NEWS
author huffman
Mon May 14 20:14:31 2007 +0200 (2007-05-14)
changeset 22972 3e96b98d37c6
parent 22971 a6812b6a36a5
child 22997 d4f3b015b50b
permissions -rw-r--r--
generalized sgn function to work on any real normed vector space
     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 * case expressions and primrec: missing cases now mapped to "undefined"
   534 instead of "arbitrary"
   535 
   536 * new constant "undefined" with axiom "undefined x = undefined"
   537 
   538 * new class "default" with associated constant "default"
   539 
   540 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   541     when generating code.
   542 
   543 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   544     when generating code.
   545 
   546 * Library/Commutative_Ring.thy: switched from recdef to function package;
   547     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   548 
   549 * Some steps towards more uniform lattice theory development in HOL.
   550 
   551     constants "meet" and "join" now named "inf" and "sup"
   552     constant "Meet" now named "Inf"
   553 
   554     classes "meet_semilorder" and "join_semilorder" now named
   555       "lower_semilattice" and "upper_semilattice"
   556     class "lorder" now named "lattice"
   557     class "comp_lat" now named "complete_lattice"
   558 
   559     Instantiation of lattice classes allows explicit definitions
   560     for "inf" and "sup" operations.
   561 
   562   INCOMPATIBILITY. Theorem renames:
   563 
   564     meet_left_le            ~> inf_le1
   565     meet_right_le           ~> inf_le2
   566     join_left_le            ~> sup_ge1
   567     join_right_le           ~> sup_ge2
   568     meet_join_le            ~> inf_sup_ord
   569     le_meetI                ~> le_infI
   570     join_leI                ~> le_supI
   571     le_meet                 ~> le_inf_iff
   572     le_join                 ~> ge_sup_conv
   573     meet_idempotent         ~> inf_idem
   574     join_idempotent         ~> sup_idem
   575     meet_comm               ~> inf_commute
   576     join_comm               ~> sup_commute
   577     meet_leI1               ~> le_infI1
   578     meet_leI2               ~> le_infI2
   579     le_joinI1               ~> le_supI1
   580     le_joinI2               ~> le_supI2
   581     meet_assoc              ~> inf_assoc
   582     join_assoc              ~> sup_assoc
   583     meet_left_comm          ~> inf_left_commute
   584     meet_left_idempotent    ~> inf_left_idem
   585     join_left_comm          ~> sup_left_commute
   586     join_left_idempotent    ~> sup_left_idem
   587     meet_aci                ~> inf_aci
   588     join_aci                ~> sup_aci
   589     le_def_meet             ~> le_iff_inf
   590     le_def_join             ~> le_iff_sup
   591     join_absorp2            ~> sup_absorb2
   592     join_absorp1            ~> sup_absorb1
   593     meet_absorp1            ~> inf_absorb1
   594     meet_absorp2            ~> inf_absorb2
   595     meet_join_absorp        ~> inf_sup_absorb
   596     join_meet_absorp        ~> sup_inf_absorb
   597     distrib_join_le         ~> distrib_sup_le
   598     distrib_meet_le         ~> distrib_inf_le
   599 
   600     add_meet_distrib_left   ~> add_inf_distrib_left
   601     add_join_distrib_left   ~> add_sup_distrib_left
   602     is_join_neg_meet        ~> is_join_neg_inf
   603     is_meet_neg_join        ~> is_meet_neg_sup
   604     add_meet_distrib_right  ~> add_inf_distrib_right
   605     add_join_distrib_right  ~> add_sup_distrib_right
   606     add_meet_join_distribs  ~> add_sup_inf_distribs
   607     join_eq_neg_meet        ~> sup_eq_neg_inf
   608     meet_eq_neg_join        ~> inf_eq_neg_sup
   609     add_eq_meet_join        ~> add_eq_inf_sup
   610     meet_0_imp_0            ~> inf_0_imp_0
   611     join_0_imp_0            ~> sup_0_imp_0
   612     meet_0_eq_0             ~> inf_0_eq_0
   613     join_0_eq_0             ~> sup_0_eq_0
   614     neg_meet_eq_join        ~> neg_inf_eq_sup
   615     neg_join_eq_meet        ~> neg_sup_eq_inf
   616     join_eq_if              ~> sup_eq_if
   617 
   618     mono_meet               ~> mono_inf
   619     mono_join               ~> mono_sup
   620     meet_bool_eq            ~> inf_bool_eq
   621     join_bool_eq            ~> sup_bool_eq
   622     meet_fun_eq             ~> inf_fun_eq
   623     join_fun_eq             ~> sup_fun_eq
   624     meet_set_eq             ~> inf_set_eq
   625     join_set_eq             ~> sup_set_eq
   626     meet1_iff               ~> inf1_iff
   627     meet2_iff               ~> inf2_iff
   628     meet1I                  ~> inf1I
   629     meet2I                  ~> inf2I
   630     meet1D1                 ~> inf1D1
   631     meet2D1                 ~> inf2D1
   632     meet1D2                 ~> inf1D2
   633     meet2D2                 ~> inf2D2
   634     meet1E                  ~> inf1E
   635     meet2E                  ~> inf2E
   636     join1_iff               ~> sup1_iff
   637     join2_iff               ~> sup2_iff
   638     join1I1                 ~> sup1I1
   639     join2I1                 ~> sup2I1
   640     join1I1                 ~> sup1I1
   641     join2I2                 ~> sup1I2
   642     join1CI                 ~> sup1CI
   643     join2CI                 ~> sup2CI
   644     join1E                  ~> sup1E
   645     join2E                  ~> sup2E
   646 
   647     is_meet_Meet            ~> is_meet_Inf
   648     Meet_bool_def           ~> Inf_bool_def
   649     Meet_fun_def            ~> Inf_fun_def
   650     Meet_greatest           ~> Inf_greatest
   651     Meet_lower              ~> Inf_lower
   652     Meet_set_def            ~> Inf_set_def
   653 
   654     listsp_meetI            ~> listsp_infI
   655     listsp_meet_eq          ~> listsp_inf_eq
   656 
   657     meet_min                ~> inf_min
   658     join_max                ~> sup_max
   659 
   660 * Classes "order" and "linorder": facts "refl", "trans" and
   661 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   662 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   663 
   664 * Classes "order" and "linorder": 
   665 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   666 proofs changed.
   667 
   668 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   669 INCOMPATIBILITY.
   670 
   671 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   672 INCOMPATIBILITY.
   673 
   674 * Added syntactic class "size"; overloaded constant "size" now has
   675 type "'a::size ==> bool"
   676 
   677 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   678 dvd" to "Divides.div", "Divides.mod" and "Divides.dvd". INCOMPATIBILITY.
   679 
   680 * Added method "lexicographic_order" automatically synthesizes
   681 termination relations as lexicographic combinations of size measures
   682 -- 'function' package.
   683 
   684 * HOL/records: generalised field-update to take a function on the
   685 field rather than the new value: r(|A := x|) is translated to A_update
   686 (K x) r The K-combinator that is internally used is called K_record.
   687 INCOMPATIBILITY: Usage of the plain update functions has to be
   688 adapted.
   689  
   690 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   691 0 * x = 0, which are required for a semiring.  Richer structures do
   692 not inherit from semiring_0 anymore, because this property is a
   693 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   694 semiring_0, there is more to prove, but this is mostly trivial.
   695 
   696 * axclass "recpower" was generalized to arbitrary monoids, not just
   697 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   698 commutativity or a semiring property, add the corresponding classes.
   699 
   700 * Unified locale partial_order with class definition (cf. theory
   701 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   702 
   703 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   704 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   705 Isar level, use abbreviations instead.
   706 
   707 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   708 rarely occuring name references (e.g. ``List.op mem.simps'') require
   709 renaming (e.g. ``List.memberl.simps'').
   710 
   711 * Renamed constants "0" to "HOL.zero" and "1" to "HOL.one".
   712 INCOMPATIBILITY.
   713 
   714 * Added theory Code_Generator providing class 'eq', allowing for code
   715 generation with polymorphic equality.
   716 
   717 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   718 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   719 significant changes for setting up numeral syntax for types:
   720 
   721   - new constants Numeral.pred and Numeral.succ instead
   722       of former Numeral.bin_pred and Numeral.bin_succ.
   723   - Use integer operations instead of bin_add, bin_mult and so on.
   724   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   725   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   726 
   727 See HOL/Integ/IntArith.thy for an example setup.
   728 
   729 * New top level command 'normal_form' computes the normal form of a
   730 term that may contain free variables. For example ``normal_form
   731 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   732 suitable for heavy-duty computations because the functions are
   733 compiled to ML first.
   734 
   735 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   736 25 like -->); output depends on the "iff" print_mode, the default is
   737 "A = B" (with priority 50).
   738 
   739 * Renamed constants in HOL.thy and Orderings.thy:
   740     op +   ~> HOL.plus
   741     op -   ~> HOL.minus
   742     uminus ~> HOL.uminus
   743     op *   ~> HOL.times
   744     op <   ~> Orderings.less
   745     op <=  ~> Orderings.less_eq
   746 
   747 Adaptions may be required in the following cases:
   748 
   749 a) User-defined constants using any of the names "plus", "minus", "times",
   750 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   751 may go wrong.
   752 INCOMPATIBILITY: use more specific names.
   753 
   754 b) Variables named "plus", "minus", "times", "less", "less_eq"
   755 INCOMPATIBILITY: use more specific names.
   756 
   757 c) Permutative equations (e.g. "a + b = b + a")
   758 Since the change of names also changes the order of terms, permutative
   759 rewrite rules may get applied in a different order. Experience shows that
   760 this is rarely the case (only two adaptions in the whole Isabelle
   761 distribution).
   762 INCOMPATIBILITY: rewrite proofs
   763 
   764 d) ML code directly refering to constant names
   765 This in general only affects hand-written proof tactics, simprocs and so on.
   766 INCOMPATIBILITY: grep your sourcecode and replace names.
   767 
   768 * Relations less (<) and less_eq (<=) are also available on type bool.
   769 Modified syntax to disallow nesting without explicit parentheses,
   770 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   771 
   772 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   773 
   774 * Relation composition operator "op O" now has precedence 75 and binds
   775 stronger than union and intersection. INCOMPATIBILITY.
   776 
   777 * The old set interval syntax "{m..n(}" (and relatives) has been
   778 removed.  Use "{m..<n}" (and relatives) instead.
   779 
   780 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   781 "t = s" to False (by simproc "neq_simproc").  For backward
   782 compatibility this can be disabled by ML "reset use_neq_simproc".
   783 
   784 * "m dvd n" where m and n are numbers is evaluated to True/False by
   785 simp.
   786 
   787 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   788 
   789 * Theorem setsum_mult renamed to setsum_right_distrib.
   790 
   791 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   792 ``rule'' method.
   793 
   794 * Reimplemented methods ``sat'' and ``satx'', with several
   795 improvements: goals no longer need to be stated as "<prems> ==>
   796 False", equivalences (i.e. "=" on type bool) are handled, variable
   797 names of the form "lit_<n>" are no longer reserved, significant
   798 speedup.
   799 
   800 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   801 zChaff is still supported as well.
   802 
   803 * 'inductive' and 'datatype': provide projections of mutual rules,
   804 bundled as foo_bar.inducts;
   805 
   806 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   807 Library.
   808 
   809 * Library: moved theory Accessible_Part to main HOL.
   810 
   811 * Library: added theory Coinductive_List of potentially infinite lists
   812 as greatest fixed-point.
   813 
   814 * Library: added theory AssocList which implements (finite) maps as
   815 association lists.
   816 
   817 * Added proof method ``evaluation'' for efficiently solving a goal
   818 (i.e. a boolean expression) by compiling it to ML. The goal is
   819 "proved" (via an oracle) if it evaluates to True.
   820 
   821 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   822 also when invoked by the simplifier.  This results in the simplifier
   823 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   824 fast_arith_split_limit to 0 to obtain the old behavior.
   825 
   826 * Support for hex (0x20) and binary (0b1001) numerals.
   827 
   828 * New method: reify eqs (t), where eqs are equations for an
   829 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   830 parameter, computes a term s::'b and a list xs::'a list and proves the
   831 theorem I xs s = t. This is also known as reification or quoting. The
   832 resulting theorem is applied to the subgoal to substitute t with I xs
   833 s.  If t is omitted, the subgoal itself is reified.
   834 
   835 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   836 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   837 where f is supposed to be a computable function (in the sense of code
   838 generattion). The method uses reify to compute s and xs as above then
   839 applies corr_thm and uses normalization by evaluation to "prove" f s =
   840 r and finally gets the theorem t = r, which is again applied to the
   841 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   842 
   843 * Reflection: Automatic refification now handels binding, an example
   844 is available in HOL/ex/ReflectionEx.thy
   845 
   846 
   847 *** HOL-Algebra ***
   848 
   849 * Formalisation of ideals and the quotient construction over rings.
   850 
   851 * Order and lattice theory no longer based on records.
   852 INCOMPATIBILITY.
   853 
   854 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   855 greatest_closed.  INCOMPATIBILITY.
   856 
   857 * Method algebra is now set up via an attribute.  For examples see
   858 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   859 of algebraic structures.
   860 
   861 * Renamed theory CRing to Ring.
   862 
   863 
   864 *** HOL-Complex ***
   865 
   866 * Theory Real: new method ferrack implements quantifier elimination
   867 for linear arithmetic over the reals. The quantifier elimination
   868 feature is used only for decision, for compatibility with arith. This
   869 means a goal is either solved or left unchanged, no simplification.
   870 
   871 * Hyperreal: Functions root and sqrt are now defined on negative real
   872 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
   873 Nonnegativity side conditions have been removed from many lemmas, so
   874 that more subgoals may now be solved by simplification; potential
   875 INCOMPATIBILITY.
   876 
   877 * Real: New axiomatic classes formalize real normed vector spaces and
   878 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   879 and norm :: 'a => real.
   880 
   881 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   882 from reals into other types. The overloaded constant Reals :: 'a set
   883 is now defined as range of_real; potential INCOMPATIBILITY.
   884 
   885 * Hyperreal: Several constants that previously worked only for the
   886 reals have been generalized, so they now work over arbitrary vector
   887 spaces. Type annotations may need to be added in some cases; potential
   888 INCOMPATIBILITY.
   889 
   890   Infinitesimal  :: ('a::real_normed_vector) star set
   891   HFinite        :: ('a::real_normed_vector) star set
   892   HInfinite      :: ('a::real_normed_vector) star set
   893   approx         :: ('a::real_normed_vector) star => 'a star => bool
   894   monad          :: ('a::real_normed_vector) star => 'a star set
   895   galaxy         :: ('a::real_normed_vector) star => 'a star set
   896   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
   897   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   898   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   899   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   900   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   901   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   902   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   903   sgn            :: 'a::real_normed_vector => 'a
   904 
   905 * Complex: Some complex-specific constants are now abbreviations for
   906 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   907 hnorm.  Other constants have been entirely removed in favor of the
   908 polymorphic versions (INCOMPATIBILITY):
   909 
   910   approx        <-- capprox
   911   HFinite       <-- CFinite
   912   HInfinite     <-- CInfinite
   913   Infinitesimal <-- CInfinitesimal
   914   monad         <-- cmonad
   915   galaxy        <-- cgalaxy
   916   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   917   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   918   (ns)deriv     <-- (ns)cderiv
   919 
   920 
   921 *** ML ***
   922 
   923 * Context data interfaces (Theory/Proof/GenericDataFun): removed
   924 name/print, uninitialized data defaults to ad-hoc copy of empty value,
   925 init only required for impure data.  INCOMPATIBILITY: empty really
   926 need to be empty (no dependencies on theory content!)
   927 
   928 * ML within Isar: antiquotations allow to embed statically-checked
   929 formal entities in the source, referring to the context available at
   930 compile-time.  For example:
   931 
   932 ML {* @{typ "'a => 'b"} *}
   933 ML {* @{term "%x. x"} *}
   934 ML {* @{prop "x == y"} *}
   935 ML {* @{ctyp "'a => 'b"} *}
   936 ML {* @{cterm "%x. x"} *}
   937 ML {* @{cprop "x == y"} *}
   938 ML {* @{thm asm_rl} *}
   939 ML {* @{thms asm_rl} *}
   940 ML {* @{const_name c} *}
   941 ML {* @{const_syntax c} *}
   942 ML {* @{context} *}
   943 ML {* @{theory} *}
   944 ML {* @{theory Pure} *}
   945 ML {* @{simpset} *}
   946 ML {* @{claset} *}
   947 ML {* @{clasimpset} *}
   948 
   949 The same works for sources being ``used'' within an Isar context.
   950 
   951 * ML in Isar: improved error reporting; extra verbosity with
   952 Toplevel.debug enabled.
   953 
   954 * Pure/library:
   955 
   956   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   957   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   958 
   959 The semantics of "burrow" is: "take a function with *simulatanously*
   960 transforms a list of value, and apply it *simulatanously* to a list of
   961 list of values of the appropriate type". Compare this with "map" which
   962 would *not* apply its argument function simulatanously but in
   963 sequence; "fold_burrow" has an additional context.
   964 
   965 * Pure/library: functions map2 and fold2 with curried syntax for
   966 simultanous mapping and folding:
   967 
   968     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   969     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   970 
   971 * Pure/library: indexed lists - some functions in the Isabelle library
   972 treating lists over 'a as finite mappings from [0...n] to 'a have been
   973 given more convenient names and signatures reminiscent of similar
   974 functions for alists, tables, etc:
   975 
   976   val nth: 'a list -> int -> 'a 
   977   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   978   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   979 
   980 Note that fold_index starts counting at index 0, not 1 like foldln
   981 used to.
   982 
   983 * Pure/library: added general ``divide_and_conquer'' combinator on
   984 lists.
   985 
   986 * Pure/General/table.ML: the join operations now works via exceptions
   987 DUP/SAME instead of type option.  This is simpler in simple cases, and
   988 admits slightly more efficient complex applications.
   989 
   990 * Pure: datatype Context.generic joins theory/Proof.context and
   991 provides some facilities for code that works in either kind of
   992 context, notably GenericDataFun for uniform theory and proof data.
   993 
   994 * Pure: 'advanced' translation functions (parse_translation etc.) now
   995 use Context.generic instead of just theory.
