props); the default behaviour is "brackets";
  3155 
  3156 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3157 as assumptions as well;
  3158 
  3159 * system: support Poly/ML 4.0;
  3160 
  3161 * system: isatool install handles KDE version 1 or 2;
  3162 
  3163 
  3164 
  3165 New in Isabelle99-1 (October 2000)
  3166 ----------------------------------
  3167 
  3168 *** Overview of INCOMPATIBILITIES ***
  3169 
  3170 * HOL: simplification of natural numbers is much changed; to partly
  3171 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3172 issue the following ML commands:
  3173 
  3174   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3175   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3176 
  3177 * HOL: simplification no longer dives into case-expressions; this is
  3178 controlled by "t.weak_case_cong" for each datatype t;
  3179 
  3180 * HOL: nat_less_induct renamed to less_induct;
  3181 
  3182 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3183 fixsome to patch .thy and .ML sources automatically;
  3184 
  3185   select_equality  -> some_equality
  3186   select_eq_Ex     -> some_eq_ex
  3187   selectI2EX       -> someI2_ex
  3188   selectI2         -> someI2
  3189   selectI          -> someI
  3190   select1_equality -> some1_equality
  3191   Eps_sym_eq       -> some_sym_eq_trivial
  3192   Eps_eq           -> some_eq_trivial
  3193 
  3194 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3195 
  3196 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3197 instead);
  3198 
  3199 * HOL: the recursion equations generated by 'recdef' are now called
  3200 f.simps instead of f.rules;
  3201 
  3202 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3203 
  3204 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3205 sometimes be needed;
  3206 
  3207 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3208 
  3209 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3210 
  3211 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3212 product is now "<*>" instead of "Times"; the lexicographic product is
  3213 now "<*lex*>" instead of "**";
  3214 
  3215 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3216 of main HOL, but was unused); better use HOL's datatype package;
  3217 
  3218 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3219 the old syntax may be recovered as follows:
  3220 
  3221   syntax (symbols)
  3222     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3223       (infixl "\\<oplus>" 100)
  3224 
  3225 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3226 
  3227 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3228 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3229 internally;
  3230 
  3231 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3232 changed from A/r to A//r;
  3233 
  3234 * ZF: new treatment of arithmetic (nat & int) may break some old
  3235 proofs;
  3236 
  3237 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3238 rulify -> rule_format, elimify -> elim_format, ...);
  3239 
  3240 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3241 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3242 should have to change intro!! to intro? only); replaced "delrule" by
  3243 "rule del";
  3244 
  3245 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3246 
  3247 * Provers: strengthened force_tac by using new first_best_tac;
  3248 
  3249 * LaTeX document preparation: several changes of isabelle.sty (see
  3250 lib/texinputs);
  3251 
  3252 
  3253 *** Document preparation ***
  3254 
  3255 * formal comments (text blocks etc.) in new-style theories may now
  3256 contain antiquotations of thm/prop/term/typ/text to be presented
  3257 according to latex print mode; concrete syntax is like this:
  3258 @{term[show_types] "f(x) = a + x"};
  3259 
  3260 * isatool mkdir provides easy setup of Isabelle session directories,
  3261 including proper document sources;
  3262 
  3263 * generated LaTeX sources are now deleted after successful run
  3264 (isatool document -c); may retain a copy somewhere else via -D option
  3265 of isatool usedir;
  3266 
  3267 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3268 style files, achieving self-contained LaTeX sources and simplifying
  3269 LaTeX debugging;
  3270 
  3271 * old-style theories now produce (crude) LaTeX output as well;
  3272 
  3273 * browser info session directories are now self-contained (may be put
  3274 on WWW server seperately); improved graphs of nested sessions; removed
  3275 graph for 'all sessions';
  3276 
  3277 * several improvements in isabelle style files; \isabellestyle{it}
  3278 produces fake math mode output; \isamarkupheader is now \section by
  3279 default; see lib/texinputs/isabelle.sty etc.;
  3280 
  3281 
  3282 *** Isar ***
  3283 
  3284 * Isar/Pure: local results and corresponding term bindings are now
  3285 subject to Hindley-Milner polymorphism (similar to ML); this
  3286 accommodates incremental type-inference very nicely;
  3287 
  3288 * Isar/Pure: new derived language element 'obtain' supports
  3289 generalized existence reasoning;
  3290 
  3291 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3292 support accumulation of results, without applying any rules yet;
  3293 useful to collect intermediate results without explicit name
  3294 references, and for use with transitivity rules with more than 2
  3295 premises;
  3296 
  3297 * Isar/Pure: scalable support for case-analysis type proofs: new
  3298 'case' language element refers to local contexts symbolically, as
  3299 produced by certain proof methods; internally, case names are attached
  3300 to theorems as "tags";
  3301 
  3302 * Isar/Pure: theory command 'hide' removes declarations from
  3303 class/type/const name spaces;
  3304 
  3305 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3306 indicate potential overloading;
  3307 
  3308 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3309 
  3310 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3311 "{a,b,c}" instead of {a,b,c};
  3312 
  3313 * Isar/Pure now provides its own version of intro/elim/dest
  3314 attributes; useful for building new logics, but beware of confusion
  3315 with the version in Provers/classical;
  3316 
  3317 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3318 case name 'antecedent';
  3319 
  3320 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3321 to the current context is now done automatically);
  3322 
  3323 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3324 for definining proof methods in ML;
  3325 
  3326 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3327 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3328 most cases, one should have to change intro!! to intro? only);
  3329 replaced "delrule" by "rule del";
  3330 
  3331 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3332 'symmetric' attribute (the latter supercedes [RS sym]);
  3333 
  3334 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3335 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3336 well (including splits);
  3337 
  3338 * Isar/Provers: Simplifier and Classical methods now support all kind
  3339 of modifiers used in the past, including 'cong', 'iff', etc.
