NEWS
author huffman
Mon May 14 19:14:50 2007 +0200 (2007-05-14)
changeset 22971 a6812b6a36a5
parent 22965 b81bbe298406
child 22972 3e96b98d37c6
permissions -rw-r--r--
root and sqrt on negative inputs
     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 
   904 * Complex: Some complex-specific constants are now abbreviations for
   905 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   906 hnorm.  Other constants have been entirely removed in favor of the
   907 polymorphic versions (INCOMPATIBILITY):
   908 
   909   approx        <-- capprox
   910   HFinite       <-- CFinite
   911   HInfinite     <-- CInfinite
   912   Infinitesimal <-- CInfinitesimal
   913   monad         <-- cmonad
   914   galaxy        <-- cgalaxy
   915   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   916   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   917   (ns)deriv     <-- (ns)cderiv
   918 
   919 
   920 *** ML ***
   921 
   922 * Context data interfaces (Theory/Proof/GenericDataFun): removed
   923 name/print, uninitialized data defaults to ad-hoc copy of empty value,
   924 init only required for impure data.  INCOMPATIBILITY: empty really
   925 need to be empty (no dependencies on theory content!)
   926 
   927 * ML within Isar: antiquotations allow to embed statically-checked
   928 formal entities in the source, referring to the context available at
   929 compile-time.  For example:
   930 
   931 ML {* @{typ "'a => 'b"} *}
   932 ML {* @{term "%x. x"} *}
   933 ML {* @{prop "x == y"} *}
   934 ML {* @{ctyp "'a => 'b"} *}
   935 ML {* @{cterm "%x. x"} *}
   936 ML {* @{cprop "x == y"} *}
   937 ML {* @{thm asm_rl} *}
   938 ML {* @{thms asm_rl} *}
   939 ML {* @{const_name c} *}
   940 ML {* @{const_syntax c} *}
   941 ML {* @{context} *}
   942 ML {* @{theory} *}
   943 ML {* @{theory Pure} *}
   944 ML {* @{simpset} *}
   945 ML {* @{claset} *}
   946 ML {* @{clasimpset} *}
   947 
   948 The same works for sources being ``used'' within an Isar context.
   949 
   950 * ML in Isar: improved error reporting; extra verbosity with
   951 Toplevel.debug enabled.
   952 
   953 * Pure/library:
   954 
   955   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   956   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   957 
   958 The semantics of "burrow" is: "take a function with *simulatanously*
   959 transforms a list of value, and apply it *simulatanously* to a list of
   960 list of values of the appropriate type". Compare this with "map" which
   961 would *not* apply its argument function simulatanously but in
   962 sequence; "fold_burrow" has an additional context.
   963 
   964 * Pure/library: functions map2 and fold2 with curried syntax for
   965 simultanous mapping and folding:
   966 
   967     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   968     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   969 
   970 * Pure/library: indexed lists - some functions in the Isabelle library
   971 treating lists over 'a as finite mappings from [0...n] to 'a have been
   972 given more convenient names and signatures reminiscent of similar
   973 functions for alists, tables, etc:
   974 
   975   val nth: 'a list -> int -> 'a 
   976   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   977   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   978 
   979 Note that fold_index starts counting at index 0, not 1 like foldln
   980 used to.
   981 
   982 * Pure/library: added general ``divide_and_conquer'' combinator on
   983 lists.
   984 
   985 * Pure/General/table.ML: the join operations now works via exceptions
   986 DUP/SAME instead of type option.  This is simpler in simple cases, and
   987 admits slightly more efficient complex applications.
   988 
   989 * Pure: datatype Context.generic joins theory/Proof.context and
   990 provides some facilities for code that works in either kind of
   991 context, notably GenericDataFun for uniform theory and proof data.
   992 
   993 * Pure: 'advanced' translation functions (parse_translation etc.) now
   994 use Context.generic instead of just theory.
   995 
   996 * Pure: simplified internal attribute type, which is now always
   997 Context.generic * thm -> Context.generic * thm.  Global (theory)
   998 vs. local (Proof.context) attributes have been discontinued, while
   999 minimizing code duplication.  Thm.rule_attribute and
  1000 Thm.declaration_attribute build canonical attributes; see also
  1001 structure Context for further operations on Context.generic, notably
  1002 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1003 declarations and definitions.
  1004 
  1005 * Pure/kernel: consts certification ignores sort constraints given in
  1006 signature declarations.  (This information is not relevant to the
  1007 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1008 potential INCOMPATIBILITY.
  1009 
  1010 * Pure: axiomatic type classes are now purely definitional, with
  1011 explicit proofs of class axioms and super class relations performed
  1012 internally.  See Pure/axclass.ML for the main internal interfaces --
  1013 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1014 AxClass.axiomatize_class/classrel/arity supercede
  1015 Sign.add_classes/classrel/arities.
  1016 
  1017 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1018 global/local versions on theory vs. Proof.context have been
  1019 discontinued; Attrib.syntax and Method.syntax have been adapted
  1020 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1021 attributes, methods, etc.
  1022 
  1023 * Pure: several functions of signature "... -> theory -> theory * ..."
  1024 have been reoriented to "... -> theory -> ... * theory" in order to
  1025 allow natural usage in combination with the ||>, ||>>, |-> and
  1026 fold_map combinators.
  1027 
  1028 * Pure: official theorem names (closed derivations) and additional
  1029 comments (tags) are now strictly separate.  Name hints -- which are
  1030 maintained as tags -- may be attached any time without affecting the
  1031 derivation.
  1032 
  1033 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1034 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1035 achieve the old behaviour.
  1036 
  1037 * Pure: the "Goal" constant is now called "prop", supporting a
  1038 slightly more general idea of ``protecting'' meta-level rule
  1039 statements.
  1040 
  1041 * Pure: Logic.(un)varify only works in a global context, which is now
  1042 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1043 Logic.legacy_(un)varify as temporary workaround.
  1044 
  1045 * Pure: structure Name provides scalable operations for generating
  1046 internal variable names, notably Name.variants etc.  This replaces
  1047 some popular functions from term.ML:
  1048 
  1049   Term.variant		->  Name.variant
  1050   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1051   Term.invent_names	->  Name.invent_list
  1052 
  1053 Note that low-level renaming rarely occurs in new code -- operations
  1054 from structure Variable are used instead (see below).
  1055 
  1056 * Pure: structure Variable provides fundamental operations for proper
  1057 treatment of fixed/schematic variables in a context.  For example,
  1058 Variable.import introduces fixes for schematics of given facts and
  1059 Variable.export reverses the effect (up to renaming) -- this replaces
  1060 various freeze_thaw operations.
  1061 
  1062 * Pure: structure Goal provides simple interfaces for
  1063 init/conclude/finish and tactical prove operations (replacing former
  1064 Tactic.prove).  Goal.prove is the canonical way to prove results
  1065 within a given context; Goal.prove_global is a degraded version for
  1066 theory level goals, including a global Drule.standard.  Note that
  1067 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1068 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1069 in a locale context).
  1070 
  1071 * Isar: simplified treatment of user-level errors, using exception
  1072 ERROR of string uniformly.  Function error now merely raises ERROR,
  1073 without any side effect on output channels.  The Isar toplevel takes
  1074 care of proper display of ERROR exceptions.  ML code may use plain
  1075 handle/can/try; cat_error may be used to concatenate errors like this:
  1076 
  1077   ... handle ERROR msg => cat_error msg "..."
  1078 
  1079 Toplevel ML code (run directly or through the Isar toplevel) may be
  1080 embedded into the Isar toplevel with exception display/debug like
  1081 this:
  1082 
  1083   Isar.toplevel (fn () => ...)
  1084 
  1085 INCOMPATIBILITY, removed special transform_error facilities, removed
  1086 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1087 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1088 -- use plain ERROR instead.
  1089 
  1090 * Isar: theory setup now has type (theory -> theory), instead of a
  1091 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1092 
  1093 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1094 subject to ProofContext.debug/verbose flags.
  1095 
  1096 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1097 theory before entering a proof state.  Transactions now always see a
  1098 quasi-functional intermediate checkpoint, both in interactive and
  1099 batch mode.
  1100 
  1101 * Simplifier: the simpset of a running simplification process now
  1102 contains a proof context (cf. Simplifier.the_context), which is the
  1103 very context that the initial simpset has been retrieved from (by
  1104 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1105 (solver, looper etc.) may depend on arbitrary proof data.
  1106 
  1107 * Simplifier.inherit_context inherits the proof context (plus the
  1108 local bounds) of the current simplification process; any simproc
  1109 etc. that calls the Simplifier recursively should do this!  Removed
  1110 former Simplifier.inherit_bounds, which is already included here --
  1111 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1112 specify an explicit context using Simplifier.context/theory_context.
  1113 
  1114 * Simplifier/Classical Reasoner: more abstract interfaces
  1115 change_simpset/claset for modifying the simpset/claset reference of a
  1116 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1117 INCOMPATIBILITY.
  1118 
  1119 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1120 "Trueprop" etc.
  1121 
  1122 
  1123 *** System ***
  1124 
  1125 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1126 locations -- now includes the Isabelle version identifier as well.
  1127 This simplifies use of multiple Isabelle installations.
  1128 
  1129 * isabelle-process: option -S (secure mode) disables some critical
  1130 operations, notably runtime compilation and evaluation of ML source
  1131 code.
  1132 
  1133 
  1134 New in Isabelle2005 (October 2005)
  1135 ----------------------------------
  1136 
  1137 *** General ***
  1138 
  1139 * Theory headers: the new header syntax for Isar theories is
  1140 
  1141   theory <name>
  1142   imports <theory1> ... <theoryN>
  1143   uses <file1> ... <fileM>
  1144   begin
  1145 
  1146 where the 'uses' part is optional.  The previous syntax
  1147 
  1148   theory <name> = <theory1> + ... + <theoryN>:
  1149 
  1150 will disappear in the next release.  Use isatool fixheaders to convert
  1151 existing theory files.  Note that there is no change in ancient
  1152 non-Isar theories now, but these will disappear soon.
  1153 
  1154 * Theory loader: parent theories can now also be referred to via
  1155 relative and absolute paths.
  1156 
  1157 * Command 'find_theorems' searches for a list of criteria instead of a
  1158 list of constants. Known criteria are: intro, elim, dest, name:string,
  1159 simp:term, and any term. Criteria can be preceded by '-' to select
  1160 theorems that do not match. Intro, elim, dest select theorems that
  1161 match the current goal, name:s selects theorems whose fully qualified
  1162 name contain s, and simp:term selects all simplification rules whose
  1163 lhs match term.  Any other term is interpreted as pattern and selects
  1164 all theorems matching the pattern. Available in ProofGeneral under
  1165 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1166 
  1167   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1168 
  1169 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1170 matching the current goal as introduction rule and not having "HOL."
  1171 in their name (i.e. not being defined in theory HOL).
  1172 
  1173 * Command 'thms_containing' has been discontinued in favour of
  1174 'find_theorems'; INCOMPATIBILITY.
  1175 
  1176 * Communication with Proof General is now 8bit clean, which means that
  1177 Unicode text in UTF-8 encoding may be used within theory texts (both
  1178 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1179 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1180 
  1181   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1182   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1183 
  1184 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1185 Classical Reasoner.  Typical big applications run around 2 times
  1186 faster.
  1187 
  1188 
  1189 *** Document preparation ***
  1190 
  1191 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1192 of raw sources.  Only those symbols that do not require additional
  1193 LaTeX packages (depending on comments in isabellesym.sty) are
  1194 displayed properly, everything else is left verbatim.  isatool display
  1195 and isatool print are used as front ends (these are subject to the
  1196 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1197 
  1198 * Command tags control specific markup of certain regions of text,
  1199 notably folding and hiding.  Predefined tags include "theory" (for
  1200 theory begin and end), "proof" for proof commands, and "ML" for
  1201 commands involving ML code; the additional tags "visible" and
  1202 "invisible" are unused by default.  Users may give explicit tag
  1203 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1204 interpretation of tags is determined by the LaTeX job during document
  1205 preparation: see option -V of isatool usedir, or options -n and -t of
  1206 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1207 \isadroptag.
  1208 
  1209 Several document versions may be produced at the same time via isatool
  1210 usedir (the generated index.html will link all of them).  Typical
  1211 specifications include ''-V document=theory,proof,ML'' to present
  1212 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1213 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1214 these parts without any formal replacement text.  The Isabelle site
  1215 default settings produce ''document'' and ''outline'' versions as
  1216 specified above.
  1217 
  1218 * Several new antiquotations:
  1219 
  1220   @{term_type term} prints a term with its type annotated;
  1221 
  1222   @{typeof term} prints the type of a term;
  1223 
  1224   @{const const} is the same as @{term const}, but checks that the
  1225   argument is a known logical constant;
  1226 
  1227   @{term_style style term} and @{thm_style style thm} print a term or
  1228   theorem applying a "style" to it
  1229 
  1230   @{ML text}
  1231 
  1232 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1233 definitions, equations, inequations etc., 'concl' printing only the
  1234 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1235 to print the specified premise.  TermStyle.add_style provides an ML
  1236 interface for introducing further styles.  See also the "LaTeX Sugar"
  1237 document practical applications.  The ML antiquotation prints
  1238 type-checked ML expressions verbatim.
  1239 
  1240 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1241 and 'text' support optional locale specification '(in loc)', which
  1242 specifies the default context for interpreting antiquotations.  For
  1243 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1244 
  1245 * Option 'locale=NAME' of antiquotations specifies an alternative
  1246 context interpreting the subsequent argument.  For example: @{thm
  1247 [locale=lattice] inf_assoc}.
  1248 
  1249 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1250 a proof context.
  1251 
  1252 * Proper output of antiquotations for theory commands involving a
  1253 proof context (such as 'locale' or 'theorem (in loc) ...').
  1254 
  1255 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1256 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1257 
  1258 * isatool usedir: new option -C (default true) controls whether option
  1259 -D should include a copy of the original document directory; -C false
  1260 prevents unwanted effects such as copying of administrative CVS data.
  1261 
  1262 
  1263 *** Pure ***
  1264 
  1265 * Considerably improved version of 'constdefs' command.  Now performs
  1266 automatic type-inference of declared constants; additional support for
  1267 local structure declarations (cf. locales and HOL records), see also
  1268 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1269 sequential dependencies of definitions within a single 'constdefs'
  1270 section; moreover, the declared name needs to be an identifier.  If
  1271 all fails, consider to fall back on 'consts' and 'defs' separately.
  1272 
  1273 * Improved indexed syntax and implicit structures.  First of all,
  1274 indexed syntax provides a notational device for subscripted
  1275 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1276 expressions.  Secondly, in a local context with structure
  1277 declarations, number indexes \<^sub>n or the empty index (default
  1278 number 1) refer to a certain fixed variable implicitly; option
  1279 show_structs controls printing of implicit structures.  Typical
  1280 applications of these concepts involve record types and locales.
  1281 
  1282 * New command 'no_syntax' removes grammar declarations (and
  1283 translations) resulting from the given syntax specification, which is
  1284 interpreted in the same manner as for the 'syntax' command.
  1285 
  1286 * 'Advanced' translation functions (parse_translation etc.) may depend
  1287 on the signature of the theory context being presently used for
  1288 parsing/printing, see also isar-ref manual.
  1289 
  1290 * Improved 'oracle' command provides a type-safe interface to turn an
  1291 ML expression of type theory -> T -> term into a primitive rule of
  1292 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1293 is already included here); see also FOL/ex/IffExample.thy;
  1294 INCOMPATIBILITY.
  1295 
  1296 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1297 before); "cI" is no longer bound, use "c.intro" instead.
  1298 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1299 axclasses vs. locales.
  1300 
  1301 * Improved internal renaming of symbolic identifiers -- attach primes
  1302 instead of base 26 numbers.
  1303 
  1304 * New flag show_question_marks controls printing of leading question
  1305 marks in schematic variable names.
  1306 
  1307 * In schematic variable names, *any* symbol following \<^isub> or
  1308 \<^isup> is now treated as part of the base name.  For example, the
  1309 following works without printing of awkward ".0" indexes:
  1310 
  1311   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1312     by simp
  1313 
  1314 * Inner syntax includes (*(*nested*) comments*).
  1315 
  1316 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1317 annotations as "(00...)".
  1318 
  1319 * Clear separation of logical types and nonterminals, where the latter
  1320 may only occur in 'syntax' specifications or type abbreviations.
