NEWS
author haftmann
Sat May 19 11:33:57 2007 +0200 (2007-05-19)
changeset 23029 79ee75dc1e59
parent 23013 c38c9039dc13
child 23102 559709b43104
permissions -rw-r--r--
constant op @ now named append
     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/Pretty_Int.thy: maps HOL numerals on target language integer literals
   554     when generating code.
   555 
   556 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   557     when generating code.
   558 
   559 * Library/Commutative_Ring.thy: switched from recdef to function package;
   560     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   561 
   562 * Some steps towards more uniform lattice theory development in HOL.
   563 
   564     constants "meet" and "join" now named "inf" and "sup"
   565     constant "Meet" now named "Inf"
   566 
   567     classes "meet_semilorder" and "join_semilorder" now named
   568       "lower_semilattice" and "upper_semilattice"
   569     class "lorder" now named "lattice"
   570     class "comp_lat" now named "complete_lattice"
   571 
   572     Instantiation of lattice classes allows explicit definitions
   573     for "inf" and "sup" operations.
   574 
   575   INCOMPATIBILITY. Theorem renames:
   576 
   577     meet_left_le            ~> inf_le1
   578     meet_right_le           ~> inf_le2
   579     join_left_le            ~> sup_ge1
   580     join_right_le           ~> sup_ge2
   581     meet_join_le            ~> inf_sup_ord
   582     le_meetI                ~> le_infI
   583     join_leI                ~> le_supI
   584     le_meet                 ~> le_inf_iff
   585     le_join                 ~> ge_sup_conv
   586     meet_idempotent         ~> inf_idem
   587     join_idempotent         ~> sup_idem
   588     meet_comm               ~> inf_commute
   589     join_comm               ~> sup_commute
   590     meet_leI1               ~> le_infI1
   591     meet_leI2               ~> le_infI2
   592     le_joinI1               ~> le_supI1
   593     le_joinI2               ~> le_supI2
   594     meet_assoc              ~> inf_assoc
   595     join_assoc              ~> sup_assoc
   596     meet_left_comm          ~> inf_left_commute
   597     meet_left_idempotent    ~> inf_left_idem
   598     join_left_comm          ~> sup_left_commute
   599     join_left_idempotent    ~> sup_left_idem
   600     meet_aci                ~> inf_aci
   601     join_aci                ~> sup_aci
   602     le_def_meet             ~> le_iff_inf
   603     le_def_join             ~> le_iff_sup
   604     join_absorp2            ~> sup_absorb2
   605     join_absorp1            ~> sup_absorb1
   606     meet_absorp1            ~> inf_absorb1
   607     meet_absorp2            ~> inf_absorb2
   608     meet_join_absorp        ~> inf_sup_absorb
   609     join_meet_absorp        ~> sup_inf_absorb
   610     distrib_join_le         ~> distrib_sup_le
   611     distrib_meet_le         ~> distrib_inf_le
   612 
   613     add_meet_distrib_left   ~> add_inf_distrib_left
   614     add_join_distrib_left   ~> add_sup_distrib_left
   615     is_join_neg_meet        ~> is_join_neg_inf
   616     is_meet_neg_join        ~> is_meet_neg_sup
   617     add_meet_distrib_right  ~> add_inf_distrib_right
   618     add_join_distrib_right  ~> add_sup_distrib_right
   619     add_meet_join_distribs  ~> add_sup_inf_distribs
   620     join_eq_neg_meet        ~> sup_eq_neg_inf
   621     meet_eq_neg_join        ~> inf_eq_neg_sup
   622     add_eq_meet_join        ~> add_eq_inf_sup
   623     meet_0_imp_0            ~> inf_0_imp_0
   624     join_0_imp_0            ~> sup_0_imp_0
   625     meet_0_eq_0             ~> inf_0_eq_0
   626     join_0_eq_0             ~> sup_0_eq_0
   627     neg_meet_eq_join        ~> neg_inf_eq_sup
   628     neg_join_eq_meet        ~> neg_sup_eq_inf
   629     join_eq_if              ~> sup_eq_if
   630 
   631     mono_meet               ~> mono_inf
   632     mono_join               ~> mono_sup
   633     meet_bool_eq            ~> inf_bool_eq
   634     join_bool_eq            ~> sup_bool_eq
   635     meet_fun_eq             ~> inf_fun_eq
   636     join_fun_eq             ~> sup_fun_eq
   637     meet_set_eq             ~> inf_set_eq
   638     join_set_eq             ~> sup_set_eq
   639     meet1_iff               ~> inf1_iff
   640     meet2_iff               ~> inf2_iff
   641     meet1I                  ~> inf1I
   642     meet2I                  ~> inf2I
   643     meet1D1                 ~> inf1D1
   644     meet2D1                 ~> inf2D1
   645     meet1D2                 ~> inf1D2
   646     meet2D2                 ~> inf2D2
   647     meet1E                  ~> inf1E
   648     meet2E                  ~> inf2E
   649     join1_iff               ~> sup1_iff
   650     join2_iff               ~> sup2_iff
   651     join1I1                 ~> sup1I1
   652     join2I1                 ~> sup2I1
   653     join1I1                 ~> sup1I1
   654     join2I2                 ~> sup1I2
   655     join1CI                 ~> sup1CI
   656     join2CI                 ~> sup2CI
   657     join1E                  ~> sup1E
   658     join2E                  ~> sup2E
   659 
   660     is_meet_Meet            ~> is_meet_Inf
   661     Meet_bool_def           ~> Inf_bool_def
   662     Meet_fun_def            ~> Inf_fun_def
   663     Meet_greatest           ~> Inf_greatest
   664     Meet_lower              ~> Inf_lower
   665     Meet_set_def            ~> Inf_set_def
   666 
   667     listsp_meetI            ~> listsp_infI
   668     listsp_meet_eq          ~> listsp_inf_eq
   669 
   670     meet_min                ~> inf_min
   671     join_max                ~> sup_max
   672 
   673 * Classes "order" and "linorder": facts "refl", "trans" and
   674 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   675 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   676 
   677 * Classes "order" and "linorder": 
   678 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   679 proofs changed.
   680 
   681 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   682 INCOMPATIBILITY.
   683 
   684 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   685 INCOMPATIBILITY.
   686 
   687 * Added syntactic class "size"; overloaded constant "size" now has
   688 type "'a::size ==> bool"
   689 
   690 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   691 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   692 
   693 * Added method "lexicographic_order" automatically synthesizes
   694 termination relations as lexicographic combinations of size measures
   695 -- 'function' package.
   696 
   697 * HOL/records: generalised field-update to take a function on the
   698 field rather than the new value: r(|A := x|) is translated to A_update
   699 (K x) r The K-combinator that is internally used is called K_record.
   700 INCOMPATIBILITY: Usage of the plain update functions has to be
   701 adapted.
   702  
   703 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   704 0 * x = 0, which are required for a semiring.  Richer structures do
   705 not inherit from semiring_0 anymore, because this property is a
   706 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   707 semiring_0, there is more to prove, but this is mostly trivial.
   708 
   709 * axclass "recpower" was generalized to arbitrary monoids, not just
   710 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   711 commutativity or a semiring property, add the corresponding classes.
   712 
   713 * Unified locale partial_order with class definition (cf. theory
   714 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   715 
   716 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   717 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   718 Isar level, use abbreviations instead.
   719 
   720 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   721 rarely occuring name references (e.g. ``List.op mem.simps'') require
   722 renaming (e.g. ``List.memberl.simps'').
   723 
   724 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   725 INCOMPATIBILITY.
   726 
   727 * Added theory Code_Generator providing class 'eq', allowing for code
   728 generation with polymorphic equality.
   729 
   730 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   731 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   732 significant changes for setting up numeral syntax for types:
   733 
   734   - new constants Numeral.pred and Numeral.succ instead
   735       of former Numeral.bin_pred and Numeral.bin_succ.
   736   - Use integer operations instead of bin_add, bin_mult and so on.
   737   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   738   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   739 
   740 See HOL/Integ/IntArith.thy for an example setup.
   741 
   742 * New top level command 'normal_form' computes the normal form of a
   743 term that may contain free variables. For example ``normal_form
   744 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   745 suitable for heavy-duty computations because the functions are
   746 compiled to ML first.
   747 
   748 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   749 25 like -->); output depends on the "iff" print_mode, the default is
   750 "A = B" (with priority 50).
   751 
   752 * Renamed constants in HOL.thy and Orderings.thy:
   753     op +   ~> HOL.plus_class.plus
   754     op -   ~> HOL.minus_class.minus
   755     uminus ~> HOL.minus_class.uminus
   756     op *   ~> HOL.times_class.times
   757     op <   ~> Orderings.ord_class.less
   758     op <=  ~> Orderings.ord_class.less_eq
   759 
   760 Adaptions may be required in the following cases:
   761 
   762 a) User-defined constants using any of the names "plus", "minus", "times",
   763 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   764 may go wrong.
   765 INCOMPATIBILITY: use more specific names.
   766 
   767 b) Variables named "plus", "minus", "times", "less", "less_eq"
   768 INCOMPATIBILITY: use more specific names.
   769 
   770 c) Permutative equations (e.g. "a + b = b + a")
   771 Since the change of names also changes the order of terms, permutative
   772 rewrite rules may get applied in a different order. Experience shows that
   773 this is rarely the case (only two adaptions in the whole Isabelle
   774 distribution).
   775 INCOMPATIBILITY: rewrite proofs
   776 
   777 d) ML code directly refering to constant names
   778 This in general only affects hand-written proof tactics, simprocs and so on.
   779 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   780 of const_name ML antiquotations.
   781 
   782 * Relations less (<) and less_eq (<=) are also available on type bool.
   783 Modified syntax to disallow nesting without explicit parentheses,
   784 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   785 
   786 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   787 
   788 * Relation composition operator "op O" now has precedence 75 and binds
   789 stronger than union and intersection. INCOMPATIBILITY.
   790 
   791 * The old set interval syntax "{m..n(}" (and relatives) has been
   792 removed.  Use "{m..<n}" (and relatives) instead.
   793 
   794 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   795 "t = s" to False (by simproc "neq_simproc").  For backward
   796 compatibility this can be disabled by ML "reset use_neq_simproc".
   797 
   798 * "m dvd n" where m and n are numbers is evaluated to True/False by
   799 simp.
   800 
   801 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   802 
   803 * Theorem setsum_mult renamed to setsum_right_distrib.
   804 
   805 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   806 ``rule'' method.
   807 
   808 * Reimplemented methods ``sat'' and ``satx'', with several
   809 improvements: goals no longer need to be stated as "<prems> ==>
   810 False", equivalences (i.e. "=" on type bool) are handled, variable
   811 names of the form "lit_<n>" are no longer reserved, significant
   812 speedup.
   813 
   814 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   815 zChaff is still supported as well.
   816 
   817 * 'inductive' and 'datatype': provide projections of mutual rules,
   818 bundled as foo_bar.inducts;
   819 
   820 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   821 Library.
   822 
   823 * Library: moved theory Accessible_Part to main HOL.
   824 
   825 * Library: added theory Coinductive_List of potentially infinite lists
   826 as greatest fixed-point.
   827 
   828 * Library: added theory AssocList which implements (finite) maps as
   829 association lists.
   830 
   831 * Added proof method ``evaluation'' for efficiently solving a goal
   832 (i.e. a boolean expression) by compiling it to ML. The goal is
   833 "proved" (via an oracle) if it evaluates to True.
   834 
   835 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   836 also when invoked by the simplifier.  This results in the simplifier
   837 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   838 fast_arith_split_limit to 0 to obtain the old behavior.
   839 
   840 * Support for hex (0x20) and binary (0b1001) numerals.
   841 
   842 * New method: reify eqs (t), where eqs are equations for an
   843 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   844 parameter, computes a term s::'b and a list xs::'a list and proves the
   845 theorem I xs s = t. This is also known as reification or quoting. The
   846 resulting theorem is applied to the subgoal to substitute t with I xs
   847 s.  If t is omitted, the subgoal itself is reified.
   848 
   849 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   850 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   851 where f is supposed to be a computable function (in the sense of code
   852 generattion). The method uses reify to compute s and xs as above then
   853 applies corr_thm and uses normalization by evaluation to "prove" f s =
   854 r and finally gets the theorem t = r, which is again applied to the
   855 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   856 
   857 * Reflection: Automatic refification now handels binding, an example
   858 is available in HOL/ex/ReflectionEx.thy
   859 
   860 
   861 *** HOL-Algebra ***
   862 
   863 * Formalisation of ideals and the quotient construction over rings.
   864 
   865 * Order and lattice theory no longer based on records.
   866 INCOMPATIBILITY.
   867 
   868 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   869 greatest_closed.  INCOMPATIBILITY.
   870 
   871 * Method algebra is now set up via an attribute.  For examples see
   872 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   873 of algebraic structures.
   874 
   875 * Renamed theory CRing to Ring.
   876 
   877 
   878 *** HOL-Complex ***
   879 
   880 * Theory Real: new method ferrack implements quantifier elimination
   881 for linear arithmetic over the reals. The quantifier elimination
   882 feature is used only for decision, for compatibility with arith. This
   883 means a goal is either solved or left unchanged, no simplification.
   884 
   885 * Hyperreal: Functions root and sqrt are now defined on negative real
   886 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
   887 Nonnegativity side conditions have been removed from many lemmas, so
   888 that more subgoals may now be solved by simplification; potential
   889 INCOMPATIBILITY.
   890 
   891 * Real: New axiomatic classes formalize real normed vector spaces and
   892 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   893 and norm :: 'a => real.
   894 
   895 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   896 from reals into other types. The overloaded constant Reals :: 'a set
   897 is now defined as range of_real; potential INCOMPATIBILITY.
   898 
   899 * Real: ML code generation is supported now and hence also quickcheck.
   900 Reals are implemented as arbitrary precision rationals.
   901 
   902 * Hyperreal: Several constants that previously worked only for the
   903 reals have been generalized, so they now work over arbitrary vector
   904 spaces. Type annotations may need to be added in some cases; potential
   905 INCOMPATIBILITY.
   906 
   907   Infinitesimal  :: ('a::real_normed_vector) star set
   908   HFinite        :: ('a::real_normed_vector) star set
   909   HInfinite      :: ('a::real_normed_vector) star set
   910   approx         :: ('a::real_normed_vector) star => 'a star => bool
   911   monad          :: ('a::real_normed_vector) star => 'a star set
   912   galaxy         :: ('a::real_normed_vector) star => 'a star set
   913   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
   914   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   915   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   916   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   917   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   918   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   919   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   920   sgn            :: 'a::real_normed_vector => 'a
   921 
   922 * Complex: Some complex-specific constants are now abbreviations for
   923 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   924 hnorm.  Other constants have been entirely removed in favor of the
   925 polymorphic versions (INCOMPATIBILITY):
   926 
   927   approx        <-- capprox
   928   HFinite       <-- CFinite
   929   HInfinite     <-- CInfinite
   930   Infinitesimal <-- CInfinitesimal
   931   monad         <-- cmonad
   932   galaxy        <-- cgalaxy
   933   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   934   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   935   (ns)deriv     <-- (ns)cderiv
   936 
   937 
   938 *** ML ***
   939 
   940 * Context data interfaces (Theory/Proof/GenericDataFun): removed
   941 name/print, uninitialized data defaults to ad-hoc copy of empty value,
   942 init only required for impure data.  INCOMPATIBILITY: empty really
   943 need to be empty (no dependencies on theory content!)
   944 
   945 * ML within Isar: antiquotations allow to embed statically-checked
   946 formal entities in the source, referring to the context available at
   947 compile-time.  For example:
   948 
   949 ML {* @{typ "'a => 'b"} *}
   950 ML {* @{term "%x. x"} *}
   951 ML {* @{prop "x == y"} *}
   952 ML {* @{ctyp "'a => 'b"} *}
   953 ML {* @{cterm "%x. x"} *}
   954 ML {* @{cprop "x == y"} *}
   955 ML {* @{thm asm_rl} *}
   956 ML {* @{thms asm_rl} *}
   957 ML {* @{const_name c} *}
   958 ML {* @{const_syntax c} *}
   959 ML {* @{context} *}
   960 ML {* @{theory} *}
   961 ML {* @{theory Pure} *}
   962 ML {* @{simpset} *}
   963 ML {* @{claset} *}
   964 ML {* @{clasimpset} *}
   965 
   966 The same works for sources being ``used'' within an Isar context.
   967 
   968 * ML in Isar: improved error reporting; extra verbosity with
   969 Toplevel.debug enabled.
   970 
   971 * Pure/library:
   972 
   973   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   974   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   975 
   976 The semantics of "burrow" is: "take a function with *simulatanously*
   977 transforms a list of value, and apply it *simulatanously* to a list of
   978 list of values of the appropriate type". Compare this with "map" which
   979 would *not* apply its argument function simulatanously but in
   980 sequence; "fold_burrow" has an additional context.
   981 
   982 * Pure/library: functions map2 and fold2 with curried syntax for
   983 simultanous mapping and folding:
   984 
   985     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   986     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   987 
   988 * Pure/library: indexed lists - some functions in the Isabelle library
   989 treating lists over 'a as finite mappings from [0...n] to 'a have been
   990 given more convenient names and signatures reminiscent of similar
   991 functions for alists, tables, etc:
   992 
   993   val nth: 'a list -> int -> 'a 
   994   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   995   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   996 
   997 Note that fold_index starts counting at index 0, not 1 like foldln
   998 used to.
   999 
  1000 * Pure/library: added general ``divide_and_conquer'' combinator on
  1001 lists.
  1002 
  1003 * Pure/General/table.ML: the join operations now works via exceptions
  1004 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1005 admits slightly more efficient complex applications.
  1006 
  1007 * Pure: datatype Context.generic joins theory/Proof.context and
  1008 provides some facilities for code that works in either kind of
  1009 context, notably GenericDataFun for uniform theory and proof data.
  1010 
  1011 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1012 use Context.generic instead of just theory.
  1013 
  1014 * Pure: simplified internal attribute type, which is now always
  1015 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1016 vs. local (Proof.context) attributes have been discontinued, while
  1017 minimizing code duplication.  Thm.rule_attribute and
  1018 Thm.declaration_attribute build canonical attributes; see also
  1019 structure Context for further operations on Context.generic, notably
  1020 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1021 declarations and definitions.