  3340 
  3341 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3342 of Simplifier and Classical reasoner);
  3343 
  3344 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3345 now support named cases; major packages (inductive, datatype, primrec,
  3346 recdef) support case names and properly name parameters;
  3347 
  3348 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3349 monotonicity conditions are extracted to be proven at end of
  3350 calculations;
  3351 
  3352 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3353 method anyway;
  3354 
  3355 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3356 split_if split_if_asm; datatype package provides theorems foo.splits =
  3357 foo.split foo.split_asm for each datatype;
  3358 
  3359 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3360 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3361 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3362 use "(cases (simplified))" method in proper proof texts);
  3363 
  3364 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3365 
  3366 * Isar: names of theorems etc. may be natural numbers as well;
  3367 
  3368 * Isar: 'pr' command: optional arguments for goals_limit and
  3369 ProofContext.prems_limit; no longer prints theory contexts, but only
  3370 proof states;
  3371 
  3372 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3373 additional print modes to be specified; e.g. "pr(latex)" will print
  3374 proof state according to the Isabelle LaTeX style;
  3375 
  3376 * Isar: improved support for emulating tactic scripts, including proof
  3377 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3378 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3379 (for HOL datatypes);
  3380 
  3381 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3382 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3383 'proof method scripts' have to be in depth-first order;
  3384 
  3385 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3386 
  3387 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3388 should instead use individual commands for printing items
  3389 (print_commands, print_methods etc.);
  3390 
  3391 * Isar: added 'nothing' --- the empty list of theorems;
  3392 
  3393 
  3394 *** HOL ***
  3395 
  3396 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3397 corresponding virtual machine and a specification of its bytecode
  3398 verifier and a lightweight bytecode verifier, including proofs of
  3399 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3400 Cornelia Pusch (see also the homepage of project Bali at
  3401 http://isabelle.in.tum.de/Bali/);
  3402 
  3403 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3404 Clemens Ballarin;
  3405 
  3406 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3407 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3408 Rasmussen;
  3409 
  3410 * HOL/Lattice: fundamental concepts of lattice theory and order
  3411 structures, including duals, properties of bounds versus algebraic
  3412 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3413 Theorem for complete lattices etc.; may also serve as a demonstration
  3414 for abstract algebraic reasoning using axiomatic type classes, and
  3415 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3416 
  3417 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3418 von Oheimb;
  3419 
  3420 * HOL/IMPP: extension of IMP with local variables and mutually
  3421 recursive procedures, by David von Oheimb;
  3422 
  3423 * HOL/Lambda: converted into new-style theory and document;
  3424 
  3425 * HOL/ex/Multiquote: example of multiple nested quotations and
  3426 anti-quotations -- basically a generalized version of de-Bruijn
  3427 representation; very useful in avoiding lifting of operations;
  3428 
  3429 * HOL/record: added general record equality rule to simpset; fixed
  3430 select-update simplification procedure to handle extended records as
  3431 well; admit "r" as field name;
  3432 
  3433 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3434 other numeric types and also as the identity of groups, rings, etc.;
  3435 
  3436 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3437 Types nat and int belong to this axclass;
  3438 
  3439 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3440    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3441    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3442   two terms #m*u and #n*u are replaced by #(m+n)*u
  3443     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3444   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3445     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3446 
  3447 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3448 powerful prover for predicate logic but knows nothing of clasets; see
  3449 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3450 
  3451 * HOL: new version of "case_tac" subsumes both boolean case split and
  3452 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3453 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3454 
  3455 * HOL: simplification no longer dives into case-expressions: only the
  3456 selector expression is simplified, but not the remaining arms; to
  3457 enable full simplification of case-expressions for datatype t, you may
  3458 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3459 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3460 
  3461 * HOL/recdef: the recursion equations generated by 'recdef' for
  3462 function 'f' are now called f.simps instead of f.rules; if all
  3463 termination conditions are proved automatically, these simplification
  3464 rules are added to the simpset, as in primrec; rules may be named
  3465 individually as well, resulting in a separate list of theorems for
  3466 each equation;
  3467 
  3468 * HOL/While is a new theory that provides a while-combinator. It
  3469 permits the definition of tail-recursive functions without the
  3470 provision of a termination measure. The latter is necessary once the
  3471 invariant proof rule for while is applied.
  3472 
  3473 * HOL: new (overloaded) notation for the set of elements below/above
  3474 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3475 
  3476 * HOL: theorems impI, allI, ballI bound as "strip";
  3477 
  3478 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3479 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3480 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3481 
  3482 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3483 
  3484 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3485 main HOL, but was unused);
  3486 
  3487 * HOL: fewer consts declared as global (e.g. have to refer to
  3488 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3489 
  3490 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3491 in case of overlap with user translations (e.g. judgements over
  3492 tuples); (note that the underlying logical represenation is still
  3493 bogus);
  3494 
  3495 
  3496 *** ZF ***
  3497 
  3498 * ZF: simplification automatically cancels common terms in arithmetic
  3499 expressions over nat and int;
  3500 
  3501 * ZF: new treatment of nat to minimize type-checking: all operators
  3502 coerce their operands to a natural number using the function natify,
  3503 making the algebraic laws unconditional;
  3504 
  3505 * ZF: as above, for int: operators coerce their operands to an integer
  3506 using the function intify;
  3507 
  3508 * ZF: the integer library now contains many of the usual laws for the
  3509 orderings, including $<=, and monotonicity laws for $+ and $*;
  3510 
  3511 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3512 simplification;
  3513 
  3514 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3515 to the simplifier and classical reasoner simultaneously;
  3516 
  3517 
  3518 *** General ***
  3519 
  3520 * Provers: blast_tac now handles actual object-logic rules as
  3521 assumptions; note that auto_tac uses blast_tac internally as well;
  3522 
  3523 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3524 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3525 
  3526 * Provers: delrules now handles destruct rules as well (no longer need
  3527 explicit make_elim);
  3528 
  3529 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3530   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3531 use instead the strong form,
  3532   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3533 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3534 from destruct-rules;
  3535 
  3536 * Provers: Simplifier.easy_setup provides a fast path to basic
  3537 Simplifier setup for new object-logics;
  3538 
  3539 * Pure: AST translation rules no longer require constant head on LHS;
  3540 
  3541 * Pure: improved name spaces: ambiguous output is qualified; support
  3542 for hiding of names;
  3543 
  3544 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3545 XSYMBOL_HOME; no longer need to do manual configuration in most
  3546 situations;
  3547 
  3548 * system: compression of ML heaps images may now be controlled via -c
  3549 option of isabelle and isatool usedir (currently only observed by
  3550 Poly/ML);
  3551 
  3552 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3553 useful for remote X11);
  3554 
  3555 * system: provide TAGS file for Isabelle sources;
  3556 
  3557 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3558 order;
  3559 
  3560 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3561 timing flag supersedes proof_timing and Toplevel.trace;
  3562 
  3563 * ML: new combinators |>> and |>>> for incremental transformations
  3564 with secondary results (e.g. certain theory extensions):
  3565 
  3566 * ML: PureThy.add_defs gets additional argument to indicate potential
  3567 overloading (usually false);
  3568 
  3569 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3570 results;
  3571 
  3572 
  3573 
  3574 New in Isabelle99 (October 1999)
  3575 --------------------------------
  3576 
  3577 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3578 
  3579 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3580 are no longer simplified.  (This allows the simplifier to unfold recursive
  3581 functional programs.)  To restore the old behaviour, declare
  3582 
  3583     Delcongs [if_weak_cong];
  3584 
  3585 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3586 complement;
  3587 
  3588 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3589 
  3590 * HOL/datatype: mutual_induct_tac no longer exists --
  3591   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3592 
  3593 * HOL/typedef: fixed type inference for representing set; type
  3594 arguments now have to occur explicitly on the rhs as type constraints;
  3595 
  3596 * ZF: The con_defs part of an inductive definition may no longer refer
  3597 to constants declared in the same theory;
  3598 
  3599 * HOL, ZF: the function mk_cases, generated by the inductive
  3600 definition package, has lost an argument.  To simplify its result, it
  3601 uses the default simpset instead of a supplied list of theorems.