  1321 Before that distinction was only partially implemented via type class
  1322 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1323 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1324 exotic syntax specifications may require further adaption
  1325 (e.g. Cube/Cube.thy).
  1326 
  1327 * Removed obsolete type class "logic", use the top sort {} instead.
  1328 Note that non-logical types should be declared as 'nonterminals'
  1329 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1330 specifications.
  1331 
  1332 * Attributes 'induct' and 'cases': type or set names may now be
  1333 locally fixed variables as well.
  1334 
  1335 * Simplifier: can now control the depth to which conditional rewriting
  1336 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1337 Limit.
  1338 
  1339 * Simplifier: simplification procedures may now take the current
  1340 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1341 interface), which is very useful for calling the Simplifier
  1342 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1343 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1344 low-level mk_simproc no longer applies Logic.varify internally, to
  1345 allow for use in a context of fixed variables.
  1346 
  1347 * thin_tac now works even if the assumption being deleted contains !!
  1348 or ==>.  More generally, erule now works even if the major premise of
  1349 the elimination rule contains !! or ==>.
  1350 
  1351 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1352 
  1353 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1354 from Pure, which contains all common declarations already.  Both
  1355 theories are defined via plain Isabelle/Isar .thy files.
  1356 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1357 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1358 use isatool fixcpure to adapt your theory and ML sources.
  1359 
  1360 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1361 selections of theorems in named facts via index ranges.
  1362 
  1363 * 'print_theorems': in theory mode, really print the difference
  1364 wrt. the last state (works for interactive theory development only),
  1365 in proof mode print all local facts (cf. 'print_facts');
  1366 
  1367 * 'hide': option '(open)' hides only base names.
  1368 
  1369 * More efficient treatment of intermediate checkpoints in interactive
  1370 theory development.
  1371 
  1372 * Code generator is now invoked via code_module (incremental code
  1373 generation) and code_library (modular code generation, ML structures
  1374 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1375 must be quoted when used as identifiers.
  1376 
  1377 * New 'value' command for reading, evaluating and printing terms using
  1378 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1379 quoted when used as identifier.
  1380 
  1381 
  1382 *** Locales ***
  1383 
  1384 * New commands for the interpretation of locale expressions in
  1385 theories (1), locales (2) and proof contexts (3).  These generate
  1386 proof obligations from the expression specification.  After the
  1387 obligations have been discharged, theorems of the expression are added
  1388 to the theory, target locale or proof context.  The synopsis of the
  1389 commands is a follows:
  1390 
  1391   (1) interpretation expr inst
  1392   (2) interpretation target < expr
  1393   (3) interpret expr inst
  1394 
  1395 Interpretation in theories and proof contexts require a parameter
  1396 instantiation of terms from the current context.  This is applied to
  1397 specifications and theorems of the interpreted expression.
  1398 Interpretation in locales only permits parameter renaming through the
  1399 locale expression.  Interpretation is smart in that interpretations
  1400 that are active already do not occur in proof obligations, neither are
  1401 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1402 inspect active interpretations of a particular locale.  For details,
  1403 see the Isar Reference manual.  Examples can be found in
  1404 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1405 
  1406 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1407 'interpret' instead.
  1408 
  1409 * New context element 'constrains' for adding type constraints to
  1410 parameters.
  1411 
  1412 * Context expressions: renaming of parameters with syntax
  1413 redeclaration.
  1414 
  1415 * Locale declaration: 'includes' disallowed.
  1416 
  1417 * Proper static binding of attribute syntax -- i.e. types / terms /
  1418 facts mentioned as arguments are always those of the locale definition
  1419 context, independently of the context of later invocations.  Moreover,
  1420 locale operations (renaming and type / term instantiation) are applied
  1421 to attribute arguments as expected.
  1422 
  1423 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1424 actual attributes; rare situations may require Attrib.attribute to
  1425 embed those attributes into Attrib.src that lack concrete syntax.
  1426 Attribute implementations need to cooperate properly with the static
  1427 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1428 Attrib.XXX_thm etc. already do the right thing without further
  1429 intervention.  Only unusual applications -- such as "where" or "of"
  1430 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1431 on the context and the facts involved -- may have to assign parsed
  1432 values to argument tokens explicitly.
  1433 
  1434 * Changed parameter management in theorem generation for long goal
  1435 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1436 theorem statement in rare situations.
  1437 
  1438 * Locale inspection command 'print_locale' omits notes elements.  Use
  1439 'print_locale!' to have them included in the output.
  1440 
  1441 
  1442 *** Provers ***
  1443 
  1444 * Provers/hypsubst.ML: improved version of the subst method, for
  1445 single-step rewriting: it now works in bound variable contexts. New is
  1446 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1447 rewrite a different subterm than the original subst method, which is
  1448 still available as 'simplesubst'.
  1449 
  1450 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1451 and quasi orders.
  1452 
  1453 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1454 reflexive-transitive closure of relations.
  1455 
  1456 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1457 limit (previously hard-coded with a value of 20) user-definable.
  1458 
  1459 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1460 is peformed already.  Object-logics merely need to finish their
  1461 initial simpset configuration as before.  INCOMPATIBILITY.
  1462 
  1463 
  1464 *** HOL ***
  1465 
  1466 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1467 
  1468   syntax (epsilon)
  1469     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1470 
  1471 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1472 and x-symbol; use option '-m epsilon' to get it actually printed.
  1473 Moreover, the mathematically important symbolic identifier \<epsilon>
  1474 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1475 
  1476 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1477 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1478 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1479 support corresponding Isar calculations.
  1480 
  1481 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1482 instead of ":".
  1483 
  1484 * theory SetInterval: changed the syntax for open intervals:
  1485 
  1486   Old       New
  1487   {..n(}    {..<n}
  1488   {)n..}    {n<..}
  1489   {m..n(}   {m..<n}
  1490   {)m..n}   {m<..n}
  1491   {)m..n(}  {m<..<n}
  1492 
  1493 The old syntax is still supported but will disappear in the next
  1494 release.  For conversion use the following Emacs search and replace
  1495 patterns (these are not perfect but work quite well):
  1496 
  1497   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1498   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1499 
  1500 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1501 equalities in commutative rings; method 'algebra' provides a generic
  1502 interface.
  1503 
  1504 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1505 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1506 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1507 be a tuple pattern.
  1508 
  1509 Some new syntax forms are available:
  1510 
  1511   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1512   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1513   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1514   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1515 
  1516 The latter form "\<Sum>x < k. e" used to be based on a separate
  1517 function "Summation", which has been discontinued.
  1518 
  1519 * theory Finite_Set: in structured induction proofs, the insert case
  1520 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1521 (insert F x)'.
  1522 
  1523 * The 'refute' command has been extended to support a much larger
  1524 fragment of HOL, including axiomatic type classes, constdefs and
  1525 typedefs, inductive datatypes and recursion.
  1526 
  1527 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1528 Requires zChaff with proof generation to be installed.  See
  1529 HOL/ex/SAT_Examples.thy for examples.
  1530 
  1531 * Datatype induction via method 'induct' now preserves the name of the
  1532 induction variable. For example, when proving P(xs::'a list) by
  1533 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1534 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1535 in unstructured proof scripts.
  1536 
  1537 * Reworked implementation of records.  Improved scalability for
  1538 records with many fields, avoiding performance problems for type
  1539 inference. Records are no longer composed of nested field types, but
  1540 of nested extension types. Therefore the record type only grows linear
  1541 in the number of extensions and not in the number of fields.  The
  1542 top-level (users) view on records is preserved.  Potential
  1543 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1544 old record representation. The type generated for a record is called
  1545 <record_name>_ext_type.
  1546 
  1547 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1548 proofs triggered by a record definition or a simproc (if
  1549 quick_and_dirty is enabled).  Definitions of large records can take
  1550 quite long.
  1551 
  1552 New simproc record_upd_simproc for simplification of multiple record
  1553 updates enabled by default.  Moreover, trivial updates are also
  1554 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1555 occasionally, since simplification is more powerful by default.
  1556 
  1557 * typedef: proper support for polymorphic sets, which contain extra
  1558 type-variables in the term.
  1559 
  1560 * Simplifier: automatically reasons about transitivity chains
  1561 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1562 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1563 old proofs break occasionally as simplification may now solve more
  1564 goals than previously.
  1565 
  1566 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1567 present.  Works for all partial orders (class "order"), in particular
  1568 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1569 just like y <= x.
  1570 
  1571 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1572 bound variable or a constant then the let is unfolded.  Otherwise
  1573 first a is simplified to b, and then f b is simplified to g. If
  1574 possible we abstract b from g arriving at "let x = b in h x",
  1575 otherwise we unfold the let and arrive at g.  The simproc can be
  1576 enabled/disabled by the reference use_let_simproc.  Potential
  1577 INCOMPATIBILITY since simplification is more powerful by default.
  1578 
  1579 * Classical reasoning: the meson method now accepts theorems as arguments.
  1580 
  1581 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1582 jobs to provide advice on the provability of subgoals.
  1583 
  1584 * Theory OrderedGroup and Ring_and_Field: various additions and
  1585 improvements to faciliate calculations involving equalities and
  1586 inequalities.
  1587 
  1588 The following theorems have been eliminated or modified
  1589 (INCOMPATIBILITY):
  1590 
  1591   abs_eq             now named abs_of_nonneg
  1592   abs_of_ge_0        now named abs_of_nonneg
  1593   abs_minus_eq       now named abs_of_nonpos
  1594   imp_abs_id         now named abs_of_nonneg
  1595   imp_abs_neg_id     now named abs_of_nonpos
  1596   mult_pos           now named mult_pos_pos
  1597   mult_pos_le        now named mult_nonneg_nonneg
  1598   mult_pos_neg_le    now named mult_nonneg_nonpos
  1599   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1600   mult_neg           now named mult_neg_neg
  1601   mult_neg_le        now named mult_nonpos_nonpos
  1602 
  1603 * Theory Parity: added rules for simplifying exponents.
  1604 
  1605 * Theory List:
  1606 
  1607 The following theorems have been eliminated or modified
  1608 (INCOMPATIBILITY):
  1609 
  1610   list_all_Nil       now named list_all.simps(1)
  1611   list_all_Cons      now named list_all.simps(2)
  1612   list_all_conv      now named list_all_iff
  1613   set_mem_eq         now named mem_iff
  1614 
  1615 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1616 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1617 
  1618 
  1619 *** HOL-Complex ***
  1620 
  1621 * Theory RealDef: better support for embedding natural numbers and
  1622 integers in the reals.
  1623 
  1624 The following theorems have been eliminated or modified
  1625 (INCOMPATIBILITY):
  1626 
  1627   exp_ge_add_one_self  now requires no hypotheses
  1628   real_of_int_add      reversed direction of equality (use [symmetric])
  1629   real_of_int_minus    reversed direction of equality (use [symmetric])
  1630   real_of_int_diff     reversed direction of equality (use [symmetric])
  1631   real_of_int_mult     reversed direction of equality (use [symmetric])
  1632 
  1633 * Theory RComplete: expanded support for floor and ceiling functions.
  1634 
  1635 * Theory Ln is new, with properties of the natural logarithm
  1636 
  1637 * Hyperreal: There is a new type constructor "star" for making
  1638 nonstandard types.  The old type names are now type synonyms:
  1639 
  1640   hypreal = real star
  1641   hypnat = nat star
  1642   hcomplex = complex star
  1643 
  1644 * Hyperreal: Many groups of similarly-defined constants have been
  1645 replaced by polymorphic versions (INCOMPATIBILITY):
  1646 
  1647   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1648 
  1649   starset      <-- starsetNat, starsetC
  1650   *s*          <-- *sNat*, *sc*
  1651   starset_n    <-- starsetNat_n, starsetC_n
  1652   *sn*         <-- *sNatn*, *scn*
  1653   InternalSets <-- InternalNatSets, InternalCSets
  1654 
  1655   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1656   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1657   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1658   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1659   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1660 
  1661 * Hyperreal: Many type-specific theorems have been removed in favor of
  1662 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1663 
  1664   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1665   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1666   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1667   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1668   right_minus <-- hypreal_add_minus
  1669   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1670   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1671   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1672   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1673   mult_1_right <-- hcomplex_mult_one_right
  1674   mult_zero_left <-- hcomplex_mult_zero_left
  1675   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1676   right_distrib <-- hypnat_add_mult_distrib2
  1677   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1678   right_inverse <-- hypreal_mult_inverse
  1679   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1680   order_refl <-- {hypreal,hypnat}_le_refl
  1681   order_trans <-- {hypreal,hypnat}_le_trans
  1682   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1683   order_less_le <-- {hypreal,hypnat}_less_le
  1684   linorder_linear <-- {hypreal,hypnat}_le_linear
  1685   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1686   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1687   add_nonneg_nonneg <-- hypreal_le_add_order
  1688 
  1689 * Hyperreal: Separate theorems having to do with type-specific
  1690 versions of constants have been merged into theorems that apply to the
  1691 new polymorphic constants (INCOMPATIBILITY):
  1692 
  1693   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1694   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1695   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1696   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1697   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1698   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1699   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1700   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1701   STAR_diff <-- {STAR,STARC}_diff
  1702   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1703     STARC_hcomplex_of_complex}_image_subset
  1704   starset_n_Un <-- starset{Nat,C}_n_Un
  1705   starset_n_Int <-- starset{Nat,C}_n_Int
  1706   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1707   starset_n_diff <-- starset{Nat,C}_n_diff
  1708   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1709   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1710   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1711   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1712   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1713   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1714   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1715   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1716   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1717   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1718   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1719   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1720   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1721   starfun_diff <-- starfun{C,RC,CR}_diff
  1722   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1723   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1724   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1725   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1726   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1727   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1728   starfun_Id <-- starfunC_Id
  1729   starfun_approx <-- starfun{Nat,CR}_approx
  1730   starfun_capprox <-- starfun{C,RC}_capprox
  1731   starfun_abs <-- starfunNat_rabs
  1732   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1733   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1734   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1735   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1736   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1737   starfun_add_approx <-- starfunCR_add_approx
  1738   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1739   starfun_divide <-- starfun{C,CR,RC}_divide
  1740   starfun_n <-- starfun{Nat,C}_n
  1741   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1742   starfun_n_add <-- starfun{Nat,C}_n_add
  1743   starfun_n_add_minus <-- starfunNat_n_add_minus
  1744   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1745   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1746   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1747 
  1748   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1749   star_n_minus <-- {hypreal,hcomplex}_minus
  1750   star_n_diff <-- {hypreal,hcomplex}_diff
  1751   star_n_mult <-- {hypreal,hcomplex}_mult
  1752   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1753   star_n_le <-- {hypreal,hypnat}_le
  1754   star_n_less <-- {hypreal,hypnat}_less
  1755   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1756   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1757   star_n_abs <-- hypreal_hrabs
  1758   star_n_divide <-- hcomplex_divide
  1759 
  1760   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1761   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1762   star_of_diff <-- hypreal_of_real_diff
  1763   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1764   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1765   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1766   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1767   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1768   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1769   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1770   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1771   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1772   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1773   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1774   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1775   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1776   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1777   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1778   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1779   star_of_power <-- hypreal_of_real_power
  1780   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1781 
  1782 * Hyperreal: new method "transfer" that implements the transfer
  1783 principle of nonstandard analysis. With a subgoal that mentions
  1784 nonstandard types like "'a star", the command "apply transfer"
  1785 replaces it with an equivalent one that mentions only standard types.
  1786 To be successful, all free variables must have standard types; non-
  1787 standard variables must have explicit universal quantifiers.
  1788 
  1789 * Hyperreal: A theory of Taylor series.
  1790 
  1791 
  1792 *** HOLCF ***
  1793 
  1794 * Discontinued special version of 'constdefs' (which used to support
  1795 continuous functions) in favor of the general Pure one with full
  1796 type-inference.
  1797 
  1798 * New simplification procedure for solving continuity conditions; it
  1799 is much faster on terms with many nested lambda abstractions (cubic
  1800 instead of exponential time).
  1801 
  1802 * New syntax for domain package: selector names are now optional.
  1803 Parentheses should be omitted unless argument is lazy, for example:
  1804 
  1805   domain 'a stream = cons "'a" (lazy "'a stream")
  1806 
  1807 * New command 'fixrec' for defining recursive functions with pattern
  1808 matching; defining multiple functions with mutual recursion is also
  1809 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1810 sinr, or any data constructor defined by the domain package. The given
  1811 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1812 syntax and examples.
