NEWS
author nipkow
Sat May 19 07:47:51 2007 +0200 (2007-05-19)
changeset 23013 c38c9039dc13
parent 22997 d4f3b015b50b
child 23029 79ee75dc1e59
permissions -rw-r--r--
*** empty log message ***
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * More uniform information about legacy features, notably a
    10 warning/error of "Legacy feature: ...", depending on the state of the
    11 tolerate_legacy_features flag (default true).
    12 
    13 * Theory syntax: the header format ``theory A = B + C:'' has been
    14 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    15 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    16 
    17 * Theory syntax: the old non-Isar theory file format has been
    18 discontinued altogether.  Note that ML proof scripts may still be used
    19 with Isar theories; migration is usually quite simple with the ML
    20 function use_legacy_bindings.  INCOMPATIBILITY.
    21 
    22 * Theory syntax: some popular names (e.g. 'class', 'declaration',
    23 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
    24 quotes.
    25 
    26 * Legacy goal package: reduced interface to the bare minimum required
    27 to keep existing proof scripts running.  Most other user-level
    28 functions are now part of the OldGoals structure, which is *not* open
    29 by default (consider isatool expandshort before open OldGoals).
    30 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    31 these tend to cause confusion about the actual goal (!) context being
    32 used here, which is not necessarily the same as the_context().
    33 
    34 * Command 'find_theorems': support "*" wildcard in "name:" criterion.
    35 
    36 * Proof General interface: A search form for the "Find Theorems" command is
    37 now available via C-c C-a C-f.  The old minibuffer interface is available
    38 via C-c C-a C-m.  Variable proof-find-theorems-command (customizable via
    39 'Proof-General -> Advanced -> Internals -> Prover Config') controls the
    40 default behavior of 'ProofGeneral -> Find Theorems' (C-c C-f): set to
    41 isar-find-theorems-form or isar-find-theorems-minibuffer.
    42 
    43 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    44 by default, which means that "prems" (and also "fixed variables") are
    45 suppressed from proof state output.  Note that the ProofGeneral
    46 settings mechanism allows to change and save options persistently, but
    47 older versions of Isabelle will fail to start up if a negative prems
    48 limit is imposed.
    49 
    50 * Local theory targets may be specified by non-nested blocks of
    51 ``context/locale/class ... begin'' followed by ``end''.  The body may
    52 contain definitions, theorems etc., including any derived mechanism
    53 that has been implemented on top of these primitives.  This concept
    54 generalizes the existing ``theorem (in ...)'' towards more versatility
    55 and scalability.
    56 
    57 * Proof General interface: proper undo of final 'end' command;
    58 discontinued Isabelle/classic mode (ML proof scripts).
    59 
    60 
    61 *** Document preparation ***
    62 
    63 * Added antiquotation @{theory name} which prints the given name,
    64 after checking that it refers to a valid ancestor theory in the
    65 current context.
    66 
    67 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    68 check the given source text as ML type/structure, printing verbatim.
    69 
    70 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    71 "c args == rhs" given in the current context.  (Any number of
    72 arguments may be given on the LHS.)
    73 
    74 
    75 
    76 *** Pure ***
    77 
    78 * code generator: consts in 'consts_code' Isar commands are now referred
    79   to by usual term syntax (including optional type annotations).
    80 
    81 * code generator: 
    82   - Isar 'definition's, 'constdef's and primitive instance definitions are added
    83     explicitly to the table of defining equations
    84   - primitive definitions are not used as defining equations by default any longer
    85   - defining equations are now definitly restricted to meta "==" and object
    86         equality "="
    87   - HOL theories have been adopted accordingly
    88 
    89 * class_package.ML offers a combination of axclasses and locales to
    90 achieve Haskell-like type classes in Isabelle.  See
    91 HOL/ex/Classpackage.thy for examples.
    92 
    93 * Yet another code generator framework allows to generate executable
    94 code for ML and Haskell (including "class"es).  A short usage sketch:
    95 
    96     internal compilation:
    97         code_gen <list of constants (term syntax)> (SML #)
    98     writing SML code to a file:
    99         code_gen <list of constants (term syntax)> (SML <filename>)
   100     writing OCaml code to a file:
   101         code_gen <list of constants (term syntax)> (OCaml <filename>)
   102     writing Haskell code to a bunch of files:
   103         code_gen <list of constants (term syntax)> (Haskell <filename>)
   104 
   105 Reasonable default setup of framework in HOL/Main.
   106 
   107 Theorem attributs for selecting and transforming function equations theorems:
   108 
   109     [code fun]:        select a theorem as function equation for a specific constant
   110     [code fun del]:    deselect a theorem as function equation for a specific constant
   111     [code inline]:     select an equation theorem for unfolding (inlining) in place
   112     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   113 
   114 User-defined serializations (target in {SML, OCaml, Haskell}):
   115 
   116     code_const <and-list of constants (term syntax)>
   117       {(target) <and-list of const target syntax>}+
   118 
   119     code_type <and-list of type constructors>
   120       {(target) <and-list of type target syntax>}+
   121 
   122     code_instance <and-list of instances>
   123       {(target)}+
   124         where instance ::= <type constructor> :: <class>
   125 
   126     code_class <and_list of classes>
   127       {(target) <and-list of class target syntax>}+
   128         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   129 
   130 code_instance and code_class only apply to target Haskell.
   131 
   132 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   133 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   134 
   135 * Command 'no_translations' removes translation rules from theory
   136 syntax.
   137 
   138 * Overloaded definitions are now actually checked for acyclic
   139 dependencies.  The overloading scheme is slightly more general than
   140 that of Haskell98, although Isabelle does not demand an exact
   141 correspondence to type class and instance declarations.
   142 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   143 exotic versions of overloading -- at the discretion of the user!
   144 
   145 Polymorphic constants are represented via type arguments, i.e. the
   146 instantiation that matches an instance against the most general
   147 declaration given in the signature.  For example, with the declaration
   148 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   149 as c(nat).  Overloading is essentially simultaneous structural
   150 recursion over such type arguments.  Incomplete specification patterns
   151 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   152 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   153 Command 'print_theory' outputs the normalized system of recursive
   154 equations, see section "definitions".
   155 
   156 * Isar: improper proof element 'guess' is like 'obtain', but derives
   157 the obtained context from the course of reasoning!  For example:
   158 
   159   assume "EX x y. A x & B y"   -- "any previous fact"
   160   then guess x and y by clarify
   161 
   162 This technique is potentially adventurous, depending on the facts and
   163 proof tools being involved here.
   164 
   165 * Isar: known facts from the proof context may be specified as literal
   166 propositions, using ASCII back-quote syntax.  This works wherever
   167 named facts used to be allowed so far, in proof commands, proof
   168 methods, attributes etc.  Literal facts are retrieved from the context
   169 according to unification of type and term parameters.  For example,
   170 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   171 theorems in the current context, then these are valid literal facts:
   172 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   173 
   174 There is also a proof method "fact" which does the same composition
   175 for explicit goal states, e.g. the following proof texts coincide with
   176 certain special cases of literal facts:
   177 
   178   have "A" by fact                 ==  note `A`
   179   have "A ==> B" by fact           ==  note `A ==> B`
   180   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   181   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   182 
   183 * Isar: ":" (colon) is no longer a symbolic identifier character in
   184 outer syntax.  Thus symbolic identifiers may be used without
   185 additional white space in declarations like this: ``assume *: A''.
   186 
   187 * Isar: 'print_facts' prints all local facts of the current context,
   188 both named and unnamed ones.
   189 
   190 * Isar: 'def' now admits simultaneous definitions, e.g.:
   191 
   192   def x == "t" and y == "u"
   193 
   194 * Isar: added command 'unfolding', which is structurally similar to
   195 'using', but affects both the goal state and facts by unfolding given
   196 rewrite rules.  Thus many occurrences of the 'unfold' method or
   197 'unfolded' attribute may be replaced by first-class proof text.
   198 
   199 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   200 and command 'unfolding' now all support object-level equalities
   201 (potentially conditional).  The underlying notion of rewrite rule is
   202 analogous to the 'rule_format' attribute, but *not* that of the
   203 Simplifier (which is usually more generous).
   204 
   205 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   206 method expression within a sandbox consisting of the first N
   207 sub-goals, which need to exist.  For example, ``simp_all [3]''
   208 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   209 simplifies all new goals that emerge from applying rule foo to the
   210 originally first one.
   211 
   212 * Isar: schematic goals are no longer restricted to higher-order
   213 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   214 expected.
   215 
   216 * Isar: the conclusion of a long theorem statement is now either
   217 'shows' (a simultaneous conjunction, as before), or 'obtains'
   218 (essentially a disjunction of cases with local parameters and
   219 assumptions).  The latter allows to express general elimination rules
   220 adequately; in this notation common elimination rules look like this:
   221 
   222   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   223     assumes "EX x. P x"
   224     obtains x where "P x"
   225 
   226   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   227     assumes "A & B"
   228     obtains A and B
   229 
   230   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   231     assumes "A | B"
   232     obtains
   233       A
   234     | B
   235 
   236 The subsequent classical rules even refer to the formal "thesis"
   237 explicitly:
   238 
   239   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   240     obtains "~ thesis"
   241 
   242   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   243     obtains "thesis ==> something"
   244 
   245 The actual proof of an 'obtains' statement is analogous to that of the
   246 Isar proof element 'obtain', only that there may be several cases.
   247 Optional case names may be specified in parentheses; these will be
   248 available both in the present proof and as annotations in the
   249 resulting rule, for later use with the 'cases' method (cf. attribute
   250 case_names).
   251 
   252 * Isar: the assumptions of a long theorem statement are available as
   253 "assms" fact in the proof context.  This is more appropriate than the
   254 (historical) "prems", which refers to all assumptions of the current
   255 context, including those from the target locale, proof body etc.
   256 
   257 * Isar: 'print_statement' prints theorems from the current theory or
   258 proof context in long statement form, according to the syntax of a
   259 top-level lemma.
   260 
   261 * Isar: 'obtain' takes an optional case name for the local context
   262 introduction rule (default "that").
   263 
   264 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   265 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   266 to occur.
   267 
   268 * Pure: syntax "CONST name" produces a fully internalized constant
   269 according to the current context.  This is particularly useful for
   270 syntax translations that should refer to internal constant
   271 representations independently of name spaces.
   272 
   273 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   274 instead of "FOO ". This allows multiple binder declarations to coexist
   275 in the same context.  INCOMPATIBILITY.
   276 
   277 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   278 primitive that also works in a locale context (both for constants and
   279 fixed variables).  Type declaration and internal syntactic
   280 representation of given constants retrieved from the context.
   281 
   282 * Isar/locales: new derived specification elements 'axiomatization',
   283 'definition', 'abbreviation', which support type-inference, admit
   284 object-level specifications (equality, equivalence).  See also the
   285 isar-ref manual.  Examples:
   286 
   287   axiomatization
   288     eq  (infix "===" 50) where
   289     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   290 
   291   definition "f x y = x + y + 1"
   292   definition g where "g x = f x x"
   293 
   294   abbreviation
   295     neq  (infix "=!=" 50) where
   296     "x =!= y == ~ (x === y)"
   297 
   298 These specifications may be also used in a locale context.  Then the
   299 constants being introduced depend on certain fixed parameters, and the
   300 constant name is qualified by the locale base name.  An internal
   301 abbreviation takes care for convenient input and output, making the
   302 parameters implicit and using the original short name.  See also
   303 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   304 entities from a monomorphic theory.
   305 
   306 Presently, abbreviations are only available 'in' a target locale, but
   307 not inherited by general import expressions.  Also note that
   308 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   309 'translations' in common applications.
   310 
   311 Concrete syntax is attached to specified constants in internal form,
   312 independently of name spaces.  The parse tree representation is
   313 slightly different -- use 'notation' instead of raw 'syntax', and
   314 'translations' with explicit "CONST" markup to accommodate this.
   315 
   316 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   317 the current context.  Print mode "no_abbrevs" prevents inversion of
   318 abbreviations on output.
   319 
   320 * Isar/locales: improved parameter handling:
   321 - use of locales "var" and "struct" no longer necessary;
   322 - parameter renamings are no longer required to be injective.
   323   This enables, for example, to define a locale for endomorphisms thus:
   324   locale endom = homom mult mult h.
   325 
   326 * Isar/locales: changed the way locales with predicates are defined.
   327 Instead of accumulating the specification, the imported expression is
   328 now an interpretation.  INCOMPATIBILITY: different normal form of
   329 locale expressions.  In particular, in interpretations of locales with
   330 predicates, goals repesenting already interpreted fragments are not
   331 removed automatically.  Use methods `intro_locales' and
   332 `unfold_locales'; see below.
   333 
   334 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   335 provide backward reasoning on locales predicates.  The methods are
   336 aware of interpretations and discharge corresponding goals.
   337 `intro_locales' is less aggressive then `unfold_locales' and does not
   338 unfold predicates to assumptions.
   339 
   340 * Isar/locales: the order in which locale fragments are accumulated
   341 has changed.  This enables to override declarations from fragments due
   342 to interpretations -- for example, unwanted simp rules.
   343 
   344 * Provers/induct: improved internal context management to support
   345 local fixes and defines on-the-fly.  Thus explicit meta-level
   346 connectives !! and ==> are rarely required anymore in inductive goals
   347 (using object-logic connectives for this purpose has been long
   348 obsolete anyway).  The subsequent proof patterns illustrate advanced
   349 techniques of natural induction; general datatypes and inductive sets
   350 work analogously (see also src/HOL/Lambda for realistic examples).
   351 
   352 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   353 parameters:
   354 
   355   lemma
   356     fixes n :: nat and x :: 'a
   357     assumes a: "A n x"
   358     shows "P n x"
   359     using a                     -- {* make induct insert fact a *}
   360   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   361     case 0
   362     show ?case sorry
   363   next
   364     case (Suc n)
   365     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   366     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   367     show ?case sorry
   368   qed
   369 
   370 (2) This is how to perform induction over ``expressions of a certain
   371 form'', using a locally defined inductive parameter n == "a x"
   372 together with strengthening (the latter is usually required to get
   373 sufficiently flexible induction hypotheses):
   374 
   375   lemma
   376     fixes a :: "'a => nat"
   377     assumes a: "A (a x)"
   378     shows "P (a x)"
   379     using a
   380   proof (induct n == "a x" arbitrary: x)
   381     ...
   382 
   383 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   384 particular technique.
   385 
   386 (3) This is how to perform existential reasoning ('obtains' or
   387 'obtain') by induction, while avoiding explicit object-logic
   388 encodings:
   389 
   390   lemma
   391     fixes n :: nat
   392     obtains x :: 'a where "P n x" and "Q n x"
   393   proof (induct n arbitrary: thesis)
   394     case 0
   395     obtain x where "P 0 x" and "Q 0 x" sorry
   396     then show thesis by (rule 0)
   397   next
   398     case (Suc n)
   399     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   400     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   401     then show thesis by (rule Suc.prems)
   402   qed
   403 
   404 Here the 'arbitrary: thesis' specification essentially modifies the
   405 scope of the formal thesis parameter, in order to the get the whole
   406 existence statement through the induction as expected.
   407 
   408 * Provers/induct: mutual induction rules are now specified as a list
   409 of rule sharing the same induction cases.  HOL packages usually
   410 provide foo_bar.inducts for mutually defined items foo and bar
   411 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   412 specify mutual induction rules differently, i.e. like this:
   413 
   414   (induct rule: foo_bar.inducts)
   415   (induct set: foo bar)
   416   (induct type: foo bar)
   417 
   418 The ML function ProjectRule.projections turns old-style rules into the
   419 new format.
   420 
   421 * Provers/induct: improved handling of simultaneous goals.  Instead of
   422 introducing object-level conjunction, the statement is now split into
   423 several conclusions, while the corresponding symbolic cases are
   424 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   425 explicitly.  For example:
   426 
   427   lemma
   428     fixes n :: nat
   429     shows "P n" and "Q n"
   430   proof (induct n)
   431     case 0 case 1
   432     show "P 0" sorry
   433   next
   434     case 0 case 2
   435     show "Q 0" sorry
   436   next
   437     case (Suc n) case 1
   438     note `P n` and `Q n`
   439     show "P (Suc n)" sorry
   440   next
   441     case (Suc n) case 2
   442     note `P n` and `Q n`
   443     show "Q (Suc n)" sorry
   444   qed
   445 
   446 The split into subcases may be deferred as follows -- this is
   447 particularly relevant for goal statements with local premises.
   448 
   449   lemma
   450     fixes n :: nat
   451     shows "A n ==> P n" and "B n ==> Q n"
   452   proof (induct n)
   453     case 0
   454     {
   455       case 1
   456       note `A 0`
   457       show "P 0" sorry
   458     next
   459       case 2
   460       note `B 0`
   461       show "Q 0" sorry
   462     }
   463   next
   464     case (Suc n)
   465     note `A n ==> P n` and `B n ==> Q n`
   466     {
   467       case 1
   468       note `A (Suc n)`
   469       show "P (Suc n)" sorry
   470     next
   471       case 2
   472       note `B (Suc n)`
   473       show "Q (Suc n)" sorry
   474     }
   475   qed
   476 
   477 If simultaneous goals are to be used with mutual rules, the statement
   478 needs to be structured carefully as a two-level conjunction, using
   479 lists of propositions separated by 'and':
   480 
   481   lemma
   482     shows "a : A ==> P1 a"
   483           "a : A ==> P2 a"
   484       and "b : B ==> Q1 b"
   485           "b : B ==> Q2 b"
   486           "b : B ==> Q3 b"
   487   proof (induct set: A B)
   488 
   489 * Provers/induct: support coinduction as well.  See
   490 src/HOL/Library/Coinductive_List.thy for various examples.
   491 
   492 * Attribute "symmetric" produces result with standardized schematic
   493 variables (index 0).  Potential INCOMPATIBILITY.
   494 
   495 * Simplifier: by default the simplifier trace only shows top level
   496 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   497 default. Thus there is less danger of being flooded by the trace. The
   498 trace indicates where parts have been suppressed.
   499   
   500 * Provers/classical: removed obsolete classical version of elim_format
   501 attribute; classical elim/dest rules are now treated uniformly when
   502 manipulating the claset.
   503 
   504 * Provers/classical: stricter checks to ensure that supplied intro,
   505 dest and elim rules are well-formed; dest and elim rules must have at
   506 least one premise.
   507 
   508 * Provers/classical: attributes dest/elim/intro take an optional
   509 weight argument for the rule (just as the Pure versions).  Weights are
   510 ignored by automated tools, but determine the search order of single
   511 rule steps.
   512 
   513 * Syntax: input syntax now supports dummy variable binding "%_. b",
   514 where the body does not mention the bound variable.  Note that dummy
   515 patterns implicitly depend on their context of bounds, which makes
   516 "{_. _}" match any set comprehension as expected.  Potential
   517 INCOMPATIBILITY -- parse translations need to cope with syntactic
   518 constant "_idtdummy" in the binding position.
   519 
   520 * Syntax: removed obsolete syntactic constant "_K" and its associated
   521 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   522 for example "A -> B" => "Pi A (%_. B)".
   523 
   524 * Pure: 'class_deps' command visualizes the subclass relation, using
   525 the graph browser tool.
   526 
   527 * Pure: 'print_theory' now suppresses entities with internal name
   528 (trailing "_") by default; use '!' option for full details.
   529 
   530 
   531 *** HOL ***
   532 
   533 * Constant renames due to introduction of canonical name prefixing for
   534   class package:
   535 
   536     HOL.abs ~> HOL.minus_class.abs
   537     HOL.divide ~> HOL.divide_class.divide
   538     Nat.power ~> Nat.power_class.power
   539     Nat.size ~> Nat.size_class.size
   540     Numeral.number_of ~> Numeral.number_class.number_of
   541 
   542 * case expressions and primrec: missing cases now mapped to "undefined"
   543 instead of "arbitrary"
   544 
   545 * new constant "undefined" with axiom "undefined x = undefined"
   546 
   547 * new class "default" with associated constant "default"
   548 
   549 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   550     when generating code.
   551 
   552 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   553     when generating code.
   554 
   555 * Library/Commutative_Ring.thy: switched from recdef to function package;
   556     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   557 
   558 * Some steps towards more uniform lattice theory development in HOL.
   559 
   560     constants "meet" and "join" now named "inf" and "sup"
   561     constant "Meet" now named "Inf"
   562 
   563     classes "meet_semilorder" and "join_semilorder" now named
   564       "lower_semilattice" and "upper_semilattice"
   565     class "lorder" now named "lattice"
   566     class "comp_lat" now named "complete_lattice"
   567 
   568     Instantiation of lattice classes allows explicit definitions
   569     for "inf" and "sup" operations.
