NEWS
author haftmann
Thu May 10 22:11:38 2007 +0200 (2007-05-10)
changeset 22930 f99617e7103f
parent 22921 475ff421a6a3
child 22965 b81bbe298406
permissions -rw-r--r--
(class target)
     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 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    37 by default, which means that "prems" (and also "fixed variables") are
    38 suppressed from proof state output.  Note that the ProofGeneral
    39 settings mechanism allows to change and save options persistently, but
    40 older versions of Isabelle will fail to start up if a negative prems
    41 limit is imposed.
    42 
    43 * Local theory targets may be specified by non-nested blocks of
    44 ``context/locale/class ... begin'' followed by ``end''.  The body may
    45 contain definitions, theorems etc., including any derived mechanism
    46 that has been implemented on top of these primitives.  This concept
    47 generalizes the existing ``theorem (in ...)'' towards more versatility
    48 and scalability.
    49 
    50 * Proof General interface: proper undo of final 'end' command;
    51 discontinued Isabelle/classic mode (ML proof scripts).
    52 
    53 
    54 *** Document preparation ***
    55 
    56 * Added antiquotation @{theory name} which prints the given name,
    57 after checking that it refers to a valid ancestor theory in the
    58 current context.
    59 
    60 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    61 check the given source text as ML type/structure, printing verbatim.
    62 
    63 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    64 "c args == rhs" given in the current context.  (Any number of
    65 arguments may be given on the LHS.)
    66 
    67 
    68 
    69 *** Pure ***
    70 
    71 * code generator: consts in 'consts_code' Isar commands are now referred
    72   to by usual term syntax (including optional type annotations).
    73 
    74 * code generator: 
    75   - Isar 'definition's, 'constdef's and primitive instance definitions are added
    76     explicitly to the table of defining equations
    77   - primitive definitions are not used as defining equations by default any longer
    78   - defining equations are now definitly restricted to meta "==" and object
    79         equality "="
    80   - HOL theories have been adopted accordingly
    81 
    82 * class_package.ML offers a combination of axclasses and locales to
    83 achieve Haskell-like type classes in Isabelle.  See
    84 HOL/ex/Classpackage.thy for examples.
    85 
    86 * Yet another code generator framework allows to generate executable
    87 code for ML and Haskell (including "class"es).  A short usage sketch:
    88 
    89     internal compilation:
    90         code_gen <list of constants (term syntax)> (SML #)
    91     writing SML code to a file:
    92         code_gen <list of constants (term syntax)> (SML <filename>)
    93     writing OCaml code to a file:
    94         code_gen <list of constants (term syntax)> (OCaml <filename>)
    95     writing Haskell code to a bunch of files:
    96         code_gen <list of constants (term syntax)> (Haskell <filename>)
    97 
    98 Reasonable default setup of framework in HOL/Main.
    99 
   100 Theorem attributs for selecting and transforming function equations theorems:
   101 
   102     [code fun]:        select a theorem as function equation for a specific constant
   103     [code fun del]:    deselect a theorem as function equation for a specific constant
   104     [code inline]:     select an equation theorem for unfolding (inlining) in place
   105     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   106 
   107 User-defined serializations (target in {SML, OCaml, Haskell}):
   108 
   109     code_const <and-list of constants (term syntax)>
   110       {(target) <and-list of const target syntax>}+
   111 
   112     code_type <and-list of type constructors>
   113       {(target) <and-list of type target syntax>}+
   114 
   115     code_instance <and-list of instances>
   116       {(target)}+
   117         where instance ::= <type constructor> :: <class>
   118 
   119     code_class <and_list of classes>
   120       {(target) <and-list of class target syntax>}+
   121         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   122 
   123 code_instance and code_class only apply to target Haskell.
   124 
   125 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   126 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   127 
   128 * Command 'no_translations' removes translation rules from theory
   129 syntax.
   130 
   131 * Overloaded definitions are now actually checked for acyclic
   132 dependencies.  The overloading scheme is slightly more general than
   133 that of Haskell98, although Isabelle does not demand an exact
   134 correspondence to type class and instance declarations.
   135 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   136 exotic versions of overloading -- at the discretion of the user!
   137 
   138 Polymorphic constants are represented via type arguments, i.e. the
   139 instantiation that matches an instance against the most general
   140 declaration given in the signature.  For example, with the declaration
   141 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   142 as c(nat).  Overloading is essentially simultaneous structural
   143 recursion over such type arguments.  Incomplete specification patterns
   144 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   145 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   146 Command 'print_theory' outputs the normalized system of recursive
   147 equations, see section "definitions".
   148 
   149 * Isar: improper proof element 'guess' is like 'obtain', but derives
   150 the obtained context from the course of reasoning!  For example:
   151 
   152   assume "EX x y. A x & B y"   -- "any previous fact"
   153   then guess x and y by clarify
   154 
   155 This technique is potentially adventurous, depending on the facts and
   156 proof tools being involved here.
   157 
   158 * Isar: known facts from the proof context may be specified as literal
   159 propositions, using ASCII back-quote syntax.  This works wherever
   160 named facts used to be allowed so far, in proof commands, proof
   161 methods, attributes etc.  Literal facts are retrieved from the context
   162 according to unification of type and term parameters.  For example,
   163 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   164 theorems in the current context, then these are valid literal facts:
   165 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   166 
   167 There is also a proof method "fact" which does the same composition
   168 for explicit goal states, e.g. the following proof texts coincide with
   169 certain special cases of literal facts:
   170 
   171   have "A" by fact                 ==  note `A`
   172   have "A ==> B" by fact           ==  note `A ==> B`
   173   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   174   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   175 
   176 * Isar: ":" (colon) is no longer a symbolic identifier character in
   177 outer syntax.  Thus symbolic identifiers may be used without
   178 additional white space in declarations like this: ``assume *: A''.
   179 
   180 * Isar: 'print_facts' prints all local facts of the current context,
   181 both named and unnamed ones.
   182 
   183 * Isar: 'def' now admits simultaneous definitions, e.g.:
   184 
   185   def x == "t" and y == "u"
   186 
   187 * Isar: added command 'unfolding', which is structurally similar to
   188 'using', but affects both the goal state and facts by unfolding given
   189 rewrite rules.  Thus many occurrences of the 'unfold' method or
   190 'unfolded' attribute may be replaced by first-class proof text.
   191 
   192 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   193 and command 'unfolding' now all support object-level equalities
   194 (potentially conditional).  The underlying notion of rewrite rule is
   195 analogous to the 'rule_format' attribute, but *not* that of the
   196 Simplifier (which is usually more generous).
   197 
   198 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   199 method expression within a sandbox consisting of the first N
   200 sub-goals, which need to exist.  For example, ``simp_all [3]''
   201 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   202 simplifies all new goals that emerge from applying rule foo to the
   203 originally first one.
   204 
   205 * Isar: schematic goals are no longer restricted to higher-order
   206 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   207 expected.
   208 
   209 * Isar: the conclusion of a long theorem statement is now either
   210 'shows' (a simultaneous conjunction, as before), or 'obtains'
   211 (essentially a disjunction of cases with local parameters and
   212 assumptions).  The latter allows to express general elimination rules
   213 adequately; in this notation common elimination rules look like this:
   214 
   215   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   216     assumes "EX x. P x"
   217     obtains x where "P x"
   218 
   219   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   220     assumes "A & B"
   221     obtains A and B
   222 
   223   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   224     assumes "A | B"
   225     obtains
   226       A
   227     | B
   228 
   229 The subsequent classical rules even refer to the formal "thesis"
   230 explicitly:
   231 
   232   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   233     obtains "~ thesis"
   234 
   235   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   236     obtains "thesis ==> something"
   237 
   238 The actual proof of an 'obtains' statement is analogous to that of the
   239 Isar proof element 'obtain', only that there may be several cases.
   240 Optional case names may be specified in parentheses; these will be
   241 available both in the present proof and as annotations in the
   242 resulting rule, for later use with the 'cases' method (cf. attribute
   243 case_names).
   244 
   245 * Isar: the assumptions of a long theorem statement are available as
   246 "assms" fact in the proof context.  This is more appropriate than the
   247 (historical) "prems", which refers to all assumptions of the current
   248 context, including those from the target locale, proof body etc.
   249 
   250 * Isar: 'print_statement' prints theorems from the current theory or
   251 proof context in long statement form, according to the syntax of a
   252 top-level lemma.
   253 
   254 * Isar: 'obtain' takes an optional case name for the local context
   255 introduction rule (default "that").
   256 
   257 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   258 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   259 to occur.
   260 
   261 * Pure: syntax "CONST name" produces a fully internalized constant
   262 according to the current context.  This is particularly useful for
   263 syntax translations that should refer to internal constant
   264 representations independently of name spaces.
   265 
   266 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   267 instead of "FOO ". This allows multiple binder declarations to coexist
   268 in the same context.  INCOMPATIBILITY.
   269 
   270 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   271 primitive that also works in a locale context (both for constants and
   272 fixed variables).  Type declaration and internal syntactic
   273 representation of given constants retrieved from the context.
   274 
   275 * Isar/locales: new derived specification elements 'axiomatization',
   276 'definition', 'abbreviation', which support type-inference, admit
   277 object-level specifications (equality, equivalence).  See also the
   278 isar-ref manual.  Examples:
   279 
   280   axiomatization
   281     eq  (infix "===" 50) where
   282     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   283 
   284   definition "f x y = x + y + 1"
   285   definition g where "g x = f x x"
   286 
   287   abbreviation
   288     neq  (infix "=!=" 50) where
   289     "x =!= y == ~ (x === y)"
   290 
   291 These specifications may be also used in a locale context.  Then the
   292 constants being introduced depend on certain fixed parameters, and the
   293 constant name is qualified by the locale base name.  An internal
   294 abbreviation takes care for convenient input and output, making the
   295 parameters implicit and using the original short name.  See also
   296 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   297 entities from a monomorphic theory.
   298 
   299 Presently, abbreviations are only available 'in' a target locale, but
   300 not inherited by general import expressions.  Also note that
   301 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   302 'translations' in common applications.
   303 
   304 Concrete syntax is attached to specified constants in internal form,
   305 independently of name spaces.  The parse tree representation is
   306 slightly different -- use 'notation' instead of raw 'syntax', and
   307 'translations' with explicit "CONST" markup to accommodate this.
   308 
   309 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   310 the current context.  Print mode "no_abbrevs" prevents inversion of
   311 abbreviations on output.
   312 
   313 * Isar/locales: improved parameter handling:
   314 - use of locales "var" and "struct" no longer necessary;
   315 - parameter renamings are no longer required to be injective.
   316   This enables, for example, to define a locale for endomorphisms thus:
   317   locale endom = homom mult mult h.
   318 
   319 * Isar/locales: changed the way locales with predicates are defined.
   320 Instead of accumulating the specification, the imported expression is
   321 now an interpretation.  INCOMPATIBILITY: different normal form of
   322 locale expressions.  In particular, in interpretations of locales with
   323 predicates, goals repesenting already interpreted fragments are not
   324 removed automatically.  Use methods `intro_locales' and
   325 `unfold_locales'; see below.
   326 
   327 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   328 provide backward reasoning on locales predicates.  The methods are
   329 aware of interpretations and discharge corresponding goals.
   330 `intro_locales' is less aggressive then `unfold_locales' and does not
   331 unfold predicates to assumptions.
   332 
   333 * Isar/locales: the order in which locale fragments are accumulated
   334 has changed.  This enables to override declarations from fragments due
   335 to interpretations -- for example, unwanted simp rules.
   336 
   337 * Provers/induct: improved internal context management to support
   338 local fixes and defines on-the-fly.  Thus explicit meta-level
   339 connectives !! and ==> are rarely required anymore in inductive goals
   340 (using object-logic connectives for this purpose has been long
   341 obsolete anyway).  The subsequent proof patterns illustrate advanced
   342 techniques of natural induction; general datatypes and inductive sets
   343 work analogously (see also src/HOL/Lambda for realistic examples).
   344 
   345 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   346 parameters:
   347 
   348   lemma
   349     fixes n :: nat and x :: 'a
   350     assumes a: "A n x"
   351     shows "P n x"
   352     using a                     -- {* make induct insert fact a *}
   353   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   354     case 0
   355     show ?case sorry
   356   next
   357     case (Suc n)
   358     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   359     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   360     show ?case sorry
   361   qed
   362 
   363 (2) This is how to perform induction over ``expressions of a certain
   364 form'', using a locally defined inductive parameter n == "a x"
   365 together with strengthening (the latter is usually required to get
   366 sufficiently flexible induction hypotheses):
   367 
   368   lemma
   369     fixes a :: "'a => nat"
   370     assumes a: "A (a x)"
   371     shows "P (a x)"
   372     using a
   373   proof (induct n == "a x" arbitrary: x)
   374     ...
   375 
   376 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   377 particular technique.
   378 
   379 (3) This is how to perform existential reasoning ('obtains' or
   380 'obtain') by induction, while avoiding explicit object-logic
   381 encodings:
   382 
   383   lemma
   384     fixes n :: nat
   385     obtains x :: 'a where "P n x" and "Q n x"
   386   proof (induct n arbitrary: thesis)
   387     case 0
   388     obtain x where "P 0 x" and "Q 0 x" sorry
   389     then show thesis by (rule 0)
   390   next
   391     case (Suc n)
   392     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   393     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   394     then show thesis by (rule Suc.prems)
   395   qed
   396 
   397 Here the 'arbitrary: thesis' specification essentially modifies the
   398 scope of the formal thesis parameter, in order to the get the whole
   399 existence statement through the induction as expected.
   400 
   401 * Provers/induct: mutual induction rules are now specified as a list
   402 of rule sharing the same induction cases.  HOL packages usually
   403 provide foo_bar.inducts for mutually defined items foo and bar
   404 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   405 specify mutual induction rules differently, i.e. like this:
   406 
   407   (induct rule: foo_bar.inducts)
   408   (induct set: foo bar)
   409   (induct type: foo bar)
   410 
   411 The ML function ProjectRule.projections turns old-style rules into the
   412 new format.
   413 
   414 * Provers/induct: improved handling of simultaneous goals.  Instead of
   415 introducing object-level conjunction, the statement is now split into
   416 several conclusions, while the corresponding symbolic cases are
   417 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   418 explicitly.  For example:
   419 
   420   lemma
   421     fixes n :: nat
   422     shows "P n" and "Q n"
   423   proof (induct n)
   424     case 0 case 1
   425     show "P 0" sorry
   426   next
   427     case 0 case 2
   428     show "Q 0" sorry
   429   next
   430     case (Suc n) case 1
   431     note `P n` and `Q n`
   432     show "P (Suc n)" sorry
   433   next
   434     case (Suc n) case 2
   435     note `P n` and `Q n`
   436     show "Q (Suc n)" sorry
   437   qed
   438 
   439 The split into subcases may be deferred as follows -- this is
   440 particularly relevant for goal statements with local premises.
   441 
   442   lemma
   443     fixes n :: nat
   444     shows "A n ==> P n" and "B n ==> Q n"
   445   proof (induct n)
   446     case 0
   447     {
   448       case 1
   449       note `A 0`
   450       show "P 0" sorry
   451     next
   452       case 2
   453       note `B 0`
   454       show "Q 0" sorry
   455     }
   456   next
   457     case (Suc n)
   458     note `A n ==> P n` and `B n ==> Q n`
   459     {
   460       case 1
   461       note `A (Suc n)`
   462       show "P (Suc n)" sorry
   463     next
   464       case 2
   465       note `B (Suc n)`
   466       show "Q (Suc n)" sorry
   467     }
   468   qed
   469 
   470 If simultaneous goals are to be used with mutual rules, the statement
   471 needs to be structured carefully as a two-level conjunction, using
   472 lists of propositions separated by 'and':
   473 
   474   lemma
   475     shows "a : A ==> P1 a"
   476           "a : A ==> P2 a"
   477       and "b : B ==> Q1 b"
   478           "b : B ==> Q2 b"
   479           "b : B ==> Q3 b"
   480   proof (induct set: A B)
   481 
   482 * Provers/induct: support coinduction as well.  See
   483 src/HOL/Library/Coinductive_List.thy for various examples.
   484 
   485 * Attribute "symmetric" produces result with standardized schematic
   486 variables (index 0).  Potential INCOMPATIBILITY.
   487 
   488 * Simplifier: by default the simplifier trace only shows top level
   489 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   490 default. Thus there is less danger of being flooded by the trace. The
   491 trace indicates where parts have been suppressed.
   492   
   493 * Provers/classical: removed obsolete classical version of elim_format
   494 attribute; classical elim/dest rules are now treated uniformly when
   495 manipulating the claset.