  1813 
  1814 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1815 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1816 but the proof obligation additionally includes an admissibility
  1817 requirement. The packages generate instances of class cpo or pcpo,
  1818 with continuity and strictness theorems for Rep and Abs.
  1819 
  1820 * HOLCF: Many theorems have been renamed according to a more standard naming
  1821 scheme (INCOMPATIBILITY):
  1822 
  1823   foo_inject:  "foo$x = foo$y ==> x = y"
  1824   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1825   foo_less:    "(foo$x << foo$y) = (x << y)"
  1826   foo_strict:  "foo$UU = UU"
  1827   foo_defined: "... ==> foo$x ~= UU"
  1828   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1829 
  1830 
  1831 *** ZF ***
  1832 
  1833 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1834 including the First Isomorphism Theorem (on quotienting by the kernel
  1835 of a homomorphism).
  1836 
  1837 * ZF/Simplifier: install second copy of type solver that actually
  1838 makes use of TC rules declared to Isar proof contexts (or locales);
  1839 the old version is still required for ML proof scripts.
  1840 
  1841 
  1842 *** Cube ***
  1843 
  1844 * Converted to Isar theory format; use locales instead of axiomatic
  1845 theories.
  1846 
  1847 
  1848 *** ML ***
  1849 
  1850 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1851 for ||>, ||>>, |>>,
  1852 
  1853 * Pure/library.ML no longer defines its own option datatype, but uses
  1854 that of the SML basis, which has constructors NONE and SOME instead of
  1855 None and Some, as well as exception Option.Option instead of OPTION.
  1856 The functions the, if_none, is_some, is_none have been adapted
  1857 accordingly, while Option.map replaces apsome.
  1858 
  1859 * Pure/library.ML: the exception LIST has been given up in favour of
  1860 the standard exceptions Empty and Subscript, as well as
  1861 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1862 superceded by the standard hd and tl functions etc.
  1863 
  1864 A number of basic list functions are no longer exported to the ML
  1865 toplevel, as they are variants of predefined functions.  The following
  1866 suggests how one can translate existing code:
  1867 
  1868     rev_append xs ys = List.revAppend (xs, ys)
  1869     nth_elem (i, xs) = List.nth (xs, i)
  1870     last_elem xs = List.last xs
  1871     flat xss = List.concat xss
  1872     seq fs = List.app fs
  1873     partition P xs = List.partition P xs
  1874     mapfilter f xs = List.mapPartial f xs
  1875 
  1876 * Pure/library.ML: several combinators for linear functional
  1877 transformations, notably reverse application and composition:
  1878 
  1879   x |> f                f #> g
  1880   (x, y) |-> f          f #-> g
  1881 
  1882 * Pure/library.ML: introduced/changed precedence of infix operators:
  1883 
  1884   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1885   infix 2 ?;
  1886   infix 3 o oo ooo oooo;
  1887   infix 4 ~~ upto downto;
  1888 
  1889 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1890 infix operators.
  1891 
  1892 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1893 fold_map support linear functional transformations and nesting.  For
  1894 example:
  1895 
  1896   fold f [x1, ..., xN] y =
  1897     y |> f x1 |> ... |> f xN
  1898 
  1899   (fold o fold) f [xs1, ..., xsN] y =
  1900     y |> fold f xs1 |> ... |> fold f xsN
  1901 
  1902   fold f [x1, ..., xN] =
  1903     f x1 #> ... #> f xN
  1904 
  1905   (fold o fold) f [xs1, ..., xsN] =
  1906     fold f xs1 #> ... #> fold f xsN
  1907 
  1908 * Pure/library.ML: the following selectors on type 'a option are
  1909 available:
  1910 
  1911   the:               'a option -> 'a  (*partial*)
  1912   these:             'a option -> 'a  where 'a = 'b list
  1913   the_default: 'a -> 'a option -> 'a
  1914   the_list:          'a option -> 'a list
  1915 
  1916 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1917 basic operations for association lists, following natural argument
  1918 order; moreover the explicit equality predicate passed here avoids
  1919 potentially expensive polymorphic runtime equality checks.
  1920 The old functions may be expressed as follows:
  1921 
  1922   assoc = uncurry (AList.lookup (op =))
  1923   assocs = these oo AList.lookup (op =)
  1924   overwrite = uncurry (AList.update (op =)) o swap
  1925 
  1926 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1927 
  1928   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1929   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1930 
  1931 replacing make_keylist and keyfilter (occassionally used)
  1932 Naive rewrites:
  1933 
  1934   make_keylist = AList.make
  1935   keyfilter = AList.find (op =)
  1936 
  1937 * eq_fst and eq_snd now take explicit equality parameter, thus
  1938   avoiding eqtypes. Naive rewrites:
  1939 
  1940     eq_fst = eq_fst (op =)
  1941     eq_snd = eq_snd (op =)
  1942 
  1943 * Removed deprecated apl and apr (rarely used).
  1944   Naive rewrites:
  1945 
  1946     apl (n, op) =>>= curry op n
  1947     apr (op, m) =>>= fn n => op (n, m)
  1948 
  1949 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1950 provides a reasonably efficient light-weight implementation of sets as
  1951 lists.
  1952 
  1953 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1954 few new operations; existing lookup and update are now curried to
  1955 follow natural argument order (for use with fold etc.);
  1956 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1957 
  1958 * Pure/General: output via the Isabelle channels of
  1959 writeln/warning/error etc. is now passed through Output.output, with a
  1960 hook for arbitrary transformations depending on the print_mode
  1961 (cf. Output.add_mode -- the first active mode that provides a output
  1962 function wins).  Already formatted output may be embedded into further
  1963 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1964 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1965 accommodate easy composition of diagnostic messages etc.  Programmers
  1966 rarely need to care about Output.output or Output.raw at all, with
  1967 some notable exceptions: Output.output is required when bypassing the
  1968 standard channels (writeln etc.), or in token translations to produce
  1969 properly formatted results; Output.raw is required when capturing
  1970 already output material that will eventually be presented to the user
  1971 a second time.  For the default print mode, both Output.output and
  1972 Output.raw have no effect.
  1973 
  1974 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1975 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1976 cumulative results are displayed at the end of a batch session.
  1977 
  1978 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1979 replaced by File.platform_path and File.shell_path (with appropriate
  1980 hooks).  This provides a clean interface for unusual systems where the
  1981 internal and external process view of file names are different.
  1982 
  1983 * Pure: more efficient orders for basic syntactic entities: added
  1984 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1985 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1986 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1987 orders now -- potential INCOMPATIBILITY for code that depends on a
  1988 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1989 Library.sort_strings on result).
  1990 
  1991 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1992 fold_types traverse types/terms from left to right, observing natural
  1993 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1994 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1995 
  1996 * Pure: name spaces have been refined, with significant changes of the
  1997 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1998 to extern(_table).  The plain name entry path is superceded by a
  1999 general 'naming' context, which also includes the 'policy' to produce
  2000 a fully qualified name and external accesses of a fully qualified
  2001 name; NameSpace.extend is superceded by context dependent
  2002 Sign.declare_name.  Several theory and proof context operations modify
  2003 the naming context.  Especially note Theory.restore_naming and
  2004 ProofContext.restore_naming to get back to a sane state; note that
  2005 Theory.add_path is no longer sufficient to recover from
  2006 Theory.absolute_path in particular.
  2007 
  2008 * Pure: new flags short_names (default false) and unique_names
  2009 (default true) for controlling output of qualified names.  If
  2010 short_names is set, names are printed unqualified.  If unique_names is
  2011 reset, the name prefix is reduced to the minimum required to achieve
  2012 the original result when interning again, even if there is an overlap
  2013 with earlier declarations.
  2014 
  2015 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2016 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2017 (useful for printing error messages).  INCOMPATIBILITY.
  2018 
  2019 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2020 Theory.theory are now identified, referring to the universal
  2021 Context.theory (see Pure/context.ML).  Actual signature and theory
  2022 content is managed as theory data.  The old code and interfaces were
  2023 spread over many files and structures; the new arrangement introduces
  2024 considerable INCOMPATIBILITY to gain more clarity:
  2025 
  2026   Context -- theory management operations (name, identity, inclusion,
  2027     parents, ancestors, merge, etc.), plus generic theory data;
  2028 
  2029   Sign -- logical signature and syntax operations (declaring consts,
  2030     types, etc.), plus certify/read for common entities;
  2031 
  2032   Theory -- logical theory operations (stating axioms, definitions,
  2033     oracles), plus a copy of logical signature operations (consts,
  2034     types, etc.); also a few basic management operations (Theory.copy,
  2035     Theory.merge, etc.)
  2036 
  2037 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2038 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2039 for convenience -- they merely return the theory.
  2040 
  2041 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2042 
  2043 * Pure: the Isar proof context type is already defined early in Pure
  2044 as Context.proof (note that ProofContext.context and Proof.context are
  2045 aliases, where the latter is the preferred name).  This enables other
  2046 Isabelle components to refer to that type even before Isar is present.
  2047 
  2048 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2049 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2050 any of these kinds.  For example, Sign.intern typeK is now
  2051 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2052 Theory.hide_types.  Also note that former
  2053 Theory.hide_classes/types/consts are now
  2054 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2055 internalize their arguments!  INCOMPATIBILITY.
  2056 
  2057 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2058 datatype thmref (with constructors Name and NameSelection) instead of
  2059 plain string -- INCOMPATIBILITY;
  2060 
  2061 * Pure: cases produced by proof methods specify options, where NONE
  2062 means to remove case bindings -- INCOMPATIBILITY in
  2063 (RAW_)METHOD_CASES.
  2064 
  2065 * Pure: the following operations retrieve axioms or theorems from a
  2066 theory node or theory hierarchy, respectively:
  2067 
  2068   Theory.axioms_of: theory -> (string * term) list
  2069   Theory.all_axioms_of: theory -> (string * term) list
  2070   PureThy.thms_of: theory -> (string * thm) list
  2071   PureThy.all_thms_of: theory -> (string * thm) list
  2072 
  2073 * Pure: print_tac now outputs the goal through the trace channel.
  2074 
  2075 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2076 Reference Toplevel.debug (default false) controls detailed printing
  2077 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2078 controls execution profiling -- set to 1 for time and 2 for space
  2079 (both increase the runtime).
  2080 
  2081 * Isar session: The initial use of ROOT.ML is now always timed,
  2082 i.e. the log will show the actual process times, in contrast to the
  2083 elapsed wall-clock time that the outer shell wrapper produces.
  2084 
  2085 * Simplifier: improved handling of bound variables (nameless
  2086 representation, avoid allocating new strings).  Simprocs that invoke
  2087 the Simplifier recursively should use Simplifier.inherit_bounds to
  2088 avoid local name clashes.  Failure to do so produces warnings
  2089 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2090 for further details.
  2091 
  2092 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2093 bindings for all theorems stored within a given theory; this may help
  2094 in porting non-Isar theories to Isar ones, while keeping ML proof
  2095 scripts for the time being.
  2096 
  2097 * ML operator HTML.with_charset specifies the charset begin used for
  2098 generated HTML files.  For example:
  2099 
  2100   HTML.with_charset "utf-8" use_thy "Hebrew";
  2101   HTML.with_charset "utf-8" use_thy "Chinese";
  2102 
  2103 
  2104 *** System ***
  2105 
  2106 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2107 isabelle, isatool etc.).
  2108 
  2109 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2110 isatool doc, isatool mkdir, display_drafts etc.).
  2111 
  2112 * isatool usedir: option -f allows specification of the ML file to be
  2113 used by Isabelle; default is ROOT.ML.
  2114 
  2115 * New isatool version outputs the version identifier of the Isabelle
  2116 distribution being used.
  2117 
  2118 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2119 (containing Boolean satisfiability problems) into Isabelle/HOL
  2120 theories.
  2121 
  2122 
  2123 
  2124 New in Isabelle2004 (April 2004)
  2125 --------------------------------
  2126 
  2127 *** General ***
  2128 
  2129 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2130   Replaces linorder.ML.
  2131 
  2132 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2133   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2134   (\<a>...\<z>), are now considered normal letters, and can therefore
  2135   be used anywhere where an ASCII letter (a...zA...Z) has until
  2136   now. COMPATIBILITY: This obviously changes the parsing of some
  2137   terms, especially where a symbol has been used as a binder, say
  2138   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2139   as an identifier.  Fix it by inserting a space around former
  2140   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2141   existing theory and ML files.
  2142 
  2143 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2144 
  2145 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2146   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2147   a normal (but invisible) letter. For multiple letter subscripts repeat
  2148   \<^isub> like this: x\<^isub>1\<^isub>2.
  2149 
  2150 * Pure: There are now sub-/superscripts that can span more than one
  2151   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2152   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2153   superscript. The new control characters are not identifier parts.
  2154 
  2155 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2156   content of "..." to the latex file instead of \isacntrl... . The "..."
  2157   may consist of any printable characters excluding the end bracket >.
  2158 
  2159 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2160   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2161   declare constants "final", which prevents their being given a definition
  2162   later.  It is useful for constants whose behaviour is fixed axiomatically
  2163   rather than definitionally, such as the meta-logic connectives.
  2164 
  2165 * Pure: 'instance' now handles general arities with general sorts
  2166   (i.e. intersections of classes),
  2167 
  2168 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2169   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2170   It can be changed to alter the colors/layout of generated pages.
  2171 
  2172 
  2173 *** Isar ***
  2174 
  2175 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2176   cut_tac, subgoal_tac and thin_tac:
  2177   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2178     locales are no longer forced to write Isar proof scripts.
  2179     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2180     emulations.
  2181   - INCOMPATIBILITY: names of variables to be instantiated may no
  2182     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2183     This is consistent with the instantiation attribute "where".
  2184 
  2185 * Attributes "where" and "of":
  2186   - Now take type variables of instantiated theorem into account when reading
  2187     the instantiation string.  This fixes a bug that caused instantiated
  2188     theorems to have too special types in some circumstances.
  2189   - "where" permits explicit instantiations of type variables.
  2190 
  2191 * Calculation commands "moreover" and "also" no longer interfere with
  2192   current facts ("this"), admitting arbitrary combinations with "then"
  2193   and derived forms.
  2194 
  2195 * Locales:
  2196   - Goal statements involving the context element "includes" no longer
  2197     generate theorems with internal delta predicates (those ending on
  2198     "_axioms") in the premise.
  2199     Resolve particular premise with <locale>.intro to obtain old form.
  2200   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2201     specification and "includes" elements in goal statement.
  2202   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2203     [intro?] and [elim?] (respectively) by default.
  2204   - Experimental command for instantiation of locales in proof contexts:
  2205         instantiate <label>[<attrs>]: <loc>
  2206     Instantiates locale <loc> and adds all its theorems to the current context
  2207     taking into account their attributes.  Label and attrs are optional
  2208     modifiers, like in theorem declarations.  If present, names of
  2209     instantiated theorems are qualified with <label>, and the attributes
  2210     <attrs> are applied after any attributes these theorems might have already.
  2211       If the locale has assumptions, a chained fact of the form
  2212     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2213     are derived.  The command does not support old-style locales declared
  2214     with "locale (open)".
  2215       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2216 
  2217 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2218   (Isar) contexts.
  2219 
  2220 
  2221 *** HOL ***
  2222 
  2223 * Proof import: new image HOL4 contains the imported library from
  2224   the HOL4 system with about 2500 theorems. It is imported by
  2225   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2226   can be used like any other Isabelle image.  See
  2227   HOL/Import/HOL/README for more information.
  2228 
  2229 * Simplifier:
  2230   - Much improved handling of linear and partial orders.
  2231     Reasoners for linear and partial orders are set up for type classes
  2232     "linorder" and "order" respectively, and are added to the default simpset
  2233     as solvers.  This means that the simplifier can build transitivity chains
  2234     to solve goals from the assumptions.
  2235   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2236     of blast or auto after simplification become unnecessary because the goal
  2237     is solved by simplification already.
  2238 
  2239 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2240     all proved in axiomatic type classes for semirings, rings and fields.
  2241 
  2242 * Numerics:
  2243   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2244     now formalized using the Ring_and_Field theory mentioned above.
  2245   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2246     than before, because now they are set up once in a generic manner.
  2247   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2248     Look for the general versions in Ring_and_Field (and Power if they concern
  2249     exponentiation).
  2250 
  2251 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2252 
  2253 * Records:
  2254   - Record types are now by default printed with their type abbreviation
  2255     instead of the list of all field types. This can be configured via
  2256     the reference "print_record_type_abbr".