   996 
   997 * Pure: simplified internal attribute type, which is now always
   998 Context.generic * thm -> Context.generic * thm.  Global (theory)
   999 vs. local (Proof.context) attributes have been discontinued, while
  1000 minimizing code duplication.  Thm.rule_attribute and
  1001 Thm.declaration_attribute build canonical attributes; see also
  1002 structure Context for further operations on Context.generic, notably
  1003 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1004 declarations and definitions.
  1005 
  1006 * Pure/kernel: consts certification ignores sort constraints given in
  1007 signature declarations.  (This information is not relevant to the
  1008 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1009 potential INCOMPATIBILITY.
  1010 
  1011 * Pure: axiomatic type classes are now purely definitional, with
  1012 explicit proofs of class axioms and super class relations performed
  1013 internally.  See Pure/axclass.ML for the main internal interfaces --
  1014 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1015 AxClass.axiomatize_class/classrel/arity supercede
  1016 Sign.add_classes/classrel/arities.
  1017 
  1018 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1019 global/local versions on theory vs. Proof.context have been
  1020 discontinued; Attrib.syntax and Method.syntax have been adapted
  1021 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1022 attributes, methods, etc.
  1023 
  1024 * Pure: several functions of signature "... -> theory -> theory * ..."
  1025 have been reoriented to "... -> theory -> ... * theory" in order to
  1026 allow natural usage in combination with the ||>, ||>>, |-> and
  1027 fold_map combinators.
  1028 
  1029 * Pure: official theorem names (closed derivations) and additional
  1030 comments (tags) are now strictly separate.  Name hints -- which are
  1031 maintained as tags -- may be attached any time without affecting the
  1032 derivation.
  1033 
  1034 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1035 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1036 achieve the old behaviour.
  1037 
  1038 * Pure: the "Goal" constant is now called "prop", supporting a
  1039 slightly more general idea of ``protecting'' meta-level rule
  1040 statements.
  1041 
  1042 * Pure: Logic.(un)varify only works in a global context, which is now
  1043 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1044 Logic.legacy_(un)varify as temporary workaround.
  1045 
  1046 * Pure: structure Name provides scalable operations for generating
  1047 internal variable names, notably Name.variants etc.  This replaces
  1048 some popular functions from term.ML:
  1049 
  1050   Term.variant		->  Name.variant
  1051   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1052   Term.invent_names	->  Name.invent_list
  1053 
  1054 Note that low-level renaming rarely occurs in new code -- operations
  1055 from structure Variable are used instead (see below).
  1056 
  1057 * Pure: structure Variable provides fundamental operations for proper
  1058 treatment of fixed/schematic variables in a context.  For example,
  1059 Variable.import introduces fixes for schematics of given facts and
  1060 Variable.export reverses the effect (up to renaming) -- this replaces
  1061 various freeze_thaw operations.
  1062 
  1063 * Pure: structure Goal provides simple interfaces for
  1064 init/conclude/finish and tactical prove operations (replacing former
  1065 Tactic.prove).  Goal.prove is the canonical way to prove results
  1066 within a given context; Goal.prove_global is a degraded version for
  1067 theory level goals, including a global Drule.standard.  Note that
  1068 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1069 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1070 in a locale context).
  1071 
  1072 * Isar: simplified treatment of user-level errors, using exception
  1073 ERROR of string uniformly.  Function error now merely raises ERROR,
  1074 without any side effect on output channels.  The Isar toplevel takes
  1075 care of proper display of ERROR exceptions.  ML code may use plain
  1076 handle/can/try; cat_error may be used to concatenate errors like this:
  1077 
  1078   ... handle ERROR msg => cat_error msg "..."
  1079 
  1080 Toplevel ML code (run directly or through the Isar toplevel) may be
  1081 embedded into the Isar toplevel with exception display/debug like
  1082 this:
  1083 
  1084   Isar.toplevel (fn () => ...)
  1085 
  1086 INCOMPATIBILITY, removed special transform_error facilities, removed
  1087 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1088 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1089 -- use plain ERROR instead.
  1090 
  1091 * Isar: theory setup now has type (theory -> theory), instead of a
  1092 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1093 
  1094 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1095 subject to ProofContext.debug/verbose flags.
  1096 
  1097 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1098 theory before entering a proof state.  Transactions now always see a
  1099 quasi-functional intermediate checkpoint, both in interactive and
  1100 batch mode.
  1101 
  1102 * Simplifier: the simpset of a running simplification process now
  1103 contains a proof context (cf. Simplifier.the_context), which is the
  1104 very context that the initial simpset has been retrieved from (by
  1105 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1106 (solver, looper etc.) may depend on arbitrary proof data.
  1107 
  1108 * Simplifier.inherit_context inherits the proof context (plus the
  1109 local bounds) of the current simplification process; any simproc
  1110 etc. that calls the Simplifier recursively should do this!  Removed
  1111 former Simplifier.inherit_bounds, which is already included here --
  1112 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1113 specify an explicit context using Simplifier.context/theory_context.
  1114 
  1115 * Simplifier/Classical Reasoner: more abstract interfaces
  1116 change_simpset/claset for modifying the simpset/claset reference of a
  1117 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1118 INCOMPATIBILITY.
  1119 
  1120 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1121 "Trueprop" etc.
  1122 
  1123 
  1124 *** System ***
  1125 
  1126 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1127 locations -- now includes the Isabelle version identifier as well.
  1128 This simplifies use of multiple Isabelle installations.
  1129 
  1130 * isabelle-process: option -S (secure mode) disables some critical
  1131 operations, notably runtime compilation and evaluation of ML source
  1132 code.
  1133 
  1134 
  1135 New in Isabelle2005 (October 2005)
  1136 ----------------------------------
  1137 
  1138 *** General ***
  1139 
  1140 * Theory headers: the new header syntax for Isar theories is
  1141 
  1142   theory <name>
  1143   imports <theory1> ... <theoryN>
  1144   uses <file1> ... <fileM>
  1145   begin
  1146 
  1147 where the 'uses' part is optional.  The previous syntax
  1148 
  1149   theory <name> = <theory1> + ... + <theoryN>:
  1150 
  1151 will disappear in the next release.  Use isatool fixheaders to convert
  1152 existing theory files.  Note that there is no change in ancient
  1153 non-Isar theories now, but these will disappear soon.
  1154 
  1155 * Theory loader: parent theories can now also be referred to via
  1156 relative and absolute paths.
  1157 
  1158 * Command 'find_theorems' searches for a list of criteria instead of a
  1159 list of constants. Known criteria are: intro, elim, dest, name:string,
  1160 simp:term, and any term. Criteria can be preceded by '-' to select
  1161 theorems that do not match. Intro, elim, dest select theorems that
  1162 match the current goal, name:s selects theorems whose fully qualified
  1163 name contain s, and simp:term selects all simplification rules whose
  1164 lhs match term.  Any other term is interpreted as pattern and selects
  1165 all theorems matching the pattern. Available in ProofGeneral under
  1166 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1167 
  1168   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1169 
  1170 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1171 matching the current goal as introduction rule and not having "HOL."
  1172 in their name (i.e. not being defined in theory HOL).
  1173 
  1174 * Command 'thms_containing' has been discontinued in favour of
  1175 'find_theorems'; INCOMPATIBILITY.
  1176 
  1177 * Communication with Proof General is now 8bit clean, which means that
  1178 Unicode text in UTF-8 encoding may be used within theory texts (both
  1179 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1180 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1181 
  1182   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1183   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1184 
  1185 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1186 Classical Reasoner.  Typical big applications run around 2 times
  1187 faster.
  1188 
  1189 
  1190 *** Document preparation ***
  1191 
  1192 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1193 of raw sources.  Only those symbols that do not require additional
  1194 LaTeX packages (depending on comments in isabellesym.sty) are
  1195 displayed properly, everything else is left verbatim.  isatool display
  1196 and isatool print are used as front ends (these are subject to the
  1197 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1198 
  1199 * Command tags control specific markup of certain regions of text,
  1200 notably folding and hiding.  Predefined tags include "theory" (for
  1201 theory begin and end), "proof" for proof commands, and "ML" for
  1202 commands involving ML code; the additional tags "visible" and
  1203 "invisible" are unused by default.  Users may give explicit tag
  1204 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1205 interpretation of tags is determined by the LaTeX job during document
  1206 preparation: see option -V of isatool usedir, or options -n and -t of
  1207 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1208 \isadroptag.
  1209 
  1210 Several document versions may be produced at the same time via isatool
  1211 usedir (the generated index.html will link all of them).  Typical
  1212 specifications include ''-V document=theory,proof,ML'' to present
  1213 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1214 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1215 these parts without any formal replacement text.  The Isabelle site
  1216 default settings produce ''document'' and ''outline'' versions as
  1217 specified above.
  1218 
  1219 * Several new antiquotations:
  1220 
  1221   @{term_type term} prints a term with its type annotated;
  1222 
  1223   @{typeof term} prints the type of a term;
  1224 
  1225   @{const const} is the same as @{term const}, but checks that the
  1226   argument is a known logical constant;
  1227 
  1228   @{term_style style term} and @{thm_style style thm} print a term or
  1229   theorem applying a "style" to it
  1230 
  1231   @{ML text}
  1232 
  1233 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1234 definitions, equations, inequations etc., 'concl' printing only the
  1235 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1236 to print the specified premise.  TermStyle.add_style provides an ML
  1237 interface for introducing further styles.  See also the "LaTeX Sugar"
  1238 document practical applications.  The ML antiquotation prints
  1239 type-checked ML expressions verbatim.
  1240 
  1241 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1242 and 'text' support optional locale specification '(in loc)', which
  1243 specifies the default context for interpreting antiquotations.  For
  1244 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1245 
  1246 * Option 'locale=NAME' of antiquotations specifies an alternative
  1247 context interpreting the subsequent argument.  For example: @{thm
  1248 [locale=lattice] inf_assoc}.
  1249 
  1250 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1251 a proof context.
  1252 
  1253 * Proper output of antiquotations for theory commands involving a
  1254 proof context (such as 'locale' or 'theorem (in loc) ...').
  1255 
  1256 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1257 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1258 
  1259 * isatool usedir: new option -C (default true) controls whether option
  1260 -D should include a copy of the original document directory; -C false
  1261 prevents unwanted effects such as copying of administrative CVS data.
  1262 
  1263 
  1264 *** Pure ***
  1265 
  1266 * Considerably improved version of 'constdefs' command.  Now performs
  1267 automatic type-inference of declared constants; additional support for
  1268 local structure declarations (cf. locales and HOL records), see also
  1269 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1270 sequential dependencies of definitions within a single 'constdefs'
  1271 section; moreover, the declared name needs to be an identifier.  If
  1272 all fails, consider to fall back on 'consts' and 'defs' separately.
  1273 
  1274 * Improved indexed syntax and implicit structures.  First of all,
  1275 indexed syntax provides a notational device for subscripted
  1276 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1277 expressions.  Secondly, in a local context with structure
  1278 declarations, number indexes \<^sub>n or the empty index (default
  1279 number 1) refer to a certain fixed variable implicitly; option
  1280 show_structs controls printing of implicit structures.  Typical
  1281 applications of these concepts involve record types and locales.
  1282 
  1283 * New command 'no_syntax' removes grammar declarations (and
  1284 translations) resulting from the given syntax specification, which is
  1285 interpreted in the same manner as for the 'syntax' command.
  1286 
  1287 * 'Advanced' translation functions (parse_translation etc.) may depend
  1288 on the signature of the theory context being presently used for
  1289 parsing/printing, see also isar-ref manual.
  1290 
  1291 * Improved 'oracle' command provides a type-safe interface to turn an
  1292 ML expression of type theory -> T -> term into a primitive rule of
  1293 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1294 is already included here); see also FOL/ex/IffExample.thy;
  1295 INCOMPATIBILITY.
  1296 
  1297 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1298 before); "cI" is no longer bound, use "c.intro" instead.
  1299 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1300 axclasses vs. locales.
  1301 
  1302 * Improved internal renaming of symbolic identifiers -- attach primes
  1303 instead of base 26 numbers.
  1304 
  1305 * New flag show_question_marks controls printing of leading question
  1306 marks in schematic variable names.
  1307 
  1308 * In schematic variable names, *any* symbol following \<^isub> or
  1309 \<^isup> is now treated as part of the base name.  For example, the
  1310 following works without printing of awkward ".0" indexes:
  1311 
  1312   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1313     by simp
  1314 
  1315 * Inner syntax includes (*(*nested*) comments*).
  1316 
  1317 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1318 annotations as "(00...)".
  1319 
  1320 * Clear separation of logical types and nonterminals, where the latter
  1321 may only occur in 'syntax' specifications or type abbreviations.
  1322 Before that distinction was only partially implemented via type class
  1323 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1324 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1325 exotic syntax specifications may require further adaption
  1326 (e.g. Cube/Cube.thy).
  1327 
  1328 * Removed obsolete type class "logic", use the top sort {} instead.
  1329 Note that non-logical types should be declared as 'nonterminals'
  1330 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1331 specifications.
  1332 
  1333 * Attributes 'induct' and 'cases': type or set names may now be
  1334 locally fixed variables as well.
  1335 
  1336 * Simplifier: can now control the depth to which conditional rewriting
  1337 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1338 Limit.
  1339 
  1340 * Simplifier: simplification procedures may now take the current
  1341 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1342 interface), which is very useful for calling the Simplifier
  1343 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1344 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1345 low-level mk_simproc no longer applies Logic.varify internally, to
  1346 allow for use in a context of fixed variables.
  1347 
  1348 * thin_tac now works even if the assumption being deleted contains !!
  1349 or ==>.  More generally, erule now works even if the major premise of
  1350 the elimination rule contains !! or ==>.
  1351 
  1352 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1353 
  1354 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1355 from Pure, which contains all common declarations already.  Both
  1356 theories are defined via plain Isabelle/Isar .thy files.
  1357 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1358 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1359 use isatool fixcpure to adapt your theory and ML sources.
  1360 
  1361 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1362 selections of theorems in named facts via index ranges.
  1363 
  1364 * 'print_theorems': in theory mode, really print the difference
  1365 wrt. the last state (works for interactive theory development only),
  1366 in proof mode print all local facts (cf. 'print_facts');
  1367 
  1368 * 'hide': option '(open)' hides only base names.
  1369 
  1370 * More efficient treatment of intermediate checkpoints in interactive
  1371 theory development.
  1372 
  1373 * Code generator is now invoked via code_module (incremental code
  1374 generation) and code_library (modular code generation, ML structures
  1375 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1376 must be quoted when used as identifiers.
  1377 
  1378 * New 'value' command for reading, evaluating and printing terms using
  1379 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1380 quoted when used as identifier.
  1381 
  1382 
  1383 *** Locales ***
  1384 
  1385 * New commands for the interpretation of locale expressions in
  1386 theories (1), locales (2) and proof contexts (3).  These generate
  1387 proof obligations from the expression specification.  After the
  1388 obligations have been discharged, theorems of the expression are added
  1389 to the theory, target locale or proof context.  The synopsis of the
  1390 commands is a follows:
  1391 
  1392   (1) interpretation expr inst
  1393   (2) interpretation target < expr
  1394   (3) interpret expr inst
  1395 
  1396 Interpretation in theories and proof contexts require a parameter
  1397 instantiation of terms from the current context.  This is applied to
  1398 specifications and theorems of the interpreted expression.
  1399 Interpretation in locales only permits parameter renaming through the
  1400 locale expression.  Interpretation is smart in that interpretations
  1401 that are active already do not occur in proof obligations, neither are
  1402 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1403 inspect active interpretations of a particular locale.  For details,
  1404 see the Isar Reference manual.  Examples can be found in
  1405 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1406 
  1407 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1408 'interpret' instead.
  1409 
  1410 * New context element 'constrains' for adding type constraints to
  1411 parameters.
  1412 
  1413 * Context expressions: renaming of parameters with syntax
  1414 redeclaration.
  1415 
  1416 * Locale declaration: 'includes' disallowed.
  1417 
  1418 * Proper static binding of attribute syntax -- i.e. types / terms /
  1419 facts mentioned as arguments are always those of the locale definition
  1420 context, independently of the context of later invocations.  Moreover,
  1421 locale operations (renaming and type / term instantiation) are applied
  1422 to attribute arguments as expected.
  1423 
  1424 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1425 actual attributes; rare situations may require Attrib.attribute to
  1426 embed those attributes into Attrib.src that lack concrete syntax.
  1427 Attribute implementations need to cooperate properly with the static
  1428 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1429 Attrib.XXX_thm etc. already do the right thing without further
  1430 intervention.  Only unusual applications -- such as "where" or "of"
  1431 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1432 on the context and the facts involved -- may have to assign parsed
  1433 values to argument tokens explicitly.
  1434 
  1435 * Changed parameter management in theorem generation for long goal
  1436 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1437 theorem statement in rare situations.
  1438 
  1439 * Locale inspection command 'print_locale' omits notes elements.  Use
  1440 'print_locale!' to have them included in the output.
  1441 
  1442 
  1443 *** Provers ***
  1444 
  1445 * Provers/hypsubst.ML: improved version of the subst method, for
  1446 single-step rewriting: it now works in bound variable contexts. New is
  1447 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1448 rewrite a different subterm than the original subst method, which is
  1449 still available as 'simplesubst'.
  1450 
  1451 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1452 and quasi orders.
  1453 
  1454 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1455 reflexive-transitive closure of relations.
  1456 
  1457 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1458 limit (previously hard-coded with a value of 20) user-definable.
  1459 
  1460 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1461 is peformed already.  Object-logics merely need to finish their
  1462 initial simpset configuration as before.  INCOMPATIBILITY.
  1463 
  1464 
  1465 *** HOL ***
  1466 
  1467 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1468 
  1469   syntax (epsilon)
  1470     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1471 
  1472 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1473 and x-symbol; use option '-m epsilon' to get it actually printed.
  1474 Moreover, the mathematically important symbolic identifier \<epsilon>
  1475 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1476 
  1477 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1478 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1479 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1480 support corresponding Isar calculations.
  1481 
  1482 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1483 instead of ":".