  3602 
  3603 * HOL/List: the constructors of type list are now Nil and Cons;
  3604 
  3605 * Simplifier: the type of the infix ML functions
  3606         setSSolver addSSolver setSolver addSolver
  3607 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3608 for packaging solvers. A solver is created via
  3609         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3610 where the string argument is only a comment.
  3611 
  3612 
  3613 *** Proof tools ***
  3614 
  3615 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3616 decision procedure for linear arithmetic. Currently it is used for
  3617 types `nat', `int', and `real' in HOL (see below); it can, should and
  3618 will be instantiated for other types and logics as well.
  3619 
  3620 * The simplifier now accepts rewrite rules with flexible heads, eg
  3621      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3622   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3623   matching.
  3624 
  3625 
  3626 *** General ***
  3627 
  3628 * New Isabelle/Isar subsystem provides an alternative to traditional
  3629 tactical theorem proving; together with the ProofGeneral/isar user
  3630 interface it offers an interactive environment for developing human
  3631 readable proof documents (Isar == Intelligible semi-automated
  3632 reasoning); for further information see isatool doc isar-ref,
  3633 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3634 
  3635 * improved and simplified presentation of theories: better HTML markup
  3636 (including colors), graph views in several sizes; isatool usedir now
  3637 provides a proper interface for user theories (via -P option); actual
  3638 document preparation based on (PDF)LaTeX is available as well (for
  3639 new-style theories only); see isatool doc system for more information;
  3640 
  3641 * native support for Proof General, both for classic Isabelle and
  3642 Isabelle/Isar;
  3643 
  3644 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3645 using the graph browser tool;
  3646 
  3647 * Isabelle manuals now also available as PDF;
  3648 
  3649 * theory loader rewritten from scratch (may not be fully
  3650 bug-compatible); old loadpath variable has been replaced by show_path,
  3651 add_path, del_path, reset_path functions; new operations such as
  3652 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3653 isatool doc ref);
  3654 
  3655 * improved isatool install: option -k creates KDE application icon,
  3656 option -p DIR installs standalone binaries;
  3657 
  3658 * added ML_PLATFORM setting (useful for cross-platform installations);
  3659 more robust handling of platform specific ML images for SML/NJ;
  3660 
  3661 * the settings environment is now statically scoped, i.e. it is never
  3662 created again in sub-processes invoked from isabelle, isatool, or
  3663 Isabelle;
  3664 
  3665 * path element specification '~~' refers to '$ISABELLE_HOME';
  3666 
  3667 * in locales, the "assumes" and "defines" parts may be omitted if
  3668 empty;
  3669 
  3670 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3671 long arrows);
  3672 
  3673 * new print_mode "HTML";
  3674 
  3675 * new flag show_tags controls display of tags of theorems (which are
  3676 basically just comments that may be attached by some tools);
  3677 
  3678 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3679 mode and goal output format:
  3680 
  3681 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3682 244c244
  3683 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3684 ---
  3685 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3686 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3687 181c181
  3688 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3689 ---
  3690 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3691 
  3692 * function bind_thms stores lists of theorems (cf. bind_thm);
  3693 
  3694 * new shorthand tactics ftac, eatac, datac, fatac;
  3695 
  3696 * qed (and friends) now accept "" as result name; in that case the
  3697 theorem is not stored, but proper checks and presentation of the
  3698 result still apply;
  3699 
  3700 * theorem database now also indexes constants "Trueprop", "all",
  3701 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3702 
  3703 
  3704 *** HOL ***
  3705 
  3706 ** HOL arithmetic **
  3707 
  3708 * There are now decision procedures for linear arithmetic over nat and
  3709 int:
  3710 
  3711 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3712 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3713 are treated as atomic; subformulae not involving type `nat' or `int'
  3714 are ignored; quantified subformulae are ignored unless they are
  3715 positive universal or negative existential. The tactic has to be
  3716 invoked by hand and can be a little bit slow. In particular, the
  3717 running time is exponential in the number of occurrences of `min' and
  3718 `max', and `-' on `nat'.
  3719 
  3720 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3721 (negated) (in)equalities among the premises and the conclusion into
  3722 account (i.e. no compound formulae) and does not know about `min' and
  3723 `max', and `-' on `nat'. It is fast and is used automatically by the
  3724 simplifier.
  3725 
  3726 NB: At the moment, these decision procedures do not cope with mixed
  3727 nat/int formulae where the two parts interact, such as `m < n ==>
  3728 int(m) < int(n)'.
  3729 
  3730 * HOL/Numeral provides a generic theory of numerals (encoded
  3731 efficiently as bit strings); setup for types nat/int/real is in place;
  3732 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3733 int, existing theories and proof scripts may require a few additional
  3734 type constraints;
  3735 
  3736 * integer division and remainder can now be performed on constant
  3737 arguments;
  3738 
  3739 * many properties of integer multiplication, division and remainder
  3740 are now available;
  3741 
  3742 * An interface to the Stanford Validity Checker (SVC) is available through the
  3743 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3744 are proved automatically.  SVC must be installed separately, and its results
  3745 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3746 invocation of the underlying oracle).  For SVC see
  3747   http://verify.stanford.edu/SVC
  3748 
  3749 * IsaMakefile: the HOL-Real target now builds an actual image;
  3750 
  3751 
  3752 ** HOL misc **
  3753 
  3754 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3755 (in Isabelle/Isar) -- by Gertrud Bauer;
  3756 
  3757 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3758 analysis for assembly languages with subtypes;
  3759 
  3760 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3761 -- avoids syntactic ambiguities and treats state, transition, and
  3762 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3763 changed syntax and (many) tactics;
  3764 
  3765 * HOL/inductive: Now also handles more general introduction rules such
  3766   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3767   theorems are now maintained within the theory (maintained via the
  3768   "mono" attribute);
  3769 
  3770 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3771   (using function types) such as
  3772 
  3773   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3774 
  3775 * HOL/record: record_simproc (part of the default simpset) takes care
  3776 of selectors applied to updated records; record_split_tac is no longer
  3777 part of the default claset; update_defs may now be removed from the
  3778 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3779 
  3780   claset_ref () := claset() addSWrapper record_split_wrapper;
  3781   Delsimprocs [record_simproc]
  3782 
  3783 * HOL/typedef: fixed type inference for representing set; type
  3784 arguments now have to occur explicitly on the rhs as type constraints;
  3785 
  3786 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3787 names rather than an ML expression;
  3788 
  3789 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3790 supplied later.  Program schemes can be defined, such as
  3791     "While B C s = (if B s then While B C (C s) else s)"
  3792 where the well-founded relation can be chosen after B and C have been given.