   496 
   497 * Provers/classical: stricter checks to ensure that supplied intro,
   498 dest and elim rules are well-formed; dest and elim rules must have at
   499 least one premise.
   500 
   501 * Provers/classical: attributes dest/elim/intro take an optional
   502 weight argument for the rule (just as the Pure versions).  Weights are
   503 ignored by automated tools, but determine the search order of single
   504 rule steps.
   505 
   506 * Syntax: input syntax now supports dummy variable binding "%_. b",
   507 where the body does not mention the bound variable.  Note that dummy
   508 patterns implicitly depend on their context of bounds, which makes
   509 "{_. _}" match any set comprehension as expected.  Potential
   510 INCOMPATIBILITY -- parse translations need to cope with syntactic
   511 constant "_idtdummy" in the binding position.
   512 
   513 * Syntax: removed obsolete syntactic constant "_K" and its associated
   514 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   515 for example "A -> B" => "Pi A (%_. B)".
   516 
   517 * Pure: 'class_deps' command visualizes the subclass relation, using
   518 the graph browser tool.
   519 
   520 * Pure: 'print_theory' now suppresses entities with internal name
   521 (trailing "_") by default; use '!' option for full details.
   522 
   523 
   524 *** HOL ***
   525 
   526 * case expressions and primrec: missing cases now mapped to "undefined"
   527 instead of "arbitrary"
   528 
   529 * new constant "undefined" with axiom "undefined x = undefined"
   530 
   531 * new class "default" with associated constant "default"
   532 
   533 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   534     when generating code.
   535 
   536 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   537     when generating code.
   538 
   539 * Library/Commutative_Ring.thy: switched from recdef to function package;
   540     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   541 
   542 * Some steps towards more uniform lattice theory development in HOL.
   543 
   544     constants "meet" and "join" now named "inf" and "sup"
   545     constant "Meet" now named "Inf"
   546 
   547     classes "meet_semilorder" and "join_semilorder" now named
   548       "lower_semilattice" and "upper_semilattice"
   549     class "lorder" now named "lattice"
   550     class "comp_lat" now named "complete_lattice"
   551 
   552     Instantiation of lattice classes allows explicit definitions
   553     for "inf" and "sup" operations.
   554 
   555   INCOMPATIBILITY. Theorem renames:
   556 
   557     meet_left_le            ~> inf_le1
   558     meet_right_le           ~> inf_le2
   559     join_left_le            ~> sup_ge1
   560     join_right_le           ~> sup_ge2
   561     meet_join_le            ~> inf_sup_ord
   562     le_meetI                ~> le_infI
   563     join_leI                ~> le_supI
   564     le_meet                 ~> le_inf_iff
   565     le_join                 ~> ge_sup_conv
   566     meet_idempotent         ~> inf_idem
   567     join_idempotent         ~> sup_idem
   568     meet_comm               ~> inf_commute
   569     join_comm               ~> sup_commute
   570     meet_leI1               ~> le_infI1
   571     meet_leI2               ~> le_infI2
   572     le_joinI1               ~> le_supI1
   573     le_joinI2               ~> le_supI2
   574     meet_assoc              ~> inf_assoc
   575     join_assoc              ~> sup_assoc
   576     meet_left_comm          ~> inf_left_commute
   577     meet_left_idempotent    ~> inf_left_idem
   578     join_left_comm          ~> sup_left_commute
   579     join_left_idempotent    ~> sup_left_idem
   580     meet_aci                ~> inf_aci
   581     join_aci                ~> sup_aci
   582     le_def_meet             ~> le_iff_inf
   583     le_def_join             ~> le_iff_sup
   584     join_absorp2            ~> sup_absorb2
   585     join_absorp1            ~> sup_absorb1
   586     meet_absorp1            ~> inf_absorb1
   587     meet_absorp2            ~> inf_absorb2
   588     meet_join_absorp        ~> inf_sup_absorb
   589     join_meet_absorp        ~> sup_inf_absorb
   590     distrib_join_le         ~> distrib_sup_le
   591     distrib_meet_le         ~> distrib_inf_le
   592 
   593     add_meet_distrib_left   ~> add_inf_distrib_left
   594     add_join_distrib_left   ~> add_sup_distrib_left
   595     is_join_neg_meet        ~> is_join_neg_inf
   596     is_meet_neg_join        ~> is_meet_neg_sup
   597     add_meet_distrib_right  ~> add_inf_distrib_right
   598     add_join_distrib_right  ~> add_sup_distrib_right
   599     add_meet_join_distribs  ~> add_sup_inf_distribs
   600     join_eq_neg_meet        ~> sup_eq_neg_inf
   601     meet_eq_neg_join        ~> inf_eq_neg_sup
   602     add_eq_meet_join        ~> add_eq_inf_sup
   603     meet_0_imp_0            ~> inf_0_imp_0
   604     join_0_imp_0            ~> sup_0_imp_0
   605     meet_0_eq_0             ~> inf_0_eq_0
   606     join_0_eq_0             ~> sup_0_eq_0
   607     neg_meet_eq_join        ~> neg_inf_eq_sup
   608     neg_join_eq_meet        ~> neg_sup_eq_inf
   609     join_eq_if              ~> sup_eq_if
   610 
   611     mono_meet               ~> mono_inf
   612     mono_join               ~> mono_sup
   613     meet_bool_eq            ~> inf_bool_eq
   614     join_bool_eq            ~> sup_bool_eq
   615     meet_fun_eq             ~> inf_fun_eq
   616     join_fun_eq             ~> sup_fun_eq
   617     meet_set_eq             ~> inf_set_eq
   618     join_set_eq             ~> sup_set_eq
   619     meet1_iff               ~> inf1_iff
   620     meet2_iff               ~> inf2_iff
   621     meet1I                  ~> inf1I
   622     meet2I                  ~> inf2I
   623     meet1D1                 ~> inf1D1
   624     meet2D1                 ~> inf2D1
   625     meet1D2                 ~> inf1D2
   626     meet2D2                 ~> inf2D2
   627     meet1E                  ~> inf1E
   628     meet2E                  ~> inf2E
   629     join1_iff               ~> sup1_iff
   630     join2_iff               ~> sup2_iff
   631     join1I1                 ~> sup1I1
   632     join2I1                 ~> sup2I1
   633     join1I1                 ~> sup1I1
   634     join2I2                 ~> sup1I2
   635     join1CI                 ~> sup1CI
   636     join2CI                 ~> sup2CI
   637     join1E                  ~> sup1E
   638     join2E                  ~> sup2E
   639 
   640     is_meet_Meet            ~> is_meet_Inf
   641     Meet_bool_def           ~> Inf_bool_def
   642     Meet_fun_def            ~> Inf_fun_def
   643     Meet_greatest           ~> Inf_greatest
   644     Meet_lower              ~> Inf_lower
   645     Meet_set_def            ~> Inf_set_def
   646 
   647     listsp_meetI            ~> listsp_infI
   648     listsp_meet_eq          ~> listsp_inf_eq
   649 
   650     meet_min                ~> inf_min
   651     join_max                ~> sup_max
   652 
   653 * Classes "order" and "linorder": facts "refl", "trans" and
   654 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   655 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   656 
   657 * Classes "order" and "linorder": 
   658 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   659 proofs changed.
   660 
   661 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   662 INCOMPATIBILITY.
   663 
   664 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   665 INCOMPATIBILITY.
   666 
   667 * Added syntactic class "size"; overloaded constant "size" now has
   668 type "'a::size ==> bool"
   669 
   670 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   671 dvd" to "Divides.div", "Divides.mod" and "Divides.dvd". INCOMPATIBILITY.
   672 
   673 * Added method "lexicographic_order" automatically synthesizes
   674 termination relations as lexicographic combinations of size measures
   675 -- 'function' package.
   676 
   677 * HOL/records: generalised field-update to take a function on the
   678 field rather than the new value: r(|A := x|) is translated to A_update
   679 (K x) r The K-combinator that is internally used is called K_record.
   680 INCOMPATIBILITY: Usage of the plain update functions has to be
   681 adapted.
   682  
   683 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   684 0 * x = 0, which are required for a semiring.  Richer structures do
   685 not inherit from semiring_0 anymore, because this property is a
   686 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   687 semiring_0, there is more to prove, but this is mostly trivial.
   688 
   689 * axclass "recpower" was generalized to arbitrary monoids, not just
   690 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   691 commutativity or a semiring property, add the corresponding classes.
   692 
   693 * Unified locale partial_order with class definition (cf. theory
   694 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   695 
   696 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   697 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   698 Isar level, use abbreviations instead.
   699 
   700 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   701 rarely occuring name references (e.g. ``List.op mem.simps'') require
   702 renaming (e.g. ``List.memberl.simps'').
   703 
   704 * Renamed constants "0" to "HOL.zero" and "1" to "HOL.one".
   705 INCOMPATIBILITY.
   706 
   707 * Added theory Code_Generator providing class 'eq', allowing for code
   708 generation with polymorphic equality.
   709 
   710 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   711 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   712 significant changes for setting up numeral syntax for types:
   713 
   714   - new constants Numeral.pred and Numeral.succ instead
   715       of former Numeral.bin_pred and Numeral.bin_succ.
   716   - Use integer operations instead of bin_add, bin_mult and so on.
   717   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   718   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   719 
   720 See HOL/Integ/IntArith.thy for an example setup.
   721 
   722 * New top level command 'normal_form' computes the normal form of a
   723 term that may contain free variables. For example ``normal_form
   724 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   725 suitable for heavy-duty computations because the functions are
   726 compiled to ML first.
   727 
   728 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   729 25 like -->); output depends on the "iff" print_mode, the default is
   730 "A = B" (with priority 50).
   731 
   732 * Renamed constants in HOL.thy and Orderings.thy:
   733     op +   ~> HOL.plus
   734     op -   ~> HOL.minus
   735     uminus ~> HOL.uminus
   736     op *   ~> HOL.times
   737     op <   ~> Orderings.less
   738     op <=  ~> Orderings.less_eq
   739 
   740 Adaptions may be required in the following cases:
   741 
   742 a) User-defined constants using any of the names "plus", "minus", "times",
   743 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   744 may go wrong.
   745 INCOMPATIBILITY: use more specific names.
   746 
   747 b) Variables named "plus", "minus", "times", "less", "less_eq"
   748 INCOMPATIBILITY: use more specific names.
   749 
   750 c) Permutative equations (e.g. "a + b = b + a")
   751 Since the change of names also changes the order of terms, permutative
   752 rewrite rules may get applied in a different order. Experience shows that
   753 this is rarely the case (only two adaptions in the whole Isabelle
   754 distribution).
   755 INCOMPATIBILITY: rewrite proofs
   756 
   757 d) ML code directly refering to constant names
   758 This in general only affects hand-written proof tactics, simprocs and so on.
   759 INCOMPATIBILITY: grep your sourcecode and replace names.
   760 
   761 * Relations less (<) and less_eq (<=) are also available on type bool.
   762 Modified syntax to disallow nesting without explicit parentheses,
   763 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   764 
   765 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   766 
   767 * Relation composition operator "op O" now has precedence 75 and binds
   768 stronger than union and intersection. INCOMPATIBILITY.
   769 
   770 * The old set interval syntax "{m..n(}" (and relatives) has been
   771 removed.  Use "{m..<n}" (and relatives) instead.
   772 
   773 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   774 "t = s" to False (by simproc "neq_simproc").  For backward
   775 compatibility this can be disabled by ML "reset use_neq_simproc".
   776 
   777 * "m dvd n" where m and n are numbers is evaluated to True/False by
   778 simp.
   779 
   780 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   781 
   782 * Theorem setsum_mult renamed to setsum_right_distrib.
   783 
   784 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   785 ``rule'' method.
   786 
   787 * Reimplemented methods ``sat'' and ``satx'', with several
   788 improvements: goals no longer need to be stated as "<prems> ==>
   789 False", equivalences (i.e. "=" on type bool) are handled, variable
   790 names of the form "lit_<n>" are no longer reserved, significant
   791 speedup.
   792 
   793 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   794 zChaff is still supported as well.
   795 
   796 * 'inductive' and 'datatype': provide projections of mutual rules,
   797 bundled as foo_bar.inducts;
   798 
   799 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   800 Library.
   801 
   802 * Library: moved theory Accessible_Part to main HOL.
   803 
   804 * Library: added theory Coinductive_List of potentially infinite lists
   805 as greatest fixed-point.
   806 
   807 * Library: added theory AssocList which implements (finite) maps as
   808 association lists.
   809 
   810 * Added proof method ``evaluation'' for efficiently solving a goal
   811 (i.e. a boolean expression) by compiling it to ML. The goal is
   812 "proved" (via an oracle) if it evaluates to True.
   813 
   814 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   815 also when invoked by the simplifier.  This results in the simplifier
   816 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   817 fast_arith_split_limit to 0 to obtain the old behavior.
   818 
   819 * Support for hex (0x20) and binary (0b1001) numerals.
   820 
   821 * New method: reify eqs (t), where eqs are equations for an
   822 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   823 parameter, computes a term s::'b and a list xs::'a list and proves the
   824 theorem I xs s = t. This is also known as reification or quoting. The
   825 resulting theorem is applied to the subgoal to substitute t with I xs
   826 s.  If t is omitted, the subgoal itself is reified.
   827 
   828 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   829 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   830 where f is supposed to be a computable function (in the sense of code
   831 generattion). The method uses reify to compute s and xs as above then
   832 applies corr_thm and uses normalization by evaluation to "prove" f s =
   833 r and finally gets the theorem t = r, which is again applied to the
   834 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   835 
   836 * Reflection: Automatic refification now handels binding, an example
   837 is available in HOL/ex/ReflectionEx.thy
   838 
   839 
   840 *** HOL-Algebra ***
   841 
   842 * Formalisation of ideals and the quotient construction over rings.
   843 
   844 * Order and lattice theory no longer based on records.
   845 INCOMPATIBILITY.
   846 
   847 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   848 greatest_closed.  INCOMPATIBILITY.
   849 
   850 * Method algebra is now set up via an attribute.  For examples see
   851 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   852 of algebraic structures.
   853 
   854 * Renamed theory CRing to Ring.
   855 
   856 
   857 *** HOL-Complex ***
   858 
   859 * Theory Real: new method ferrack implements quantifier elimination
   860 for linear arithmetic over the reals. The quantifier elimination
   861 feature is used only for decision, for compatibility with arith. This
   862 means a goal is either solved or left unchanged, no simplification.
   863 
   864 * Real: New axiomatic classes formalize real normed vector spaces and
   865 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   866 and norm :: 'a => real.
   867 
   868 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   869 from reals into other types. The overloaded constant Reals :: 'a set
   870 is now defined as range of_real; potential INCOMPATIBILITY.
   871 
   872 * Hyperreal: Several constants that previously worked only for the
   873 reals have been generalized, so they now work over arbitrary vector
   874 spaces. Type annotations may need to be added in some cases; potential
   875 INCOMPATIBILITY.
   876 
   877   Infinitesimal  :: ('a::real_normed_vector) star set"
   878   HFinite        :: ('a::real_normed_vector) star set"
   879   HInfinite      :: ('a::real_normed_vector) star set"
   880   approx         :: ('a::real_normed_vector) star => 'a star => bool
   881   monad          :: ('a::real_normed_vector) star => 'a star set
   882   galaxy         :: ('a::real_normed_vector) star => 'a star set
   883   (NS)LIMSEQ     :: [nat, 'a::real_normed_vector, 'a] => bool
   884   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   885   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   886   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   887   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   888   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   889   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   890 
   891 * Complex: Some complex-specific constants are now abbreviations for
   892 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   893 hnorm.  Other constants have been entirely removed in favor of the
   894 polymorphic versions (INCOMPATIBILITY):
   895 
   896   approx        <-- capprox
   897   HFinite       <-- CFinite
   898   HInfinite     <-- CInfinite
   899   Infinitesimal <-- CInfinitesimal
   900   monad         <-- cmonad
   901   galaxy        <-- cgalaxy
   902   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   903   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   904   (ns)deriv     <-- (ns)cderiv
   905 
   906 
   907 *** ML ***
   908 
   909 * Context data interfaces (Theory/Proof/GenericDataFun): removed
   910 name/print, uninitialized data defaults to ad-hoc copy of empty value,
   911 init only required for impure data.  INCOMPATIBILITY: empty really
   912 need to be empty (no dependencies on theory content!)