  1484 
  1485 * theory SetInterval: changed the syntax for open intervals:
  1486 
  1487   Old       New
  1488   {..n(}    {..<n}
  1489   {)n..}    {n<..}
  1490   {m..n(}   {m..<n}
  1491   {)m..n}   {m<..n}
  1492   {)m..n(}  {m<..<n}
  1493 
  1494 The old syntax is still supported but will disappear in the next
  1495 release.  For conversion use the following Emacs search and replace
  1496 patterns (these are not perfect but work quite well):
  1497 
  1498   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1499   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1500 
  1501 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1502 equalities in commutative rings; method 'algebra' provides a generic
  1503 interface.
  1504 
  1505 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1506 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1507 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1508 be a tuple pattern.
  1509 
  1510 Some new syntax forms are available:
  1511 
  1512   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1513   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1514   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1515   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1516 
  1517 The latter form "\<Sum>x < k. e" used to be based on a separate
  1518 function "Summation", which has been discontinued.
  1519 
  1520 * theory Finite_Set: in structured induction proofs, the insert case
  1521 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1522 (insert F x)'.
  1523 
  1524 * The 'refute' command has been extended to support a much larger
  1525 fragment of HOL, including axiomatic type classes, constdefs and
  1526 typedefs, inductive datatypes and recursion.
  1527 
  1528 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1529 Requires zChaff with proof generation to be installed.  See
  1530 HOL/ex/SAT_Examples.thy for examples.
  1531 
  1532 * Datatype induction via method 'induct' now preserves the name of the
  1533 induction variable. For example, when proving P(xs::'a list) by
  1534 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1535 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1536 in unstructured proof scripts.
  1537 
  1538 * Reworked implementation of records.  Improved scalability for
  1539 records with many fields, avoiding performance problems for type
  1540 inference. Records are no longer composed of nested field types, but
  1541 of nested extension types. Therefore the record type only grows linear
  1542 in the number of extensions and not in the number of fields.  The
  1543 top-level (users) view on records is preserved.  Potential
  1544 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1545 old record representation. The type generated for a record is called
  1546 <record_name>_ext_type.
  1547 
  1548 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1549 proofs triggered by a record definition or a simproc (if
  1550 quick_and_dirty is enabled).  Definitions of large records can take
  1551 quite long.
  1552 
  1553 New simproc record_upd_simproc for simplification of multiple record
  1554 updates enabled by default.  Moreover, trivial updates are also
  1555 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1556 occasionally, since simplification is more powerful by default.
  1557 
  1558 * typedef: proper support for polymorphic sets, which contain extra
  1559 type-variables in the term.
  1560 
  1561 * Simplifier: automatically reasons about transitivity chains
  1562 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1563 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1564 old proofs break occasionally as simplification may now solve more
  1565 goals than previously.
  1566 
  1567 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1568 present.  Works for all partial orders (class "order"), in particular
  1569 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1570 just like y <= x.
  1571 
  1572 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1573 bound variable or a constant then the let is unfolded.  Otherwise
  1574 first a is simplified to b, and then f b is simplified to g. If
  1575 possible we abstract b from g arriving at "let x = b in h x",
  1576 otherwise we unfold the let and arrive at g.  The simproc can be
  1577 enabled/disabled by the reference use_let_simproc.  Potential
  1578 INCOMPATIBILITY since simplification is more powerful by default.
  1579 
  1580 * Classical reasoning: the meson method now accepts theorems as arguments.
  1581 
  1582 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1583 jobs to provide advice on the provability of subgoals.
  1584 
  1585 * Theory OrderedGroup and Ring_and_Field: various additions and
  1586 improvements to faciliate calculations involving equalities and
  1587 inequalities.
  1588 
  1589 The following theorems have been eliminated or modified
  1590 (INCOMPATIBILITY):
  1591 
  1592   abs_eq             now named abs_of_nonneg
  1593   abs_of_ge_0        now named abs_of_nonneg
  1594   abs_minus_eq       now named abs_of_nonpos
  1595   imp_abs_id         now named abs_of_nonneg
  1596   imp_abs_neg_id     now named abs_of_nonpos
  1597   mult_pos           now named mult_pos_pos
  1598   mult_pos_le        now named mult_nonneg_nonneg
  1599   mult_pos_neg_le    now named mult_nonneg_nonpos
  1600   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1601   mult_neg           now named mult_neg_neg
  1602   mult_neg_le        now named mult_nonpos_nonpos
  1603 
  1604 * Theory Parity: added rules for simplifying exponents.
  1605 
  1606 * Theory List:
  1607 
  1608 The following theorems have been eliminated or modified
  1609 (INCOMPATIBILITY):
  1610 
  1611   list_all_Nil       now named list_all.simps(1)
  1612   list_all_Cons      now named list_all.simps(2)
  1613   list_all_conv      now named list_all_iff
  1614   set_mem_eq         now named mem_iff
  1615 
  1616 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1617 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1618 
  1619 
  1620 *** HOL-Complex ***
  1621 
  1622 * Theory RealDef: better support for embedding natural numbers and
  1623 integers in the reals.
  1624 
  1625 The following theorems have been eliminated or modified
  1626 (INCOMPATIBILITY):
  1627 
  1628   exp_ge_add_one_self  now requires no hypotheses
  1629   real_of_int_add      reversed direction of equality (use [symmetric])
  1630   real_of_int_minus    reversed direction of equality (use [symmetric])
  1631   real_of_int_diff     reversed direction of equality (use [symmetric])
  1632   real_of_int_mult     reversed direction of equality (use [symmetric])
  1633 
  1634 * Theory RComplete: expanded support for floor and ceiling functions.
  1635 
  1636 * Theory Ln is new, with properties of the natural logarithm
  1637 
  1638 * Hyperreal: There is a new type constructor "star" for making
  1639 nonstandard types.  The old type names are now type synonyms:
  1640 
  1641   hypreal = real star
  1642   hypnat = nat star
  1643   hcomplex = complex star
  1644 
  1645 * Hyperreal: Many groups of similarly-defined constants have been
  1646 replaced by polymorphic versions (INCOMPATIBILITY):
  1647 
  1648   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1649 
  1650   starset      <-- starsetNat, starsetC
  1651   *s*          <-- *sNat*, *sc*
  1652   starset_n    <-- starsetNat_n, starsetC_n
  1653   *sn*         <-- *sNatn*, *scn*
  1654   InternalSets <-- InternalNatSets, InternalCSets
  1655 
  1656   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1657   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1658   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1659   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1660   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1661 
  1662 * Hyperreal: Many type-specific theorems have been removed in favor of
  1663 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1664 
  1665   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1666   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1667   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1668   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1669   right_minus <-- hypreal_add_minus
  1670   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1671   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1672   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1673   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1674   mult_1_right <-- hcomplex_mult_one_right
  1675   mult_zero_left <-- hcomplex_mult_zero_left
  1676   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1677   right_distrib <-- hypnat_add_mult_distrib2
  1678   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1679   right_inverse <-- hypreal_mult_inverse
  1680   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1681   order_refl <-- {hypreal,hypnat}_le_refl
  1682   order_trans <-- {hypreal,hypnat}_le_trans
  1683   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1684   order_less_le <-- {hypreal,hypnat}_less_le
  1685   linorder_linear <-- {hypreal,hypnat}_le_linear
  1686   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1687   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1688   add_nonneg_nonneg <-- hypreal_le_add_order
  1689 
  1690 * Hyperreal: Separate theorems having to do with type-specific
  1691 versions of constants have been merged into theorems that apply to the
  1692 new polymorphic constants (INCOMPATIBILITY):
  1693 
  1694   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1695   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1696   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1697   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1698   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1699   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1700   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1701   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1702   STAR_diff <-- {STAR,STARC}_diff
  1703   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1704     STARC_hcomplex_of_complex}_image_subset
  1705   starset_n_Un <-- starset{Nat,C}_n_Un
  1706   starset_n_Int <-- starset{Nat,C}_n_Int
  1707   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1708   starset_n_diff <-- starset{Nat,C}_n_diff
  1709   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1710   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1711   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1712   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1713   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1714   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1715   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1716   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1717   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1718   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1719   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1720   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1721   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1722   starfun_diff <-- starfun{C,RC,CR}_diff
  1723   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1724   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1725   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1726   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1727   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1728   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1729   starfun_Id <-- starfunC_Id
  1730   starfun_approx <-- starfun{Nat,CR}_approx
  1731   starfun_capprox <-- starfun{C,RC}_capprox
  1732   starfun_abs <-- starfunNat_rabs
  1733   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1734   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1735   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1736   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1737   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1738   starfun_add_approx <-- starfunCR_add_approx
  1739   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1740   starfun_divide <-- starfun{C,CR,RC}_divide
  1741   starfun_n <-- starfun{Nat,C}_n
  1742   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1743   starfun_n_add <-- starfun{Nat,C}_n_add
  1744   starfun_n_add_minus <-- starfunNat_n_add_minus
  1745   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1746   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1747   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1748 
  1749   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1750   star_n_minus <-- {hypreal,hcomplex}_minus
  1751   star_n_diff <-- {hypreal,hcomplex}_diff
  1752   star_n_mult <-- {hypreal,hcomplex}_mult
  1753   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1754   star_n_le <-- {hypreal,hypnat}_le
  1755   star_n_less <-- {hypreal,hypnat}_less
  1756   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1757   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1758   star_n_abs <-- hypreal_hrabs
  1759   star_n_divide <-- hcomplex_divide
  1760 
  1761   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1762   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1763   star_of_diff <-- hypreal_of_real_diff
  1764   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1765   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1766   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1767   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1768   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1769   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1770   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1771   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1772   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1773   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1774   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1775   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1776   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1777   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1778   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1779   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1780   star_of_power <-- hypreal_of_real_power
  1781   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1782 
  1783 * Hyperreal: new method "transfer" that implements the transfer
  1784 principle of nonstandard analysis. With a subgoal that mentions
  1785 nonstandard types like "'a star", the command "apply transfer"
  1786 replaces it with an equivalent one that mentions only standard types.
  1787 To be successful, all free variables must have standard types; non-
  1788 standard variables must have explicit universal quantifiers.
  1789 
  1790 * Hyperreal: A theory of Taylor series.
  1791 
  1792 
  1793 *** HOLCF ***
  1794 
  1795 * Discontinued special version of 'constdefs' (which used to support
  1796 continuous functions) in favor of the general Pure one with full
  1797 type-inference.
  1798 
  1799 * New simplification procedure for solving continuity conditions; it
  1800 is much faster on terms with many nested lambda abstractions (cubic
  1801 instead of exponential time).
  1802 
  1803 * New syntax for domain package: selector names are now optional.
  1804 Parentheses should be omitted unless argument is lazy, for example:
  1805 
  1806   domain 'a stream = cons "'a" (lazy "'a stream")
  1807 
  1808 * New command 'fixrec' for defining recursive functions with pattern
  1809 matching; defining multiple functions with mutual recursion is also
  1810 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1811 sinr, or any data constructor defined by the domain package. The given
  1812 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1813 syntax and examples.
  1814 
  1815 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1816 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1817 but the proof obligation additionally includes an admissibility
  1818 requirement. The packages generate instances of class cpo or pcpo,
  1819 with continuity and strictness theorems for Rep and Abs.
  1820 
  1821 * HOLCF: Many theorems have been renamed according to a more standard naming
  1822 scheme (INCOMPATIBILITY):
  1823 
  1824   foo_inject:  "foo$x = foo$y ==> x = y"
  1825   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1826   foo_less:    "(foo$x << foo$y) = (x << y)"
  1827   foo_strict:  "foo$UU = UU"
  1828   foo_defined: "... ==> foo$x ~= UU"
  1829   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1830 
  1831 
  1832 *** ZF ***
  1833 
  1834 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1835 including the First Isomorphism Theorem (on quotienting by the kernel
  1836 of a homomorphism).
  1837 
  1838 * ZF/Simplifier: install second copy of type solver that actually
  1839 makes use of TC rules declared to Isar proof contexts (or locales);
  1840 the old version is still required for ML proof scripts.
  1841 
  1842 
  1843 *** Cube ***
  1844 
  1845 * Converted to Isar theory format; use locales instead of axiomatic
  1846 theories.
  1847 
  1848 
  1849 *** ML ***
  1850 
  1851 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1852 for ||>, ||>>, |>>,
  1853 
  1854 * Pure/library.ML no longer defines its own option datatype, but uses
  1855 that of the SML basis, which has constructors NONE and SOME instead of
  1856 None and Some, as well as exception Option.Option instead of OPTION.
  1857 The functions the, if_none, is_some, is_none have been adapted
  1858 accordingly, while Option.map replaces apsome.
  1859 
  1860 * Pure/library.ML: the exception LIST has been given up in favour of
  1861 the standard exceptions Empty and Subscript, as well as
  1862 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1863 superceded by the standard hd and tl functions etc.
  1864 
  1865 A number of basic list functions are no longer exported to the ML
  1866 toplevel, as they are variants of predefined functions.  The following
  1867 suggests how one can translate existing code:
  1868 
  1869     rev_append xs ys = List.revAppend (xs, ys)
  1870     nth_elem (i, xs) = List.nth (xs, i)
  1871     last_elem xs = List.last xs
  1872     flat xss = List.concat xss
  1873     seq fs = List.app fs
  1874     partition P xs = List.partition P xs
  1875     mapfilter f xs = List.mapPartial f xs
  1876 
  1877 * Pure/library.ML: several combinators for linear functional
  1878 transformations, notably reverse application and composition:
  1879 
  1880   x |> f                f #> g
  1881   (x, y) |-> f          f #-> g
  1882 
  1883 * Pure/library.ML: introduced/changed precedence of infix operators:
  1884 
  1885   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1886   infix 2 ?;
  1887   infix 3 o oo ooo oooo;
  1888   infix 4 ~~ upto downto;
  1889 
  1890 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1891 infix operators.
  1892 
  1893 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1894 fold_map support linear functional transformations and nesting.  For
  1895 example:
  1896 
  1897   fold f [x1, ..., xN] y =
  1898     y |> f x1 |> ... |> f xN
  1899 
  1900   (fold o fold) f [xs1, ..., xsN] y =
  1901     y |> fold f xs1 |> ... |> fold f xsN
  1902 
  1903   fold f [x1, ..., xN] =
  1904     f x1 #> ... #> f xN
  1905 
  1906   (fold o fold) f [xs1, ..., xsN] =
  1907     fold f xs1 #> ... #> fold f xsN
  1908 
  1909 * Pure/library.ML: the following selectors on type 'a option are
  1910 available:
  1911 
  1912   the:               'a option -> 'a  (*partial*)
  1913   these:             'a option -> 'a  where 'a = 'b list
  1914   the_default: 'a -> 'a option -> 'a
  1915   the_list:          'a option -> 'a list
  1916 
  1917 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1918 basic operations for association lists, following natural argument
  1919 order; moreover the explicit equality predicate passed here avoids
  1920 potentially expensive polymorphic runtime equality checks.
  1921 The old functions may be expressed as follows:
  1922 
  1923   assoc = uncurry (AList.lookup (op =))
  1924   assocs = these oo AList.lookup (op =)
  1925   overwrite = uncurry (AList.update (op =)) o swap
  1926 
  1927 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1928 
  1929   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1930   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1931 
  1932 replacing make_keylist and keyfilter (occassionally used)
  1933 Naive rewrites:
  1934 
  1935   make_keylist = AList.make
  1936   keyfilter = AList.find (op =)
  1937 
  1938 * eq_fst and eq_snd now take explicit equality parameter, thus
  1939   avoiding eqtypes. Naive rewrites:
  1940 
  1941     eq_fst = eq_fst (op =)
  1942     eq_snd = eq_snd (op =)
  1943 
  1944 * Removed deprecated apl and apr (rarely used).
  1945   Naive rewrites:
  1946 
  1947     apl (n, op) =>>= curry op n
  1948     apr (op, m) =>>= fn n => op (n, m)
  1949 
  1950 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1951 provides a reasonably efficient light-weight implementation of sets as
  1952 lists.
  1953 
  1954 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1955 few new operations; existing lookup and update are now curried to
  1956 follow natural argument order (for use with fold etc.);
  1957 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1958 
  1959 * Pure/General: output via the Isabelle channels of
  1960 writeln/warning/error etc. is now passed through Output.output, with a
  1961 hook for arbitrary transformations depending on the print_mode
  1962 (cf. Output.add_mode -- the first active mode that provides a output
  1963 function wins).  Already formatted output may be embedded into further
  1964 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1965 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1966 accommodate easy composition of diagnostic messages etc.  Programmers
  1967 rarely need to care about Output.output or Output.raw at all, with
  1968 some notable exceptions: Output.output is required when bypassing the
  1969 standard channels (writeln etc.), or in token translations to produce
  1970 properly formatted results; Output.raw is required when capturing
  1971 already output material that will eventually be presented to the user
  1972 a second time.  For the default print mode, both Output.output and
  1973 Output.raw have no effect.
  1974 
  1975 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1976 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1977 cumulative results are displayed at the end of a batch session.
  1978 
  1979 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1980 replaced by File.platform_path and File.shell_path (with appropriate
  1981 hooks).  This provides a clean interface for unusual systems where the
  1982 internal and external process view of file names are different.
  1983 
  1984 * Pure: more efficient orders for basic syntactic entities: added
  1985 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1986 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1987 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1988 orders now -- potential INCOMPATIBILITY for code that depends on a
  1989 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1990 Library.sort_strings on result).
  1991 
  1992 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1993 fold_types traverse types/terms from left to right, observing natural
  1994 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1995 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1996 
  1997 * Pure: name spaces have been refined, with significant changes of the
  1998 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1999 to extern(_table).  The plain name entry path is superceded by a
  2000 general 'naming' context, which also includes the 'policy' to produce
  2001 a fully qualified name and external accesses of a fully qualified
  2002 name; NameSpace.extend is superceded by context dependent
  2003 Sign.declare_name.  Several theory and proof context operations modify
  2004 the naming context.  Especially note Theory.restore_naming and
  2005 ProofContext.restore_naming to get back to a sane state; note that
  2006 Theory.add_path is no longer sufficient to recover from
  2007 Theory.absolute_path in particular.
  2008 
  2009 * Pure: new flags short_names (default false) and unique_names
  2010 (default true) for controlling output of qualified names.  If
  2011 short_names is set, names are printed unqualified.  If unique_names is
  2012 reset, the name prefix is reduced to the minimum required to achieve
  2013 the original result when interning again, even if there is an overlap
  2014 with earlier declarations.