  3793 
  3794 * HOL/List: the constructors of type list are now Nil and Cons;
  3795 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3796 course, ML tools referring to List.list.op # etc. have to be adapted;
  3797 
  3798 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3799 disabled by default; run isabelle with option -m HOL to get back to
  3800 the original Gordon/HOL-style output;
  3801 
  3802 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3803 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3804 
  3805 * HOL basic syntax simplified (more orthogonal): all variants of
  3806 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3807 Eps operator is provided as well: "SOME x. P[x]";
  3808 
  3809 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3810 
  3811 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3812 thus available for user theories;
  3813 
  3814 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3815 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3816 time;
  3817 
  3818 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3819 several times and then mp;
  3820 
  3821 
  3822 *** LK ***
  3823 
  3824 * the notation <<...>> is now available as a notation for sequences of
  3825 formulas;
  3826 
  3827 * the simplifier is now installed
  3828 
  3829 * the axiom system has been generalized (thanks to Soren Heilmann)
  3830 
  3831 * the classical reasoner now has a default rule database
  3832 
  3833 
  3834 *** ZF ***
  3835 
  3836 * new primrec section allows primitive recursive functions to be given
  3837 directly (as in HOL) over datatypes and the natural numbers;
  3838 
  3839 * new tactics induct_tac and exhaust_tac for induction (or case
  3840 analysis) over datatypes and the natural numbers;
  3841 
  3842 * the datatype declaration of type T now defines the recursor T_rec;
  3843 
  3844 * simplification automatically does freeness reasoning for datatype
  3845 constructors;
  3846 
  3847 * automatic type-inference, with AddTCs command to insert new
  3848 type-checking rules;
  3849 
  3850 * datatype introduction rules are now added as Safe Introduction rules
  3851 to the claset;
  3852 
  3853 * the syntax "if P then x else y" is now available in addition to
  3854 if(P,x,y);
  3855 
  3856 
  3857 *** Internal programming interfaces ***
  3858 
  3859 * tuned simplifier trace output; new flag debug_simp;
  3860 
  3861 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3862 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3863 
  3864 * AxClass.axclass_tac lost the theory argument;
  3865 
  3866 * tuned current_goals_markers semantics: begin / end goal avoids
  3867 printing empty lines;
  3868 
  3869 * removed prs and prs_fn hook, which was broken because it did not
  3870 include \n in its semantics, forcing writeln to add one
  3871 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3872 string -> unit if you really want to output text without newline;
  3873 
  3874 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3875 plain output, interface builders may have to enable 'isabelle_font'
  3876 mode to get Isabelle font glyphs as before;
  3877 
  3878 * refined token_translation interface; INCOMPATIBILITY: output length
  3879 now of type real instead of int;
  3880 
  3881 * theory loader actions may be traced via new ThyInfo.add_hook
  3882 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3883 your own database of information attached to *whole* theories -- as
  3884 opposed to intra-theory data slots offered via TheoryDataFun;
  3885 
  3886 * proper handling of dangling sort hypotheses (at last!);
  3887 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3888 extra sort hypotheses that can be witnessed from the type signature;
  3889 the force_strip_shyps flag is gone, any remaining shyps are simply
  3890 left in the theorem (with a warning issued by strip_shyps_warning);
  3891 
  3892 
  3893 
  3894 New in Isabelle98-1 (October 1998)
  3895 ----------------------------------
  3896 
  3897 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3898 
  3899 * several changes of automated proof tools;
  3900 
  3901 * HOL: major changes to the inductive and datatype packages, including
  3902 some minor incompatibilities of theory syntax;
  3903 
  3904 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3905 called `inj_on';
  3906 
  3907 * HOL: removed duplicate thms in Arith:
  3908   less_imp_add_less  should be replaced by  trans_less_add1
  3909   le_imp_add_le      should be replaced by  trans_le_add1
  3910 
  3911 * HOL: unary minus is now overloaded (new type constraints may be
  3912 required);
  3913 
  3914 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3915 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3916 now taken as an integer constant.
  3917 
  3918 * Pure: ML function 'theory_of' renamed to 'theory';
  3919 
  3920 
  3921 *** Proof tools ***
  3922 
  3923 * Simplifier:
  3924   1. Asm_full_simp_tac is now more aggressive.
  3925      1. It will sometimes reorient premises if that increases their power to
  3926         simplify.
  3927      2. It does no longer proceed strictly from left to right but may also
  3928         rotate premises to achieve further simplification.
  3929      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3930      old Asm_full_simp_tac in that it does not rotate premises.
  3931   2. The simplifier now knows a little bit about nat-arithmetic.
  3932 
  3933 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3934 allows for selected deletion of wrappers, by introduction of names for
  3935 wrapper functionals.  This implies that addbefore, addSbefore,
  3936 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3937 and that adding two tactics with the same name overwrites the first
  3938 one (emitting a warning).
  3939   type wrapper = (int -> tactic) -> (int -> tactic)
  3940   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3941   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3942   delWrapper, delSWrapper: claset *  string            -> claset
  3943   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3944 
  3945 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3946 semantics; addbefore now affects only the unsafe part of step_tac
  3947 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3948 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3949 by Force_tac;
  3950 
  3951 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3952 compWrapper; added safe wrapper (and access functions for it);
  3953 
  3954 * HOL/split_all_tac is now much faster and fails if there is nothing
  3955 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3956 and the names of the automatically generated variables have changed.
  3957 split_all_tac has moved within claset() from unsafe wrappers to safe
  3958 wrappers, which means that !!-bound variables are split much more
  3959 aggressively, and safe_tac and clarify_tac now split such variables.
  3960 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3961 Note: the same holds for record_split_tac, which does the job of
  3962 split_all_tac for record fields.