   570 
   571   INCOMPATIBILITY. Theorem renames:
   572 
   573     meet_left_le            ~> inf_le1
   574     meet_right_le           ~> inf_le2
   575     join_left_le            ~> sup_ge1
   576     join_right_le           ~> sup_ge2
   577     meet_join_le            ~> inf_sup_ord
   578     le_meetI                ~> le_infI
   579     join_leI                ~> le_supI
   580     le_meet                 ~> le_inf_iff
   581     le_join                 ~> ge_sup_conv
   582     meet_idempotent         ~> inf_idem
   583     join_idempotent         ~> sup_idem
   584     meet_comm               ~> inf_commute
   585     join_comm               ~> sup_commute
   586     meet_leI1               ~> le_infI1
   587     meet_leI2               ~> le_infI2
   588     le_joinI1               ~> le_supI1
   589     le_joinI2               ~> le_supI2
   590     meet_assoc              ~> inf_assoc
   591     join_assoc              ~> sup_assoc
   592     meet_left_comm          ~> inf_left_commute
   593     meet_left_idempotent    ~> inf_left_idem
   594     join_left_comm          ~> sup_left_commute
   595     join_left_idempotent    ~> sup_left_idem
   596     meet_aci                ~> inf_aci
   597     join_aci                ~> sup_aci
   598     le_def_meet             ~> le_iff_inf
   599     le_def_join             ~> le_iff_sup
   600     join_absorp2            ~> sup_absorb2
   601     join_absorp1            ~> sup_absorb1
   602     meet_absorp1            ~> inf_absorb1
   603     meet_absorp2            ~> inf_absorb2
   604     meet_join_absorp        ~> inf_sup_absorb
   605     join_meet_absorp        ~> sup_inf_absorb
   606     distrib_join_le         ~> distrib_sup_le
   607     distrib_meet_le         ~> distrib_inf_le
   608 
   609     add_meet_distrib_left   ~> add_inf_distrib_left
   610     add_join_distrib_left   ~> add_sup_distrib_left
   611     is_join_neg_meet        ~> is_join_neg_inf
   612     is_meet_neg_join        ~> is_meet_neg_sup
   613     add_meet_distrib_right  ~> add_inf_distrib_right
   614     add_join_distrib_right  ~> add_sup_distrib_right
   615     add_meet_join_distribs  ~> add_sup_inf_distribs
   616     join_eq_neg_meet        ~> sup_eq_neg_inf
   617     meet_eq_neg_join        ~> inf_eq_neg_sup
   618     add_eq_meet_join        ~> add_eq_inf_sup
   619     meet_0_imp_0            ~> inf_0_imp_0
   620     join_0_imp_0            ~> sup_0_imp_0
   621     meet_0_eq_0             ~> inf_0_eq_0
   622     join_0_eq_0             ~> sup_0_eq_0
   623     neg_meet_eq_join        ~> neg_inf_eq_sup
   624     neg_join_eq_meet        ~> neg_sup_eq_inf
   625     join_eq_if              ~> sup_eq_if
   626 
   627     mono_meet               ~> mono_inf
   628     mono_join               ~> mono_sup
   629     meet_bool_eq            ~> inf_bool_eq
   630     join_bool_eq            ~> sup_bool_eq
   631     meet_fun_eq             ~> inf_fun_eq
   632     join_fun_eq             ~> sup_fun_eq
   633     meet_set_eq             ~> inf_set_eq
   634     join_set_eq             ~> sup_set_eq
   635     meet1_iff               ~> inf1_iff
   636     meet2_iff               ~> inf2_iff
   637     meet1I                  ~> inf1I
   638     meet2I                  ~> inf2I
   639     meet1D1                 ~> inf1D1
   640     meet2D1                 ~> inf2D1
   641     meet1D2                 ~> inf1D2
   642     meet2D2                 ~> inf2D2
   643     meet1E                  ~> inf1E
   644     meet2E                  ~> inf2E
   645     join1_iff               ~> sup1_iff
   646     join2_iff               ~> sup2_iff
   647     join1I1                 ~> sup1I1
   648     join2I1                 ~> sup2I1
   649     join1I1                 ~> sup1I1
   650     join2I2                 ~> sup1I2
   651     join1CI                 ~> sup1CI
   652     join2CI                 ~> sup2CI
   653     join1E                  ~> sup1E
   654     join2E                  ~> sup2E
   655 
   656     is_meet_Meet            ~> is_meet_Inf
   657     Meet_bool_def           ~> Inf_bool_def
   658     Meet_fun_def            ~> Inf_fun_def
   659     Meet_greatest           ~> Inf_greatest
   660     Meet_lower              ~> Inf_lower
   661     Meet_set_def            ~> Inf_set_def
   662 
   663     listsp_meetI            ~> listsp_infI
   664     listsp_meet_eq          ~> listsp_inf_eq
   665 
   666     meet_min                ~> inf_min
   667     join_max                ~> sup_max
   668 
   669 * Classes "order" and "linorder": facts "refl", "trans" and
   670 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   671 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   672 
   673 * Classes "order" and "linorder": 
   674 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   675 proofs changed.
   676 
   677 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   678 INCOMPATIBILITY.
   679 
   680 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   681 INCOMPATIBILITY.
   682 
   683 * Added syntactic class "size"; overloaded constant "size" now has
   684 type "'a::size ==> bool"
   685 
   686 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   687 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   688 
   689 * Added method "lexicographic_order" automatically synthesizes
   690 termination relations as lexicographic combinations of size measures
   691 -- 'function' package.
   692 
   693 * HOL/records: generalised field-update to take a function on the
   694 field rather than the new value: r(|A := x|) is translated to A_update
   695 (K x) r The K-combinator that is internally used is called K_record.
   696 INCOMPATIBILITY: Usage of the plain update functions has to be
   697 adapted.
   698  
   699 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   700 0 * x = 0, which are required for a semiring.  Richer structures do
   701 not inherit from semiring_0 anymore, because this property is a
   702 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   703 semiring_0, there is more to prove, but this is mostly trivial.
   704 
   705 * axclass "recpower" was generalized to arbitrary monoids, not just
   706 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   707 commutativity or a semiring property, add the corresponding classes.
   708 
   709 * Unified locale partial_order with class definition (cf. theory
   710 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   711 
   712 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   713 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   714 Isar level, use abbreviations instead.
   715 
   716 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   717 rarely occuring name references (e.g. ``List.op mem.simps'') require
   718 renaming (e.g. ``List.memberl.simps'').
   719 
   720 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   721 INCOMPATIBILITY.
   722 
   723 * Added theory Code_Generator providing class 'eq', allowing for code
   724 generation with polymorphic equality.
   725 
   726 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   727 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   728 significant changes for setting up numeral syntax for types:
   729 
   730   - new constants Numeral.pred and Numeral.succ instead
   731       of former Numeral.bin_pred and Numeral.bin_succ.
   732   - Use integer operations instead of bin_add, bin_mult and so on.
   733   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   734   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   735 
   736 See HOL/Integ/IntArith.thy for an example setup.
   737 
   738 * New top level command 'normal_form' computes the normal form of a
   739 term that may contain free variables. For example ``normal_form
   740 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   741 suitable for heavy-duty computations because the functions are
   742 compiled to ML first.
   743 
   744 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   745 25 like -->); output depends on the "iff" print_mode, the default is
   746 "A = B" (with priority 50).
   747 
   748 * Renamed constants in HOL.thy and Orderings.thy:
   749     op +   ~> HOL.plus_class.plus
   750     op -   ~> HOL.minus_class.minus
   751     uminus ~> HOL.minus_class.uminus
   752     op *   ~> HOL.times_class.times
   753     op <   ~> Orderings.ord_class.less
   754     op <=  ~> Orderings.ord_class.less_eq
   755 
   756 Adaptions may be required in the following cases:
   757 
   758 a) User-defined constants using any of the names "plus", "minus", "times",
   759 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   760 may go wrong.
   761 INCOMPATIBILITY: use more specific names.
   762 
   763 b) Variables named "plus", "minus", "times", "less", "less_eq"
   764 INCOMPATIBILITY: use more specific names.
   765 
   766 c) Permutative equations (e.g. "a + b = b + a")
   767 Since the change of names also changes the order of terms, permutative
   768 rewrite rules may get applied in a different order. Experience shows that
   769 this is rarely the case (only two adaptions in the whole Isabelle
   770 distribution).
   771 INCOMPATIBILITY: rewrite proofs
   772 
   773 d) ML code directly refering to constant names
   774 This in general only affects hand-written proof tactics, simprocs and so on.
   775 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   776 of const_name ML antiquotations.
   777 
   778 * Relations less (<) and less_eq (<=) are also available on type bool.
   779 Modified syntax to disallow nesting without explicit parentheses,
   780 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   781 
   782 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   783 
   784 * Relation composition operator "op O" now has precedence 75 and binds
   785 stronger than union and intersection. INCOMPATIBILITY.
   786 
   787 * The old set interval syntax "{m..n(}" (and relatives) has been
   788 removed.  Use "{m..<n}" (and relatives) instead.
   789 
   790 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   791 "t = s" to False (by simproc "neq_simproc").  For backward
   792 compatibility this can be disabled by ML "reset use_neq_simproc".
   793 
   794 * "m dvd n" where m and n are numbers is evaluated to True/False by
   795 simp.
   796 
   797 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   798 
   799 * Theorem setsum_mult renamed to setsum_right_distrib.
   800 
   801 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   802 ``rule'' method.
   803 
   804 * Reimplemented methods ``sat'' and ``satx'', with several
   805 improvements: goals no longer need to be stated as "<prems> ==>
   806 False", equivalences (i.e. "=" on type bool) are handled, variable
   807 names of the form "lit_<n>" are no longer reserved, significant
   808 speedup.
   809 
   810 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   811 zChaff is still supported as well.
   812 
   813 * 'inductive' and 'datatype': provide projections of mutual rules,
   814 bundled as foo_bar.inducts;
   815 
   816 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   817 Library.
   818 
   819 * Library: moved theory Accessible_Part to main HOL.
   820 
   821 * Library: added theory Coinductive_List of potentially infinite lists
   822 as greatest fixed-point.
   823 
   824 * Library: added theory AssocList which implements (finite) maps as
   825 association lists.
   826 
   827 * Added proof method ``evaluation'' for efficiently solving a goal
   828 (i.e. a boolean expression) by compiling it to ML. The goal is
   829 "proved" (via an oracle) if it evaluates to True.
   830 
   831 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   832 also when invoked by the simplifier.  This results in the simplifier
   833 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   834 fast_arith_split_limit to 0 to obtain the old behavior.
   835 
   836 * Support for hex (0x20) and binary (0b1001) numerals.
   837 
   838 * New method: reify eqs (t), where eqs are equations for an
   839 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   840 parameter, computes a term s::'b and a list xs::'a list and proves the
   841 theorem I xs s = t. This is also known as reification or quoting. The
   842 resulting theorem is applied to the subgoal to substitute t with I xs
   843 s.  If t is omitted, the subgoal itself is reified.
   844 
   845 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   846 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   847 where f is supposed to be a computable function (in the sense of code
   848 generattion). The method uses reify to compute s and xs as above then
   849 applies corr_thm and uses normalization by evaluation to "prove" f s =
   850 r and finally gets the theorem t = r, which is again applied to the
   851 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   852 
   853 * Reflection: Automatic refification now handels binding, an example
   854 is available in HOL/ex/ReflectionEx.thy
   855 
   856 
   857 *** HOL-Algebra ***
   858 
   859 * Formalisation of ideals and the quotient construction over rings.
   860 
   861 * Order and lattice theory no longer based on records.
   862 INCOMPATIBILITY.
   863 
   864 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   865 greatest_closed.  INCOMPATIBILITY.
   866 
   867 * Method algebra is now set up via an attribute.  For examples see
   868 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   869 of algebraic structures.
   870 
   871 * Renamed theory CRing to Ring.
   872 
   873 
   874 *** HOL-Complex ***
   875 
   876 * Theory Real: new method ferrack implements quantifier elimination
   877 for linear arithmetic over the reals. The quantifier elimination
   878 feature is used only for decision, for compatibility with arith. This
   879 means a goal is either solved or left unchanged, no simplification.
   880 
   881 * Hyperreal: Functions root and sqrt are now defined on negative real
   882 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
   883 Nonnegativity side conditions have been removed from many lemmas, so
   884 that more subgoals may now be solved by simplification; potential
   885 INCOMPATIBILITY.
   886 
   887 * Real: New axiomatic classes formalize real normed vector spaces and
   888 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   889 and norm :: 'a => real.
   890 
   891 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   892 from reals into other types. The overloaded constant Reals :: 'a set
   893 is now defined as range of_real; potential INCOMPATIBILITY.
   894 
   895 * Real: ML code generation is supported now and hence also quickcheck.
   896 Reals are implemented as arbitrary precision rationals.
   897 
   898 * Hyperreal: Several constants that previously worked only for the
   899 reals have been generalized, so they now work over arbitrary vector
   900 spaces. Type annotations may need to be added in some cases; potential
   901 INCOMPATIBILITY.
   902 
   903   Infinitesimal  :: ('a::real_normed_vector) star set
   904   HFinite        :: ('a::real_normed_vector) star set
   905   HInfinite      :: ('a::real_normed_vector) star set
   906   approx         :: ('a::real_normed_vector) star => 'a star => bool
   907   monad          :: ('a::real_normed_vector) star => 'a star set
   908   galaxy         :: ('a::real_normed_vector) star => 'a star set
   909   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
   910   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   911   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   912   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   913   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   914   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   915   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   916   sgn            :: 'a::real_normed_vector => 'a
   917 
   918 * Complex: Some complex-specific constants are now abbreviations for
   919 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   920 hnorm.  Other constants have been entirely removed in favor of the
   921 polymorphic versions (INCOMPATIBILITY):
   922 
   923   approx        <-- capprox
   924   HFinite       <-- CFinite
   925   HInfinite     <-- CInfinite
   926   Infinitesimal <-- CInfinitesimal
   927   monad         <-- cmonad
   928   galaxy        <-- cgalaxy
   929   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   930   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   931   (ns)deriv     <-- (ns)cderiv
   932 
   933 
   934 *** ML ***
   935 
   936 * Context data interfaces (Theory/Proof/GenericDataFun): removed
   937 name/print, uninitialized data defaults to ad-hoc copy of empty value,
   938 init only required for impure data.  INCOMPATIBILITY: empty really
   939 need to be empty (no dependencies on theory content!)
   940 
   941 * ML within Isar: antiquotations allow to embed statically-checked
   942 formal entities in the source, referring to the context available at
   943 compile-time.  For example:
   944 
   945 ML {* @{typ "'a => 'b"} *}
   946 ML {* @{term "%x. x"} *}
   947 ML {* @{prop "x == y"} *}
   948 ML {* @{ctyp "'a => 'b"} *}
   949 ML {* @{cterm "%x. x"} *}
   950 ML {* @{cprop "x == y"} *}
   951 ML {* @{thm asm_rl} *}
   952 ML {* @{thms asm_rl} *}
   953 ML {* @{const_name c} *}
   954 ML {* @{const_syntax c} *}
   955 ML {* @{context} *}
   956 ML {* @{theory} *}
   957 ML {* @{theory Pure} *}
   958 ML {* @{simpset} *}
   959 ML {* @{claset} *}
   960 ML {* @{clasimpset} *}
   961 
   962 The same works for sources being ``used'' within an Isar context.
   963 
   964 * ML in Isar: improved error reporting; extra verbosity with
   965 Toplevel.debug enabled.
   966 
   967 * Pure/library:
   968 
   969   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   970   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   971 
   972 The semantics of "burrow" is: "take a function with *simulatanously*
   973 transforms a list of value, and apply it *simulatanously* to a list of
   974 list of values of the appropriate type". Compare this with "map" which
   975 would *not* apply its argument function simulatanously but in
   976 sequence; "fold_burrow" has an additional context.
   977 
   978 * Pure/library: functions map2 and fold2 with curried syntax for
   979 simultanous mapping and folding:
   980 
   981     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   982     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   983 
   984 * Pure/library: indexed lists - some functions in the Isabelle library
   985 treating lists over 'a as finite mappings from [0...n] to 'a have been
   986 given more convenient names and signatures reminiscent of similar
   987 functions for alists, tables, etc:
   988 
   989   val nth: 'a list -> int -> 'a 
   990   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   991   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   992 
   993 Note that fold_index starts counting at index 0, not 1 like foldln
   994 used to.
   995 
   996 * Pure/library: added general ``divide_and_conquer'' combinator on
   997 lists.
   998 
   999 * Pure/General/table.ML: the join operations now works via exceptions
  1000 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1001 admits slightly more efficient complex applications.
  1002 
  1003 * Pure: datatype Context.generic joins theory/Proof.context and
  1004 provides some facilities for code that works in either kind of
  1005 context, notably GenericDataFun for uniform theory and proof data.
  1006 
  1007 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1008 use Context.generic instead of just theory.
  1009 
  1010 * Pure: simplified internal attribute type, which is now always
  1011 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1012 vs. local (Proof.context) attributes have been discontinued, while
  1013 minimizing code duplication.  Thm.rule_attribute and
  1014 Thm.declaration_attribute build canonical attributes; see also
  1015 structure Context for further operations on Context.generic, notably
  1016 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1017 declarations and definitions.
  1018 
  1019 * Pure/kernel: consts certification ignores sort constraints given in
  1020 signature declarations.  (This information is not relevant to the
  1021 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1022 potential INCOMPATIBILITY.
  1023 
  1024 * Pure: axiomatic type classes are now purely definitional, with
  1025 explicit proofs of class axioms and super class relations performed
  1026 internally.  See Pure/axclass.ML for the main internal interfaces --
  1027 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1028 AxClass.axiomatize_class/classrel/arity supercede
  1029 Sign.add_classes/classrel/arities.
  1030 
  1031 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1032 global/local versions on theory vs. Proof.context have been
  1033 discontinued; Attrib.syntax and Method.syntax have been adapted
  1034 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1035 attributes, methods, etc.
  1036 
  1037 * Pure: several functions of signature "... -> theory -> theory * ..."
  1038 have been reoriented to "... -> theory -> ... * theory" in order to
  1039 allow natural usage in combination with the ||>, ||>>, |-> and
  1040 fold_map combinators.
  1041 
  1042 * Pure: official theorem names (closed derivations) and additional
  1043 comments (tags) are now strictly separate.  Name hints -- which are
  1044 maintained as tags -- may be attached any time without affecting the
  1045 derivation.
  1046 
  1047 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1048 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1049 achieve the old behaviour.
  1050 
  1051 * Pure: the "Goal" constant is now called "prop", supporting a
  1052 slightly more general idea of ``protecting'' meta-level rule
  1053 statements.
  1054 
  1055 * Pure: Logic.(un)varify only works in a global context, which is now
  1056 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1057 Logic.legacy_(un)varify as temporary workaround.
  1058 
  1059 * Pure: structure Name provides scalable operations for generating
  1060 internal variable names, notably Name.variants etc.  This replaces
  1061 some popular functions from term.ML:
  1062 
  1063   Term.variant		->  Name.variant
  1064   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1065   Term.invent_names	->  Name.invent_list
  1066 
  1067 Note that low-level renaming rarely occurs in new code -- operations
  1068 from structure Variable are used instead (see below).
  1069 
  1070 * Pure: structure Variable provides fundamental operations for proper
  1071 treatment of fixed/schematic variables in a context.  For example,
  1072 Variable.import introduces fixes for schematics of given facts and
  1073 Variable.export reverses the effect (up to renaming) -- this replaces
  1074 various freeze_thaw operations.
  1075 
  1076 * Pure: structure Goal provides simple interfaces for
  1077 init/conclude/finish and tactical prove operations (replacing former
  1078 Tactic.prove).  Goal.prove is the canonical way to prove results
  1079 within a given context; Goal.prove_global is a degraded version for
  1080 theory level goals, including a global Drule.standard.  Note that
  1081 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1082 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1083 in a locale context).
  1084 
  1085 * Isar: simplified treatment of user-level errors, using exception
  1086 ERROR of string uniformly.  Function error now merely raises ERROR,
  1087 without any side effect on output channels.  The Isar toplevel takes
  1088 care of proper display of ERROR exceptions.  ML code may use plain
  1089 handle/can/try; cat_error may be used to concatenate errors like this:
  1090 
  1091   ... handle ERROR msg => cat_error msg "..."