   913 
   914 * ML within Isar: antiquotations allow to embed statically-checked
   915 formal entities in the source, referring to the context available at
   916 compile-time.  For example:
   917 
   918 ML {* @{typ "'a => 'b"} *}
   919 ML {* @{term "%x. x"} *}
   920 ML {* @{prop "x == y"} *}
   921 ML {* @{ctyp "'a => 'b"} *}
   922 ML {* @{cterm "%x. x"} *}
   923 ML {* @{cprop "x == y"} *}
   924 ML {* @{thm asm_rl} *}
   925 ML {* @{thms asm_rl} *}
   926 ML {* @{const_name c} *}
   927 ML {* @{const_syntax c} *}
   928 ML {* @{context} *}
   929 ML {* @{theory} *}
   930 ML {* @{theory Pure} *}
   931 ML {* @{simpset} *}
   932 ML {* @{claset} *}
   933 ML {* @{clasimpset} *}
   934 
   935 The same works for sources being ``used'' within an Isar context.
   936 
   937 * ML in Isar: improved error reporting; extra verbosity with
   938 Toplevel.debug enabled.
   939 
   940 * Pure/library:
   941 
   942   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   943   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   944 
   945 The semantics of "burrow" is: "take a function with *simulatanously*
   946 transforms a list of value, and apply it *simulatanously* to a list of
   947 list of values of the appropriate type". Compare this with "map" which
   948 would *not* apply its argument function simulatanously but in
   949 sequence; "fold_burrow" has an additional context.
   950 
   951 * Pure/library: functions map2 and fold2 with curried syntax for
   952 simultanous mapping and folding:
   953 
   954     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   955     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   956 
   957 * Pure/library: indexed lists - some functions in the Isabelle library
   958 treating lists over 'a as finite mappings from [0...n] to 'a have been
   959 given more convenient names and signatures reminiscent of similar
   960 functions for alists, tables, etc:
   961 
   962   val nth: 'a list -> int -> 'a 
   963   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   964   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   965 
   966 Note that fold_index starts counting at index 0, not 1 like foldln
   967 used to.
   968 
   969 * Pure/library: added general ``divide_and_conquer'' combinator on
   970 lists.
   971 
   972 * Pure/General/table.ML: the join operations now works via exceptions
   973 DUP/SAME instead of type option.  This is simpler in simple cases, and
   974 admits slightly more efficient complex applications.
   975 
   976 * Pure: datatype Context.generic joins theory/Proof.context and
   977 provides some facilities for code that works in either kind of
   978 context, notably GenericDataFun for uniform theory and proof data.
   979 
   980 * Pure: 'advanced' translation functions (parse_translation etc.) now
   981 use Context.generic instead of just theory.
   982 
   983 * Pure: simplified internal attribute type, which is now always
   984 Context.generic * thm -> Context.generic * thm.  Global (theory)
   985 vs. local (Proof.context) attributes have been discontinued, while
   986 minimizing code duplication.  Thm.rule_attribute and
   987 Thm.declaration_attribute build canonical attributes; see also
   988 structure Context for further operations on Context.generic, notably
   989 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   990 declarations and definitions.
   991 
   992 * Pure/kernel: consts certification ignores sort constraints given in
   993 signature declarations.  (This information is not relevant to the
   994 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
   995 potential INCOMPATIBILITY.
   996 
   997 * Pure: axiomatic type classes are now purely definitional, with
   998 explicit proofs of class axioms and super class relations performed
   999 internally.  See Pure/axclass.ML for the main internal interfaces --
  1000 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1001 AxClass.axiomatize_class/classrel/arity supercede
  1002 Sign.add_classes/classrel/arities.
  1003 
  1004 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1005 global/local versions on theory vs. Proof.context have been
  1006 discontinued; Attrib.syntax and Method.syntax have been adapted
  1007 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1008 attributes, methods, etc.
  1009 
  1010 * Pure: several functions of signature "... -> theory -> theory * ..."
  1011 have been reoriented to "... -> theory -> ... * theory" in order to
  1012 allow natural usage in combination with the ||>, ||>>, |-> and
  1013 fold_map combinators.
  1014 
  1015 * Pure: official theorem names (closed derivations) and additional
  1016 comments (tags) are now strictly separate.  Name hints -- which are
  1017 maintained as tags -- may be attached any time without affecting the
  1018 derivation.
  1019 
  1020 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1021 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1022 achieve the old behaviour.
  1023 
  1024 * Pure: the "Goal" constant is now called "prop", supporting a
  1025 slightly more general idea of ``protecting'' meta-level rule
  1026 statements.
  1027 
  1028 * Pure: Logic.(un)varify only works in a global context, which is now
  1029 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1030 Logic.legacy_(un)varify as temporary workaround.
  1031 
  1032 * Pure: structure Name provides scalable operations for generating
  1033 internal variable names, notably Name.variants etc.  This replaces
  1034 some popular functions from term.ML:
  1035 
  1036   Term.variant		->  Name.variant
  1037   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1038   Term.invent_names	->  Name.invent_list
  1039 
  1040 Note that low-level renaming rarely occurs in new code -- operations
  1041 from structure Variable are used instead (see below).
  1042 
  1043 * Pure: structure Variable provides fundamental operations for proper
  1044 treatment of fixed/schematic variables in a context.  For example,
  1045 Variable.import introduces fixes for schematics of given facts and
  1046 Variable.export reverses the effect (up to renaming) -- this replaces
  1047 various freeze_thaw operations.
  1048 
  1049 * Pure: structure Goal provides simple interfaces for
  1050 init/conclude/finish and tactical prove operations (replacing former
  1051 Tactic.prove).  Goal.prove is the canonical way to prove results
  1052 within a given context; Goal.prove_global is a degraded version for
  1053 theory level goals, including a global Drule.standard.  Note that
  1054 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1055 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1056 in a locale context).
  1057 
  1058 * Isar: simplified treatment of user-level errors, using exception
  1059 ERROR of string uniformly.  Function error now merely raises ERROR,
  1060 without any side effect on output channels.  The Isar toplevel takes
  1061 care of proper display of ERROR exceptions.  ML code may use plain
  1062 handle/can/try; cat_error may be used to concatenate errors like this:
  1063 
  1064   ... handle ERROR msg => cat_error msg "..."
  1065 
  1066 Toplevel ML code (run directly or through the Isar toplevel) may be
  1067 embedded into the Isar toplevel with exception display/debug like
  1068 this:
  1069 
  1070   Isar.toplevel (fn () => ...)
  1071 
  1072 INCOMPATIBILITY, removed special transform_error facilities, removed
  1073 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1074 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1075 -- use plain ERROR instead.
  1076 
  1077 * Isar: theory setup now has type (theory -> theory), instead of a
  1078 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1079 
  1080 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1081 subject to ProofContext.debug/verbose flags.
  1082 
  1083 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1084 theory before entering a proof state.  Transactions now always see a
  1085 quasi-functional intermediate checkpoint, both in interactive and
  1086 batch mode.
  1087 
  1088 * Simplifier: the simpset of a running simplification process now
  1089 contains a proof context (cf. Simplifier.the_context), which is the
  1090 very context that the initial simpset has been retrieved from (by
  1091 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1092 (solver, looper etc.) may depend on arbitrary proof data.
  1093 
  1094 * Simplifier.inherit_context inherits the proof context (plus the
  1095 local bounds) of the current simplification process; any simproc
  1096 etc. that calls the Simplifier recursively should do this!  Removed
  1097 former Simplifier.inherit_bounds, which is already included here --
  1098 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1099 specify an explicit context using Simplifier.context/theory_context.
  1100 
  1101 * Simplifier/Classical Reasoner: more abstract interfaces
  1102 change_simpset/claset for modifying the simpset/claset reference of a
  1103 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1104 INCOMPATIBILITY.
  1105 
  1106 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1107 "Trueprop" etc.
  1108 
  1109 
  1110 *** System ***
  1111 
  1112 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1113 locations -- now includes the Isabelle version identifier as well.
  1114 This simplifies use of multiple Isabelle installations.
  1115 
  1116 * isabelle-process: option -S (secure mode) disables some critical
  1117 operations, notably runtime compilation and evaluation of ML source
  1118 code.
  1119 
  1120 
  1121 New in Isabelle2005 (October 2005)
  1122 ----------------------------------
  1123 
  1124 *** General ***
  1125 
  1126 * Theory headers: the new header syntax for Isar theories is
  1127 
  1128   theory <name>
  1129   imports <theory1> ... <theoryN>
  1130   uses <file1> ... <fileM>
  1131   begin
  1132 
  1133 where the 'uses' part is optional.  The previous syntax
  1134 
  1135   theory <name> = <theory1> + ... + <theoryN>:
  1136 
  1137 will disappear in the next release.  Use isatool fixheaders to convert
  1138 existing theory files.  Note that there is no change in ancient
  1139 non-Isar theories now, but these will disappear soon.
  1140 
  1141 * Theory loader: parent theories can now also be referred to via
  1142 relative and absolute paths.
  1143 
  1144 * Command 'find_theorems' searches for a list of criteria instead of a
  1145 list of constants. Known criteria are: intro, elim, dest, name:string,
  1146 simp:term, and any term. Criteria can be preceded by '-' to select
  1147 theorems that do not match. Intro, elim, dest select theorems that
  1148 match the current goal, name:s selects theorems whose fully qualified
  1149 name contain s, and simp:term selects all simplification rules whose
  1150 lhs match term.  Any other term is interpreted as pattern and selects
  1151 all theorems matching the pattern. Available in ProofGeneral under
  1152 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1153 
  1154   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1155 
  1156 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1157 matching the current goal as introduction rule and not having "HOL."
  1158 in their name (i.e. not being defined in theory HOL).
  1159 
  1160 * Command 'thms_containing' has been discontinued in favour of
  1161 'find_theorems'; INCOMPATIBILITY.
  1162 
  1163 * Communication with Proof General is now 8bit clean, which means that
  1164 Unicode text in UTF-8 encoding may be used within theory texts (both
  1165 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1166 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1167 
  1168   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1169   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1170 
  1171 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1172 Classical Reasoner.  Typical big applications run around 2 times
  1173 faster.
  1174 
  1175 
  1176 *** Document preparation ***
  1177 
  1178 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1179 of raw sources.  Only those symbols that do not require additional
  1180 LaTeX packages (depending on comments in isabellesym.sty) are
  1181 displayed properly, everything else is left verbatim.  isatool display
  1182 and isatool print are used as front ends (these are subject to the
  1183 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1184 
  1185 * Command tags control specific markup of certain regions of text,
  1186 notably folding and hiding.  Predefined tags include "theory" (for
  1187 theory begin and end), "proof" for proof commands, and "ML" for
  1188 commands involving ML code; the additional tags "visible" and
  1189 "invisible" are unused by default.  Users may give explicit tag
  1190 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1191 interpretation of tags is determined by the LaTeX job during document
  1192 preparation: see option -V of isatool usedir, or options -n and -t of
  1193 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1194 \isadroptag.
  1195 
  1196 Several document versions may be produced at the same time via isatool
  1197 usedir (the generated index.html will link all of them).  Typical
  1198 specifications include ''-V document=theory,proof,ML'' to present
  1199 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1200 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1201 these parts without any formal replacement text.  The Isabelle site
  1202 default settings produce ''document'' and ''outline'' versions as
  1203 specified above.
  1204 
  1205 * Several new antiquotations:
  1206 
  1207   @{term_type term} prints a term with its type annotated;
  1208 
  1209   @{typeof term} prints the type of a term;
  1210 
  1211   @{const const} is the same as @{term const}, but checks that the
  1212   argument is a known logical constant;
  1213 
  1214   @{term_style style term} and @{thm_style style thm} print a term or
  1215   theorem applying a "style" to it
  1216 
  1217   @{ML text}
  1218 
  1219 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1220 definitions, equations, inequations etc., 'concl' printing only the
  1221 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1222 to print the specified premise.  TermStyle.add_style provides an ML
  1223 interface for introducing further styles.  See also the "LaTeX Sugar"
  1224 document practical applications.  The ML antiquotation prints
  1225 type-checked ML expressions verbatim.
  1226 
  1227 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1228 and 'text' support optional locale specification '(in loc)', which
  1229 specifies the default context for interpreting antiquotations.  For
  1230 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1231 
  1232 * Option 'locale=NAME' of antiquotations specifies an alternative
  1233 context interpreting the subsequent argument.  For example: @{thm
  1234 [locale=lattice] inf_assoc}.
  1235 
  1236 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1237 a proof context.
  1238 
  1239 * Proper output of antiquotations for theory commands involving a
  1240 proof context (such as 'locale' or 'theorem (in loc) ...').
  1241 
  1242 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1243 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1244 
  1245 * isatool usedir: new option -C (default true) controls whether option
  1246 -D should include a copy of the original document directory; -C false
  1247 prevents unwanted effects such as copying of administrative CVS data.
  1248 
  1249 
  1250 *** Pure ***
  1251 
  1252 * Considerably improved version of 'constdefs' command.  Now performs
  1253 automatic type-inference of declared constants; additional support for
  1254 local structure declarations (cf. locales and HOL records), see also
  1255 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1256 sequential dependencies of definitions within a single 'constdefs'
  1257 section; moreover, the declared name needs to be an identifier.  If
  1258 all fails, consider to fall back on 'consts' and 'defs' separately.
  1259 
  1260 * Improved indexed syntax and implicit structures.  First of all,
  1261 indexed syntax provides a notational device for subscripted
  1262 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1263 expressions.  Secondly, in a local context with structure
  1264 declarations, number indexes \<^sub>n or the empty index (default
  1265 number 1) refer to a certain fixed variable implicitly; option
  1266 show_structs controls printing of implicit structures.  Typical
  1267 applications of these concepts involve record types and locales.
  1268 
  1269 * New command 'no_syntax' removes grammar declarations (and
  1270 translations) resulting from the given syntax specification, which is
  1271 interpreted in the same manner as for the 'syntax' command.
  1272 
  1273 * 'Advanced' translation functions (parse_translation etc.) may depend
  1274 on the signature of the theory context being presently used for
  1275 parsing/printing, see also isar-ref manual.
  1276 
  1277 * Improved 'oracle' command provides a type-safe interface to turn an
  1278 ML expression of type theory -> T -> term into a primitive rule of
  1279 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1280 is already included here); see also FOL/ex/IffExample.thy;
  1281 INCOMPATIBILITY.
  1282 
  1283 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1284 before); "cI" is no longer bound, use "c.intro" instead.
  1285 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1286 axclasses vs. locales.
  1287 
  1288 * Improved internal renaming of symbolic identifiers -- attach primes
  1289 instead of base 26 numbers.
  1290 
  1291 * New flag show_question_marks controls printing of leading question
  1292 marks in schematic variable names.
  1293 
  1294 * In schematic variable names, *any* symbol following \<^isub> or
  1295 \<^isup> is now treated as part of the base name.  For example, the
  1296 following works without printing of awkward ".0" indexes:
  1297 
  1298   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1299     by simp
  1300 
  1301 * Inner syntax includes (*(*nested*) comments*).
  1302 
  1303 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1304 annotations as "(00...)".
  1305 
  1306 * Clear separation of logical types and nonterminals, where the latter
  1307 may only occur in 'syntax' specifications or type abbreviations.
  1308 Before that distinction was only partially implemented via type class
  1309 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1310 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1311 exotic syntax specifications may require further adaption
  1312 (e.g. Cube/Cube.thy).
  1313 
  1314 * Removed obsolete type class "logic", use the top sort {} instead.
  1315 Note that non-logical types should be declared as 'nonterminals'
  1316 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1317 specifications.
  1318 
  1319 * Attributes 'induct' and 'cases': type or set names may now be
  1320 locally fixed variables as well.
  1321 
  1322 * Simplifier: can now control the depth to which conditional rewriting
  1323 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1324 Limit.
  1325 
  1326 * Simplifier: simplification procedures may now take the current
  1327 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1328 interface), which is very useful for calling the Simplifier
  1329 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1330 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1331 low-level mk_simproc no longer applies Logic.varify internally, to
  1332 allow for use in a context of fixed variables.
  1333 
  1334 * thin_tac now works even if the assumption being deleted contains !!
  1335 or ==>.  More generally, erule now works even if the major premise of
  1336 the elimination rule contains !! or ==>.
  1337 
  1338 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1339 
  1340 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1341 from Pure, which contains all common declarations already.  Both
  1342 theories are defined via plain Isabelle/Isar .thy files.
  1343 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1344 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1345 use isatool fixcpure to adapt your theory and ML sources.
  1346 
  1347 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1348 selections of theorems in named facts via index ranges.