  1022 
  1023 * Pure/kernel: consts certification ignores sort constraints given in
  1024 signature declarations.  (This information is not relevant to the
  1025 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1026 potential INCOMPATIBILITY.
  1027 
  1028 * Pure: axiomatic type classes are now purely definitional, with
  1029 explicit proofs of class axioms and super class relations performed
  1030 internally.  See Pure/axclass.ML for the main internal interfaces --
  1031 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1032 AxClass.axiomatize_class/classrel/arity supercede
  1033 Sign.add_classes/classrel/arities.
  1034 
  1035 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1036 global/local versions on theory vs. Proof.context have been
  1037 discontinued; Attrib.syntax and Method.syntax have been adapted
  1038 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1039 attributes, methods, etc.
  1040 
  1041 * Pure: several functions of signature "... -> theory -> theory * ..."
  1042 have been reoriented to "... -> theory -> ... * theory" in order to
  1043 allow natural usage in combination with the ||>, ||>>, |-> and
  1044 fold_map combinators.
  1045 
  1046 * Pure: official theorem names (closed derivations) and additional
  1047 comments (tags) are now strictly separate.  Name hints -- which are
  1048 maintained as tags -- may be attached any time without affecting the
  1049 derivation.
  1050 
  1051 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1052 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1053 achieve the old behaviour.
  1054 
  1055 * Pure: the "Goal" constant is now called "prop", supporting a
  1056 slightly more general idea of ``protecting'' meta-level rule
  1057 statements.
  1058 
  1059 * Pure: Logic.(un)varify only works in a global context, which is now
  1060 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1061 Logic.legacy_(un)varify as temporary workaround.
  1062 
  1063 * Pure: structure Name provides scalable operations for generating
  1064 internal variable names, notably Name.variants etc.  This replaces
  1065 some popular functions from term.ML:
  1066 
  1067   Term.variant		->  Name.variant
  1068   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1069   Term.invent_names	->  Name.invent_list
  1070 
  1071 Note that low-level renaming rarely occurs in new code -- operations
  1072 from structure Variable are used instead (see below).
  1073 
  1074 * Pure: structure Variable provides fundamental operations for proper
  1075 treatment of fixed/schematic variables in a context.  For example,
  1076 Variable.import introduces fixes for schematics of given facts and
  1077 Variable.export reverses the effect (up to renaming) -- this replaces
  1078 various freeze_thaw operations.
  1079 
  1080 * Pure: structure Goal provides simple interfaces for
  1081 init/conclude/finish and tactical prove operations (replacing former
  1082 Tactic.prove).  Goal.prove is the canonical way to prove results
  1083 within a given context; Goal.prove_global is a degraded version for
  1084 theory level goals, including a global Drule.standard.  Note that
  1085 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1086 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1087 in a locale context).
  1088 
  1089 * Isar: simplified treatment of user-level errors, using exception
  1090 ERROR of string uniformly.  Function error now merely raises ERROR,
  1091 without any side effect on output channels.  The Isar toplevel takes
  1092 care of proper display of ERROR exceptions.  ML code may use plain
  1093 handle/can/try; cat_error may be used to concatenate errors like this:
  1094 
  1095   ... handle ERROR msg => cat_error msg "..."
  1096 
  1097 Toplevel ML code (run directly or through the Isar toplevel) may be
  1098 embedded into the Isar toplevel with exception display/debug like
  1099 this:
  1100 
  1101   Isar.toplevel (fn () => ...)
  1102 
  1103 INCOMPATIBILITY, removed special transform_error facilities, removed
  1104 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1105 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1106 -- use plain ERROR instead.
  1107 
  1108 * Isar: theory setup now has type (theory -> theory), instead of a
  1109 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1110 
  1111 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1112 subject to ProofContext.debug/verbose flags.
  1113 
  1114 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1115 theory before entering a proof state.  Transactions now always see a
  1116 quasi-functional intermediate checkpoint, both in interactive and
  1117 batch mode.
  1118 
  1119 * Simplifier: the simpset of a running simplification process now
  1120 contains a proof context (cf. Simplifier.the_context), which is the
  1121 very context that the initial simpset has been retrieved from (by
  1122 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1123 (solver, looper etc.) may depend on arbitrary proof data.
  1124 
  1125 * Simplifier.inherit_context inherits the proof context (plus the
  1126 local bounds) of the current simplification process; any simproc
  1127 etc. that calls the Simplifier recursively should do this!  Removed
  1128 former Simplifier.inherit_bounds, which is already included here --
  1129 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1130 specify an explicit context using Simplifier.context/theory_context.
  1131 
  1132 * Simplifier/Classical Reasoner: more abstract interfaces
  1133 change_simpset/claset for modifying the simpset/claset reference of a
  1134 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1135 INCOMPATIBILITY.
  1136 
  1137 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1138 "Trueprop" etc.
  1139 
  1140 
  1141 *** System ***
  1142 
  1143 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1144 locations -- now includes the Isabelle version identifier as well.
  1145 This simplifies use of multiple Isabelle installations.
  1146 
  1147 * isabelle-process: option -S (secure mode) disables some critical
  1148 operations, notably runtime compilation and evaluation of ML source
  1149 code.
  1150 
  1151 
  1152 New in Isabelle2005 (October 2005)
  1153 ----------------------------------
  1154 
  1155 *** General ***
  1156 
  1157 * Theory headers: the new header syntax for Isar theories is
  1158 
  1159   theory <name>
  1160   imports <theory1> ... <theoryN>
  1161   uses <file1> ... <fileM>
  1162   begin
  1163 
  1164 where the 'uses' part is optional.  The previous syntax
  1165 
  1166   theory <name> = <theory1> + ... + <theoryN>:
  1167 
  1168 will disappear in the next release.  Use isatool fixheaders to convert
  1169 existing theory files.  Note that there is no change in ancient
  1170 non-Isar theories now, but these will disappear soon.
  1171 
  1172 * Theory loader: parent theories can now also be referred to via
  1173 relative and absolute paths.
  1174 
  1175 * Command 'find_theorems' searches for a list of criteria instead of a
  1176 list of constants. Known criteria are: intro, elim, dest, name:string,
  1177 simp:term, and any term. Criteria can be preceded by '-' to select
  1178 theorems that do not match. Intro, elim, dest select theorems that
  1179 match the current goal, name:s selects theorems whose fully qualified
  1180 name contain s, and simp:term selects all simplification rules whose
  1181 lhs match term.  Any other term is interpreted as pattern and selects
  1182 all theorems matching the pattern. Available in ProofGeneral under
  1183 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1184 
  1185   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1186 
  1187 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1188 matching the current goal as introduction rule and not having "HOL."
  1189 in their name (i.e. not being defined in theory HOL).
  1190 
  1191 * Command 'thms_containing' has been discontinued in favour of
  1192 'find_theorems'; INCOMPATIBILITY.
  1193 
  1194 * Communication with Proof General is now 8bit clean, which means that
  1195 Unicode text in UTF-8 encoding may be used within theory texts (both
  1196 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1197 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1198 
  1199   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1200   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1201 
  1202 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1203 Classical Reasoner.  Typical big applications run around 2 times
  1204 faster.
  1205 
  1206 
  1207 *** Document preparation ***
  1208 
  1209 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1210 of raw sources.  Only those symbols that do not require additional
  1211 LaTeX packages (depending on comments in isabellesym.sty) are
  1212 displayed properly, everything else is left verbatim.  isatool display
  1213 and isatool print are used as front ends (these are subject to the
  1214 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1215 
  1216 * Command tags control specific markup of certain regions of text,
  1217 notably folding and hiding.  Predefined tags include "theory" (for
  1218 theory begin and end), "proof" for proof commands, and "ML" for
  1219 commands involving ML code; the additional tags "visible" and
  1220 "invisible" are unused by default.  Users may give explicit tag
  1221 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1222 interpretation of tags is determined by the LaTeX job during document
  1223 preparation: see option -V of isatool usedir, or options -n and -t of
  1224 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1225 \isadroptag.
  1226 
  1227 Several document versions may be produced at the same time via isatool
  1228 usedir (the generated index.html will link all of them).  Typical
  1229 specifications include ''-V document=theory,proof,ML'' to present
  1230 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1231 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1232 these parts without any formal replacement text.  The Isabelle site
  1233 default settings produce ''document'' and ''outline'' versions as
  1234 specified above.
  1235 
  1236 * Several new antiquotations:
  1237 
  1238   @{term_type term} prints a term with its type annotated;
  1239 
  1240   @{typeof term} prints the type of a term;
  1241 
  1242   @{const const} is the same as @{term const}, but checks that the
  1243   argument is a known logical constant;
  1244 
  1245   @{term_style style term} and @{thm_style style thm} print a term or
  1246   theorem applying a "style" to it
  1247 
  1248   @{ML text}
  1249 
  1250 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1251 definitions, equations, inequations etc., 'concl' printing only the
  1252 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1253 to print the specified premise.  TermStyle.add_style provides an ML
  1254 interface for introducing further styles.  See also the "LaTeX Sugar"
  1255 document practical applications.  The ML antiquotation prints
  1256 type-checked ML expressions verbatim.
  1257 
  1258 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1259 and 'text' support optional locale specification '(in loc)', which
  1260 specifies the default context for interpreting antiquotations.  For
  1261 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1262 
  1263 * Option 'locale=NAME' of antiquotations specifies an alternative
  1264 context interpreting the subsequent argument.  For example: @{thm
  1265 [locale=lattice] inf_assoc}.
  1266 
  1267 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1268 a proof context.
  1269 
  1270 * Proper output of antiquotations for theory commands involving a
  1271 proof context (such as 'locale' or 'theorem (in loc) ...').
  1272 
  1273 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1274 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1275 
  1276 * isatool usedir: new option -C (default true) controls whether option
  1277 -D should include a copy of the original document directory; -C false
  1278 prevents unwanted effects such as copying of administrative CVS data.
  1279 
  1280 
  1281 *** Pure ***
  1282 
  1283 * Considerably improved version of 'constdefs' command.  Now performs
  1284 automatic type-inference of declared constants; additional support for
  1285 local structure declarations (cf. locales and HOL records), see also
  1286 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1287 sequential dependencies of definitions within a single 'constdefs'
  1288 section; moreover, the declared name needs to be an identifier.  If
  1289 all fails, consider to fall back on 'consts' and 'defs' separately.
  1290 
  1291 * Improved indexed syntax and implicit structures.  First of all,
  1292 indexed syntax provides a notational device for subscripted
  1293 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1294 expressions.  Secondly, in a local context with structure
  1295 declarations, number indexes \<^sub>n or the empty index (default
  1296 number 1) refer to a certain fixed variable implicitly; option
  1297 show_structs controls printing of implicit structures.  Typical
  1298 applications of these concepts involve record types and locales.
  1299 
  1300 * New command 'no_syntax' removes grammar declarations (and
  1301 translations) resulting from the given syntax specification, which is
  1302 interpreted in the same manner as for the 'syntax' command.
  1303 
  1304 * 'Advanced' translation functions (parse_translation etc.) may depend
  1305 on the signature of the theory context being presently used for
  1306 parsing/printing, see also isar-ref manual.
  1307 
  1308 * Improved 'oracle' command provides a type-safe interface to turn an
  1309 ML expression of type theory -> T -> term into a primitive rule of
  1310 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1311 is already included here); see also FOL/ex/IffExample.thy;
  1312 INCOMPATIBILITY.
  1313 
  1314 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1315 before); "cI" is no longer bound, use "c.intro" instead.
  1316 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1317 axclasses vs. locales.
  1318 
  1319 * Improved internal renaming of symbolic identifiers -- attach primes
  1320 instead of base 26 numbers.
  1321 
  1322 * New flag show_question_marks controls printing of leading question
  1323 marks in schematic variable names.
  1324 
  1325 * In schematic variable names, *any* symbol following \<^isub> or
  1326 \<^isup> is now treated as part of the base name.  For example, the
  1327 following works without printing of awkward ".0" indexes:
  1328 
  1329   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1330     by simp
  1331 
  1332 * Inner syntax includes (*(*nested*) comments*).
  1333 
  1334 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1335 annotations as "(00...)".
  1336 
  1337 * Clear separation of logical types and nonterminals, where the latter
  1338 may only occur in 'syntax' specifications or type abbreviations.
  1339 Before that distinction was only partially implemented via type class
  1340 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1341 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1342 exotic syntax specifications may require further adaption
  1343 (e.g. Cube/Cube.thy).
  1344 
  1345 * Removed obsolete type class "logic", use the top sort {} instead.
  1346 Note that non-logical types should be declared as 'nonterminals'
  1347 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1348 specifications.
  1349 
  1350 * Attributes 'induct' and 'cases': type or set names may now be
  1351 locally fixed variables as well.
  1352 
  1353 * Simplifier: can now control the depth to which conditional rewriting
  1354 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1355 Limit.
  1356 
  1357 * Simplifier: simplification procedures may now take the current
  1358 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1359 interface), which is very useful for calling the Simplifier
  1360 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1361 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1362 low-level mk_simproc no longer applies Logic.varify internally, to
  1363 allow for use in a context of fixed variables.
  1364 
  1365 * thin_tac now works even if the assumption being deleted contains !!
  1366 or ==>.  More generally, erule now works even if the major premise of
  1367 the elimination rule contains !! or ==>.
  1368 
  1369 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1370 
  1371 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1372 from Pure, which contains all common declarations already.  Both
  1373 theories are defined via plain Isabelle/Isar .thy files.
  1374 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1375 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1376 use isatool fixcpure to adapt your theory and ML sources.
  1377 
  1378 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1379 selections of theorems in named facts via index ranges.
  1380 
  1381 * 'print_theorems': in theory mode, really print the difference
  1382 wrt. the last state (works for interactive theory development only),
  1383 in proof mode print all local facts (cf. 'print_facts');
  1384 
  1385 * 'hide': option '(open)' hides only base names.
  1386 
  1387 * More efficient treatment of intermediate checkpoints in interactive
  1388 theory development.
  1389 
  1390 * Code generator is now invoked via code_module (incremental code
  1391 generation) and code_library (modular code generation, ML structures
  1392 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1393 must be quoted when used as identifiers.
  1394 
  1395 * New 'value' command for reading, evaluating and printing terms using
  1396 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1397 quoted when used as identifier.
  1398 
  1399 
  1400 *** Locales ***
  1401 
  1402 * New commands for the interpretation of locale expressions in
  1403 theories (1), locales (2) and proof contexts (3).  These generate
  1404 proof obligations from the expression specification.  After the
  1405 obligations have been discharged, theorems of the expression are added
  1406 to the theory, target locale or proof context.  The synopsis of the
  1407 commands is a follows:
  1408 
  1409   (1) interpretation expr inst
  1410   (2) interpretation target < expr
  1411   (3) interpret expr inst
  1412 
  1413 Interpretation in theories and proof contexts require a parameter
  1414 instantiation of terms from the current context.  This is applied to
  1415 specifications and theorems of the interpreted expression.
  1416 Interpretation in locales only permits parameter renaming through the
  1417 locale expression.  Interpretation is smart in that interpretations
  1418 that are active already do not occur in proof obligations, neither are
  1419 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1420 inspect active interpretations of a particular locale.  For details,
  1421 see the Isar Reference manual.  Examples can be found in
  1422 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1423 
  1424 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1425 'interpret' instead.
  1426 
  1427 * New context element 'constrains' for adding type constraints to
  1428 parameters.
  1429 
  1430 * Context expressions: renaming of parameters with syntax
  1431 redeclaration.
  1432 
  1433 * Locale declaration: 'includes' disallowed.
  1434 
  1435 * Proper static binding of attribute syntax -- i.e. types / terms /
  1436 facts mentioned as arguments are always those of the locale definition
  1437 context, independently of the context of later invocations.  Moreover,
  1438 locale operations (renaming and type / term instantiation) are applied
  1439 to attribute arguments as expected.
  1440 
  1441 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1442 actual attributes; rare situations may require Attrib.attribute to
  1443 embed those attributes into Attrib.src that lack concrete syntax.
  1444 Attribute implementations need to cooperate properly with the static
  1445 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1446 Attrib.XXX_thm etc. already do the right thing without further
  1447 intervention.  Only unusual applications -- such as "where" or "of"
  1448 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1449 on the context and the facts involved -- may have to assign parsed
  1450 values to argument tokens explicitly.
  1451 
  1452 * Changed parameter management in theorem generation for long goal
  1453 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1454 theorem statement in rare situations.
  1455 
  1456 * Locale inspection command 'print_locale' omits notes elements.  Use
  1457 'print_locale!' to have them included in the output.
  1458 
  1459 
  1460 *** Provers ***
  1461 
  1462 * Provers/hypsubst.ML: improved version of the subst method, for
  1463 single-step rewriting: it now works in bound variable contexts. New is
  1464 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1465 rewrite a different subterm than the original subst method, which is
  1466 still available as 'simplesubst'.
  1467 
  1468 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1469 and quasi orders.
  1470 
  1471 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1472 reflexive-transitive closure of relations.
  1473 
  1474 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1475 limit (previously hard-coded with a value of 20) user-definable.
  1476 
  1477 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1478 is peformed already.  Object-logics merely need to finish their
  1479 initial simpset configuration as before.  INCOMPATIBILITY.
  1480 
  1481 
  1482 *** HOL ***
  1483 
  1484 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1485 
  1486   syntax (epsilon)
  1487     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1488 
  1489 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1490 and x-symbol; use option '-m epsilon' to get it actually printed.
  1491 Moreover, the mathematically important symbolic identifier \<epsilon>
  1492 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1493 
  1494 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1495 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1496 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1497 support corresponding Isar calculations.
  1498 
  1499 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1500 instead of ":".
  1501 
  1502 * theory SetInterval: changed the syntax for open intervals:
  1503 
  1504   Old       New
  1505   {..n(}    {..<n}
  1506   {)n..}    {n<..}
  1507   {m..n(}   {m..<n}
  1508   {)m..n}   {m<..n}
  1509   {)m..n(}  {m<..<n}
  1510 
  1511 The old syntax is still supported but will disappear in the next
  1512 release.  For conversion use the following Emacs search and replace
  1513 patterns (these are not perfect but work quite well):
  1514 
  1515   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1516   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1517 
  1518 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1519 equalities in commutative rings; method 'algebra' provides a generic
  1520 interface.