  3963 
  3964 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3965 permanently to the default simpset using Addsplits just like
  3966 Addsimps. They can be removed via Delsplits just like
  3967 Delsimps. Lower-case versions are also available.
  3968 
  3969 * HOL/Simplifier: The rule split_if is now part of the default
  3970 simpset. This means that the simplifier will eliminate all occurrences
  3971 of if-then-else in the conclusion of a goal. To prevent this, you can
  3972 either remove split_if completely from the default simpset by
  3973 `Delsplits [split_if]' or remove it in a specific call of the
  3974 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3975 other case splitting rules to/from the default simpset: every datatype
  3976 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3977 t is the name of the datatype).
  3978 
  3979 * Classical reasoner / Simplifier combination: new force_tac (and
  3980 derivatives Force_tac, force) combines rewriting and classical
  3981 reasoning (and whatever other tools) similarly to auto_tac, but is
  3982 aimed to solve the given subgoal completely.
  3983 
  3984 
  3985 *** General ***
  3986 
  3987 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3988 and `goalw': the theory is no longer needed as an explicit argument -
  3989 the current theory context is used; assumptions are no longer returned
  3990 at the ML-level unless one of them starts with ==> or !!; it is
  3991 recommended to convert to these new commands using isatool fixgoal
  3992 (backup your sources first!);
  3993 
  3994 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3995 the current theory context, and 'theory' to lookup stored theories;
  3996 
  3997 * new theory section 'locale' for declaring constants, assumptions and
  3998 definitions that have local scope;
  3999 
  4000 * new theory section 'nonterminals' for purely syntactic types;
  4001 
  4002 * new theory section 'setup' for generic ML setup functions
  4003 (e.g. package initialization);
  4004 
  4005 * the distribution now includes Isabelle icons: see
  4006 lib/logo/isabelle-{small,tiny}.xpm;
  4007 
  4008 * isatool install - install binaries with absolute references to
  4009 ISABELLE_HOME/bin;
  4010 
  4011 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4012 
  4013 * print mode 'emacs' reserved for Isamode;
  4014 
  4015 * support multiple print (ast) translations per constant name;
  4016 
  4017 * theorems involving oracles are now printed with a suffixed [!];
  4018 
  4019 
  4020 *** HOL ***
  4021 
  4022 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4023 
  4024 * HOL/inductive package reorganized and improved: now supports mutual
  4025 definitions such as
  4026 
  4027   inductive EVEN ODD
  4028     intrs
  4029       null "0 : EVEN"
  4030       oddI "n : EVEN ==> Suc n : ODD"
  4031       evenI "n : ODD ==> Suc n : EVEN"
  4032 
  4033 new theorem list "elims" contains an elimination rule for each of the
  4034 recursive sets; inductive definitions now handle disjunctive premises
  4035 correctly (also ZF);
  4036 
  4037 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4038 "mutual_induct" no longer exists - the induction rule is always
  4039 contained in "induct";
  4040 
  4041 
  4042 * HOL/datatype package re-implemented and greatly improved: now
  4043 supports mutually recursive datatypes such as
  4044 
  4045   datatype
  4046     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4047             | SUM ('a aexp) ('a aexp)
  4048             | DIFF ('a aexp) ('a aexp)
  4049             | NUM 'a
  4050   and
  4051     'a bexp = LESS ('a aexp) ('a aexp)
  4052             | AND ('a bexp) ('a bexp)
  4053             | OR ('a bexp) ('a bexp)
  4054 
  4055 as well as indirectly recursive datatypes such as
  4056 
  4057   datatype
  4058     ('a, 'b) term = Var 'a
  4059                   | App 'b ((('a, 'b) term) list)
  4060 
  4061 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4062 induction on mutually / indirectly recursive datatypes.
  4063 
  4064 Primrec equations are now stored in theory and can be accessed via
  4065 <function_name>.simps.
  4066 
  4067 INCOMPATIBILITIES:
  4068 
  4069   - Theories using datatypes must now have theory Datatype as an
  4070     ancestor.
  4071   - The specific <typename>.induct_tac no longer exists - use the
  4072     generic induct_tac instead.
  4073   - natE has been renamed to nat.exhaust - use exhaust_tac
  4074     instead of res_inst_tac ... natE. Note that the variable
  4075     names in nat.exhaust differ from the names in natE, this
  4076     may cause some "fragile" proofs to fail.
  4077   - The theorems split_<typename>_case and split_<typename>_case_asm
  4078     have been renamed to <typename>.split and <typename>.split_asm.
  4079   - Since default sorts of type variables are now handled correctly,
  4080     some datatype definitions may have to be annotated with explicit
  4081     sort constraints.
  4082   - Primrec definitions no longer require function name and type
  4083     of recursive argument.
  4084 
  4085 Consider using isatool fixdatatype to adapt your theories and proof
  4086 scripts to the new package (backup your sources first!).
  4087 
  4088 
  4089 * HOL/record package: considerably improved implementation; now
  4090 includes concrete syntax for record types, terms, updates; theorems
  4091 for surjective pairing and splitting !!-bound record variables; proof
  4092 support is as follows:
  4093 
  4094   1) standard conversions (selectors or updates applied to record
  4095 constructor terms) are part of the standard simpset;
  4096 
  4097   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4098 made part of standard simpset and claset via addIffs;
  4099 
  4100   3) a tactic for record field splitting (record_split_tac) is part of
  4101 the standard claset (addSWrapper);
  4102 
  4103 To get a better idea about these rules you may retrieve them via
  4104 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4105 the name of your record type.
  4106 
  4107 The split tactic 3) conceptually simplifies by the following rule:
  4108 
  4109   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4110 
  4111 Thus any record variable that is bound by meta-all will automatically
  4112 blow up into some record constructor term, consequently the
  4113 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4114 solve record problems automatically.
  4115 
  4116 
  4117 * reorganized the main HOL image: HOL/Integ and String loaded by
  4118 default; theory Main includes everything;
  4119 
  4120 * automatic simplification of integer sums and comparisons, using cancellation;
  4121 
  4122 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4123 
  4124 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4125 
  4126 * many new identities for unions, intersections, set difference, etc.;
  4127 
  4128 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4129 called split_if, split_split, split_sum_case and split_nat_case (to go
  4130 with add/delsplits);
  4131 
  4132 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4133 (?x::unit) = (); this is made part of the default simpset, which COULD
  4134 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4135 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4136 unit_abs_eta_conv is added in order to counter the effect of
  4137 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4138 %u.f();
  4139 
  4140 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4141 makes more sense);
  4142 
  4143 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4144   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4145   disjointness reasoning but breaking a few old proofs.