  1349 
  1350 * 'print_theorems': in theory mode, really print the difference
  1351 wrt. the last state (works for interactive theory development only),
  1352 in proof mode print all local facts (cf. 'print_facts');
  1353 
  1354 * 'hide': option '(open)' hides only base names.
  1355 
  1356 * More efficient treatment of intermediate checkpoints in interactive
  1357 theory development.
  1358 
  1359 * Code generator is now invoked via code_module (incremental code
  1360 generation) and code_library (modular code generation, ML structures
  1361 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1362 must be quoted when used as identifiers.
  1363 
  1364 * New 'value' command for reading, evaluating and printing terms using
  1365 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1366 quoted when used as identifier.
  1367 
  1368 
  1369 *** Locales ***
  1370 
  1371 * New commands for the interpretation of locale expressions in
  1372 theories (1), locales (2) and proof contexts (3).  These generate
  1373 proof obligations from the expression specification.  After the
  1374 obligations have been discharged, theorems of the expression are added
  1375 to the theory, target locale or proof context.  The synopsis of the
  1376 commands is a follows:
  1377 
  1378   (1) interpretation expr inst
  1379   (2) interpretation target < expr
  1380   (3) interpret expr inst
  1381 
  1382 Interpretation in theories and proof contexts require a parameter
  1383 instantiation of terms from the current context.  This is applied to
  1384 specifications and theorems of the interpreted expression.
  1385 Interpretation in locales only permits parameter renaming through the
  1386 locale expression.  Interpretation is smart in that interpretations
  1387 that are active already do not occur in proof obligations, neither are
  1388 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1389 inspect active interpretations of a particular locale.  For details,
  1390 see the Isar Reference manual.  Examples can be found in
  1391 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1392 
  1393 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1394 'interpret' instead.
  1395 
  1396 * New context element 'constrains' for adding type constraints to
  1397 parameters.
  1398 
  1399 * Context expressions: renaming of parameters with syntax
  1400 redeclaration.
  1401 
  1402 * Locale declaration: 'includes' disallowed.
  1403 
  1404 * Proper static binding of attribute syntax -- i.e. types / terms /
  1405 facts mentioned as arguments are always those of the locale definition
  1406 context, independently of the context of later invocations.  Moreover,
  1407 locale operations (renaming and type / term instantiation) are applied
  1408 to attribute arguments as expected.
  1409 
  1410 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1411 actual attributes; rare situations may require Attrib.attribute to
  1412 embed those attributes into Attrib.src that lack concrete syntax.
  1413 Attribute implementations need to cooperate properly with the static
  1414 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1415 Attrib.XXX_thm etc. already do the right thing without further
  1416 intervention.  Only unusual applications -- such as "where" or "of"
  1417 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1418 on the context and the facts involved -- may have to assign parsed
  1419 values to argument tokens explicitly.
  1420 
  1421 * Changed parameter management in theorem generation for long goal
  1422 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1423 theorem statement in rare situations.
  1424 
  1425 * Locale inspection command 'print_locale' omits notes elements.  Use
  1426 'print_locale!' to have them included in the output.
  1427 
  1428 
  1429 *** Provers ***
  1430 
  1431 * Provers/hypsubst.ML: improved version of the subst method, for
  1432 single-step rewriting: it now works in bound variable contexts. New is
  1433 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1434 rewrite a different subterm than the original subst method, which is
  1435 still available as 'simplesubst'.
  1436 
  1437 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1438 and quasi orders.
  1439 
  1440 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1441 reflexive-transitive closure of relations.
  1442 
  1443 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1444 limit (previously hard-coded with a value of 20) user-definable.
  1445 
  1446 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1447 is peformed already.  Object-logics merely need to finish their
  1448 initial simpset configuration as before.  INCOMPATIBILITY.
  1449 
  1450 
  1451 *** HOL ***
  1452 
  1453 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1454 
  1455   syntax (epsilon)
  1456     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1457 
  1458 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1459 and x-symbol; use option '-m epsilon' to get it actually printed.
  1460 Moreover, the mathematically important symbolic identifier \<epsilon>
  1461 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1462 
  1463 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1464 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1465 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1466 support corresponding Isar calculations.
  1467 
  1468 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1469 instead of ":".
  1470 
  1471 * theory SetInterval: changed the syntax for open intervals:
  1472 
  1473   Old       New
  1474   {..n(}    {..<n}
  1475   {)n..}    {n<..}
  1476   {m..n(}   {m..<n}
  1477   {)m..n}   {m<..n}
  1478   {)m..n(}  {m<..<n}
  1479 
  1480 The old syntax is still supported but will disappear in the next
  1481 release.  For conversion use the following Emacs search and replace
  1482 patterns (these are not perfect but work quite well):
  1483 
  1484   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1485   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1486 
  1487 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1488 equalities in commutative rings; method 'algebra' provides a generic
  1489 interface.
  1490 
  1491 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1492 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1493 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1494 be a tuple pattern.
  1495 
  1496 Some new syntax forms are available:
  1497 
  1498   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1499   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1500   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1501   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1502 
  1503 The latter form "\<Sum>x < k. e" used to be based on a separate
  1504 function "Summation", which has been discontinued.
  1505 
  1506 * theory Finite_Set: in structured induction proofs, the insert case
  1507 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1508 (insert F x)'.
  1509 
  1510 * The 'refute' command has been extended to support a much larger
  1511 fragment of HOL, including axiomatic type classes, constdefs and
  1512 typedefs, inductive datatypes and recursion.
  1513 
  1514 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1515 Requires zChaff with proof generation to be installed.  See
  1516 HOL/ex/SAT_Examples.thy for examples.
  1517 
  1518 * Datatype induction via method 'induct' now preserves the name of the
  1519 induction variable. For example, when proving P(xs::'a list) by
  1520 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1521 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1522 in unstructured proof scripts.
  1523 
  1524 * Reworked implementation of records.  Improved scalability for
  1525 records with many fields, avoiding performance problems for type
  1526 inference. Records are no longer composed of nested field types, but
  1527 of nested extension types. Therefore the record type only grows linear
  1528 in the number of extensions and not in the number of fields.  The
  1529 top-level (users) view on records is preserved.  Potential
  1530 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1531 old record representation. The type generated for a record is called
  1532 <record_name>_ext_type.
  1533 
  1534 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1535 proofs triggered by a record definition or a simproc (if
  1536 quick_and_dirty is enabled).  Definitions of large records can take
  1537 quite long.
  1538 
  1539 New simproc record_upd_simproc for simplification of multiple record
  1540 updates enabled by default.  Moreover, trivial updates are also
  1541 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1542 occasionally, since simplification is more powerful by default.
  1543 
  1544 * typedef: proper support for polymorphic sets, which contain extra
  1545 type-variables in the term.
  1546 
  1547 * Simplifier: automatically reasons about transitivity chains
  1548 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1549 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1550 old proofs break occasionally as simplification may now solve more
  1551 goals than previously.
  1552 
  1553 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1554 present.  Works for all partial orders (class "order"), in particular
  1555 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1556 just like y <= x.
  1557 
  1558 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1559 bound variable or a constant then the let is unfolded.  Otherwise
  1560 first a is simplified to b, and then f b is simplified to g. If
  1561 possible we abstract b from g arriving at "let x = b in h x",
  1562 otherwise we unfold the let and arrive at g.  The simproc can be
  1563 enabled/disabled by the reference use_let_simproc.  Potential
  1564 INCOMPATIBILITY since simplification is more powerful by default.
  1565 
  1566 * Classical reasoning: the meson method now accepts theorems as arguments.
  1567 
  1568 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1569 jobs to provide advice on the provability of subgoals.
  1570 
  1571 * Theory OrderedGroup and Ring_and_Field: various additions and
  1572 improvements to faciliate calculations involving equalities and
  1573 inequalities.
  1574 
  1575 The following theorems have been eliminated or modified
  1576 (INCOMPATIBILITY):
  1577 
  1578   abs_eq             now named abs_of_nonneg
  1579   abs_of_ge_0        now named abs_of_nonneg
  1580   abs_minus_eq       now named abs_of_nonpos
  1581   imp_abs_id         now named abs_of_nonneg
  1582   imp_abs_neg_id     now named abs_of_nonpos
  1583   mult_pos           now named mult_pos_pos
  1584   mult_pos_le        now named mult_nonneg_nonneg
  1585   mult_pos_neg_le    now named mult_nonneg_nonpos
  1586   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1587   mult_neg           now named mult_neg_neg
  1588   mult_neg_le        now named mult_nonpos_nonpos
  1589 
  1590 * Theory Parity: added rules for simplifying exponents.
  1591 
  1592 * Theory List:
  1593 
  1594 The following theorems have been eliminated or modified
  1595 (INCOMPATIBILITY):
  1596 
  1597   list_all_Nil       now named list_all.simps(1)
  1598   list_all_Cons      now named list_all.simps(2)
  1599   list_all_conv      now named list_all_iff
  1600   set_mem_eq         now named mem_iff
  1601 
  1602 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1603 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1604 
  1605 
  1606 *** HOL-Complex ***
  1607 
  1608 * Theory RealDef: better support for embedding natural numbers and
  1609 integers in the reals.
  1610 
  1611 The following theorems have been eliminated or modified
  1612 (INCOMPATIBILITY):
  1613 
  1614   exp_ge_add_one_self  now requires no hypotheses
  1615   real_of_int_add      reversed direction of equality (use [symmetric])
  1616   real_of_int_minus    reversed direction of equality (use [symmetric])
  1617   real_of_int_diff     reversed direction of equality (use [symmetric])
  1618   real_of_int_mult     reversed direction of equality (use [symmetric])
  1619 
  1620 * Theory RComplete: expanded support for floor and ceiling functions.
  1621 
  1622 * Theory Ln is new, with properties of the natural logarithm
  1623 
  1624 * Hyperreal: There is a new type constructor "star" for making
  1625 nonstandard types.  The old type names are now type synonyms:
  1626 
  1627   hypreal = real star
  1628   hypnat = nat star
  1629   hcomplex = complex star
  1630 
  1631 * Hyperreal: Many groups of similarly-defined constants have been
  1632 replaced by polymorphic versions (INCOMPATIBILITY):
  1633 
  1634   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1635 
  1636   starset      <-- starsetNat, starsetC
  1637   *s*          <-- *sNat*, *sc*
  1638   starset_n    <-- starsetNat_n, starsetC_n
  1639   *sn*         <-- *sNatn*, *scn*
  1640   InternalSets <-- InternalNatSets, InternalCSets
  1641 
  1642   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1643   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1644   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1645   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1646   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1647 
  1648 * Hyperreal: Many type-specific theorems have been removed in favor of
  1649 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1650 
  1651   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1652   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1653   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1654   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1655   right_minus <-- hypreal_add_minus
  1656   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1657   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1658   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1659   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1660   mult_1_right <-- hcomplex_mult_one_right
  1661   mult_zero_left <-- hcomplex_mult_zero_left
  1662   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1663   right_distrib <-- hypnat_add_mult_distrib2
  1664   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1665   right_inverse <-- hypreal_mult_inverse
  1666   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1667   order_refl <-- {hypreal,hypnat}_le_refl
  1668   order_trans <-- {hypreal,hypnat}_le_trans
  1669   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1670   order_less_le <-- {hypreal,hypnat}_less_le
  1671   linorder_linear <-- {hypreal,hypnat}_le_linear
  1672   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1673   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1674   add_nonneg_nonneg <-- hypreal_le_add_order
  1675 
  1676 * Hyperreal: Separate theorems having to do with type-specific
  1677 versions of constants have been merged into theorems that apply to the
  1678 new polymorphic constants (INCOMPATIBILITY):
  1679 
  1680   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1681   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1682   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1683   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1684   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1685   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1686   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1687   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1688   STAR_diff <-- {STAR,STARC}_diff
  1689   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1690     STARC_hcomplex_of_complex}_image_subset
  1691   starset_n_Un <-- starset{Nat,C}_n_Un
  1692   starset_n_Int <-- starset{Nat,C}_n_Int
  1693   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1694   starset_n_diff <-- starset{Nat,C}_n_diff
  1695   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1696   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1697   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1698   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1699   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1700   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1701   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1702   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1703   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1704   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1705   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1706   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1707   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1708   starfun_diff <-- starfun{C,RC,CR}_diff
  1709   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1710   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1711   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1712   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1713   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1714   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1715   starfun_Id <-- starfunC_Id
  1716   starfun_approx <-- starfun{Nat,CR}_approx
  1717   starfun_capprox <-- starfun{C,RC}_capprox
  1718   starfun_abs <-- starfunNat_rabs
  1719   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1720   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1721   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1722   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1723   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1724   starfun_add_approx <-- starfunCR_add_approx
  1725   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1726   starfun_divide <-- starfun{C,CR,RC}_divide
  1727   starfun_n <-- starfun{Nat,C}_n
  1728   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1729   starfun_n_add <-- starfun{Nat,C}_n_add
  1730   starfun_n_add_minus <-- starfunNat_n_add_minus
  1731   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1732   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1733   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1734 
  1735   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1736   star_n_minus <-- {hypreal,hcomplex}_minus
  1737   star_n_diff <-- {hypreal,hcomplex}_diff
  1738   star_n_mult <-- {hypreal,hcomplex}_mult
  1739   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1740   star_n_le <-- {hypreal,hypnat}_le
  1741   star_n_less <-- {hypreal,hypnat}_less
  1742   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1743   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1744   star_n_abs <-- hypreal_hrabs
  1745   star_n_divide <-- hcomplex_divide
  1746 
  1747   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1748   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1749   star_of_diff <-- hypreal_of_real_diff
  1750   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1751   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1752   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1753   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1754   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1755   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1756   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1757   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1758   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1759   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1760   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1761   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1762   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1763   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1764   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1765   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1766   star_of_power <-- hypreal_of_real_power
  1767   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1768 
  1769 * Hyperreal: new method "transfer" that implements the transfer
  1770 principle of nonstandard analysis. With a subgoal that mentions
  1771 nonstandard types like "'a star", the command "apply transfer"
  1772 replaces it with an equivalent one that mentions only standard types.
  1773 To be successful, all free variables must have standard types; non-
  1774 standard variables must have explicit universal quantifiers.
  1775 
  1776 * Hyperreal: A theory of Taylor series.
  1777 
  1778 
  1779 *** HOLCF ***
  1780 
  1781 * Discontinued special version of 'constdefs' (which used to support
  1782 continuous functions) in favor of the general Pure one with full
  1783 type-inference.
  1784 
  1785 * New simplification procedure for solving continuity conditions; it
  1786 is much faster on terms with many nested lambda abstractions (cubic
  1787 instead of exponential time).
  1788 
  1789 * New syntax for domain package: selector names are now optional.
  1790 Parentheses should be omitted unless argument is lazy, for example:
  1791 
  1792   domain 'a stream = cons "'a" (lazy "'a stream")
  1793 
  1794 * New command 'fixrec' for defining recursive functions with pattern
  1795 matching; defining multiple functions with mutual recursion is also
  1796 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1797 sinr, or any data constructor defined by the domain package. The given
  1798 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1799 syntax and examples.
  1800 
  1801 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1802 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1803 but the proof obligation additionally includes an admissibility
  1804 requirement. The packages generate instances of class cpo or pcpo,
  1805 with continuity and strictness theorems for Rep and Abs.
  1806 
  1807 * HOLCF: Many theorems have been renamed according to a more standard naming
  1808 scheme (INCOMPATIBILITY):
  1809 
  1810   foo_inject:  "foo$x = foo$y ==> x = y"
  1811   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1812   foo_less:    "(foo$x << foo$y) = (x << y)"
  1813   foo_strict:  "foo$UU = UU"
  1814   foo_defined: "... ==> foo$x ~= UU"
  1815   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1816 
  1817 
  1818 *** ZF ***
  1819 
  1820 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1821 including the First Isomorphism Theorem (on quotienting by the kernel
  1822 of a homomorphism).
  1823 
  1824 * ZF/Simplifier: install second copy of type solver that actually
  1825 makes use of TC rules declared to Isar proof contexts (or locales);
  1826 the old version is still required for ML proof scripts.
  1827 
  1828 
  1829 *** Cube ***
  1830 
  1831 * Converted to Isar theory format; use locales instead of axiomatic
  1832 theories.
  1833 
  1834 
  1835 *** ML ***
  1836 
  1837 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1838 for ||>, ||>>, |>>,
  1839 
  1840 * Pure/library.ML no longer defines its own option datatype, but uses
  1841 that of the SML basis, which has constructors NONE and SOME instead of
  1842 None and Some, as well as exception Option.Option instead of OPTION.
  1843 The functions the, if_none, is_some, is_none have been adapted
  1844 accordingly, while Option.map replaces apsome.