  2257   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2258     (not enabled by default).
  2259   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2260     EX x. x = sel r to True (not enabled by default).
  2261   - Tactic "record_split_simp_tac" to split and simplify records added.
  2262 
  2263 * 'specification' command added, allowing for definition by
  2264   specification.  There is also an 'ax_specification' command that
  2265   introduces the new constants axiomatically.
  2266 
  2267 * arith(_tac) is now able to generate counterexamples for reals as well.
  2268 
  2269 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2270 
  2271 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2272   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2273 
  2274 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2275   matrix theory to linear programming.
  2276 
  2277 * Unions and Intersections:
  2278   The latex output syntax of UN and INT has been changed
  2279   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2280   i.e. the index formulae has become a subscript.
  2281   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2282 
  2283 * Unions and Intersections over Intervals:
  2284   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2285   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2286   like in normal math, and corresponding versions for < and for intersection.
  2287 
  2288 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2289   lexicographic dictonary ordering has been added as "lexord".
  2290 
  2291 * ML: the legacy theory structures Int and List have been removed. They had
  2292   conflicted with ML Basis Library structures having the same names.
  2293 
  2294 * 'refute' command added to search for (finite) countermodels.  Only works
  2295   for a fragment of HOL.  The installation of an external SAT solver is
  2296   highly recommended.  See "HOL/Refute.thy" for details.
  2297 
  2298 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2299   formulae under an assignment of free variables to random values.
  2300   In contrast to 'refute', it can deal with inductive datatypes,
  2301   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2302   for examples.
  2303 
  2304 
  2305 *** HOLCF ***
  2306 
  2307 * Streams now come with concatenation and are part of the HOLCF image
  2308 
  2309 
  2310 
  2311 New in Isabelle2003 (May 2003)
  2312 ------------------------------
  2313 
  2314 *** General ***
  2315 
  2316 * Provers/simplifier:
  2317 
  2318   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2319     Assumptions are now subject to complete mutual simplification,
  2320     not just from left to right. The simplifier now preserves
  2321     the order of assumptions.
  2322 
  2323     Potential INCOMPATIBILITY:
  2324 
  2325     -- simp sometimes diverges where the old version did
  2326        not, e.g. invoking simp on the goal
  2327 
  2328         [| P (f x); y = x; f x = f y |] ==> Q
  2329 
  2330        now gives rise to the infinite reduction sequence
  2331 
  2332         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2333 
  2334        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2335        kind of problem.
  2336 
  2337     -- Tactics combining classical reasoner and simplification (such as auto)
  2338        are also affected by this change, because many of them rely on
  2339        simp. They may sometimes diverge as well or yield a different numbers
  2340        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2341        in case of problems. Sometimes subsequent calls to the classical
  2342        reasoner will fail because a preceeding call to the simplifier too
  2343        eagerly simplified the goal, e.g. deleted redundant premises.
  2344 
  2345   - The simplifier trace now shows the names of the applied rewrite rules
  2346 
  2347   - You can limit the number of recursive invocations of the simplifier
  2348     during conditional rewriting (where the simplifie tries to solve the
  2349     conditions before applying the rewrite rule):
  2350     ML "simp_depth_limit := n"
  2351     where n is an integer. Thus you can force termination where previously
  2352     the simplifier would diverge.
  2353 
  2354   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2355 
  2356   - No longer aborts on failed congruence proof.  Instead, the
  2357     congruence is ignored.
  2358 
  2359 * Pure: New generic framework for extracting programs from constructive
  2360   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2361   as HOL/Extraction for some case studies.
  2362 
  2363 * Pure: The main goal of the proof state is no longer shown by default, only
  2364 the subgoals. This behaviour is controlled by a new flag.
  2365    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2366 (ML: Proof.show_main_goal).
  2367 
  2368 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2369 rules whose conclusion matches subgoal 1:
  2370       PG menu: Isabelle/Isar -> Show me -> matching rules
  2371 The rules are ordered by how closely they match the subgoal.
  2372 In particular, rules that solve a subgoal outright are displayed first
  2373 (or rather last, the way they are printed).
  2374 (ML: ProofGeneral.print_intros())
  2375 
  2376 * Pure: New flag trace_unify_fail causes unification to print
  2377 diagnostic information (PG: in trace buffer) when it fails. This is
  2378 useful for figuring out why single step proofs like rule, erule or
  2379 assumption failed.
  2380 
  2381 * Pure: Locale specifications now produce predicate definitions
  2382 according to the body of text (covering assumptions modulo local
  2383 definitions); predicate "loc_axioms" covers newly introduced text,
  2384 while "loc" is cumulative wrt. all included locale expressions; the
  2385 latter view is presented only on export into the global theory
  2386 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2387 on the old view without predicates;
  2388 
  2389 * Pure: predefined locales "var" and "struct" are useful for sharing
  2390 parameters (as in CASL, for example); just specify something like
  2391 ``var x + var y + struct M'' as import;
  2392 
  2393 * Pure: improved thms_containing: proper indexing of facts instead of
  2394 raw theorems; check validity of results wrt. current name space;
  2395 include local facts of proof configuration (also covers active
  2396 locales), cover fixed variables in index; may use "_" in term
  2397 specification; an optional limit for the number of printed facts may
  2398 be given (the default is 40);
  2399 
  2400 * Pure: disallow duplicate fact bindings within new-style theory files
  2401 (batch-mode only);
  2402 
  2403 * Provers: improved induct method: assumptions introduced by case
  2404 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2405 the goal statement); "foo" still refers to all facts collectively;
  2406 
  2407 * Provers: the function blast.overloaded has been removed: all constants
  2408 are regarded as potentially overloaded, which improves robustness in exchange
  2409 for slight decrease in efficiency;
  2410 
  2411 * Provers/linorder: New generic prover for transitivity reasoning over
  2412 linear orders.  Note: this prover is not efficient!
  2413 
  2414 * Isar: preview of problems to finish 'show' now produce an error
  2415 rather than just a warning (in interactive mode);
  2416 
  2417 
  2418 *** HOL ***
  2419 
  2420 * arith(_tac)
  2421 
  2422  - Produces a counter example if it cannot prove a goal.
  2423    Note that the counter example may be spurious if the goal is not a formula
  2424    of quantifier-free linear arithmetic.
  2425    In ProofGeneral the counter example appears in the trace buffer.
  2426 
  2427  - Knows about div k and mod k where k is a numeral of type nat or int.
  2428 
  2429  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2430    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2431    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2432 
  2433 * simp's arithmetic capabilities have been enhanced a bit: it now
  2434 takes ~= in premises into account (by performing a case split);
  2435 
  2436 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2437 are distributed over a sum of terms;
  2438 
  2439 * New tactic "trans_tac" and method "trans" instantiate
  2440 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2441 "<=", "<" and "=").
  2442 
  2443 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2444 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2445 
  2446 * 'typedef' command has new option "open" to suppress the set
  2447 definition;
  2448 
  2449 * functions Min and Max on finite sets have been introduced (theory
  2450 Finite_Set);
  2451 
  2452 * attribute [symmetric] now works for relations as well; it turns
  2453 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2454 
  2455 * induct over a !!-quantified statement (say !!x1..xn):
  2456   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2457 
  2458 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2459 %x. None. Warning: empty_def now refers to the previously hidden definition
  2460 of the empty set.
  2461 
  2462 * Algebra: formalization of classical algebra.  Intended as base for
  2463 any algebraic development in Isabelle.  Currently covers group theory
  2464 (up to Sylow's theorem) and ring theory (Universal Property of
  2465 Univariate Polynomials).  Contributions welcome;
  2466 
  2467 * GroupTheory: deleted, since its material has been moved to Algebra;
  2468 
  2469 * Complex: new directory of the complex numbers with numeric constants,
  2470 nonstandard complex numbers, and some complex analysis, standard and
  2471 nonstandard (Jacques Fleuriot);
  2472 
  2473 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2474 
  2475 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2476 Fleuriot);
  2477 
  2478 * Real/HahnBanach: updated and adapted to locales;
  2479 
  2480 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2481 Gray and Kramer);
  2482 
  2483 * UNITY: added the Meier-Sanders theory of progress sets;
  2484 
  2485 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2486 as abstract algorithms, instantiated to the JVM;
  2487 
  2488 * Bali: Java source language formalization. Type system, operational
  2489 semantics, axiomatic semantics. Supported language features:
  2490 classes, interfaces, objects,virtual methods, static methods,
  2491 static/instance fields, arrays, access modifiers, definite
  2492 assignment, exceptions.
  2493 
  2494 
  2495 *** ZF ***
  2496 
  2497 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2498 universe, etc.);
  2499 
  2500 * Main ZF: virtually all theories converted to new-style format;
  2501 
  2502 
  2503 *** ML ***
  2504 
  2505 * Pure: Tactic.prove provides sane interface for internal proofs;
  2506 omits the infamous "standard" operation, so this is more appropriate
  2507 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2508 
  2509 * Pure: improved error reporting of simprocs;
  2510 
  2511 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2512 up simprocs;
  2513 
  2514 
  2515 *** Document preparation ***
  2516 
  2517 * uses \par instead of \\ for line breaks in theory text. This may
  2518 shift some page breaks in large documents. To get the old behaviour
  2519 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2520 
  2521 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2522 other packages
  2523 
  2524 * \<euro> now needs package babel/greek instead of marvosym (which
  2525 broke \Rightarrow)
  2526 
  2527 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2528 textcomp package)
  2529 
  2530 
  2531 
  2532 New in Isabelle2002 (March 2002)
  2533 --------------------------------
  2534 
  2535 *** Document preparation ***
  2536 
  2537 * greatly simplified document preparation setup, including more
  2538 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2539 instructive isatool mkdir; users should basically be able to get
  2540 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2541 users may run a separate document processing stage manually like this:
  2542 "isatool usedir -D output HOL Test && isatool document Test/output";
  2543 
  2544 * theory dependency graph may now be incorporated into documents;
  2545 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2546 with \includegraphics of LaTeX;
  2547 
  2548 * proper spacing of consecutive markup elements, especially text
  2549 blocks after section headings;
  2550 
  2551 * support bold style (for single symbols only), input syntax is like
  2552 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2553 
  2554 * \<bullet> is now output as bold \cdot by default, which looks much
  2555 better in printed text;
  2556 
  2557 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2558 note that these symbols are currently unavailable in Proof General /
  2559 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2560 
  2561 * isatool latex no longer depends on changed TEXINPUTS, instead
  2562 isatool document copies the Isabelle style files to the target
  2563 location;
  2564 
  2565 
  2566 *** Isar ***
  2567 
  2568 * Pure/Provers: improved proof by cases and induction;
  2569   - 'case' command admits impromptu naming of parameters (such as
  2570     "case (Suc n)");
  2571   - 'induct' method divinates rule instantiation from the inductive
  2572     claim; no longer requires excessive ?P bindings for proper
  2573     instantiation of cases;
  2574   - 'induct' method properly enumerates all possibilities of set/type
  2575     rules; as a consequence facts may be also passed through *type*
  2576     rules without further ado;
  2577   - 'induct' method now derives symbolic cases from the *rulified*
  2578     rule (before it used to rulify cases stemming from the internal
  2579     atomized version); this means that the context of a non-atomic
  2580     statement becomes is included in the hypothesis, avoiding the
  2581     slightly cumbersome show "PROP ?case" form;
  2582   - 'induct' may now use elim-style induction rules without chaining
  2583     facts, using ``missing'' premises from the goal state; this allows
  2584     rules stemming from inductive sets to be applied in unstructured
  2585     scripts, while still benefitting from proper handling of non-atomic
  2586     statements; NB: major inductive premises need to be put first, all
  2587     the rest of the goal is passed through the induction;
  2588   - 'induct' proper support for mutual induction involving non-atomic
  2589     rule statements (uses the new concept of simultaneous goals, see
  2590     below);
  2591   - append all possible rule selections, but only use the first
  2592     success (no backtracking);
  2593   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2594   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2595   - added 'print_induct_rules' (covered by help item in recent Proof
  2596     General versions);
  2597   - moved induct/cases attributes to Pure, methods to Provers;
  2598   - generic method setup instantiated for FOL and HOL;
  2599 
  2600 * Pure: support multiple simultaneous goal statements, for example
  2601 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2602 meta-level mechanism, this acts as if several individual goals had
  2603 been stated separately; in particular common proof methods need to be
  2604 repeated in order to cover all claims; note that a single elimination
  2605 step is *not* sufficient to establish the two conjunctions, so this
  2606 fails:
  2607 
  2608   assume "A & B" then have A and B ..   (*".." fails*)
  2609 
  2610 better use "obtain" in situations as above; alternative refer to
  2611 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2612 
  2613 * Pure: proper integration with ``locales''; unlike the original
  2614 version by Florian Kammller, Isar locales package high-level proof
  2615 contexts rather than raw logical ones (e.g. we admit to include
  2616 attributes everywhere); operations on locales include merge and
  2617 rename; support for implicit arguments (``structures''); simultaneous
  2618 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2619 some examples;
  2620 
  2621 * Pure: the following commands have been ``localized'', supporting a
  2622 target locale specification "(in name)": 'lemma', 'theorem',
  2623 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2624 stored both within the locale and at the theory level (exported and
  2625 qualified by the locale name);
  2626 
  2627 * Pure: theory goals may now be specified in ``long'' form, with
  2628 ad-hoc contexts consisting of arbitrary locale elements. for example
  2629 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2630 definitions may be given, too); the result is a meta-level rule with
  2631 the context elements being discharged in the obvious way;
  2632 
  2633 * Pure: new proof command 'using' allows to augment currently used
  2634 facts after a goal statement ('using' is syntactically analogous to
  2635 'apply', but acts on the goal's facts only); this allows chained facts
  2636 to be separated into parts given before and after a claim, as in
  2637 ``from a and b have C using d and e <proof>'';
  2638 
  2639 * Pure: renamed "antecedent" case to "rule_context";
  2640 
  2641 * Pure: new 'judgment' command records explicit information about the
  2642 object-logic embedding (used by several tools internally); no longer
  2643 use hard-wired "Trueprop";
  2644 
  2645 * Pure: added 'corollary' command;
  2646 
  2647 * Pure: fixed 'token_translation' command;
  2648 
  2649 * Pure: removed obsolete 'exported' attribute;
  2650 
  2651 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2652 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2653 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2654 
  2655 * Pure: method 'atomize' presents local goal premises as object-level
  2656 statements (atomic meta-level propositions); setup controlled via
  2657 rewrite rules declarations of 'atomize' attribute; example
  2658 application: 'induct' method with proper rule statements in improper
  2659 proof *scripts*;
  2660 
  2661 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2662 now consider the syntactic context of assumptions, giving a better
  2663 chance to get type-inference of the arguments right (this is
  2664 especially important for locales);
  2665 
  2666 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2667 mode;
  2668 
  2669 * Pure/obtain: the formal conclusion "thesis", being marked as
  2670 ``internal'', may no longer be reference directly in the text;
  2671 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2672 situations;
  2673 
  2674 * Pure: generic 'sym' attribute which declares a rule both as pure
  2675 'elim?' and for the 'symmetric' operation;
  2676 
  2677 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2678 text; the fixed correlation with particular command syntax has been
  2679 discontinued;
  2680 
  2681 * Pure: new method 'rules' is particularly well-suited for proof
  2682 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2683 but often produces more compact proof terms with less detours;
  2684 
  2685 * Pure/Provers/classical: simplified integration with pure rule
  2686 attributes and methods; the classical "intro?/elim?/dest?"