  2015 
  2016 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2017 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2018 (useful for printing error messages).  INCOMPATIBILITY.
  2019 
  2020 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2021 Theory.theory are now identified, referring to the universal
  2022 Context.theory (see Pure/context.ML).  Actual signature and theory
  2023 content is managed as theory data.  The old code and interfaces were
  2024 spread over many files and structures; the new arrangement introduces
  2025 considerable INCOMPATIBILITY to gain more clarity:
  2026 
  2027   Context -- theory management operations (name, identity, inclusion,
  2028     parents, ancestors, merge, etc.), plus generic theory data;
  2029 
  2030   Sign -- logical signature and syntax operations (declaring consts,
  2031     types, etc.), plus certify/read for common entities;
  2032 
  2033   Theory -- logical theory operations (stating axioms, definitions,
  2034     oracles), plus a copy of logical signature operations (consts,
  2035     types, etc.); also a few basic management operations (Theory.copy,
  2036     Theory.merge, etc.)
  2037 
  2038 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2039 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2040 for convenience -- they merely return the theory.
  2041 
  2042 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2043 
  2044 * Pure: the Isar proof context type is already defined early in Pure
  2045 as Context.proof (note that ProofContext.context and Proof.context are
  2046 aliases, where the latter is the preferred name).  This enables other
  2047 Isabelle components to refer to that type even before Isar is present.
  2048 
  2049 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2050 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2051 any of these kinds.  For example, Sign.intern typeK is now
  2052 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2053 Theory.hide_types.  Also note that former
  2054 Theory.hide_classes/types/consts are now
  2055 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2056 internalize their arguments!  INCOMPATIBILITY.
  2057 
  2058 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2059 datatype thmref (with constructors Name and NameSelection) instead of
  2060 plain string -- INCOMPATIBILITY;
  2061 
  2062 * Pure: cases produced by proof methods specify options, where NONE
  2063 means to remove case bindings -- INCOMPATIBILITY in
  2064 (RAW_)METHOD_CASES.
  2065 
  2066 * Pure: the following operations retrieve axioms or theorems from a
  2067 theory node or theory hierarchy, respectively:
  2068 
  2069   Theory.axioms_of: theory -> (string * term) list
  2070   Theory.all_axioms_of: theory -> (string * term) list
  2071   PureThy.thms_of: theory -> (string * thm) list
  2072   PureThy.all_thms_of: theory -> (string * thm) list
  2073 
  2074 * Pure: print_tac now outputs the goal through the trace channel.
  2075 
  2076 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2077 Reference Toplevel.debug (default false) controls detailed printing
  2078 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2079 controls execution profiling -- set to 1 for time and 2 for space
  2080 (both increase the runtime).
  2081 
  2082 * Isar session: The initial use of ROOT.ML is now always timed,
  2083 i.e. the log will show the actual process times, in contrast to the
  2084 elapsed wall-clock time that the outer shell wrapper produces.
  2085 
  2086 * Simplifier: improved handling of bound variables (nameless
  2087 representation, avoid allocating new strings).  Simprocs that invoke
  2088 the Simplifier recursively should use Simplifier.inherit_bounds to
  2089 avoid local name clashes.  Failure to do so produces warnings
  2090 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2091 for further details.
  2092 
  2093 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2094 bindings for all theorems stored within a given theory; this may help
  2095 in porting non-Isar theories to Isar ones, while keeping ML proof
  2096 scripts for the time being.
  2097 
  2098 * ML operator HTML.with_charset specifies the charset begin used for
  2099 generated HTML files.  For example:
  2100 
  2101   HTML.with_charset "utf-8" use_thy "Hebrew";
  2102   HTML.with_charset "utf-8" use_thy "Chinese";
  2103 
  2104 
  2105 *** System ***
  2106 
  2107 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2108 isabelle, isatool etc.).
  2109 
  2110 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2111 isatool doc, isatool mkdir, display_drafts etc.).
  2112 
  2113 * isatool usedir: option -f allows specification of the ML file to be
  2114 used by Isabelle; default is ROOT.ML.
  2115 
  2116 * New isatool version outputs the version identifier of the Isabelle
  2117 distribution being used.
  2118 
  2119 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2120 (containing Boolean satisfiability problems) into Isabelle/HOL
  2121 theories.
  2122 
  2123 
  2124 
  2125 New in Isabelle2004 (April 2004)
  2126 --------------------------------
  2127 
  2128 *** General ***
  2129 
  2130 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2131   Replaces linorder.ML.
  2132 
  2133 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2134   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2135   (\<a>...\<z>), are now considered normal letters, and can therefore
  2136   be used anywhere where an ASCII letter (a...zA...Z) has until
  2137   now. COMPATIBILITY: This obviously changes the parsing of some
  2138   terms, especially where a symbol has been used as a binder, say
  2139   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2140   as an identifier.  Fix it by inserting a space around former
  2141   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2142   existing theory and ML files.
  2143 
  2144 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2145 
  2146 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2147   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2148   a normal (but invisible) letter. For multiple letter subscripts repeat
  2149   \<^isub> like this: x\<^isub>1\<^isub>2.
  2150 
  2151 * Pure: There are now sub-/superscripts that can span more than one
  2152   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2153   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2154   superscript. The new control characters are not identifier parts.
  2155 
  2156 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2157   content of "..." to the latex file instead of \isacntrl... . The "..."
  2158   may consist of any printable characters excluding the end bracket >.
  2159 
  2160 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2161   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2162   declare constants "final", which prevents their being given a definition
  2163   later.  It is useful for constants whose behaviour is fixed axiomatically
  2164   rather than definitionally, such as the meta-logic connectives.
  2165 
  2166 * Pure: 'instance' now handles general arities with general sorts
  2167   (i.e. intersections of classes),
  2168 
  2169 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2170   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2171   It can be changed to alter the colors/layout of generated pages.
  2172 
  2173 
  2174 *** Isar ***
  2175 
  2176 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2177   cut_tac, subgoal_tac and thin_tac:
  2178   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2179     locales are no longer forced to write Isar proof scripts.
  2180     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2181     emulations.
  2182   - INCOMPATIBILITY: names of variables to be instantiated may no
  2183     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2184     This is consistent with the instantiation attribute "where".
  2185 
  2186 * Attributes "where" and "of":
  2187   - Now take type variables of instantiated theorem into account when reading
  2188     the instantiation string.  This fixes a bug that caused instantiated
  2189     theorems to have too special types in some circumstances.
  2190   - "where" permits explicit instantiations of type variables.
  2191 
  2192 * Calculation commands "moreover" and "also" no longer interfere with
  2193   current facts ("this"), admitting arbitrary combinations with "then"
  2194   and derived forms.
  2195 
  2196 * Locales:
  2197   - Goal statements involving the context element "includes" no longer
  2198     generate theorems with internal delta predicates (those ending on
  2199     "_axioms") in the premise.
  2200     Resolve particular premise with <locale>.intro to obtain old form.
  2201   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2202     specification and "includes" elements in goal statement.
  2203   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2204     [intro?] and [elim?] (respectively) by default.
  2205   - Experimental command for instantiation of locales in proof contexts:
  2206         instantiate <label>[<attrs>]: <loc>
  2207     Instantiates locale <loc> and adds all its theorems to the current context
  2208     taking into account their attributes.  Label and attrs are optional
  2209     modifiers, like in theorem declarations.  If present, names of
  2210     instantiated theorems are qualified with <label>, and the attributes
  2211     <attrs> are applied after any attributes these theorems might have already.
  2212       If the locale has assumptions, a chained fact of the form
  2213     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2214     are derived.  The command does not support old-style locales declared
  2215     with "locale (open)".
  2216       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2217 
  2218 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2219   (Isar) contexts.
  2220 
  2221 
  2222 *** HOL ***
  2223 
  2224 * Proof import: new image HOL4 contains the imported library from
  2225   the HOL4 system with about 2500 theorems. It is imported by
  2226   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2227   can be used like any other Isabelle image.  See
  2228   HOL/Import/HOL/README for more information.
  2229 
  2230 * Simplifier:
  2231   - Much improved handling of linear and partial orders.
  2232     Reasoners for linear and partial orders are set up for type classes
  2233     "linorder" and "order" respectively, and are added to the default simpset
  2234     as solvers.  This means that the simplifier can build transitivity chains
  2235     to solve goals from the assumptions.
  2236   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2237     of blast or auto after simplification become unnecessary because the goal
  2238     is solved by simplification already.
  2239 
  2240 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2241     all proved in axiomatic type classes for semirings, rings and fields.
  2242 
  2243 * Numerics:
  2244   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2245     now formalized using the Ring_and_Field theory mentioned above.
  2246   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2247     than before, because now they are set up once in a generic manner.
  2248   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2249     Look for the general versions in Ring_and_Field (and Power if they concern
  2250     exponentiation).
  2251 
  2252 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2253 
  2254 * Records:
  2255   - Record types are now by default printed with their type abbreviation
  2256     instead of the list of all field types. This can be configured via
  2257     the reference "print_record_type_abbr".
  2258   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2259     (not enabled by default).
  2260   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2261     EX x. x = sel r to True (not enabled by default).
  2262   - Tactic "record_split_simp_tac" to split and simplify records added.
  2263 
  2264 * 'specification' command added, allowing for definition by
  2265   specification.  There is also an 'ax_specification' command that
  2266   introduces the new constants axiomatically.
  2267 
  2268 * arith(_tac) is now able to generate counterexamples for reals as well.
  2269 
  2270 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2271 
  2272 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2273   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2274 
  2275 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2276   matrix theory to linear programming.
  2277 
  2278 * Unions and Intersections:
  2279   The latex output syntax of UN and INT has been changed
  2280   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2281   i.e. the index formulae has become a subscript.
  2282   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2283 
  2284 * Unions and Intersections over Intervals:
  2285   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2286   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2287   like in normal math, and corresponding versions for < and for intersection.
  2288 
  2289 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2290   lexicographic dictonary ordering has been added as "lexord".
  2291 
  2292 * ML: the legacy theory structures Int and List have been removed. They had
  2293   conflicted with ML Basis Library structures having the same names.
  2294 
  2295 * 'refute' command added to search for (finite) countermodels.  Only works
  2296   for a fragment of HOL.  The installation of an external SAT solver is
  2297   highly recommended.  See "HOL/Refute.thy" for details.
  2298 
  2299 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2300   formulae under an assignment of free variables to random values.
  2301   In contrast to 'refute', it can deal with inductive datatypes,
  2302   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2303   for examples.
  2304 
  2305 
  2306 *** HOLCF ***
  2307 
  2308 * Streams now come with concatenation and are part of the HOLCF image
  2309 
  2310 
  2311 
  2312 New in Isabelle2003 (May 2003)
  2313 ------------------------------
  2314 
  2315 *** General ***
  2316 
  2317 * Provers/simplifier:
  2318 
  2319   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2320     Assumptions are now subject to complete mutual simplification,
  2321     not just from left to right. The simplifier now preserves
  2322     the order of assumptions.
  2323 
  2324     Potential INCOMPATIBILITY:
  2325 
  2326     -- simp sometimes diverges where the old version did
  2327        not, e.g. invoking simp on the goal
  2328 
  2329         [| P (f x); y = x; f x = f y |] ==> Q
  2330 
  2331        now gives rise to the infinite reduction sequence
  2332 
  2333         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2334 
  2335        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2336        kind of problem.
  2337 
  2338     -- Tactics combining classical reasoner and simplification (such as auto)
  2339        are also affected by this change, because many of them rely on
  2340        simp. They may sometimes diverge as well or yield a different numbers
  2341        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2342        in case of problems. Sometimes subsequent calls to the classical
  2343        reasoner will fail because a preceeding call to the simplifier too
  2344        eagerly simplified the goal, e.g. deleted redundant premises.
  2345 
  2346   - The simplifier trace now shows the names of the applied rewrite rules
  2347 
  2348   - You can limit the number of recursive invocations of the simplifier
  2349     during conditional rewriting (where the simplifie tries to solve the
  2350     conditions before applying the rewrite rule):
  2351     ML "simp_depth_limit := n"
  2352     where n is an integer. Thus you can force termination where previously
  2353     the simplifier would diverge.
  2354 
  2355   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2356 
  2357   - No longer aborts on failed congruence proof.  Instead, the
  2358     congruence is ignored.
  2359 
  2360 * Pure: New generic framework for extracting programs from constructive
  2361   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2362   as HOL/Extraction for some case studies.
  2363 
  2364 * Pure: The main goal of the proof state is no longer shown by default, only
  2365 the subgoals. This behaviour is controlled by a new flag.
  2366    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2367 (ML: Proof.show_main_goal).
  2368 
  2369 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2370 rules whose conclusion matches subgoal 1:
  2371       PG menu: Isabelle/Isar -> Show me -> matching rules
  2372 The rules are ordered by how closely they match the subgoal.
  2373 In particular, rules that solve a subgoal outright are displayed first
  2374 (or rather last, the way they are printed).
  2375 (ML: ProofGeneral.print_intros())
  2376 
  2377 * Pure: New flag trace_unify_fail causes unification to print
  2378 diagnostic information (PG: in trace buffer) when it fails. This is
  2379 useful for figuring out why single step proofs like rule, erule or
  2380 assumption failed.
  2381 
  2382 * Pure: Locale specifications now produce predicate definitions
  2383 according to the body of text (covering assumptions modulo local
  2384 definitions); predicate "loc_axioms" covers newly introduced text,
  2385 while "loc" is cumulative wrt. all included locale expressions; the
  2386 latter view is presented only on export into the global theory
  2387 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2388 on the old view without predicates;
  2389 
  2390 * Pure: predefined locales "var" and "struct" are useful for sharing
  2391 parameters (as in CASL, for example); just specify something like
  2392 ``var x + var y + struct M'' as import;
  2393 
  2394 * Pure: improved thms_containing: proper indexing of facts instead of
  2395 raw theorems; check validity of results wrt. current name space;
  2396 include local facts of proof configuration (also covers active
  2397 locales), cover fixed variables in index; may use "_" in term
  2398 specification; an optional limit for the number of printed facts may
  2399 be given (the default is 40);
  2400 
  2401 * Pure: disallow duplicate fact bindings within new-style theory files
  2402 (batch-mode only);
  2403 
  2404 * Provers: improved induct method: assumptions introduced by case
  2405 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2406 the goal statement); "foo" still refers to all facts collectively;
  2407 
  2408 * Provers: the function blast.overloaded has been removed: all constants
  2409 are regarded as potentially overloaded, which improves robustness in exchange
  2410 for slight decrease in efficiency;
  2411 
  2412 * Provers/linorder: New generic prover for transitivity reasoning over
  2413 linear orders.  Note: this prover is not efficient!
  2414 
  2415 * Isar: preview of problems to finish 'show' now produce an error
  2416 rather than just a warning (in interactive mode);
  2417 
  2418 
  2419 *** HOL ***
  2420 
  2421 * arith(_tac)
  2422 
  2423  - Produces a counter example if it cannot prove a goal.
  2424    Note that the counter example may be spurious if the goal is not a formula
  2425    of quantifier-free linear arithmetic.
  2426    In ProofGeneral the counter example appears in the trace buffer.
  2427 
  2428  - Knows about div k and mod k where k is a numeral of type nat or int.
  2429 
  2430  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2431    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2432    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2433 
  2434 * simp's arithmetic capabilities have been enhanced a bit: it now
  2435 takes ~= in premises into account (by performing a case split);
  2436 
  2437 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2438 are distributed over a sum of terms;
  2439 
  2440 * New tactic "trans_tac" and method "trans" instantiate
  2441 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2442 "<=", "<" and "=").
  2443 
  2444 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2445 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2446 
  2447 * 'typedef' command has new option "open" to suppress the set
  2448 definition;
  2449 
  2450 * functions Min and Max on finite sets have been introduced (theory
  2451 Finite_Set);
  2452 
  2453 * attribute [symmetric] now works for relations as well; it turns
  2454 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2455 
  2456 * induct over a !!-quantified statement (say !!x1..xn):
  2457   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2458 
  2459 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2460 %x. None. Warning: empty_def now refers to the previously hidden definition
  2461 of the empty set.
  2462 
  2463 * Algebra: formalization of classical algebra.  Intended as base for
  2464 any algebraic development in Isabelle.  Currently covers group theory
  2465 (up to Sylow's theorem) and ring theory (Universal Property of
  2466 Univariate Polynomials).  Contributions welcome;
  2467 
  2468 * GroupTheory: deleted, since its material has been moved to Algebra;
  2469 
  2470 * Complex: new directory of the complex numbers with numeric constants,
  2471 nonstandard complex numbers, and some complex analysis, standard and
  2472 nonstandard (Jacques Fleuriot);
  2473 
  2474 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2475 
  2476 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2477 Fleuriot);
  2478 
  2479 * Real/HahnBanach: updated and adapted to locales;
  2480 
  2481 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2482 Gray and Kramer);
  2483 
  2484 * UNITY: added the Meier-Sanders theory of progress sets;
  2485 
  2486 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2487 as abstract algorithms, instantiated to the JVM;
  2488 
  2489 * Bali: Java source language formalization. Type system, operational
  2490 semantics, axiomatic semantics. Supported language features:
  2491 classes, interfaces, objects,virtual methods, static methods,
  2492 static/instance fields, arrays, access modifiers, definite
  2493 assignment, exceptions.