  1092 
  1093 Toplevel ML code (run directly or through the Isar toplevel) may be
  1094 embedded into the Isar toplevel with exception display/debug like
  1095 this:
  1096 
  1097   Isar.toplevel (fn () => ...)
  1098 
  1099 INCOMPATIBILITY, removed special transform_error facilities, removed
  1100 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1101 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1102 -- use plain ERROR instead.
  1103 
  1104 * Isar: theory setup now has type (theory -> theory), instead of a
  1105 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1106 
  1107 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1108 subject to ProofContext.debug/verbose flags.
  1109 
  1110 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1111 theory before entering a proof state.  Transactions now always see a
  1112 quasi-functional intermediate checkpoint, both in interactive and
  1113 batch mode.
  1114 
  1115 * Simplifier: the simpset of a running simplification process now
  1116 contains a proof context (cf. Simplifier.the_context), which is the
  1117 very context that the initial simpset has been retrieved from (by
  1118 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1119 (solver, looper etc.) may depend on arbitrary proof data.
  1120 
  1121 * Simplifier.inherit_context inherits the proof context (plus the
  1122 local bounds) of the current simplification process; any simproc
  1123 etc. that calls the Simplifier recursively should do this!  Removed
  1124 former Simplifier.inherit_bounds, which is already included here --
  1125 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1126 specify an explicit context using Simplifier.context/theory_context.
  1127 
  1128 * Simplifier/Classical Reasoner: more abstract interfaces
  1129 change_simpset/claset for modifying the simpset/claset reference of a
  1130 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1131 INCOMPATIBILITY.
  1132 
  1133 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1134 "Trueprop" etc.
  1135 
  1136 
  1137 *** System ***
  1138 
  1139 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1140 locations -- now includes the Isabelle version identifier as well.
  1141 This simplifies use of multiple Isabelle installations.
  1142 
  1143 * isabelle-process: option -S (secure mode) disables some critical
  1144 operations, notably runtime compilation and evaluation of ML source
  1145 code.
  1146 
  1147 
  1148 New in Isabelle2005 (October 2005)
  1149 ----------------------------------
  1150 
  1151 *** General ***
  1152 
  1153 * Theory headers: the new header syntax for Isar theories is
  1154 
  1155   theory <name>
  1156   imports <theory1> ... <theoryN>
  1157   uses <file1> ... <fileM>
  1158   begin
  1159 
  1160 where the 'uses' part is optional.  The previous syntax
  1161 
  1162   theory <name> = <theory1> + ... + <theoryN>:
  1163 
  1164 will disappear in the next release.  Use isatool fixheaders to convert
  1165 existing theory files.  Note that there is no change in ancient
  1166 non-Isar theories now, but these will disappear soon.
  1167 
  1168 * Theory loader: parent theories can now also be referred to via
  1169 relative and absolute paths.
  1170 
  1171 * Command 'find_theorems' searches for a list of criteria instead of a
  1172 list of constants. Known criteria are: intro, elim, dest, name:string,
  1173 simp:term, and any term. Criteria can be preceded by '-' to select
  1174 theorems that do not match. Intro, elim, dest select theorems that
  1175 match the current goal, name:s selects theorems whose fully qualified
  1176 name contain s, and simp:term selects all simplification rules whose
  1177 lhs match term.  Any other term is interpreted as pattern and selects
  1178 all theorems matching the pattern. Available in ProofGeneral under
  1179 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1180 
  1181   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1182 
  1183 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1184 matching the current goal as introduction rule and not having "HOL."
  1185 in their name (i.e. not being defined in theory HOL).
  1186 
  1187 * Command 'thms_containing' has been discontinued in favour of
  1188 'find_theorems'; INCOMPATIBILITY.
  1189 
  1190 * Communication with Proof General is now 8bit clean, which means that
  1191 Unicode text in UTF-8 encoding may be used within theory texts (both
  1192 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1193 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1194 
  1195   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1196   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1197 
  1198 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1199 Classical Reasoner.  Typical big applications run around 2 times
  1200 faster.
  1201 
  1202 
  1203 *** Document preparation ***
  1204 
  1205 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1206 of raw sources.  Only those symbols that do not require additional
  1207 LaTeX packages (depending on comments in isabellesym.sty) are
  1208 displayed properly, everything else is left verbatim.  isatool display
  1209 and isatool print are used as front ends (these are subject to the
  1210 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1211 
  1212 * Command tags control specific markup of certain regions of text,
  1213 notably folding and hiding.  Predefined tags include "theory" (for
  1214 theory begin and end), "proof" for proof commands, and "ML" for
  1215 commands involving ML code; the additional tags "visible" and
  1216 "invisible" are unused by default.  Users may give explicit tag
  1217 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1218 interpretation of tags is determined by the LaTeX job during document
  1219 preparation: see option -V of isatool usedir, or options -n and -t of
  1220 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1221 \isadroptag.
  1222 
  1223 Several document versions may be produced at the same time via isatool
  1224 usedir (the generated index.html will link all of them).  Typical
  1225 specifications include ''-V document=theory,proof,ML'' to present
  1226 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1227 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1228 these parts without any formal replacement text.  The Isabelle site
  1229 default settings produce ''document'' and ''outline'' versions as
  1230 specified above.
  1231 
  1232 * Several new antiquotations:
  1233 
  1234   @{term_type term} prints a term with its type annotated;
  1235 
  1236   @{typeof term} prints the type of a term;
  1237 
  1238   @{const const} is the same as @{term const}, but checks that the
  1239   argument is a known logical constant;
  1240 
  1241   @{term_style style term} and @{thm_style style thm} print a term or
  1242   theorem applying a "style" to it
  1243 
  1244   @{ML text}
  1245 
  1246 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1247 definitions, equations, inequations etc., 'concl' printing only the
  1248 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1249 to print the specified premise.  TermStyle.add_style provides an ML
  1250 interface for introducing further styles.  See also the "LaTeX Sugar"
  1251 document practical applications.  The ML antiquotation prints
  1252 type-checked ML expressions verbatim.
  1253 
  1254 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1255 and 'text' support optional locale specification '(in loc)', which
  1256 specifies the default context for interpreting antiquotations.  For
  1257 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1258 
  1259 * Option 'locale=NAME' of antiquotations specifies an alternative
  1260 context interpreting the subsequent argument.  For example: @{thm
  1261 [locale=lattice] inf_assoc}.
  1262 
  1263 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1264 a proof context.
  1265 
  1266 * Proper output of antiquotations for theory commands involving a
  1267 proof context (such as 'locale' or 'theorem (in loc) ...').
  1268 
  1269 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1270 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1271 
  1272 * isatool usedir: new option -C (default true) controls whether option
  1273 -D should include a copy of the original document directory; -C false
  1274 prevents unwanted effects such as copying of administrative CVS data.
  1275 
  1276 
  1277 *** Pure ***
  1278 
  1279 * Considerably improved version of 'constdefs' command.  Now performs
  1280 automatic type-inference of declared constants; additional support for
  1281 local structure declarations (cf. locales and HOL records), see also
  1282 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1283 sequential dependencies of definitions within a single 'constdefs'
  1284 section; moreover, the declared name needs to be an identifier.  If
  1285 all fails, consider to fall back on 'consts' and 'defs' separately.
  1286 
  1287 * Improved indexed syntax and implicit structures.  First of all,
  1288 indexed syntax provides a notational device for subscripted
  1289 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1290 expressions.  Secondly, in a local context with structure
  1291 declarations, number indexes \<^sub>n or the empty index (default
  1292 number 1) refer to a certain fixed variable implicitly; option
  1293 show_structs controls printing of implicit structures.  Typical
  1294 applications of these concepts involve record types and locales.
  1295 
  1296 * New command 'no_syntax' removes grammar declarations (and
  1297 translations) resulting from the given syntax specification, which is
  1298 interpreted in the same manner as for the 'syntax' command.
  1299 
  1300 * 'Advanced' translation functions (parse_translation etc.) may depend
  1301 on the signature of the theory context being presently used for
  1302 parsing/printing, see also isar-ref manual.
  1303 
  1304 * Improved 'oracle' command provides a type-safe interface to turn an
  1305 ML expression of type theory -> T -> term into a primitive rule of
  1306 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1307 is already included here); see also FOL/ex/IffExample.thy;
  1308 INCOMPATIBILITY.
  1309 
  1310 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1311 before); "cI" is no longer bound, use "c.intro" instead.
  1312 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1313 axclasses vs. locales.
  1314 
  1315 * Improved internal renaming of symbolic identifiers -- attach primes
  1316 instead of base 26 numbers.
  1317 
  1318 * New flag show_question_marks controls printing of leading question
  1319 marks in schematic variable names.
  1320 
  1321 * In schematic variable names, *any* symbol following \<^isub> or
  1322 \<^isup> is now treated as part of the base name.  For example, the
  1323 following works without printing of awkward ".0" indexes:
  1324 
  1325   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1326     by simp
  1327 
  1328 * Inner syntax includes (*(*nested*) comments*).
  1329 
  1330 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1331 annotations as "(00...)".
  1332 
  1333 * Clear separation of logical types and nonterminals, where the latter
  1334 may only occur in 'syntax' specifications or type abbreviations.
  1335 Before that distinction was only partially implemented via type class
  1336 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1337 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1338 exotic syntax specifications may require further adaption
  1339 (e.g. Cube/Cube.thy).
  1340 
  1341 * Removed obsolete type class "logic", use the top sort {} instead.
  1342 Note that non-logical types should be declared as 'nonterminals'
  1343 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1344 specifications.
  1345 
  1346 * Attributes 'induct' and 'cases': type or set names may now be
  1347 locally fixed variables as well.
  1348 
  1349 * Simplifier: can now control the depth to which conditional rewriting
  1350 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1351 Limit.
  1352 
  1353 * Simplifier: simplification procedures may now take the current
  1354 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1355 interface), which is very useful for calling the Simplifier
  1356 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1357 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1358 low-level mk_simproc no longer applies Logic.varify internally, to
  1359 allow for use in a context of fixed variables.
  1360 
  1361 * thin_tac now works even if the assumption being deleted contains !!
  1362 or ==>.  More generally, erule now works even if the major premise of
  1363 the elimination rule contains !! or ==>.
  1364 
  1365 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1366 
  1367 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1368 from Pure, which contains all common declarations already.  Both
  1369 theories are defined via plain Isabelle/Isar .thy files.
  1370 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1371 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1372 use isatool fixcpure to adapt your theory and ML sources.
  1373 
  1374 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1375 selections of theorems in named facts via index ranges.
  1376 
  1377 * 'print_theorems': in theory mode, really print the difference
  1378 wrt. the last state (works for interactive theory development only),
  1379 in proof mode print all local facts (cf. 'print_facts');
  1380 
  1381 * 'hide': option '(open)' hides only base names.
  1382 
  1383 * More efficient treatment of intermediate checkpoints in interactive
  1384 theory development.
  1385 
  1386 * Code generator is now invoked via code_module (incremental code
  1387 generation) and code_library (modular code generation, ML structures
  1388 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1389 must be quoted when used as identifiers.
  1390 
  1391 * New 'value' command for reading, evaluating and printing terms using
  1392 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1393 quoted when used as identifier.
  1394 
  1395 
  1396 *** Locales ***
  1397 
  1398 * New commands for the interpretation of locale expressions in
  1399 theories (1), locales (2) and proof contexts (3).  These generate
  1400 proof obligations from the expression specification.  After the
  1401 obligations have been discharged, theorems of the expression are added
  1402 to the theory, target locale or proof context.  The synopsis of the
  1403 commands is a follows:
  1404 
  1405   (1) interpretation expr inst
  1406   (2) interpretation target < expr
  1407   (3) interpret expr inst
  1408 
  1409 Interpretation in theories and proof contexts require a parameter
  1410 instantiation of terms from the current context.  This is applied to
  1411 specifications and theorems of the interpreted expression.
  1412 Interpretation in locales only permits parameter renaming through the
  1413 locale expression.  Interpretation is smart in that interpretations
  1414 that are active already do not occur in proof obligations, neither are
  1415 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1416 inspect active interpretations of a particular locale.  For details,
  1417 see the Isar Reference manual.  Examples can be found in
  1418 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1419 
  1420 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1421 'interpret' instead.
  1422 
  1423 * New context element 'constrains' for adding type constraints to
  1424 parameters.
  1425 
  1426 * Context expressions: renaming of parameters with syntax
  1427 redeclaration.
  1428 
  1429 * Locale declaration: 'includes' disallowed.
  1430 
  1431 * Proper static binding of attribute syntax -- i.e. types / terms /
  1432 facts mentioned as arguments are always those of the locale definition
  1433 context, independently of the context of later invocations.  Moreover,
  1434 locale operations (renaming and type / term instantiation) are applied
  1435 to attribute arguments as expected.
  1436 
  1437 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1438 actual attributes; rare situations may require Attrib.attribute to
  1439 embed those attributes into Attrib.src that lack concrete syntax.
  1440 Attribute implementations need to cooperate properly with the static
  1441 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1442 Attrib.XXX_thm etc. already do the right thing without further
  1443 intervention.  Only unusual applications -- such as "where" or "of"
  1444 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1445 on the context and the facts involved -- may have to assign parsed
  1446 values to argument tokens explicitly.
  1447 
  1448 * Changed parameter management in theorem generation for long goal
  1449 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1450 theorem statement in rare situations.
  1451 
  1452 * Locale inspection command 'print_locale' omits notes elements.  Use
  1453 'print_locale!' to have them included in the output.
  1454 
  1455 
  1456 *** Provers ***
  1457 
  1458 * Provers/hypsubst.ML: improved version of the subst method, for
  1459 single-step rewriting: it now works in bound variable contexts. New is
  1460 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1461 rewrite a different subterm than the original subst method, which is
  1462 still available as 'simplesubst'.
  1463 
  1464 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1465 and quasi orders.
  1466 
  1467 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1468 reflexive-transitive closure of relations.
  1469 
  1470 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1471 limit (previously hard-coded with a value of 20) user-definable.
  1472 
  1473 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1474 is peformed already.  Object-logics merely need to finish their
  1475 initial simpset configuration as before.  INCOMPATIBILITY.
  1476 
  1477 
  1478 *** HOL ***
  1479 
  1480 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1481 
  1482   syntax (epsilon)
  1483     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1484 
  1485 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1486 and x-symbol; use option '-m epsilon' to get it actually printed.
  1487 Moreover, the mathematically important symbolic identifier \<epsilon>
  1488 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1489 
  1490 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1491 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1492 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1493 support corresponding Isar calculations.
  1494 
  1495 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1496 instead of ":".
  1497 
  1498 * theory SetInterval: changed the syntax for open intervals:
  1499 
  1500   Old       New
  1501   {..n(}    {..<n}
  1502   {)n..}    {n<..}
  1503   {m..n(}   {m..<n}
  1504   {)m..n}   {m<..n}
  1505   {)m..n(}  {m<..<n}
  1506 
  1507 The old syntax is still supported but will disappear in the next
  1508 release.  For conversion use the following Emacs search and replace
  1509 patterns (these are not perfect but work quite well):
  1510 
  1511   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1512   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1513 
  1514 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1515 equalities in commutative rings; method 'algebra' provides a generic
  1516 interface.
  1517 
  1518 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1519 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1520 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1521 be a tuple pattern.
  1522 
  1523 Some new syntax forms are available:
  1524 
  1525   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1526   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1527   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1528   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1529 
  1530 The latter form "\<Sum>x < k. e" used to be based on a separate
  1531 function "Summation", which has been discontinued.
  1532 
  1533 * theory Finite_Set: in structured induction proofs, the insert case
  1534 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1535 (insert F x)'.
  1536 
  1537 * The 'refute' command has been extended to support a much larger
  1538 fragment of HOL, including axiomatic type classes, constdefs and
  1539 typedefs, inductive datatypes and recursion.
  1540 
  1541 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1542 Requires zChaff with proof generation to be installed.  See
  1543 HOL/ex/SAT_Examples.thy for examples.
  1544 
  1545 * Datatype induction via method 'induct' now preserves the name of the
  1546 induction variable. For example, when proving P(xs::'a list) by
  1547 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1548 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1549 in unstructured proof scripts.
  1550 
  1551 * Reworked implementation of records.  Improved scalability for
  1552 records with many fields, avoiding performance problems for type
  1553 inference. Records are no longer composed of nested field types, but
  1554 of nested extension types. Therefore the record type only grows linear
  1555 in the number of extensions and not in the number of fields.  The
  1556 top-level (users) view on records is preserved.  Potential
  1557 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1558 old record representation. The type generated for a record is called
  1559 <record_name>_ext_type.
  1560 
  1561 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1562 proofs triggered by a record definition or a simproc (if
  1563 quick_and_dirty is enabled).  Definitions of large records can take
  1564 quite long.
  1565 
  1566 New simproc record_upd_simproc for simplification of multiple record
  1567 updates enabled by default.  Moreover, trivial updates are also
  1568 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1569 occasionally, since simplification is more powerful by default.
  1570 
  1571 * typedef: proper support for polymorphic sets, which contain extra
  1572 type-variables in the term.
  1573 
  1574 * Simplifier: automatically reasons about transitivity chains
  1575 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1576 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1577 old proofs break occasionally as simplification may now solve more
  1578 goals than previously.
  1579 
  1580 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1581 present.  Works for all partial orders (class "order"), in particular
  1582 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1583 just like y <= x.
  1584 
  1585 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1586 bound variable or a constant then the let is unfolded.  Otherwise
  1587 first a is simplified to b, and then f b is simplified to g. If
  1588 possible we abstract b from g arriving at "let x = b in h x",
  1589 otherwise we unfold the let and arrive at g.  The simproc can be
  1590 enabled/disabled by the reference use_let_simproc.  Potential
  1591 INCOMPATIBILITY since simplification is more powerful by default.
  1592 
  1593 * Classical reasoning: the meson method now accepts theorems as arguments.
  1594 
  1595 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1596 jobs to provide advice on the provability of subgoals.
  1597 
  1598 * Theory OrderedGroup and Ring_and_Field: various additions and
  1599 improvements to faciliate calculations involving equalities and
  1600 inequalities.
  1601 
  1602 The following theorems have been eliminated or modified
  1603 (INCOMPATIBILITY):
  1604 
  1605   abs_eq             now named abs_of_nonneg
  1606   abs_of_ge_0        now named abs_of_nonneg
  1607   abs_minus_eq       now named abs_of_nonpos
  1608   imp_abs_id         now named abs_of_nonneg
  1609   imp_abs_neg_id     now named abs_of_nonpos
  1610   mult_pos           now named mult_pos_pos
  1611   mult_pos_le        now named mult_nonneg_nonneg
  1612   mult_pos_neg_le    now named mult_nonneg_nonpos
  1613   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1614   mult_neg           now named mult_neg_neg
  1615   mult_neg_le        now named mult_nonpos_nonpos
  1616 
  1617 * Theory Parity: added rules for simplifying exponents.
  1618 
  1619 * Theory List:
  1620 
  1621 The following theorems have been eliminated or modified
  1622 (INCOMPATIBILITY):
  1623 
  1624   list_all_Nil       now named list_all.simps(1)
  1625   list_all_Cons      now named list_all.simps(2)
  1626   list_all_conv      now named list_all_iff
  1627   set_mem_eq         now named mem_iff
  1628 
  1629 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1630 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1631 
  1632 
  1633 *** HOL-Complex ***
  1634 
  1635 * Theory RealDef: better support for embedding natural numbers and
  1636 integers in the reals.
  1637 
  1638 The following theorems have been eliminated or modified
  1639 (INCOMPATIBILITY):
  1640 
  1641   exp_ge_add_one_self  now requires no hypotheses
  1642   real_of_int_add      reversed direction of equality (use [symmetric])
  1643   real_of_int_minus    reversed direction of equality (use [symmetric])
  1644   real_of_int_diff     reversed direction of equality (use [symmetric])
  1645   real_of_int_mult     reversed direction of equality (use [symmetric])
  1646 
  1647 * Theory RComplete: expanded support for floor and ceiling functions.