  1845 
  1846 * Pure/library.ML: the exception LIST has been given up in favour of
  1847 the standard exceptions Empty and Subscript, as well as
  1848 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1849 superceded by the standard hd and tl functions etc.
  1850 
  1851 A number of basic list functions are no longer exported to the ML
  1852 toplevel, as they are variants of predefined functions.  The following
  1853 suggests how one can translate existing code:
  1854 
  1855     rev_append xs ys = List.revAppend (xs, ys)
  1856     nth_elem (i, xs) = List.nth (xs, i)
  1857     last_elem xs = List.last xs
  1858     flat xss = List.concat xss
  1859     seq fs = List.app fs
  1860     partition P xs = List.partition P xs
  1861     mapfilter f xs = List.mapPartial f xs
  1862 
  1863 * Pure/library.ML: several combinators for linear functional
  1864 transformations, notably reverse application and composition:
  1865 
  1866   x |> f                f #> g
  1867   (x, y) |-> f          f #-> g
  1868 
  1869 * Pure/library.ML: introduced/changed precedence of infix operators:
  1870 
  1871   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1872   infix 2 ?;
  1873   infix 3 o oo ooo oooo;
  1874   infix 4 ~~ upto downto;
  1875 
  1876 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1877 infix operators.
  1878 
  1879 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1880 fold_map support linear functional transformations and nesting.  For
  1881 example:
  1882 
  1883   fold f [x1, ..., xN] y =
  1884     y |> f x1 |> ... |> f xN
  1885 
  1886   (fold o fold) f [xs1, ..., xsN] y =
  1887     y |> fold f xs1 |> ... |> fold f xsN
  1888 
  1889   fold f [x1, ..., xN] =
  1890     f x1 #> ... #> f xN
  1891 
  1892   (fold o fold) f [xs1, ..., xsN] =
  1893     fold f xs1 #> ... #> fold f xsN
  1894 
  1895 * Pure/library.ML: the following selectors on type 'a option are
  1896 available:
  1897 
  1898   the:               'a option -> 'a  (*partial*)
  1899   these:             'a option -> 'a  where 'a = 'b list
  1900   the_default: 'a -> 'a option -> 'a
  1901   the_list:          'a option -> 'a list
  1902 
  1903 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1904 basic operations for association lists, following natural argument
  1905 order; moreover the explicit equality predicate passed here avoids
  1906 potentially expensive polymorphic runtime equality checks.
  1907 The old functions may be expressed as follows:
  1908 
  1909   assoc = uncurry (AList.lookup (op =))
  1910   assocs = these oo AList.lookup (op =)
  1911   overwrite = uncurry (AList.update (op =)) o swap
  1912 
  1913 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1914 
  1915   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1916   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1917 
  1918 replacing make_keylist and keyfilter (occassionally used)
  1919 Naive rewrites:
  1920 
  1921   make_keylist = AList.make
  1922   keyfilter = AList.find (op =)
  1923 
  1924 * eq_fst and eq_snd now take explicit equality parameter, thus
  1925   avoiding eqtypes. Naive rewrites:
  1926 
  1927     eq_fst = eq_fst (op =)
  1928     eq_snd = eq_snd (op =)
  1929 
  1930 * Removed deprecated apl and apr (rarely used).
  1931   Naive rewrites:
  1932 
  1933     apl (n, op) =>>= curry op n
  1934     apr (op, m) =>>= fn n => op (n, m)
  1935 
  1936 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1937 provides a reasonably efficient light-weight implementation of sets as
  1938 lists.
  1939 
  1940 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1941 few new operations; existing lookup and update are now curried to
  1942 follow natural argument order (for use with fold etc.);
  1943 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1944 
  1945 * Pure/General: output via the Isabelle channels of
  1946 writeln/warning/error etc. is now passed through Output.output, with a
  1947 hook for arbitrary transformations depending on the print_mode
  1948 (cf. Output.add_mode -- the first active mode that provides a output
  1949 function wins).  Already formatted output may be embedded into further
  1950 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1951 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1952 accommodate easy composition of diagnostic messages etc.  Programmers
  1953 rarely need to care about Output.output or Output.raw at all, with
  1954 some notable exceptions: Output.output is required when bypassing the
  1955 standard channels (writeln etc.), or in token translations to produce
  1956 properly formatted results; Output.raw is required when capturing
  1957 already output material that will eventually be presented to the user
  1958 a second time.  For the default print mode, both Output.output and
  1959 Output.raw have no effect.
  1960 
  1961 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1962 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1963 cumulative results are displayed at the end of a batch session.
  1964 
  1965 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1966 replaced by File.platform_path and File.shell_path (with appropriate
  1967 hooks).  This provides a clean interface for unusual systems where the
  1968 internal and external process view of file names are different.
  1969 
  1970 * Pure: more efficient orders for basic syntactic entities: added
  1971 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1972 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1973 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1974 orders now -- potential INCOMPATIBILITY for code that depends on a
  1975 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1976 Library.sort_strings on result).
  1977 
  1978 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1979 fold_types traverse types/terms from left to right, observing natural
  1980 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1981 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1982 
  1983 * Pure: name spaces have been refined, with significant changes of the
  1984 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1985 to extern(_table).  The plain name entry path is superceded by a
  1986 general 'naming' context, which also includes the 'policy' to produce
  1987 a fully qualified name and external accesses of a fully qualified
  1988 name; NameSpace.extend is superceded by context dependent
  1989 Sign.declare_name.  Several theory and proof context operations modify
  1990 the naming context.  Especially note Theory.restore_naming and
  1991 ProofContext.restore_naming to get back to a sane state; note that
  1992 Theory.add_path is no longer sufficient to recover from
  1993 Theory.absolute_path in particular.
  1994 
  1995 * Pure: new flags short_names (default false) and unique_names
  1996 (default true) for controlling output of qualified names.  If
  1997 short_names is set, names are printed unqualified.  If unique_names is
  1998 reset, the name prefix is reduced to the minimum required to achieve
  1999 the original result when interning again, even if there is an overlap
  2000 with earlier declarations.
  2001 
  2002 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2003 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2004 (useful for printing error messages).  INCOMPATIBILITY.
  2005 
  2006 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2007 Theory.theory are now identified, referring to the universal
  2008 Context.theory (see Pure/context.ML).  Actual signature and theory
  2009 content is managed as theory data.  The old code and interfaces were
  2010 spread over many files and structures; the new arrangement introduces
  2011 considerable INCOMPATIBILITY to gain more clarity:
  2012 
  2013   Context -- theory management operations (name, identity, inclusion,
  2014     parents, ancestors, merge, etc.), plus generic theory data;
  2015 
  2016   Sign -- logical signature and syntax operations (declaring consts,
  2017     types, etc.), plus certify/read for common entities;
  2018 
  2019   Theory -- logical theory operations (stating axioms, definitions,
  2020     oracles), plus a copy of logical signature operations (consts,
  2021     types, etc.); also a few basic management operations (Theory.copy,
  2022     Theory.merge, etc.)
  2023 
  2024 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2025 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2026 for convenience -- they merely return the theory.
  2027 
  2028 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2029 
  2030 * Pure: the Isar proof context type is already defined early in Pure
  2031 as Context.proof (note that ProofContext.context and Proof.context are
  2032 aliases, where the latter is the preferred name).  This enables other
  2033 Isabelle components to refer to that type even before Isar is present.
  2034 
  2035 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2036 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2037 any of these kinds.  For example, Sign.intern typeK is now
  2038 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2039 Theory.hide_types.  Also note that former
  2040 Theory.hide_classes/types/consts are now
  2041 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2042 internalize their arguments!  INCOMPATIBILITY.
  2043 
  2044 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2045 datatype thmref (with constructors Name and NameSelection) instead of
  2046 plain string -- INCOMPATIBILITY;
  2047 
  2048 * Pure: cases produced by proof methods specify options, where NONE
  2049 means to remove case bindings -- INCOMPATIBILITY in
  2050 (RAW_)METHOD_CASES.
  2051 
  2052 * Pure: the following operations retrieve axioms or theorems from a
  2053 theory node or theory hierarchy, respectively:
  2054 
  2055   Theory.axioms_of: theory -> (string * term) list
  2056   Theory.all_axioms_of: theory -> (string * term) list
  2057   PureThy.thms_of: theory -> (string * thm) list
  2058   PureThy.all_thms_of: theory -> (string * thm) list
  2059 
  2060 * Pure: print_tac now outputs the goal through the trace channel.
  2061 
  2062 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2063 Reference Toplevel.debug (default false) controls detailed printing
  2064 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2065 controls execution profiling -- set to 1 for time and 2 for space
  2066 (both increase the runtime).
  2067 
  2068 * Isar session: The initial use of ROOT.ML is now always timed,
  2069 i.e. the log will show the actual process times, in contrast to the
  2070 elapsed wall-clock time that the outer shell wrapper produces.
  2071 
  2072 * Simplifier: improved handling of bound variables (nameless
  2073 representation, avoid allocating new strings).  Simprocs that invoke
  2074 the Simplifier recursively should use Simplifier.inherit_bounds to
  2075 avoid local name clashes.  Failure to do so produces warnings
  2076 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2077 for further details.
  2078 
  2079 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2080 bindings for all theorems stored within a given theory; this may help
  2081 in porting non-Isar theories to Isar ones, while keeping ML proof
  2082 scripts for the time being.
  2083 
  2084 * ML operator HTML.with_charset specifies the charset begin used for
  2085 generated HTML files.  For example:
  2086 
  2087   HTML.with_charset "utf-8" use_thy "Hebrew";
  2088   HTML.with_charset "utf-8" use_thy "Chinese";
  2089 
  2090 
  2091 *** System ***
  2092 
  2093 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2094 isabelle, isatool etc.).
  2095 
  2096 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2097 isatool doc, isatool mkdir, display_drafts etc.).
  2098 
  2099 * isatool usedir: option -f allows specification of the ML file to be
  2100 used by Isabelle; default is ROOT.ML.
  2101 
  2102 * New isatool version outputs the version identifier of the Isabelle
  2103 distribution being used.
  2104 
  2105 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2106 (containing Boolean satisfiability problems) into Isabelle/HOL
  2107 theories.
  2108 
  2109 
  2110 
  2111 New in Isabelle2004 (April 2004)
  2112 --------------------------------
  2113 
  2114 *** General ***
  2115 
  2116 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2117   Replaces linorder.ML.
  2118 
  2119 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2120   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2121   (\<a>...\<z>), are now considered normal letters, and can therefore
  2122   be used anywhere where an ASCII letter (a...zA...Z) has until
  2123   now. COMPATIBILITY: This obviously changes the parsing of some
  2124   terms, especially where a symbol has been used as a binder, say
  2125   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2126   as an identifier.  Fix it by inserting a space around former
  2127   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2128   existing theory and ML files.
  2129 
  2130 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2131 
  2132 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2133   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2134   a normal (but invisible) letter. For multiple letter subscripts repeat
  2135   \<^isub> like this: x\<^isub>1\<^isub>2.
  2136 
  2137 * Pure: There are now sub-/superscripts that can span more than one
  2138   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2139   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2140   superscript. The new control characters are not identifier parts.
  2141 
  2142 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2143   content of "..." to the latex file instead of \isacntrl... . The "..."
  2144   may consist of any printable characters excluding the end bracket >.
  2145 
  2146 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2147   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2148   declare constants "final", which prevents their being given a definition
  2149   later.  It is useful for constants whose behaviour is fixed axiomatically
  2150   rather than definitionally, such as the meta-logic connectives.
  2151 
  2152 * Pure: 'instance' now handles general arities with general sorts
  2153   (i.e. intersections of classes),
  2154 
  2155 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2156   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2157   It can be changed to alter the colors/layout of generated pages.
  2158 
  2159 
  2160 *** Isar ***
  2161 
  2162 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2163   cut_tac, subgoal_tac and thin_tac:
  2164   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2165     locales are no longer forced to write Isar proof scripts.
  2166     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2167     emulations.
  2168   - INCOMPATIBILITY: names of variables to be instantiated may no
  2169     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2170     This is consistent with the instantiation attribute "where".
  2171 
  2172 * Attributes "where" and "of":
  2173   - Now take type variables of instantiated theorem into account when reading
  2174     the instantiation string.  This fixes a bug that caused instantiated
  2175     theorems to have too special types in some circumstances.
  2176   - "where" permits explicit instantiations of type variables.
  2177 
  2178 * Calculation commands "moreover" and "also" no longer interfere with
  2179   current facts ("this"), admitting arbitrary combinations with "then"
  2180   and derived forms.
  2181 
  2182 * Locales:
  2183   - Goal statements involving the context element "includes" no longer
  2184     generate theorems with internal delta predicates (those ending on
  2185     "_axioms") in the premise.
  2186     Resolve particular premise with <locale>.intro to obtain old form.
  2187   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2188     specification and "includes" elements in goal statement.
  2189   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2190     [intro?] and [elim?] (respectively) by default.
  2191   - Experimental command for instantiation of locales in proof contexts:
  2192         instantiate <label>[<attrs>]: <loc>
  2193     Instantiates locale <loc> and adds all its theorems to the current context
  2194     taking into account their attributes.  Label and attrs are optional
  2195     modifiers, like in theorem declarations.  If present, names of
  2196     instantiated theorems are qualified with <label>, and the attributes
  2197     <attrs> are applied after any attributes these theorems might have already.
  2198       If the locale has assumptions, a chained fact of the form
  2199     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2200     are derived.  The command does not support old-style locales declared
  2201     with "locale (open)".
  2202       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2203 
  2204 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2205   (Isar) contexts.
  2206 
  2207 
  2208 *** HOL ***
  2209 
  2210 * Proof import: new image HOL4 contains the imported library from
  2211   the HOL4 system with about 2500 theorems. It is imported by
  2212   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2213   can be used like any other Isabelle image.  See
  2214   HOL/Import/HOL/README for more information.
  2215 
  2216 * Simplifier:
  2217   - Much improved handling of linear and partial orders.
  2218     Reasoners for linear and partial orders are set up for type classes
  2219     "linorder" and "order" respectively, and are added to the default simpset
  2220     as solvers.  This means that the simplifier can build transitivity chains
  2221     to solve goals from the assumptions.
  2222   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2223     of blast or auto after simplification become unnecessary because the goal
  2224     is solved by simplification already.
  2225 
  2226 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2227     all proved in axiomatic type classes for semirings, rings and fields.
  2228 
  2229 * Numerics:
  2230   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2231     now formalized using the Ring_and_Field theory mentioned above.
  2232   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2233     than before, because now they are set up once in a generic manner.
  2234   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2235     Look for the general versions in Ring_and_Field (and Power if they concern
  2236     exponentiation).
  2237 
  2238 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2239 
  2240 * Records:
  2241   - Record types are now by default printed with their type abbreviation
  2242     instead of the list of all field types. This can be configured via
  2243     the reference "print_record_type_abbr".
  2244   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2245     (not enabled by default).
  2246   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2247     EX x. x = sel r to True (not enabled by default).
  2248   - Tactic "record_split_simp_tac" to split and simplify records added.
  2249 
  2250 * 'specification' command added, allowing for definition by
  2251   specification.  There is also an 'ax_specification' command that
  2252   introduces the new constants axiomatically.
  2253 
  2254 * arith(_tac) is now able to generate counterexamples for reals as well.
  2255 
  2256 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2257 
  2258 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2259   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2260 
  2261 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2262   matrix theory to linear programming.
  2263 
  2264 * Unions and Intersections:
  2265   The latex output syntax of UN and INT has been changed
  2266   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2267   i.e. the index formulae has become a subscript.
  2268   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2269 
  2270 * Unions and Intersections over Intervals:
  2271   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2272   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2273   like in normal math, and corresponding versions for < and for intersection.
  2274 
  2275 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2276   lexicographic dictonary ordering has been added as "lexord".
  2277 
  2278 * ML: the legacy theory structures Int and List have been removed. They had
  2279   conflicted with ML Basis Library structures having the same names.
  2280 
  2281 * 'refute' command added to search for (finite) countermodels.  Only works
  2282   for a fragment of HOL.  The installation of an external SAT solver is
  2283   highly recommended.  See "HOL/Refute.thy" for details.
  2284 
  2285 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2286   formulae under an assignment of free variables to random values.
  2287   In contrast to 'refute', it can deal with inductive datatypes,
  2288   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2289   for examples.