  1521 
  1522 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1523 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1524 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1525 be a tuple pattern.
  1526 
  1527 Some new syntax forms are available:
  1528 
  1529   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1530   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1531   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1532   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1533 
  1534 The latter form "\<Sum>x < k. e" used to be based on a separate
  1535 function "Summation", which has been discontinued.
  1536 
  1537 * theory Finite_Set: in structured induction proofs, the insert case
  1538 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1539 (insert F x)'.
  1540 
  1541 * The 'refute' command has been extended to support a much larger
  1542 fragment of HOL, including axiomatic type classes, constdefs and
  1543 typedefs, inductive datatypes and recursion.
  1544 
  1545 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1546 Requires zChaff with proof generation to be installed.  See
  1547 HOL/ex/SAT_Examples.thy for examples.
  1548 
  1549 * Datatype induction via method 'induct' now preserves the name of the
  1550 induction variable. For example, when proving P(xs::'a list) by
  1551 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1552 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1553 in unstructured proof scripts.
  1554 
  1555 * Reworked implementation of records.  Improved scalability for
  1556 records with many fields, avoiding performance problems for type
  1557 inference. Records are no longer composed of nested field types, but
  1558 of nested extension types. Therefore the record type only grows linear
  1559 in the number of extensions and not in the number of fields.  The
  1560 top-level (users) view on records is preserved.  Potential
  1561 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1562 old record representation. The type generated for a record is called
  1563 <record_name>_ext_type.
  1564 
  1565 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1566 proofs triggered by a record definition or a simproc (if
  1567 quick_and_dirty is enabled).  Definitions of large records can take
  1568 quite long.
  1569 
  1570 New simproc record_upd_simproc for simplification of multiple record
  1571 updates enabled by default.  Moreover, trivial updates are also
  1572 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1573 occasionally, since simplification is more powerful by default.
  1574 
  1575 * typedef: proper support for polymorphic sets, which contain extra
  1576 type-variables in the term.
  1577 
  1578 * Simplifier: automatically reasons about transitivity chains
  1579 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1580 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1581 old proofs break occasionally as simplification may now solve more
  1582 goals than previously.
  1583 
  1584 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1585 present.  Works for all partial orders (class "order"), in particular
  1586 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1587 just like y <= x.
  1588 
  1589 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1590 bound variable or a constant then the let is unfolded.  Otherwise
  1591 first a is simplified to b, and then f b is simplified to g. If
  1592 possible we abstract b from g arriving at "let x = b in h x",
  1593 otherwise we unfold the let and arrive at g.  The simproc can be
  1594 enabled/disabled by the reference use_let_simproc.  Potential
  1595 INCOMPATIBILITY since simplification is more powerful by default.
  1596 
  1597 * Classical reasoning: the meson method now accepts theorems as arguments.
  1598 
  1599 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1600 jobs to provide advice on the provability of subgoals.
  1601 
  1602 * Theory OrderedGroup and Ring_and_Field: various additions and
  1603 improvements to faciliate calculations involving equalities and
  1604 inequalities.
  1605 
  1606 The following theorems have been eliminated or modified
  1607 (INCOMPATIBILITY):
  1608 
  1609   abs_eq             now named abs_of_nonneg
  1610   abs_of_ge_0        now named abs_of_nonneg
  1611   abs_minus_eq       now named abs_of_nonpos
  1612   imp_abs_id         now named abs_of_nonneg
  1613   imp_abs_neg_id     now named abs_of_nonpos
  1614   mult_pos           now named mult_pos_pos
  1615   mult_pos_le        now named mult_nonneg_nonneg
  1616   mult_pos_neg_le    now named mult_nonneg_nonpos
  1617   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1618   mult_neg           now named mult_neg_neg
  1619   mult_neg_le        now named mult_nonpos_nonpos
  1620 
  1621 * Theory Parity: added rules for simplifying exponents.
  1622 
  1623 * Theory List:
  1624 
  1625 The following theorems have been eliminated or modified
  1626 (INCOMPATIBILITY):
  1627 
  1628   list_all_Nil       now named list_all.simps(1)
  1629   list_all_Cons      now named list_all.simps(2)
  1630   list_all_conv      now named list_all_iff
  1631   set_mem_eq         now named mem_iff
  1632 
  1633 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1634 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1635 
  1636 
  1637 *** HOL-Complex ***
  1638 
  1639 * Theory RealDef: better support for embedding natural numbers and
  1640 integers in the reals.
  1641 
  1642 The following theorems have been eliminated or modified
  1643 (INCOMPATIBILITY):
  1644 
  1645   exp_ge_add_one_self  now requires no hypotheses
  1646   real_of_int_add      reversed direction of equality (use [symmetric])
  1647   real_of_int_minus    reversed direction of equality (use [symmetric])
  1648   real_of_int_diff     reversed direction of equality (use [symmetric])
  1649   real_of_int_mult     reversed direction of equality (use [symmetric])
  1650 
  1651 * Theory RComplete: expanded support for floor and ceiling functions.
  1652 
  1653 * Theory Ln is new, with properties of the natural logarithm
  1654 
  1655 * Hyperreal: There is a new type constructor "star" for making
  1656 nonstandard types.  The old type names are now type synonyms:
  1657 
  1658   hypreal = real star
  1659   hypnat = nat star
  1660   hcomplex = complex star
  1661 
  1662 * Hyperreal: Many groups of similarly-defined constants have been
  1663 replaced by polymorphic versions (INCOMPATIBILITY):
  1664 
  1665   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1666 
  1667   starset      <-- starsetNat, starsetC
  1668   *s*          <-- *sNat*, *sc*
  1669   starset_n    <-- starsetNat_n, starsetC_n
  1670   *sn*         <-- *sNatn*, *scn*
  1671   InternalSets <-- InternalNatSets, InternalCSets
  1672 
  1673   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1674   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1675   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1676   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1677   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1678 
  1679 * Hyperreal: Many type-specific theorems have been removed in favor of
  1680 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1681 
  1682   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1683   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1684   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1685   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1686   right_minus <-- hypreal_add_minus
  1687   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1688   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1689   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1690   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1691   mult_1_right <-- hcomplex_mult_one_right
  1692   mult_zero_left <-- hcomplex_mult_zero_left
  1693   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1694   right_distrib <-- hypnat_add_mult_distrib2
  1695   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1696   right_inverse <-- hypreal_mult_inverse
  1697   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1698   order_refl <-- {hypreal,hypnat}_le_refl
  1699   order_trans <-- {hypreal,hypnat}_le_trans
  1700   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1701   order_less_le <-- {hypreal,hypnat}_less_le
  1702   linorder_linear <-- {hypreal,hypnat}_le_linear
  1703   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1704   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1705   add_nonneg_nonneg <-- hypreal_le_add_order
  1706 
  1707 * Hyperreal: Separate theorems having to do with type-specific
  1708 versions of constants have been merged into theorems that apply to the
  1709 new polymorphic constants (INCOMPATIBILITY):
  1710 
  1711   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1712   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1713   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1714   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1715   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1716   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1717   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1718   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1719   STAR_diff <-- {STAR,STARC}_diff
  1720   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1721     STARC_hcomplex_of_complex}_image_subset
  1722   starset_n_Un <-- starset{Nat,C}_n_Un
  1723   starset_n_Int <-- starset{Nat,C}_n_Int
  1724   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1725   starset_n_diff <-- starset{Nat,C}_n_diff
  1726   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1727   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1728   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1729   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1730   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1731   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1732   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1733   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1734   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1735   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1736   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1737   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1738   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1739   starfun_diff <-- starfun{C,RC,CR}_diff
  1740   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1741   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1742   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1743   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1744   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1745   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1746   starfun_Id <-- starfunC_Id
  1747   starfun_approx <-- starfun{Nat,CR}_approx
  1748   starfun_capprox <-- starfun{C,RC}_capprox
  1749   starfun_abs <-- starfunNat_rabs
  1750   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1751   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1752   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1753   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1754   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1755   starfun_add_approx <-- starfunCR_add_approx
  1756   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1757   starfun_divide <-- starfun{C,CR,RC}_divide
  1758   starfun_n <-- starfun{Nat,C}_n
  1759   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1760   starfun_n_add <-- starfun{Nat,C}_n_add
  1761   starfun_n_add_minus <-- starfunNat_n_add_minus
  1762   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1763   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1764   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1765 
  1766   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1767   star_n_minus <-- {hypreal,hcomplex}_minus
  1768   star_n_diff <-- {hypreal,hcomplex}_diff
  1769   star_n_mult <-- {hypreal,hcomplex}_mult
  1770   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1771   star_n_le <-- {hypreal,hypnat}_le
  1772   star_n_less <-- {hypreal,hypnat}_less
  1773   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1774   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1775   star_n_abs <-- hypreal_hrabs
  1776   star_n_divide <-- hcomplex_divide
  1777 
  1778   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1779   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1780   star_of_diff <-- hypreal_of_real_diff
  1781   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1782   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1783   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1784   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1785   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1786   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1787   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1788   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1789   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1790   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1791   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1792   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1793   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1794   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1795   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1796   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1797   star_of_power <-- hypreal_of_real_power
  1798   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1799 
  1800 * Hyperreal: new method "transfer" that implements the transfer
  1801 principle of nonstandard analysis. With a subgoal that mentions
  1802 nonstandard types like "'a star", the command "apply transfer"
  1803 replaces it with an equivalent one that mentions only standard types.
  1804 To be successful, all free variables must have standard types; non-
  1805 standard variables must have explicit universal quantifiers.
  1806 
  1807 * Hyperreal: A theory of Taylor series.
  1808 
  1809 
  1810 *** HOLCF ***
  1811 
  1812 * Discontinued special version of 'constdefs' (which used to support
  1813 continuous functions) in favor of the general Pure one with full
  1814 type-inference.
  1815 
  1816 * New simplification procedure for solving continuity conditions; it
  1817 is much faster on terms with many nested lambda abstractions (cubic
  1818 instead of exponential time).
  1819 
  1820 * New syntax for domain package: selector names are now optional.
  1821 Parentheses should be omitted unless argument is lazy, for example:
  1822 
  1823   domain 'a stream = cons "'a" (lazy "'a stream")
  1824 
  1825 * New command 'fixrec' for defining recursive functions with pattern
  1826 matching; defining multiple functions with mutual recursion is also
  1827 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1828 sinr, or any data constructor defined by the domain package. The given
  1829 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1830 syntax and examples.
  1831 
  1832 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1833 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1834 but the proof obligation additionally includes an admissibility
  1835 requirement. The packages generate instances of class cpo or pcpo,
  1836 with continuity and strictness theorems for Rep and Abs.
  1837 
  1838 * HOLCF: Many theorems have been renamed according to a more standard naming
  1839 scheme (INCOMPATIBILITY):
  1840 
  1841   foo_inject:  "foo$x = foo$y ==> x = y"
  1842   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1843   foo_less:    "(foo$x << foo$y) = (x << y)"
  1844   foo_strict:  "foo$UU = UU"
  1845   foo_defined: "... ==> foo$x ~= UU"
  1846   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1847 
  1848 
  1849 *** ZF ***
  1850 
  1851 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1852 including the First Isomorphism Theorem (on quotienting by the kernel
  1853 of a homomorphism).
  1854 
  1855 * ZF/Simplifier: install second copy of type solver that actually
  1856 makes use of TC rules declared to Isar proof contexts (or locales);
  1857 the old version is still required for ML proof scripts.
  1858 
  1859 
  1860 *** Cube ***
  1861 
  1862 * Converted to Isar theory format; use locales instead of axiomatic
  1863 theories.
  1864 
  1865 
  1866 *** ML ***
  1867 
  1868 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1869 for ||>, ||>>, |>>,
  1870 
  1871 * Pure/library.ML no longer defines its own option datatype, but uses
  1872 that of the SML basis, which has constructors NONE and SOME instead of
  1873 None and Some, as well as exception Option.Option instead of OPTION.
  1874 The functions the, if_none, is_some, is_none have been adapted
  1875 accordingly, while Option.map replaces apsome.
  1876 
  1877 * Pure/library.ML: the exception LIST has been given up in favour of
  1878 the standard exceptions Empty and Subscript, as well as
  1879 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1880 superceded by the standard hd and tl functions etc.
  1881 
  1882 A number of basic list functions are no longer exported to the ML
  1883 toplevel, as they are variants of predefined functions.  The following
  1884 suggests how one can translate existing code:
  1885 
  1886     rev_append xs ys = List.revAppend (xs, ys)
  1887     nth_elem (i, xs) = List.nth (xs, i)
  1888     last_elem xs = List.last xs
  1889     flat xss = List.concat xss
  1890     seq fs = List.app fs
  1891     partition P xs = List.partition P xs
  1892     mapfilter f xs = List.mapPartial f xs
  1893 
  1894 * Pure/library.ML: several combinators for linear functional
  1895 transformations, notably reverse application and composition:
  1896 
  1897   x |> f                f #> g
  1898   (x, y) |-> f          f #-> g
  1899 
  1900 * Pure/library.ML: introduced/changed precedence of infix operators:
  1901 
  1902   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1903   infix 2 ?;
  1904   infix 3 o oo ooo oooo;
  1905   infix 4 ~~ upto downto;
  1906 
  1907 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1908 infix operators.
  1909 
  1910 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1911 fold_map support linear functional transformations and nesting.  For
  1912 example:
  1913 
  1914   fold f [x1, ..., xN] y =
  1915     y |> f x1 |> ... |> f xN
  1916 
  1917   (fold o fold) f [xs1, ..., xsN] y =
  1918     y |> fold f xs1 |> ... |> fold f xsN
  1919 
  1920   fold f [x1, ..., xN] =
  1921     f x1 #> ... #> f xN
  1922 
  1923   (fold o fold) f [xs1, ..., xsN] =
  1924     fold f xs1 #> ... #> fold f xsN
  1925 
  1926 * Pure/library.ML: the following selectors on type 'a option are
  1927 available:
  1928 
  1929   the:               'a option -> 'a  (*partial*)
  1930   these:             'a option -> 'a  where 'a = 'b list
  1931   the_default: 'a -> 'a option -> 'a
  1932   the_list:          'a option -> 'a list
  1933 
  1934 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1935 basic operations for association lists, following natural argument
  1936 order; moreover the explicit equality predicate passed here avoids
  1937 potentially expensive polymorphic runtime equality checks.
  1938 The old functions may be expressed as follows:
  1939 
  1940   assoc = uncurry (AList.lookup (op =))
  1941   assocs = these oo AList.lookup (op =)
  1942   overwrite = uncurry (AList.update (op =)) o swap
  1943 
  1944 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1945 
  1946   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1947   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1948 
  1949 replacing make_keylist and keyfilter (occassionally used)
  1950 Naive rewrites:
  1951 
  1952   make_keylist = AList.make
  1953   keyfilter = AList.find (op =)
  1954 
  1955 * eq_fst and eq_snd now take explicit equality parameter, thus
  1956   avoiding eqtypes. Naive rewrites:
  1957 
  1958     eq_fst = eq_fst (op =)
  1959     eq_snd = eq_snd (op =)
  1960 
  1961 * Removed deprecated apl and apr (rarely used).
  1962   Naive rewrites:
  1963 
  1964     apl (n, op) =>>= curry op n
  1965     apr (op, m) =>>= fn n => op (n, m)
  1966 
  1967 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1968 provides a reasonably efficient light-weight implementation of sets as
  1969 lists.
  1970 
  1971 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1972 few new operations; existing lookup and update are now curried to
  1973 follow natural argument order (for use with fold etc.);
  1974 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1975 
  1976 * Pure/General: output via the Isabelle channels of
  1977 writeln/warning/error etc. is now passed through Output.output, with a
  1978 hook for arbitrary transformations depending on the print_mode
  1979 (cf. Output.add_mode -- the first active mode that provides a output
  1980 function wins).  Already formatted output may be embedded into further
  1981 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1982 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1983 accommodate easy composition of diagnostic messages etc.  Programmers
  1984 rarely need to care about Output.output or Output.raw at all, with
  1985 some notable exceptions: Output.output is required when bypassing the
  1986 standard channels (writeln etc.), or in token translations to produce
  1987 properly formatted results; Output.raw is required when capturing
  1988 already output material that will eventually be presented to the user
  1989 a second time.  For the default print mode, both Output.output and
  1990 Output.raw have no effect.
  1991 
  1992 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1993 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1994 cumulative results are displayed at the end of a batch session.
  1995 
  1996 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1997 replaced by File.platform_path and File.shell_path (with appropriate
  1998 hooks).  This provides a clean interface for unusual systems where the
  1999 internal and external process view of file names are different.
  2000 
  2001 * Pure: more efficient orders for basic syntactic entities: added
  2002 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2003 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2004 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2005 orders now -- potential INCOMPATIBILITY for code that depends on a
  2006 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2007 Library.sort_strings on result).
  2008 
  2009 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2010 fold_types traverse types/terms from left to right, observing natural
  2011 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2012 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2013 
  2014 * Pure: name spaces have been refined, with significant changes of the
  2015 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2016 to extern(_table).  The plain name entry path is superceded by a
  2017 general 'naming' context, which also includes the 'policy' to produce
  2018 a fully qualified name and external accesses of a fully qualified
  2019 name; NameSpace.extend is superceded by context dependent
  2020 Sign.declare_name.  Several theory and proof context operations modify
  2021 the naming context.  Especially note Theory.restore_naming and
  2022 ProofContext.restore_naming to get back to a sane state; note that
  2023 Theory.add_path is no longer sufficient to recover from
  2024 Theory.absolute_path in particular.
  2025 
  2026 * Pure: new flags short_names (default false) and unique_names
  2027 (default true) for controlling output of qualified names.  If
  2028 short_names is set, names are printed unqualified.  If unique_names is
  2029 reset, the name prefix is reduced to the minimum required to achieve
  2030 the original result when interning again, even if there is an overlap
  2031 with earlier declarations.