  4146 
  4147 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4148 to 'converse' from 'inverse' (for compatibility with ZF and some
  4149 literature);
  4150 
  4151 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4152 the well-founded relation;
  4153 
  4154 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4155     Compl A.  The "Compl" syntax remains available as input syntax for this
  4156     release ONLY.
  4157 
  4158 * HOL/Update: new theory of function updates:
  4159     f(a:=b) == %x. if x=a then b else f x
  4160 may also be iterated as in f(a:=b,c:=d,...);
  4161 
  4162 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4163 
  4164 * HOL/List:
  4165   - new function list_update written xs[i:=v] that updates the i-th
  4166     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4167   - new function `upt' written [i..j(] which generates the list
  4168     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4169     bound write [i..j], which is a shorthand for [i..j+1(].
  4170   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4171 
  4172 * HOL/Arith:
  4173   - removed 'pred' (predecessor) function;
  4174   - generalized some theorems about n-1;
  4175   - many new laws about "div" and "mod";
  4176   - new laws about greatest common divisors (see theory ex/Primes);
  4177 
  4178 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4179 instead of "inverse";
  4180 
  4181 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4182   of the multiset ordering;
  4183 
  4184 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4185   (not included by default);
  4186 
  4187 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4188 
  4189 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4190   programs, i.e. different program variables may have different types.
  4191 
  4192 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4193   [previously, this check worked only if the rewrite rule was unconditional]
  4194   Now rew can involve either definitions or equalities (either == or =).
  4195 
  4196 
  4197 *** ZF ***
  4198 
  4199 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4200   only the theorems proved on ZF.ML;
  4201 
  4202 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4203   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4204   disjointness reasoning but breaking a few old proofs.
  4205 
  4206 * ZF/Update: new theory of function updates
  4207     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4208   may also be iterated as in f(a:=b,c:=d,...);
  4209 
  4210 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4211 
  4212 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4213   [previously, this check worked only if the rewrite rule was unconditional]
  4214   Now rew can involve either definitions or equalities (either == or =).
  4215 
  4216 * case_tac provided for compatibility with HOL
  4217     (like the old excluded_middle_tac, but with subgoals swapped)
  4218 
  4219 
  4220 *** Internal programming interfaces ***
  4221 
  4222 * Pure: several new basic modules made available for general use, see
  4223 also src/Pure/README;
  4224 
  4225 * improved the theory data mechanism to support encapsulation (data
  4226 kind name replaced by private Object.kind, acting as authorization
  4227 key); new type-safe user interface via functor TheoryDataFun; generic
  4228 print_data function becomes basically useless;
  4229 
  4230 * removed global_names compatibility flag -- all theory declarations
  4231 are qualified by default;
  4232 
  4233 * module Pure/Syntax now offers quote / antiquote translation
  4234 functions (useful for Hoare logic etc. with implicit dependencies);
  4235 see HOL/ex/Antiquote for an example use;
  4236 
  4237 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4238 cterm -> thm;
  4239 
  4240 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4241 subgoal;
  4242 
  4243 * Display.print_goals function moved to Locale.print_goals;
  4244 
  4245 * standard print function for goals supports current_goals_markers
  4246 variable for marking begin of proof, end of proof, start of goal; the
  4247 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4248 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4249 for example;
  4250 
  4251 
  4252 
  4253 New in Isabelle98 (January 1998)
  4254 --------------------------------
  4255 
  4256 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4257 
  4258 * changed lexical syntax of terms / types: dots made part of long
  4259 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4260 
  4261 * simpset (and claset) reference variable replaced by functions
  4262 simpset / simpset_ref;
  4263 
  4264 * no longer supports theory aliases (via merge) and non-trivial
  4265 implicit merge of thms' signatures;
  4266 
  4267 * most internal names of constants changed due to qualified names;
  4268 
  4269 * changed Pure/Sequence interface (see Pure/seq.ML);
  4270 
  4271 
  4272 *** General Changes ***
  4273 
  4274 * hierachically structured name spaces (for consts, types, axms, thms
  4275 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4276 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4277 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4278 long_names for fully qualified output names; NOTE: ML programs
  4279 (special tactics, packages etc.) referring to internal names may have
  4280 to be adapted to cope with fully qualified names; in case of severe
  4281 backward campatibility problems try setting 'global_names' at compile
  4282 time to have enrything declared within a flat name space; one may also
  4283 fine tune name declarations in theories via the 'global' and 'local'
  4284 section;
  4285 
  4286 * reimplemented the implicit simpset and claset using the new anytype
  4287 data filed in signatures; references simpset:simpset ref etc. are
  4288 replaced by functions simpset:unit->simpset and
  4289 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4290 to patch your ML files accordingly;
  4291 
  4292 * HTML output now includes theory graph data for display with Java
  4293 applet or isatool browser; data generated automatically via isatool
  4294 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4295 
  4296 * defs may now be conditional; improved rewrite_goals_tac to handle
  4297 conditional equations;
  4298 
  4299 * defs now admits additional type arguments, using TYPE('a) syntax;
  4300 
  4301 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4302 creates a new theory node; implicit merge of thms' signatures is
  4303 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4304 transfer:theory->thm->thm in (rare) cases;
  4305 
  4306 * improved handling of draft signatures / theories; draft thms (and
  4307 ctyps, cterms) are automatically promoted to real ones;
  4308 
  4309 * slightly changed interfaces for oracles: admit many per theory, named
  4310 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4311 
  4312 * print_goals: optional output of const types (set show_consts and
  4313 show_types);
  4314 
  4315 * improved output of warnings (###) and errors (***);
  4316 
  4317 * subgoal_tac displays a warning if the new subgoal has type variables;
  4318 
  4319 * removed old README and Makefiles;
  4320 
  4321 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4322 
  4323 * removed obsolete init_pps and init_database;
  4324 
  4325 * deleted the obsolete tactical STATE, which was declared by
  4326     fun STATE tacfun st = tacfun st st;
  4327 
  4328 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4329 (which abbreviates $HOME);
  4330 
  4331 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4332 use isatool fixseq to adapt your ML programs (this works for fully
  4333 qualified references to the Sequence structure only!);
  4334 
  4335 * use_thy no longer requires writable current directory; it always
  4336 reloads .ML *and* .thy file, if either one is out of date;
  4337 
  4338 
  4339 *** Classical Reasoner ***
  4340 
  4341 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4342 tactics that use classical reasoning to simplify a subgoal without
  4343 splitting it into several subgoals;
  4344 
  4345 * Safe_tac: like safe_tac but uses the default claset;
  4346 
  4347 
  4348 *** Simplifier ***
  4349 
  4350 * added simplification meta rules:
  4351     (asm_)(full_)simplify: simpset -> thm -> thm;
  4352 
  4353 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4354 logics (again);
  4355 
  4356 * added prems argument to simplification procedures;
  4357 
  4358 * HOL, FOL, ZF: added infix function `addsplits':
  4359   instead of `<simpset> setloop (split_tac <thms>)'
  4360   you can simply write `<simpset> addsplits <thms>'
  4361 
  4362 
  4363 *** Syntax ***
  4364 
  4365 * TYPE('a) syntax for type reflection terms;
  4366 
  4367 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4368 
  4369 * pretty printer: changed order of mixfix annotation preference (again!);
  4370 
  4371 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4372 
  4373 
  4374 *** HOL ***
  4375 
  4376 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4377   with `addloop' of the simplifier to faciliate case splitting in premises.