  2290 
  2291 
  2292 *** HOLCF ***
  2293 
  2294 * Streams now come with concatenation and are part of the HOLCF image
  2295 
  2296 
  2297 
  2298 New in Isabelle2003 (May 2003)
  2299 ------------------------------
  2300 
  2301 *** General ***
  2302 
  2303 * Provers/simplifier:
  2304 
  2305   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2306     Assumptions are now subject to complete mutual simplification,
  2307     not just from left to right. The simplifier now preserves
  2308     the order of assumptions.
  2309 
  2310     Potential INCOMPATIBILITY:
  2311 
  2312     -- simp sometimes diverges where the old version did
  2313        not, e.g. invoking simp on the goal
  2314 
  2315         [| P (f x); y = x; f x = f y |] ==> Q
  2316 
  2317        now gives rise to the infinite reduction sequence
  2318 
  2319         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2320 
  2321        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2322        kind of problem.
  2323 
  2324     -- Tactics combining classical reasoner and simplification (such as auto)
  2325        are also affected by this change, because many of them rely on
  2326        simp. They may sometimes diverge as well or yield a different numbers
  2327        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2328        in case of problems. Sometimes subsequent calls to the classical
  2329        reasoner will fail because a preceeding call to the simplifier too
  2330        eagerly simplified the goal, e.g. deleted redundant premises.
  2331 
  2332   - The simplifier trace now shows the names of the applied rewrite rules
  2333 
  2334   - You can limit the number of recursive invocations of the simplifier
  2335     during conditional rewriting (where the simplifie tries to solve the
  2336     conditions before applying the rewrite rule):
  2337     ML "simp_depth_limit := n"
  2338     where n is an integer. Thus you can force termination where previously
  2339     the simplifier would diverge.
  2340 
  2341   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2342 
  2343   - No longer aborts on failed congruence proof.  Instead, the
  2344     congruence is ignored.
  2345 
  2346 * Pure: New generic framework for extracting programs from constructive
  2347   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2348   as HOL/Extraction for some case studies.
  2349 
  2350 * Pure: The main goal of the proof state is no longer shown by default, only
  2351 the subgoals. This behaviour is controlled by a new flag.
  2352    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2353 (ML: Proof.show_main_goal).
  2354 
  2355 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2356 rules whose conclusion matches subgoal 1:
  2357       PG menu: Isabelle/Isar -> Show me -> matching rules
  2358 The rules are ordered by how closely they match the subgoal.
  2359 In particular, rules that solve a subgoal outright are displayed first
  2360 (or rather last, the way they are printed).
  2361 (ML: ProofGeneral.print_intros())
  2362 
  2363 * Pure: New flag trace_unify_fail causes unification to print
  2364 diagnostic information (PG: in trace buffer) when it fails. This is
  2365 useful for figuring out why single step proofs like rule, erule or
  2366 assumption failed.
  2367 
  2368 * Pure: Locale specifications now produce predicate definitions
  2369 according to the body of text (covering assumptions modulo local
  2370 definitions); predicate "loc_axioms" covers newly introduced text,
  2371 while "loc" is cumulative wrt. all included locale expressions; the
  2372 latter view is presented only on export into the global theory
  2373 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2374 on the old view without predicates;
  2375 
  2376 * Pure: predefined locales "var" and "struct" are useful for sharing
  2377 parameters (as in CASL, for example); just specify something like
  2378 ``var x + var y + struct M'' as import;
  2379 
  2380 * Pure: improved thms_containing: proper indexing of facts instead of
  2381 raw theorems; check validity of results wrt. current name space;
  2382 include local facts of proof configuration (also covers active
  2383 locales), cover fixed variables in index; may use "_" in term
  2384 specification; an optional limit for the number of printed facts may
  2385 be given (the default is 40);
  2386 
  2387 * Pure: disallow duplicate fact bindings within new-style theory files
  2388 (batch-mode only);
  2389 
  2390 * Provers: improved induct method: assumptions introduced by case
  2391 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2392 the goal statement); "foo" still refers to all facts collectively;
  2393 
  2394 * Provers: the function blast.overloaded has been removed: all constants
  2395 are regarded as potentially overloaded, which improves robustness in exchange
  2396 for slight decrease in efficiency;
  2397 
  2398 * Provers/linorder: New generic prover for transitivity reasoning over
  2399 linear orders.  Note: this prover is not efficient!
  2400 
  2401 * Isar: preview of problems to finish 'show' now produce an error
  2402 rather than just a warning (in interactive mode);
  2403 
  2404 
  2405 *** HOL ***
  2406 
  2407 * arith(_tac)
  2408 
  2409  - Produces a counter example if it cannot prove a goal.
  2410    Note that the counter example may be spurious if the goal is not a formula
  2411    of quantifier-free linear arithmetic.
  2412    In ProofGeneral the counter example appears in the trace buffer.
  2413 
  2414  - Knows about div k and mod k where k is a numeral of type nat or int.
  2415 
  2416  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2417    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2418    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2419 
  2420 * simp's arithmetic capabilities have been enhanced a bit: it now
  2421 takes ~= in premises into account (by performing a case split);
  2422 
  2423 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2424 are distributed over a sum of terms;
  2425 
  2426 * New tactic "trans_tac" and method "trans" instantiate
  2427 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2428 "<=", "<" and "=").
  2429 
  2430 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2431 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2432 
  2433 * 'typedef' command has new option "open" to suppress the set
  2434 definition;
  2435 
  2436 * functions Min and Max on finite sets have been introduced (theory
  2437 Finite_Set);
  2438 
  2439 * attribute [symmetric] now works for relations as well; it turns
  2440 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2441 
  2442 * induct over a !!-quantified statement (say !!x1..xn):
  2443   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2444 
  2445 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2446 %x. None. Warning: empty_def now refers to the previously hidden definition
  2447 of the empty set.
  2448 
  2449 * Algebra: formalization of classical algebra.  Intended as base for
  2450 any algebraic development in Isabelle.  Currently covers group theory
  2451 (up to Sylow's theorem) and ring theory (Universal Property of
  2452 Univariate Polynomials).  Contributions welcome;
  2453 
  2454 * GroupTheory: deleted, since its material has been moved to Algebra;
  2455 
  2456 * Complex: new directory of the complex numbers with numeric constants,
  2457 nonstandard complex numbers, and some complex analysis, standard and
  2458 nonstandard (Jacques Fleuriot);
  2459 
  2460 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2461 
  2462 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2463 Fleuriot);
  2464 
  2465 * Real/HahnBanach: updated and adapted to locales;
  2466 
  2467 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2468 Gray and Kramer);
  2469 
  2470 * UNITY: added the Meier-Sanders theory of progress sets;
  2471 
  2472 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2473 as abstract algorithms, instantiated to the JVM;
  2474 
  2475 * Bali: Java source language formalization. Type system, operational
  2476 semantics, axiomatic semantics. Supported language features:
  2477 classes, interfaces, objects,virtual methods, static methods,
  2478 static/instance fields, arrays, access modifiers, definite
  2479 assignment, exceptions.
  2480 
  2481 
  2482 *** ZF ***
  2483 
  2484 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2485 universe, etc.);
  2486 
  2487 * Main ZF: virtually all theories converted to new-style format;
  2488 
  2489 
  2490 *** ML ***
  2491 
  2492 * Pure: Tactic.prove provides sane interface for internal proofs;
  2493 omits the infamous "standard" operation, so this is more appropriate
  2494 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2495 
  2496 * Pure: improved error reporting of simprocs;
  2497 
  2498 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2499 up simprocs;
  2500 
  2501 
  2502 *** Document preparation ***
  2503 
  2504 * uses \par instead of \\ for line breaks in theory text. This may
  2505 shift some page breaks in large documents. To get the old behaviour
  2506 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2507 
  2508 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2509 other packages
  2510 
  2511 * \<euro> now needs package babel/greek instead of marvosym (which
  2512 broke \Rightarrow)
  2513 
  2514 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2515 textcomp package)
  2516 
  2517 
  2518 
  2519 New in Isabelle2002 (March 2002)
  2520 --------------------------------
  2521 
  2522 *** Document preparation ***
  2523 
  2524 * greatly simplified document preparation setup, including more
  2525 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2526 instructive isatool mkdir; users should basically be able to get
  2527 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2528 users may run a separate document processing stage manually like this:
  2529 "isatool usedir -D output HOL Test && isatool document Test/output";
  2530 
  2531 * theory dependency graph may now be incorporated into documents;
  2532 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2533 with \includegraphics of LaTeX;
  2534 
  2535 * proper spacing of consecutive markup elements, especially text
  2536 blocks after section headings;
  2537 
  2538 * support bold style (for single symbols only), input syntax is like
  2539 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2540 
  2541 * \<bullet> is now output as bold \cdot by default, which looks much
  2542 better in printed text;
  2543 
  2544 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2545 note that these symbols are currently unavailable in Proof General /
  2546 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2547 
  2548 * isatool latex no longer depends on changed TEXINPUTS, instead
  2549 isatool document copies the Isabelle style files to the target
  2550 location;
  2551 
  2552 
  2553 *** Isar ***
  2554 
  2555 * Pure/Provers: improved proof by cases and induction;
  2556   - 'case' command admits impromptu naming of parameters (such as
  2557     "case (Suc n)");
  2558   - 'induct' method divinates rule instantiation from the inductive
  2559     claim; no longer requires excessive ?P bindings for proper
  2560     instantiation of cases;
  2561   - 'induct' method properly enumerates all possibilities of set/type
  2562     rules; as a consequence facts may be also passed through *type*
  2563     rules without further ado;
  2564   - 'induct' method now derives symbolic cases from the *rulified*
  2565     rule (before it used to rulify cases stemming from the internal
  2566     atomized version); this means that the context of a non-atomic
  2567     statement becomes is included in the hypothesis, avoiding the
  2568     slightly cumbersome show "PROP ?case" form;
  2569   - 'induct' may now use elim-style induction rules without chaining
  2570     facts, using ``missing'' premises from the goal state; this allows
  2571     rules stemming from inductive sets to be applied in unstructured
  2572     scripts, while still benefitting from proper handling of non-atomic
  2573     statements; NB: major inductive premises need to be put first, all
  2574     the rest of the goal is passed through the induction;
  2575   - 'induct' proper support for mutual induction involving non-atomic
  2576     rule statements (uses the new concept of simultaneous goals, see
  2577     below);
  2578   - append all possible rule selections, but only use the first
  2579     success (no backtracking);
  2580   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2581   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2582   - added 'print_induct_rules' (covered by help item in recent Proof
  2583     General versions);
  2584   - moved induct/cases attributes to Pure, methods to Provers;
  2585   - generic method setup instantiated for FOL and HOL;
  2586 
  2587 * Pure: support multiple simultaneous goal statements, for example
  2588 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2589 meta-level mechanism, this acts as if several individual goals had
  2590 been stated separately; in particular common proof methods need to be
  2591 repeated in order to cover all claims; note that a single elimination
  2592 step is *not* sufficient to establish the two conjunctions, so this
  2593 fails:
  2594 
  2595   assume "A & B" then have A and B ..   (*".." fails*)
  2596 
  2597 better use "obtain" in situations as above; alternative refer to
  2598 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2599 
  2600 * Pure: proper integration with ``locales''; unlike the original
  2601 version by Florian Kammller, Isar locales package high-level proof
  2602 contexts rather than raw logical ones (e.g. we admit to include
  2603 attributes everywhere); operations on locales include merge and
  2604 rename; support for implicit arguments (``structures''); simultaneous
  2605 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2606 some examples;
  2607 
  2608 * Pure: the following commands have been ``localized'', supporting a
  2609 target locale specification "(in name)": 'lemma', 'theorem',
  2610 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2611 stored both within the locale and at the theory level (exported and
  2612 qualified by the locale name);
  2613 
  2614 * Pure: theory goals may now be specified in ``long'' form, with
  2615 ad-hoc contexts consisting of arbitrary locale elements. for example
  2616 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2617 definitions may be given, too); the result is a meta-level rule with
  2618 the context elements being discharged in the obvious way;
  2619 
  2620 * Pure: new proof command 'using' allows to augment currently used
  2621 facts after a goal statement ('using' is syntactically analogous to
  2622 'apply', but acts on the goal's facts only); this allows chained facts
  2623 to be separated into parts given before and after a claim, as in
  2624 ``from a and b have C using d and e <proof>'';
  2625 
  2626 * Pure: renamed "antecedent" case to "rule_context";
  2627 
  2628 * Pure: new 'judgment' command records explicit information about the
  2629 object-logic embedding (used by several tools internally); no longer
  2630 use hard-wired "Trueprop";
  2631 
  2632 * Pure: added 'corollary' command;
  2633 
  2634 * Pure: fixed 'token_translation' command;
  2635 
  2636 * Pure: removed obsolete 'exported' attribute;
  2637 
  2638 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2639 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2640 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2641 
  2642 * Pure: method 'atomize' presents local goal premises as object-level
  2643 statements (atomic meta-level propositions); setup controlled via
  2644 rewrite rules declarations of 'atomize' attribute; example
  2645 application: 'induct' method with proper rule statements in improper
  2646 proof *scripts*;
  2647 
  2648 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2649 now consider the syntactic context of assumptions, giving a better
  2650 chance to get type-inference of the arguments right (this is
  2651 especially important for locales);
  2652 
  2653 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2654 mode;
  2655 
  2656 * Pure/obtain: the formal conclusion "thesis", being marked as
  2657 ``internal'', may no longer be reference directly in the text;
  2658 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2659 situations;
  2660 
  2661 * Pure: generic 'sym' attribute which declares a rule both as pure
  2662 'elim?' and for the 'symmetric' operation;
  2663 
  2664 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2665 text; the fixed correlation with particular command syntax has been
  2666 discontinued;
  2667 
  2668 * Pure: new method 'rules' is particularly well-suited for proof
  2669 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2670 but often produces more compact proof terms with less detours;
  2671 
  2672 * Pure/Provers/classical: simplified integration with pure rule
  2673 attributes and methods; the classical "intro?/elim?/dest?"
  2674 declarations coincide with the pure ones; the "rule" method no longer
  2675 includes classically swapped intros; "intro" and "elim" methods no
  2676 longer pick rules from the context; also got rid of ML declarations
  2677 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2678 INCOMPATIBILITY;
  2679 
  2680 * Provers/classical: attribute 'swapped' produces classical inversions
  2681 of introduction rules;
  2682 
  2683 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2684 rules instead of full simplifier context; 'iff' attribute handles
  2685 conditional rules;
  2686 
  2687 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2688 
  2689 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2690 "(permissive)" option to recover old behavior;
  2691 
  2692 * HOL: 'inductive' no longer features separate (collective) attributes
  2693 for 'intros' (was found too confusing);
  2694 
  2695 * HOL: properly declared induction rules less_induct and
  2696 wf_induct_rule;
  2697 
  2698 
  2699 *** HOL ***
  2700 
  2701 * HOL: moved over to sane numeral syntax; the new policy is as
  2702 follows:
  2703 
  2704   - 0 and 1 are polymorphic constants, which are defined on any
  2705   numeric type (nat, int, real etc.);
  2706 
  2707   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2708   binary representation internally;
  2709 
  2710   - type nat has special constructor Suc, and generally prefers Suc 0
  2711   over 1::nat and Suc (Suc 0) over 2::nat;
  2712 
  2713 This change may cause significant problems of INCOMPATIBILITY; here
  2714 are some hints on converting existing sources:
  2715 
  2716   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2717   entities, so expressions involving "-" (unary or binary minus) need
  2718   to be spaced properly;
  2719 
  2720   - existing occurrences of "1" may need to be constraint "1::nat" or
  2721   even replaced by Suc 0; similar for old "2";
  2722 
  2723   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2724 
  2725   - remove all special provisions on numerals in proofs;
  2726 
  2727 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2728 representation (depends on bin_arith_simps in the default context);
  2729 
  2730 * HOL: symbolic syntax for x^2 (numeral 2);
  2731 
  2732 * HOL: the class of all HOL types is now called "type" rather than
  2733 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2734 in axclass/classes, instance/arities, and (usually rare) occurrences
  2735 in typings (of consts etc.); internally the class is called
  2736 "HOL.type", ML programs should refer to HOLogic.typeS;
  2737 
  2738 * HOL/record package improvements:
  2739   - new derived operations "fields" to build a partial record section,
  2740     "extend" to promote a fixed record to a record scheme, and
  2741     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2742     declared as simp by default;
  2743   - shared operations ("more", "fields", etc.) now need to be always
  2744     qualified) --- potential INCOMPATIBILITY;
  2745   - removed "make_scheme" operations (use "make" with "extend") --
  2746     INCOMPATIBILITY;
  2747   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2748   - provides cases/induct rules for use with corresponding Isar
  2749     methods (for concrete records, record schemes, concrete more
  2750     parts, and schematic more parts -- in that order);
  2751   - internal definitions directly based on a light-weight abstract
  2752     theory of product types over typedef rather than datatype;
  2753 
  2754 * HOL: generic code generator for generating executable ML code from
  2755 specifications; specific support for HOL constructs such as inductive
  2756 datatypes and sets, as well as recursive functions; can be invoked
  2757 via 'generate_code' theory section;
  2758 
  2759 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2760 
  2761 * HOL: consolidated and renamed several theories.  In particular:
  2762         Ord.thy has been absorbed into HOL.thy
  2763         String.thy has been absorbed into List.thy
  2764 
  2765 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2766 (beware of argument permutation!);
  2767 
  2768 * HOL: linorder_less_split superseded by linorder_cases;
  2769 
  2770 * HOL/List: "nodups" renamed to "distinct";
  2771 
  2772 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2773 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2774   - Ex_def has changed, now need to use some_eq_ex
  2775 
  2776 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2777 in this (rare) case use:
  2778 
  2779   delSWrapper "split_all_tac"
  2780   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2781 
  2782 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2783 MAY FAIL;
  2784 
  2785 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2786 Isabelle's type classes, ^ on functions and relations has too general
  2787 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2788 necessary to attach explicit type constraints;
  2789 
  2790 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2791 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2792 renamed accordingly (eg "compI" -> "rel_compI").