  2494 
  2495 
  2496 *** ZF ***
  2497 
  2498 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2499 universe, etc.);
  2500 
  2501 * Main ZF: virtually all theories converted to new-style format;
  2502 
  2503 
  2504 *** ML ***
  2505 
  2506 * Pure: Tactic.prove provides sane interface for internal proofs;
  2507 omits the infamous "standard" operation, so this is more appropriate
  2508 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2509 
  2510 * Pure: improved error reporting of simprocs;
  2511 
  2512 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2513 up simprocs;
  2514 
  2515 
  2516 *** Document preparation ***
  2517 
  2518 * uses \par instead of \\ for line breaks in theory text. This may
  2519 shift some page breaks in large documents. To get the old behaviour
  2520 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2521 
  2522 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2523 other packages
  2524 
  2525 * \<euro> now needs package babel/greek instead of marvosym (which
  2526 broke \Rightarrow)
  2527 
  2528 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2529 textcomp package)
  2530 
  2531 
  2532 
  2533 New in Isabelle2002 (March 2002)
  2534 --------------------------------
  2535 
  2536 *** Document preparation ***
  2537 
  2538 * greatly simplified document preparation setup, including more
  2539 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2540 instructive isatool mkdir; users should basically be able to get
  2541 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2542 users may run a separate document processing stage manually like this:
  2543 "isatool usedir -D output HOL Test && isatool document Test/output";
  2544 
  2545 * theory dependency graph may now be incorporated into documents;
  2546 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2547 with \includegraphics of LaTeX;
  2548 
  2549 * proper spacing of consecutive markup elements, especially text
  2550 blocks after section headings;
  2551 
  2552 * support bold style (for single symbols only), input syntax is like
  2553 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2554 
  2555 * \<bullet> is now output as bold \cdot by default, which looks much
  2556 better in printed text;
  2557 
  2558 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2559 note that these symbols are currently unavailable in Proof General /
  2560 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2561 
  2562 * isatool latex no longer depends on changed TEXINPUTS, instead
  2563 isatool document copies the Isabelle style files to the target
  2564 location;
  2565 
  2566 
  2567 *** Isar ***
  2568 
  2569 * Pure/Provers: improved proof by cases and induction;
  2570   - 'case' command admits impromptu naming of parameters (such as
  2571     "case (Suc n)");
  2572   - 'induct' method divinates rule instantiation from the inductive
  2573     claim; no longer requires excessive ?P bindings for proper
  2574     instantiation of cases;
  2575   - 'induct' method properly enumerates all possibilities of set/type
  2576     rules; as a consequence facts may be also passed through *type*
  2577     rules without further ado;
  2578   - 'induct' method now derives symbolic cases from the *rulified*
  2579     rule (before it used to rulify cases stemming from the internal
  2580     atomized version); this means that the context of a non-atomic
  2581     statement becomes is included in the hypothesis, avoiding the
  2582     slightly cumbersome show "PROP ?case" form;
  2583   - 'induct' may now use elim-style induction rules without chaining
  2584     facts, using ``missing'' premises from the goal state; this allows
  2585     rules stemming from inductive sets to be applied in unstructured
  2586     scripts, while still benefitting from proper handling of non-atomic
  2587     statements; NB: major inductive premises need to be put first, all
  2588     the rest of the goal is passed through the induction;
  2589   - 'induct' proper support for mutual induction involving non-atomic
  2590     rule statements (uses the new concept of simultaneous goals, see
  2591     below);
  2592   - append all possible rule selections, but only use the first
  2593     success (no backtracking);
  2594   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2595   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2596   - added 'print_induct_rules' (covered by help item in recent Proof
  2597     General versions);
  2598   - moved induct/cases attributes to Pure, methods to Provers;
  2599   - generic method setup instantiated for FOL and HOL;
  2600 
  2601 * Pure: support multiple simultaneous goal statements, for example
  2602 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2603 meta-level mechanism, this acts as if several individual goals had
  2604 been stated separately; in particular common proof methods need to be
  2605 repeated in order to cover all claims; note that a single elimination
  2606 step is *not* sufficient to establish the two conjunctions, so this
  2607 fails:
  2608 
  2609   assume "A & B" then have A and B ..   (*".." fails*)
  2610 
  2611 better use "obtain" in situations as above; alternative refer to
  2612 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2613 
  2614 * Pure: proper integration with ``locales''; unlike the original
  2615 version by Florian Kammller, Isar locales package high-level proof
  2616 contexts rather than raw logical ones (e.g. we admit to include
  2617 attributes everywhere); operations on locales include merge and
  2618 rename; support for implicit arguments (``structures''); simultaneous
  2619 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2620 some examples;
  2621 
  2622 * Pure: the following commands have been ``localized'', supporting a
  2623 target locale specification "(in name)": 'lemma', 'theorem',
  2624 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2625 stored both within the locale and at the theory level (exported and
  2626 qualified by the locale name);
  2627 
  2628 * Pure: theory goals may now be specified in ``long'' form, with
  2629 ad-hoc contexts consisting of arbitrary locale elements. for example
  2630 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2631 definitions may be given, too); the result is a meta-level rule with
  2632 the context elements being discharged in the obvious way;
  2633 
  2634 * Pure: new proof command 'using' allows to augment currently used
  2635 facts after a goal statement ('using' is syntactically analogous to
  2636 'apply', but acts on the goal's facts only); this allows chained facts
  2637 to be separated into parts given before and after a claim, as in
  2638 ``from a and b have C using d and e <proof>'';
  2639 
  2640 * Pure: renamed "antecedent" case to "rule_context";
  2641 
  2642 * Pure: new 'judgment' command records explicit information about the
  2643 object-logic embedding (used by several tools internally); no longer
  2644 use hard-wired "Trueprop";
  2645 
  2646 * Pure: added 'corollary' command;
  2647 
  2648 * Pure: fixed 'token_translation' command;
  2649 
  2650 * Pure: removed obsolete 'exported' attribute;
  2651 
  2652 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2653 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2654 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2655 
  2656 * Pure: method 'atomize' presents local goal premises as object-level
  2657 statements (atomic meta-level propositions); setup controlled via
  2658 rewrite rules declarations of 'atomize' attribute; example
  2659 application: 'induct' method with proper rule statements in improper
  2660 proof *scripts*;
  2661 
  2662 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2663 now consider the syntactic context of assumptions, giving a better
  2664 chance to get type-inference of the arguments right (this is
  2665 especially important for locales);
  2666 
  2667 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2668 mode;
  2669 
  2670 * Pure/obtain: the formal conclusion "thesis", being marked as
  2671 ``internal'', may no longer be reference directly in the text;
  2672 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2673 situations;
  2674 
  2675 * Pure: generic 'sym' attribute which declares a rule both as pure
  2676 'elim?' and for the 'symmetric' operation;
  2677 
  2678 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2679 text; the fixed correlation with particular command syntax has been
  2680 discontinued;
  2681 
  2682 * Pure: new method 'rules' is particularly well-suited for proof
  2683 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2684 but often produces more compact proof terms with less detours;
  2685 
  2686 * Pure/Provers/classical: simplified integration with pure rule
  2687 attributes and methods; the classical "intro?/elim?/dest?"
  2688 declarations coincide with the pure ones; the "rule" method no longer
  2689 includes classically swapped intros; "intro" and "elim" methods no
  2690 longer pick rules from the context; also got rid of ML declarations
  2691 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2692 INCOMPATIBILITY;
  2693 
  2694 * Provers/classical: attribute 'swapped' produces classical inversions
  2695 of introduction rules;
  2696 
  2697 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2698 rules instead of full simplifier context; 'iff' attribute handles
  2699 conditional rules;
  2700 
  2701 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2702 
  2703 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2704 "(permissive)" option to recover old behavior;
  2705 
  2706 * HOL: 'inductive' no longer features separate (collective) attributes
  2707 for 'intros' (was found too confusing);
  2708 
  2709 * HOL: properly declared induction rules less_induct and
  2710 wf_induct_rule;
  2711 
  2712 
  2713 *** HOL ***
  2714 
  2715 * HOL: moved over to sane numeral syntax; the new policy is as
  2716 follows:
  2717 
  2718   - 0 and 1 are polymorphic constants, which are defined on any
  2719   numeric type (nat, int, real etc.);
  2720 
  2721   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2722   binary representation internally;
  2723 
  2724   - type nat has special constructor Suc, and generally prefers Suc 0
  2725   over 1::nat and Suc (Suc 0) over 2::nat;
  2726 
  2727 This change may cause significant problems of INCOMPATIBILITY; here
  2728 are some hints on converting existing sources:
  2729 
  2730   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2731   entities, so expressions involving "-" (unary or binary minus) need
  2732   to be spaced properly;
  2733 
  2734   - existing occurrences of "1" may need to be constraint "1::nat" or
  2735   even replaced by Suc 0; similar for old "2";
  2736 
  2737   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2738 
  2739   - remove all special provisions on numerals in proofs;
  2740 
  2741 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2742 representation (depends on bin_arith_simps in the default context);
  2743 
  2744 * HOL: symbolic syntax for x^2 (numeral 2);
  2745 
  2746 * HOL: the class of all HOL types is now called "type" rather than
  2747 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2748 in axclass/classes, instance/arities, and (usually rare) occurrences
  2749 in typings (of consts etc.); internally the class is called
  2750 "HOL.type", ML programs should refer to HOLogic.typeS;
  2751 
  2752 * HOL/record package improvements:
  2753   - new derived operations "fields" to build a partial record section,
  2754     "extend" to promote a fixed record to a record scheme, and
  2755     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2756     declared as simp by default;
  2757   - shared operations ("more", "fields", etc.) now need to be always
  2758     qualified) --- potential INCOMPATIBILITY;
  2759   - removed "make_scheme" operations (use "make" with "extend") --
  2760     INCOMPATIBILITY;
  2761   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2762   - provides cases/induct rules for use with corresponding Isar
  2763     methods (for concrete records, record schemes, concrete more
  2764     parts, and schematic more parts -- in that order);
  2765   - internal definitions directly based on a light-weight abstract
  2766     theory of product types over typedef rather than datatype;
  2767 
  2768 * HOL: generic code generator for generating executable ML code from
  2769 specifications; specific support for HOL constructs such as inductive
  2770 datatypes and sets, as well as recursive functions; can be invoked
  2771 via 'generate_code' theory section;
  2772 
  2773 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2774 
  2775 * HOL: consolidated and renamed several theories.  In particular:
  2776         Ord.thy has been absorbed into HOL.thy
  2777         String.thy has been absorbed into List.thy
  2778 
  2779 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2780 (beware of argument permutation!);
  2781 
  2782 * HOL: linorder_less_split superseded by linorder_cases;
  2783 
  2784 * HOL/List: "nodups" renamed to "distinct";
  2785 
  2786 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2787 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2788   - Ex_def has changed, now need to use some_eq_ex
  2789 
  2790 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2791 in this (rare) case use:
  2792 
  2793   delSWrapper "split_all_tac"
  2794   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2795 
  2796 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2797 MAY FAIL;
  2798 
  2799 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2800 Isabelle's type classes, ^ on functions and relations has too general
  2801 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2802 necessary to attach explicit type constraints;
  2803 
  2804 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2805 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2806 renamed accordingly (eg "compI" -> "rel_compI").
  2807 
  2808 * HOL: syntax translations now work properly with numerals and records
  2809 expressions;
  2810 
  2811 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2812 of "lam" -- INCOMPATIBILITY;
  2813 
  2814 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2815 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2816 renamed "Product_Type.unit";
  2817 
  2818 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2819 
  2820 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2821 the "cases" method);
  2822 
  2823 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2824 Florian Kammller);
  2825 
  2826 * HOL/IMP: updated and converted to new-style theory format; several
  2827 parts turned into readable document, with proper Isar proof texts and
  2828 some explanations (by Gerwin Klein);
  2829 
  2830 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2831 
  2832 * HOL-Hyperreal is now a logic image;
  2833 
  2834 
  2835 *** HOLCF ***
  2836 
  2837 * Isar: consts/constdefs supports mixfix syntax for continuous
  2838 operations;
  2839 
  2840 * Isar: domain package adapted to new-style theory format, e.g. see
  2841 HOLCF/ex/Dnat.thy;
  2842 
  2843 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2844 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2845 lift.induct_tac, always use UU instead of Undef;
  2846 
  2847 * HOLCF/IMP: updated and converted to new-style theory;
  2848 
  2849 
  2850 *** ZF ***
  2851 
  2852 * Isar: proper integration of logic-specific tools and packages,
  2853 including theory commands '(co)inductive', '(co)datatype',
  2854 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2855 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2856 
  2857 * theory Main no longer includes AC; for the Axiom of Choice, base
  2858 your theory on Main_ZFC;
  2859 
  2860 * the integer library now covers quotients and remainders, with many
  2861 laws relating division to addition, multiplication, etc.;
  2862 
  2863 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2864 typeless version of the formalism;
  2865 
  2866 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2867 format;
  2868 
  2869 * ZF/Induct: new directory for examples of inductive definitions,
  2870 including theory Multiset for multiset orderings; converted to
  2871 new-style theory format;
  2872 
  2873 * ZF: many new theorems about lists, ordinals, etc.;
  2874 
  2875 
  2876 *** General ***
  2877 
  2878 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2879 variable proof controls level of detail: 0 = no proofs (only oracle
  2880 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2881 also ref manual for further ML interfaces;
  2882 
  2883 * Pure/axclass: removed obsolete ML interface
  2884 goal_subclass/goal_arity;
  2885 
  2886 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2887 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2888 separate tokens, so expressions involving minus need to be spaced
  2889 properly;
  2890 
  2891 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2892 rather than "infixl" or "infixr";
  2893 
  2894 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2895 sort constraint specifications in type inference; e.g. "x::_::foo"
  2896 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2897 type variable);
  2898 
  2899 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2900 control output of nested => (types); the default behavior is
  2901 "type_brackets";
  2902 
  2903 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2904 tokens into AST constants;
  2905 
  2906 * Pure/syntax: prefer later declarations of translations and print
  2907 translation functions; potential INCOMPATIBILITY: need to reverse
  2908 multiple declarations for same syntax element constant;
  2909 
  2910 * Pure/show_hyps reset by default (in accordance to existing Isar
  2911 practice);
  2912 
  2913 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2914 addSafter;
  2915 
  2916 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2917 as well;
  2918 
  2919 * system: tested support for MacOS X; should be able to get Isabelle +
  2920 Proof General to work in a plain Terminal after installing Poly/ML
  2921 (e.g. from the Isabelle distribution area) and GNU bash alone
  2922 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2923 support requires further installations, e.g. from
  2924 http://fink.sourceforge.net/);
  2925 
  2926 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2927 
  2928 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2929 of 40 MB), cf. ML_OPTIONS;
  2930 
  2931 * system: Proof General keywords specification is now part of the
  2932 Isabelle distribution (see etc/isar-keywords.el);
  2933 
  2934 * system: support for persistent Proof General sessions (refrain from
  2935 outdating all loaded theories on startup); user may create writable
  2936 logic images like this: ``isabelle -q HOL Test'';
  2937 
  2938 * system: smart selection of Isabelle process versus Isabelle
  2939 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2940 run both "isabelle" and "Isabelle" even if file names are badly
  2941 damaged (executable inspects the case of the first letter of its own
  2942 name); added separate "isabelle-process" and "isabelle-interface";
  2943 
  2944 * system: refrain from any attempt at filtering input streams; no
  2945 longer support ``8bit'' encoding of old isabelle font, instead proper
  2946 iso-latin characters may now be used; the related isatools
  2947 "symbolinput" and "nonascii" have disappeared as well;
  2948 
  2949 * system: removed old "xterm" interface (the print modes "xterm" and
  2950 "xterm_color" are still available for direct use in a suitable
  2951 terminal);
  2952 
  2953 
  2954 
  2955 New in Isabelle99-2 (February 2001)
  2956 -----------------------------------
  2957 
  2958 *** Overview of INCOMPATIBILITIES ***
  2959 
  2960 * HOL: please note that theories in the Library and elsewhere often use the
  2961 new-style (Isar) format; to refer to their theorems in an ML script you must
  2962 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2963 
  2964 * HOL: inductive package no longer splits induction rule aggressively,
  2965 but only as far as specified by the introductions given; the old
  2966 format may be recovered via ML function complete_split_rule or attribute
  2967 'split_rule (complete)';
  2968 
  2969 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2970 gfp_Tarski to gfp_unfold;
  2971 
  2972 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2973 
  2974 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2975 relation); infix "^^" has been renamed "``"; infix "``" has been
  2976 renamed "`"; "univalent" has been renamed "single_valued";
  2977 
  2978 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2979 operation;
  2980 
  2981 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2982 
  2983 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2984 
  2985 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2986 consequence, it is no longer monotonic wrt. the local goal context
  2987 (which is now passed through the inductive cases);
  2988 
  2989 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2990 \<gg> to \<ggreater>;
  2991 
  2992 
  2993 *** Document preparation ***
  2994 
  2995 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2996 available: are "it" for near math-mode best-style output, "sl" for
  2997 slanted text style, and "tt" for plain type-writer; if no
  2998 \isabellestyle command is given, output is according to slanted
  2999 type-writer);
  3000 
  3001 * support sub/super scripts (for single symbols only), input syntax is
  3002 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3003 
  3004 * some more standard symbols; see Appendix A of the system manual for
  3005 the complete list of symbols defined in isabellesym.sty;
  3006 
  3007 * improved isabelle style files; more abstract symbol implementation
  3008 (should now use \isamath{...} and \isatext{...} in custom symbol
  3009 definitions);
  3010 
  3011 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3012 state; Note that presentation of goal states does not conform to
  3013 actual human-readable proof documents.  Please do not include goal
  3014 states into document output unless you really know what you are doing!