  4378 
  4379 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4380 
  4381 * HOL/Auth: new protocol proofs including some for the Internet
  4382   protocol TLS;
  4383 
  4384 * HOL/Map: new theory of `maps' a la VDM;
  4385 
  4386 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4387 cancelling out common nat summands from =, <, <= (in)equalities, or
  4388 differences; simplification procedures nat_cancel_factor for
  4389 cancelling common factor from =, <, <= (in)equalities over natural
  4390 sums; nat_cancel contains both kinds of procedures, it is installed by
  4391 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4392 
  4393 * HOL/simplifier: terms of the form
  4394   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4395   are rewritten to
  4396   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4397   and those of the form
  4398   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4399   are rewritten to
  4400   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4401 
  4402 * HOL/datatype
  4403   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4404 
  4405   P(t_case f1 ... fn x) =
  4406      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4407         ...
  4408        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4409      )
  4410 
  4411   and a theorem `split_t_case_asm' of the form
  4412 
  4413   P(t_case f1 ... fn x) =
  4414     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4415         ...
  4416        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4417      )
  4418   which can be added to a simpset via `addsplits'. The existing theorems
  4419   expand_list_case and expand_option_case have been renamed to
  4420   split_list_case and split_option_case.
  4421 
  4422 * HOL/Arithmetic:
  4423   - `pred n' is automatically converted to `n-1'.
  4424     Users are strongly encouraged not to use `pred' any longer,
  4425     because it will disappear altogether at some point.
  4426   - Users are strongly encouraged to write "0 < n" rather than
  4427     "n ~= 0". Theorems and proof tools have been modified towards this
  4428     `standard'.
  4429 
  4430 * HOL/Lists:
  4431   the function "set_of_list" has been renamed "set" (and its theorems too);
  4432   the function "nth" now takes its arguments in the reverse order and
  4433   has acquired the infix notation "!" as in "xs!n".
  4434 
  4435 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4436 
  4437 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4438   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4439 
  4440 * HOL/record: extensible records with schematic structural subtyping
  4441 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4442 still lacks various theorems and concrete record syntax;
  4443 
  4444 
  4445 *** HOLCF ***
  4446 
  4447 * removed "axioms" and "generated by" sections;
  4448 
  4449 * replaced "ops" section by extended "consts" section, which is capable of
  4450   handling the continuous function space "->" directly;
  4451 
  4452 * domain package:
  4453   . proves theorems immediately and stores them in the theory,
  4454   . creates hierachical name space,
  4455   . now uses normal mixfix annotations (instead of cinfix...),
  4456   . minor changes to some names and values (for consistency),
  4457   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4458   . separator between mutual domain defs: changed "," to "and",
  4459   . improved handling of sort constraints;  now they have to
  4460     appear on the left-hand side of the equations only;
  4461 
  4462 * fixed LAM <x,y,zs>.b syntax;
  4463 
  4464 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4465 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4466 
  4467 
  4468 *** FOL and ZF ***
  4469 
  4470 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4471   with `addloop' of the simplifier to faciliate case splitting in premises.
  4472 
  4473 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4474 in HOL, they strip ALL and --> from proved theorems;
  4475 
  4476 
  4477 
  4478 New in Isabelle94-8 (May 1997)
  4479 ------------------------------
  4480 
  4481 *** General Changes ***
  4482 
  4483 * new utilities to build / run / maintain Isabelle etc. (in parts
  4484 still somewhat experimental); old Makefiles etc. still functional;
  4485 
  4486 * new 'Isabelle System Manual';
  4487 
  4488 * INSTALL text, together with ./configure and ./build scripts;
  4489 
  4490 * reimplemented type inference for greater efficiency, better error
  4491 messages and clean internal interface;
  4492 
  4493 * prlim command for dealing with lots of subgoals (an easier way of
  4494 setting goals_limit);
  4495 
  4496 
  4497 *** Syntax ***
  4498 
  4499 * supports alternative (named) syntax tables (parser and pretty
  4500 printer); internal interface is provided by add_modesyntax(_i);
  4501 
  4502 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4503 be used in conjunction with the Isabelle symbol font; uses the
  4504 "symbols" syntax table;
  4505 
  4506 * added token_translation interface (may translate name tokens in
  4507 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4508 the current print_mode); IMPORTANT: user print translation functions
  4509 are responsible for marking newly introduced bounds
  4510 (Syntax.mark_boundT);
  4511 
  4512 * token translations for modes "xterm" and "xterm_color" that display
  4513 names in bold, underline etc. or colors (which requires a color
  4514 version of xterm);
  4515 
  4516 * infixes may now be declared with names independent of their syntax;
  4517 
  4518 * added typed_print_translation (like print_translation, but may
  4519 access type of constant);
  4520 
  4521 
  4522 *** Classical Reasoner ***
  4523 
  4524 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4525 some limitations.  Blast_tac...
  4526   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4527   + ignores elimination rules that don't have the correct format
  4528         (the conclusion MUST be a formula variable)
  4529   + ignores types, which can make HOL proofs fail
  4530   + rules must not require higher-order unification, e.g. apply_type in ZF
  4531     [message "Function Var's argument not a bound variable" relates to this]
  4532   + its proof strategy is more general but can actually be slower
  4533 
  4534 * substitution with equality assumptions no longer permutes other
  4535 assumptions;
  4536 
  4537 * minor changes in semantics of addafter (now called addaltern); renamed
  4538 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4539 (and access functions for it);
  4540 
  4541 * improved combination of classical reasoner and simplifier:
  4542   + functions for handling clasimpsets
  4543   + improvement of addss: now the simplifier is called _after_ the
  4544     safe steps.
  4545   + safe variant of addss called addSss: uses safe simplifications
  4546     _during_ the safe steps. It is more complete as it allows multiple
  4547     instantiations of unknowns (e.g. with slow_tac).