  2687 declarations coincide with the pure ones; the "rule" method no longer
  2688 includes classically swapped intros; "intro" and "elim" methods no
  2689 longer pick rules from the context; also got rid of ML declarations
  2690 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2691 INCOMPATIBILITY;
  2692 
  2693 * Provers/classical: attribute 'swapped' produces classical inversions
  2694 of introduction rules;
  2695 
  2696 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2697 rules instead of full simplifier context; 'iff' attribute handles
  2698 conditional rules;
  2699 
  2700 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2701 
  2702 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2703 "(permissive)" option to recover old behavior;
  2704 
  2705 * HOL: 'inductive' no longer features separate (collective) attributes
  2706 for 'intros' (was found too confusing);
  2707 
  2708 * HOL: properly declared induction rules less_induct and
  2709 wf_induct_rule;
  2710 
  2711 
  2712 *** HOL ***
  2713 
  2714 * HOL: moved over to sane numeral syntax; the new policy is as
  2715 follows:
  2716 
  2717   - 0 and 1 are polymorphic constants, which are defined on any
  2718   numeric type (nat, int, real etc.);
  2719 
  2720   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2721   binary representation internally;
  2722 
  2723   - type nat has special constructor Suc, and generally prefers Suc 0
  2724   over 1::nat and Suc (Suc 0) over 2::nat;
  2725 
  2726 This change may cause significant problems of INCOMPATIBILITY; here
  2727 are some hints on converting existing sources:
  2728 
  2729   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2730   entities, so expressions involving "-" (unary or binary minus) need
  2731   to be spaced properly;
  2732 
  2733   - existing occurrences of "1" may need to be constraint "1::nat" or
  2734   even replaced by Suc 0; similar for old "2";
  2735 
  2736   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2737 
  2738   - remove all special provisions on numerals in proofs;
  2739 
  2740 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2741 representation (depends on bin_arith_simps in the default context);
  2742 
  2743 * HOL: symbolic syntax for x^2 (numeral 2);
  2744 
  2745 * HOL: the class of all HOL types is now called "type" rather than
  2746 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2747 in axclass/classes, instance/arities, and (usually rare) occurrences
  2748 in typings (of consts etc.); internally the class is called
  2749 "HOL.type", ML programs should refer to HOLogic.typeS;
  2750 
  2751 * HOL/record package improvements:
  2752   - new derived operations "fields" to build a partial record section,
  2753     "extend" to promote a fixed record to a record scheme, and
  2754     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2755     declared as simp by default;
  2756   - shared operations ("more", "fields", etc.) now need to be always
  2757     qualified) --- potential INCOMPATIBILITY;
  2758   - removed "make_scheme" operations (use "make" with "extend") --
  2759     INCOMPATIBILITY;
  2760   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2761   - provides cases/induct rules for use with corresponding Isar
  2762     methods (for concrete records, record schemes, concrete more
  2763     parts, and schematic more parts -- in that order);
  2764   - internal definitions directly based on a light-weight abstract
  2765     theory of product types over typedef rather than datatype;
  2766 
  2767 * HOL: generic code generator for generating executable ML code from
  2768 specifications; specific support for HOL constructs such as inductive
  2769 datatypes and sets, as well as recursive functions; can be invoked
  2770 via 'generate_code' theory section;
  2771 
  2772 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2773 
  2774 * HOL: consolidated and renamed several theories.  In particular:
  2775         Ord.thy has been absorbed into HOL.thy
  2776         String.thy has been absorbed into List.thy
  2777 
  2778 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2779 (beware of argument permutation!);
  2780 
  2781 * HOL: linorder_less_split superseded by linorder_cases;
  2782 
  2783 * HOL/List: "nodups" renamed to "distinct";
  2784 
  2785 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2786 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2787   - Ex_def has changed, now need to use some_eq_ex
  2788 
  2789 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2790 in this (rare) case use:
  2791 
  2792   delSWrapper "split_all_tac"
  2793   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2794 
  2795 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2796 MAY FAIL;
  2797 
  2798 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2799 Isabelle's type classes, ^ on functions and relations has too general
  2800 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2801 necessary to attach explicit type constraints;
  2802 
  2803 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2804 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2805 renamed accordingly (eg "compI" -> "rel_compI").
  2806 
  2807 * HOL: syntax translations now work properly with numerals and records
  2808 expressions;
  2809 
  2810 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2811 of "lam" -- INCOMPATIBILITY;
  2812 
  2813 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2814 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2815 renamed "Product_Type.unit";
  2816 
  2817 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2818 
  2819 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2820 the "cases" method);
  2821 
  2822 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2823 Florian Kammller);
  2824 
  2825 * HOL/IMP: updated and converted to new-style theory format; several
  2826 parts turned into readable document, with proper Isar proof texts and
  2827 some explanations (by Gerwin Klein);
  2828 
  2829 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2830 
  2831 * HOL-Hyperreal is now a logic image;
  2832 
  2833 
  2834 *** HOLCF ***
  2835 
  2836 * Isar: consts/constdefs supports mixfix syntax for continuous
  2837 operations;
  2838 
  2839 * Isar: domain package adapted to new-style theory format, e.g. see
  2840 HOLCF/ex/Dnat.thy;
  2841 
  2842 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2843 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2844 lift.induct_tac, always use UU instead of Undef;
  2845 
  2846 * HOLCF/IMP: updated and converted to new-style theory;
  2847 
  2848 
  2849 *** ZF ***
  2850 
  2851 * Isar: proper integration of logic-specific tools and packages,
  2852 including theory commands '(co)inductive', '(co)datatype',
  2853 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2854 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2855 
  2856 * theory Main no longer includes AC; for the Axiom of Choice, base
  2857 your theory on Main_ZFC;
  2858 
  2859 * the integer library now covers quotients and remainders, with many
  2860 laws relating division to addition, multiplication, etc.;
  2861 
  2862 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2863 typeless version of the formalism;
  2864 
  2865 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2866 format;
  2867 
  2868 * ZF/Induct: new directory for examples of inductive definitions,
  2869 including theory Multiset for multiset orderings; converted to
  2870 new-style theory format;
  2871 
  2872 * ZF: many new theorems about lists, ordinals, etc.;
  2873 
  2874 
  2875 *** General ***
  2876 
  2877 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2878 variable proof controls level of detail: 0 = no proofs (only oracle
  2879 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2880 also ref manual for further ML interfaces;
  2881 
  2882 * Pure/axclass: removed obsolete ML interface
  2883 goal_subclass/goal_arity;
  2884 
  2885 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2886 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2887 separate tokens, so expressions involving minus need to be spaced
  2888 properly;
  2889 
  2890 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2891 rather than "infixl" or "infixr";
  2892 
  2893 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2894 sort constraint specifications in type inference; e.g. "x::_::foo"
  2895 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2896 type variable);
  2897 
  2898 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2899 control output of nested => (types); the default behavior is
  2900 "type_brackets";
  2901 
  2902 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2903 tokens into AST constants;
  2904 
  2905 * Pure/syntax: prefer later declarations of translations and print
  2906 translation functions; potential INCOMPATIBILITY: need to reverse
  2907 multiple declarations for same syntax element constant;
  2908 
  2909 * Pure/show_hyps reset by default (in accordance to existing Isar
  2910 practice);
  2911 
  2912 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2913 addSafter;
  2914 
  2915 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2916 as well;
  2917 
  2918 * system: tested support for MacOS X; should be able to get Isabelle +
  2919 Proof General to work in a plain Terminal after installing Poly/ML
  2920 (e.g. from the Isabelle distribution area) and GNU bash alone
  2921 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2922 support requires further installations, e.g. from
  2923 http://fink.sourceforge.net/);
  2924 
  2925 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2926 
  2927 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2928 of 40 MB), cf. ML_OPTIONS;
  2929 
  2930 * system: Proof General keywords specification is now part of the
  2931 Isabelle distribution (see etc/isar-keywords.el);
  2932 
  2933 * system: support for persistent Proof General sessions (refrain from
  2934 outdating all loaded theories on startup); user may create writable
  2935 logic images like this: ``isabelle -q HOL Test'';
  2936 
  2937 * system: smart selection of Isabelle process versus Isabelle
  2938 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2939 run both "isabelle" and "Isabelle" even if file names are badly
  2940 damaged (executable inspects the case of the first letter of its own
  2941 name); added separate "isabelle-process" and "isabelle-interface";
  2942 
  2943 * system: refrain from any attempt at filtering input streams; no
  2944 longer support ``8bit'' encoding of old isabelle font, instead proper
  2945 iso-latin characters may now be used; the related isatools
  2946 "symbolinput" and "nonascii" have disappeared as well;
  2947 
  2948 * system: removed old "xterm" interface (the print modes "xterm" and
  2949 "xterm_color" are still available for direct use in a suitable
  2950 terminal);
  2951 
  2952 
  2953 
  2954 New in Isabelle99-2 (February 2001)
  2955 -----------------------------------
  2956 
  2957 *** Overview of INCOMPATIBILITIES ***
  2958 
  2959 * HOL: please note that theories in the Library and elsewhere often use the
  2960 new-style (Isar) format; to refer to their theorems in an ML script you must
  2961 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2962 
  2963 * HOL: inductive package no longer splits induction rule aggressively,
  2964 but only as far as specified by the introductions given; the old
  2965 format may be recovered via ML function complete_split_rule or attribute
  2966 'split_rule (complete)';
  2967 
  2968 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2969 gfp_Tarski to gfp_unfold;
  2970 
  2971 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2972 
  2973 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2974 relation); infix "^^" has been renamed "``"; infix "``" has been
  2975 renamed "`"; "univalent" has been renamed "single_valued";
  2976 
  2977 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2978 operation;
  2979 
  2980 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2981 
  2982 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2983 
  2984 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2985 consequence, it is no longer monotonic wrt. the local goal context
  2986 (which is now passed through the inductive cases);
  2987 
  2988 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2989 \<gg> to \<ggreater>;
  2990 
  2991 
  2992 *** Document preparation ***
  2993 
  2994 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2995 available: are "it" for near math-mode best-style output, "sl" for
  2996 slanted text style, and "tt" for plain type-writer; if no
  2997 \isabellestyle command is given, output is according to slanted
  2998 type-writer);
  2999 
  3000 * support sub/super scripts (for single symbols only), input syntax is
  3001 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3002 
  3003 * some more standard symbols; see Appendix A of the system manual for
  3004 the complete list of symbols defined in isabellesym.sty;
  3005 
  3006 * improved isabelle style files; more abstract symbol implementation
  3007 (should now use \isamath{...} and \isatext{...} in custom symbol
  3008 definitions);
  3009 
  3010 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3011 state; Note that presentation of goal states does not conform to
  3012 actual human-readable proof documents.  Please do not include goal
  3013 states into document output unless you really know what you are doing!
  3014 
  3015 * proper indentation of antiquoted output with proportional LaTeX
  3016 fonts;
  3017 
  3018 * no_document ML operator temporarily disables LaTeX document
  3019 generation;
  3020 
  3021 * isatool unsymbolize tunes sources for plain ASCII communication;
  3022 
  3023 
  3024 *** Isar ***
  3025 
  3026 * Pure: Isar now suffers initial goal statements to contain unbound
  3027 schematic variables (this does not conform to actual readable proof
  3028 documents, due to unpredictable outcome and non-compositional proof
  3029 checking); users who know what they are doing may use schematic goals
  3030 for Prolog-style synthesis of proven results;
  3031 
  3032 * Pure: assumption method (an implicit finishing) now handles actual
  3033 rules as well;
  3034 
  3035 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3036 initial goal, declare "that" only as Pure intro (only for single
  3037 steps); the "that" rule assumption may now be involved in implicit
  3038 finishing, thus ".." becomes a feasible for trivial obtains;
  3039 
  3040 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3041 instance proofs may be performed by "..";
  3042 
  3043 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3044 statements as well;
  3045 
  3046 * Pure: more robust selection of calculational rules;
  3047 
  3048 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3049 rule (as well as the assumption rule);
  3050 
  3051 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3052 lemmas, using the graph browser tool;
  3053 
  3054 * Pure: predict failure of "show" in interactive mode;
  3055 
  3056 * Pure: 'thms_containing' now takes actual terms as arguments;
  3057 
  3058 * HOL: improved method 'induct' --- now handles non-atomic goals
  3059 (potential INCOMPATIBILITY); tuned error handling;
  3060 
  3061 * HOL: cases and induct rules now provide explicit hints about the
  3062 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3063 any remaining facts are inserted into the goal verbatim;
  3064 
  3065 * HOL: local contexts (aka cases) may now contain term bindings as
  3066 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3067 the result to be shown in each case;
  3068 
  3069 * HOL: added 'recdef_tc' command;
  3070 
  3071 * isatool convert assists in eliminating legacy ML scripts;
  3072 
  3073 
  3074 *** HOL ***
  3075 
  3076 * HOL/Library: a collection of generic theories to be used together
  3077 with main HOL; the theory loader path already includes this directory
  3078 by default; the following existing theories have been moved here:
  3079 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3080 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3081 
  3082 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3083 modelling and verification task performed in Isabelle/HOL +
  3084 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3085 
  3086 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3087 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3088 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3089 'domain', this makes the theory consistent with mathematical
  3090 literature;
  3091 
  3092 * HOL basics: added overloaded operations "inverse" and "divide"
  3093 (infix "/"), syntax for generic "abs" operation, generic summation
  3094 operator \<Sum>;
  3095 
  3096 * HOL/typedef: simplified package, provide more useful rules (see also
  3097 HOL/subset.thy);
  3098 
  3099 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3100 now expressed as a proper nested rule (old-style tactic scripts may
  3101 require atomize_strip_tac to cope with non-atomic premises);
  3102 
  3103 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3104 to "split_conv" (old name still available for compatibility);
  3105 
  3106 * HOL: improved concrete syntax for strings (e.g. allows translation
  3107 rules with string literals);
  3108 
  3109 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3110  and Fleuriot's mechanization of analysis, including the transcendental
  3111  functions for the reals;
  3112 
  3113 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3114 
  3115 
  3116 *** CTT ***
  3117 
  3118 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3119 "lam" is displayed as TWO lambda-symbols
  3120 
  3121 * CTT: theory Main now available, containing everything (that is, Bool
  3122 and Arith);
  3123 
  3124 
  3125 *** General ***
  3126 
  3127 * Pure: the Simplifier has been implemented properly as a derived rule
  3128 outside of the actual kernel (at last!); the overall performance
  3129 penalty in practical applications is about 50%, while reliability of
  3130 the Isabelle inference kernel has been greatly improved;
  3131 
  3132 * print modes "brackets" and "no_brackets" control output of nested =>
  3133 (types) and ==> (props); the default behaviour is "brackets";
  3134 
  3135 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3136 as assumptions as well;
  3137 
  3138 * system: support Poly/ML 4.0;
  3139 
  3140 * system: isatool install handles KDE version 1 or 2;
  3141 
  3142 
  3143 
  3144 New in Isabelle99-1 (October 2000)
  3145 ----------------------------------
  3146 
  3147 *** Overview of INCOMPATIBILITIES ***
  3148 
  3149 * HOL: simplification of natural numbers is much changed; to partly
  3150 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3151 issue the following ML commands:
  3152 
  3153   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3154   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3155 
  3156 * HOL: simplification no longer dives into case-expressions; this is
  3157 controlled by "t.weak_case_cong" for each datatype t;
  3158 
  3159 * HOL: nat_less_induct renamed to less_induct;
  3160 
  3161 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3162 fixsome to patch .thy and .ML sources automatically;
  3163 
  3164   select_equality  -> some_equality
  3165   select_eq_Ex     -> some_eq_ex
  3166   selectI2EX       -> someI2_ex
  3167   selectI2         -> someI2
  3168   selectI          -> someI
  3169   select1_equality -> some1_equality
  3170   Eps_sym_eq       -> some_sym_eq_trivial
  3171   Eps_eq           -> some_eq_trivial
  3172 
  3173 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3174 
  3175 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3176 instead);
  3177 
  3178 * HOL: the recursion equations generated by 'recdef' are now called
  3179 f.simps instead of f.rules;
  3180 
  3181 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3182 
  3183 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3184 sometimes be needed;
  3185 
  3186 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3187 
  3188 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3189 
  3190 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3191 product is now "<*>" instead of "Times"; the lexicographic product is
  3192 now "<*lex*>" instead of "**";
  3193 
  3194 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3195 of main HOL, but was unused); better use HOL's datatype package;
  3196 
  3197 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3198 the old syntax may be recovered as follows:
  3199 
  3200   syntax (symbols)
  3201     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3202       (infixl "\\<oplus>" 100)
  3203 
  3204 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3205 
  3206 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3207 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3208 internally;
  3209 
  3210 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3211 changed from A/r to A//r;
  3212 
  3213 * ZF: new treatment of arithmetic (nat & int) may break some old
  3214 proofs;
  3215 
  3216 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3217 rulify -> rule_format, elimify -> elim_format, ...);
  3218 
  3219 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3220 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3221 should have to change intro!! to intro? only); replaced "delrule" by
  3222 "rule del";
  3223 
  3224 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3225 
  3226 * Provers: strengthened force_tac by using new first_best_tac;
  3227 
  3228 * LaTeX document preparation: several changes of isabelle.sty (see
  3229 lib/texinputs);
  3230 
  3231 
  3232 *** Document preparation ***
  3233 
  3234 * formal comments (text blocks etc.) in new-style theories may now
  3235 contain antiquotations of thm/prop/term/typ/text to be presented
  3236 according to latex print mode; concrete syntax is like this:
  3237 @{term[show_types] "f(x) = a + x"};
  3238 
  3239 * isatool mkdir provides easy setup of Isabelle session directories,
  3240 including proper document sources;
  3241 
  3242 * generated LaTeX sources are now deleted after successful run
  3243 (isatool document -c); may retain a copy somewhere else via -D option
  3244 of isatool usedir;
  3245 
  3246 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3247 style files, achieving self-contained LaTeX sources and simplifying
  3248 LaTeX debugging;
  3249 
  3250 * old-style theories now produce (crude) LaTeX output as well;
  3251 
  3252 * browser info session directories are now self-contained (may be put
  3253 on WWW server seperately); improved graphs of nested sessions; removed
  3254 graph for 'all sessions';
  3255 
  3256 * several improvements in isabelle style files; \isabellestyle{it}
  3257 produces fake math mode output; \isamarkupheader is now \section by
  3258 default; see lib/texinputs/isabelle.sty etc.;
  3259 
  3260 
  3261 *** Isar ***
  3262 
  3263 * Isar/Pure: local results and corresponding term bindings are now
  3264 subject to Hindley-Milner polymorphism (similar to ML); this
  3265 accommodates incremental type-inference very nicely;
  3266 
  3267 * Isar/Pure: new derived language element 'obtain' supports
  3268 generalized existence reasoning;
  3269 
  3270 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3271 support accumulation of results, without applying any rules yet;
  3272 useful to collect intermediate results without explicit name
  3273 references, and for use with transitivity rules with more than 2
  3274 premises;
  3275 
  3276 * Isar/Pure: scalable support for case-analysis type proofs: new
  3277 'case' language element refers to local contexts symbolically, as
  3278 produced by certain proof methods; internally, case names are attached
  3279 to theorems as "tags";
  3280 
  3281 * Isar/Pure: theory command 'hide' removes declarations from
  3282 class/type/const name spaces;
  3283 
  3284 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3285 indicate potential overloading;
  3286 
  3287 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3288 
  3289 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3290 "{a,b,c}" instead of {a,b,c};
  3291 
  3292 * Isar/Pure now provides its own version of intro/elim/dest
  3293 attributes; useful for building new logics, but beware of confusion
  3294 with the version in Provers/classical;
  3295 
  3296 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3297 case name 'antecedent';
  3298 
  3299 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3300 to the current context is now done automatically);
  3301 
  3302 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3303 for definining proof methods in ML;
  3304 
  3305 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3306 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3307 most cases, one should have to change intro!! to intro? only);
  3308 replaced "delrule" by "rule del";
  3309 
  3310 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3311 'symmetric' attribute (the latter supercedes [RS sym]);
  3312 
  3313 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3314 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3315 well (including splits);
  3316 
  3317 * Isar/Provers: Simplifier and Classical methods now support all kind
  3318 of modifiers used in the past, including 'cong', 'iff', etc.