  2032 
  2033 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2034 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2035 (useful for printing error messages).  INCOMPATIBILITY.
  2036 
  2037 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2038 Theory.theory are now identified, referring to the universal
  2039 Context.theory (see Pure/context.ML).  Actual signature and theory
  2040 content is managed as theory data.  The old code and interfaces were
  2041 spread over many files and structures; the new arrangement introduces
  2042 considerable INCOMPATIBILITY to gain more clarity:
  2043 
  2044   Context -- theory management operations (name, identity, inclusion,
  2045     parents, ancestors, merge, etc.), plus generic theory data;
  2046 
  2047   Sign -- logical signature and syntax operations (declaring consts,
  2048     types, etc.), plus certify/read for common entities;
  2049 
  2050   Theory -- logical theory operations (stating axioms, definitions,
  2051     oracles), plus a copy of logical signature operations (consts,
  2052     types, etc.); also a few basic management operations (Theory.copy,
  2053     Theory.merge, etc.)
  2054 
  2055 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2056 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2057 for convenience -- they merely return the theory.
  2058 
  2059 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2060 
  2061 * Pure: the Isar proof context type is already defined early in Pure
  2062 as Context.proof (note that ProofContext.context and Proof.context are
  2063 aliases, where the latter is the preferred name).  This enables other
  2064 Isabelle components to refer to that type even before Isar is present.
  2065 
  2066 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2067 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2068 any of these kinds.  For example, Sign.intern typeK is now
  2069 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2070 Theory.hide_types.  Also note that former
  2071 Theory.hide_classes/types/consts are now
  2072 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2073 internalize their arguments!  INCOMPATIBILITY.
  2074 
  2075 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2076 datatype thmref (with constructors Name and NameSelection) instead of
  2077 plain string -- INCOMPATIBILITY;
  2078 
  2079 * Pure: cases produced by proof methods specify options, where NONE
  2080 means to remove case bindings -- INCOMPATIBILITY in
  2081 (RAW_)METHOD_CASES.
  2082 
  2083 * Pure: the following operations retrieve axioms or theorems from a
  2084 theory node or theory hierarchy, respectively:
  2085 
  2086   Theory.axioms_of: theory -> (string * term) list
  2087   Theory.all_axioms_of: theory -> (string * term) list
  2088   PureThy.thms_of: theory -> (string * thm) list
  2089   PureThy.all_thms_of: theory -> (string * thm) list
  2090 
  2091 * Pure: print_tac now outputs the goal through the trace channel.
  2092 
  2093 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2094 Reference Toplevel.debug (default false) controls detailed printing
  2095 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2096 controls execution profiling -- set to 1 for time and 2 for space
  2097 (both increase the runtime).
  2098 
  2099 * Isar session: The initial use of ROOT.ML is now always timed,
  2100 i.e. the log will show the actual process times, in contrast to the
  2101 elapsed wall-clock time that the outer shell wrapper produces.
  2102 
  2103 * Simplifier: improved handling of bound variables (nameless
  2104 representation, avoid allocating new strings).  Simprocs that invoke
  2105 the Simplifier recursively should use Simplifier.inherit_bounds to
  2106 avoid local name clashes.  Failure to do so produces warnings
  2107 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2108 for further details.
  2109 
  2110 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2111 bindings for all theorems stored within a given theory; this may help
  2112 in porting non-Isar theories to Isar ones, while keeping ML proof
  2113 scripts for the time being.
  2114 
  2115 * ML operator HTML.with_charset specifies the charset begin used for
  2116 generated HTML files.  For example:
  2117 
  2118   HTML.with_charset "utf-8" use_thy "Hebrew";
  2119   HTML.with_charset "utf-8" use_thy "Chinese";
  2120 
  2121 
  2122 *** System ***
  2123 
  2124 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2125 isabelle, isatool etc.).
  2126 
  2127 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2128 isatool doc, isatool mkdir, display_drafts etc.).
  2129 
  2130 * isatool usedir: option -f allows specification of the ML file to be
  2131 used by Isabelle; default is ROOT.ML.
  2132 
  2133 * New isatool version outputs the version identifier of the Isabelle
  2134 distribution being used.
  2135 
  2136 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2137 (containing Boolean satisfiability problems) into Isabelle/HOL
  2138 theories.
  2139 
  2140 
  2141 
  2142 New in Isabelle2004 (April 2004)
  2143 --------------------------------
  2144 
  2145 *** General ***
  2146 
  2147 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2148   Replaces linorder.ML.
  2149 
  2150 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2151   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2152   (\<a>...\<z>), are now considered normal letters, and can therefore
  2153   be used anywhere where an ASCII letter (a...zA...Z) has until
  2154   now. COMPATIBILITY: This obviously changes the parsing of some
  2155   terms, especially where a symbol has been used as a binder, say
  2156   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2157   as an identifier.  Fix it by inserting a space around former
  2158   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2159   existing theory and ML files.
  2160 
  2161 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2162 
  2163 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2164   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2165   a normal (but invisible) letter. For multiple letter subscripts repeat
  2166   \<^isub> like this: x\<^isub>1\<^isub>2.
  2167 
  2168 * Pure: There are now sub-/superscripts that can span more than one
  2169   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2170   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2171   superscript. The new control characters are not identifier parts.
  2172 
  2173 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2174   content of "..." to the latex file instead of \isacntrl... . The "..."
  2175   may consist of any printable characters excluding the end bracket >.
  2176 
  2177 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2178   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2179   declare constants "final", which prevents their being given a definition
  2180   later.  It is useful for constants whose behaviour is fixed axiomatically
  2181   rather than definitionally, such as the meta-logic connectives.
  2182 
  2183 * Pure: 'instance' now handles general arities with general sorts
  2184   (i.e. intersections of classes),
  2185 
  2186 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2187   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2188   It can be changed to alter the colors/layout of generated pages.
  2189 
  2190 
  2191 *** Isar ***
  2192 
  2193 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2194   cut_tac, subgoal_tac and thin_tac:
  2195   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2196     locales are no longer forced to write Isar proof scripts.
  2197     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2198     emulations.
  2199   - INCOMPATIBILITY: names of variables to be instantiated may no
  2200     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2201     This is consistent with the instantiation attribute "where".
  2202 
  2203 * Attributes "where" and "of":
  2204   - Now take type variables of instantiated theorem into account when reading
  2205     the instantiation string.  This fixes a bug that caused instantiated
  2206     theorems to have too special types in some circumstances.
  2207   - "where" permits explicit instantiations of type variables.
  2208 
  2209 * Calculation commands "moreover" and "also" no longer interfere with
  2210   current facts ("this"), admitting arbitrary combinations with "then"
  2211   and derived forms.
  2212 
  2213 * Locales:
  2214   - Goal statements involving the context element "includes" no longer
  2215     generate theorems with internal delta predicates (those ending on
  2216     "_axioms") in the premise.
  2217     Resolve particular premise with <locale>.intro to obtain old form.
  2218   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2219     specification and "includes" elements in goal statement.
  2220   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2221     [intro?] and [elim?] (respectively) by default.
  2222   - Experimental command for instantiation of locales in proof contexts:
  2223         instantiate <label>[<attrs>]: <loc>
  2224     Instantiates locale <loc> and adds all its theorems to the current context
  2225     taking into account their attributes.  Label and attrs are optional
  2226     modifiers, like in theorem declarations.  If present, names of
  2227     instantiated theorems are qualified with <label>, and the attributes
  2228     <attrs> are applied after any attributes these theorems might have already.
  2229       If the locale has assumptions, a chained fact of the form
  2230     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2231     are derived.  The command does not support old-style locales declared
  2232     with "locale (open)".
  2233       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2234 
  2235 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2236   (Isar) contexts.
  2237 
  2238 
  2239 *** HOL ***
  2240 
  2241 * Proof import: new image HOL4 contains the imported library from
  2242   the HOL4 system with about 2500 theorems. It is imported by
  2243   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2244   can be used like any other Isabelle image.  See
  2245   HOL/Import/HOL/README for more information.
  2246 
  2247 * Simplifier:
  2248   - Much improved handling of linear and partial orders.
  2249     Reasoners for linear and partial orders are set up for type classes
  2250     "linorder" and "order" respectively, and are added to the default simpset
  2251     as solvers.  This means that the simplifier can build transitivity chains
  2252     to solve goals from the assumptions.
  2253   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2254     of blast or auto after simplification become unnecessary because the goal
  2255     is solved by simplification already.
  2256 
  2257 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2258     all proved in axiomatic type classes for semirings, rings and fields.
  2259 
  2260 * Numerics:
  2261   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2262     now formalized using the Ring_and_Field theory mentioned above.
  2263   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2264     than before, because now they are set up once in a generic manner.
  2265   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2266     Look for the general versions in Ring_and_Field (and Power if they concern
  2267     exponentiation).
  2268 
  2269 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2270 
  2271 * Records:
  2272   - Record types are now by default printed with their type abbreviation
  2273     instead of the list of all field types. This can be configured via
  2274     the reference "print_record_type_abbr".
  2275   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2276     (not enabled by default).
  2277   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2278     EX x. x = sel r to True (not enabled by default).
  2279   - Tactic "record_split_simp_tac" to split and simplify records added.
  2280 
  2281 * 'specification' command added, allowing for definition by
  2282   specification.  There is also an 'ax_specification' command that
  2283   introduces the new constants axiomatically.
  2284 
  2285 * arith(_tac) is now able to generate counterexamples for reals as well.
  2286 
  2287 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2288 
  2289 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2290   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2291 
  2292 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2293   matrix theory to linear programming.
  2294 
  2295 * Unions and Intersections:
  2296   The latex output syntax of UN and INT has been changed
  2297   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2298   i.e. the index formulae has become a subscript.
  2299   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2300 
  2301 * Unions and Intersections over Intervals:
  2302   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2303   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2304   like in normal math, and corresponding versions for < and for intersection.
  2305 
  2306 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2307   lexicographic dictonary ordering has been added as "lexord".
  2308 
  2309 * ML: the legacy theory structures Int and List have been removed. They had
  2310   conflicted with ML Basis Library structures having the same names.
  2311 
  2312 * 'refute' command added to search for (finite) countermodels.  Only works
  2313   for a fragment of HOL.  The installation of an external SAT solver is
  2314   highly recommended.  See "HOL/Refute.thy" for details.
  2315 
  2316 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2317   formulae under an assignment of free variables to random values.
  2318   In contrast to 'refute', it can deal with inductive datatypes,
  2319   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2320   for examples.
  2321 
  2322 
  2323 *** HOLCF ***
  2324 
  2325 * Streams now come with concatenation and are part of the HOLCF image
  2326 
  2327 
  2328 
  2329 New in Isabelle2003 (May 2003)
  2330 ------------------------------
  2331 
  2332 *** General ***
  2333 
  2334 * Provers/simplifier:
  2335 
  2336   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2337     Assumptions are now subject to complete mutual simplification,
  2338     not just from left to right. The simplifier now preserves
  2339     the order of assumptions.
  2340 
  2341     Potential INCOMPATIBILITY:
  2342 
  2343     -- simp sometimes diverges where the old version did
  2344        not, e.g. invoking simp on the goal
  2345 
  2346         [| P (f x); y = x; f x = f y |] ==> Q
  2347 
  2348        now gives rise to the infinite reduction sequence
  2349 
  2350         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2351 
  2352        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2353        kind of problem.
  2354 
  2355     -- Tactics combining classical reasoner and simplification (such as auto)
  2356        are also affected by this change, because many of them rely on
  2357        simp. They may sometimes diverge as well or yield a different numbers
  2358        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2359        in case of problems. Sometimes subsequent calls to the classical
  2360        reasoner will fail because a preceeding call to the simplifier too
  2361        eagerly simplified the goal, e.g. deleted redundant premises.
  2362 
  2363   - The simplifier trace now shows the names of the applied rewrite rules
  2364 
  2365   - You can limit the number of recursive invocations of the simplifier
  2366     during conditional rewriting (where the simplifie tries to solve the
  2367     conditions before applying the rewrite rule):
  2368     ML "simp_depth_limit := n"
  2369     where n is an integer. Thus you can force termination where previously
  2370     the simplifier would diverge.
  2371 
  2372   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2373 
  2374   - No longer aborts on failed congruence proof.  Instead, the
  2375     congruence is ignored.
  2376 
  2377 * Pure: New generic framework for extracting programs from constructive
  2378   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2379   as HOL/Extraction for some case studies.
  2380 
  2381 * Pure: The main goal of the proof state is no longer shown by default, only
  2382 the subgoals. This behaviour is controlled by a new flag.
  2383    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2384 (ML: Proof.show_main_goal).
  2385 
  2386 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2387 rules whose conclusion matches subgoal 1:
  2388       PG menu: Isabelle/Isar -> Show me -> matching rules
  2389 The rules are ordered by how closely they match the subgoal.
  2390 In particular, rules that solve a subgoal outright are displayed first
  2391 (or rather last, the way they are printed).
  2392 (ML: ProofGeneral.print_intros())
  2393 
  2394 * Pure: New flag trace_unify_fail causes unification to print
  2395 diagnostic information (PG: in trace buffer) when it fails. This is
  2396 useful for figuring out why single step proofs like rule, erule or
  2397 assumption failed.
  2398 
  2399 * Pure: Locale specifications now produce predicate definitions
  2400 according to the body of text (covering assumptions modulo local
  2401 definitions); predicate "loc_axioms" covers newly introduced text,
  2402 while "loc" is cumulative wrt. all included locale expressions; the
  2403 latter view is presented only on export into the global theory
  2404 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2405 on the old view without predicates;
  2406 
  2407 * Pure: predefined locales "var" and "struct" are useful for sharing
  2408 parameters (as in CASL, for example); just specify something like
  2409 ``var x + var y + struct M'' as import;
  2410 
  2411 * Pure: improved thms_containing: proper indexing of facts instead of
  2412 raw theorems; check validity of results wrt. current name space;
  2413 include local facts of proof configuration (also covers active
  2414 locales), cover fixed variables in index; may use "_" in term
  2415 specification; an optional limit for the number of printed facts may
  2416 be given (the default is 40);
  2417 
  2418 * Pure: disallow duplicate fact bindings within new-style theory files
  2419 (batch-mode only);
  2420 
  2421 * Provers: improved induct method: assumptions introduced by case
  2422 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2423 the goal statement); "foo" still refers to all facts collectively;
  2424 
  2425 * Provers: the function blast.overloaded has been removed: all constants
  2426 are regarded as potentially overloaded, which improves robustness in exchange
  2427 for slight decrease in efficiency;
  2428 
  2429 * Provers/linorder: New generic prover for transitivity reasoning over
  2430 linear orders.  Note: this prover is not efficient!
  2431 
  2432 * Isar: preview of problems to finish 'show' now produce an error
  2433 rather than just a warning (in interactive mode);
  2434 
  2435 
  2436 *** HOL ***
  2437 
  2438 * arith(_tac)
  2439 
  2440  - Produces a counter example if it cannot prove a goal.
  2441    Note that the counter example may be spurious if the goal is not a formula
  2442    of quantifier-free linear arithmetic.
  2443    In ProofGeneral the counter example appears in the trace buffer.
  2444 
  2445  - Knows about div k and mod k where k is a numeral of type nat or int.
  2446 
  2447  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2448    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2449    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2450 
  2451 * simp's arithmetic capabilities have been enhanced a bit: it now
  2452 takes ~= in premises into account (by performing a case split);
  2453 
  2454 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2455 are distributed over a sum of terms;
  2456 
  2457 * New tactic "trans_tac" and method "trans" instantiate
  2458 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2459 "<=", "<" and "=").
  2460 
  2461 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2462 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2463 
  2464 * 'typedef' command has new option "open" to suppress the set
  2465 definition;
  2466 
  2467 * functions Min and Max on finite sets have been introduced (theory
  2468 Finite_Set);
  2469 
  2470 * attribute [symmetric] now works for relations as well; it turns
  2471 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2472 
  2473 * induct over a !!-quantified statement (say !!x1..xn):
  2474   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2475 
  2476 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2477 %x. None. Warning: empty_def now refers to the previously hidden definition
  2478 of the empty set.
  2479 
  2480 * Algebra: formalization of classical algebra.  Intended as base for
  2481 any algebraic development in Isabelle.  Currently covers group theory
  2482 (up to Sylow's theorem) and ring theory (Universal Property of
  2483 Univariate Polynomials).  Contributions welcome;
  2484 
  2485 * GroupTheory: deleted, since its material has been moved to Algebra;
  2486 
  2487 * Complex: new directory of the complex numbers with numeric constants,
  2488 nonstandard complex numbers, and some complex analysis, standard and
  2489 nonstandard (Jacques Fleuriot);
  2490 
  2491 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2492 
  2493 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2494 Fleuriot);
  2495 
  2496 * Real/HahnBanach: updated and adapted to locales;
  2497 
  2498 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2499 Gray and Kramer);
  2500 
  2501 * UNITY: added the Meier-Sanders theory of progress sets;
  2502 
  2503 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2504 as abstract algorithms, instantiated to the JVM;
  2505 
  2506 * Bali: Java source language formalization. Type system, operational
  2507 semantics, axiomatic semantics. Supported language features:
  2508 classes, interfaces, objects,virtual methods, static methods,
  2509 static/instance fields, arrays, access modifiers, definite
  2510 assignment, exceptions.