  2793 
  2794 * HOL: syntax translations now work properly with numerals and records
  2795 expressions;
  2796 
  2797 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2798 of "lam" -- INCOMPATIBILITY;
  2799 
  2800 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2801 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2802 renamed "Product_Type.unit";
  2803 
  2804 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2805 
  2806 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2807 the "cases" method);
  2808 
  2809 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2810 Florian Kammller);
  2811 
  2812 * HOL/IMP: updated and converted to new-style theory format; several
  2813 parts turned into readable document, with proper Isar proof texts and
  2814 some explanations (by Gerwin Klein);
  2815 
  2816 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2817 
  2818 * HOL-Hyperreal is now a logic image;
  2819 
  2820 
  2821 *** HOLCF ***
  2822 
  2823 * Isar: consts/constdefs supports mixfix syntax for continuous
  2824 operations;
  2825 
  2826 * Isar: domain package adapted to new-style theory format, e.g. see
  2827 HOLCF/ex/Dnat.thy;
  2828 
  2829 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2830 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2831 lift.induct_tac, always use UU instead of Undef;
  2832 
  2833 * HOLCF/IMP: updated and converted to new-style theory;
  2834 
  2835 
  2836 *** ZF ***
  2837 
  2838 * Isar: proper integration of logic-specific tools and packages,
  2839 including theory commands '(co)inductive', '(co)datatype',
  2840 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2841 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2842 
  2843 * theory Main no longer includes AC; for the Axiom of Choice, base
  2844 your theory on Main_ZFC;
  2845 
  2846 * the integer library now covers quotients and remainders, with many
  2847 laws relating division to addition, multiplication, etc.;
  2848 
  2849 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2850 typeless version of the formalism;
  2851 
  2852 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2853 format;
  2854 
  2855 * ZF/Induct: new directory for examples of inductive definitions,
  2856 including theory Multiset for multiset orderings; converted to
  2857 new-style theory format;
  2858 
  2859 * ZF: many new theorems about lists, ordinals, etc.;
  2860 
  2861 
  2862 *** General ***
  2863 
  2864 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2865 variable proof controls level of detail: 0 = no proofs (only oracle
  2866 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2867 also ref manual for further ML interfaces;
  2868 
  2869 * Pure/axclass: removed obsolete ML interface
  2870 goal_subclass/goal_arity;
  2871 
  2872 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2873 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2874 separate tokens, so expressions involving minus need to be spaced
  2875 properly;
  2876 
  2877 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2878 rather than "infixl" or "infixr";
  2879 
  2880 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2881 sort constraint specifications in type inference; e.g. "x::_::foo"
  2882 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2883 type variable);
  2884 
  2885 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2886 control output of nested => (types); the default behavior is
  2887 "type_brackets";
  2888 
  2889 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2890 tokens into AST constants;
  2891 
  2892 * Pure/syntax: prefer later declarations of translations and print
  2893 translation functions; potential INCOMPATIBILITY: need to reverse
  2894 multiple declarations for same syntax element constant;
  2895 
  2896 * Pure/show_hyps reset by default (in accordance to existing Isar
  2897 practice);
  2898 
  2899 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2900 addSafter;
  2901 
  2902 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2903 as well;
  2904 
  2905 * system: tested support for MacOS X; should be able to get Isabelle +
  2906 Proof General to work in a plain Terminal after installing Poly/ML
  2907 (e.g. from the Isabelle distribution area) and GNU bash alone
  2908 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2909 support requires further installations, e.g. from
  2910 http://fink.sourceforge.net/);
  2911 
  2912 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2913 
  2914 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2915 of 40 MB), cf. ML_OPTIONS;
  2916 
  2917 * system: Proof General keywords specification is now part of the
  2918 Isabelle distribution (see etc/isar-keywords.el);
  2919 
  2920 * system: support for persistent Proof General sessions (refrain from
  2921 outdating all loaded theories on startup); user may create writable
  2922 logic images like this: ``isabelle -q HOL Test'';
  2923 
  2924 * system: smart selection of Isabelle process versus Isabelle
  2925 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2926 run both "isabelle" and "Isabelle" even if file names are badly
  2927 damaged (executable inspects the case of the first letter of its own
  2928 name); added separate "isabelle-process" and "isabelle-interface";
  2929 
  2930 * system: refrain from any attempt at filtering input streams; no
  2931 longer support ``8bit'' encoding of old isabelle font, instead proper
  2932 iso-latin characters may now be used; the related isatools
  2933 "symbolinput" and "nonascii" have disappeared as well;
  2934 
  2935 * system: removed old "xterm" interface (the print modes "xterm" and
  2936 "xterm_color" are still available for direct use in a suitable
  2937 terminal);
  2938 
  2939 
  2940 
  2941 New in Isabelle99-2 (February 2001)
  2942 -----------------------------------
  2943 
  2944 *** Overview of INCOMPATIBILITIES ***
  2945 
  2946 * HOL: please note that theories in the Library and elsewhere often use the
  2947 new-style (Isar) format; to refer to their theorems in an ML script you must
  2948 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2949 
  2950 * HOL: inductive package no longer splits induction rule aggressively,
  2951 but only as far as specified by the introductions given; the old
  2952 format may be recovered via ML function complete_split_rule or attribute
  2953 'split_rule (complete)';
  2954 
  2955 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2956 gfp_Tarski to gfp_unfold;
  2957 
  2958 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2959 
  2960 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2961 relation); infix "^^" has been renamed "``"; infix "``" has been
  2962 renamed "`"; "univalent" has been renamed "single_valued";
  2963 
  2964 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2965 operation;
  2966 
  2967 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2968 
  2969 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2970 
  2971 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2972 consequence, it is no longer monotonic wrt. the local goal context
  2973 (which is now passed through the inductive cases);
  2974 
  2975 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2976 \<gg> to \<ggreater>;
  2977 
  2978 
  2979 *** Document preparation ***
  2980 
  2981 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2982 available: are "it" for near math-mode best-style output, "sl" for
  2983 slanted text style, and "tt" for plain type-writer; if no
  2984 \isabellestyle command is given, output is according to slanted
  2985 type-writer);
  2986 
  2987 * support sub/super scripts (for single symbols only), input syntax is
  2988 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2989 
  2990 * some more standard symbols; see Appendix A of the system manual for
  2991 the complete list of symbols defined in isabellesym.sty;
  2992 
  2993 * improved isabelle style files; more abstract symbol implementation
  2994 (should now use \isamath{...} and \isatext{...} in custom symbol
  2995 definitions);
  2996 
  2997 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2998 state; Note that presentation of goal states does not conform to
  2999 actual human-readable proof documents.  Please do not include goal
  3000 states into document output unless you really know what you are doing!
  3001 
  3002 * proper indentation of antiquoted output with proportional LaTeX
  3003 fonts;
  3004 
  3005 * no_document ML operator temporarily disables LaTeX document
  3006 generation;
  3007 
  3008 * isatool unsymbolize tunes sources for plain ASCII communication;
  3009 
  3010 
  3011 *** Isar ***
  3012 
  3013 * Pure: Isar now suffers initial goal statements to contain unbound
  3014 schematic variables (this does not conform to actual readable proof
  3015 documents, due to unpredictable outcome and non-compositional proof
  3016 checking); users who know what they are doing may use schematic goals
  3017 for Prolog-style synthesis of proven results;
  3018 
  3019 * Pure: assumption method (an implicit finishing) now handles actual
  3020 rules as well;
  3021 
  3022 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3023 initial goal, declare "that" only as Pure intro (only for single
  3024 steps); the "that" rule assumption may now be involved in implicit
  3025 finishing, thus ".." becomes a feasible for trivial obtains;
  3026 
  3027 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3028 instance proofs may be performed by "..";
  3029 
  3030 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3031 statements as well;
  3032 
  3033 * Pure: more robust selection of calculational rules;
  3034 
  3035 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3036 rule (as well as the assumption rule);
  3037 
  3038 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3039 lemmas, using the graph browser tool;
  3040 
  3041 * Pure: predict failure of "show" in interactive mode;
  3042 
  3043 * Pure: 'thms_containing' now takes actual terms as arguments;
  3044 
  3045 * HOL: improved method 'induct' --- now handles non-atomic goals
  3046 (potential INCOMPATIBILITY); tuned error handling;
  3047 
  3048 * HOL: cases and induct rules now provide explicit hints about the
  3049 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3050 any remaining facts are inserted into the goal verbatim;
  3051 
  3052 * HOL: local contexts (aka cases) may now contain term bindings as
  3053 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3054 the result to be shown in each case;
  3055 
  3056 * HOL: added 'recdef_tc' command;
  3057 
  3058 * isatool convert assists in eliminating legacy ML scripts;
  3059 
  3060 
  3061 *** HOL ***
  3062 
  3063 * HOL/Library: a collection of generic theories to be used together
  3064 with main HOL; the theory loader path already includes this directory
  3065 by default; the following existing theories have been moved here:
  3066 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3067 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3068 
  3069 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3070 modelling and verification task performed in Isabelle/HOL +
  3071 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3072 
  3073 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3074 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3075 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3076 'domain', this makes the theory consistent with mathematical
  3077 literature;
  3078 
  3079 * HOL basics: added overloaded operations "inverse" and "divide"
  3080 (infix "/"), syntax for generic "abs" operation, generic summation
  3081 operator \<Sum>;
  3082 
  3083 * HOL/typedef: simplified package, provide more useful rules (see also
  3084 HOL/subset.thy);
  3085 
  3086 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3087 now expressed as a proper nested rule (old-style tactic scripts may
  3088 require atomize_strip_tac to cope with non-atomic premises);
  3089 
  3090 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3091 to "split_conv" (old name still available for compatibility);
  3092 
  3093 * HOL: improved concrete syntax for strings (e.g. allows translation
  3094 rules with string literals);
  3095 
  3096 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3097  and Fleuriot's mechanization of analysis, including the transcendental
  3098  functions for the reals;
  3099 
  3100 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3101 
  3102 
  3103 *** CTT ***
  3104 
  3105 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3106 "lam" is displayed as TWO lambda-symbols
  3107 
  3108 * CTT: theory Main now available, containing everything (that is, Bool
  3109 and Arith);
  3110 
  3111 
  3112 *** General ***
  3113 
  3114 * Pure: the Simplifier has been implemented properly as a derived rule
  3115 outside of the actual kernel (at last!); the overall performance
  3116 penalty in practical applications is about 50%, while reliability of
  3117 the Isabelle inference kernel has been greatly improved;
  3118 
  3119 * print modes "brackets" and "no_brackets" control output of nested =>
  3120 (types) and ==> (props); the default behaviour is "brackets";
  3121 
  3122 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3123 as assumptions as well;
  3124 
  3125 * system: support Poly/ML 4.0;
  3126 
  3127 * system: isatool install handles KDE version 1 or 2;
  3128 
  3129 
  3130 
  3131 New in Isabelle99-1 (October 2000)
  3132 ----------------------------------
  3133 
  3134 *** Overview of INCOMPATIBILITIES ***
  3135 
  3136 * HOL: simplification of natural numbers is much changed; to partly
  3137 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3138 issue the following ML commands:
  3139 
  3140   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3141   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3142 
  3143 * HOL: simplification no longer dives into case-expressions; this is
  3144 controlled by "t.weak_case_cong" for each datatype t;
  3145 
  3146 * HOL: nat_less_induct renamed to less_induct;
  3147 
  3148 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3149 fixsome to patch .thy and .ML sources automatically;
  3150 
  3151   select_equality  -> some_equality
  3152   select_eq_Ex     -> some_eq_ex
  3153   selectI2EX       -> someI2_ex
  3154   selectI2         -> someI2
  3155   selectI          -> someI
  3156   select1_equality -> some1_equality
  3157   Eps_sym_eq       -> some_sym_eq_trivial
  3158   Eps_eq           -> some_eq_trivial
  3159 
  3160 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3161 
  3162 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3163 instead);
  3164 
  3165 * HOL: the recursion equations generated by 'recdef' are now called
  3166 f.simps instead of f.rules;
  3167 
  3168 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3169 
  3170 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3171 sometimes be needed;
  3172 
  3173 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3174 
  3175 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3176 
  3177 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3178 product is now "<*>" instead of "Times"; the lexicographic product is
  3179 now "<*lex*>" instead of "**";
  3180 
  3181 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3182 of main HOL, but was unused); better use HOL's datatype package;
  3183 
  3184 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3185 the old syntax may be recovered as follows:
  3186 
  3187   syntax (symbols)
  3188     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3189       (infixl "\\<oplus>" 100)
  3190 
  3191 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3192 
  3193 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3194 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3195 internally;
  3196 
  3197 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3198 changed from A/r to A//r;
  3199 
  3200 * ZF: new treatment of arithmetic (nat & int) may break some old
  3201 proofs;
  3202 
  3203 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3204 rulify -> rule_format, elimify -> elim_format, ...);
  3205 
  3206 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3207 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3208 should have to change intro!! to intro? only); replaced "delrule" by
  3209 "rule del";
  3210 
  3211 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3212 
  3213 * Provers: strengthened force_tac by using new first_best_tac;
  3214 
  3215 * LaTeX document preparation: several changes of isabelle.sty (see
  3216 lib/texinputs);
  3217 
  3218 
  3219 *** Document preparation ***
  3220 
  3221 * formal comments (text blocks etc.) in new-style theories may now
  3222 contain antiquotations of thm/prop/term/typ/text to be presented
  3223 according to latex print mode; concrete syntax is like this:
  3224 @{term[show_types] "f(x) = a + x"};
  3225 
  3226 * isatool mkdir provides easy setup of Isabelle session directories,
  3227 including proper document sources;
  3228 
  3229 * generated LaTeX sources are now deleted after successful run
  3230 (isatool document -c); may retain a copy somewhere else via -D option
  3231 of isatool usedir;
  3232 
  3233 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3234 style files, achieving self-contained LaTeX sources and simplifying
  3235 LaTeX debugging;
  3236 
  3237 * old-style theories now produce (crude) LaTeX output as well;
  3238 
  3239 * browser info session directories are now self-contained (may be put
  3240 on WWW server seperately); improved graphs of nested sessions; removed
  3241 graph for 'all sessions';
  3242 
  3243 * several improvements in isabelle style files; \isabellestyle{it}
  3244 produces fake math mode output; \isamarkupheader is now \section by
  3245 default; see lib/texinputs/isabelle.sty etc.;
  3246 
  3247 
  3248 *** Isar ***
  3249 
  3250 * Isar/Pure: local results and corresponding term bindings are now
  3251 subject to Hindley-Milner polymorphism (similar to ML); this
  3252 accommodates incremental type-inference very nicely;
  3253 
  3254 * Isar/Pure: new derived language element 'obtain' supports
  3255 generalized existence reasoning;
  3256 
  3257 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3258 support accumulation of results, without applying any rules yet;
  3259 useful to collect intermediate results without explicit name
  3260 references, and for use with transitivity rules with more than 2
  3261 premises;
  3262 
  3263 * Isar/Pure: scalable support for case-analysis type proofs: new
  3264 'case' language element refers to local contexts symbolically, as
  3265 produced by certain proof methods; internally, case names are attached
  3266 to theorems as "tags";
  3267 
  3268 * Isar/Pure: theory command 'hide' removes declarations from
  3269 class/type/const name spaces;
  3270 
  3271 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3272 indicate potential overloading;
  3273 
  3274 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3275 
  3276 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3277 "{a,b,c}" instead of {a,b,c};
  3278 
  3279 * Isar/Pure now provides its own version of intro/elim/dest
  3280 attributes; useful for building new logics, but beware of confusion
  3281 with the version in Provers/classical;
  3282 
  3283 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3284 case name 'antecedent';
  3285 
  3286 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3287 to the current context is now done automatically);
  3288 
  3289 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3290 for definining proof methods in ML;
  3291 
  3292 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3293 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3294 most cases, one should have to change intro!! to intro? only);
  3295 replaced "delrule" by "rule del";
  3296 
  3297 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3298 'symmetric' attribute (the latter supercedes [RS sym]);
  3299 
  3300 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3301 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3302 well (including splits);
  3303 
  3304 * Isar/Provers: Simplifier and Classical methods now support all kind
  3305 of modifiers used in the past, including 'cong', 'iff', etc.