  3319 
  3320 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3321 of Simplifier and Classical reasoner);
  3322 
  3323 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3324 now support named cases; major packages (inductive, datatype, primrec,
  3325 recdef) support case names and properly name parameters;
  3326 
  3327 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3328 monotonicity conditions are extracted to be proven at end of
  3329 calculations;
  3330 
  3331 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3332 method anyway;
  3333 
  3334 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3335 split_if split_if_asm; datatype package provides theorems foo.splits =
  3336 foo.split foo.split_asm for each datatype;
  3337 
  3338 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3339 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3340 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3341 use "(cases (simplified))" method in proper proof texts);
  3342 
  3343 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3344 
  3345 * Isar: names of theorems etc. may be natural numbers as well;
  3346 
  3347 * Isar: 'pr' command: optional arguments for goals_limit and
  3348 ProofContext.prems_limit; no longer prints theory contexts, but only
  3349 proof states;
  3350 
  3351 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3352 additional print modes to be specified; e.g. "pr(latex)" will print
  3353 proof state according to the Isabelle LaTeX style;
  3354 
  3355 * Isar: improved support for emulating tactic scripts, including proof
  3356 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3357 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3358 (for HOL datatypes);
  3359 
  3360 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3361 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3362 'proof method scripts' have to be in depth-first order;
  3363 
  3364 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3365 
  3366 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3367 should instead use individual commands for printing items
  3368 (print_commands, print_methods etc.);
  3369 
  3370 * Isar: added 'nothing' --- the empty list of theorems;
  3371 
  3372 
  3373 *** HOL ***
  3374 
  3375 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3376 corresponding virtual machine and a specification of its bytecode
  3377 verifier and a lightweight bytecode verifier, including proofs of
  3378 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3379 Cornelia Pusch (see also the homepage of project Bali at
  3380 http://isabelle.in.tum.de/Bali/);
  3381 
  3382 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3383 Clemens Ballarin;
  3384 
  3385 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3386 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3387 Rasmussen;
  3388 
  3389 * HOL/Lattice: fundamental concepts of lattice theory and order
  3390 structures, including duals, properties of bounds versus algebraic
  3391 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3392 Theorem for complete lattices etc.; may also serve as a demonstration
  3393 for abstract algebraic reasoning using axiomatic type classes, and
  3394 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3395 
  3396 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3397 von Oheimb;
  3398 
  3399 * HOL/IMPP: extension of IMP with local variables and mutually
  3400 recursive procedures, by David von Oheimb;
  3401 
  3402 * HOL/Lambda: converted into new-style theory and document;
  3403 
  3404 * HOL/ex/Multiquote: example of multiple nested quotations and
  3405 anti-quotations -- basically a generalized version of de-Bruijn
  3406 representation; very useful in avoiding lifting of operations;
  3407 
  3408 * HOL/record: added general record equality rule to simpset; fixed
  3409 select-update simplification procedure to handle extended records as
  3410 well; admit "r" as field name;
  3411 
  3412 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3413 other numeric types and also as the identity of groups, rings, etc.;
  3414 
  3415 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3416 Types nat and int belong to this axclass;
  3417 
  3418 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3419    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3420    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3421   two terms #m*u and #n*u are replaced by #(m+n)*u
  3422     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3423   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3424     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3425 
  3426 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3427 powerful prover for predicate logic but knows nothing of clasets; see
  3428 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3429 
  3430 * HOL: new version of "case_tac" subsumes both boolean case split and
  3431 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3432 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3433 
  3434 * HOL: simplification no longer dives into case-expressions: only the
  3435 selector expression is simplified, but not the remaining arms; to
  3436 enable full simplification of case-expressions for datatype t, you may
  3437 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3438 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3439 
  3440 * HOL/recdef: the recursion equations generated by 'recdef' for
  3441 function 'f' are now called f.simps instead of f.rules; if all
  3442 termination conditions are proved automatically, these simplification
  3443 rules are added to the simpset, as in primrec; rules may be named
  3444 individually as well, resulting in a separate list of theorems for
  3445 each equation;
  3446 
  3447 * HOL/While is a new theory that provides a while-combinator. It
  3448 permits the definition of tail-recursive functions without the
  3449 provision of a termination measure. The latter is necessary once the
  3450 invariant proof rule for while is applied.
  3451 
  3452 * HOL: new (overloaded) notation for the set of elements below/above
  3453 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3454 
  3455 * HOL: theorems impI, allI, ballI bound as "strip";
  3456 
  3457 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3458 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3459 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3460 
  3461 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3462 
  3463 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3464 main HOL, but was unused);
  3465 
  3466 * HOL: fewer consts declared as global (e.g. have to refer to
  3467 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3468 
  3469 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3470 in case of overlap with user translations (e.g. judgements over
  3471 tuples); (note that the underlying logical represenation is still
  3472 bogus);
  3473 
  3474 
  3475 *** ZF ***
  3476 
  3477 * ZF: simplification automatically cancels common terms in arithmetic
  3478 expressions over nat and int;
  3479 
  3480 * ZF: new treatment of nat to minimize type-checking: all operators
  3481 coerce their operands to a natural number using the function natify,
  3482 making the algebraic laws unconditional;
  3483 
  3484 * ZF: as above, for int: operators coerce their operands to an integer
  3485 using the function intify;
  3486 
  3487 * ZF: the integer library now contains many of the usual laws for the
  3488 orderings, including $<=, and monotonicity laws for $+ and $*;
  3489 
  3490 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3491 simplification;
  3492 
  3493 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3494 to the simplifier and classical reasoner simultaneously;
  3495 
  3496 
  3497 *** General ***
  3498 
  3499 * Provers: blast_tac now handles actual object-logic rules as
  3500 assumptions; note that auto_tac uses blast_tac internally as well;
  3501 
  3502 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3503 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3504 
  3505 * Provers: delrules now handles destruct rules as well (no longer need
  3506 explicit make_elim);
  3507 
  3508 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3509   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3510 use instead the strong form,
  3511   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3512 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3513 from destruct-rules;
  3514 
  3515 * Provers: Simplifier.easy_setup provides a fast path to basic
  3516 Simplifier setup for new object-logics;
  3517 
  3518 * Pure: AST translation rules no longer require constant head on LHS;
  3519 
  3520 * Pure: improved name spaces: ambiguous output is qualified; support
  3521 for hiding of names;
  3522 
  3523 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3524 XSYMBOL_HOME; no longer need to do manual configuration in most
  3525 situations;
  3526 
  3527 * system: compression of ML heaps images may now be controlled via -c
  3528 option of isabelle and isatool usedir (currently only observed by
  3529 Poly/ML);
  3530 
  3531 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3532 useful for remote X11);
  3533 
  3534 * system: provide TAGS file for Isabelle sources;
  3535 
  3536 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3537 order;
  3538 
  3539 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3540 timing flag supersedes proof_timing and Toplevel.trace;
  3541 
  3542 * ML: new combinators |>> and |>>> for incremental transformations
  3543 with secondary results (e.g. certain theory extensions):
  3544 
  3545 * ML: PureThy.add_defs gets additional argument to indicate potential
  3546 overloading (usually false);
  3547 
  3548 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3549 results;
  3550 
  3551 
  3552 
  3553 New in Isabelle99 (October 1999)
  3554 --------------------------------
  3555 
  3556 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3557 
  3558 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3559 are no longer simplified.  (This allows the simplifier to unfold recursive
  3560 functional programs.)  To restore the old behaviour, declare
  3561 
  3562     Delcongs [if_weak_cong];
  3563 
  3564 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3565 complement;
  3566 
  3567 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3568 
  3569 * HOL/datatype: mutual_induct_tac no longer exists --
  3570   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3571 
  3572 * HOL/typedef: fixed type inference for representing set; type
  3573 arguments now have to occur explicitly on the rhs as type constraints;
  3574 
  3575 * ZF: The con_defs part of an inductive definition may no longer refer
  3576 to constants declared in the same theory;
  3577 
  3578 * HOL, ZF: the function mk_cases, generated by the inductive
  3579 definition package, has lost an argument.  To simplify its result, it
  3580 uses the default simpset instead of a supplied list of theorems.
  3581 
  3582 * HOL/List: the constructors of type list are now Nil and Cons;
  3583 
  3584 * Simplifier: the type of the infix ML functions
  3585         setSSolver addSSolver setSolver addSolver
  3586 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3587 for packaging solvers. A solver is created via
  3588         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3589 where the string argument is only a comment.
  3590 
  3591 
  3592 *** Proof tools ***
  3593 
  3594 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3595 decision procedure for linear arithmetic. Currently it is used for
  3596 types `nat', `int', and `real' in HOL (see below); it can, should and
  3597 will be instantiated for other types and logics as well.
  3598 
  3599 * The simplifier now accepts rewrite rules with flexible heads, eg
  3600      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3601   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3602   matching.
  3603 
  3604 
  3605 *** General ***
  3606 
  3607 * New Isabelle/Isar subsystem provides an alternative to traditional
  3608 tactical theorem proving; together with the ProofGeneral/isar user
  3609 interface it offers an interactive environment for developing human
  3610 readable proof documents (Isar == Intelligible semi-automated
  3611 reasoning); for further information see isatool doc isar-ref,
  3612 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3613 
  3614 * improved and simplified presentation of theories: better HTML markup
  3615 (including colors), graph views in several sizes; isatool usedir now
  3616 provides a proper interface for user theories (via -P option); actual
  3617 document preparation based on (PDF)LaTeX is available as well (for
  3618 new-style theories only); see isatool doc system for more information;
  3619 
  3620 * native support for Proof General, both for classic Isabelle and
  3621 Isabelle/Isar;
  3622 
  3623 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3624 using the graph browser tool;
  3625 
  3626 * Isabelle manuals now also available as PDF;
  3627 
  3628 * theory loader rewritten from scratch (may not be fully
  3629 bug-compatible); old loadpath variable has been replaced by show_path,
  3630 add_path, del_path, reset_path functions; new operations such as
  3631 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3632 isatool doc ref);
  3633 
  3634 * improved isatool install: option -k creates KDE application icon,
  3635 option -p DIR installs standalone binaries;
  3636 
  3637 * added ML_PLATFORM setting (useful for cross-platform installations);
  3638 more robust handling of platform specific ML images for SML/NJ;
  3639 
  3640 * the settings environment is now statically scoped, i.e. it is never
  3641 created again in sub-processes invoked from isabelle, isatool, or
  3642 Isabelle;
  3643 
  3644 * path element specification '~~' refers to '$ISABELLE_HOME';
  3645 
  3646 * in locales, the "assumes" and "defines" parts may be omitted if
  3647 empty;
  3648 
  3649 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3650 long arrows);
  3651 
  3652 * new print_mode "HTML";
  3653 
  3654 * new flag show_tags controls display of tags of theorems (which are
  3655 basically just comments that may be attached by some tools);
  3656 
  3657 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3658 mode and goal output format:
  3659 
  3660 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3661 244c244
  3662 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3663 ---
  3664 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3665 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3666 181c181
  3667 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3668 ---
  3669 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3670 
  3671 * function bind_thms stores lists of theorems (cf. bind_thm);
  3672 
  3673 * new shorthand tactics ftac, eatac, datac, fatac;
  3674 
  3675 * qed (and friends) now accept "" as result name; in that case the
  3676 theorem is not stored, but proper checks and presentation of the
  3677 result still apply;
  3678 
  3679 * theorem database now also indexes constants "Trueprop", "all",
  3680 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3681 
  3682 
  3683 *** HOL ***
  3684 
  3685 ** HOL arithmetic **
  3686 
  3687 * There are now decision procedures for linear arithmetic over nat and
  3688 int:
  3689 
  3690 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3691 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3692 are treated as atomic; subformulae not involving type `nat' or `int'
  3693 are ignored; quantified subformulae are ignored unless they are
  3694 positive universal or negative existential. The tactic has to be
  3695 invoked by hand and can be a little bit slow. In particular, the
  3696 running time is exponential in the number of occurrences of `min' and
  3697 `max', and `-' on `nat'.
  3698 
  3699 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3700 (negated) (in)equalities among the premises and the conclusion into
  3701 account (i.e. no compound formulae) and does not know about `min' and
  3702 `max', and `-' on `nat'. It is fast and is used automatically by the
  3703 simplifier.
  3704 
  3705 NB: At the moment, these decision procedures do not cope with mixed
  3706 nat/int formulae where the two parts interact, such as `m < n ==>
  3707 int(m) < int(n)'.