  1648 
  1649 * Theory Ln is new, with properties of the natural logarithm
  1650 
  1651 * Hyperreal: There is a new type constructor "star" for making
  1652 nonstandard types.  The old type names are now type synonyms:
  1653 
  1654   hypreal = real star
  1655   hypnat = nat star
  1656   hcomplex = complex star
  1657 
  1658 * Hyperreal: Many groups of similarly-defined constants have been
  1659 replaced by polymorphic versions (INCOMPATIBILITY):
  1660 
  1661   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1662 
  1663   starset      <-- starsetNat, starsetC
  1664   *s*          <-- *sNat*, *sc*
  1665   starset_n    <-- starsetNat_n, starsetC_n
  1666   *sn*         <-- *sNatn*, *scn*
  1667   InternalSets <-- InternalNatSets, InternalCSets
  1668 
  1669   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1670   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1671   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1672   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1673   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1674 
  1675 * Hyperreal: Many type-specific theorems have been removed in favor of
  1676 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1677 
  1678   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1679   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1680   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1681   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1682   right_minus <-- hypreal_add_minus
  1683   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1684   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1685   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1686   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1687   mult_1_right <-- hcomplex_mult_one_right
  1688   mult_zero_left <-- hcomplex_mult_zero_left
  1689   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1690   right_distrib <-- hypnat_add_mult_distrib2
  1691   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1692   right_inverse <-- hypreal_mult_inverse
  1693   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1694   order_refl <-- {hypreal,hypnat}_le_refl
  1695   order_trans <-- {hypreal,hypnat}_le_trans
  1696   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1697   order_less_le <-- {hypreal,hypnat}_less_le
  1698   linorder_linear <-- {hypreal,hypnat}_le_linear
  1699   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1700   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1701   add_nonneg_nonneg <-- hypreal_le_add_order
  1702 
  1703 * Hyperreal: Separate theorems having to do with type-specific
  1704 versions of constants have been merged into theorems that apply to the
  1705 new polymorphic constants (INCOMPATIBILITY):
  1706 
  1707   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1708   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1709   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1710   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1711   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1712   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1713   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1714   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1715   STAR_diff <-- {STAR,STARC}_diff
  1716   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1717     STARC_hcomplex_of_complex}_image_subset
  1718   starset_n_Un <-- starset{Nat,C}_n_Un
  1719   starset_n_Int <-- starset{Nat,C}_n_Int
  1720   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1721   starset_n_diff <-- starset{Nat,C}_n_diff
  1722   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1723   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1724   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1725   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1726   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1727   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1728   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1729   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1730   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1731   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1732   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1733   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1734   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1735   starfun_diff <-- starfun{C,RC,CR}_diff
  1736   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1737   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1738   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1739   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1740   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1741   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1742   starfun_Id <-- starfunC_Id
  1743   starfun_approx <-- starfun{Nat,CR}_approx
  1744   starfun_capprox <-- starfun{C,RC}_capprox
  1745   starfun_abs <-- starfunNat_rabs
  1746   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1747   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1748   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1749   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1750   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1751   starfun_add_approx <-- starfunCR_add_approx
  1752   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1753   starfun_divide <-- starfun{C,CR,RC}_divide
  1754   starfun_n <-- starfun{Nat,C}_n
  1755   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1756   starfun_n_add <-- starfun{Nat,C}_n_add
  1757   starfun_n_add_minus <-- starfunNat_n_add_minus
  1758   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1759   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1760   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1761 
  1762   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1763   star_n_minus <-- {hypreal,hcomplex}_minus
  1764   star_n_diff <-- {hypreal,hcomplex}_diff
  1765   star_n_mult <-- {hypreal,hcomplex}_mult
  1766   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1767   star_n_le <-- {hypreal,hypnat}_le
  1768   star_n_less <-- {hypreal,hypnat}_less
  1769   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1770   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1771   star_n_abs <-- hypreal_hrabs
  1772   star_n_divide <-- hcomplex_divide
  1773 
  1774   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1775   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1776   star_of_diff <-- hypreal_of_real_diff
  1777   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1778   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1779   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1780   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1781   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1782   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1783   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1784   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1785   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1786   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1787   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1788   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1789   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1790   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1791   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1792   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1793   star_of_power <-- hypreal_of_real_power
  1794   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1795 
  1796 * Hyperreal: new method "transfer" that implements the transfer
  1797 principle of nonstandard analysis. With a subgoal that mentions
  1798 nonstandard types like "'a star", the command "apply transfer"
  1799 replaces it with an equivalent one that mentions only standard types.
  1800 To be successful, all free variables must have standard types; non-
  1801 standard variables must have explicit universal quantifiers.
  1802 
  1803 * Hyperreal: A theory of Taylor series.
  1804 
  1805 
  1806 *** HOLCF ***
  1807 
  1808 * Discontinued special version of 'constdefs' (which used to support
  1809 continuous functions) in favor of the general Pure one with full
  1810 type-inference.
  1811 
  1812 * New simplification procedure for solving continuity conditions; it
  1813 is much faster on terms with many nested lambda abstractions (cubic
  1814 instead of exponential time).
  1815 
  1816 * New syntax for domain package: selector names are now optional.
  1817 Parentheses should be omitted unless argument is lazy, for example:
  1818 
  1819   domain 'a stream = cons "'a" (lazy "'a stream")
  1820 
  1821 * New command 'fixrec' for defining recursive functions with pattern
  1822 matching; defining multiple functions with mutual recursion is also
  1823 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1824 sinr, or any data constructor defined by the domain package. The given
  1825 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1826 syntax and examples.
  1827 
  1828 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1829 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1830 but the proof obligation additionally includes an admissibility
  1831 requirement. The packages generate instances of class cpo or pcpo,
  1832 with continuity and strictness theorems for Rep and Abs.
  1833 
  1834 * HOLCF: Many theorems have been renamed according to a more standard naming
  1835 scheme (INCOMPATIBILITY):
  1836 
  1837   foo_inject:  "foo$x = foo$y ==> x = y"
  1838   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1839   foo_less:    "(foo$x << foo$y) = (x << y)"
  1840   foo_strict:  "foo$UU = UU"
  1841   foo_defined: "... ==> foo$x ~= UU"
  1842   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1843 
  1844 
  1845 *** ZF ***
  1846 
  1847 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1848 including the First Isomorphism Theorem (on quotienting by the kernel
  1849 of a homomorphism).
  1850 
  1851 * ZF/Simplifier: install second copy of type solver that actually
  1852 makes use of TC rules declared to Isar proof contexts (or locales);
  1853 the old version is still required for ML proof scripts.
  1854 
  1855 
  1856 *** Cube ***
  1857 
  1858 * Converted to Isar theory format; use locales instead of axiomatic
  1859 theories.
  1860 
  1861 
  1862 *** ML ***
  1863 
  1864 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1865 for ||>, ||>>, |>>,
  1866 
  1867 * Pure/library.ML no longer defines its own option datatype, but uses
  1868 that of the SML basis, which has constructors NONE and SOME instead of
  1869 None and Some, as well as exception Option.Option instead of OPTION.
  1870 The functions the, if_none, is_some, is_none have been adapted
  1871 accordingly, while Option.map replaces apsome.
  1872 
  1873 * Pure/library.ML: the exception LIST has been given up in favour of
  1874 the standard exceptions Empty and Subscript, as well as
  1875 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1876 superceded by the standard hd and tl functions etc.
  1877 
  1878 A number of basic list functions are no longer exported to the ML
  1879 toplevel, as they are variants of predefined functions.  The following
  1880 suggests how one can translate existing code:
  1881 
  1882     rev_append xs ys = List.revAppend (xs, ys)
  1883     nth_elem (i, xs) = List.nth (xs, i)
  1884     last_elem xs = List.last xs
  1885     flat xss = List.concat xss
  1886     seq fs = List.app fs
  1887     partition P xs = List.partition P xs
  1888     mapfilter f xs = List.mapPartial f xs
  1889 
  1890 * Pure/library.ML: several combinators for linear functional
  1891 transformations, notably reverse application and composition:
  1892 
  1893   x |> f                f #> g
  1894   (x, y) |-> f          f #-> g
  1895 
  1896 * Pure/library.ML: introduced/changed precedence of infix operators:
  1897 
  1898   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1899   infix 2 ?;
  1900   infix 3 o oo ooo oooo;
  1901   infix 4 ~~ upto downto;
  1902 
  1903 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1904 infix operators.
  1905 
  1906 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1907 fold_map support linear functional transformations and nesting.  For
  1908 example:
  1909 
  1910   fold f [x1, ..., xN] y =
  1911     y |> f x1 |> ... |> f xN
  1912 
  1913   (fold o fold) f [xs1, ..., xsN] y =
  1914     y |> fold f xs1 |> ... |> fold f xsN
  1915 
  1916   fold f [x1, ..., xN] =
  1917     f x1 #> ... #> f xN
  1918 
  1919   (fold o fold) f [xs1, ..., xsN] =
  1920     fold f xs1 #> ... #> fold f xsN
  1921 
  1922 * Pure/library.ML: the following selectors on type 'a option are
  1923 available:
  1924 
  1925   the:               'a option -> 'a  (*partial*)
  1926   these:             'a option -> 'a  where 'a = 'b list
  1927   the_default: 'a -> 'a option -> 'a
  1928   the_list:          'a option -> 'a list
  1929 
  1930 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1931 basic operations for association lists, following natural argument
  1932 order; moreover the explicit equality predicate passed here avoids
  1933 potentially expensive polymorphic runtime equality checks.
  1934 The old functions may be expressed as follows:
  1935 
  1936   assoc = uncurry (AList.lookup (op =))
  1937   assocs = these oo AList.lookup (op =)
  1938   overwrite = uncurry (AList.update (op =)) o swap
  1939 
  1940 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1941 
  1942   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1943   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1944 
  1945 replacing make_keylist and keyfilter (occassionally used)
  1946 Naive rewrites:
  1947 
  1948   make_keylist = AList.make
  1949   keyfilter = AList.find (op =)
  1950 
  1951 * eq_fst and eq_snd now take explicit equality parameter, thus
  1952   avoiding eqtypes. Naive rewrites:
  1953 
  1954     eq_fst = eq_fst (op =)
  1955     eq_snd = eq_snd (op =)
  1956 
  1957 * Removed deprecated apl and apr (rarely used).
  1958   Naive rewrites:
  1959 
  1960     apl (n, op) =>>= curry op n
  1961     apr (op, m) =>>= fn n => op (n, m)
  1962 
  1963 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1964 provides a reasonably efficient light-weight implementation of sets as
  1965 lists.
  1966 
  1967 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1968 few new operations; existing lookup and update are now curried to
  1969 follow natural argument order (for use with fold etc.);
  1970 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1971 
  1972 * Pure/General: output via the Isabelle channels of
  1973 writeln/warning/error etc. is now passed through Output.output, with a
  1974 hook for arbitrary transformations depending on the print_mode
  1975 (cf. Output.add_mode -- the first active mode that provides a output
  1976 function wins).  Already formatted output may be embedded into further
  1977 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1978 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1979 accommodate easy composition of diagnostic messages etc.  Programmers
  1980 rarely need to care about Output.output or Output.raw at all, with
  1981 some notable exceptions: Output.output is required when bypassing the
  1982 standard channels (writeln etc.), or in token translations to produce
  1983 properly formatted results; Output.raw is required when capturing
  1984 already output material that will eventually be presented to the user
  1985 a second time.  For the default print mode, both Output.output and
  1986 Output.raw have no effect.
  1987 
  1988 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1989 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1990 cumulative results are displayed at the end of a batch session.
  1991 
  1992 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1993 replaced by File.platform_path and File.shell_path (with appropriate
  1994 hooks).  This provides a clean interface for unusual systems where the
  1995 internal and external process view of file names are different.
  1996 
  1997 * Pure: more efficient orders for basic syntactic entities: added
  1998 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1999 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2000 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2001 orders now -- potential INCOMPATIBILITY for code that depends on a
  2002 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2003 Library.sort_strings on result).
  2004 
  2005 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2006 fold_types traverse types/terms from left to right, observing natural
  2007 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2008 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2009 
  2010 * Pure: name spaces have been refined, with significant changes of the
  2011 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2012 to extern(_table).  The plain name entry path is superceded by a
  2013 general 'naming' context, which also includes the 'policy' to produce
  2014 a fully qualified name and external accesses of a fully qualified
  2015 name; NameSpace.extend is superceded by context dependent
  2016 Sign.declare_name.  Several theory and proof context operations modify
  2017 the naming context.  Especially note Theory.restore_naming and
  2018 ProofContext.restore_naming to get back to a sane state; note that
  2019 Theory.add_path is no longer sufficient to recover from
  2020 Theory.absolute_path in particular.
  2021 
  2022 * Pure: new flags short_names (default false) and unique_names
  2023 (default true) for controlling output of qualified names.  If
  2024 short_names is set, names are printed unqualified.  If unique_names is
  2025 reset, the name prefix is reduced to the minimum required to achieve
  2026 the original result when interning again, even if there is an overlap
  2027 with earlier declarations.
  2028 
  2029 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2030 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2031 (useful for printing error messages).  INCOMPATIBILITY.
  2032 
  2033 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2034 Theory.theory are now identified, referring to the universal
  2035 Context.theory (see Pure/context.ML).  Actual signature and theory
  2036 content is managed as theory data.  The old code and interfaces were
  2037 spread over many files and structures; the new arrangement introduces
  2038 considerable INCOMPATIBILITY to gain more clarity:
  2039 
  2040   Context -- theory management operations (name, identity, inclusion,
  2041     parents, ancestors, merge, etc.), plus generic theory data;
  2042 
  2043   Sign -- logical signature and syntax operations (declaring consts,
  2044     types, etc.), plus certify/read for common entities;
  2045 
  2046   Theory -- logical theory operations (stating axioms, definitions,
  2047     oracles), plus a copy of logical signature operations (consts,
  2048     types, etc.); also a few basic management operations (Theory.copy,
  2049     Theory.merge, etc.)
  2050 
  2051 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2052 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2053 for convenience -- they merely return the theory.
  2054 
  2055 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2056 
  2057 * Pure: the Isar proof context type is already defined early in Pure
  2058 as Context.proof (note that ProofContext.context and Proof.context are
  2059 aliases, where the latter is the preferred name).  This enables other
  2060 Isabelle components to refer to that type even before Isar is present.
  2061 
  2062 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2063 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2064 any of these kinds.  For example, Sign.intern typeK is now
  2065 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2066 Theory.hide_types.  Also note that former
  2067 Theory.hide_classes/types/consts are now
  2068 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2069 internalize their arguments!  INCOMPATIBILITY.
  2070 
  2071 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2072 datatype thmref (with constructors Name and NameSelection) instead of
  2073 plain string -- INCOMPATIBILITY;
  2074 
  2075 * Pure: cases produced by proof methods specify options, where NONE
  2076 means to remove case bindings -- INCOMPATIBILITY in
  2077 (RAW_)METHOD_CASES.
  2078 
  2079 * Pure: the following operations retrieve axioms or theorems from a
  2080 theory node or theory hierarchy, respectively:
  2081 
  2082   Theory.axioms_of: theory -> (string * term) list
  2083   Theory.all_axioms_of: theory -> (string * term) list
  2084   PureThy.thms_of: theory -> (string * thm) list
  2085   PureThy.all_thms_of: theory -> (string * thm) list
  2086 
  2087 * Pure: print_tac now outputs the goal through the trace channel.
  2088 
  2089 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2090 Reference Toplevel.debug (default false) controls detailed printing
  2091 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2092 controls execution profiling -- set to 1 for time and 2 for space
  2093 (both increase the runtime).
  2094 
  2095 * Isar session: The initial use of ROOT.ML is now always timed,
  2096 i.e. the log will show the actual process times, in contrast to the
  2097 elapsed wall-clock time that the outer shell wrapper produces.
  2098 
  2099 * Simplifier: improved handling of bound variables (nameless
  2100 representation, avoid allocating new strings).  Simprocs that invoke
  2101 the Simplifier recursively should use Simplifier.inherit_bounds to
  2102 avoid local name clashes.  Failure to do so produces warnings
  2103 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2104 for further details.
  2105 
  2106 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2107 bindings for all theorems stored within a given theory; this may help
  2108 in porting non-Isar theories to Isar ones, while keeping ML proof
  2109 scripts for the time being.
  2110 
  2111 * ML operator HTML.with_charset specifies the charset begin used for
  2112 generated HTML files.  For example:
  2113 
  2114   HTML.with_charset "utf-8" use_thy "Hebrew";
  2115   HTML.with_charset "utf-8" use_thy "Chinese";
  2116 
  2117 
  2118 *** System ***
  2119 
  2120 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2121 isabelle, isatool etc.).
  2122 
  2123 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2124 isatool doc, isatool mkdir, display_drafts etc.).
  2125 
  2126 * isatool usedir: option -f allows specification of the ML file to be
  2127 used by Isabelle; default is ROOT.ML.
  2128 
  2129 * New isatool version outputs the version identifier of the Isabelle
  2130 distribution being used.
  2131 
  2132 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2133 (containing Boolean satisfiability problems) into Isabelle/HOL
  2134 theories.
  2135 
  2136 
  2137 
  2138 New in Isabelle2004 (April 2004)
  2139 --------------------------------
  2140 
  2141 *** General ***
  2142 
  2143 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2144   Replaces linorder.ML.
  2145 
  2146 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2147   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2148   (\<a>...\<z>), are now considered normal letters, and can therefore
  2149   be used anywhere where an ASCII letter (a...zA...Z) has until
  2150   now. COMPATIBILITY: This obviously changes the parsing of some
  2151   terms, especially where a symbol has been used as a binder, say
  2152   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2153   as an identifier.  Fix it by inserting a space around former
  2154   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2155   existing theory and ML files.
  2156 
  2157 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2158 
  2159 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2160   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2161   a normal (but invisible) letter. For multiple letter subscripts repeat
  2162   \<^isub> like this: x\<^isub>1\<^isub>2.
  2163 
  2164 * Pure: There are now sub-/superscripts that can span more than one
  2165   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2166   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2167   superscript. The new control characters are not identifier parts.
  2168 
  2169 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2170   content of "..." to the latex file instead of \isacntrl... . The "..."
  2171   may consist of any printable characters excluding the end bracket >.
  2172 
  2173 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2174   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2175   declare constants "final", which prevents their being given a definition
  2176   later.  It is useful for constants whose behaviour is fixed axiomatically
  2177   rather than definitionally, such as the meta-logic connectives.
  2178 
  2179 * Pure: 'instance' now handles general arities with general sorts
  2180   (i.e. intersections of classes),
  2181 
  2182 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2183   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2184   It can be changed to alter the colors/layout of generated pages.
  2185 
  2186 
  2187 *** Isar ***
  2188 
  2189 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2190   cut_tac, subgoal_tac and thin_tac:
  2191   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2192     locales are no longer forced to write Isar proof scripts.
  2193     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2194     emulations.
  2195   - INCOMPATIBILITY: names of variables to be instantiated may no
  2196     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2197     This is consistent with the instantiation attribute "where".
  2198 
  2199 * Attributes "where" and "of":
  2200   - Now take type variables of instantiated theorem into account when reading
  2201     the instantiation string.  This fixes a bug that caused instantiated
  2202     theorems to have too special types in some circumstances.
  2203   - "where" permits explicit instantiations of type variables.
  2204 
  2205 * Calculation commands "moreover" and "also" no longer interfere with
  2206   current facts ("this"), admitting arbitrary combinations with "then"
  2207   and derived forms.
  2208 
  2209 * Locales:
  2210   - Goal statements involving the context element "includes" no longer
  2211     generate theorems with internal delta predicates (those ending on
  2212     "_axioms") in the premise.
  2213     Resolve particular premise with <locale>.intro to obtain old form.
  2214   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2215     specification and "includes" elements in goal statement.
  2216   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2217     [intro?] and [elim?] (respectively) by default.
  2218   - Experimental command for instantiation of locales in proof contexts:
  2219         instantiate <label>[<attrs>]: <loc>
  2220     Instantiates locale <loc> and adds all its theorems to the current context
  2221     taking into account their attributes.  Label and attrs are optional
  2222     modifiers, like in theorem declarations.  If present, names of
  2223     instantiated theorems are qualified with <label>, and the attributes
  2224     <attrs> are applied after any attributes these theorems might have already.
  2225       If the locale has assumptions, a chained fact of the form
  2226     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2227     are derived.  The command does not support old-style locales declared
  2228     with "locale (open)".
  2229       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2230 
  2231 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2232   (Isar) contexts.
  2233 
  2234 
  2235 *** HOL ***
  2236 
  2237 * Proof import: new image HOL4 contains the imported library from
  2238   the HOL4 system with about 2500 theorems. It is imported by
  2239   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2240   can be used like any other Isabelle image.  See
  2241   HOL/Import/HOL/README for more information.
  2242 
  2243 * Simplifier:
  2244   - Much improved handling of linear and partial orders.
  2245     Reasoners for linear and partial orders are set up for type classes
  2246     "linorder" and "order" respectively, and are added to the default simpset
  2247     as solvers.  This means that the simplifier can build transitivity chains
  2248     to solve goals from the assumptions.
  2249   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2250     of blast or auto after simplification become unnecessary because the goal
  2251     is solved by simplification already.