  2511 
  2512 
  2513 *** ZF ***
  2514 
  2515 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2516 universe, etc.);
  2517 
  2518 * Main ZF: virtually all theories converted to new-style format;
  2519 
  2520 
  2521 *** ML ***
  2522 
  2523 * Pure: Tactic.prove provides sane interface for internal proofs;
  2524 omits the infamous "standard" operation, so this is more appropriate
  2525 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2526 
  2527 * Pure: improved error reporting of simprocs;
  2528 
  2529 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2530 up simprocs;
  2531 
  2532 
  2533 *** Document preparation ***
  2534 
  2535 * uses \par instead of \\ for line breaks in theory text. This may
  2536 shift some page breaks in large documents. To get the old behaviour
  2537 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2538 
  2539 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2540 other packages
  2541 
  2542 * \<euro> now needs package babel/greek instead of marvosym (which
  2543 broke \Rightarrow)
  2544 
  2545 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2546 textcomp package)
  2547 
  2548 
  2549 
  2550 New in Isabelle2002 (March 2002)
  2551 --------------------------------
  2552 
  2553 *** Document preparation ***
  2554 
  2555 * greatly simplified document preparation setup, including more
  2556 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2557 instructive isatool mkdir; users should basically be able to get
  2558 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2559 users may run a separate document processing stage manually like this:
  2560 "isatool usedir -D output HOL Test && isatool document Test/output";
  2561 
  2562 * theory dependency graph may now be incorporated into documents;
  2563 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2564 with \includegraphics of LaTeX;
  2565 
  2566 * proper spacing of consecutive markup elements, especially text
  2567 blocks after section headings;
  2568 
  2569 * support bold style (for single symbols only), input syntax is like
  2570 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2571 
  2572 * \<bullet> is now output as bold \cdot by default, which looks much
  2573 better in printed text;
  2574 
  2575 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2576 note that these symbols are currently unavailable in Proof General /
  2577 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2578 
  2579 * isatool latex no longer depends on changed TEXINPUTS, instead
  2580 isatool document copies the Isabelle style files to the target
  2581 location;
  2582 
  2583 
  2584 *** Isar ***
  2585 
  2586 * Pure/Provers: improved proof by cases and induction;
  2587   - 'case' command admits impromptu naming of parameters (such as
  2588     "case (Suc n)");
  2589   - 'induct' method divinates rule instantiation from the inductive
  2590     claim; no longer requires excessive ?P bindings for proper
  2591     instantiation of cases;
  2592   - 'induct' method properly enumerates all possibilities of set/type
  2593     rules; as a consequence facts may be also passed through *type*
  2594     rules without further ado;
  2595   - 'induct' method now derives symbolic cases from the *rulified*
  2596     rule (before it used to rulify cases stemming from the internal
  2597     atomized version); this means that the context of a non-atomic
  2598     statement becomes is included in the hypothesis, avoiding the
  2599     slightly cumbersome show "PROP ?case" form;
  2600   - 'induct' may now use elim-style induction rules without chaining
  2601     facts, using ``missing'' premises from the goal state; this allows
  2602     rules stemming from inductive sets to be applied in unstructured
  2603     scripts, while still benefitting from proper handling of non-atomic
  2604     statements; NB: major inductive premises need to be put first, all
  2605     the rest of the goal is passed through the induction;
  2606   - 'induct' proper support for mutual induction involving non-atomic
  2607     rule statements (uses the new concept of simultaneous goals, see
  2608     below);
  2609   - append all possible rule selections, but only use the first
  2610     success (no backtracking);
  2611   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2612   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2613   - added 'print_induct_rules' (covered by help item in recent Proof
  2614     General versions);
  2615   - moved induct/cases attributes to Pure, methods to Provers;
  2616   - generic method setup instantiated for FOL and HOL;
  2617 
  2618 * Pure: support multiple simultaneous goal statements, for example
  2619 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2620 meta-level mechanism, this acts as if several individual goals had
  2621 been stated separately; in particular common proof methods need to be
  2622 repeated in order to cover all claims; note that a single elimination
  2623 step is *not* sufficient to establish the two conjunctions, so this
  2624 fails:
  2625 
  2626   assume "A & B" then have A and B ..   (*".." fails*)
  2627 
  2628 better use "obtain" in situations as above; alternative refer to
  2629 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2630 
  2631 * Pure: proper integration with ``locales''; unlike the original
  2632 version by Florian Kammller, Isar locales package high-level proof
  2633 contexts rather than raw logical ones (e.g. we admit to include
  2634 attributes everywhere); operations on locales include merge and
  2635 rename; support for implicit arguments (``structures''); simultaneous
  2636 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2637 some examples;
  2638 
  2639 * Pure: the following commands have been ``localized'', supporting a
  2640 target locale specification "(in name)": 'lemma', 'theorem',
  2641 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2642 stored both within the locale and at the theory level (exported and
  2643 qualified by the locale name);
  2644 
  2645 * Pure: theory goals may now be specified in ``long'' form, with
  2646 ad-hoc contexts consisting of arbitrary locale elements. for example
  2647 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2648 definitions may be given, too); the result is a meta-level rule with
  2649 the context elements being discharged in the obvious way;
  2650 
  2651 * Pure: new proof command 'using' allows to augment currently used
  2652 facts after a goal statement ('using' is syntactically analogous to
  2653 'apply', but acts on the goal's facts only); this allows chained facts
  2654 to be separated into parts given before and after a claim, as in
  2655 ``from a and b have C using d and e <proof>'';
  2656 
  2657 * Pure: renamed "antecedent" case to "rule_context";
  2658 
  2659 * Pure: new 'judgment' command records explicit information about the
  2660 object-logic embedding (used by several tools internally); no longer
  2661 use hard-wired "Trueprop";
  2662 
  2663 * Pure: added 'corollary' command;
  2664 
  2665 * Pure: fixed 'token_translation' command;
  2666 
  2667 * Pure: removed obsolete 'exported' attribute;
  2668 
  2669 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2670 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2671 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2672 
  2673 * Pure: method 'atomize' presents local goal premises as object-level
  2674 statements (atomic meta-level propositions); setup controlled via
  2675 rewrite rules declarations of 'atomize' attribute; example
  2676 application: 'induct' method with proper rule statements in improper
  2677 proof *scripts*;
  2678 
  2679 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2680 now consider the syntactic context of assumptions, giving a better
  2681 chance to get type-inference of the arguments right (this is
  2682 especially important for locales);
  2683 
  2684 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2685 mode;
  2686 
  2687 * Pure/obtain: the formal conclusion "thesis", being marked as
  2688 ``internal'', may no longer be reference directly in the text;
  2689 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2690 situations;
  2691 
  2692 * Pure: generic 'sym' attribute which declares a rule both as pure
  2693 'elim?' and for the 'symmetric' operation;
  2694 
  2695 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2696 text; the fixed correlation with particular command syntax has been
  2697 discontinued;
  2698 
  2699 * Pure: new method 'rules' is particularly well-suited for proof
  2700 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2701 but often produces more compact proof terms with less detours;
  2702 
  2703 * Pure/Provers/classical: simplified integration with pure rule
  2704 attributes and methods; the classical "intro?/elim?/dest?"
  2705 declarations coincide with the pure ones; the "rule" method no longer
  2706 includes classically swapped intros; "intro" and "elim" methods no
  2707 longer pick rules from the context; also got rid of ML declarations
  2708 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2709 INCOMPATIBILITY;
  2710 
  2711 * Provers/classical: attribute 'swapped' produces classical inversions
  2712 of introduction rules;
  2713 
  2714 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2715 rules instead of full simplifier context; 'iff' attribute handles
  2716 conditional rules;
  2717 
  2718 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2719 
  2720 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2721 "(permissive)" option to recover old behavior;
  2722 
  2723 * HOL: 'inductive' no longer features separate (collective) attributes
  2724 for 'intros' (was found too confusing);
  2725 
  2726 * HOL: properly declared induction rules less_induct and
  2727 wf_induct_rule;
  2728 
  2729 
  2730 *** HOL ***
  2731 
  2732 * HOL: moved over to sane numeral syntax; the new policy is as
  2733 follows:
  2734 
  2735   - 0 and 1 are polymorphic constants, which are defined on any
  2736   numeric type (nat, int, real etc.);
  2737 
  2738   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2739   binary representation internally;
  2740 
  2741   - type nat has special constructor Suc, and generally prefers Suc 0
  2742   over 1::nat and Suc (Suc 0) over 2::nat;
  2743 
  2744 This change may cause significant problems of INCOMPATIBILITY; here
  2745 are some hints on converting existing sources:
  2746 
  2747   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2748   entities, so expressions involving "-" (unary or binary minus) need
  2749   to be spaced properly;
  2750 
  2751   - existing occurrences of "1" may need to be constraint "1::nat" or
  2752   even replaced by Suc 0; similar for old "2";
  2753 
  2754   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2755 
  2756   - remove all special provisions on numerals in proofs;
  2757 
  2758 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2759 representation (depends on bin_arith_simps in the default context);
  2760 
  2761 * HOL: symbolic syntax for x^2 (numeral 2);
  2762 
  2763 * HOL: the class of all HOL types is now called "type" rather than
  2764 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2765 in axclass/classes, instance/arities, and (usually rare) occurrences
  2766 in typings (of consts etc.); internally the class is called
  2767 "HOL.type", ML programs should refer to HOLogic.typeS;
  2768 
  2769 * HOL/record package improvements:
  2770   - new derived operations "fields" to build a partial record section,
  2771     "extend" to promote a fixed record to a record scheme, and
  2772     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2773     declared as simp by default;
  2774   - shared operations ("more", "fields", etc.) now need to be always
  2775     qualified) --- potential INCOMPATIBILITY;
  2776   - removed "make_scheme" operations (use "make" with "extend") --
  2777     INCOMPATIBILITY;
  2778   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2779   - provides cases/induct rules for use with corresponding Isar
  2780     methods (for concrete records, record schemes, concrete more
  2781     parts, and schematic more parts -- in that order);
  2782   - internal definitions directly based on a light-weight abstract
  2783     theory of product types over typedef rather than datatype;
  2784 
  2785 * HOL: generic code generator for generating executable ML code from
  2786 specifications; specific support for HOL constructs such as inductive
  2787 datatypes and sets, as well as recursive functions; can be invoked
  2788 via 'generate_code' theory section;
  2789 
  2790 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2791 
  2792 * HOL: consolidated and renamed several theories.  In particular:
  2793         Ord.thy has been absorbed into HOL.thy
  2794         String.thy has been absorbed into List.thy
  2795 
  2796 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2797 (beware of argument permutation!);
  2798 
  2799 * HOL: linorder_less_split superseded by linorder_cases;
  2800 
  2801 * HOL/List: "nodups" renamed to "distinct";
  2802 
  2803 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2804 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2805   - Ex_def has changed, now need to use some_eq_ex
  2806 
  2807 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2808 in this (rare) case use:
  2809 
  2810   delSWrapper "split_all_tac"
  2811   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2812 
  2813 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2814 MAY FAIL;
  2815 
  2816 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2817 Isabelle's type classes, ^ on functions and relations has too general
  2818 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2819 necessary to attach explicit type constraints;
  2820 
  2821 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2822 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2823 renamed accordingly (eg "compI" -> "rel_compI").
  2824 
  2825 * HOL: syntax translations now work properly with numerals and records
  2826 expressions;
  2827 
  2828 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2829 of "lam" -- INCOMPATIBILITY;
  2830 
  2831 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2832 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2833 renamed "Product_Type.unit";
  2834 
  2835 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2836 
  2837 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2838 the "cases" method);
  2839 
  2840 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2841 Florian Kammller);
  2842 
  2843 * HOL/IMP: updated and converted to new-style theory format; several
  2844 parts turned into readable document, with proper Isar proof texts and
  2845 some explanations (by Gerwin Klein);
  2846 
  2847 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2848 
  2849 * HOL-Hyperreal is now a logic image;
  2850 
  2851 
  2852 *** HOLCF ***
  2853 
  2854 * Isar: consts/constdefs supports mixfix syntax for continuous
  2855 operations;
  2856 
  2857 * Isar: domain package adapted to new-style theory format, e.g. see
  2858 HOLCF/ex/Dnat.thy;
  2859 
  2860 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2861 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2862 lift.induct_tac, always use UU instead of Undef;
  2863 
  2864 * HOLCF/IMP: updated and converted to new-style theory;
  2865 
  2866 
  2867 *** ZF ***
  2868 
  2869 * Isar: proper integration of logic-specific tools and packages,
  2870 including theory commands '(co)inductive', '(co)datatype',
  2871 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2872 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2873 
  2874 * theory Main no longer includes AC; for the Axiom of Choice, base
  2875 your theory on Main_ZFC;
  2876 
  2877 * the integer library now covers quotients and remainders, with many
  2878 laws relating division to addition, multiplication, etc.;
  2879 
  2880 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2881 typeless version of the formalism;
  2882 
  2883 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2884 format;
  2885 
  2886 * ZF/Induct: new directory for examples of inductive definitions,
  2887 including theory Multiset for multiset orderings; converted to
  2888 new-style theory format;
  2889 
  2890 * ZF: many new theorems about lists, ordinals, etc.;
  2891 
  2892 
  2893 *** General ***
  2894 
  2895 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2896 variable proof controls level of detail: 0 = no proofs (only oracle
  2897 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2898 also ref manual for further ML interfaces;
  2899 
  2900 * Pure/axclass: removed obsolete ML interface
  2901 goal_subclass/goal_arity;
  2902 
  2903 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2904 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2905 separate tokens, so expressions involving minus need to be spaced
  2906 properly;
  2907 
  2908 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2909 rather than "infixl" or "infixr";
  2910 
  2911 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2912 sort constraint specifications in type inference; e.g. "x::_::foo"
  2913 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2914 type variable);
  2915 
  2916 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2917 control output of nested => (types); the default behavior is
  2918 "type_brackets";
  2919 
  2920 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2921 tokens into AST constants;
  2922 
  2923 * Pure/syntax: prefer later declarations of translations and print
  2924 translation functions; potential INCOMPATIBILITY: need to reverse
  2925 multiple declarations for same syntax element constant;
  2926 
  2927 * Pure/show_hyps reset by default (in accordance to existing Isar
  2928 practice);
  2929 
  2930 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2931 addSafter;
  2932 
  2933 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2934 as well;
  2935 
  2936 * system: tested support for MacOS X; should be able to get Isabelle +
  2937 Proof General to work in a plain Terminal after installing Poly/ML
  2938 (e.g. from the Isabelle distribution area) and GNU bash alone
  2939 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2940 support requires further installations, e.g. from
  2941 http://fink.sourceforge.net/);
  2942 
  2943 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2944 
  2945 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2946 of 40 MB), cf. ML_OPTIONS;
  2947 
  2948 * system: Proof General keywords specification is now part of the
  2949 Isabelle distribution (see etc/isar-keywords.el);
  2950 
  2951 * system: support for persistent Proof General sessions (refrain from
  2952 outdating all loaded theories on startup); user may create writable
  2953 logic images like this: ``isabelle -q HOL Test'';
  2954 
  2955 * system: smart selection of Isabelle process versus Isabelle
  2956 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2957 run both "isabelle" and "Isabelle" even if file names are badly
  2958 damaged (executable inspects the case of the first letter of its own
  2959 name); added separate "isabelle-process" and "isabelle-interface";
  2960 
  2961 * system: refrain from any attempt at filtering input streams; no
  2962 longer support ``8bit'' encoding of old isabelle font, instead proper
  2963 iso-latin characters may now be used; the related isatools
  2964 "symbolinput" and "nonascii" have disappeared as well;
  2965 
  2966 * system: removed old "xterm" interface (the print modes "xterm" and
  2967 "xterm_color" are still available for direct use in a suitable
  2968 terminal);
  2969 
  2970 
  2971 
  2972 New in Isabelle99-2 (February 2001)
  2973 -----------------------------------
  2974 
  2975 *** Overview of INCOMPATIBILITIES ***
  2976 
  2977 * HOL: please note that theories in the Library and elsewhere often use the
  2978 new-style (Isar) format; to refer to their theorems in an ML script you must
  2979 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2980 
  2981 * HOL: inductive package no longer splits induction rule aggressively,
  2982 but only as far as specified by the introductions given; the old
  2983 format may be recovered via ML function complete_split_rule or attribute
  2984 'split_rule (complete)';
  2985 
  2986 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2987 gfp_Tarski to gfp_unfold;
  2988 
  2989 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2990 
  2991 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2992 relation); infix "^^" has been renamed "``"; infix "``" has been
  2993 renamed "`"; "univalent" has been renamed "single_valued";
  2994 
  2995 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2996 operation;
  2997 
  2998 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2999 
  3000 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3001 
  3002 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3003 consequence, it is no longer monotonic wrt. the local goal context
  3004 (which is now passed through the inductive cases);
  3005 
  3006 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3007 \<gg> to \<ggreater>;
  3008 
  3009 
  3010 *** Document preparation ***
  3011 
  3012 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3013 available: are "it" for near math-mode best-style output, "sl" for
  3014 slanted text style, and "tt" for plain type-writer; if no
  3015 \isabellestyle command is given, output is according to slanted
  3016 type-writer);
  3017 
  3018 * support sub/super scripts (for single symbols only), input syntax is
  3019 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3020 
  3021 * some more standard symbols; see Appendix A of the system manual for
  3022 the complete list of symbols defined in isabellesym.sty;
  3023 
  3024 * improved isabelle style files; more abstract symbol implementation
  3025 (should now use \isamath{...} and \isatext{...} in custom symbol
  3026 definitions);
  3027 
  3028 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3029 state; Note that presentation of goal states does not conform to
  3030 actual human-readable proof documents.  Please do not include goal
  3031 states into document output unless you really know what you are doing!