  3015 
  3016 * proper indentation of antiquoted output with proportional LaTeX
  3017 fonts;
  3018 
  3019 * no_document ML operator temporarily disables LaTeX document
  3020 generation;
  3021 
  3022 * isatool unsymbolize tunes sources for plain ASCII communication;
  3023 
  3024 
  3025 *** Isar ***
  3026 
  3027 * Pure: Isar now suffers initial goal statements to contain unbound
  3028 schematic variables (this does not conform to actual readable proof
  3029 documents, due to unpredictable outcome and non-compositional proof
  3030 checking); users who know what they are doing may use schematic goals
  3031 for Prolog-style synthesis of proven results;
  3032 
  3033 * Pure: assumption method (an implicit finishing) now handles actual
  3034 rules as well;
  3035 
  3036 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3037 initial goal, declare "that" only as Pure intro (only for single
  3038 steps); the "that" rule assumption may now be involved in implicit
  3039 finishing, thus ".." becomes a feasible for trivial obtains;
  3040 
  3041 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3042 instance proofs may be performed by "..";
  3043 
  3044 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3045 statements as well;
  3046 
  3047 * Pure: more robust selection of calculational rules;
  3048 
  3049 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3050 rule (as well as the assumption rule);
  3051 
  3052 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3053 lemmas, using the graph browser tool;
  3054 
  3055 * Pure: predict failure of "show" in interactive mode;
  3056 
  3057 * Pure: 'thms_containing' now takes actual terms as arguments;
  3058 
  3059 * HOL: improved method 'induct' --- now handles non-atomic goals
  3060 (potential INCOMPATIBILITY); tuned error handling;
  3061 
  3062 * HOL: cases and induct rules now provide explicit hints about the
  3063 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3064 any remaining facts are inserted into the goal verbatim;
  3065 
  3066 * HOL: local contexts (aka cases) may now contain term bindings as
  3067 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3068 the result to be shown in each case;
  3069 
  3070 * HOL: added 'recdef_tc' command;
  3071 
  3072 * isatool convert assists in eliminating legacy ML scripts;
  3073 
  3074 
  3075 *** HOL ***
  3076 
  3077 * HOL/Library: a collection of generic theories to be used together
  3078 with main HOL; the theory loader path already includes this directory
  3079 by default; the following existing theories have been moved here:
  3080 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3081 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3082 
  3083 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3084 modelling and verification task performed in Isabelle/HOL +
  3085 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3086 
  3087 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3088 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3089 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3090 'domain', this makes the theory consistent with mathematical
  3091 literature;
  3092 
  3093 * HOL basics: added overloaded operations "inverse" and "divide"
  3094 (infix "/"), syntax for generic "abs" operation, generic summation
  3095 operator \<Sum>;
  3096 
  3097 * HOL/typedef: simplified package, provide more useful rules (see also
  3098 HOL/subset.thy);
  3099 
  3100 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3101 now expressed as a proper nested rule (old-style tactic scripts may
  3102 require atomize_strip_tac to cope with non-atomic premises);
  3103 
  3104 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3105 to "split_conv" (old name still available for compatibility);
  3106 
  3107 * HOL: improved concrete syntax for strings (e.g. allows translation
  3108 rules with string literals);
  3109 
  3110 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3111  and Fleuriot's mechanization of analysis, including the transcendental
  3112  functions for the reals;
  3113 
  3114 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3115 
  3116 
  3117 *** CTT ***
  3118 
  3119 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3120 "lam" is displayed as TWO lambda-symbols
  3121 
  3122 * CTT: theory Main now available, containing everything (that is, Bool
  3123 and Arith);
  3124 
  3125 
  3126 *** General ***
  3127 
  3128 * Pure: the Simplifier has been implemented properly as a derived rule
  3129 outside of the actual kernel (at last!); the overall performance
  3130 penalty in practical applications is about 50%, while reliability of
  3131 the Isabelle inference kernel has been greatly improved;
  3132 
  3133 * print modes "brackets" and "no_brackets" control output of nested =>
  3134 (types) and ==> (props); the default behaviour is "brackets";
  3135 
  3136 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3137 as assumptions as well;
  3138 
  3139 * system: support Poly/ML 4.0;
  3140 
  3141 * system: isatool install handles KDE version 1 or 2;
  3142 
  3143 
  3144 
  3145 New in Isabelle99-1 (October 2000)
  3146 ----------------------------------
  3147 
  3148 *** Overview of INCOMPATIBILITIES ***
  3149 
  3150 * HOL: simplification of natural numbers is much changed; to partly
  3151 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3152 issue the following ML commands:
  3153 
  3154   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3155   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3156 
  3157 * HOL: simplification no longer dives into case-expressions; this is
  3158 controlled by "t.weak_case_cong" for each datatype t;
  3159 
  3160 * HOL: nat_less_induct renamed to less_induct;
  3161 
  3162 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3163 fixsome to patch .thy and .ML sources automatically;
  3164 
  3165   select_equality  -> some_equality
  3166   select_eq_Ex     -> some_eq_ex
  3167   selectI2EX       -> someI2_ex
  3168   selectI2         -> someI2
  3169   selectI          -> someI
  3170   select1_equality -> some1_equality
  3171   Eps_sym_eq       -> some_sym_eq_trivial
  3172   Eps_eq           -> some_eq_trivial
  3173 
  3174 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3175 
  3176 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3177 instead);
  3178 
  3179 * HOL: the recursion equations generated by 'recdef' are now called
  3180 f.simps instead of f.rules;
  3181 
  3182 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3183 
  3184 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3185 sometimes be needed;
  3186 
  3187 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3188 
  3189 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3190 
  3191 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3192 product is now "<*>" instead of "Times"; the lexicographic product is
  3193 now "<*lex*>" instead of "**";
  3194 
  3195 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3196 of main HOL, but was unused); better use HOL's datatype package;
  3197 
  3198 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3199 the old syntax may be recovered as follows:
  3200 
  3201   syntax (symbols)
  3202     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3203       (infixl "\\<oplus>" 100)
  3204 
  3205 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3206 
  3207 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3208 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3209 internally;
  3210 
  3211 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3212 changed from A/r to A//r;
  3213 
  3214 * ZF: new treatment of arithmetic (nat & int) may break some old
  3215 proofs;
  3216 
  3217 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3218 rulify -> rule_format, elimify -> elim_format, ...);
  3219 
  3220 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3221 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3222 should have to change intro!! to intro? only); replaced "delrule" by
  3223 "rule del";
  3224 
  3225 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3226 
  3227 * Provers: strengthened force_tac by using new first_best_tac;
  3228 
  3229 * LaTeX document preparation: several changes of isabelle.sty (see
  3230 lib/texinputs);
  3231 
  3232 
  3233 *** Document preparation ***
  3234 
  3235 * formal comments (text blocks etc.) in new-style theories may now
  3236 contain antiquotations of thm/prop/term/typ/text to be presented
  3237 according to latex print mode; concrete syntax is like this:
  3238 @{term[show_types] "f(x) = a + x"};
  3239 
  3240 * isatool mkdir provides easy setup of Isabelle session directories,
  3241 including proper document sources;
  3242 
  3243 * generated LaTeX sources are now deleted after successful run
  3244 (isatool document -c); may retain a copy somewhere else via -D option
  3245 of isatool usedir;
  3246 
  3247 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3248 style files, achieving self-contained LaTeX sources and simplifying
  3249 LaTeX debugging;
  3250 
  3251 * old-style theories now produce (crude) LaTeX output as well;
  3252 
  3253 * browser info session directories are now self-contained (may be put
  3254 on WWW server seperately); improved graphs of nested sessions; removed
  3255 graph for 'all sessions';
  3256 
  3257 * several improvements in isabelle style files; \isabellestyle{it}
  3258 produces fake math mode output; \isamarkupheader is now \section by
  3259 default; see lib/texinputs/isabelle.sty etc.;
  3260 
  3261 
  3262 *** Isar ***
  3263 
  3264 * Isar/Pure: local results and corresponding term bindings are now
  3265 subject to Hindley-Milner polymorphism (similar to ML); this
  3266 accommodates incremental type-inference very nicely;
  3267 
  3268 * Isar/Pure: new derived language element 'obtain' supports
  3269 generalized existence reasoning;
  3270 
  3271 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3272 support accumulation of results, without applying any rules yet;
  3273 useful to collect intermediate results without explicit name
  3274 references, and for use with transitivity rules with more than 2
  3275 premises;
  3276 
  3277 * Isar/Pure: scalable support for case-analysis type proofs: new
  3278 'case' language element refers to local contexts symbolically, as
  3279 produced by certain proof methods; internally, case names are attached
  3280 to theorems as "tags";
  3281 
  3282 * Isar/Pure: theory command 'hide' removes declarations from
  3283 class/type/const name spaces;
  3284 
  3285 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3286 indicate potential overloading;
  3287 
  3288 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3289 
  3290 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3291 "{a,b,c}" instead of {a,b,c};
  3292 
  3293 * Isar/Pure now provides its own version of intro/elim/dest
  3294 attributes; useful for building new logics, but beware of confusion
  3295 with the version in Provers/classical;
  3296 
  3297 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3298 case name 'antecedent';
  3299 
  3300 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3301 to the current context is now done automatically);
  3302 
  3303 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3304 for definining proof methods in ML;
  3305 
  3306 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3307 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3308 most cases, one should have to change intro!! to intro? only);
  3309 replaced "delrule" by "rule del";
  3310 
  3311 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3312 'symmetric' attribute (the latter supercedes [RS sym]);
  3313 
  3314 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3315 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3316 well (including splits);
  3317 
  3318 * Isar/Provers: Simplifier and Classical methods now support all kind
  3319 of modifiers used in the past, including 'cong', 'iff', etc.
  3320 
  3321 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3322 of Simplifier and Classical reasoner);
  3323 
  3324 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3325 now support named cases; major packages (inductive, datatype, primrec,
  3326 recdef) support case names and properly name parameters;
  3327 
  3328 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3329 monotonicity conditions are extracted to be proven at end of
  3330 calculations;
  3331 
  3332 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3333 method anyway;
  3334 
  3335 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3336 split_if split_if_asm; datatype package provides theorems foo.splits =
  3337 foo.split foo.split_asm for each datatype;
  3338 
  3339 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3340 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3341 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3342 use "(cases (simplified))" method in proper proof texts);
  3343 
  3344 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3345 
  3346 * Isar: names of theorems etc. may be natural numbers as well;
  3347 
  3348 * Isar: 'pr' command: optional arguments for goals_limit and
  3349 ProofContext.prems_limit; no longer prints theory contexts, but only
  3350 proof states;
  3351 
  3352 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3353 additional print modes to be specified; e.g. "pr(latex)" will print
  3354 proof state according to the Isabelle LaTeX style;
  3355 
  3356 * Isar: improved support for emulating tactic scripts, including proof
  3357 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3358 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3359 (for HOL datatypes);
  3360 
  3361 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3362 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3363 'proof method scripts' have to be in depth-first order;
  3364 
  3365 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3366 
  3367 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3368 should instead use individual commands for printing items
  3369 (print_commands, print_methods etc.);
  3370 
  3371 * Isar: added 'nothing' --- the empty list of theorems;
  3372 
  3373 
  3374 *** HOL ***
  3375 
  3376 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3377 corresponding virtual machine and a specification of its bytecode
  3378 verifier and a lightweight bytecode verifier, including proofs of
  3379 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3380 Cornelia Pusch (see also the homepage of project Bali at
  3381 http://isabelle.in.tum.de/Bali/);
  3382 
  3383 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3384 Clemens Ballarin;
  3385 
  3386 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3387 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3388 Rasmussen;
  3389 
  3390 * HOL/Lattice: fundamental concepts of lattice theory and order
  3391 structures, including duals, properties of bounds versus algebraic
  3392 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3393 Theorem for complete lattices etc.; may also serve as a demonstration
  3394 for abstract algebraic reasoning using axiomatic type classes, and
  3395 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3396 
  3397 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3398 von Oheimb;
  3399 
  3400 * HOL/IMPP: extension of IMP with local variables and mutually
  3401 recursive procedures, by David von Oheimb;
  3402 
  3403 * HOL/Lambda: converted into new-style theory and document;
  3404 
  3405 * HOL/ex/Multiquote: example of multiple nested quotations and
  3406 anti-quotations -- basically a generalized version of de-Bruijn
  3407 representation; very useful in avoiding lifting of operations;
  3408 
  3409 * HOL/record: added general record equality rule to simpset; fixed
  3410 select-update simplification procedure to handle extended records as
  3411 well; admit "r" as field name;
  3412 
  3413 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3414 other numeric types and also as the identity of groups, rings, etc.;
  3415 
  3416 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3417 Types nat and int belong to this axclass;
  3418 
  3419 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3420    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3421    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3422   two terms #m*u and #n*u are replaced by #(m+n)*u
  3423     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3424   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3425     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3426 
  3427 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3428 powerful prover for predicate logic but knows nothing of clasets; see
  3429 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3430 
  3431 * HOL: new version of "case_tac" subsumes both boolean case split and
  3432 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3433 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3434 
  3435 * HOL: simplification no longer dives into case-expressions: only the
  3436 selector expression is simplified, but not the remaining arms; to
  3437 enable full simplification of case-expressions for datatype t, you may
  3438 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3439 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3440 
  3441 * HOL/recdef: the recursion equations generated by 'recdef' for
  3442 function 'f' are now called f.simps instead of f.rules; if all
  3443 termination conditions are proved automatically, these simplification
  3444 rules are added to the simpset, as in primrec; rules may be named
  3445 individually as well, resulting in a separate list of theorems for
  3446 each equation;
  3447 
  3448 * HOL/While is a new theory that provides a while-combinator. It
  3449 permits the definition of tail-recursive functions without the
  3450 provision of a termination measure. The latter is necessary once the
  3451 invariant proof rule for while is applied.
  3452 
  3453 * HOL: new (overloaded) notation for the set of elements below/above
  3454 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3455 
  3456 * HOL: theorems impI, allI, ballI bound as "strip";
  3457 
  3458 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3459 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3460 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3461 
  3462 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3463 
  3464 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3465 main HOL, but was unused);
  3466 
  3467 * HOL: fewer consts declared as global (e.g. have to refer to
  3468 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3469 
  3470 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3471 in case of overlap with user translations (e.g. judgements over
  3472 tuples); (note that the underlying logical represenation is still
  3473 bogus);
  3474 
  3475 
  3476 *** ZF ***
  3477 
  3478 * ZF: simplification automatically cancels common terms in arithmetic
  3479 expressions over nat and int;
  3480 
  3481 * ZF: new treatment of nat to minimize type-checking: all operators
  3482 coerce their operands to a natural number using the function natify,
  3483 making the algebraic laws unconditional;
  3484 
  3485 * ZF: as above, for int: operators coerce their operands to an integer
  3486 using the function intify;
  3487 
  3488 * ZF: the integer library now contains many of the usual laws for the
  3489 orderings, including $<=, and monotonicity laws for $+ and $*;
  3490 
  3491 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3492 simplification;
  3493 
  3494 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3495 to the simplifier and classical reasoner simultaneously;
  3496 
  3497 
  3498 *** General ***
  3499 
  3500 * Provers: blast_tac now handles actual object-logic rules as
  3501 assumptions; note that auto_tac uses blast_tac internally as well;
  3502 
  3503 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3504 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3505 
  3506 * Provers: delrules now handles destruct rules as well (no longer need
  3507 explicit make_elim);
  3508 
  3509 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3510   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3511 use instead the strong form,
  3512   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3513 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3514 from destruct-rules;
  3515 
  3516 * Provers: Simplifier.easy_setup provides a fast path to basic
  3517 Simplifier setup for new object-logics;
  3518 
  3519 * Pure: AST translation rules no longer require constant head on LHS;
  3520 
  3521 * Pure: improved name spaces: ambiguous output is qualified; support
  3522 for hiding of names;
  3523 
  3524 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3525 XSYMBOL_HOME; no longer need to do manual configuration in most
  3526 situations;
  3527 
  3528 * system: compression of ML heaps images may now be controlled via -c
  3529 option of isabelle and isatool usedir (currently only observed by
  3530 Poly/ML);
  3531 
  3532 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3533 useful for remote X11);
  3534 
  3535 * system: provide TAGS file for Isabelle sources;
  3536 
  3537 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3538 order;
  3539 
  3540 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3541 timing flag supersedes proof_timing and Toplevel.trace;
  3542 
  3543 * ML: new combinators |>> and |>>> for incremental transformations
  3544 with secondary results (e.g. certain theory extensions):
  3545 
  3546 * ML: PureThy.add_defs gets additional argument to indicate potential
  3547 overloading (usually false);
  3548 
  3549 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3550 results;
  3551 
  3552 
  3553 
  3554 New in Isabelle99 (October 1999)
  3555 --------------------------------
  3556 
  3557 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3558 
  3559 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3560 are no longer simplified.  (This allows the simplifier to unfold recursive
  3561 functional programs.)  To restore the old behaviour, declare
  3562 
  3563     Delcongs [if_weak_cong];
  3564 
  3565 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3566 complement;
  3567 
  3568 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3569 
  3570 * HOL/datatype: mutual_induct_tac no longer exists --
  3571   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3572 
  3573 * HOL/typedef: fixed type inference for representing set; type
  3574 arguments now have to occur explicitly on the rhs as type constraints;
  3575 
  3576 * ZF: The con_defs part of an inductive definition may no longer refer
  3577 to constants declared in the same theory;
  3578 
  3579 * HOL, ZF: the function mk_cases, generated by the inductive
  3580 definition package, has lost an argument.  To simplify its result, it
  3581 uses the default simpset instead of a supplied list of theorems.
  3582 
  3583 * HOL/List: the constructors of type list are now Nil and Cons;
  3584 
  3585 * Simplifier: the type of the infix ML functions
  3586         setSSolver addSSolver setSolver addSolver
  3587 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3588 for packaging solvers. A solver is created via
  3589         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3590 where the string argument is only a comment.
  3591 
  3592 
  3593 *** Proof tools ***
  3594 
  3595 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3596 decision procedure for linear arithmetic. Currently it is used for
  3597 types `nat', `int', and `real' in HOL (see below); it can, should and
  3598 will be instantiated for other types and logics as well.
  3599 
  3600 * The simplifier now accepts rewrite rules with flexible heads, eg
  3601      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3602   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3603   matching.