  4548 
  4549 *** Simplifier ***
  4550 
  4551 * added interface for simplification procedures (functions that
  4552 produce *proven* rewrite rules on the fly, depending on current
  4553 redex);
  4554 
  4555 * ordering on terms as parameter (used for ordered rewriting);
  4556 
  4557 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4558 
  4559 * the solver is now split into a safe and an unsafe part.
  4560 This should be invisible for the normal user, except that the
  4561 functions setsolver and addsolver have been renamed to setSolver and
  4562 addSolver; added safe_asm_full_simp_tac;
  4563 
  4564 
  4565 *** HOL ***
  4566 
  4567 * a generic induction tactic `induct_tac' which works for all datatypes and
  4568 also for type `nat';
  4569 
  4570 * a generic case distinction tactic `exhaust_tac' which works for all
  4571 datatypes and also for type `nat';
  4572 
  4573 * each datatype comes with a function `size';
  4574 
  4575 * patterns in case expressions allow tuple patterns as arguments to
  4576 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4577 
  4578 * primrec now also works with type nat;
  4579 
  4580 * recdef: a new declaration form, allows general recursive functions to be
  4581 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4582 
  4583 * the constant for negation has been renamed from "not" to "Not" to
  4584 harmonize with FOL, ZF, LK, etc.;
  4585 
  4586 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4587 infinite lists;
  4588 
  4589 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4590 
  4591 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4592 problems in commutative rings, using axiomatic type classes for + and *;
  4593 
  4594 * more examples in HOL/MiniML and HOL/Auth;
  4595 
  4596 * more default rewrite rules for quantifiers, union/intersection;
  4597 
  4598 * a new constant `arbitrary == @x.False';
  4599 
  4600 * HOLCF/IOA replaces old HOL/IOA;
  4601 
  4602 * HOLCF changes: derived all rules and arities
  4603   + axiomatic type classes instead of classes
  4604   + typedef instead of faking type definitions
  4605   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4606   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4607   + eliminated the types void, one, tr
  4608   + use unit lift and bool lift (with translations) instead of one and tr
  4609   + eliminated blift from Lift3.thy (use Def instead of blift)
  4610   all eliminated rules are derived as theorems --> no visible changes ;
  4611 
  4612 
  4613 *** ZF ***
  4614 
  4615 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4616 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4617 as ZF_cs addSIs [equalityI];
  4618 
  4619 
  4620 
  4621 New in Isabelle94-7 (November 96)
  4622 ---------------------------------
  4623 
  4624 * allowing negative levels (as offsets) in prlev and choplev;
  4625 
  4626 * super-linear speedup for large simplifications;
  4627 
  4628 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4629 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4630 FAIL); can suppress it using the command Delsimps (ex_simps @
  4631 all_simps); De Morgan laws are also now included, by default;
  4632 
  4633 * improved printing of ==>  :  ~:
  4634 
  4635 * new object-logic "Sequents" adds linear logic, while replacing LK
  4636 and Modal (thanks to Sara Kalvala);
  4637 
  4638 * HOL/Auth: correctness proofs for authentication protocols;
  4639 
  4640 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4641 examples on HOL/Auth);
  4642 
  4643 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4644 the rewriter and classical reasoner simultaneously;
  4645 
  4646 * function uresult no longer returns theorems in "standard" format;
  4647 regain previous version by: val uresult = standard o uresult;
  4648 
  4649 
  4650 
  4651 New in Isabelle94-6
  4652 -------------------
  4653 
  4654 * oracles -- these establish an interface between Isabelle and trusted
  4655 external reasoners, which may deliver results as theorems;
  4656 
  4657 * proof objects (in particular record all uses of oracles);
  4658 
  4659 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4660 
  4661 * "constdefs" section in theory files;
  4662 
  4663 * "primrec" section (HOL) no longer requires names;
  4664 
  4665 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4666 
  4667 
  4668 
  4669 New in Isabelle94-5
  4670 -------------------
  4671 
  4672 * reduced space requirements;
  4673 
  4674 * automatic HTML generation from theories;
  4675 
  4676 * theory files no longer require "..." (quotes) around most types;
  4677 
  4678 * new examples, including two proofs of the Church-Rosser theorem;
  4679 
  4680 * non-curried (1994) version of HOL is no longer distributed;
  4681 
  4682 
  4683 
  4684 New in Isabelle94-4
  4685 -------------------
  4686 
  4687 * greatly reduced space requirements;
  4688 
  4689 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4690 
  4691 * searchable theorem database (see the section "Retrieving theorems" on
  4692 page 8 of the Reference Manual);
  4693 
  4694 * new examples, including Grabczewski's monumental case study of the
  4695 Axiom of Choice;
  4696 
  4697 * The previous version of HOL renamed to Old_HOL;
  4698 
  4699 * The new version of HOL (previously called CHOL) uses a curried syntax
  4700 for functions.  Application looks like f a b instead of f(a,b);
  4701 
  4702 * Mutually recursive inductive definitions finally work in HOL;
  4703 
  4704 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4705 translates to the operator "split";
  4706 
  4707 
  4708 
  4709 New in Isabelle94-3
  4710 -------------------
  4711 
  4712 * new infix operator, addss, allowing the classical reasoner to
  4713 perform simplification at each step of its search.  Example:
  4714         fast_tac (cs addss ss)
  4715 
  4716 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4717 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4718 look like (a,b) instead of <a,b>;
  4719 
  4720 * PLEASE NOTE: CHOL will eventually replace HOL!
  4721 
  4722 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4723 It translates to the operator "split".  A new theory of integers is available;
  4724 
  4725 * In ZF, integer numerals now denote two's-complement binary integers.
  4726 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4727 
  4728 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4729 of the Axiom of Choice;
  4730 
  4731 
  4732 
  4733 New in Isabelle94-2
  4734 -------------------
  4735 
  4736 * Significantly faster resolution;
  4737 
  4738 * the different sections in a .thy file can now be mixed and repeated
  4739 freely;
  4740 
  4741 * Database of theorems for FOL, HOL and ZF.  New
  4742 commands including qed, qed_goal and bind_thm store theorems in the database.
  4743 
  4744 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4745 a given theory (thms_of), or find out what theory a theorem was proved in
  4746 (theory_of_thm);
  4747 
  4748 * Bugs fixed in the inductive definition and datatype packages;
  4749 
  4750 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4751 and HOL_dup_cs obsolete;
  4752 
  4753 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4754 have been removed;
  4755 
  4756 * Simpler definition of function space in ZF;
  4757 
  4758 * new results about cardinal and ordinal arithmetic in ZF;
  4759 
  4760 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4761 types;
  4762 
  4763 
  4764 $Id$