  3032 
  3033 * proper indentation of antiquoted output with proportional LaTeX
  3034 fonts;
  3035 
  3036 * no_document ML operator temporarily disables LaTeX document
  3037 generation;
  3038 
  3039 * isatool unsymbolize tunes sources for plain ASCII communication;
  3040 
  3041 
  3042 *** Isar ***
  3043 
  3044 * Pure: Isar now suffers initial goal statements to contain unbound
  3045 schematic variables (this does not conform to actual readable proof
  3046 documents, due to unpredictable outcome and non-compositional proof
  3047 checking); users who know what they are doing may use schematic goals
  3048 for Prolog-style synthesis of proven results;
  3049 
  3050 * Pure: assumption method (an implicit finishing) now handles actual
  3051 rules as well;
  3052 
  3053 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3054 initial goal, declare "that" only as Pure intro (only for single
  3055 steps); the "that" rule assumption may now be involved in implicit
  3056 finishing, thus ".." becomes a feasible for trivial obtains;
  3057 
  3058 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3059 instance proofs may be performed by "..";
  3060 
  3061 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3062 statements as well;
  3063 
  3064 * Pure: more robust selection of calculational rules;
  3065 
  3066 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3067 rule (as well as the assumption rule);
  3068 
  3069 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3070 lemmas, using the graph browser tool;
  3071 
  3072 * Pure: predict failure of "show" in interactive mode;
  3073 
  3074 * Pure: 'thms_containing' now takes actual terms as arguments;
  3075 
  3076 * HOL: improved method 'induct' --- now handles non-atomic goals
  3077 (potential INCOMPATIBILITY); tuned error handling;
  3078 
  3079 * HOL: cases and induct rules now provide explicit hints about the
  3080 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3081 any remaining facts are inserted into the goal verbatim;
  3082 
  3083 * HOL: local contexts (aka cases) may now contain term bindings as
  3084 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3085 the result to be shown in each case;
  3086 
  3087 * HOL: added 'recdef_tc' command;
  3088 
  3089 * isatool convert assists in eliminating legacy ML scripts;
  3090 
  3091 
  3092 *** HOL ***
  3093 
  3094 * HOL/Library: a collection of generic theories to be used together
  3095 with main HOL; the theory loader path already includes this directory
  3096 by default; the following existing theories have been moved here:
  3097 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3098 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3099 
  3100 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3101 modelling and verification task performed in Isabelle/HOL +
  3102 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3103 
  3104 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3105 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3106 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3107 'domain', this makes the theory consistent with mathematical
  3108 literature;
  3109 
  3110 * HOL basics: added overloaded operations "inverse" and "divide"
  3111 (infix "/"), syntax for generic "abs" operation, generic summation
  3112 operator \<Sum>;
  3113 
  3114 * HOL/typedef: simplified package, provide more useful rules (see also
  3115 HOL/subset.thy);
  3116 
  3117 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3118 now expressed as a proper nested rule (old-style tactic scripts may
  3119 require atomize_strip_tac to cope with non-atomic premises);
  3120 
  3121 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3122 to "split_conv" (old name still available for compatibility);
  3123 
  3124 * HOL: improved concrete syntax for strings (e.g. allows translation
  3125 rules with string literals);
  3126 
  3127 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3128  and Fleuriot's mechanization of analysis, including the transcendental
  3129  functions for the reals;
  3130 
  3131 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3132 
  3133 
  3134 *** CTT ***
  3135 
  3136 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3137 "lam" is displayed as TWO lambda-symbols
  3138 
  3139 * CTT: theory Main now available, containing everything (that is, Bool
  3140 and Arith);
  3141 
  3142 
  3143 *** General ***
  3144 
  3145 * Pure: the Simplifier has been implemented properly as a derived rule
  3146 outside of the actual kernel (at last!); the overall performance
  3147 penalty in practical applications is about 50%, while reliability of
  3148 the Isabelle inference kernel has been greatly improved;
  3149 
  3150 * print modes "brackets" and "no_brackets" control output of nested =>
  3151 (types) and ==> (props); the default behaviour is "brackets";
  3152 
  3153 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3154 as assumptions as well;
  3155 
  3156 * system: support Poly/ML 4.0;
  3157 
  3158 * system: isatool install handles KDE version 1 or 2;
  3159 
  3160 
  3161 
  3162 New in Isabelle99-1 (October 2000)
  3163 ----------------------------------
  3164 
  3165 *** Overview of INCOMPATIBILITIES ***
  3166 
  3167 * HOL: simplification of natural numbers is much changed; to partly
  3168 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3169 issue the following ML commands:
  3170 
  3171   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3172   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3173 
  3174 * HOL: simplification no longer dives into case-expressions; this is
  3175 controlled by "t.weak_case_cong" for each datatype t;
  3176 
  3177 * HOL: nat_less_induct renamed to less_induct;
  3178 
  3179 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3180 fixsome to patch .thy and .ML sources automatically;
  3181 
  3182   select_equality  -> some_equality
  3183   select_eq_Ex     -> some_eq_ex
  3184   selectI2EX       -> someI2_ex
  3185   selectI2         -> someI2
  3186   selectI          -> someI
  3187   select1_equality -> some1_equality
  3188   Eps_sym_eq       -> some_sym_eq_trivial
  3189   Eps_eq           -> some_eq_trivial
  3190 
  3191 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3192 
  3193 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3194 instead);
  3195 
  3196 * HOL: the recursion equations generated by 'recdef' are now called
  3197 f.simps instead of f.rules;
  3198 
  3199 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3200 
  3201 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3202 sometimes be needed;
  3203 
  3204 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3205 
  3206 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3207 
  3208 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3209 product is now "<*>" instead of "Times"; the lexicographic product is
  3210 now "<*lex*>" instead of "**";
  3211 
  3212 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3213 of main HOL, but was unused); better use HOL's datatype package;
  3214 
  3215 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3216 the old syntax may be recovered as follows:
  3217 
  3218   syntax (symbols)
  3219     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3220       (infixl "\\<oplus>" 100)
  3221 
  3222 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3223 
  3224 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3225 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3226 internally;
  3227 
  3228 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3229 changed from A/r to A//r;
  3230 
  3231 * ZF: new treatment of arithmetic (nat & int) may break some old
  3232 proofs;
  3233 
  3234 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3235 rulify -> rule_format, elimify -> elim_format, ...);
  3236 
  3237 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3238 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3239 should have to change intro!! to intro? only); replaced "delrule" by
  3240 "rule del";
  3241 
  3242 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3243 
  3244 * Provers: strengthened force_tac by using new first_best_tac;
  3245 
  3246 * LaTeX document preparation: several changes of isabelle.sty (see
  3247 lib/texinputs);
  3248 
  3249 
  3250 *** Document preparation ***
  3251 
  3252 * formal comments (text blocks etc.) in new-style theories may now
  3253 contain antiquotations of thm/prop/term/typ/text to be presented
  3254 according to latex print mode; concrete syntax is like this:
  3255 @{term[show_types] "f(x) = a + x"};
  3256 
  3257 * isatool mkdir provides easy setup of Isabelle session directories,
  3258 including proper document sources;
  3259 
  3260 * generated LaTeX sources are now deleted after successful run
  3261 (isatool document -c); may retain a copy somewhere else via -D option
  3262 of isatool usedir;
  3263 
  3264 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3265 style files, achieving self-contained LaTeX sources and simplifying
  3266 LaTeX debugging;
  3267 
  3268 * old-style theories now produce (crude) LaTeX output as well;
  3269 
  3270 * browser info session directories are now self-contained (may be put
  3271 on WWW server seperately); improved graphs of nested sessions; removed
  3272 graph for 'all sessions';
  3273 
  3274 * several improvements in isabelle style files; \isabellestyle{it}
  3275 produces fake math mode output; \isamarkupheader is now \section by
  3276 default; see lib/texinputs/isabelle.sty etc.;
  3277 
  3278 
  3279 *** Isar ***
  3280 
  3281 * Isar/Pure: local results and corresponding term bindings are now
  3282 subject to Hindley-Milner polymorphism (similar to ML); this
  3283 accommodates incremental type-inference very nicely;
  3284 
  3285 * Isar/Pure: new derived language element 'obtain' supports
  3286 generalized existence reasoning;
  3287 
  3288 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3289 support accumulation of results, without applying any rules yet;
  3290 useful to collect intermediate results without explicit name
  3291 references, and for use with transitivity rules with more than 2
  3292 premises;
  3293 
  3294 * Isar/Pure: scalable support for case-analysis type proofs: new
  3295 'case' language element refers to local contexts symbolically, as
  3296 produced by certain proof methods; internally, case names are attached
  3297 to theorems as "tags";
  3298 
  3299 * Isar/Pure: theory command 'hide' removes declarations from
  3300 class/type/const name spaces;
  3301 
  3302 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3303 indicate potential overloading;
  3304 
  3305 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3306 
  3307 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3308 "{a,b,c}" instead of {a,b,c};
  3309 
  3310 * Isar/Pure now provides its own version of intro/elim/dest
  3311 attributes; useful for building new logics, but beware of confusion
  3312 with the version in Provers/classical;
  3313 
  3314 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3315 case name 'antecedent';
  3316 
  3317 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3318 to the current context is now done automatically);
  3319 
  3320 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3321 for definining proof methods in ML;
  3322 
  3323 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3324 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3325 most cases, one should have to change intro!! to intro? only);
  3326 replaced "delrule" by "rule del";
  3327 
  3328 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3329 'symmetric' attribute (the latter supercedes [RS sym]);
  3330 
  3331 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3332 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3333 well (including splits);
  3334 
  3335 * Isar/Provers: Simplifier and Classical methods now support all kind
  3336 of modifiers used in the past, including 'cong', 'iff', etc.
  3337 
  3338 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3339 of Simplifier and Classical reasoner);
  3340 
  3341 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3342 now support named cases; major packages (inductive, datatype, primrec,
  3343 recdef) support case names and properly name parameters;
  3344 
  3345 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3346 monotonicity conditions are extracted to be proven at end of
  3347 calculations;
  3348 
  3349 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3350 method anyway;
  3351 
  3352 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3353 split_if split_if_asm; datatype package provides theorems foo.splits =
  3354 foo.split foo.split_asm for each datatype;
  3355 
  3356 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3357 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3358 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3359 use "(cases (simplified))" method in proper proof texts);
  3360 
  3361 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3362 
  3363 * Isar: names of theorems etc. may be natural numbers as well;
  3364 
  3365 * Isar: 'pr' command: optional arguments for goals_limit and
  3366 ProofContext.prems_limit; no longer prints theory contexts, but only
  3367 proof states;
  3368 
  3369 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3370 additional print modes to be specified; e.g. "pr(latex)" will print
  3371 proof state according to the Isabelle LaTeX style;
  3372 
  3373 * Isar: improved support for emulating tactic scripts, including proof
  3374 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3375 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3376 (for HOL datatypes);
  3377 
  3378 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3379 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3380 'proof method scripts' have to be in depth-first order;
  3381 
  3382 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3383 
  3384 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3385 should instead use individual commands for printing items
  3386 (print_commands, print_methods etc.);
  3387 
  3388 * Isar: added 'nothing' --- the empty list of theorems;
  3389 
  3390 
  3391 *** HOL ***
  3392 
  3393 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3394 corresponding virtual machine and a specification of its bytecode
  3395 verifier and a lightweight bytecode verifier, including proofs of
  3396 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3397 Cornelia Pusch (see also the homepage of project Bali at
  3398 http://isabelle.in.tum.de/Bali/);
  3399 
  3400 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3401 Clemens Ballarin;
  3402 
  3403 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3404 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3405 Rasmussen;
  3406 
  3407 * HOL/Lattice: fundamental concepts of lattice theory and order
  3408 structures, including duals, properties of bounds versus algebraic
  3409 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3410 Theorem for complete lattices etc.; may also serve as a demonstration
  3411 for abstract algebraic reasoning using axiomatic type classes, and
  3412 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3413 
  3414 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3415 von Oheimb;
  3416 
  3417 * HOL/IMPP: extension of IMP with local variables and mutually
  3418 recursive procedures, by David von Oheimb;
  3419 
  3420 * HOL/Lambda: converted into new-style theory and document;
  3421 
  3422 * HOL/ex/Multiquote: example of multiple nested quotations and
  3423 anti-quotations -- basically a generalized version of de-Bruijn
  3424 representation; very useful in avoiding lifting of operations;
  3425 
  3426 * HOL/record: added general record equality rule to simpset; fixed
  3427 select-update simplification procedure to handle extended records as
  3428 well; admit "r" as field name;
  3429 
  3430 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3431 other numeric types and also as the identity of groups, rings, etc.;
  3432 
  3433 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3434 Types nat and int belong to this axclass;
  3435 
  3436 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3437    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3438    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3439   two terms #m*u and #n*u are replaced by #(m+n)*u
  3440     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3441   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3442     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3443 
  3444 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3445 powerful prover for predicate logic but knows nothing of clasets; see
  3446 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3447 
  3448 * HOL: new version of "case_tac" subsumes both boolean case split and
  3449 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3450 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3451 
  3452 * HOL: simplification no longer dives into case-expressions: only the
  3453 selector expression is simplified, but not the remaining arms; to
  3454 enable full simplification of case-expressions for datatype t, you may
  3455 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3456 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3457 
  3458 * HOL/recdef: the recursion equations generated by 'recdef' for
  3459 function 'f' are now called f.simps instead of f.rules; if all
  3460 termination conditions are proved automatically, these simplification
  3461 rules are added to the simpset, as in primrec; rules may be named
  3462 individually as well, resulting in a separate list of theorems for
  3463 each equation;
  3464 
  3465 * HOL/While is a new theory that provides a while-combinator. It
  3466 permits the definition of tail-recursive functions without the
  3467 provision of a termination measure. The latter is necessary once the
  3468 invariant proof rule for while is applied.
  3469 
  3470 * HOL: new (overloaded) notation for the set of elements below/above
  3471 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3472 
  3473 * HOL: theorems impI, allI, ballI bound as "strip";
  3474 
  3475 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3476 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3477 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3478 
  3479 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3480 
  3481 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3482 main HOL, but was unused);
  3483 
  3484 * HOL: fewer consts declared as global (e.g. have to refer to
  3485 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3486 
  3487 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3488 in case of overlap with user translations (e.g. judgements over
  3489 tuples); (note that the underlying logical represenation is still
  3490 bogus);
  3491 
  3492 
  3493 *** ZF ***
  3494 
  3495 * ZF: simplification automatically cancels common terms in arithmetic
  3496 expressions over nat and int;
  3497 
  3498 * ZF: new treatment of nat to minimize type-checking: all operators
  3499 coerce their operands to a natural number using the function natify,
  3500 making the algebraic laws unconditional;
  3501 
  3502 * ZF: as above, for int: operators coerce their operands to an integer
  3503 using the function intify;
  3504 
  3505 * ZF: the integer library now contains many of the usual laws for the
  3506 orderings, including $<=, and monotonicity laws for $+ and $*;
  3507 
  3508 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3509 simplification;
  3510 
  3511 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3512 to the simplifier and classical reasoner simultaneously;
  3513 
  3514 
  3515 *** General ***
  3516 
  3517 * Provers: blast_tac now handles actual object-logic rules as
  3518 assumptions; note that auto_tac uses blast_tac internally as well;
  3519 
  3520 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3521 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3522 
  3523 * Provers: delrules now handles destruct rules as well (no longer need
  3524 explicit make_elim);
  3525 
  3526 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3527   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3528 use instead the strong form,
  3529   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3530 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3531 from destruct-rules;
  3532 
  3533 * Provers: Simplifier.easy_setup provides a fast path to basic
  3534 Simplifier setup for new object-logics;
  3535 
  3536 * Pure: AST translation rules no longer require constant head on LHS;
  3537 
  3538 * Pure: improved name spaces: ambiguous output is qualified; support
  3539 for hiding of names;
  3540 
  3541 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3542 XSYMBOL_HOME; no longer need to do manual configuration in most
  3543 situations;
  3544 
  3545 * system: compression of ML heaps images may now be controlled via -c
  3546 option of isabelle and isatool usedir (currently only observed by
  3547 Poly/ML);
  3548 
  3549 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3550 useful for remote X11);
  3551 
  3552 * system: provide TAGS file for Isabelle sources;
  3553 
  3554 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3555 order;
  3556 
  3557 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3558 timing flag supersedes proof_timing and Toplevel.trace;
  3559 
  3560 * ML: new combinators |>> and |>>> for incremental transformations
  3561 with secondary results (e.g. certain theory extensions):
  3562 
  3563 * ML: PureThy.add_defs gets additional argument to indicate potential
  3564 overloading (usually false);
  3565 
  3566 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3567 results;
  3568 
  3569 
  3570 
  3571 New in Isabelle99 (October 1999)
  3572 --------------------------------
  3573 
  3574 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3575 
  3576 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3577 are no longer simplified.  (This allows the simplifier to unfold recursive
  3578 functional programs.)  To restore the old behaviour, declare
  3579 
  3580     Delcongs [if_weak_cong];
  3581 
  3582 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3583 complement;
  3584 
  3585 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3586 
  3587 * HOL/datatype: mutual_induct_tac no longer exists --
  3588   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3589 
  3590 * HOL/typedef: fixed type inference for representing set; type
  3591 arguments now have to occur explicitly on the rhs as type constraints;
  3592 
  3593 * ZF: The con_defs part of an inductive definition may no longer refer
  3594 to constants declared in the same theory;
  3595 
  3596 * HOL, ZF: the function mk_cases, generated by the inductive
  3597 definition package, has lost an argument.  To simplify its result, it
  3598 uses the default simpset instead of a supplied list of theorems.
  3599 
  3600 * HOL/List: the constructors of type list are now Nil and Cons;
  3601 
  3602 * Simplifier: the type of the infix ML functions
  3603         setSSolver addSSolver setSolver addSolver
  3604 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3605 for packaging solvers. A solver is created via
  3606         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3607 where the string argument is only a comment.
  3608 
  3609 
  3610 *** Proof tools ***
  3611 
  3612 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3613 decision procedure for linear arithmetic. Currently it is used for
  3614 types `nat', `int', and `real' in HOL (see below); it can, should and
  3615 will be instantiated for other types and logics as well.
  3616 
  3617 * The simplifier now accepts rewrite rules with flexible heads, eg
  3618      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3619   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3620   matching.