  2252 
  2253 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2254     all proved in axiomatic type classes for semirings, rings and fields.
  2255 
  2256 * Numerics:
  2257   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2258     now formalized using the Ring_and_Field theory mentioned above.
  2259   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2260     than before, because now they are set up once in a generic manner.
  2261   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2262     Look for the general versions in Ring_and_Field (and Power if they concern
  2263     exponentiation).
  2264 
  2265 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2266 
  2267 * Records:
  2268   - Record types are now by default printed with their type abbreviation
  2269     instead of the list of all field types. This can be configured via
  2270     the reference "print_record_type_abbr".
  2271   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2272     (not enabled by default).
  2273   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2274     EX x. x = sel r to True (not enabled by default).
  2275   - Tactic "record_split_simp_tac" to split and simplify records added.
  2276 
  2277 * 'specification' command added, allowing for definition by
  2278   specification.  There is also an 'ax_specification' command that
  2279   introduces the new constants axiomatically.
  2280 
  2281 * arith(_tac) is now able to generate counterexamples for reals as well.
  2282 
  2283 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2284 
  2285 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2286   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2287 
  2288 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2289   matrix theory to linear programming.
  2290 
  2291 * Unions and Intersections:
  2292   The latex output syntax of UN and INT has been changed
  2293   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2294   i.e. the index formulae has become a subscript.
  2295   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2296 
  2297 * Unions and Intersections over Intervals:
  2298   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2299   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2300   like in normal math, and corresponding versions for < and for intersection.
  2301 
  2302 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2303   lexicographic dictonary ordering has been added as "lexord".
  2304 
  2305 * ML: the legacy theory structures Int and List have been removed. They had
  2306   conflicted with ML Basis Library structures having the same names.
  2307 
  2308 * 'refute' command added to search for (finite) countermodels.  Only works
  2309   for a fragment of HOL.  The installation of an external SAT solver is
  2310   highly recommended.  See "HOL/Refute.thy" for details.
  2311 
  2312 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2313   formulae under an assignment of free variables to random values.
  2314   In contrast to 'refute', it can deal with inductive datatypes,
  2315   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2316   for examples.
  2317 
  2318 
  2319 *** HOLCF ***
  2320 
  2321 * Streams now come with concatenation and are part of the HOLCF image
  2322 
  2323 
  2324 
  2325 New in Isabelle2003 (May 2003)
  2326 ------------------------------
  2327 
  2328 *** General ***
  2329 
  2330 * Provers/simplifier:
  2331 
  2332   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2333     Assumptions are now subject to complete mutual simplification,
  2334     not just from left to right. The simplifier now preserves
  2335     the order of assumptions.
  2336 
  2337     Potential INCOMPATIBILITY:
  2338 
  2339     -- simp sometimes diverges where the old version did
  2340        not, e.g. invoking simp on the goal
  2341 
  2342         [| P (f x); y = x; f x = f y |] ==> Q
  2343 
  2344        now gives rise to the infinite reduction sequence
  2345 
  2346         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2347 
  2348        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2349        kind of problem.
  2350 
  2351     -- Tactics combining classical reasoner and simplification (such as auto)
  2352        are also affected by this change, because many of them rely on
  2353        simp. They may sometimes diverge as well or yield a different numbers
  2354        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2355        in case of problems. Sometimes subsequent calls to the classical
  2356        reasoner will fail because a preceeding call to the simplifier too
  2357        eagerly simplified the goal, e.g. deleted redundant premises.
  2358 
  2359   - The simplifier trace now shows the names of the applied rewrite rules
  2360 
  2361   - You can limit the number of recursive invocations of the simplifier
  2362     during conditional rewriting (where the simplifie tries to solve the
  2363     conditions before applying the rewrite rule):
  2364     ML "simp_depth_limit := n"
  2365     where n is an integer. Thus you can force termination where previously
  2366     the simplifier would diverge.
  2367 
  2368   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2369 
  2370   - No longer aborts on failed congruence proof.  Instead, the
  2371     congruence is ignored.
  2372 
  2373 * Pure: New generic framework for extracting programs from constructive
  2374   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2375   as HOL/Extraction for some case studies.
  2376 
  2377 * Pure: The main goal of the proof state is no longer shown by default, only
  2378 the subgoals. This behaviour is controlled by a new flag.
  2379    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2380 (ML: Proof.show_main_goal).
  2381 
  2382 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2383 rules whose conclusion matches subgoal 1:
  2384       PG menu: Isabelle/Isar -> Show me -> matching rules
  2385 The rules are ordered by how closely they match the subgoal.
  2386 In particular, rules that solve a subgoal outright are displayed first
  2387 (or rather last, the way they are printed).
  2388 (ML: ProofGeneral.print_intros())
  2389 
  2390 * Pure: New flag trace_unify_fail causes unification to print
  2391 diagnostic information (PG: in trace buffer) when it fails. This is
  2392 useful for figuring out why single step proofs like rule, erule or
  2393 assumption failed.
  2394 
  2395 * Pure: Locale specifications now produce predicate definitions
  2396 according to the body of text (covering assumptions modulo local
  2397 definitions); predicate "loc_axioms" covers newly introduced text,
  2398 while "loc" is cumulative wrt. all included locale expressions; the
  2399 latter view is presented only on export into the global theory
  2400 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2401 on the old view without predicates;
  2402 
  2403 * Pure: predefined locales "var" and "struct" are useful for sharing
  2404 parameters (as in CASL, for example); just specify something like
  2405 ``var x + var y + struct M'' as import;
  2406 
  2407 * Pure: improved thms_containing: proper indexing of facts instead of
  2408 raw theorems; check validity of results wrt. current name space;
  2409 include local facts of proof configuration (also covers active
  2410 locales), cover fixed variables in index; may use "_" in term
  2411 specification; an optional limit for the number of printed facts may
  2412 be given (the default is 40);
  2413 
  2414 * Pure: disallow duplicate fact bindings within new-style theory files
  2415 (batch-mode only);
  2416 
  2417 * Provers: improved induct method: assumptions introduced by case
  2418 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2419 the goal statement); "foo" still refers to all facts collectively;
  2420 
  2421 * Provers: the function blast.overloaded has been removed: all constants
  2422 are regarded as potentially overloaded, which improves robustness in exchange
  2423 for slight decrease in efficiency;
  2424 
  2425 * Provers/linorder: New generic prover for transitivity reasoning over
  2426 linear orders.  Note: this prover is not efficient!
  2427 
  2428 * Isar: preview of problems to finish 'show' now produce an error
  2429 rather than just a warning (in interactive mode);
  2430 
  2431 
  2432 *** HOL ***
  2433 
  2434 * arith(_tac)
  2435 
  2436  - Produces a counter example if it cannot prove a goal.
  2437    Note that the counter example may be spurious if the goal is not a formula
  2438    of quantifier-free linear arithmetic.
  2439    In ProofGeneral the counter example appears in the trace buffer.
  2440 
  2441  - Knows about div k and mod k where k is a numeral of type nat or int.
  2442 
  2443  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2444    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2445    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2446 
  2447 * simp's arithmetic capabilities have been enhanced a bit: it now
  2448 takes ~= in premises into account (by performing a case split);
  2449 
  2450 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2451 are distributed over a sum of terms;
  2452 
  2453 * New tactic "trans_tac" and method "trans" instantiate
  2454 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2455 "<=", "<" and "=").
  2456 
  2457 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2458 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2459 
  2460 * 'typedef' command has new option "open" to suppress the set
  2461 definition;
  2462 
  2463 * functions Min and Max on finite sets have been introduced (theory
  2464 Finite_Set);
  2465 
  2466 * attribute [symmetric] now works for relations as well; it turns
  2467 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2468 
  2469 * induct over a !!-quantified statement (say !!x1..xn):
  2470   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2471 
  2472 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2473 %x. None. Warning: empty_def now refers to the previously hidden definition
  2474 of the empty set.
  2475 
  2476 * Algebra: formalization of classical algebra.  Intended as base for
  2477 any algebraic development in Isabelle.  Currently covers group theory
  2478 (up to Sylow's theorem) and ring theory (Universal Property of
  2479 Univariate Polynomials).  Contributions welcome;
  2480 
  2481 * GroupTheory: deleted, since its material has been moved to Algebra;
  2482 
  2483 * Complex: new directory of the complex numbers with numeric constants,
  2484 nonstandard complex numbers, and some complex analysis, standard and
  2485 nonstandard (Jacques Fleuriot);
  2486 
  2487 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2488 
  2489 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2490 Fleuriot);
  2491 
  2492 * Real/HahnBanach: updated and adapted to locales;
  2493 
  2494 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2495 Gray and Kramer);
  2496 
  2497 * UNITY: added the Meier-Sanders theory of progress sets;
  2498 
  2499 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2500 as abstract algorithms, instantiated to the JVM;
  2501 
  2502 * Bali: Java source language formalization. Type system, operational
  2503 semantics, axiomatic semantics. Supported language features:
  2504 classes, interfaces, objects,virtual methods, static methods,
  2505 static/instance fields, arrays, access modifiers, definite
  2506 assignment, exceptions.
  2507 
  2508 
  2509 *** ZF ***
  2510 
  2511 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2512 universe, etc.);
  2513 
  2514 * Main ZF: virtually all theories converted to new-style format;
  2515 
  2516 
  2517 *** ML ***
  2518 
  2519 * Pure: Tactic.prove provides sane interface for internal proofs;
  2520 omits the infamous "standard" operation, so this is more appropriate
  2521 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2522 
  2523 * Pure: improved error reporting of simprocs;
  2524 
  2525 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2526 up simprocs;
  2527 
  2528 
  2529 *** Document preparation ***
  2530 
  2531 * uses \par instead of \\ for line breaks in theory text. This may
  2532 shift some page breaks in large documents. To get the old behaviour
  2533 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2534 
  2535 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2536 other packages
  2537 
  2538 * \<euro> now needs package babel/greek instead of marvosym (which
  2539 broke \Rightarrow)
  2540 
  2541 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2542 textcomp package)
  2543 
  2544 
  2545 
  2546 New in Isabelle2002 (March 2002)
  2547 --------------------------------
  2548 
  2549 *** Document preparation ***
  2550 
  2551 * greatly simplified document preparation setup, including more
  2552 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2553 instructive isatool mkdir; users should basically be able to get
  2554 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2555 users may run a separate document processing stage manually like this:
  2556 "isatool usedir -D output HOL Test && isatool document Test/output";
  2557 
  2558 * theory dependency graph may now be incorporated into documents;
  2559 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2560 with \includegraphics of LaTeX;
  2561 
  2562 * proper spacing of consecutive markup elements, especially text
  2563 blocks after section headings;
  2564 
  2565 * support bold style (for single symbols only), input syntax is like
  2566 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2567 
  2568 * \<bullet> is now output as bold \cdot by default, which looks much
  2569 better in printed text;
  2570 
  2571 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2572 note that these symbols are currently unavailable in Proof General /
  2573 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2574 
  2575 * isatool latex no longer depends on changed TEXINPUTS, instead
  2576 isatool document copies the Isabelle style files to the target
  2577 location;
  2578 
  2579 
  2580 *** Isar ***
  2581 
  2582 * Pure/Provers: improved proof by cases and induction;
  2583   - 'case' command admits impromptu naming of parameters (such as
  2584     "case (Suc n)");
  2585   - 'induct' method divinates rule instantiation from the inductive
  2586     claim; no longer requires excessive ?P bindings for proper
  2587     instantiation of cases;
  2588   - 'induct' method properly enumerates all possibilities of set/type
  2589     rules; as a consequence facts may be also passed through *type*
  2590     rules without further ado;
  2591   - 'induct' method now derives symbolic cases from the *rulified*
  2592     rule (before it used to rulify cases stemming from the internal
  2593     atomized version); this means that the context of a non-atomic
  2594     statement becomes is included in the hypothesis, avoiding the
  2595     slightly cumbersome show "PROP ?case" form;
  2596   - 'induct' may now use elim-style induction rules without chaining
  2597     facts, using ``missing'' premises from the goal state; this allows
  2598     rules stemming from inductive sets to be applied in unstructured
  2599     scripts, while still benefitting from proper handling of non-atomic
  2600     statements; NB: major inductive premises need to be put first, all
  2601     the rest of the goal is passed through the induction;
  2602   - 'induct' proper support for mutual induction involving non-atomic
  2603     rule statements (uses the new concept of simultaneous goals, see
  2604     below);
  2605   - append all possible rule selections, but only use the first
  2606     success (no backtracking);
  2607   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2608   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2609   - added 'print_induct_rules' (covered by help item in recent Proof
  2610     General versions);
  2611   - moved induct/cases attributes to Pure, methods to Provers;
  2612   - generic method setup instantiated for FOL and HOL;
  2613 
  2614 * Pure: support multiple simultaneous goal statements, for example
  2615 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2616 meta-level mechanism, this acts as if several individual goals had
  2617 been stated separately; in particular common proof methods need to be
  2618 repeated in order to cover all claims; note that a single elimination
  2619 step is *not* sufficient to establish the two conjunctions, so this
  2620 fails:
  2621 
  2622   assume "A & B" then have A and B ..   (*".." fails*)
  2623 
  2624 better use "obtain" in situations as above; alternative refer to
  2625 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2626 
  2627 * Pure: proper integration with ``locales''; unlike the original
  2628 version by Florian Kammller, Isar locales package high-level proof
  2629 contexts rather than raw logical ones (e.g. we admit to include
  2630 attributes everywhere); operations on locales include merge and
  2631 rename; support for implicit arguments (``structures''); simultaneous
  2632 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2633 some examples;
  2634 
  2635 * Pure: the following commands have been ``localized'', supporting a
  2636 target locale specification "(in name)": 'lemma', 'theorem',
  2637 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2638 stored both within the locale and at the theory level (exported and
  2639 qualified by the locale name);
  2640 
  2641 * Pure: theory goals may now be specified in ``long'' form, with
  2642 ad-hoc contexts consisting of arbitrary locale elements. for example
  2643 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2644 definitions may be given, too); the result is a meta-level rule with
  2645 the context elements being discharged in the obvious way;
  2646 
  2647 * Pure: new proof command 'using' allows to augment currently used
  2648 facts after a goal statement ('using' is syntactically analogous to
  2649 'apply', but acts on the goal's facts only); this allows chained facts
  2650 to be separated into parts given before and after a claim, as in
  2651 ``from a and b have C using d and e <proof>'';
  2652 
  2653 * Pure: renamed "antecedent" case to "rule_context";
  2654 
  2655 * Pure: new 'judgment' command records explicit information about the
  2656 object-logic embedding (used by several tools internally); no longer
  2657 use hard-wired "Trueprop";
  2658 
  2659 * Pure: added 'corollary' command;
  2660 
  2661 * Pure: fixed 'token_translation' command;
  2662 
  2663 * Pure: removed obsolete 'exported' attribute;
  2664 
  2665 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2666 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2667 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2668 
  2669 * Pure: method 'atomize' presents local goal premises as object-level
  2670 statements (atomic meta-level propositions); setup controlled via
  2671 rewrite rules declarations of 'atomize' attribute; example
  2672 application: 'induct' method with proper rule statements in improper
  2673 proof *scripts*;
  2674 
  2675 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2676 now consider the syntactic context of assumptions, giving a better
  2677 chance to get type-inference of the arguments right (this is
  2678 especially important for locales);
  2679 
  2680 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2681 mode;
  2682 
  2683 * Pure/obtain: the formal conclusion "thesis", being marked as
  2684 ``internal'', may no longer be reference directly in the text;
  2685 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2686 situations;
  2687 
  2688 * Pure: generic 'sym' attribute which declares a rule both as pure
  2689 'elim?' and for the 'symmetric' operation;
  2690 
  2691 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2692 text; the fixed correlation with particular command syntax has been
  2693 discontinued;
  2694 
  2695 * Pure: new method 'rules' is particularly well-suited for proof
  2696 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2697 but often produces more compact proof terms with less detours;
  2698 
  2699 * Pure/Provers/classical: simplified integration with pure rule
  2700 attributes and methods; the classical "intro?/elim?/dest?"
  2701 declarations coincide with the pure ones; the "rule" method no longer
  2702 includes classically swapped intros; "intro" and "elim" methods no
  2703 longer pick rules from the context; also got rid of ML declarations
  2704 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2705 INCOMPATIBILITY;
  2706 
  2707 * Provers/classical: attribute 'swapped' produces classical inversions
  2708 of introduction rules;
  2709 
  2710 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2711 rules instead of full simplifier context; 'iff' attribute handles
  2712 conditional rules;
  2713 
  2714 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2715 
  2716 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2717 "(permissive)" option to recover old behavior;
  2718 
  2719 * HOL: 'inductive' no longer features separate (collective) attributes
  2720 for 'intros' (was found too confusing);
  2721 
  2722 * HOL: properly declared induction rules less_induct and
  2723 wf_induct_rule;
  2724 
  2725 
  2726 *** HOL ***
  2727 
  2728 * HOL: moved over to sane numeral syntax; the new policy is as
  2729 follows:
  2730 
  2731   - 0 and 1 are polymorphic constants, which are defined on any
  2732   numeric type (nat, int, real etc.);
  2733 
  2734   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2735   binary representation internally;
  2736 
  2737   - type nat has special constructor Suc, and generally prefers Suc 0
  2738   over 1::nat and Suc (Suc 0) over 2::nat;
  2739 
  2740 This change may cause significant problems of INCOMPATIBILITY; here
  2741 are some hints on converting existing sources:
  2742 
  2743   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2744   entities, so expressions involving "-" (unary or binary minus) need
  2745   to be spaced properly;
  2746 
  2747   - existing occurrences of "1" may need to be constraint "1::nat" or
  2748   even replaced by Suc 0; similar for old "2";
  2749 
  2750   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2751 
  2752   - remove all special provisions on numerals in proofs;
  2753 
  2754 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2755 representation (depends on bin_arith_simps in the default context);
  2756 
  2757 * HOL: symbolic syntax for x^2 (numeral 2);
  2758 
  2759 * HOL: the class of all HOL types is now called "type" rather than
  2760 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2761 in axclass/classes, instance/arities, and (usually rare) occurrences
  2762 in typings (of consts etc.); internally the class is called
  2763 "HOL.type", ML programs should refer to HOLogic.typeS;
  2764 
  2765 * HOL/record package improvements:
  2766   - new derived operations "fields" to build a partial record section,
  2767     "extend" to promote a fixed record to a record scheme, and
  2768     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2769     declared as simp by default;
  2770   - shared operations ("more", "fields", etc.) now need to be always
  2771     qualified) --- potential INCOMPATIBILITY;
  2772   - removed "make_scheme" operations (use "make" with "extend") --
  2773     INCOMPATIBILITY;
  2774   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2775   - provides cases/induct rules for use with corresponding Isar
  2776     methods (for concrete records, record schemes, concrete more
  2777     parts, and schematic more parts -- in that order);
  2778   - internal definitions directly based on a light-weight abstract
  2779     theory of product types over typedef rather than datatype;
  2780 
  2781 * HOL: generic code generator for generating executable ML code from
  2782 specifications; specific support for HOL constructs such as inductive
  2783 datatypes and sets, as well as recursive functions; can be invoked
  2784 via 'generate_code' theory section;
  2785 
  2786 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2787 
  2788 * HOL: consolidated and renamed several theories.  In particular:
  2789         Ord.thy has been absorbed into HOL.thy
  2790         String.thy has been absorbed into List.thy
  2791 
  2792 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2793 (beware of argument permutation!);
  2794 
  2795 * HOL: linorder_less_split superseded by linorder_cases;
  2796 
  2797 * HOL/List: "nodups" renamed to "distinct";
  2798 
  2799 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2800 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2801   - Ex_def has changed, now need to use some_eq_ex
  2802 
  2803 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2804 in this (rare) case use:
  2805 
  2806   delSWrapper "split_all_tac"
  2807   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2808 
  2809 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2810 MAY FAIL;
  2811 
  2812 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2813 Isabelle's type classes, ^ on functions and relations has too general
  2814 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2815 necessary to attach explicit type constraints;
  2816 
  2817 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2818 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2819 renamed accordingly (eg "compI" -> "rel_compI").