  3604 
  3605 
  3606 *** General ***
  3607 
  3608 * New Isabelle/Isar subsystem provides an alternative to traditional
  3609 tactical theorem proving; together with the ProofGeneral/isar user
  3610 interface it offers an interactive environment for developing human
  3611 readable proof documents (Isar == Intelligible semi-automated
  3612 reasoning); for further information see isatool doc isar-ref,
  3613 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3614 
  3615 * improved and simplified presentation of theories: better HTML markup
  3616 (including colors), graph views in several sizes; isatool usedir now
  3617 provides a proper interface for user theories (via -P option); actual
  3618 document preparation based on (PDF)LaTeX is available as well (for
  3619 new-style theories only); see isatool doc system for more information;
  3620 
  3621 * native support for Proof General, both for classic Isabelle and
  3622 Isabelle/Isar;
  3623 
  3624 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3625 using the graph browser tool;
  3626 
  3627 * Isabelle manuals now also available as PDF;
  3628 
  3629 * theory loader rewritten from scratch (may not be fully
  3630 bug-compatible); old loadpath variable has been replaced by show_path,
  3631 add_path, del_path, reset_path functions; new operations such as
  3632 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3633 isatool doc ref);
  3634 
  3635 * improved isatool install: option -k creates KDE application icon,
  3636 option -p DIR installs standalone binaries;
  3637 
  3638 * added ML_PLATFORM setting (useful for cross-platform installations);
  3639 more robust handling of platform specific ML images for SML/NJ;
  3640 
  3641 * the settings environment is now statically scoped, i.e. it is never
  3642 created again in sub-processes invoked from isabelle, isatool, or
  3643 Isabelle;
  3644 
  3645 * path element specification '~~' refers to '$ISABELLE_HOME';
  3646 
  3647 * in locales, the "assumes" and "defines" parts may be omitted if
  3648 empty;
  3649 
  3650 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3651 long arrows);
  3652 
  3653 * new print_mode "HTML";
  3654 
  3655 * new flag show_tags controls display of tags of theorems (which are
  3656 basically just comments that may be attached by some tools);
  3657 
  3658 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3659 mode and goal output format:
  3660 
  3661 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3662 244c244
  3663 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3664 ---
  3665 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3666 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3667 181c181
  3668 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3669 ---
  3670 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3671 
  3672 * function bind_thms stores lists of theorems (cf. bind_thm);
  3673 
  3674 * new shorthand tactics ftac, eatac, datac, fatac;
  3675 
  3676 * qed (and friends) now accept "" as result name; in that case the
  3677 theorem is not stored, but proper checks and presentation of the
  3678 result still apply;
  3679 
  3680 * theorem database now also indexes constants "Trueprop", "all",
  3681 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3682 
  3683 
  3684 *** HOL ***
  3685 
  3686 ** HOL arithmetic **
  3687 
  3688 * There are now decision procedures for linear arithmetic over nat and
  3689 int:
  3690 
  3691 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3692 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3693 are treated as atomic; subformulae not involving type `nat' or `int'
  3694 are ignored; quantified subformulae are ignored unless they are
  3695 positive universal or negative existential. The tactic has to be
  3696 invoked by hand and can be a little bit slow. In particular, the
  3697 running time is exponential in the number of occurrences of `min' and
  3698 `max', and `-' on `nat'.
  3699 
  3700 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3701 (negated) (in)equalities among the premises and the conclusion into
  3702 account (i.e. no compound formulae) and does not know about `min' and
  3703 `max', and `-' on `nat'. It is fast and is used automatically by the
  3704 simplifier.
  3705 
  3706 NB: At the moment, these decision procedures do not cope with mixed
  3707 nat/int formulae where the two parts interact, such as `m < n ==>
  3708 int(m) < int(n)'.
  3709 
  3710 * HOL/Numeral provides a generic theory of numerals (encoded
  3711 efficiently as bit strings); setup for types nat/int/real is in place;
  3712 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3713 int, existing theories and proof scripts may require a few additional
  3714 type constraints;
  3715 
  3716 * integer division and remainder can now be performed on constant
  3717 arguments;
  3718 
  3719 * many properties of integer multiplication, division and remainder
  3720 are now available;
  3721 
  3722 * An interface to the Stanford Validity Checker (SVC) is available through the
  3723 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3724 are proved automatically.  SVC must be installed separately, and its results
  3725 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3726 invocation of the underlying oracle).  For SVC see
  3727   http://verify.stanford.edu/SVC
  3728 
  3729 * IsaMakefile: the HOL-Real target now builds an actual image;
  3730 
  3731 
  3732 ** HOL misc **
  3733 
  3734 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3735 (in Isabelle/Isar) -- by Gertrud Bauer;
  3736 
  3737 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3738 analysis for assembly languages with subtypes;
  3739 
  3740 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3741 -- avoids syntactic ambiguities and treats state, transition, and
  3742 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3743 changed syntax and (many) tactics;
  3744 
  3745 * HOL/inductive: Now also handles more general introduction rules such
  3746   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3747   theorems are now maintained within the theory (maintained via the
  3748   "mono" attribute);
  3749 
  3750 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3751   (using function types) such as
  3752 
  3753   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3754 
  3755 * HOL/record: record_simproc (part of the default simpset) takes care
  3756 of selectors applied to updated records; record_split_tac is no longer
  3757 part of the default claset; update_defs may now be removed from the
  3758 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3759 
  3760   claset_ref () := claset() addSWrapper record_split_wrapper;
  3761   Delsimprocs [record_simproc]
  3762 
  3763 * HOL/typedef: fixed type inference for representing set; type
  3764 arguments now have to occur explicitly on the rhs as type constraints;
  3765 
  3766 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3767 names rather than an ML expression;
  3768 
  3769 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3770 supplied later.  Program schemes can be defined, such as
  3771     "While B C s = (if B s then While B C (C s) else s)"
  3772 where the well-founded relation can be chosen after B and C have been given.
  3773 
  3774 * HOL/List: the constructors of type list are now Nil and Cons;
  3775 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3776 course, ML tools referring to List.list.op # etc. have to be adapted;
  3777 
  3778 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3779 disabled by default; run isabelle with option -m HOL to get back to
  3780 the original Gordon/HOL-style output;
  3781 
  3782 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3783 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3784 
  3785 * HOL basic syntax simplified (more orthogonal): all variants of
  3786 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3787 Eps operator is provided as well: "SOME x. P[x]";
  3788 
  3789 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3790 
  3791 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3792 thus available for user theories;
  3793 
  3794 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3795 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3796 time;
  3797 
  3798 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3799 several times and then mp;
  3800 
  3801 
  3802 *** LK ***
  3803 
  3804 * the notation <<...>> is now available as a notation for sequences of
  3805 formulas;
  3806 
  3807 * the simplifier is now installed
  3808 
  3809 * the axiom system has been generalized (thanks to Soren Heilmann)
  3810 
  3811 * the classical reasoner now has a default rule database
  3812 
  3813 
  3814 *** ZF ***
  3815 
  3816 * new primrec section allows primitive recursive functions to be given
  3817 directly (as in HOL) over datatypes and the natural numbers;
  3818 
  3819 * new tactics induct_tac and exhaust_tac for induction (or case
  3820 analysis) over datatypes and the natural numbers;
  3821 
  3822 * the datatype declaration of type T now defines the recursor T_rec;
  3823 
  3824 * simplification automatically does freeness reasoning for datatype
  3825 constructors;
  3826 
  3827 * automatic type-inference, with AddTCs command to insert new
  3828 type-checking rules;
  3829 
  3830 * datatype introduction rules are now added as Safe Introduction rules
  3831 to the claset;
  3832 
  3833 * the syntax "if P then x else y" is now available in addition to
  3834 if(P,x,y);
  3835 
  3836 
  3837 *** Internal programming interfaces ***
  3838 
  3839 * tuned simplifier trace output; new flag debug_simp;
  3840 
  3841 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3842 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3843 
  3844 * AxClass.axclass_tac lost the theory argument;
  3845 
  3846 * tuned current_goals_markers semantics: begin / end goal avoids
  3847 printing empty lines;
  3848 
  3849 * removed prs and prs_fn hook, which was broken because it did not
  3850 include \n in its semantics, forcing writeln to add one
  3851 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3852 string -> unit if you really want to output text without newline;
  3853 
  3854 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3855 plain output, interface builders may have to enable 'isabelle_font'
  3856 mode to get Isabelle font glyphs as before;
  3857 
  3858 * refined token_translation interface; INCOMPATIBILITY: output length
  3859 now of type real instead of int;
  3860 
  3861 * theory loader actions may be traced via new ThyInfo.add_hook
  3862 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3863 your own database of information attached to *whole* theories -- as
  3864 opposed to intra-theory data slots offered via TheoryDataFun;
  3865 
  3866 * proper handling of dangling sort hypotheses (at last!);
  3867 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3868 extra sort hypotheses that can be witnessed from the type signature;
  3869 the force_strip_shyps flag is gone, any remaining shyps are simply
  3870 left in the theorem (with a warning issued by strip_shyps_warning);
  3871 
  3872 
  3873 
  3874 New in Isabelle98-1 (October 1998)
  3875 ----------------------------------
  3876 
  3877 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3878 
  3879 * several changes of automated proof tools;
  3880 
  3881 * HOL: major changes to the inductive and datatype packages, including
  3882 some minor incompatibilities of theory syntax;
  3883 
  3884 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3885 called `inj_on';
  3886 
  3887 * HOL: removed duplicate thms in Arith:
  3888   less_imp_add_less  should be replaced by  trans_less_add1
  3889   le_imp_add_le      should be replaced by  trans_le_add1
  3890 
  3891 * HOL: unary minus is now overloaded (new type constraints may be
  3892 required);
  3893 
  3894 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3895 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3896 now taken as an integer constant.
  3897 
  3898 * Pure: ML function 'theory_of' renamed to 'theory';
  3899 
  3900 
  3901 *** Proof tools ***
  3902 
  3903 * Simplifier:
  3904   1. Asm_full_simp_tac is now more aggressive.
  3905      1. It will sometimes reorient premises if that increases their power to
  3906         simplify.
  3907      2. It does no longer proceed strictly from left to right but may also
  3908         rotate premises to achieve further simplification.
  3909      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3910      old Asm_full_simp_tac in that it does not rotate premises.
  3911   2. The simplifier now knows a little bit about nat-arithmetic.
  3912 
  3913 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3914 allows for selected deletion of wrappers, by introduction of names for
  3915 wrapper functionals.  This implies that addbefore, addSbefore,
  3916 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3917 and that adding two tactics with the same name overwrites the first
  3918 one (emitting a warning).
  3919   type wrapper = (int -> tactic) -> (int -> tactic)
  3920   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3921   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3922   delWrapper, delSWrapper: claset *  string            -> claset
  3923   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3924 
  3925 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3926 semantics; addbefore now affects only the unsafe part of step_tac
  3927 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3928 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3929 by Force_tac;
  3930 
  3931 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3932 compWrapper; added safe wrapper (and access functions for it);
  3933 
  3934 * HOL/split_all_tac is now much faster and fails if there is nothing
  3935 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3936 and the names of the automatically generated variables have changed.
  3937 split_all_tac has moved within claset() from unsafe wrappers to safe
  3938 wrappers, which means that !!-bound variables are split much more
  3939 aggressively, and safe_tac and clarify_tac now split such variables.
  3940 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3941 Note: the same holds for record_split_tac, which does the job of
  3942 split_all_tac for record fields.
  3943 
  3944 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3945 permanently to the default simpset using Addsplits just like
  3946 Addsimps. They can be removed via Delsplits just like
  3947 Delsimps. Lower-case versions are also available.
  3948 
  3949 * HOL/Simplifier: The rule split_if is now part of the default
  3950 simpset. This means that the simplifier will eliminate all occurrences
  3951 of if-then-else in the conclusion of a goal. To prevent this, you can
  3952 either remove split_if completely from the default simpset by
  3953 `Delsplits [split_if]' or remove it in a specific call of the
  3954 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3955 other case splitting rules to/from the default simpset: every datatype
  3956 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3957 t is the name of the datatype).
  3958 
  3959 * Classical reasoner / Simplifier combination: new force_tac (and
  3960 derivatives Force_tac, force) combines rewriting and classical
  3961 reasoning (and whatever other tools) similarly to auto_tac, but is
  3962 aimed to solve the given subgoal completely.
  3963 
  3964 
  3965 *** General ***
  3966 
  3967 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3968 and `goalw': the theory is no longer needed as an explicit argument -
  3969 the current theory context is used; assumptions are no longer returned
  3970 at the ML-level unless one of them starts with ==> or !!; it is
  3971 recommended to convert to these new commands using isatool fixgoal
  3972 (backup your sources first!);
  3973 
  3974 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3975 the current theory context, and 'theory' to lookup stored theories;
  3976 
  3977 * new theory section 'locale' for declaring constants, assumptions and
  3978 definitions that have local scope;
  3979 
  3980 * new theory section 'nonterminals' for purely syntactic types;
  3981 
  3982 * new theory section 'setup' for generic ML setup functions
  3983 (e.g. package initialization);
  3984 
  3985 * the distribution now includes Isabelle icons: see
  3986 lib/logo/isabelle-{small,tiny}.xpm;
  3987 
  3988 * isatool install - install binaries with absolute references to
  3989 ISABELLE_HOME/bin;
  3990 
  3991 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3992 
  3993 * print mode 'emacs' reserved for Isamode;
  3994 
  3995 * support multiple print (ast) translations per constant name;
  3996 
  3997 * theorems involving oracles are now printed with a suffixed [!];
  3998 
  3999 
  4000 *** HOL ***
  4001 
  4002 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4003 
  4004 * HOL/inductive package reorganized and improved: now supports mutual
  4005 definitions such as
  4006 
  4007   inductive EVEN ODD
  4008     intrs
  4009       null "0 : EVEN"
  4010       oddI "n : EVEN ==> Suc n : ODD"
  4011       evenI "n : ODD ==> Suc n : EVEN"
  4012 
  4013 new theorem list "elims" contains an elimination rule for each of the
  4014 recursive sets; inductive definitions now handle disjunctive premises
  4015 correctly (also ZF);
  4016 
  4017 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4018 "mutual_induct" no longer exists - the induction rule is always
  4019 contained in "induct";
  4020 
  4021 
  4022 * HOL/datatype package re-implemented and greatly improved: now
  4023 supports mutually recursive datatypes such as
  4024 
  4025   datatype
  4026     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4027             | SUM ('a aexp) ('a aexp)
  4028             | DIFF ('a aexp) ('a aexp)
  4029             | NUM 'a
  4030   and
  4031     'a bexp = LESS ('a aexp) ('a aexp)
  4032             | AND ('a bexp) ('a bexp)
  4033             | OR ('a bexp) ('a bexp)
  4034 
  4035 as well as indirectly recursive datatypes such as
  4036 
  4037   datatype
  4038     ('a, 'b) term = Var 'a
  4039                   | App 'b ((('a, 'b) term) list)
  4040 
  4041 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4042 induction on mutually / indirectly recursive datatypes.
  4043 
  4044 Primrec equations are now stored in theory and can be accessed via
  4045 <function_name>.simps.
  4046 
  4047 INCOMPATIBILITIES:
  4048 
  4049   - Theories using datatypes must now have theory Datatype as an
  4050     ancestor.
  4051   - The specific <typename>.induct_tac no longer exists - use the
  4052     generic induct_tac instead.
  4053   - natE has been renamed to nat.exhaust - use exhaust_tac
  4054     instead of res_inst_tac ... natE. Note that the variable
  4055     names in nat.exhaust differ from the names in natE, this
  4056     may cause some "fragile" proofs to fail.
  4057   - The theorems split_<typename>_case and split_<typename>_case_asm
  4058     have been renamed to <typename>.split and <typename>.split_asm.
  4059   - Since default sorts of type variables are now handled correctly,
  4060     some datatype definitions may have to be annotated with explicit
  4061     sort constraints.
  4062   - Primrec definitions no longer require function name and type
  4063     of recursive argument.
  4064 
  4065 Consider using isatool fixdatatype to adapt your theories and proof
  4066 scripts to the new package (backup your sources first!).
  4067 
  4068 
  4069 * HOL/record package: considerably improved implementation; now
  4070 includes concrete syntax for record types, terms, updates; theorems
  4071 for surjective pairing and splitting !!-bound record variables; proof
  4072 support is as follows:
  4073 
  4074   1) standard conversions (selectors or updates applied to record
  4075 constructor terms) are part of the standard simpset;
  4076 
  4077   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4078 made part of standard simpset and claset via addIffs;
  4079 
  4080   3) a tactic for record field splitting (record_split_tac) is part of
  4081 the standard claset (addSWrapper);
  4082 
  4083 To get a better idea about these rules you may retrieve them via
  4084 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4085 the name of your record type.
  4086 
  4087 The split tactic 3) conceptually simplifies by the following rule:
  4088 
  4089   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4090 
  4091 Thus any record variable that is bound by meta-all will automatically
  4092 blow up into some record constructor term, consequently the
  4093 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4094 solve record problems automatically.
  4095 
  4096 
  4097 * reorganized the main HOL image: HOL/Integ and String loaded by
  4098 default; theory Main includes everything;
  4099 
  4100 * automatic simplification of integer sums and comparisons, using cancellation;
  4101 
  4102 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4103 
  4104 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4105 
  4106 * many new identities for unions, intersections, set difference, etc.;
  4107 
  4108 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4109 called split_if, split_split, split_sum_case and split_nat_case (to go
  4110 with add/delsplits);
  4111 
  4112 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4113 (?x::unit) = (); this is made part of the default simpset, which COULD
  4114 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4115 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4116 unit_abs_eta_conv is added in order to counter the effect of
  4117 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4118 %u.f();
  4119 
  4120 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4121 makes more sense);
  4122 
  4123 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4124   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4125   disjointness reasoning but breaking a few old proofs.
  4126 
  4127 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4128 to 'converse' from 'inverse' (for compatibility with ZF and some
  4129 literature);
  4130 
  4131 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4132 the well-founded relation;
  4133 
  4134 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4135     Compl A.  The "Compl" syntax remains available as input syntax for this
  4136     release ONLY.
  4137 
  4138 * HOL/Update: new theory of function updates:
  4139     f(a:=b) == %x. if x=a then b else f x
  4140 may also be iterated as in f(a:=b,c:=d,...);
  4141 
  4142 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4143 
  4144 * HOL/List:
  4145   - new function list_update written xs[i:=v] that updates the i-th
  4146     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4147   - new function `upt' written [i..j(] which generates the list
  4148     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4149     bound write [i..j], which is a shorthand for [i..j+1(].
  4150   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4151 
  4152 * HOL/Arith:
  4153   - removed 'pred' (predecessor) function;
  4154   - generalized some theorems about n-1;
  4155   - many new laws about "div" and "mod";
  4156   - new laws about greatest common divisors (see theory ex/Primes);
  4157 
  4158 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4159 instead of "inverse";
  4160 
  4161 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4162   of the multiset ordering;
  4163 
  4164 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4165   (not included by default);
  4166 
  4167 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4168 
  4169 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4170   programs, i.e. different program variables may have different types.