  3621 
  3622 
  3623 *** General ***
  3624 
  3625 * New Isabelle/Isar subsystem provides an alternative to traditional
  3626 tactical theorem proving; together with the ProofGeneral/isar user
  3627 interface it offers an interactive environment for developing human
  3628 readable proof documents (Isar == Intelligible semi-automated
  3629 reasoning); for further information see isatool doc isar-ref,
  3630 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3631 
  3632 * improved and simplified presentation of theories: better HTML markup
  3633 (including colors), graph views in several sizes; isatool usedir now
  3634 provides a proper interface for user theories (via -P option); actual
  3635 document preparation based on (PDF)LaTeX is available as well (for
  3636 new-style theories only); see isatool doc system for more information;
  3637 
  3638 * native support for Proof General, both for classic Isabelle and
  3639 Isabelle/Isar;
  3640 
  3641 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3642 using the graph browser tool;
  3643 
  3644 * Isabelle manuals now also available as PDF;
  3645 
  3646 * theory loader rewritten from scratch (may not be fully
  3647 bug-compatible); old loadpath variable has been replaced by show_path,
  3648 add_path, del_path, reset_path functions; new operations such as
  3649 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3650 isatool doc ref);
  3651 
  3652 * improved isatool install: option -k creates KDE application icon,
  3653 option -p DIR installs standalone binaries;
  3654 
  3655 * added ML_PLATFORM setting (useful for cross-platform installations);
  3656 more robust handling of platform specific ML images for SML/NJ;
  3657 
  3658 * the settings environment is now statically scoped, i.e. it is never
  3659 created again in sub-processes invoked from isabelle, isatool, or
  3660 Isabelle;
  3661 
  3662 * path element specification '~~' refers to '$ISABELLE_HOME';
  3663 
  3664 * in locales, the "assumes" and "defines" parts may be omitted if
  3665 empty;
  3666 
  3667 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3668 long arrows);
  3669 
  3670 * new print_mode "HTML";
  3671 
  3672 * new flag show_tags controls display of tags of theorems (which are
  3673 basically just comments that may be attached by some tools);
  3674 
  3675 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3676 mode and goal output format:
  3677 
  3678 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3679 244c244
  3680 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3681 ---
  3682 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3683 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3684 181c181
  3685 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3686 ---
  3687 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3688 
  3689 * function bind_thms stores lists of theorems (cf. bind_thm);
  3690 
  3691 * new shorthand tactics ftac, eatac, datac, fatac;
  3692 
  3693 * qed (and friends) now accept "" as result name; in that case the
  3694 theorem is not stored, but proper checks and presentation of the
  3695 result still apply;
  3696 
  3697 * theorem database now also indexes constants "Trueprop", "all",
  3698 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3699 
  3700 
  3701 *** HOL ***
  3702 
  3703 ** HOL arithmetic **
  3704 
  3705 * There are now decision procedures for linear arithmetic over nat and
  3706 int:
  3707 
  3708 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3709 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3710 are treated as atomic; subformulae not involving type `nat' or `int'
  3711 are ignored; quantified subformulae are ignored unless they are
  3712 positive universal or negative existential. The tactic has to be
  3713 invoked by hand and can be a little bit slow. In particular, the
  3714 running time is exponential in the number of occurrences of `min' and
  3715 `max', and `-' on `nat'.
  3716 
  3717 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3718 (negated) (in)equalities among the premises and the conclusion into
  3719 account (i.e. no compound formulae) and does not know about `min' and
  3720 `max', and `-' on `nat'. It is fast and is used automatically by the
  3721 simplifier.
  3722 
  3723 NB: At the moment, these decision procedures do not cope with mixed
  3724 nat/int formulae where the two parts interact, such as `m < n ==>
  3725 int(m) < int(n)'.
  3726 
  3727 * HOL/Numeral provides a generic theory of numerals (encoded
  3728 efficiently as bit strings); setup for types nat/int/real is in place;
  3729 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3730 int, existing theories and proof scripts may require a few additional
  3731 type constraints;
  3732 
  3733 * integer division and remainder can now be performed on constant
  3734 arguments;
  3735 
  3736 * many properties of integer multiplication, division and remainder
  3737 are now available;
  3738 
  3739 * An interface to the Stanford Validity Checker (SVC) is available through the
  3740 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3741 are proved automatically.  SVC must be installed separately, and its results
  3742 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3743 invocation of the underlying oracle).  For SVC see
  3744   http://verify.stanford.edu/SVC
  3745 
  3746 * IsaMakefile: the HOL-Real target now builds an actual image;
  3747 
  3748 
  3749 ** HOL misc **
  3750 
  3751 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3752 (in Isabelle/Isar) -- by Gertrud Bauer;
  3753 
  3754 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3755 analysis for assembly languages with subtypes;
  3756 
  3757 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3758 -- avoids syntactic ambiguities and treats state, transition, and
  3759 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3760 changed syntax and (many) tactics;
  3761 
  3762 * HOL/inductive: Now also handles more general introduction rules such
  3763   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3764   theorems are now maintained within the theory (maintained via the
  3765   "mono" attribute);
  3766 
  3767 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3768   (using function types) such as
  3769 
  3770   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3771 
  3772 * HOL/record: record_simproc (part of the default simpset) takes care
  3773 of selectors applied to updated records; record_split_tac is no longer
  3774 part of the default claset; update_defs may now be removed from the
  3775 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3776 
  3777   claset_ref () := claset() addSWrapper record_split_wrapper;
  3778   Delsimprocs [record_simproc]
  3779 
  3780 * HOL/typedef: fixed type inference for representing set; type
  3781 arguments now have to occur explicitly on the rhs as type constraints;
  3782 
  3783 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3784 names rather than an ML expression;
  3785 
  3786 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3787 supplied later.  Program schemes can be defined, such as
  3788     "While B C s = (if B s then While B C (C s) else s)"
  3789 where the well-founded relation can be chosen after B and C have been given.
  3790 
  3791 * HOL/List: the constructors of type list are now Nil and Cons;
  3792 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3793 course, ML tools referring to List.list.op # etc. have to be adapted;
  3794 
  3795 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3796 disabled by default; run isabelle with option -m HOL to get back to
  3797 the original Gordon/HOL-style output;
  3798 
  3799 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3800 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3801 
  3802 * HOL basic syntax simplified (more orthogonal): all variants of
  3803 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3804 Eps operator is provided as well: "SOME x. P[x]";
  3805 
  3806 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3807 
  3808 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3809 thus available for user theories;
  3810 
  3811 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3812 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3813 time;
  3814 
  3815 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3816 several times and then mp;
  3817 
  3818 
  3819 *** LK ***
  3820 
  3821 * the notation <<...>> is now available as a notation for sequences of
  3822 formulas;
  3823 
  3824 * the simplifier is now installed
  3825 
  3826 * the axiom system has been generalized (thanks to Soren Heilmann)
  3827 
  3828 * the classical reasoner now has a default rule database
  3829 
  3830 
  3831 *** ZF ***
  3832 
  3833 * new primrec section allows primitive recursive functions to be given
  3834 directly (as in HOL) over datatypes and the natural numbers;
  3835 
  3836 * new tactics induct_tac and exhaust_tac for induction (or case
  3837 analysis) over datatypes and the natural numbers;
  3838 
  3839 * the datatype declaration of type T now defines the recursor T_rec;
  3840 
  3841 * simplification automatically does freeness reasoning for datatype
  3842 constructors;
  3843 
  3844 * automatic type-inference, with AddTCs command to insert new
  3845 type-checking rules;
  3846 
  3847 * datatype introduction rules are now added as Safe Introduction rules
  3848 to the claset;
  3849 
  3850 * the syntax "if P then x else y" is now available in addition to
  3851 if(P,x,y);
  3852 
  3853 
  3854 *** Internal programming interfaces ***
  3855 
  3856 * tuned simplifier trace output; new flag debug_simp;
  3857 
  3858 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3859 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3860 
  3861 * AxClass.axclass_tac lost the theory argument;
  3862 
  3863 * tuned current_goals_markers semantics: begin / end goal avoids
  3864 printing empty lines;
  3865 
  3866 * removed prs and prs_fn hook, which was broken because it did not
  3867 include \n in its semantics, forcing writeln to add one
  3868 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3869 string -> unit if you really want to output text without newline;
  3870 
  3871 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3872 plain output, interface builders may have to enable 'isabelle_font'
  3873 mode to get Isabelle font glyphs as before;
  3874 
  3875 * refined token_translation interface; INCOMPATIBILITY: output length
  3876 now of type real instead of int;
  3877 
  3878 * theory loader actions may be traced via new ThyInfo.add_hook
  3879 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3880 your own database of information attached to *whole* theories -- as
  3881 opposed to intra-theory data slots offered via TheoryDataFun;
  3882 
  3883 * proper handling of dangling sort hypotheses (at last!);
  3884 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3885 extra sort hypotheses that can be witnessed from the type signature;
  3886 the force_strip_shyps flag is gone, any remaining shyps are simply
  3887 left in the theorem (with a warning issued by strip_shyps_warning);
  3888 
  3889 
  3890 
  3891 New in Isabelle98-1 (October 1998)
  3892 ----------------------------------
  3893 
  3894 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3895 
  3896 * several changes of automated proof tools;
  3897 
  3898 * HOL: major changes to the inductive and datatype packages, including
  3899 some minor incompatibilities of theory syntax;
  3900 
  3901 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3902 called `inj_on';
  3903 
  3904 * HOL: removed duplicate thms in Arith:
  3905   less_imp_add_less  should be replaced by  trans_less_add1
  3906   le_imp_add_le      should be replaced by  trans_le_add1
  3907 
  3908 * HOL: unary minus is now overloaded (new type constraints may be
  3909 required);
  3910 
  3911 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3912 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3913 now taken as an integer constant.
  3914 
  3915 * Pure: ML function 'theory_of' renamed to 'theory';
  3916 
  3917 
  3918 *** Proof tools ***
  3919 
  3920 * Simplifier:
  3921   1. Asm_full_simp_tac is now more aggressive.
  3922      1. It will sometimes reorient premises if that increases their power to
  3923         simplify.
  3924      2. It does no longer proceed strictly from left to right but may also
  3925         rotate premises to achieve further simplification.
  3926      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3927      old Asm_full_simp_tac in that it does not rotate premises.
  3928   2. The simplifier now knows a little bit about nat-arithmetic.
  3929 
  3930 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3931 allows for selected deletion of wrappers, by introduction of names for
  3932 wrapper functionals.  This implies that addbefore, addSbefore,
  3933 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3934 and that adding two tactics with the same name overwrites the first
  3935 one (emitting a warning).
  3936   type wrapper = (int -> tactic) -> (int -> tactic)
  3937   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3938   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3939   delWrapper, delSWrapper: claset *  string            -> claset
  3940   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3941 
  3942 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3943 semantics; addbefore now affects only the unsafe part of step_tac
  3944 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3945 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3946 by Force_tac;
  3947 
  3948 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3949 compWrapper; added safe wrapper (and access functions for it);
  3950 
  3951 * HOL/split_all_tac is now much faster and fails if there is nothing
  3952 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3953 and the names of the automatically generated variables have changed.
  3954 split_all_tac has moved within claset() from unsafe wrappers to safe
  3955 wrappers, which means that !!-bound variables are split much more
  3956 aggressively, and safe_tac and clarify_tac now split such variables.
  3957 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3958 Note: the same holds for record_split_tac, which does the job of
  3959 split_all_tac for record fields.
  3960 
  3961 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3962 permanently to the default simpset using Addsplits just like
  3963 Addsimps. They can be removed via Delsplits just like
  3964 Delsimps. Lower-case versions are also available.
  3965 
  3966 * HOL/Simplifier: The rule split_if is now part of the default
  3967 simpset. This means that the simplifier will eliminate all occurrences
  3968 of if-then-else in the conclusion of a goal. To prevent this, you can
  3969 either remove split_if completely from the default simpset by
  3970 `Delsplits [split_if]' or remove it in a specific call of the
  3971 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3972 other case splitting rules to/from the default simpset: every datatype
  3973 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3974 t is the name of the datatype).
  3975 
  3976 * Classical reasoner / Simplifier combination: new force_tac (and
  3977 derivatives Force_tac, force) combines rewriting and classical
  3978 reasoning (and whatever other tools) similarly to auto_tac, but is
  3979 aimed to solve the given subgoal completely.
  3980 
  3981 
  3982 *** General ***
  3983 
  3984 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3985 and `goalw': the theory is no longer needed as an explicit argument -
  3986 the current theory context is used; assumptions are no longer returned
  3987 at the ML-level unless one of them starts with ==> or !!; it is
  3988 recommended to convert to these new commands using isatool fixgoal
  3989 (backup your sources first!);
  3990 
  3991 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3992 the current theory context, and 'theory' to lookup stored theories;
  3993 
  3994 * new theory section 'locale' for declaring constants, assumptions and
  3995 definitions that have local scope;
  3996 
  3997 * new theory section 'nonterminals' for purely syntactic types;
  3998 
  3999 * new theory section 'setup' for generic ML setup functions
  4000 (e.g. package initialization);
  4001 
  4002 * the distribution now includes Isabelle icons: see
  4003 lib/logo/isabelle-{small,tiny}.xpm;
  4004 
  4005 * isatool install - install binaries with absolute references to
  4006 ISABELLE_HOME/bin;
  4007 
  4008 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4009 
  4010 * print mode 'emacs' reserved for Isamode;
  4011 
  4012 * support multiple print (ast) translations per constant name;
  4013 
  4014 * theorems involving oracles are now printed with a suffixed [!];
  4015 
  4016 
  4017 *** HOL ***
  4018 
  4019 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4020 
  4021 * HOL/inductive package reorganized and improved: now supports mutual
  4022 definitions such as
  4023 
  4024   inductive EVEN ODD
  4025     intrs
  4026       null "0 : EVEN"
  4027       oddI "n : EVEN ==> Suc n : ODD"
  4028       evenI "n : ODD ==> Suc n : EVEN"
  4029 
  4030 new theorem list "elims" contains an elimination rule for each of the
  4031 recursive sets; inductive definitions now handle disjunctive premises
  4032 correctly (also ZF);
  4033 
  4034 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4035 "mutual_induct" no longer exists - the induction rule is always
  4036 contained in "induct";
  4037 
  4038 
  4039 * HOL/datatype package re-implemented and greatly improved: now
  4040 supports mutually recursive datatypes such as
  4041 
  4042   datatype
  4043     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4044             | SUM ('a aexp) ('a aexp)
  4045             | DIFF ('a aexp) ('a aexp)
  4046             | NUM 'a
  4047   and
  4048     'a bexp = LESS ('a aexp) ('a aexp)
  4049             | AND ('a bexp) ('a bexp)
  4050             | OR ('a bexp) ('a bexp)
  4051 
  4052 as well as indirectly recursive datatypes such as
  4053 
  4054   datatype
  4055     ('a, 'b) term = Var 'a
  4056                   | App 'b ((('a, 'b) term) list)
  4057 
  4058 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4059 induction on mutually / indirectly recursive datatypes.
  4060 
  4061 Primrec equations are now stored in theory and can be accessed via
  4062 <function_name>.simps.
  4063 
  4064 INCOMPATIBILITIES:
  4065 
  4066   - Theories using datatypes must now have theory Datatype as an
  4067     ancestor.
  4068   - The specific <typename>.induct_tac no longer exists - use the
  4069     generic induct_tac instead.
  4070   - natE has been renamed to nat.exhaust - use exhaust_tac
  4071     instead of res_inst_tac ... natE. Note that the variable
  4072     names in nat.exhaust differ from the names in natE, this
  4073     may cause some "fragile" proofs to fail.
  4074   - The theorems split_<typename>_case and split_<typename>_case_asm
  4075     have been renamed to <typename>.split and <typename>.split_asm.
  4076   - Since default sorts of type variables are now handled correctly,
  4077     some datatype definitions may have to be annotated with explicit
  4078     sort constraints.
  4079   - Primrec definitions no longer require function name and type
  4080     of recursive argument.
  4081 
  4082 Consider using isatool fixdatatype to adapt your theories and proof
  4083 scripts to the new package (backup your sources first!).
  4084 
  4085 
  4086 * HOL/record package: considerably improved implementation; now
  4087 includes concrete syntax for record types, terms, updates; theorems
  4088 for surjective pairing and splitting !!-bound record variables; proof
  4089 support is as follows:
  4090 
  4091   1) standard conversions (selectors or updates applied to record
  4092 constructor terms) are part of the standard simpset;
  4093 
  4094   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4095 made part of standard simpset and claset via addIffs;
  4096 
  4097   3) a tactic for record field splitting (record_split_tac) is part of
  4098 the standard claset (addSWrapper);
  4099 
  4100 To get a better idea about these rules you may retrieve them via
  4101 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4102 the name of your record type.
  4103 
  4104 The split tactic 3) conceptually simplifies by the following rule:
  4105 
  4106   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4107 
  4108 Thus any record variable that is bound by meta-all will automatically
  4109 blow up into some record constructor term, consequently the
  4110 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4111 solve record problems automatically.
  4112 
  4113 
  4114 * reorganized the main HOL image: HOL/Integ and String loaded by
  4115 default; theory Main includes everything;
  4116 
  4117 * automatic simplification of integer sums and comparisons, using cancellation;
  4118 
  4119 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4120 
  4121 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4122 
  4123 * many new identities for unions, intersections, set difference, etc.;
  4124 
  4125 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4126 called split_if, split_split, split_sum_case and split_nat_case (to go
  4127 with add/delsplits);
  4128 
  4129 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4130 (?x::unit) = (); this is made part of the default simpset, which COULD
  4131 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4132 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4133 unit_abs_eta_conv is added in order to counter the effect of
  4134 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4135 %u.f();
  4136 
  4137 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4138 makes more sense);
  4139 
  4140 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4141   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4142   disjointness reasoning but breaking a few old proofs.
  4143 
  4144 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4145 to 'converse' from 'inverse' (for compatibility with ZF and some
  4146 literature);
  4147 
  4148 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4149 the well-founded relation;
  4150 
  4151 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4152     Compl A.  The "Compl" syntax remains available as input syntax for this
  4153     release ONLY.
  4154 
  4155 * HOL/Update: new theory of function updates:
  4156     f(a:=b) == %x. if x=a then b else f x
  4157 may also be iterated as in f(a:=b,c:=d,...);
  4158 
  4159 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4160 
  4161 * HOL/List:
  4162   - new function list_update written xs[i:=v] that updates the i-th
  4163     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4164   - new function `upt' written [i..j(] which generates the list
  4165     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4166     bound write [i..j], which is a shorthand for [i..j+1(].
  4167   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4168 
  4169 * HOL/Arith:
  4170   - removed 'pred' (predecessor) function;
  4171   - generalized some theorems about n-1;
  4172   - many new laws about "div" and "mod";
  4173   - new laws about greatest common divisors (see theory ex/Primes);
  4174 
  4175 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4176 instead of "inverse";
  4177 
  4178 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4179   of the multiset ordering;
  4180 
  4181 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4182   (not included by default);
  4183 
  4184 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4185 
  4186 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4187   programs, i.e. different program variables may have different types.