  2820 
  2821 * HOL: syntax translations now work properly with numerals and records
  2822 expressions;
  2823 
  2824 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2825 of "lam" -- INCOMPATIBILITY;
  2826 
  2827 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2828 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2829 renamed "Product_Type.unit";
  2830 
  2831 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2832 
  2833 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2834 the "cases" method);
  2835 
  2836 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2837 Florian Kammller);
  2838 
  2839 * HOL/IMP: updated and converted to new-style theory format; several
  2840 parts turned into readable document, with proper Isar proof texts and
  2841 some explanations (by Gerwin Klein);
  2842 
  2843 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2844 
  2845 * HOL-Hyperreal is now a logic image;
  2846 
  2847 
  2848 *** HOLCF ***
  2849 
  2850 * Isar: consts/constdefs supports mixfix syntax for continuous
  2851 operations;
  2852 
  2853 * Isar: domain package adapted to new-style theory format, e.g. see
  2854 HOLCF/ex/Dnat.thy;
  2855 
  2856 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2857 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2858 lift.induct_tac, always use UU instead of Undef;
  2859 
  2860 * HOLCF/IMP: updated and converted to new-style theory;
  2861 
  2862 
  2863 *** ZF ***
  2864 
  2865 * Isar: proper integration of logic-specific tools and packages,
  2866 including theory commands '(co)inductive', '(co)datatype',
  2867 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2868 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2869 
  2870 * theory Main no longer includes AC; for the Axiom of Choice, base
  2871 your theory on Main_ZFC;
  2872 
  2873 * the integer library now covers quotients and remainders, with many
  2874 laws relating division to addition, multiplication, etc.;
  2875 
  2876 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2877 typeless version of the formalism;
  2878 
  2879 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2880 format;
  2881 
  2882 * ZF/Induct: new directory for examples of inductive definitions,
  2883 including theory Multiset for multiset orderings; converted to
  2884 new-style theory format;
  2885 
  2886 * ZF: many new theorems about lists, ordinals, etc.;
  2887 
  2888 
  2889 *** General ***
  2890 
  2891 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2892 variable proof controls level of detail: 0 = no proofs (only oracle
  2893 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2894 also ref manual for further ML interfaces;
  2895 
  2896 * Pure/axclass: removed obsolete ML interface
  2897 goal_subclass/goal_arity;
  2898 
  2899 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2900 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2901 separate tokens, so expressions involving minus need to be spaced
  2902 properly;
  2903 
  2904 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2905 rather than "infixl" or "infixr";
  2906 
  2907 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2908 sort constraint specifications in type inference; e.g. "x::_::foo"
  2909 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2910 type variable);
  2911 
  2912 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2913 control output of nested => (types); the default behavior is
  2914 "type_brackets";
  2915 
  2916 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2917 tokens into AST constants;
  2918 
  2919 * Pure/syntax: prefer later declarations of translations and print
  2920 translation functions; potential INCOMPATIBILITY: need to reverse
  2921 multiple declarations for same syntax element constant;
  2922 
  2923 * Pure/show_hyps reset by default (in accordance to existing Isar
  2924 practice);
  2925 
  2926 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2927 addSafter;
  2928 
  2929 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2930 as well;
  2931 
  2932 * system: tested support for MacOS X; should be able to get Isabelle +
  2933 Proof General to work in a plain Terminal after installing Poly/ML
  2934 (e.g. from the Isabelle distribution area) and GNU bash alone
  2935 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2936 support requires further installations, e.g. from
  2937 http://fink.sourceforge.net/);
  2938 
  2939 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2940 
  2941 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2942 of 40 MB), cf. ML_OPTIONS;
  2943 
  2944 * system: Proof General keywords specification is now part of the
  2945 Isabelle distribution (see etc/isar-keywords.el);
  2946 
  2947 * system: support for persistent Proof General sessions (refrain from
  2948 outdating all loaded theories on startup); user may create writable
  2949 logic images like this: ``isabelle -q HOL Test'';
  2950 
  2951 * system: smart selection of Isabelle process versus Isabelle
  2952 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2953 run both "isabelle" and "Isabelle" even if file names are badly
  2954 damaged (executable inspects the case of the first letter of its own
  2955 name); added separate "isabelle-process" and "isabelle-interface";
  2956 
  2957 * system: refrain from any attempt at filtering input streams; no
  2958 longer support ``8bit'' encoding of old isabelle font, instead proper
  2959 iso-latin characters may now be used; the related isatools
  2960 "symbolinput" and "nonascii" have disappeared as well;
  2961 
  2962 * system: removed old "xterm" interface (the print modes "xterm" and
  2963 "xterm_color" are still available for direct use in a suitable
  2964 terminal);
  2965 
  2966 
  2967 
  2968 New in Isabelle99-2 (February 2001)
  2969 -----------------------------------
  2970 
  2971 *** Overview of INCOMPATIBILITIES ***
  2972 
  2973 * HOL: please note that theories in the Library and elsewhere often use the
  2974 new-style (Isar) format; to refer to their theorems in an ML script you must
  2975 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2976 
  2977 * HOL: inductive package no longer splits induction rule aggressively,
  2978 but only as far as specified by the introductions given; the old
  2979 format may be recovered via ML function complete_split_rule or attribute
  2980 'split_rule (complete)';
  2981 
  2982 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2983 gfp_Tarski to gfp_unfold;
  2984 
  2985 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2986 
  2987 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2988 relation); infix "^^" has been renamed "``"; infix "``" has been
  2989 renamed "`"; "univalent" has been renamed "single_valued";
  2990 
  2991 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2992 operation;
  2993 
  2994 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2995 
  2996 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2997 
  2998 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2999 consequence, it is no longer monotonic wrt. the local goal context
  3000 (which is now passed through the inductive cases);
  3001 
  3002 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3003 \<gg> to \<ggreater>;
  3004 
  3005 
  3006 *** Document preparation ***
  3007 
  3008 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3009 available: are "it" for near math-mode best-style output, "sl" for
  3010 slanted text style, and "tt" for plain type-writer; if no
  3011 \isabellestyle command is given, output is according to slanted
  3012 type-writer);
  3013 
  3014 * support sub/super scripts (for single symbols only), input syntax is
  3015 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3016 
  3017 * some more standard symbols; see Appendix A of the system manual for
  3018 the complete list of symbols defined in isabellesym.sty;
  3019 
  3020 * improved isabelle style files; more abstract symbol implementation
  3021 (should now use \isamath{...} and \isatext{...} in custom symbol
  3022 definitions);
  3023 
  3024 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3025 state; Note that presentation of goal states does not conform to
  3026 actual human-readable proof documents.  Please do not include goal
  3027 states into document output unless you really know what you are doing!
  3028 
  3029 * proper indentation of antiquoted output with proportional LaTeX
  3030 fonts;
  3031 
  3032 * no_document ML operator temporarily disables LaTeX document
  3033 generation;
  3034 
  3035 * isatool unsymbolize tunes sources for plain ASCII communication;
  3036 
  3037 
  3038 *** Isar ***
  3039 
  3040 * Pure: Isar now suffers initial goal statements to contain unbound
  3041 schematic variables (this does not conform to actual readable proof
  3042 documents, due to unpredictable outcome and non-compositional proof
  3043 checking); users who know what they are doing may use schematic goals
  3044 for Prolog-style synthesis of proven results;
  3045 
  3046 * Pure: assumption method (an implicit finishing) now handles actual
  3047 rules as well;
  3048 
  3049 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3050 initial goal, declare "that" only as Pure intro (only for single
  3051 steps); the "that" rule assumption may now be involved in implicit
  3052 finishing, thus ".." becomes a feasible for trivial obtains;
  3053 
  3054 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3055 instance proofs may be performed by "..";
  3056 
  3057 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3058 statements as well;
  3059 
  3060 * Pure: more robust selection of calculational rules;
  3061 
  3062 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3063 rule (as well as the assumption rule);
  3064 
  3065 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3066 lemmas, using the graph browser tool;
  3067 
  3068 * Pure: predict failure of "show" in interactive mode;
  3069 
  3070 * Pure: 'thms_containing' now takes actual terms as arguments;
  3071 
  3072 * HOL: improved method 'induct' --- now handles non-atomic goals
  3073 (potential INCOMPATIBILITY); tuned error handling;
  3074 
  3075 * HOL: cases and induct rules now provide explicit hints about the
  3076 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3077 any remaining facts are inserted into the goal verbatim;
  3078 
  3079 * HOL: local contexts (aka cases) may now contain term bindings as
  3080 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3081 the result to be shown in each case;
  3082 
  3083 * HOL: added 'recdef_tc' command;
  3084 
  3085 * isatool convert assists in eliminating legacy ML scripts;
  3086 
  3087 
  3088 *** HOL ***
  3089 
  3090 * HOL/Library: a collection of generic theories to be used together
  3091 with main HOL; the theory loader path already includes this directory
  3092 by default; the following existing theories have been moved here:
  3093 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3094 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3095 
  3096 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3097 modelling and verification task performed in Isabelle/HOL +
  3098 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3099 
  3100 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3101 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3102 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3103 'domain', this makes the theory consistent with mathematical
  3104 literature;
  3105 
  3106 * HOL basics: added overloaded operations "inverse" and "divide"
  3107 (infix "/"), syntax for generic "abs" operation, generic summation
  3108 operator \<Sum>;
  3109 
  3110 * HOL/typedef: simplified package, provide more useful rules (see also
  3111 HOL/subset.thy);
  3112 
  3113 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3114 now expressed as a proper nested rule (old-style tactic scripts may
  3115 require atomize_strip_tac to cope with non-atomic premises);
  3116 
  3117 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3118 to "split_conv" (old name still available for compatibility);
  3119 
  3120 * HOL: improved concrete syntax for strings (e.g. allows translation
  3121 rules with string literals);
  3122 
  3123 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3124  and Fleuriot's mechanization of analysis, including the transcendental
  3125  functions for the reals;
  3126 
  3127 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3128 
  3129 
  3130 *** CTT ***
  3131 
  3132 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3133 "lam" is displayed as TWO lambda-symbols
  3134 
  3135 * CTT: theory Main now available, containing everything (that is, Bool
  3136 and Arith);
  3137 
  3138 
  3139 *** General ***
  3140 
  3141 * Pure: the Simplifier has been implemented properly as a derived rule
  3142 outside of the actual kernel (at last!); the overall performance
  3143 penalty in practical applications is about 50%, while reliability of
  3144 the Isabelle inference kernel has been greatly improved;
  3145 
  3146 * print modes "brackets" and "no_brackets" control output of nested =>
  3147 (types) and ==> (props); the default behaviour is "brackets";
  3148 
  3149 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3150 as assumptions as well;
  3151 
  3152 * system: support Poly/ML 4.0;
  3153 
  3154 * system: isatool install handles KDE version 1 or 2;
  3155 
  3156 
  3157 
  3158 New in Isabelle99-1 (October 2000)
  3159 ----------------------------------
  3160 
  3161 *** Overview of INCOMPATIBILITIES ***
  3162 
  3163 * HOL: simplification of natural numbers is much changed; to partly
  3164 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3165 issue the following ML commands:
  3166 
  3167   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3168   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3169 
  3170 * HOL: simplification no longer dives into case-expressions; this is
  3171 controlled by "t.weak_case_cong" for each datatype t;
  3172 
  3173 * HOL: nat_less_induct renamed to less_induct;
  3174 
  3175 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3176 fixsome to patch .thy and .ML sources automatically;
  3177 
  3178   select_equality  -> some_equality
  3179   select_eq_Ex     -> some_eq_ex
  3180   selectI2EX       -> someI2_ex
  3181   selectI2         -> someI2
  3182   selectI          -> someI
  3183   select1_equality -> some1_equality
  3184   Eps_sym_eq       -> some_sym_eq_trivial
  3185   Eps_eq           -> some_eq_trivial
  3186 
  3187 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3188 
  3189 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3190 instead);
  3191 
  3192 * HOL: the recursion equations generated by 'recdef' are now called
  3193 f.simps instead of f.rules;
  3194 
  3195 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3196 
  3197 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3198 sometimes be needed;
  3199 
  3200 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3201 
  3202 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3203 
  3204 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3205 product is now "<*>" instead of "Times"; the lexicographic product is
  3206 now "<*lex*>" instead of "**";
  3207 
  3208 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3209 of main HOL, but was unused); better use HOL's datatype package;
  3210 
  3211 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3212 the old syntax may be recovered as follows:
  3213 
  3214   syntax (symbols)
  3215     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3216       (infixl "\\<oplus>" 100)
  3217 
  3218 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3219 
  3220 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3221 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3222 internally;
  3223 
  3224 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3225 changed from A/r to A//r;
  3226 
  3227 * ZF: new treatment of arithmetic (nat & int) may break some old
  3228 proofs;
  3229 
  3230 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3231 rulify -> rule_format, elimify -> elim_format, ...);
  3232 
  3233 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3234 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3235 should have to change intro!! to intro? only); replaced "delrule" by
  3236 "rule del";
  3237 
  3238 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3239 
  3240 * Provers: strengthened force_tac by using new first_best_tac;
  3241 
  3242 * LaTeX document preparation: several changes of isabelle.sty (see
  3243 lib/texinputs);
  3244 
  3245 
  3246 *** Document preparation ***
  3247 
  3248 * formal comments (text blocks etc.) in new-style theories may now
  3249 contain antiquotations of thm/prop/term/typ/text to be presented
  3250 according to latex print mode; concrete syntax is like this:
  3251 @{term[show_types] "f(x) = a + x"};
  3252 
  3253 * isatool mkdir provides easy setup of Isabelle session directories,
  3254 including proper document sources;
  3255 
  3256 * generated LaTeX sources are now deleted after successful run
  3257 (isatool document -c); may retain a copy somewhere else via -D option
  3258 of isatool usedir;
  3259 
  3260 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3261 style files, achieving self-contained LaTeX sources and simplifying
  3262 LaTeX debugging;
  3263 
  3264 * old-style theories now produce (crude) LaTeX output as well;
  3265 
  3266 * browser info session directories are now self-contained (may be put
  3267 on WWW server seperately); improved graphs of nested sessions; removed
  3268 graph for 'all sessions';
  3269 
  3270 * several improvements in isabelle style files; \isabellestyle{it}
  3271 produces fake math mode output; \isamarkupheader is now \section by
  3272 default; see lib/texinputs/isabelle.sty etc.;
  3273 
  3274 
  3275 *** Isar ***
  3276 
  3277 * Isar/Pure: local results and corresponding term bindings are now
  3278 subject to Hindley-Milner polymorphism (similar to ML); this
  3279 accommodates incremental type-inference very nicely;
  3280 
  3281 * Isar/Pure: new derived language element 'obtain' supports
  3282 generalized existence reasoning;
  3283 
  3284 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3285 support accumulation of results, without applying any rules yet;
  3286 useful to collect intermediate results without explicit name
  3287 references, and for use with transitivity rules with more than 2
  3288 premises;
  3289 
  3290 * Isar/Pure: scalable support for case-analysis type proofs: new
  3291 'case' language element refers to local contexts symbolically, as
  3292 produced by certain proof methods; internally, case names are attached
  3293 to theorems as "tags";
  3294 
  3295 * Isar/Pure: theory command 'hide' removes declarations from
  3296 class/type/const name spaces;
  3297 
  3298 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3299 indicate potential overloading;
  3300 
  3301 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3302 
  3303 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3304 "{a,b,c}" instead of {a,b,c};
  3305 
  3306 * Isar/Pure now provides its own version of intro/elim/dest
  3307 attributes; useful for building new logics, but beware of confusion
  3308 with the version in Provers/classical;
  3309 
  3310 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3311 case name 'antecedent';
  3312 
  3313 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3314 to the current context is now done automatically);
  3315 
  3316 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3317 for definining proof methods in ML;
  3318 
  3319 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3320 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3321 most cases, one should have to change intro!! to intro? only);
  3322 replaced "delrule" by "rule del";
  3323 
  3324 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3325 'symmetric' attribute (the latter supercedes [RS sym]);
  3326 
  3327 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3328 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3329 well (including splits);
  3330 
  3331 * Isar/Provers: Simplifier and Classical methods now support all kind
  3332 of modifiers used in the past, including 'cong', 'iff', etc.
  3333 
  3334 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3335 of Simplifier and Classical reasoner);
  3336 
  3337 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3338 now support named cases; major packages (inductive, datatype, primrec,
  3339 recdef) support case names and properly name parameters;
  3340 
  3341 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3342 monotonicity conditions are extracted to be proven at end of
  3343 calculations;
  3344 
  3345 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3346 method anyway;
  3347 
  3348 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3349 split_if split_if_asm; datatype package provides theorems foo.splits =
  3350 foo.split foo.split_asm for each datatype;
  3351 
  3352 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3353 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3354 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3355 use "(cases (simplified))" method in proper proof texts);
  3356 
  3357 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3358 
  3359 * Isar: names of theorems etc. may be natural numbers as well;
  3360 
  3361 * Isar: 'pr' command: optional arguments for goals_limit and
  3362 ProofContext.prems_limit; no longer prints theory contexts, but only
  3363 proof states;
  3364 
  3365 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3366 additional print modes to be specified; e.g. "pr(latex)" will print
  3367 proof state according to the Isabelle LaTeX style;
  3368 
  3369 * Isar: improved support for emulating tactic scripts, including proof
  3370 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3371 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3372 (for HOL datatypes);
  3373 
  3374 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3375 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3376 'proof method scripts' have to be in depth-first order;
  3377 
  3378 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3379 
  3380 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3381 should instead use individual commands for printing items
  3382 (print_commands, print_methods etc.);
  3383 
  3384 * Isar: added 'nothing' --- the empty list of theorems;
  3385 
  3386 
  3387 *** HOL ***
  3388 
  3389 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3390 corresponding virtual machine and a specification of its bytecode
  3391 verifier and a lightweight bytecode verifier, including proofs of
  3392 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3393 Cornelia Pusch (see also the homepage of project Bali at
  3394 http://isabelle.in.tum.de/Bali/);
  3395 
  3396 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3397 Clemens Ballarin;
  3398 
  3399 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3400 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3401 Rasmussen;
  3402 
  3403 * HOL/Lattice: fundamental concepts of lattice theory and order
  3404 structures, including duals, properties of bounds versus algebraic
  3405 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3406 Theorem for complete lattices etc.; may also serve as a demonstration
  3407 for abstract algebraic reasoning using axiomatic type classes, and
  3408 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3409 
  3410 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3411 von Oheimb;
  3412 
  3413 * HOL/IMPP: extension of IMP with local variables and mutually
  3414 recursive procedures, by David von Oheimb;
  3415 
  3416 * HOL/Lambda: converted into new-style theory and document;
  3417 
  3418 * HOL/ex/Multiquote: example of multiple nested quotations and
  3419 anti-quotations -- basically a generalized version of de-Bruijn
  3420 representation; very useful in avoiding lifting of operations;
  3421 
  3422 * HOL/record: added general record equality rule to simpset; fixed
  3423 select-update simplification procedure to handle extended records as
  3424 well; admit "r" as field name;
  3425 
  3426 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3427 other numeric types and also as the identity of groups, rings, etc.;
  3428 
  3429 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3430 Types nat and int belong to this axclass;
  3431 
  3432 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3433    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3434    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3435   two terms #m*u and #n*u are replaced by #(m+n)*u
  3436     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3437   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3438     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3439 
  3440 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3441 powerful prover for predicate logic but knows nothing of clasets; see
  3442 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3443 
  3444 * HOL: new version of "case_tac" subsumes both boolean case split and
  3445 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3446 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3447 
  3448 * HOL: simplification no longer dives into case-expressions: only the
  3449 selector expression is simplified, but not the remaining arms; to
  3450 enable full simplification of case-expressions for datatype t, you may
  3451 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3452 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3453 
  3454 * HOL/recdef: the recursion equations generated by 'recdef' for
  3455 function 'f' are now called f.simps instead of f.rules; if all
  3456 termination conditions are proved automatically, these simplification
  3457 rules are added to the simpset, as in primrec; rules may be named
  3458 individually as well, resulting in a separate list of theorems for
  3459 each equation;
  3460 
  3461 * HOL/While is a new theory that provides a while-combinator. It
  3462 permits the definition of tail-recursive functions without the
  3463 provision of a termination measure. The latter is necessary once the
  3464 invariant proof rule for while is applied.