  3708 
  3709 * HOL/Numeral provides a generic theory of numerals (encoded
  3710 efficiently as bit strings); setup for types nat/int/real is in place;
  3711 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3712 int, existing theories and proof scripts may require a few additional
  3713 type constraints;
  3714 
  3715 * integer division and remainder can now be performed on constant
  3716 arguments;
  3717 
  3718 * many properties of integer multiplication, division and remainder
  3719 are now available;
  3720 
  3721 * An interface to the Stanford Validity Checker (SVC) is available through the
  3722 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3723 are proved automatically.  SVC must be installed separately, and its results
  3724 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3725 invocation of the underlying oracle).  For SVC see
  3726   http://verify.stanford.edu/SVC
  3727 
  3728 * IsaMakefile: the HOL-Real target now builds an actual image;
  3729 
  3730 
  3731 ** HOL misc **
  3732 
  3733 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3734 (in Isabelle/Isar) -- by Gertrud Bauer;
  3735 
  3736 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3737 analysis for assembly languages with subtypes;
  3738 
  3739 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3740 -- avoids syntactic ambiguities and treats state, transition, and
  3741 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3742 changed syntax and (many) tactics;
  3743 
  3744 * HOL/inductive: Now also handles more general introduction rules such
  3745   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3746   theorems are now maintained within the theory (maintained via the
  3747   "mono" attribute);
  3748 
  3749 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3750   (using function types) such as
  3751 
  3752   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3753 
  3754 * HOL/record: record_simproc (part of the default simpset) takes care
  3755 of selectors applied to updated records; record_split_tac is no longer
  3756 part of the default claset; update_defs may now be removed from the
  3757 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3758 
  3759   claset_ref () := claset() addSWrapper record_split_wrapper;
  3760   Delsimprocs [record_simproc]
  3761 
  3762 * HOL/typedef: fixed type inference for representing set; type
  3763 arguments now have to occur explicitly on the rhs as type constraints;
  3764 
  3765 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3766 names rather than an ML expression;
  3767 
  3768 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3769 supplied later.  Program schemes can be defined, such as
  3770     "While B C s = (if B s then While B C (C s) else s)"
  3771 where the well-founded relation can be chosen after B and C have been given.
  3772 
  3773 * HOL/List: the constructors of type list are now Nil and Cons;
  3774 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3775 course, ML tools referring to List.list.op # etc. have to be adapted;
  3776 
  3777 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3778 disabled by default; run isabelle with option -m HOL to get back to
  3779 the original Gordon/HOL-style output;
  3780 
  3781 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3782 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3783 
  3784 * HOL basic syntax simplified (more orthogonal): all variants of
  3785 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3786 Eps operator is provided as well: "SOME x. P[x]";
  3787 
  3788 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3789 
  3790 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3791 thus available for user theories;
  3792 
  3793 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3794 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3795 time;
  3796 
  3797 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3798 several times and then mp;
  3799 
  3800 
  3801 *** LK ***
  3802 
  3803 * the notation <<...>> is now available as a notation for sequences of
  3804 formulas;
  3805 
  3806 * the simplifier is now installed
  3807 
  3808 * the axiom system has been generalized (thanks to Soren Heilmann)
  3809 
  3810 * the classical reasoner now has a default rule database
  3811 
  3812 
  3813 *** ZF ***
  3814 
  3815 * new primrec section allows primitive recursive functions to be given
  3816 directly (as in HOL) over datatypes and the natural numbers;
  3817 
  3818 * new tactics induct_tac and exhaust_tac for induction (or case
  3819 analysis) over datatypes and the natural numbers;
  3820 
  3821 * the datatype declaration of type T now defines the recursor T_rec;
  3822 
  3823 * simplification automatically does freeness reasoning for datatype
  3824 constructors;
  3825 
  3826 * automatic type-inference, with AddTCs command to insert new
  3827 type-checking rules;
  3828 
  3829 * datatype introduction rules are now added as Safe Introduction rules
  3830 to the claset;
  3831 
  3832 * the syntax "if P then x else y" is now available in addition to
  3833 if(P,x,y);
  3834 
  3835 
  3836 *** Internal programming interfaces ***
  3837 
  3838 * tuned simplifier trace output; new flag debug_simp;
  3839 
  3840 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3841 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3842 
  3843 * AxClass.axclass_tac lost the theory argument;
  3844 
  3845 * tuned current_goals_markers semantics: begin / end goal avoids
  3846 printing empty lines;
  3847 
  3848 * removed prs and prs_fn hook, which was broken because it did not
  3849 include \n in its semantics, forcing writeln to add one
  3850 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3851 string -> unit if you really want to output text without newline;
  3852 
  3853 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3854 plain output, interface builders may have to enable 'isabelle_font'
  3855 mode to get Isabelle font glyphs as before;
  3856 
  3857 * refined token_translation interface; INCOMPATIBILITY: output length
  3858 now of type real instead of int;
  3859 
  3860 * theory loader actions may be traced via new ThyInfo.add_hook
  3861 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3862 your own database of information attached to *whole* theories -- as
  3863 opposed to intra-theory data slots offered via TheoryDataFun;
  3864 
  3865 * proper handling of dangling sort hypotheses (at last!);
  3866 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3867 extra sort hypotheses that can be witnessed from the type signature;
  3868 the force_strip_shyps flag is gone, any remaining shyps are simply
  3869 left in the theorem (with a warning issued by strip_shyps_warning);
  3870 
  3871 
  3872 
  3873 New in Isabelle98-1 (October 1998)
  3874 ----------------------------------
  3875 
  3876 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3877 
  3878 * several changes of automated proof tools;
  3879 
  3880 * HOL: major changes to the inductive and datatype packages, including
  3881 some minor incompatibilities of theory syntax;
  3882 
  3883 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3884 called `inj_on';
  3885 
  3886 * HOL: removed duplicate thms in Arith:
  3887   less_imp_add_less  should be replaced by  trans_less_add1
  3888   le_imp_add_le      should be replaced by  trans_le_add1
  3889 
  3890 * HOL: unary minus is now overloaded (new type constraints may be
  3891 required);
  3892 
  3893 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3894 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3895 now taken as an integer constant.
  3896 
  3897 * Pure: ML function 'theory_of' renamed to 'theory';
  3898 
  3899 
  3900 *** Proof tools ***
  3901 
  3902 * Simplifier:
  3903   1. Asm_full_simp_tac is now more aggressive.
  3904      1. It will sometimes reorient premises if that increases their power to
  3905         simplify.
  3906      2. It does no longer proceed strictly from left to right but may also
  3907         rotate premises to achieve further simplification.
  3908      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3909      old Asm_full_simp_tac in that it does not rotate premises.
  3910   2. The simplifier now knows a little bit about nat-arithmetic.
  3911 
  3912 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3913 allows for selected deletion of wrappers, by introduction of names for
  3914 wrapper functionals.  This implies that addbefore, addSbefore,
  3915 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3916 and that adding two tactics with the same name overwrites the first
  3917 one (emitting a warning).
  3918   type wrapper = (int -> tactic) -> (int -> tactic)
  3919   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3920   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3921   delWrapper, delSWrapper: claset *  string            -> claset
  3922   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3923 
  3924 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3925 semantics; addbefore now affects only the unsafe part of step_tac
  3926 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3927 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3928 by Force_tac;
  3929 
  3930 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3931 compWrapper; added safe wrapper (and access functions for it);
  3932 
  3933 * HOL/split_all_tac is now much faster and fails if there is nothing
  3934 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3935 and the names of the automatically generated variables have changed.
  3936 split_all_tac has moved within claset() from unsafe wrappers to safe
  3937 wrappers, which means that !!-bound variables are split much more
  3938 aggressively, and safe_tac and clarify_tac now split such variables.
  3939 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3940 Note: the same holds for record_split_tac, which does the job of
  3941 split_all_tac for record fields.
  3942 
  3943 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3944 permanently to the default simpset using Addsplits just like
  3945 Addsimps. They can be removed via Delsplits just like
  3946 Delsimps. Lower-case versions are also available.
  3947 
  3948 * HOL/Simplifier: The rule split_if is now part of the default
  3949 simpset. This means that the simplifier will eliminate all occurrences
  3950 of if-then-else in the conclusion of a goal. To prevent this, you can
  3951 either remove split_if completely from the default simpset by
  3952 `Delsplits [split_if]' or remove it in a specific call of the
  3953 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3954 other case splitting rules to/from the default simpset: every datatype
  3955 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3956 t is the name of the datatype).
  3957 
  3958 * Classical reasoner / Simplifier combination: new force_tac (and
  3959 derivatives Force_tac, force) combines rewriting and classical
  3960 reasoning (and whatever other tools) similarly to auto_tac, but is
  3961 aimed to solve the given subgoal completely.
  3962 
  3963 
  3964 *** General ***
  3965 
  3966 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3967 and `goalw': the theory is no longer needed as an explicit argument -
  3968 the current theory context is used; assumptions are no longer returned
  3969 at the ML-level unless one of them starts with ==> or !!; it is
  3970 recommended to convert to these new commands using isatool fixgoal
  3971 (backup your sources first!);
  3972 
  3973 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3974 the current theory context, and 'theory' to lookup stored theories;
  3975 
  3976 * new theory section 'locale' for declaring constants, assumptions and
  3977 definitions that have local scope;
  3978 
  3979 * new theory section 'nonterminals' for purely syntactic types;
  3980 
  3981 * new theory section 'setup' for generic ML setup functions
  3982 (e.g. package initialization);
  3983 
  3984 * the distribution now includes Isabelle icons: see
  3985 lib/logo/isabelle-{small,tiny}.xpm;
  3986 
  3987 * isatool install - install binaries with absolute references to
  3988 ISABELLE_HOME/bin;
  3989 
  3990 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3991 
  3992 * print mode 'emacs' reserved for Isamode;
  3993 
  3994 * support multiple print (ast) translations per constant name;
  3995 
  3996 * theorems involving oracles are now printed with a suffixed [!];
  3997 
  3998 
  3999 *** HOL ***
  4000 
  4001 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4002 
  4003 * HOL/inductive package reorganized and improved: now supports mutual
  4004 definitions such as
  4005 
  4006   inductive EVEN ODD
  4007     intrs
  4008       null "0 : EVEN"
  4009       oddI "n : EVEN ==> Suc n : ODD"
  4010       evenI "n : ODD ==> Suc n : EVEN"
  4011 
  4012 new theorem list "elims" contains an elimination rule for each of the
  4013 recursive sets; inductive definitions now handle disjunctive premises
  4014 correctly (also ZF);
  4015 
  4016 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4017 "mutual_induct" no longer exists - the induction rule is always
  4018 contained in "induct";
  4019 
  4020 
  4021 * HOL/datatype package re-implemented and greatly improved: now
  4022 supports mutually recursive datatypes such as
  4023 
  4024   datatype
  4025     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4026             | SUM ('a aexp) ('a aexp)
  4027             | DIFF ('a aexp) ('a aexp)
  4028             | NUM 'a
  4029   and
  4030     'a bexp = LESS ('a aexp) ('a aexp)
  4031             | AND ('a bexp) ('a bexp)
  4032             | OR ('a bexp) ('a bexp)
  4033 
  4034 as well as indirectly recursive datatypes such as
  4035 
  4036   datatype
  4037     ('a, 'b) term = Var 'a
  4038                   | App 'b ((('a, 'b) term) list)
  4039 
  4040 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4041 induction on mutually / indirectly recursive datatypes.
  4042 
  4043 Primrec equations are now stored in theory and can be accessed via
  4044 <function_name>.simps.
  4045 
  4046 INCOMPATIBILITIES:
  4047 
  4048   - Theories using datatypes must now have theory Datatype as an
  4049     ancestor.
  4050   - The specific <typename>.induct_tac no longer exists - use the
  4051     generic induct_tac instead.
  4052   - natE has been renamed to nat.exhaust - use exhaust_tac
  4053     instead of res_inst_tac ... natE. Note that the variable
  4054     names in nat.exhaust differ from the names in natE, this
  4055     may cause some "fragile" proofs to fail.
  4056   - The theorems split_<typename>_case and split_<typename>_case_asm
  4057     have been renamed to <typename>.split and <typename>.split_asm.
  4058   - Since default sorts of type variables are now handled correctly,
  4059     some datatype definitions may have to be annotated with explicit
  4060     sort constraints.
  4061   - Primrec definitions no longer require function name and type
  4062     of recursive argument.
  4063 
  4064 Consider using isatool fixdatatype to adapt your theories and proof
  4065 scripts to the new package (backup your sources first!).
  4066 
  4067 
  4068 * HOL/record package: considerably improved implementation; now
  4069 includes concrete syntax for record types, terms, updates; theorems
  4070 for surjective pairing and splitting !!-bound record variables; proof
  4071 support is as follows:
  4072 
  4073   1) standard conversions (selectors or updates applied to record
  4074 constructor terms) are part of the standard simpset;
  4075 
  4076   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4077 made part of standard simpset and claset via addIffs;
  4078 
  4079   3) a tactic for record field splitting (record_split_tac) is part of
  4080 the standard claset (addSWrapper);
  4081 
  4082 To get a better idea about these rules you may retrieve them via
  4083 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4084 the name of your record type.
  4085 
  4086 The split tactic 3) conceptually simplifies by the following rule:
  4087 
  4088   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4089 
  4090 Thus any record variable that is bound by meta-all will automatically
  4091 blow up into some record constructor term, consequently the
  4092 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4093 solve record problems automatically.
  4094 
  4095 
  4096 * reorganized the main HOL image: HOL/Integ and String loaded by
  4097 default; theory Main includes everything;
  4098 
  4099 * automatic simplification of integer sums and comparisons, using cancellation;
  4100 
  4101 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4102 
  4103 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4104 
  4105 * many new identities for unions, intersections, set difference, etc.;
  4106 
  4107 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4108 called split_if, split_split, split_sum_case and split_nat_case (to go
  4109 with add/delsplits);
  4110 
  4111 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4112 (?x::unit) = (); this is made part of the default simpset, which COULD
  4113 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4114 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4115 unit_abs_eta_conv is added in order to counter the effect of
  4116 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4117 %u.f();
  4118 
  4119 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4120 makes more sense);
  4121 
  4122 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4123   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4124   disjointness reasoning but breaking a few old proofs.
  4125 
  4126 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4127 to 'converse' from 'inverse' (for compatibility with ZF and some
  4128 literature);
  4129 
  4130 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4131 the well-founded relation;
  4132 
  4133 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4134     Compl A.  The "Compl" syntax remains available as input syntax for this
  4135     release ONLY.
  4136 
  4137 * HOL/Update: new theory of function updates:
  4138     f(a:=b) == %x. if x=a then b else f x
  4139 may also be iterated as in f(a:=b,c:=d,...);
  4140 
  4141 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4142 
  4143 * HOL/List:
  4144   - new function list_update written xs[i:=v] that updates the i-th
  4145     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4146   - new function `upt' written [i..j(] which generates the list
  4147     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4148     bound write [i..j], which is a shorthand for [i..j+1(].
  4149   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4150 
  4151 * HOL/Arith:
  4152   - removed 'pred' (predecessor) function;
  4153   - generalized some theorems about n-1;
  4154   - many new laws about "div" and "mod";
  4155   - new laws about greatest common divisors (see theory ex/Primes);
  4156 
  4157 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4158 instead of "inverse";
  4159 
  4160 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4161   of the multiset ordering;
  4162 
  4163 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4164   (not included by default);
  4165 
  4166 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4167 
  4168 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4169   programs, i.e. different program variables may have different types.
  4170 
  4171 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4172   [previously, this check worked only if the rewrite rule was unconditional]
  4173   Now rew can involve either definitions or equalities (either == or =).
  4174 
  4175 
  4176 *** ZF ***
  4177 
  4178 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4179   only the theorems proved on ZF.ML;
  4180 
  4181 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4182   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4183   disjointness reasoning but breaking a few old proofs.