  4188 
  4189 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4190   [previously, this check worked only if the rewrite rule was unconditional]
  4191   Now rew can involve either definitions or equalities (either == or =).
  4192 
  4193 
  4194 *** ZF ***
  4195 
  4196 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4197   only the theorems proved on ZF.ML;
  4198 
  4199 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4200   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4201   disjointness reasoning but breaking a few old proofs.
  4202 
  4203 * ZF/Update: new theory of function updates
  4204     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4205   may also be iterated as in f(a:=b,c:=d,...);
  4206 
  4207 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4208 
  4209 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4210   [previously, this check worked only if the rewrite rule was unconditional]
  4211   Now rew can involve either definitions or equalities (either == or =).
  4212 
  4213 * case_tac provided for compatibility with HOL
  4214     (like the old excluded_middle_tac, but with subgoals swapped)
  4215 
  4216 
  4217 *** Internal programming interfaces ***
  4218 
  4219 * Pure: several new basic modules made available for general use, see
  4220 also src/Pure/README;
  4221 
  4222 * improved the theory data mechanism to support encapsulation (data
  4223 kind name replaced by private Object.kind, acting as authorization
  4224 key); new type-safe user interface via functor TheoryDataFun; generic
  4225 print_data function becomes basically useless;
  4226 
  4227 * removed global_names compatibility flag -- all theory declarations
  4228 are qualified by default;
  4229 
  4230 * module Pure/Syntax now offers quote / antiquote translation
  4231 functions (useful for Hoare logic etc. with implicit dependencies);
  4232 see HOL/ex/Antiquote for an example use;
  4233 
  4234 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4235 cterm -> thm;
  4236 
  4237 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4238 subgoal;
  4239 
  4240 * Display.print_goals function moved to Locale.print_goals;
  4241 
  4242 * standard print function for goals supports current_goals_markers
  4243 variable for marking begin of proof, end of proof, start of goal; the
  4244 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4245 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4246 for example;
  4247 
  4248 
  4249 
  4250 New in Isabelle98 (January 1998)
  4251 --------------------------------
  4252 
  4253 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4254 
  4255 * changed lexical syntax of terms / types: dots made part of long
  4256 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4257 
  4258 * simpset (and claset) reference variable replaced by functions
  4259 simpset / simpset_ref;
  4260 
  4261 * no longer supports theory aliases (via merge) and non-trivial
  4262 implicit merge of thms' signatures;
  4263 
  4264 * most internal names of constants changed due to qualified names;
  4265 
  4266 * changed Pure/Sequence interface (see Pure/seq.ML);
  4267 
  4268 
  4269 *** General Changes ***
  4270 
  4271 * hierachically structured name spaces (for consts, types, axms, thms
  4272 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4273 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4274 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4275 long_names for fully qualified output names; NOTE: ML programs
  4276 (special tactics, packages etc.) referring to internal names may have
  4277 to be adapted to cope with fully qualified names; in case of severe
  4278 backward campatibility problems try setting 'global_names' at compile
  4279 time to have enrything declared within a flat name space; one may also
  4280 fine tune name declarations in theories via the 'global' and 'local'
  4281 section;
  4282 
  4283 * reimplemented the implicit simpset and claset using the new anytype
  4284 data filed in signatures; references simpset:simpset ref etc. are
  4285 replaced by functions simpset:unit->simpset and
  4286 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4287 to patch your ML files accordingly;
  4288 
  4289 * HTML output now includes theory graph data for display with Java
  4290 applet or isatool browser; data generated automatically via isatool
  4291 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4292 
  4293 * defs may now be conditional; improved rewrite_goals_tac to handle
  4294 conditional equations;
  4295 
  4296 * defs now admits additional type arguments, using TYPE('a) syntax;
  4297 
  4298 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4299 creates a new theory node; implicit merge of thms' signatures is
  4300 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4301 transfer:theory->thm->thm in (rare) cases;
  4302 
  4303 * improved handling of draft signatures / theories; draft thms (and
  4304 ctyps, cterms) are automatically promoted to real ones;
  4305 
  4306 * slightly changed interfaces for oracles: admit many per theory, named
  4307 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4308 
  4309 * print_goals: optional output of const types (set show_consts and
  4310 show_types);
  4311 
  4312 * improved output of warnings (###) and errors (***);
  4313 
  4314 * subgoal_tac displays a warning if the new subgoal has type variables;
  4315 
  4316 * removed old README and Makefiles;
  4317 
  4318 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4319 
  4320 * removed obsolete init_pps and init_database;
  4321 
  4322 * deleted the obsolete tactical STATE, which was declared by
  4323     fun STATE tacfun st = tacfun st st;
  4324 
  4325 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4326 (which abbreviates $HOME);
  4327 
  4328 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4329 use isatool fixseq to adapt your ML programs (this works for fully
  4330 qualified references to the Sequence structure only!);
  4331 
  4332 * use_thy no longer requires writable current directory; it always
  4333 reloads .ML *and* .thy file, if either one is out of date;
  4334 
  4335 
  4336 *** Classical Reasoner ***
  4337 
  4338 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4339 tactics that use classical reasoning to simplify a subgoal without
  4340 splitting it into several subgoals;
  4341 
  4342 * Safe_tac: like safe_tac but uses the default claset;
  4343 
  4344 
  4345 *** Simplifier ***
  4346 
  4347 * added simplification meta rules:
  4348     (asm_)(full_)simplify: simpset -> thm -> thm;
  4349 
  4350 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4351 logics (again);
  4352 
  4353 * added prems argument to simplification procedures;
  4354 
  4355 * HOL, FOL, ZF: added infix function `addsplits':
  4356   instead of `<simpset> setloop (split_tac <thms>)'
  4357   you can simply write `<simpset> addsplits <thms>'
  4358 
  4359 
  4360 *** Syntax ***
  4361 
  4362 * TYPE('a) syntax for type reflection terms;
  4363 
  4364 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4365 
  4366 * pretty printer: changed order of mixfix annotation preference (again!);
  4367 
  4368 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4369 
  4370 
  4371 *** HOL ***
  4372 
  4373 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4374   with `addloop' of the simplifier to faciliate case splitting in premises.
  4375 
  4376 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4377 
  4378 * HOL/Auth: new protocol proofs including some for the Internet
  4379   protocol TLS;
  4380 
  4381 * HOL/Map: new theory of `maps' a la VDM;
  4382 
  4383 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4384 cancelling out common nat summands from =, <, <= (in)equalities, or
  4385 differences; simplification procedures nat_cancel_factor for
  4386 cancelling common factor from =, <, <= (in)equalities over natural
  4387 sums; nat_cancel contains both kinds of procedures, it is installed by
  4388 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4389 
  4390 * HOL/simplifier: terms of the form
  4391   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4392   are rewritten to
  4393   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4394   and those of the form
  4395   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4396   are rewritten to
  4397   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4398 
  4399 * HOL/datatype
  4400   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4401 
  4402   P(t_case f1 ... fn x) =
  4403      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4404         ...
  4405        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4406      )
  4407 
  4408   and a theorem `split_t_case_asm' of the form
  4409 
  4410   P(t_case f1 ... fn x) =
  4411     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4412         ...
  4413        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4414      )
  4415   which can be added to a simpset via `addsplits'. The existing theorems
  4416   expand_list_case and expand_option_case have been renamed to
  4417   split_list_case and split_option_case.
  4418 
  4419 * HOL/Arithmetic:
  4420   - `pred n' is automatically converted to `n-1'.
  4421     Users are strongly encouraged not to use `pred' any longer,
  4422     because it will disappear altogether at some point.
  4423   - Users are strongly encouraged to write "0 < n" rather than
  4424     "n ~= 0". Theorems and proof tools have been modified towards this
  4425     `standard'.
  4426 
  4427 * HOL/Lists:
  4428   the function "set_of_list" has been renamed "set" (and its theorems too);
  4429   the function "nth" now takes its arguments in the reverse order and
  4430   has acquired the infix notation "!" as in "xs!n".
  4431 
  4432 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4433 
  4434 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4435   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4436 
  4437 * HOL/record: extensible records with schematic structural subtyping
  4438 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4439 still lacks various theorems and concrete record syntax;
  4440 
  4441 
  4442 *** HOLCF ***
  4443 
  4444 * removed "axioms" and "generated by" sections;
  4445 
  4446 * replaced "ops" section by extended "consts" section, which is capable of
  4447   handling the continuous function space "->" directly;
  4448 
  4449 * domain package:
  4450   . proves theorems immediately and stores them in the theory,
  4451   . creates hierachical name space,
  4452   . now uses normal mixfix annotations (instead of cinfix...),
  4453   . minor changes to some names and values (for consistency),
  4454   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4455   . separator between mutual domain defs: changed "," to "and",
  4456   . improved handling of sort constraints;  now they have to
  4457     appear on the left-hand side of the equations only;
  4458 
  4459 * fixed LAM <x,y,zs>.b syntax;
  4460 
  4461 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4462 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4463 
  4464 
  4465 *** FOL and ZF ***
  4466 
  4467 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4468   with `addloop' of the simplifier to faciliate case splitting in premises.
  4469 
  4470 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4471 in HOL, they strip ALL and --> from proved theorems;
  4472 
  4473 
  4474 
  4475 New in Isabelle94-8 (May 1997)
  4476 ------------------------------
  4477 
  4478 *** General Changes ***
  4479 
  4480 * new utilities to build / run / maintain Isabelle etc. (in parts
  4481 still somewhat experimental); old Makefiles etc. still functional;
  4482 
  4483 * new 'Isabelle System Manual';
  4484 
  4485 * INSTALL text, together with ./configure and ./build scripts;
  4486 
  4487 * reimplemented type inference for greater efficiency, better error
  4488 messages and clean internal interface;
  4489 
  4490 * prlim command for dealing with lots of subgoals (an easier way of
  4491 setting goals_limit);
  4492 
  4493 
  4494 *** Syntax ***
  4495 
  4496 * supports alternative (named) syntax tables (parser and pretty
  4497 printer); internal interface is provided by add_modesyntax(_i);
  4498 
  4499 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4500 be used in conjunction with the Isabelle symbol font; uses the
  4501 "symbols" syntax table;
  4502 
  4503 * added token_translation interface (may translate name tokens in
  4504 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4505 the current print_mode); IMPORTANT: user print translation functions
  4506 are responsible for marking newly introduced bounds
  4507 (Syntax.mark_boundT);
  4508 
  4509 * token translations for modes "xterm" and "xterm_color" that display
  4510 names in bold, underline etc. or colors (which requires a color
  4511 version of xterm);
  4512 
  4513 * infixes may now be declared with names independent of their syntax;
  4514 
  4515 * added typed_print_translation (like print_translation, but may
  4516 access type of constant);
  4517 
  4518 
  4519 *** Classical Reasoner ***
  4520 
  4521 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4522 some limitations.  Blast_tac...
  4523   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4524   + ignores elimination rules that don't have the correct format
  4525         (the conclusion MUST be a formula variable)
  4526   + ignores types, which can make HOL proofs fail
  4527   + rules must not require higher-order unification, e.g. apply_type in ZF
  4528     [message "Function Var's argument not a bound variable" relates to this]
  4529   + its proof strategy is more general but can actually be slower
  4530 
  4531 * substitution with equality assumptions no longer permutes other
  4532 assumptions;
  4533 
  4534 * minor changes in semantics of addafter (now called addaltern); renamed
  4535 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4536 (and access functions for it);
  4537 
  4538 * improved combination of classical reasoner and simplifier:
  4539   + functions for handling clasimpsets
  4540   + improvement of addss: now the simplifier is called _after_ the
  4541     safe steps.
  4542   + safe variant of addss called addSss: uses safe simplifications
  4543     _during_ the safe steps. It is more complete as it allows multiple
  4544     instantiations of unknowns (e.g. with slow_tac).
  4545 
  4546 *** Simplifier ***
  4547 
  4548 * added interface for simplification procedures (functions that
  4549 produce *proven* rewrite rules on the fly, depending on current
  4550 redex);
  4551 
  4552 * ordering on terms as parameter (used for ordered rewriting);
  4553 
  4554 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4555 
  4556 * the solver is now split into a safe and an unsafe part.
  4557 This should be invisible for the normal user, except that the
  4558 functions setsolver and addsolver have been renamed to setSolver and
  4559 addSolver; added safe_asm_full_simp_tac;
  4560 
  4561 
  4562 *** HOL ***
  4563 
  4564 * a generic induction tactic `induct_tac' which works for all datatypes and
  4565 also for type `nat';
  4566 
  4567 * a generic case distinction tactic `exhaust_tac' which works for all
  4568 datatypes and also for type `nat';
  4569 
  4570 * each datatype comes with a function `size';
  4571 
  4572 * patterns in case expressions allow tuple patterns as arguments to
  4573 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4574 
  4575 * primrec now also works with type nat;
  4576 
  4577 * recdef: a new declaration form, allows general recursive functions to be
  4578 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4579 
  4580 * the constant for negation has been renamed from "not" to "Not" to
  4581 harmonize with FOL, ZF, LK, etc.;
  4582 
  4583 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4584 infinite lists;
  4585 
  4586 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4587 
  4588 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4589 problems in commutative rings, using axiomatic type classes for + and *;
  4590 
  4591 * more examples in HOL/MiniML and HOL/Auth;
  4592 
  4593 * more default rewrite rules for quantifiers, union/intersection;
  4594 
  4595 * a new constant `arbitrary == @x.False';
  4596 
  4597 * HOLCF/IOA replaces old HOL/IOA;
  4598 
  4599 * HOLCF changes: derived all rules and arities
  4600   + axiomatic type classes instead of classes
  4601   + typedef instead of faking type definitions
  4602   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4603   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4604   + eliminated the types void, one, tr
  4605   + use unit lift and bool lift (with translations) instead of one and tr
  4606   + eliminated blift from Lift3.thy (use Def instead of blift)
  4607   all eliminated rules are derived as theorems --> no visible changes ;
  4608 
  4609 
  4610 *** ZF ***
  4611 
  4612 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4613 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4614 as ZF_cs addSIs [equalityI];
  4615 
  4616 
  4617 
  4618 New in Isabelle94-7 (November 96)
  4619 ---------------------------------
  4620 
  4621 * allowing negative levels (as offsets) in prlev and choplev;
  4622 
  4623 * super-linear speedup for large simplifications;
  4624 
  4625 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4626 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4627 FAIL); can suppress it using the command Delsimps (ex_simps @
  4628 all_simps); De Morgan laws are also now included, by default;
  4629 
  4630 * improved printing of ==>  :  ~:
  4631 
  4632 * new object-logic "Sequents" adds linear logic, while replacing LK
  4633 and Modal (thanks to Sara Kalvala);
  4634 
  4635 * HOL/Auth: correctness proofs for authentication protocols;
  4636 
  4637 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4638 examples on HOL/Auth);
  4639 
  4640 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4641 the rewriter and classical reasoner simultaneously;
  4642 
  4643 * function uresult no longer returns theorems in "standard" format;
  4644 regain previous version by: val uresult = standard o uresult;
  4645 
  4646 
  4647 
  4648 New in Isabelle94-6
  4649 -------------------
  4650 
  4651 * oracles -- these establish an interface between Isabelle and trusted
  4652 external reasoners, which may deliver results as theorems;
  4653 
  4654 * proof objects (in particular record all uses of oracles);
  4655 
  4656 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4657 
  4658 * "constdefs" section in theory files;
  4659 
  4660 * "primrec" section (HOL) no longer requires names;
  4661 
  4662 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4663 
  4664 
  4665 
  4666 New in Isabelle94-5
  4667 -------------------
  4668 
  4669 * reduced space requirements;
  4670 
  4671 * automatic HTML generation from theories;
  4672 
  4673 * theory files no longer require "..." (quotes) around most types;
  4674 
  4675 * new examples, including two proofs of the Church-Rosser theorem;
  4676 
  4677 * non-curried (1994) version of HOL is no longer distributed;
  4678 
  4679 
  4680 
  4681 New in Isabelle94-4
  4682 -------------------
  4683 
  4684 * greatly reduced space requirements;
  4685 
  4686 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4687 
  4688 * searchable theorem database (see the section "Retrieving theorems" on
  4689 page 8 of the Reference Manual);
  4690 
  4691 * new examples, including Grabczewski's monumental case study of the
  4692 Axiom of Choice;
  4693 
  4694 * The previous version of HOL renamed to Old_HOL;
  4695 
  4696 * The new version of HOL (previously called CHOL) uses a curried syntax
  4697 for functions.  Application looks like f a b instead of f(a,b);
  4698 
  4699 * Mutually recursive inductive definitions finally work in HOL;
  4700 
  4701 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4702 translates to the operator "split";
  4703 
  4704 
  4705 
  4706 New in Isabelle94-3
  4707 -------------------
  4708 
  4709 * new infix operator, addss, allowing the classical reasoner to
  4710 perform simplification at each step of its search.  Example:
  4711         fast_tac (cs addss ss)
  4712 
  4713 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4714 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4715 look like (a,b) instead of <a,b>;
  4716 
  4717 * PLEASE NOTE: CHOL will eventually replace HOL!
  4718 
  4719 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4720 It translates to the operator "split".  A new theory of integers is available;
  4721 
  4722 * In ZF, integer numerals now denote two's-complement binary integers.
  4723 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4724 
  4725 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4726 of the Axiom of Choice;
  4727 
  4728 
  4729 
  4730 New in Isabelle94-2
  4731 -------------------
  4732 
  4733 * Significantly faster resolution;
  4734 
  4735 * the different sections in a .thy file can now be mixed and repeated
  4736 freely;
  4737 
  4738 * Database of theorems for FOL, HOL and ZF.  New
  4739 commands including qed, qed_goal and bind_thm store theorems in the database.
  4740 
  4741 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4742 a given theory (thms_of), or find out what theory a theorem was proved in
  4743 (theory_of_thm);
  4744 
  4745 * Bugs fixed in the inductive definition and datatype packages;
  4746 
  4747 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4748 and HOL_dup_cs obsolete;
  4749 
  4750 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4751 have been removed;
  4752 
  4753 * Simpler definition of function space in ZF;
  4754 
  4755 * new results about cardinal and ordinal arithmetic in ZF;
  4756 
  4757 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4758 types;
  4759 
  4760 
  4761 $Id$