  3465 
  3466 * HOL: new (overloaded) notation for the set of elements below/above
  3467 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3468 
  3469 * HOL: theorems impI, allI, ballI bound as "strip";
  3470 
  3471 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3472 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3473 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3474 
  3475 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3476 
  3477 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3478 main HOL, but was unused);
  3479 
  3480 * HOL: fewer consts declared as global (e.g. have to refer to
  3481 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3482 
  3483 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3484 in case of overlap with user translations (e.g. judgements over
  3485 tuples); (note that the underlying logical represenation is still
  3486 bogus);
  3487 
  3488 
  3489 *** ZF ***
  3490 
  3491 * ZF: simplification automatically cancels common terms in arithmetic
  3492 expressions over nat and int;
  3493 
  3494 * ZF: new treatment of nat to minimize type-checking: all operators
  3495 coerce their operands to a natural number using the function natify,
  3496 making the algebraic laws unconditional;
  3497 
  3498 * ZF: as above, for int: operators coerce their operands to an integer
  3499 using the function intify;
  3500 
  3501 * ZF: the integer library now contains many of the usual laws for the
  3502 orderings, including $<=, and monotonicity laws for $+ and $*;
  3503 
  3504 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3505 simplification;
  3506 
  3507 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3508 to the simplifier and classical reasoner simultaneously;
  3509 
  3510 
  3511 *** General ***
  3512 
  3513 * Provers: blast_tac now handles actual object-logic rules as
  3514 assumptions; note that auto_tac uses blast_tac internally as well;
  3515 
  3516 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3517 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3518 
  3519 * Provers: delrules now handles destruct rules as well (no longer need
  3520 explicit make_elim);
  3521 
  3522 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3523   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3524 use instead the strong form,
  3525   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3526 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3527 from destruct-rules;
  3528 
  3529 * Provers: Simplifier.easy_setup provides a fast path to basic
  3530 Simplifier setup for new object-logics;
  3531 
  3532 * Pure: AST translation rules no longer require constant head on LHS;
  3533 
  3534 * Pure: improved name spaces: ambiguous output is qualified; support
  3535 for hiding of names;
  3536 
  3537 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3538 XSYMBOL_HOME; no longer need to do manual configuration in most
  3539 situations;
  3540 
  3541 * system: compression of ML heaps images may now be controlled via -c
  3542 option of isabelle and isatool usedir (currently only observed by
  3543 Poly/ML);
  3544 
  3545 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3546 useful for remote X11);
  3547 
  3548 * system: provide TAGS file for Isabelle sources;
  3549 
  3550 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3551 order;
  3552 
  3553 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3554 timing flag supersedes proof_timing and Toplevel.trace;
  3555 
  3556 * ML: new combinators |>> and |>>> for incremental transformations
  3557 with secondary results (e.g. certain theory extensions):
  3558 
  3559 * ML: PureThy.add_defs gets additional argument to indicate potential
  3560 overloading (usually false);
  3561 
  3562 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3563 results;
  3564 
  3565 
  3566 
  3567 New in Isabelle99 (October 1999)
  3568 --------------------------------
  3569 
  3570 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3571 
  3572 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3573 are no longer simplified.  (This allows the simplifier to unfold recursive
  3574 functional programs.)  To restore the old behaviour, declare
  3575 
  3576     Delcongs [if_weak_cong];
  3577 
  3578 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3579 complement;
  3580 
  3581 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3582 
  3583 * HOL/datatype: mutual_induct_tac no longer exists --
  3584   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3585 
  3586 * HOL/typedef: fixed type inference for representing set; type
  3587 arguments now have to occur explicitly on the rhs as type constraints;
  3588 
  3589 * ZF: The con_defs part of an inductive definition may no longer refer
  3590 to constants declared in the same theory;
  3591 
  3592 * HOL, ZF: the function mk_cases, generated by the inductive
  3593 definition package, has lost an argument.  To simplify its result, it
  3594 uses the default simpset instead of a supplied list of theorems.
  3595 
  3596 * HOL/List: the constructors of type list are now Nil and Cons;
  3597 
  3598 * Simplifier: the type of the infix ML functions
  3599         setSSolver addSSolver setSolver addSolver
  3600 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3601 for packaging solvers. A solver is created via
  3602         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3603 where the string argument is only a comment.
  3604 
  3605 
  3606 *** Proof tools ***
  3607 
  3608 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3609 decision procedure for linear arithmetic. Currently it is used for
  3610 types `nat', `int', and `real' in HOL (see below); it can, should and
  3611 will be instantiated for other types and logics as well.
  3612 
  3613 * The simplifier now accepts rewrite rules with flexible heads, eg
  3614      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3615   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3616   matching.
  3617 
  3618 
  3619 *** General ***
  3620 
  3621 * New Isabelle/Isar subsystem provides an alternative to traditional
  3622 tactical theorem proving; together with the ProofGeneral/isar user
  3623 interface it offers an interactive environment for developing human
  3624 readable proof documents (Isar == Intelligible semi-automated
  3625 reasoning); for further information see isatool doc isar-ref,
  3626 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3627 
  3628 * improved and simplified presentation of theories: better HTML markup
  3629 (including colors), graph views in several sizes; isatool usedir now
  3630 provides a proper interface for user theories (via -P option); actual
  3631 document preparation based on (PDF)LaTeX is available as well (for
  3632 new-style theories only); see isatool doc system for more information;
  3633 
  3634 * native support for Proof General, both for classic Isabelle and
  3635 Isabelle/Isar;
  3636 
  3637 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3638 using the graph browser tool;
  3639 
  3640 * Isabelle manuals now also available as PDF;
  3641 
  3642 * theory loader rewritten from scratch (may not be fully
  3643 bug-compatible); old loadpath variable has been replaced by show_path,
  3644 add_path, del_path, reset_path functions; new operations such as
  3645 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3646 isatool doc ref);
  3647 
  3648 * improved isatool install: option -k creates KDE application icon,
  3649 option -p DIR installs standalone binaries;
  3650 
  3651 * added ML_PLATFORM setting (useful for cross-platform installations);
  3652 more robust handling of platform specific ML images for SML/NJ;
  3653 
  3654 * the settings environment is now statically scoped, i.e. it is never
  3655 created again in sub-processes invoked from isabelle, isatool, or
  3656 Isabelle;
  3657 
  3658 * path element specification '~~' refers to '$ISABELLE_HOME';
  3659 
  3660 * in locales, the "assumes" and "defines" parts may be omitted if
  3661 empty;
  3662 
  3663 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3664 long arrows);
  3665 
  3666 * new print_mode "HTML";
  3667 
  3668 * new flag show_tags controls display of tags of theorems (which are
  3669 basically just comments that may be attached by some tools);
  3670 
  3671 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3672 mode and goal output format:
  3673 
  3674 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3675 244c244
  3676 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3677 ---
  3678 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3679 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3680 181c181
  3681 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3682 ---
  3683 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3684 
  3685 * function bind_thms stores lists of theorems (cf. bind_thm);
  3686 
  3687 * new shorthand tactics ftac, eatac, datac, fatac;
  3688 
  3689 * qed (and friends) now accept "" as result name; in that case the
  3690 theorem is not stored, but proper checks and presentation of the
  3691 result still apply;
  3692 
  3693 * theorem database now also indexes constants "Trueprop", "all",
  3694 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3695 
  3696 
  3697 *** HOL ***
  3698 
  3699 ** HOL arithmetic **
  3700 
  3701 * There are now decision procedures for linear arithmetic over nat and
  3702 int:
  3703 
  3704 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3705 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3706 are treated as atomic; subformulae not involving type `nat' or `int'
  3707 are ignored; quantified subformulae are ignored unless they are
  3708 positive universal or negative existential. The tactic has to be
  3709 invoked by hand and can be a little bit slow. In particular, the
  3710 running time is exponential in the number of occurrences of `min' and
  3711 `max', and `-' on `nat'.
  3712 
  3713 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3714 (negated) (in)equalities among the premises and the conclusion into
  3715 account (i.e. no compound formulae) and does not know about `min' and
  3716 `max', and `-' on `nat'. It is fast and is used automatically by the
  3717 simplifier.
  3718 
  3719 NB: At the moment, these decision procedures do not cope with mixed
  3720 nat/int formulae where the two parts interact, such as `m < n ==>
  3721 int(m) < int(n)'.
  3722 
  3723 * HOL/Numeral provides a generic theory of numerals (encoded
  3724 efficiently as bit strings); setup for types nat/int/real is in place;
  3725 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3726 int, existing theories and proof scripts may require a few additional
  3727 type constraints;
  3728 
  3729 * integer division and remainder can now be performed on constant
  3730 arguments;
  3731 
  3732 * many properties of integer multiplication, division and remainder
  3733 are now available;
  3734 
  3735 * An interface to the Stanford Validity Checker (SVC) is available through the
  3736 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3737 are proved automatically.  SVC must be installed separately, and its results
  3738 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3739 invocation of the underlying oracle).  For SVC see
  3740   http://verify.stanford.edu/SVC
  3741 
  3742 * IsaMakefile: the HOL-Real target now builds an actual image;
  3743 
  3744 
  3745 ** HOL misc **
  3746 
  3747 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3748 (in Isabelle/Isar) -- by Gertrud Bauer;
  3749 
  3750 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3751 analysis for assembly languages with subtypes;
  3752 
  3753 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3754 -- avoids syntactic ambiguities and treats state, transition, and
  3755 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3756 changed syntax and (many) tactics;
  3757 
  3758 * HOL/inductive: Now also handles more general introduction rules such
  3759   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3760   theorems are now maintained within the theory (maintained via the
  3761   "mono" attribute);
  3762 
  3763 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3764   (using function types) such as
  3765 
  3766   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3767 
  3768 * HOL/record: record_simproc (part of the default simpset) takes care
  3769 of selectors applied to updated records; record_split_tac is no longer
  3770 part of the default claset; update_defs may now be removed from the
  3771 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3772 
  3773   claset_ref () := claset() addSWrapper record_split_wrapper;
  3774   Delsimprocs [record_simproc]
  3775 
  3776 * HOL/typedef: fixed type inference for representing set; type
  3777 arguments now have to occur explicitly on the rhs as type constraints;
  3778 
  3779 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3780 names rather than an ML expression;
  3781 
  3782 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3783 supplied later.  Program schemes can be defined, such as
  3784     "While B C s = (if B s then While B C (C s) else s)"
  3785 where the well-founded relation can be chosen after B and C have been given.
  3786 
  3787 * HOL/List: the constructors of type list are now Nil and Cons;
  3788 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3789 course, ML tools referring to List.list.op # etc. have to be adapted;
  3790 
  3791 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3792 disabled by default; run isabelle with option -m HOL to get back to
  3793 the original Gordon/HOL-style output;
  3794 
  3795 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3796 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3797 
  3798 * HOL basic syntax simplified (more orthogonal): all variants of
  3799 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3800 Eps operator is provided as well: "SOME x. P[x]";
  3801 
  3802 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3803 
  3804 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3805 thus available for user theories;
  3806 
  3807 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3808 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3809 time;
  3810 
  3811 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3812 several times and then mp;
  3813 
  3814 
  3815 *** LK ***
  3816 
  3817 * the notation <<...>> is now available as a notation for sequences of
  3818 formulas;
  3819 
  3820 * the simplifier is now installed
  3821 
  3822 * the axiom system has been generalized (thanks to Soren Heilmann)
  3823 
  3824 * the classical reasoner now has a default rule database
  3825 
  3826 
  3827 *** ZF ***
  3828 
  3829 * new primrec section allows primitive recursive functions to be given
  3830 directly (as in HOL) over datatypes and the natural numbers;
  3831 
  3832 * new tactics induct_tac and exhaust_tac for induction (or case
  3833 analysis) over datatypes and the natural numbers;
  3834 
  3835 * the datatype declaration of type T now defines the recursor T_rec;
  3836 
  3837 * simplification automatically does freeness reasoning for datatype
  3838 constructors;
  3839 
  3840 * automatic type-inference, with AddTCs command to insert new
  3841 type-checking rules;
  3842 
  3843 * datatype introduction rules are now added as Safe Introduction rules
  3844 to the claset;
  3845 
  3846 * the syntax "if P then x else y" is now available in addition to
  3847 if(P,x,y);
  3848 
  3849 
  3850 *** Internal programming interfaces ***
  3851 
  3852 * tuned simplifier trace output; new flag debug_simp;
  3853 
  3854 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3855 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3856 
  3857 * AxClass.axclass_tac lost the theory argument;
  3858 
  3859 * tuned current_goals_markers semantics: begin / end goal avoids
  3860 printing empty lines;
  3861 
  3862 * removed prs and prs_fn hook, which was broken because it did not
  3863 include \n in its semantics, forcing writeln to add one
  3864 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3865 string -> unit if you really want to output text without newline;
  3866 
  3867 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3868 plain output, interface builders may have to enable 'isabelle_font'
  3869 mode to get Isabelle font glyphs as before;
  3870 
  3871 * refined token_translation interface; INCOMPATIBILITY: output length
  3872 now of type real instead of int;
  3873 
  3874 * theory loader actions may be traced via new ThyInfo.add_hook
  3875 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3876 your own database of information attached to *whole* theories -- as
  3877 opposed to intra-theory data slots offered via TheoryDataFun;
  3878 
  3879 * proper handling of dangling sort hypotheses (at last!);
  3880 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3881 extra sort hypotheses that can be witnessed from the type signature;
  3882 the force_strip_shyps flag is gone, any remaining shyps are simply
  3883 left in the theorem (with a warning issued by strip_shyps_warning);
  3884 
  3885 
  3886 
  3887 New in Isabelle98-1 (October 1998)
  3888 ----------------------------------
  3889 
  3890 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3891 
  3892 * several changes of automated proof tools;
  3893 
  3894 * HOL: major changes to the inductive and datatype packages, including
  3895 some minor incompatibilities of theory syntax;
  3896 
  3897 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3898 called `inj_on';
  3899 
  3900 * HOL: removed duplicate thms in Arith:
  3901   less_imp_add_less  should be replaced by  trans_less_add1
  3902   le_imp_add_le      should be replaced by  trans_le_add1
  3903 
  3904 * HOL: unary minus is now overloaded (new type constraints may be
  3905 required);
  3906 
  3907 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3908 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3909 now taken as an integer constant.
  3910 
  3911 * Pure: ML function 'theory_of' renamed to 'theory';
  3912 
  3913 
  3914 *** Proof tools ***
  3915 
  3916 * Simplifier:
  3917   1. Asm_full_simp_tac is now more aggressive.
  3918      1. It will sometimes reorient premises if that increases their power to
  3919         simplify.
  3920      2. It does no longer proceed strictly from left to right but may also
  3921         rotate premises to achieve further simplification.
  3922      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3923      old Asm_full_simp_tac in that it does not rotate premises.
  3924   2. The simplifier now knows a little bit about nat-arithmetic.
  3925 
  3926 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3927 allows for selected deletion of wrappers, by introduction of names for
  3928 wrapper functionals.  This implies that addbefore, addSbefore,
  3929 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3930 and that adding two tactics with the same name overwrites the first
  3931 one (emitting a warning).
  3932   type wrapper = (int -> tactic) -> (int -> tactic)
  3933   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3934   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3935   delWrapper, delSWrapper: claset *  string            -> claset
  3936   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3937 
  3938 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3939 semantics; addbefore now affects only the unsafe part of step_tac
  3940 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3941 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3942 by Force_tac;
  3943 
  3944 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3945 compWrapper; added safe wrapper (and access functions for it);
  3946 
  3947 * HOL/split_all_tac is now much faster and fails if there is nothing
  3948 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3949 and the names of the automatically generated variables have changed.
  3950 split_all_tac has moved within claset() from unsafe wrappers to safe
  3951 wrappers, which means that !!-bound variables are split much more
  3952 aggressively, and safe_tac and clarify_tac now split such variables.
  3953 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3954 Note: the same holds for record_split_tac, which does the job of
  3955 split_all_tac for record fields.
  3956 
  3957 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3958 permanently to the default simpset using Addsplits just like
  3959 Addsimps. They can be removed via Delsplits just like
  3960 Delsimps. Lower-case versions are also available.
  3961 
  3962 * HOL/Simplifier: The rule split_if is now part of the default
  3963 simpset. This means that the simplifier will eliminate all occurrences
  3964 of if-then-else in the conclusion of a goal. To prevent this, you can
  3965 either remove split_if completely from the default simpset by
  3966 `Delsplits [split_if]' or remove it in a specific call of the
  3967 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3968 other case splitting rules to/from the default simpset: every datatype
  3969 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3970 t is the name of the datatype).
  3971 
  3972 * Classical reasoner / Simplifier combination: new force_tac (and
  3973 derivatives Force_tac, force) combines rewriting and classical
  3974 reasoning (and whatever other tools) similarly to auto_tac, but is
  3975 aimed to solve the given subgoal completely.
  3976 
  3977 
  3978 *** General ***
  3979 
  3980 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3981 and `goalw': the theory is no longer needed as an explicit argument -
  3982 the current theory context is used; assumptions are no longer returned
  3983 at the ML-level unless one of them starts with ==> or !!; it is
  3984 recommended to convert to these new commands using isatool fixgoal
  3985 (backup your sources first!);
  3986 
  3987 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3988 the current theory context, and 'theory' to lookup stored theories;
  3989 
  3990 * new theory section 'locale' for declaring constants, assumptions and
  3991 definitions that have local scope;
  3992 
  3993 * new theory section 'nonterminals' for purely syntactic types;
  3994 
  3995 * new theory section 'setup' for generic ML setup functions
  3996 (e.g. package initialization);
  3997 
  3998 * the distribution now includes Isabelle icons: see
  3999 lib/logo/isabelle-{small,tiny}.xpm;
  4000 
  4001 * isatool install - install binaries with absolute references to
  4002 ISABELLE_HOME/bin;
  4003 
  4004 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4005 
  4006 * print mode 'emacs' reserved for Isamode;
  4007 
  4008 * support multiple print (ast) translations per constant name;
  4009 
  4010 * theorems involving oracles are now printed with a suffixed [!];
  4011 
  4012 
  4013 *** HOL ***
  4014 
  4015 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4016 
  4017 * HOL/inductive package reorganized and improved: now supports mutual
  4018 definitions such as
  4019 
  4020   inductive EVEN ODD
  4021     intrs
  4022       null "0 : EVEN"
  4023       oddI "n : EVEN ==> Suc n : ODD"
  4024       evenI "n : ODD ==> Suc n : EVEN"
  4025 
  4026 new theorem list "elims" contains an elimination rule for each of the
  4027 recursive sets; inductive definitions now handle disjunctive premises
  4028 correctly (also ZF);
  4029 
  4030 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4031 "mutual_induct" no longer exists - the induction rule is always
  4032 contained in "induct";
  4033 
  4034 
  4035 * HOL/datatype package re-implemented and greatly improved: now
  4036 supports mutually recursive datatypes such as
  4037 
  4038   datatype
  4039     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4040             | SUM ('a aexp) ('a aexp)
  4041             | DIFF ('a aexp) ('a aexp)
  4042             | NUM 'a
  4043   and
  4044     'a bexp = LESS ('a aexp) ('a aexp)
  4045             | AND ('a bexp) ('a bexp)
  4046             | OR ('a bexp) ('a bexp)
  4047 
  4048 as well as indirectly recursive datatypes such as
  4049 
  4050   datatype
  4051     ('a, 'b) term = Var 'a
  4052                   | App 'b ((('a, 'b) term) list)
  4053 
  4054 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4055 induction on mutually / indirectly recursive datatypes.
  4056 
  4057 Primrec equations are now stored in theory and can be accessed via
  4058 <function_name>.simps.
  4059 
  4060 INCOMPATIBILITIES:
  4061 
  4062   - Theories using datatypes must now have theory Datatype as an
  4063     ancestor.
  4064   - The specific <typename>.induct_tac no longer exists - use the
  4065     generic induct_tac instead.
  4066   - natE has been renamed to nat.exhaust - use exhaust_tac
  4067     instead of res_inst_tac ... natE. Note that the variable
  4068     names in nat.exhaust differ from the names in natE, this
  4069     may cause some "fragile" proofs to fail.
  4070   - The theorems split_<typename>_case and split_<typename>_case_asm
  4071     have been renamed to <typename>.split and <typename>.split_asm.
  4072   - Since default sorts of type variables are now handled correctly,
  4073     some datatype definitions may have to be annotated with explicit
  4074     sort constraints.
  4075   - Primrec definitions no longer require function name and type
  4076     of recursive argument.
  4077 
  4078 Consider using isatool fixdatatype to adapt your theories and proof
  4079 scripts to the new package (backup your sources first!).
  4080 
  4081 
  4082 * HOL/record package: considerably improved implementation; now
  4083 includes concrete syntax for record types, terms, updates; theorems
  4084 for surjective pairing and splitting !!-bound record variables; proof
  4085 support is as follows:
  4086 
  4087   1) standard conversions (selectors or updates applied to record
  4088 constructor terms) are part of the standard simpset;
  4089 
  4090   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4091 made part of standard simpset and claset via addIffs;
  4092 
  4093   3) a tactic for record field splitting (record_split_tac) is part of
  4094 the standard claset (addSWrapper);
  4095 
  4096 To get a better idea about these rules you may retrieve them via
  4097 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4098 the name of your record type.