  4184 
  4185 * ZF/Update: new theory of function updates
  4186     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4187   may also be iterated as in f(a:=b,c:=d,...);
  4188 
  4189 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4190 
  4191 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4192   [previously, this check worked only if the rewrite rule was unconditional]
  4193   Now rew can involve either definitions or equalities (either == or =).
  4194 
  4195 * case_tac provided for compatibility with HOL
  4196     (like the old excluded_middle_tac, but with subgoals swapped)
  4197 
  4198 
  4199 *** Internal programming interfaces ***
  4200 
  4201 * Pure: several new basic modules made available for general use, see
  4202 also src/Pure/README;
  4203 
  4204 * improved the theory data mechanism to support encapsulation (data
  4205 kind name replaced by private Object.kind, acting as authorization
  4206 key); new type-safe user interface via functor TheoryDataFun; generic
  4207 print_data function becomes basically useless;
  4208 
  4209 * removed global_names compatibility flag -- all theory declarations
  4210 are qualified by default;
  4211 
  4212 * module Pure/Syntax now offers quote / antiquote translation
  4213 functions (useful for Hoare logic etc. with implicit dependencies);
  4214 see HOL/ex/Antiquote for an example use;
  4215 
  4216 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4217 cterm -> thm;
  4218 
  4219 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4220 subgoal;
  4221 
  4222 * Display.print_goals function moved to Locale.print_goals;
  4223 
  4224 * standard print function for goals supports current_goals_markers
  4225 variable for marking begin of proof, end of proof, start of goal; the
  4226 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4227 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4228 for example;
  4229 
  4230 
  4231 
  4232 New in Isabelle98 (January 1998)
  4233 --------------------------------
  4234 
  4235 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4236 
  4237 * changed lexical syntax of terms / types: dots made part of long
  4238 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4239 
  4240 * simpset (and claset) reference variable replaced by functions
  4241 simpset / simpset_ref;
  4242 
  4243 * no longer supports theory aliases (via merge) and non-trivial
  4244 implicit merge of thms' signatures;
  4245 
  4246 * most internal names of constants changed due to qualified names;
  4247 
  4248 * changed Pure/Sequence interface (see Pure/seq.ML);
  4249 
  4250 
  4251 *** General Changes ***
  4252 
  4253 * hierachically structured name spaces (for consts, types, axms, thms
  4254 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4255 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4256 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4257 long_names for fully qualified output names; NOTE: ML programs
  4258 (special tactics, packages etc.) referring to internal names may have
  4259 to be adapted to cope with fully qualified names; in case of severe
  4260 backward campatibility problems try setting 'global_names' at compile
  4261 time to have enrything declared within a flat name space; one may also
  4262 fine tune name declarations in theories via the 'global' and 'local'
  4263 section;
  4264 
  4265 * reimplemented the implicit simpset and claset using the new anytype
  4266 data filed in signatures; references simpset:simpset ref etc. are
  4267 replaced by functions simpset:unit->simpset and
  4268 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4269 to patch your ML files accordingly;
  4270 
  4271 * HTML output now includes theory graph data for display with Java
  4272 applet or isatool browser; data generated automatically via isatool
  4273 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4274 
  4275 * defs may now be conditional; improved rewrite_goals_tac to handle
  4276 conditional equations;
  4277 
  4278 * defs now admits additional type arguments, using TYPE('a) syntax;
  4279 
  4280 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4281 creates a new theory node; implicit merge of thms' signatures is
  4282 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4283 transfer:theory->thm->thm in (rare) cases;
  4284 
  4285 * improved handling of draft signatures / theories; draft thms (and
  4286 ctyps, cterms) are automatically promoted to real ones;
  4287 
  4288 * slightly changed interfaces for oracles: admit many per theory, named
  4289 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4290 
  4291 * print_goals: optional output of const types (set show_consts and
  4292 show_types);
  4293 
  4294 * improved output of warnings (###) and errors (***);
  4295 
  4296 * subgoal_tac displays a warning if the new subgoal has type variables;
  4297 
  4298 * removed old README and Makefiles;
  4299 
  4300 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4301 
  4302 * removed obsolete init_pps and init_database;
  4303 
  4304 * deleted the obsolete tactical STATE, which was declared by
  4305     fun STATE tacfun st = tacfun st st;
  4306 
  4307 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4308 (which abbreviates $HOME);
  4309 
  4310 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4311 use isatool fixseq to adapt your ML programs (this works for fully
  4312 qualified references to the Sequence structure only!);
  4313 
  4314 * use_thy no longer requires writable current directory; it always
  4315 reloads .ML *and* .thy file, if either one is out of date;
  4316 
  4317 
  4318 *** Classical Reasoner ***
  4319 
  4320 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4321 tactics that use classical reasoning to simplify a subgoal without
  4322 splitting it into several subgoals;
  4323 
  4324 * Safe_tac: like safe_tac but uses the default claset;
  4325 
  4326 
  4327 *** Simplifier ***
  4328 
  4329 * added simplification meta rules:
  4330     (asm_)(full_)simplify: simpset -> thm -> thm;
  4331 
  4332 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4333 logics (again);
  4334 
  4335 * added prems argument to simplification procedures;
  4336 
  4337 * HOL, FOL, ZF: added infix function `addsplits':
  4338   instead of `<simpset> setloop (split_tac <thms>)'
  4339   you can simply write `<simpset> addsplits <thms>'
  4340 
  4341 
  4342 *** Syntax ***
  4343 
  4344 * TYPE('a) syntax for type reflection terms;
  4345 
  4346 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4347 
  4348 * pretty printer: changed order of mixfix annotation preference (again!);
  4349 
  4350 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4351 
  4352 
  4353 *** HOL ***
  4354 
  4355 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4356   with `addloop' of the simplifier to faciliate case splitting in premises.
  4357 
  4358 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4359 
  4360 * HOL/Auth: new protocol proofs including some for the Internet
  4361   protocol TLS;
  4362 
  4363 * HOL/Map: new theory of `maps' a la VDM;
  4364 
  4365 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4366 cancelling out common nat summands from =, <, <= (in)equalities, or
  4367 differences; simplification procedures nat_cancel_factor for
  4368 cancelling common factor from =, <, <= (in)equalities over natural
  4369 sums; nat_cancel contains both kinds of procedures, it is installed by
  4370 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4371 
  4372 * HOL/simplifier: terms of the form
  4373   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4374   are rewritten to
  4375   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4376   and those of the form
  4377   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4378   are rewritten to
  4379   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4380 
  4381 * HOL/datatype
  4382   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4383 
  4384   P(t_case f1 ... fn x) =
  4385      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4386         ...
  4387        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4388      )
  4389 
  4390   and a theorem `split_t_case_asm' of the form
  4391 
  4392   P(t_case f1 ... fn x) =
  4393     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4394         ...
  4395        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4396      )
  4397   which can be added to a simpset via `addsplits'. The existing theorems
  4398   expand_list_case and expand_option_case have been renamed to
  4399   split_list_case and split_option_case.
  4400 
  4401 * HOL/Arithmetic:
  4402   - `pred n' is automatically converted to `n-1'.
  4403     Users are strongly encouraged not to use `pred' any longer,
  4404     because it will disappear altogether at some point.
  4405   - Users are strongly encouraged to write "0 < n" rather than
  4406     "n ~= 0". Theorems and proof tools have been modified towards this
  4407     `standard'.
  4408 
  4409 * HOL/Lists:
  4410   the function "set_of_list" has been renamed "set" (and its theorems too);
  4411   the function "nth" now takes its arguments in the reverse order and
  4412   has acquired the infix notation "!" as in "xs!n".
  4413 
  4414 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4415 
  4416 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4417   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4418 
  4419 * HOL/record: extensible records with schematic structural subtyping
  4420 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4421 still lacks various theorems and concrete record syntax;
  4422 
  4423 
  4424 *** HOLCF ***
  4425 
  4426 * removed "axioms" and "generated by" sections;
  4427 
  4428 * replaced "ops" section by extended "consts" section, which is capable of
  4429   handling the continuous function space "->" directly;
  4430 
  4431 * domain package:
  4432   . proves theorems immediately and stores them in the theory,
  4433   . creates hierachical name space,
  4434   . now uses normal mixfix annotations (instead of cinfix...),
  4435   . minor changes to some names and values (for consistency),
  4436   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4437   . separator between mutual domain defs: changed "," to "and",
  4438   . improved handling of sort constraints;  now they have to
  4439     appear on the left-hand side of the equations only;
  4440 
  4441 * fixed LAM <x,y,zs>.b syntax;
  4442 
  4443 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4444 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4445 
  4446 
  4447 *** FOL and ZF ***
  4448 
  4449 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4450   with `addloop' of the simplifier to faciliate case splitting in premises.
  4451 
  4452 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4453 in HOL, they strip ALL and --> from proved theorems;
  4454 
  4455 
  4456 
  4457 New in Isabelle94-8 (May 1997)
  4458 ------------------------------
  4459 
  4460 *** General Changes ***
  4461 
  4462 * new utilities to build / run / maintain Isabelle etc. (in parts
  4463 still somewhat experimental); old Makefiles etc. still functional;
  4464 
  4465 * new 'Isabelle System Manual';
  4466 
  4467 * INSTALL text, together with ./configure and ./build scripts;
  4468 
  4469 * reimplemented type inference for greater efficiency, better error
  4470 messages and clean internal interface;
  4471 
  4472 * prlim command for dealing with lots of subgoals (an easier way of
  4473 setting goals_limit);
  4474 
  4475 
  4476 *** Syntax ***
  4477 
  4478 * supports alternative (named) syntax tables (parser and pretty
  4479 printer); internal interface is provided by add_modesyntax(_i);
  4480 
  4481 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4482 be used in conjunction with the Isabelle symbol font; uses the
  4483 "symbols" syntax table;
  4484 
  4485 * added token_translation interface (may translate name tokens in
  4486 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4487 the current print_mode); IMPORTANT: user print translation functions
  4488 are responsible for marking newly introduced bounds
  4489 (Syntax.mark_boundT);
  4490 
  4491 * token translations for modes "xterm" and "xterm_color" that display
  4492 names in bold, underline etc. or colors (which requires a color
  4493 version of xterm);
  4494 
  4495 * infixes may now be declared with names independent of their syntax;
  4496 
  4497 * added typed_print_translation (like print_translation, but may
  4498 access type of constant);
  4499 
  4500 
  4501 *** Classical Reasoner ***
  4502 
  4503 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4504 some limitations.  Blast_tac...
  4505   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4506   + ignores elimination rules that don't have the correct format
  4507         (the conclusion MUST be a formula variable)
  4508   + ignores types, which can make HOL proofs fail
  4509   + rules must not require higher-order unification, e.g. apply_type in ZF
  4510     [message "Function Var's argument not a bound variable" relates to this]
  4511   + its proof strategy is more general but can actually be slower
  4512 
  4513 * substitution with equality assumptions no longer permutes other
  4514 assumptions;
  4515 
  4516 * minor changes in semantics of addafter (now called addaltern); renamed
  4517 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4518 (and access functions for it);
  4519 
  4520 * improved combination of classical reasoner and simplifier:
  4521   + functions for handling clasimpsets
  4522   + improvement of addss: now the simplifier is called _after_ the
  4523     safe steps.
  4524   + safe variant of addss called addSss: uses safe simplifications
  4525     _during_ the safe steps. It is more complete as it allows multiple
  4526     instantiations of unknowns (e.g. with slow_tac).
  4527 
  4528 *** Simplifier ***
  4529 
  4530 * added interface for simplification procedures (functions that
  4531 produce *proven* rewrite rules on the fly, depending on current
  4532 redex);
  4533 
  4534 * ordering on terms as parameter (used for ordered rewriting);
  4535 
  4536 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4537 
  4538 * the solver is now split into a safe and an unsafe part.
  4539 This should be invisible for the normal user, except that the
  4540 functions setsolver and addsolver have been renamed to setSolver and
  4541 addSolver; added safe_asm_full_simp_tac;
  4542 
  4543 
  4544 *** HOL ***
  4545 
  4546 * a generic induction tactic `induct_tac' which works for all datatypes and
  4547 also for type `nat';
  4548 
  4549 * a generic case distinction tactic `exhaust_tac' which works for all
  4550 datatypes and also for type `nat';
  4551 
  4552 * each datatype comes with a function `size';
  4553 
  4554 * patterns in case expressions allow tuple patterns as arguments to
  4555 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4556 
  4557 * primrec now also works with type nat;
  4558 
  4559 * recdef: a new declaration form, allows general recursive functions to be
  4560 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4561 
  4562 * the constant for negation has been renamed from "not" to "Not" to
  4563 harmonize with FOL, ZF, LK, etc.;
  4564 
  4565 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4566 infinite lists;
  4567 
  4568 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4569 
  4570 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4571 problems in commutative rings, using axiomatic type classes for + and *;
  4572 
  4573 * more examples in HOL/MiniML and HOL/Auth;
  4574 
  4575 * more default rewrite rules for quantifiers, union/intersection;
  4576 
  4577 * a new constant `arbitrary == @x.False';
  4578 
  4579 * HOLCF/IOA replaces old HOL/IOA;
  4580 
  4581 * HOLCF changes: derived all rules and arities
  4582   + axiomatic type classes instead of classes
  4583   + typedef instead of faking type definitions
  4584   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4585   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4586   + eliminated the types void, one, tr
  4587   + use unit lift and bool lift (with translations) instead of one and tr
  4588   + eliminated blift from Lift3.thy (use Def instead of blift)
  4589   all eliminated rules are derived as theorems --> no visible changes ;
  4590 
  4591 
  4592 *** ZF ***
  4593 
  4594 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4595 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4596 as ZF_cs addSIs [equalityI];
  4597 
  4598 
  4599 
  4600 New in Isabelle94-7 (November 96)
  4601 ---------------------------------
  4602 
  4603 * allowing negative levels (as offsets) in prlev and choplev;
  4604 
  4605 * super-linear speedup for large simplifications;
  4606 
  4607 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4608 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4609 FAIL); can suppress it using the command Delsimps (ex_simps @
  4610 all_simps); De Morgan laws are also now included, by default;
  4611 
  4612 * improved printing of ==>  :  ~:
  4613 
  4614 * new object-logic "Sequents" adds linear logic, while replacing LK
  4615 and Modal (thanks to Sara Kalvala);
  4616 
  4617 * HOL/Auth: correctness proofs for authentication protocols;
  4618 
  4619 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4620 examples on HOL/Auth);
  4621 
  4622 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4623 the rewriter and classical reasoner simultaneously;
  4624 
  4625 * function uresult no longer returns theorems in "standard" format;
  4626 regain previous version by: val uresult = standard o uresult;
  4627 
  4628 
  4629 
  4630 New in Isabelle94-6
  4631 -------------------
  4632 
  4633 * oracles -- these establish an interface between Isabelle and trusted
  4634 external reasoners, which may deliver results as theorems;
  4635 
  4636 * proof objects (in particular record all uses of oracles);
  4637 
  4638 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4639 
  4640 * "constdefs" section in theory files;
  4641 
  4642 * "primrec" section (HOL) no longer requires names;
  4643 
  4644 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4645 
  4646 
  4647 
  4648 New in Isabelle94-5
  4649 -------------------
  4650 
  4651 * reduced space requirements;
  4652 
  4653 * automatic HTML generation from theories;
  4654 
  4655 * theory files no longer require "..." (quotes) around most types;
  4656 
  4657 * new examples, including two proofs of the Church-Rosser theorem;
  4658 
  4659 * non-curried (1994) version of HOL is no longer distributed;
  4660 
  4661 
  4662 
  4663 New in Isabelle94-4
  4664 -------------------
  4665 
  4666 * greatly reduced space requirements;
  4667 
  4668 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4669 
  4670 * searchable theorem database (see the section "Retrieving theorems" on
  4671 page 8 of the Reference Manual);
  4672 
  4673 * new examples, including Grabczewski's monumental case study of the
  4674 Axiom of Choice;
  4675 
  4676 * The previous version of HOL renamed to Old_HOL;
  4677 
  4678 * The new version of HOL (previously called CHOL) uses a curried syntax
  4679 for functions.  Application looks like f a b instead of f(a,b);
  4680 
  4681 * Mutually recursive inductive definitions finally work in HOL;
  4682 
  4683 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4684 translates to the operator "split";
  4685 
  4686 
  4687 
  4688 New in Isabelle94-3
  4689 -------------------
  4690 
  4691 * new infix operator, addss, allowing the classical reasoner to
  4692 perform simplification at each step of its search.  Example:
  4693         fast_tac (cs addss ss)
  4694 
  4695 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4696 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4697 look like (a,b) instead of <a,b>;
  4698 
  4699 * PLEASE NOTE: CHOL will eventually replace HOL!
  4700 
  4701 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4702 It translates to the operator "split".  A new theory of integers is available;
  4703 
  4704 * In ZF, integer numerals now denote two's-complement binary integers.
  4705 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4706 
  4707 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4708 of the Axiom of Choice;
  4709 
  4710 
  4711 
  4712 New in Isabelle94-2
  4713 -------------------
  4714 
  4715 * Significantly faster resolution;
  4716 
  4717 * the different sections in a .thy file can now be mixed and repeated
  4718 freely;
  4719 
  4720 * Database of theorems for FOL, HOL and ZF.  New
  4721 commands including qed, qed_goal and bind_thm store theorems in the database.
  4722 
  4723 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4724 a given theory (thms_of), or find out what theory a theorem was proved in
  4725 (theory_of_thm);
  4726 
  4727 * Bugs fixed in the inductive definition and datatype packages;
  4728 
  4729 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4730 and HOL_dup_cs obsolete;
  4731 
  4732 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4733 have been removed;
  4734 
  4735 * Simpler definition of function space in ZF;
  4736 
  4737 * new results about cardinal and ordinal arithmetic in ZF;
  4738 
  4739 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4740 types;
  4741 
  4742 
  4743 $Id$