  4171 
  4172 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4173   [previously, this check worked only if the rewrite rule was unconditional]
  4174   Now rew can involve either definitions or equalities (either == or =).
  4175 
  4176 
  4177 *** ZF ***
  4178 
  4179 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4180   only the theorems proved on ZF.ML;
  4181 
  4182 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4183   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4184   disjointness reasoning but breaking a few old proofs.
  4185 
  4186 * ZF/Update: new theory of function updates
  4187     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4188   may also be iterated as in f(a:=b,c:=d,...);
  4189 
  4190 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4191 
  4192 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4193   [previously, this check worked only if the rewrite rule was unconditional]
  4194   Now rew can involve either definitions or equalities (either == or =).
  4195 
  4196 * case_tac provided for compatibility with HOL
  4197     (like the old excluded_middle_tac, but with subgoals swapped)
  4198 
  4199 
  4200 *** Internal programming interfaces ***
  4201 
  4202 * Pure: several new basic modules made available for general use, see
  4203 also src/Pure/README;
  4204 
  4205 * improved the theory data mechanism to support encapsulation (data
  4206 kind name replaced by private Object.kind, acting as authorization
  4207 key); new type-safe user interface via functor TheoryDataFun; generic
  4208 print_data function becomes basically useless;
  4209 
  4210 * removed global_names compatibility flag -- all theory declarations
  4211 are qualified by default;
  4212 
  4213 * module Pure/Syntax now offers quote / antiquote translation
  4214 functions (useful for Hoare logic etc. with implicit dependencies);
  4215 see HOL/ex/Antiquote for an example use;
  4216 
  4217 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4218 cterm -> thm;
  4219 
  4220 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4221 subgoal;
  4222 
  4223 * Display.print_goals function moved to Locale.print_goals;
  4224 
  4225 * standard print function for goals supports current_goals_markers
  4226 variable for marking begin of proof, end of proof, start of goal; the
  4227 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4228 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4229 for example;
  4230 
  4231 
  4232 
  4233 New in Isabelle98 (January 1998)
  4234 --------------------------------
  4235 
  4236 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4237 
  4238 * changed lexical syntax of terms / types: dots made part of long
  4239 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4240 
  4241 * simpset (and claset) reference variable replaced by functions
  4242 simpset / simpset_ref;
  4243 
  4244 * no longer supports theory aliases (via merge) and non-trivial
  4245 implicit merge of thms' signatures;
  4246 
  4247 * most internal names of constants changed due to qualified names;
  4248 
  4249 * changed Pure/Sequence interface (see Pure/seq.ML);
  4250 
  4251 
  4252 *** General Changes ***
  4253 
  4254 * hierachically structured name spaces (for consts, types, axms, thms
  4255 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4256 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4257 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4258 long_names for fully qualified output names; NOTE: ML programs
  4259 (special tactics, packages etc.) referring to internal names may have
  4260 to be adapted to cope with fully qualified names; in case of severe
  4261 backward campatibility problems try setting 'global_names' at compile
  4262 time to have enrything declared within a flat name space; one may also
  4263 fine tune name declarations in theories via the 'global' and 'local'
  4264 section;
  4265 
  4266 * reimplemented the implicit simpset and claset using the new anytype
  4267 data filed in signatures; references simpset:simpset ref etc. are
  4268 replaced by functions simpset:unit->simpset and
  4269 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4270 to patch your ML files accordingly;
  4271 
  4272 * HTML output now includes theory graph data for display with Java
  4273 applet or isatool browser; data generated automatically via isatool
  4274 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4275 
  4276 * defs may now be conditional; improved rewrite_goals_tac to handle
  4277 conditional equations;
  4278 
  4279 * defs now admits additional type arguments, using TYPE('a) syntax;
  4280 
  4281 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4282 creates a new theory node; implicit merge of thms' signatures is
  4283 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4284 transfer:theory->thm->thm in (rare) cases;
  4285 
  4286 * improved handling of draft signatures / theories; draft thms (and
  4287 ctyps, cterms) are automatically promoted to real ones;
  4288 
  4289 * slightly changed interfaces for oracles: admit many per theory, named
  4290 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4291 
  4292 * print_goals: optional output of const types (set show_consts and
  4293 show_types);
  4294 
  4295 * improved output of warnings (###) and errors (***);
  4296 
  4297 * subgoal_tac displays a warning if the new subgoal has type variables;
  4298 
  4299 * removed old README and Makefiles;
  4300 
  4301 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4302 
  4303 * removed obsolete init_pps and init_database;
  4304 
  4305 * deleted the obsolete tactical STATE, which was declared by
  4306     fun STATE tacfun st = tacfun st st;
  4307 
  4308 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4309 (which abbreviates $HOME);
  4310 
  4311 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4312 use isatool fixseq to adapt your ML programs (this works for fully
  4313 qualified references to the Sequence structure only!);
  4314 
  4315 * use_thy no longer requires writable current directory; it always
  4316 reloads .ML *and* .thy file, if either one is out of date;
  4317 
  4318 
  4319 *** Classical Reasoner ***
  4320 
  4321 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4322 tactics that use classical reasoning to simplify a subgoal without
  4323 splitting it into several subgoals;
  4324 
  4325 * Safe_tac: like safe_tac but uses the default claset;
  4326 
  4327 
  4328 *** Simplifier ***
  4329 
  4330 * added simplification meta rules:
  4331     (asm_)(full_)simplify: simpset -> thm -> thm;
  4332 
  4333 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4334 logics (again);
  4335 
  4336 * added prems argument to simplification procedures;
  4337 
  4338 * HOL, FOL, ZF: added infix function `addsplits':
  4339   instead of `<simpset> setloop (split_tac <thms>)'
  4340   you can simply write `<simpset> addsplits <thms>'
  4341 
  4342 
  4343 *** Syntax ***
  4344 
  4345 * TYPE('a) syntax for type reflection terms;
  4346 
  4347 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4348 
  4349 * pretty printer: changed order of mixfix annotation preference (again!);
  4350 
  4351 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4352 
  4353 
  4354 *** HOL ***
  4355 
  4356 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4357   with `addloop' of the simplifier to faciliate case splitting in premises.
  4358 
  4359 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4360 
  4361 * HOL/Auth: new protocol proofs including some for the Internet
  4362   protocol TLS;
  4363 
  4364 * HOL/Map: new theory of `maps' a la VDM;
  4365 
  4366 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4367 cancelling out common nat summands from =, <, <= (in)equalities, or
  4368 differences; simplification procedures nat_cancel_factor for
  4369 cancelling common factor from =, <, <= (in)equalities over natural
  4370 sums; nat_cancel contains both kinds of procedures, it is installed by
  4371 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4372 
  4373 * HOL/simplifier: terms of the form
  4374   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4375   are rewritten to
  4376   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4377   and those of the form
  4378   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4379   are rewritten to
  4380   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4381 
  4382 * HOL/datatype
  4383   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4384 
  4385   P(t_case f1 ... fn x) =
  4386      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4387         ...
  4388        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4389      )
  4390 
  4391   and a theorem `split_t_case_asm' of the form
  4392 
  4393   P(t_case f1 ... fn x) =
  4394     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4395         ...
  4396        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4397      )
  4398   which can be added to a simpset via `addsplits'. The existing theorems
  4399   expand_list_case and expand_option_case have been renamed to
  4400   split_list_case and split_option_case.
  4401 
  4402 * HOL/Arithmetic:
  4403   - `pred n' is automatically converted to `n-1'.
  4404     Users are strongly encouraged not to use `pred' any longer,
  4405     because it will disappear altogether at some point.
  4406   - Users are strongly encouraged to write "0 < n" rather than
  4407     "n ~= 0". Theorems and proof tools have been modified towards this
  4408     `standard'.
  4409 
  4410 * HOL/Lists:
  4411   the function "set_of_list" has been renamed "set" (and its theorems too);
  4412   the function "nth" now takes its arguments in the reverse order and
  4413   has acquired the infix notation "!" as in "xs!n".
  4414 
  4415 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4416 
  4417 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4418   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4419 
  4420 * HOL/record: extensible records with schematic structural subtyping
  4421 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4422 still lacks various theorems and concrete record syntax;
  4423 
  4424 
  4425 *** HOLCF ***
  4426 
  4427 * removed "axioms" and "generated by" sections;
  4428 
  4429 * replaced "ops" section by extended "consts" section, which is capable of
  4430   handling the continuous function space "->" directly;
  4431 
  4432 * domain package:
  4433   . proves theorems immediately and stores them in the theory,
  4434   . creates hierachical name space,
  4435   . now uses normal mixfix annotations (instead of cinfix...),
  4436   . minor changes to some names and values (for consistency),
  4437   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4438   . separator between mutual domain defs: changed "," to "and",
  4439   . improved handling of sort constraints;  now they have to
  4440     appear on the left-hand side of the equations only;
  4441 
  4442 * fixed LAM <x,y,zs>.b syntax;
  4443 
  4444 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4445 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4446 
  4447 
  4448 *** FOL and ZF ***
  4449 
  4450 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4451   with `addloop' of the simplifier to faciliate case splitting in premises.
  4452 
  4453 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4454 in HOL, they strip ALL and --> from proved theorems;
  4455 
  4456 
  4457 
  4458 New in Isabelle94-8 (May 1997)
  4459 ------------------------------
  4460 
  4461 *** General Changes ***
  4462 
  4463 * new utilities to build / run / maintain Isabelle etc. (in parts
  4464 still somewhat experimental); old Makefiles etc. still functional;
  4465 
  4466 * new 'Isabelle System Manual';
  4467 
  4468 * INSTALL text, together with ./configure and ./build scripts;
  4469 
  4470 * reimplemented type inference for greater efficiency, better error
  4471 messages and clean internal interface;
  4472 
  4473 * prlim command for dealing with lots of subgoals (an easier way of
  4474 setting goals_limit);
  4475 
  4476 
  4477 *** Syntax ***
  4478 
  4479 * supports alternative (named) syntax tables (parser and pretty
  4480 printer); internal interface is provided by add_modesyntax(_i);
  4481 
  4482 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4483 be used in conjunction with the Isabelle symbol font; uses the
  4484 "symbols" syntax table;
  4485 
  4486 * added token_translation interface (may translate name tokens in
  4487 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4488 the current print_mode); IMPORTANT: user print translation functions
  4489 are responsible for marking newly introduced bounds
  4490 (Syntax.mark_boundT);
  4491 
  4492 * token translations for modes "xterm" and "xterm_color" that display
  4493 names in bold, underline etc. or colors (which requires a color
  4494 version of xterm);
  4495 
  4496 * infixes may now be declared with names independent of their syntax;
  4497 
  4498 * added typed_print_translation (like print_translation, but may
  4499 access type of constant);
  4500 
  4501 
  4502 *** Classical Reasoner ***
  4503 
  4504 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4505 some limitations.  Blast_tac...
  4506   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4507   + ignores elimination rules that don't have the correct format
  4508         (the conclusion MUST be a formula variable)
  4509   + ignores types, which can make HOL proofs fail
  4510   + rules must not require higher-order unification, e.g. apply_type in ZF
  4511     [message "Function Var's argument not a bound variable" relates to this]
  4512   + its proof strategy is more general but can actually be slower
  4513 
  4514 * substitution with equality assumptions no longer permutes other
  4515 assumptions;
  4516 
  4517 * minor changes in semantics of addafter (now called addaltern); renamed
  4518 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4519 (and access functions for it);
  4520 
  4521 * improved combination of classical reasoner and simplifier:
  4522   + functions for handling clasimpsets
  4523   + improvement of addss: now the simplifier is called _after_ the
  4524     safe steps.
  4525   + safe variant of addss called addSss: uses safe simplifications
  4526     _during_ the safe steps. It is more complete as it allows multiple
  4527     instantiations of unknowns (e.g. with slow_tac).
  4528 
  4529 *** Simplifier ***
  4530 
  4531 * added interface for simplification procedures (functions that
  4532 produce *proven* rewrite rules on the fly, depending on current
  4533 redex);
  4534 
  4535 * ordering on terms as parameter (used for ordered rewriting);
  4536 
  4537 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4538 
  4539 * the solver is now split into a safe and an unsafe part.
  4540 This should be invisible for the normal user, except that the
  4541 functions setsolver and addsolver have been renamed to setSolver and
  4542 addSolver; added safe_asm_full_simp_tac;
  4543 
  4544 
  4545 *** HOL ***
  4546 
  4547 * a generic induction tactic `induct_tac' which works for all datatypes and
  4548 also for type `nat';
  4549 
  4550 * a generic case distinction tactic `exhaust_tac' which works for all
  4551 datatypes and also for type `nat';
  4552 
  4553 * each datatype comes with a function `size';
  4554 
  4555 * patterns in case expressions allow tuple patterns as arguments to
  4556 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4557 
  4558 * primrec now also works with type nat;
  4559 
  4560 * recdef: a new declaration form, allows general recursive functions to be
  4561 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4562 
  4563 * the constant for negation has been renamed from "not" to "Not" to
  4564 harmonize with FOL, ZF, LK, etc.;
  4565 
  4566 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4567 infinite lists;
  4568 
  4569 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4570 
  4571 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4572 problems in commutative rings, using axiomatic type classes for + and *;
  4573 
  4574 * more examples in HOL/MiniML and HOL/Auth;
  4575 
  4576 * more default rewrite rules for quantifiers, union/intersection;
  4577 
  4578 * a new constant `arbitrary == @x.False';
  4579 
  4580 * HOLCF/IOA replaces old HOL/IOA;
  4581 
  4582 * HOLCF changes: derived all rules and arities
  4583   + axiomatic type classes instead of classes
  4584   + typedef instead of faking type definitions
  4585   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4586   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4587   + eliminated the types void, one, tr
  4588   + use unit lift and bool lift (with translations) instead of one and tr
  4589   + eliminated blift from Lift3.thy (use Def instead of blift)
  4590   all eliminated rules are derived as theorems --> no visible changes ;
  4591 
  4592 
  4593 *** ZF ***
  4594 
  4595 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4596 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4597 as ZF_cs addSIs [equalityI];
  4598 
  4599 
  4600 
  4601 New in Isabelle94-7 (November 96)
  4602 ---------------------------------
  4603 
  4604 * allowing negative levels (as offsets) in prlev and choplev;
  4605 
  4606 * super-linear speedup for large simplifications;
  4607 
  4608 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4609 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4610 FAIL); can suppress it using the command Delsimps (ex_simps @
  4611 all_simps); De Morgan laws are also now included, by default;
  4612 
  4613 * improved printing of ==>  :  ~:
  4614 
  4615 * new object-logic "Sequents" adds linear logic, while replacing LK
  4616 and Modal (thanks to Sara Kalvala);
  4617 
  4618 * HOL/Auth: correctness proofs for authentication protocols;
  4619 
  4620 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4621 examples on HOL/Auth);
  4622 
  4623 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4624 the rewriter and classical reasoner simultaneously;
  4625 
  4626 * function uresult no longer returns theorems in "standard" format;
  4627 regain previous version by: val uresult = standard o uresult;
  4628 
  4629 
  4630 
  4631 New in Isabelle94-6
  4632 -------------------
  4633 
  4634 * oracles -- these establish an interface between Isabelle and trusted
  4635 external reasoners, which may deliver results as theorems;
  4636 
  4637 * proof objects (in particular record all uses of oracles);
  4638 
  4639 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4640 
  4641 * "constdefs" section in theory files;
  4642 
  4643 * "primrec" section (HOL) no longer requires names;
  4644 
  4645 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4646 
  4647 
  4648 
  4649 New in Isabelle94-5
  4650 -------------------
  4651 
  4652 * reduced space requirements;
  4653 
  4654 * automatic HTML generation from theories;
  4655 
  4656 * theory files no longer require "..." (quotes) around most types;
  4657 
  4658 * new examples, including two proofs of the Church-Rosser theorem;
  4659 
  4660 * non-curried (1994) version of HOL is no longer distributed;
  4661 
  4662 
  4663 
  4664 New in Isabelle94-4
  4665 -------------------
  4666 
  4667 * greatly reduced space requirements;
  4668 
  4669 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4670 
  4671 * searchable theorem database (see the section "Retrieving theorems" on
  4672 page 8 of the Reference Manual);
  4673 
  4674 * new examples, including Grabczewski's monumental case study of the
  4675 Axiom of Choice;
  4676 
  4677 * The previous version of HOL renamed to Old_HOL;
  4678 
  4679 * The new version of HOL (previously called CHOL) uses a curried syntax
  4680 for functions.  Application looks like f a b instead of f(a,b);
  4681 
  4682 * Mutually recursive inductive definitions finally work in HOL;
  4683 
  4684 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4685 translates to the operator "split";
  4686 
  4687 
  4688 
  4689 New in Isabelle94-3
  4690 -------------------
  4691 
  4692 * new infix operator, addss, allowing the classical reasoner to
  4693 perform simplification at each step of its search.  Example:
  4694         fast_tac (cs addss ss)
  4695 
  4696 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4697 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4698 look like (a,b) instead of <a,b>;
  4699 
  4700 * PLEASE NOTE: CHOL will eventually replace HOL!
  4701 
  4702 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4703 It translates to the operator "split".  A new theory of integers is available;
  4704 
  4705 * In ZF, integer numerals now denote two's-complement binary integers.
  4706 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4707 
  4708 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4709 of the Axiom of Choice;
  4710 
  4711 
  4712 
  4713 New in Isabelle94-2
  4714 -------------------
  4715 
  4716 * Significantly faster resolution;
  4717 
  4718 * the different sections in a .thy file can now be mixed and repeated
  4719 freely;
  4720 
  4721 * Database of theorems for FOL, HOL and ZF.  New
  4722 commands including qed, qed_goal and bind_thm store theorems in the database.
  4723 
  4724 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4725 a given theory (thms_of), or find out what theory a theorem was proved in
  4726 (theory_of_thm);
  4727 
  4728 * Bugs fixed in the inductive definition and datatype packages;
  4729 
  4730 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4731 and HOL_dup_cs obsolete;
  4732 
  4733 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4734 have been removed;
  4735 
  4736 * Simpler definition of function space in ZF;
  4737 
  4738 * new results about cardinal and ordinal arithmetic in ZF;
  4739 
  4740 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4741 types;
  4742 
  4743 
  4744 $Id$