  4099 
  4100 The split tactic 3) conceptually simplifies by the following rule:
  4101 
  4102   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4103 
  4104 Thus any record variable that is bound by meta-all will automatically
  4105 blow up into some record constructor term, consequently the
  4106 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4107 solve record problems automatically.
  4108 
  4109 
  4110 * reorganized the main HOL image: HOL/Integ and String loaded by
  4111 default; theory Main includes everything;
  4112 
  4113 * automatic simplification of integer sums and comparisons, using cancellation;
  4114 
  4115 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4116 
  4117 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4118 
  4119 * many new identities for unions, intersections, set difference, etc.;
  4120 
  4121 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4122 called split_if, split_split, split_sum_case and split_nat_case (to go
  4123 with add/delsplits);
  4124 
  4125 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4126 (?x::unit) = (); this is made part of the default simpset, which COULD
  4127 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4128 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4129 unit_abs_eta_conv is added in order to counter the effect of
  4130 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4131 %u.f();
  4132 
  4133 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4134 makes more sense);
  4135 
  4136 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4137   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4138   disjointness reasoning but breaking a few old proofs.
  4139 
  4140 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4141 to 'converse' from 'inverse' (for compatibility with ZF and some
  4142 literature);
  4143 
  4144 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4145 the well-founded relation;
  4146 
  4147 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4148     Compl A.  The "Compl" syntax remains available as input syntax for this
  4149     release ONLY.
  4150 
  4151 * HOL/Update: new theory of function updates:
  4152     f(a:=b) == %x. if x=a then b else f x
  4153 may also be iterated as in f(a:=b,c:=d,...);
  4154 
  4155 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4156 
  4157 * HOL/List:
  4158   - new function list_update written xs[i:=v] that updates the i-th
  4159     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4160   - new function `upt' written [i..j(] which generates the list
  4161     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4162     bound write [i..j], which is a shorthand for [i..j+1(].
  4163   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4164 
  4165 * HOL/Arith:
  4166   - removed 'pred' (predecessor) function;
  4167   - generalized some theorems about n-1;
  4168   - many new laws about "div" and "mod";
  4169   - new laws about greatest common divisors (see theory ex/Primes);
  4170 
  4171 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4172 instead of "inverse";
  4173 
  4174 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4175   of the multiset ordering;
  4176 
  4177 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4178   (not included by default);
  4179 
  4180 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4181 
  4182 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4183   programs, i.e. different program variables may have different types.
  4184 
  4185 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4186   [previously, this check worked only if the rewrite rule was unconditional]
  4187   Now rew can involve either definitions or equalities (either == or =).
  4188 
  4189 
  4190 *** ZF ***
  4191 
  4192 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4193   only the theorems proved on ZF.ML;
  4194 
  4195 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4196   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4197   disjointness reasoning but breaking a few old proofs.
  4198 
  4199 * ZF/Update: new theory of function updates
  4200     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4201   may also be iterated as in f(a:=b,c:=d,...);
  4202 
  4203 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4204 
  4205 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4206   [previously, this check worked only if the rewrite rule was unconditional]
  4207   Now rew can involve either definitions or equalities (either == or =).
  4208 
  4209 * case_tac provided for compatibility with HOL
  4210     (like the old excluded_middle_tac, but with subgoals swapped)
  4211 
  4212 
  4213 *** Internal programming interfaces ***
  4214 
  4215 * Pure: several new basic modules made available for general use, see
  4216 also src/Pure/README;
  4217 
  4218 * improved the theory data mechanism to support encapsulation (data
  4219 kind name replaced by private Object.kind, acting as authorization
  4220 key); new type-safe user interface via functor TheoryDataFun; generic
  4221 print_data function becomes basically useless;
  4222 
  4223 * removed global_names compatibility flag -- all theory declarations
  4224 are qualified by default;
  4225 
  4226 * module Pure/Syntax now offers quote / antiquote translation
  4227 functions (useful for Hoare logic etc. with implicit dependencies);
  4228 see HOL/ex/Antiquote for an example use;
  4229 
  4230 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4231 cterm -> thm;
  4232 
  4233 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4234 subgoal;
  4235 
  4236 * Display.print_goals function moved to Locale.print_goals;
  4237 
  4238 * standard print function for goals supports current_goals_markers
  4239 variable for marking begin of proof, end of proof, start of goal; the
  4240 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4241 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4242 for example;
  4243 
  4244 
  4245 
  4246 New in Isabelle98 (January 1998)
  4247 --------------------------------
  4248 
  4249 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4250 
  4251 * changed lexical syntax of terms / types: dots made part of long
  4252 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4253 
  4254 * simpset (and claset) reference variable replaced by functions
  4255 simpset / simpset_ref;
  4256 
  4257 * no longer supports theory aliases (via merge) and non-trivial
  4258 implicit merge of thms' signatures;
  4259 
  4260 * most internal names of constants changed due to qualified names;
  4261 
  4262 * changed Pure/Sequence interface (see Pure/seq.ML);
  4263 
  4264 
  4265 *** General Changes ***
  4266 
  4267 * hierachically structured name spaces (for consts, types, axms, thms
  4268 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4269 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4270 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4271 long_names for fully qualified output names; NOTE: ML programs
  4272 (special tactics, packages etc.) referring to internal names may have
  4273 to be adapted to cope with fully qualified names; in case of severe
  4274 backward campatibility problems try setting 'global_names' at compile
  4275 time to have enrything declared within a flat name space; one may also
  4276 fine tune name declarations in theories via the 'global' and 'local'
  4277 section;
  4278 
  4279 * reimplemented the implicit simpset and claset using the new anytype
  4280 data filed in signatures; references simpset:simpset ref etc. are
  4281 replaced by functions simpset:unit->simpset and
  4282 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4283 to patch your ML files accordingly;
  4284 
  4285 * HTML output now includes theory graph data for display with Java
  4286 applet or isatool browser; data generated automatically via isatool
  4287 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4288 
  4289 * defs may now be conditional; improved rewrite_goals_tac to handle
  4290 conditional equations;
  4291 
  4292 * defs now admits additional type arguments, using TYPE('a) syntax;
  4293 
  4294 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4295 creates a new theory node; implicit merge of thms' signatures is
  4296 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4297 transfer:theory->thm->thm in (rare) cases;
  4298 
  4299 * improved handling of draft signatures / theories; draft thms (and
  4300 ctyps, cterms) are automatically promoted to real ones;
  4301 
  4302 * slightly changed interfaces for oracles: admit many per theory, named
  4303 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4304 
  4305 * print_goals: optional output of const types (set show_consts and
  4306 show_types);
  4307 
  4308 * improved output of warnings (###) and errors (***);
  4309 
  4310 * subgoal_tac displays a warning if the new subgoal has type variables;
  4311 
  4312 * removed old README and Makefiles;
  4313 
  4314 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4315 
  4316 * removed obsolete init_pps and init_database;
  4317 
  4318 * deleted the obsolete tactical STATE, which was declared by
  4319     fun STATE tacfun st = tacfun st st;
  4320 
  4321 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4322 (which abbreviates $HOME);
  4323 
  4324 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4325 use isatool fixseq to adapt your ML programs (this works for fully
  4326 qualified references to the Sequence structure only!);
  4327 
  4328 * use_thy no longer requires writable current directory; it always
  4329 reloads .ML *and* .thy file, if either one is out of date;
  4330 
  4331 
  4332 *** Classical Reasoner ***
  4333 
  4334 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4335 tactics that use classical reasoning to simplify a subgoal without
  4336 splitting it into several subgoals;
  4337 
  4338 * Safe_tac: like safe_tac but uses the default claset;
  4339 
  4340 
  4341 *** Simplifier ***
  4342 
  4343 * added simplification meta rules:
  4344     (asm_)(full_)simplify: simpset -> thm -> thm;
  4345 
  4346 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4347 logics (again);
  4348 
  4349 * added prems argument to simplification procedures;
  4350 
  4351 * HOL, FOL, ZF: added infix function `addsplits':
  4352   instead of `<simpset> setloop (split_tac <thms>)'
  4353   you can simply write `<simpset> addsplits <thms>'
  4354 
  4355 
  4356 *** Syntax ***
  4357 
  4358 * TYPE('a) syntax for type reflection terms;
  4359 
  4360 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4361 
  4362 * pretty printer: changed order of mixfix annotation preference (again!);
  4363 
  4364 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4365 
  4366 
  4367 *** HOL ***
  4368 
  4369 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4370   with `addloop' of the simplifier to faciliate case splitting in premises.
  4371 
  4372 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4373 
  4374 * HOL/Auth: new protocol proofs including some for the Internet
  4375   protocol TLS;
  4376 
  4377 * HOL/Map: new theory of `maps' a la VDM;
  4378 
  4379 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4380 cancelling out common nat summands from =, <, <= (in)equalities, or
  4381 differences; simplification procedures nat_cancel_factor for
  4382 cancelling common factor from =, <, <= (in)equalities over natural
  4383 sums; nat_cancel contains both kinds of procedures, it is installed by
  4384 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4385 
  4386 * HOL/simplifier: terms of the form
  4387   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4388   are rewritten to
  4389   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4390   and those of the form
  4391   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4392   are rewritten to
  4393   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4394 
  4395 * HOL/datatype
  4396   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4397 
  4398   P(t_case f1 ... fn x) =
  4399      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4400         ...
  4401        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4402      )
  4403 
  4404   and a theorem `split_t_case_asm' of the form
  4405 
  4406   P(t_case f1 ... fn x) =
  4407     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4408         ...
  4409        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4410      )
  4411   which can be added to a simpset via `addsplits'. The existing theorems
  4412   expand_list_case and expand_option_case have been renamed to
  4413   split_list_case and split_option_case.
  4414 
  4415 * HOL/Arithmetic:
  4416   - `pred n' is automatically converted to `n-1'.
  4417     Users are strongly encouraged not to use `pred' any longer,
  4418     because it will disappear altogether at some point.
  4419   - Users are strongly encouraged to write "0 < n" rather than
  4420     "n ~= 0". Theorems and proof tools have been modified towards this
  4421     `standard'.
  4422 
  4423 * HOL/Lists:
  4424   the function "set_of_list" has been renamed "set" (and its theorems too);
  4425   the function "nth" now takes its arguments in the reverse order and
  4426   has acquired the infix notation "!" as in "xs!n".
  4427 
  4428 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4429 
  4430 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4431   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4432 
  4433 * HOL/record: extensible records with schematic structural subtyping
  4434 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4435 still lacks various theorems and concrete record syntax;
  4436 
  4437 
  4438 *** HOLCF ***
  4439 
  4440 * removed "axioms" and "generated by" sections;
  4441 
  4442 * replaced "ops" section by extended "consts" section, which is capable of
  4443   handling the continuous function space "->" directly;
  4444 
  4445 * domain package:
  4446   . proves theorems immediately and stores them in the theory,
  4447   . creates hierachical name space,
  4448   . now uses normal mixfix annotations (instead of cinfix...),
  4449   . minor changes to some names and values (for consistency),
  4450   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4451   . separator between mutual domain defs: changed "," to "and",
  4452   . improved handling of sort constraints;  now they have to
  4453     appear on the left-hand side of the equations only;
  4454 
  4455 * fixed LAM <x,y,zs>.b syntax;
  4456 
  4457 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4458 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4459 
  4460 
  4461 *** FOL and ZF ***
  4462 
  4463 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4464   with `addloop' of the simplifier to faciliate case splitting in premises.
  4465 
  4466 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4467 in HOL, they strip ALL and --> from proved theorems;
  4468 
  4469 
  4470 
  4471 New in Isabelle94-8 (May 1997)
  4472 ------------------------------
  4473 
  4474 *** General Changes ***
  4475 
  4476 * new utilities to build / run / maintain Isabelle etc. (in parts
  4477 still somewhat experimental); old Makefiles etc. still functional;
  4478 
  4479 * new 'Isabelle System Manual';
  4480 
  4481 * INSTALL text, together with ./configure and ./build scripts;
  4482 
  4483 * reimplemented type inference for greater efficiency, better error
  4484 messages and clean internal interface;
  4485 
  4486 * prlim command for dealing with lots of subgoals (an easier way of
  4487 setting goals_limit);
  4488 
  4489 
  4490 *** Syntax ***
  4491 
  4492 * supports alternative (named) syntax tables (parser and pretty
  4493 printer); internal interface is provided by add_modesyntax(_i);
  4494 
  4495 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4496 be used in conjunction with the Isabelle symbol font; uses the
  4497 "symbols" syntax table;
  4498 
  4499 * added token_translation interface (may translate name tokens in
  4500 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4501 the current print_mode); IMPORTANT: user print translation functions
  4502 are responsible for marking newly introduced bounds
  4503 (Syntax.mark_boundT);
  4504 
  4505 * token translations for modes "xterm" and "xterm_color" that display
  4506 names in bold, underline etc. or colors (which requires a color
  4507 version of xterm);
  4508 
  4509 * infixes may now be declared with names independent of their syntax;
  4510 
  4511 * added typed_print_translation (like print_translation, but may
  4512 access type of constant);
  4513 
  4514 
  4515 *** Classical Reasoner ***
  4516 
  4517 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4518 some limitations.  Blast_tac...
  4519   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4520   + ignores elimination rules that don't have the correct format
  4521         (the conclusion MUST be a formula variable)
  4522   + ignores types, which can make HOL proofs fail
  4523   + rules must not require higher-order unification, e.g. apply_type in ZF
  4524     [message "Function Var's argument not a bound variable" relates to this]
  4525   + its proof strategy is more general but can actually be slower
  4526 
  4527 * substitution with equality assumptions no longer permutes other
  4528 assumptions;
  4529 
  4530 * minor changes in semantics of addafter (now called addaltern); renamed
  4531 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4532 (and access functions for it);
  4533 
  4534 * improved combination of classical reasoner and simplifier:
  4535   + functions for handling clasimpsets
  4536   + improvement of addss: now the simplifier is called _after_ the
  4537     safe steps.
  4538   + safe variant of addss called addSss: uses safe simplifications
  4539     _during_ the safe steps. It is more complete as it allows multiple
  4540     instantiations of unknowns (e.g. with slow_tac).
  4541 
  4542 *** Simplifier ***
  4543 
  4544 * added interface for simplification procedures (functions that
  4545 produce *proven* rewrite rules on the fly, depending on current
  4546 redex);
  4547 
  4548 * ordering on terms as parameter (used for ordered rewriting);
  4549 
  4550 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4551 
  4552 * the solver is now split into a safe and an unsafe part.
  4553 This should be invisible for the normal user, except that the
  4554 functions setsolver and addsolver have been renamed to setSolver and
  4555 addSolver; added safe_asm_full_simp_tac;
  4556 
  4557 
  4558 *** HOL ***
  4559 
  4560 * a generic induction tactic `induct_tac' which works for all datatypes and
  4561 also for type `nat';
  4562 
  4563 * a generic case distinction tactic `exhaust_tac' which works for all
  4564 datatypes and also for type `nat';
  4565 
  4566 * each datatype comes with a function `size';
  4567 
  4568 * patterns in case expressions allow tuple patterns as arguments to
  4569 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4570 
  4571 * primrec now also works with type nat;
  4572 
  4573 * recdef: a new declaration form, allows general recursive functions to be
  4574 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4575 
  4576 * the constant for negation has been renamed from "not" to "Not" to
  4577 harmonize with FOL, ZF, LK, etc.;
  4578 
  4579 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4580 infinite lists;
  4581 
  4582 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4583 
  4584 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4585 problems in commutative rings, using axiomatic type classes for + and *;
  4586 
  4587 * more examples in HOL/MiniML and HOL/Auth;
  4588 
  4589 * more default rewrite rules for quantifiers, union/intersection;
  4590 
  4591 * a new constant `arbitrary == @x.False';
  4592 
  4593 * HOLCF/IOA replaces old HOL/IOA;
  4594 
  4595 * HOLCF changes: derived all rules and arities
  4596   + axiomatic type classes instead of classes
  4597   + typedef instead of faking type definitions
  4598   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4599   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4600   + eliminated the types void, one, tr
  4601   + use unit lift and bool lift (with translations) instead of one and tr
  4602   + eliminated blift from Lift3.thy (use Def instead of blift)
  4603   all eliminated rules are derived as theorems --> no visible changes ;
  4604 
  4605 
  4606 *** ZF ***
  4607 
  4608 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4609 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4610 as ZF_cs addSIs [equalityI];
  4611 
  4612 
  4613 
  4614 New in Isabelle94-7 (November 96)
  4615 ---------------------------------
  4616 
  4617 * allowing negative levels (as offsets) in prlev and choplev;
  4618 
  4619 * super-linear speedup for large simplifications;
  4620 
  4621 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4622 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4623 FAIL); can suppress it using the command Delsimps (ex_simps @
  4624 all_simps); De Morgan laws are also now included, by default;
  4625 
  4626 * improved printing of ==>  :  ~:
  4627 
  4628 * new object-logic "Sequents" adds linear logic, while replacing LK
  4629 and Modal (thanks to Sara Kalvala);
  4630 
  4631 * HOL/Auth: correctness proofs for authentication protocols;
  4632 
  4633 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4634 examples on HOL/Auth);
  4635 
  4636 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4637 the rewriter and classical reasoner simultaneously;
  4638 
  4639 * function uresult no longer returns theorems in "standard" format;
  4640 regain previous version by: val uresult = standard o uresult;
  4641 
  4642 
  4643 
  4644 New in Isabelle94-6
  4645 -------------------
  4646 
  4647 * oracles -- these establish an interface between Isabelle and trusted
  4648 external reasoners, which may deliver results as theorems;
  4649 
  4650 * proof objects (in particular record all uses of oracles);
  4651 
  4652 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4653 
  4654 * "constdefs" section in theory files;
  4655 
  4656 * "primrec" section (HOL) no longer requires names;
  4657 
  4658 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4659 
  4660 
  4661 
  4662 New in Isabelle94-5
  4663 -------------------
  4664 
  4665 * reduced space requirements;
  4666 
  4667 * automatic HTML generation from theories;
  4668 
  4669 * theory files no longer require "..." (quotes) around most types;
  4670 
  4671 * new examples, including two proofs of the Church-Rosser theorem;
  4672 
  4673 * non-curried (1994) version of HOL is no longer distributed;
  4674 
  4675 
  4676 
  4677 New in Isabelle94-4
  4678 -------------------
  4679 
  4680 * greatly reduced space requirements;
  4681 
  4682 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4683 
  4684 * searchable theorem database (see the section "Retrieving theorems" on
  4685 page 8 of the Reference Manual);
  4686 
  4687 * new examples, including Grabczewski's monumental case study of the
  4688 Axiom of Choice;
  4689 
  4690 * The previous version of HOL renamed to Old_HOL;
  4691 
  4692 * The new version of HOL (previously called CHOL) uses a curried syntax
  4693 for functions.  Application looks like f a b instead of f(a,b);
  4694 
  4695 * Mutually recursive inductive definitions finally work in HOL;
  4696 
  4697 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4698 translates to the operator "split";
  4699 
  4700 
  4701 
  4702 New in Isabelle94-3
  4703 -------------------
  4704 
  4705 * new infix operator, addss, allowing the classical reasoner to
  4706 perform simplification at each step of its search.  Example:
  4707         fast_tac (cs addss ss)
  4708 
  4709 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4710 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4711 look like (a,b) instead of <a,b>;
  4712 
  4713 * PLEASE NOTE: CHOL will eventually replace HOL!
  4714 
  4715 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4716 It translates to the operator "split".  A new theory of integers is available;
  4717 
  4718 * In ZF, integer numerals now denote two's-complement binary integers.
  4719 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4720 
  4721 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4722 of the Axiom of Choice;
  4723 
  4724 
  4725 
  4726 New in Isabelle94-2
  4727 -------------------
  4728 
  4729 * Significantly faster resolution;
  4730 
  4731 * the different sections in a .thy file can now be mixed and repeated
  4732 freely;
  4733 
  4734 * Database of theorems for FOL, HOL and ZF.  New
  4735 commands including qed, qed_goal and bind_thm store theorems in the database.
  4736 
  4737 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4738 a given theory (thms_of), or find out what theory a theorem was proved in
  4739 (theory_of_thm);
  4740 
  4741 * Bugs fixed in the inductive definition and datatype packages;
  4742 
  4743 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4744 and HOL_dup_cs obsolete;
  4745 
  4746 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4747 have been removed;
  4748 
  4749 * Simpler definition of function space in ZF;
  4750 
  4751 * new results about cardinal and ordinal arithmetic in ZF;
  4752 
  4753 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4754 types;
  4755 
  4756 
  4757 $Id$