  3306 
  3307 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3308 of Simplifier and Classical reasoner);
  3309 
  3310 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3311 now support named cases; major packages (inductive, datatype, primrec,
  3312 recdef) support case names and properly name parameters;
  3313 
  3314 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3315 monotonicity conditions are extracted to be proven at end of
  3316 calculations;
  3317 
  3318 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3319 method anyway;
  3320 
  3321 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3322 split_if split_if_asm; datatype package provides theorems foo.splits =
  3323 foo.split foo.split_asm for each datatype;
  3324 
  3325 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3326 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3327 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3328 use "(cases (simplified))" method in proper proof texts);
  3329 
  3330 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3331 
  3332 * Isar: names of theorems etc. may be natural numbers as well;
  3333 
  3334 * Isar: 'pr' command: optional arguments for goals_limit and
  3335 ProofContext.prems_limit; no longer prints theory contexts, but only
  3336 proof states;
  3337 
  3338 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3339 additional print modes to be specified; e.g. "pr(latex)" will print
  3340 proof state according to the Isabelle LaTeX style;
  3341 
  3342 * Isar: improved support for emulating tactic scripts, including proof
  3343 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3344 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3345 (for HOL datatypes);
  3346 
  3347 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3348 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3349 'proof method scripts' have to be in depth-first order;
  3350 
  3351 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3352 
  3353 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3354 should instead use individual commands for printing items
  3355 (print_commands, print_methods etc.);
  3356 
  3357 * Isar: added 'nothing' --- the empty list of theorems;
  3358 
  3359 
  3360 *** HOL ***
  3361 
  3362 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3363 corresponding virtual machine and a specification of its bytecode
  3364 verifier and a lightweight bytecode verifier, including proofs of
  3365 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3366 Cornelia Pusch (see also the homepage of project Bali at
  3367 http://isabelle.in.tum.de/Bali/);
  3368 
  3369 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3370 Clemens Ballarin;
  3371 
  3372 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3373 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3374 Rasmussen;
  3375 
  3376 * HOL/Lattice: fundamental concepts of lattice theory and order
  3377 structures, including duals, properties of bounds versus algebraic
  3378 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3379 Theorem for complete lattices etc.; may also serve as a demonstration
  3380 for abstract algebraic reasoning using axiomatic type classes, and
  3381 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3382 
  3383 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3384 von Oheimb;
  3385 
  3386 * HOL/IMPP: extension of IMP with local variables and mutually
  3387 recursive procedures, by David von Oheimb;
  3388 
  3389 * HOL/Lambda: converted into new-style theory and document;
  3390 
  3391 * HOL/ex/Multiquote: example of multiple nested quotations and
  3392 anti-quotations -- basically a generalized version of de-Bruijn
  3393 representation; very useful in avoiding lifting of operations;
  3394 
  3395 * HOL/record: added general record equality rule to simpset; fixed
  3396 select-update simplification procedure to handle extended records as
  3397 well; admit "r" as field name;
  3398 
  3399 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3400 other numeric types and also as the identity of groups, rings, etc.;
  3401 
  3402 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3403 Types nat and int belong to this axclass;
  3404 
  3405 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3406    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3407    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3408   two terms #m*u and #n*u are replaced by #(m+n)*u
  3409     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3410   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3411     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3412 
  3413 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3414 powerful prover for predicate logic but knows nothing of clasets; see
  3415 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3416 
  3417 * HOL: new version of "case_tac" subsumes both boolean case split and
  3418 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3419 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3420 
  3421 * HOL: simplification no longer dives into case-expressions: only the
  3422 selector expression is simplified, but not the remaining arms; to
  3423 enable full simplification of case-expressions for datatype t, you may
  3424 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3425 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3426 
  3427 * HOL/recdef: the recursion equations generated by 'recdef' for
  3428 function 'f' are now called f.simps instead of f.rules; if all
  3429 termination conditions are proved automatically, these simplification
  3430 rules are added to the simpset, as in primrec; rules may be named
  3431 individually as well, resulting in a separate list of theorems for
  3432 each equation;
  3433 
  3434 * HOL/While is a new theory that provides a while-combinator. It
  3435 permits the definition of tail-recursive functions without the
  3436 provision of a termination measure. The latter is necessary once the
  3437 invariant proof rule for while is applied.
  3438 
  3439 * HOL: new (overloaded) notation for the set of elements below/above
  3440 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3441 
  3442 * HOL: theorems impI, allI, ballI bound as "strip";
  3443 
  3444 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3445 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3446 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3447 
  3448 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3449 
  3450 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3451 main HOL, but was unused);
  3452 
  3453 * HOL: fewer consts declared as global (e.g. have to refer to
  3454 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3455 
  3456 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3457 in case of overlap with user translations (e.g. judgements over
  3458 tuples); (note that the underlying logical represenation is still
  3459 bogus);
  3460 
  3461 
  3462 *** ZF ***
  3463 
  3464 * ZF: simplification automatically cancels common terms in arithmetic
  3465 expressions over nat and int;
  3466 
  3467 * ZF: new treatment of nat to minimize type-checking: all operators
  3468 coerce their operands to a natural number using the function natify,
  3469 making the algebraic laws unconditional;
  3470 
  3471 * ZF: as above, for int: operators coerce their operands to an integer
  3472 using the function intify;
  3473 
  3474 * ZF: the integer library now contains many of the usual laws for the
  3475 orderings, including $<=, and monotonicity laws for $+ and $*;
  3476 
  3477 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3478 simplification;
  3479 
  3480 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3481 to the simplifier and classical reasoner simultaneously;
  3482 
  3483 
  3484 *** General ***
  3485 
  3486 * Provers: blast_tac now handles actual object-logic rules as
  3487 assumptions; note that auto_tac uses blast_tac internally as well;
  3488 
  3489 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3490 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3491 
  3492 * Provers: delrules now handles destruct rules as well (no longer need
  3493 explicit make_elim);
  3494 
  3495 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3496   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3497 use instead the strong form,
  3498   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3499 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3500 from destruct-rules;
  3501 
  3502 * Provers: Simplifier.easy_setup provides a fast path to basic
  3503 Simplifier setup for new object-logics;
  3504 
  3505 * Pure: AST translation rules no longer require constant head on LHS;
  3506 
  3507 * Pure: improved name spaces: ambiguous output is qualified; support
  3508 for hiding of names;
  3509 
  3510 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3511 XSYMBOL_HOME; no longer need to do manual configuration in most
  3512 situations;
  3513 
  3514 * system: compression of ML heaps images may now be controlled via -c
  3515 option of isabelle and isatool usedir (currently only observed by
  3516 Poly/ML);
  3517 
  3518 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3519 useful for remote X11);
  3520 
  3521 * system: provide TAGS file for Isabelle sources;
  3522 
  3523 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3524 order;
  3525 
  3526 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3527 timing flag supersedes proof_timing and Toplevel.trace;
  3528 
  3529 * ML: new combinators |>> and |>>> for incremental transformations
  3530 with secondary results (e.g. certain theory extensions):
  3531 
  3532 * ML: PureThy.add_defs gets additional argument to indicate potential
  3533 overloading (usually false);
  3534 
  3535 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3536 results;
  3537 
  3538 
  3539 
  3540 New in Isabelle99 (October 1999)
  3541 --------------------------------
  3542 
  3543 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3544 
  3545 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3546 are no longer simplified.  (This allows the simplifier to unfold recursive
  3547 functional programs.)  To restore the old behaviour, declare
  3548 
  3549     Delcongs [if_weak_cong];
  3550 
  3551 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3552 complement;
  3553 
  3554 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3555 
  3556 * HOL/datatype: mutual_induct_tac no longer exists --
  3557   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3558 
  3559 * HOL/typedef: fixed type inference for representing set; type
  3560 arguments now have to occur explicitly on the rhs as type constraints;
  3561 
  3562 * ZF: The con_defs part of an inductive definition may no longer refer
  3563 to constants declared in the same theory;
  3564 
  3565 * HOL, ZF: the function mk_cases, generated by the inductive
  3566 definition package, has lost an argument.  To simplify its result, it
  3567 uses the default simpset instead of a supplied list of theorems.
  3568 
  3569 * HOL/List: the constructors of type list are now Nil and Cons;
  3570 
  3571 * Simplifier: the type of the infix ML functions
  3572         setSSolver addSSolver setSolver addSolver
  3573 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3574 for packaging solvers. A solver is created via
  3575         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3576 where the string argument is only a comment.
  3577 
  3578 
  3579 *** Proof tools ***
  3580 
  3581 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3582 decision procedure for linear arithmetic. Currently it is used for
  3583 types `nat', `int', and `real' in HOL (see below); it can, should and
  3584 will be instantiated for other types and logics as well.
  3585 
  3586 * The simplifier now accepts rewrite rules with flexible heads, eg
  3587      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3588   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3589   matching.
  3590 
  3591 
  3592 *** General ***
  3593 
  3594 * New Isabelle/Isar subsystem provides an alternative to traditional
  3595 tactical theorem proving; together with the ProofGeneral/isar user
  3596 interface it offers an interactive environment for developing human
  3597 readable proof documents (Isar == Intelligible semi-automated
  3598 reasoning); for further information see isatool doc isar-ref,
  3599 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3600 
  3601 * improved and simplified presentation of theories: better HTML markup
  3602 (including colors), graph views in several sizes; isatool usedir now
  3603 provides a proper interface for user theories (via -P option); actual
  3604 document preparation based on (PDF)LaTeX is available as well (for
  3605 new-style theories only); see isatool doc system for more information;
  3606 
  3607 * native support for Proof General, both for classic Isabelle and
  3608 Isabelle/Isar;
  3609 
  3610 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3611 using the graph browser tool;
  3612 
  3613 * Isabelle manuals now also available as PDF;
  3614 
  3615 * theory loader rewritten from scratch (may not be fully
  3616 bug-compatible); old loadpath variable has been replaced by show_path,
  3617 add_path, del_path, reset_path functions; new operations such as
  3618 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3619 isatool doc ref);
  3620 
  3621 * improved isatool install: option -k creates KDE application icon,
  3622 option -p DIR installs standalone binaries;
  3623 
  3624 * added ML_PLATFORM setting (useful for cross-platform installations);
  3625 more robust handling of platform specific ML images for SML/NJ;
  3626 
  3627 * the settings environment is now statically scoped, i.e. it is never
  3628 created again in sub-processes invoked from isabelle, isatool, or
  3629 Isabelle;
  3630 
  3631 * path element specification '~~' refers to '$ISABELLE_HOME';
  3632 
  3633 * in locales, the "assumes" and "defines" parts may be omitted if
  3634 empty;
  3635 
  3636 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3637 long arrows);
  3638 
  3639 * new print_mode "HTML";
  3640 
  3641 * new flag show_tags controls display of tags of theorems (which are
  3642 basically just comments that may be attached by some tools);
  3643 
  3644 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3645 mode and goal output format:
  3646 
  3647 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3648 244c244
  3649 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3650 ---
  3651 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3652 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3653 181c181
  3654 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3655 ---
  3656 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3657 
  3658 * function bind_thms stores lists of theorems (cf. bind_thm);
  3659 
  3660 * new shorthand tactics ftac, eatac, datac, fatac;
  3661 
  3662 * qed (and friends) now accept "" as result name; in that case the
  3663 theorem is not stored, but proper checks and presentation of the
  3664 result still apply;
  3665 
  3666 * theorem database now also indexes constants "Trueprop", "all",
  3667 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3668 
  3669 
  3670 *** HOL ***
  3671 
  3672 ** HOL arithmetic **
  3673 
  3674 * There are now decision procedures for linear arithmetic over nat and
  3675 int:
  3676 
  3677 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3678 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3679 are treated as atomic; subformulae not involving type `nat' or `int'
  3680 are ignored; quantified subformulae are ignored unless they are
  3681 positive universal or negative existential. The tactic has to be
  3682 invoked by hand and can be a little bit slow. In particular, the
  3683 running time is exponential in the number of occurrences of `min' and
  3684 `max', and `-' on `nat'.
  3685 
  3686 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3687 (negated) (in)equalities among the premises and the conclusion into
  3688 account (i.e. no compound formulae) and does not know about `min' and
  3689 `max', and `-' on `nat'. It is fast and is used automatically by the
  3690 simplifier.
  3691 
  3692 NB: At the moment, these decision procedures do not cope with mixed
  3693 nat/int formulae where the two parts interact, such as `m < n ==>
  3694 int(m) < int(n)'.
  3695 
  3696 * HOL/Numeral provides a generic theory of numerals (encoded
  3697 efficiently as bit strings); setup for types nat/int/real is in place;
  3698 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3699 int, existing theories and proof scripts may require a few additional
  3700 type constraints;
  3701 
  3702 * integer division and remainder can now be performed on constant
  3703 arguments;
  3704 
  3705 * many properties of integer multiplication, division and remainder
  3706 are now available;
  3707 
  3708 * An interface to the Stanford Validity Checker (SVC) is available through the
  3709 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3710 are proved automatically.  SVC must be installed separately, and its results
  3711 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3712 invocation of the underlying oracle).  For SVC see
  3713   http://verify.stanford.edu/SVC
  3714 
  3715 * IsaMakefile: the HOL-Real target now builds an actual image;
  3716 
  3717 
  3718 ** HOL misc **
  3719 
  3720 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3721 (in Isabelle/Isar) -- by Gertrud Bauer;
  3722 
  3723 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3724 analysis for assembly languages with subtypes;
  3725 
  3726 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3727 -- avoids syntactic ambiguities and treats state, transition, and
  3728 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3729 changed syntax and (many) tactics;
  3730 
  3731 * HOL/inductive: Now also handles more general introduction rules such
  3732   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3733   theorems are now maintained within the theory (maintained via the
  3734   "mono" attribute);
  3735 
  3736 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3737   (using function types) such as
  3738 
  3739   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3740 
  3741 * HOL/record: record_simproc (part of the default simpset) takes care
  3742 of selectors applied to updated records; record_split_tac is no longer
  3743 part of the default claset; update_defs may now be removed from the
  3744 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3745 
  3746   claset_ref () := claset() addSWrapper record_split_wrapper;
  3747   Delsimprocs [record_simproc]
  3748 
  3749 * HOL/typedef: fixed type inference for representing set; type
  3750 arguments now have to occur explicitly on the rhs as type constraints;
  3751 
  3752 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3753 names rather than an ML expression;
  3754 
  3755 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3756 supplied later.  Program schemes can be defined, such as
  3757     "While B C s = (if B s then While B C (C s) else s)"
  3758 where the well-founded relation can be chosen after B and C have been given.
  3759 
  3760 * HOL/List: the constructors of type list are now Nil and Cons;
  3761 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3762 course, ML tools referring to List.list.op # etc. have to be adapted;
  3763 
  3764 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3765 disabled by default; run isabelle with option -m HOL to get back to
  3766 the original Gordon/HOL-style output;
  3767 
  3768 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3769 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3770 
  3771 * HOL basic syntax simplified (more orthogonal): all variants of
  3772 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3773 Eps operator is provided as well: "SOME x. P[x]";
  3774 
  3775 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3776 
  3777 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3778 thus available for user theories;
  3779 
  3780 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3781 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3782 time;
  3783 
  3784 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3785 several times and then mp;
  3786 
  3787 
  3788 *** LK ***
  3789 
  3790 * the notation <<...>> is now available as a notation for sequences of
  3791 formulas;
  3792 
  3793 * the simplifier is now installed
  3794 
  3795 * the axiom system has been generalized (thanks to Soren Heilmann)
  3796 
  3797 * the classical reasoner now has a default rule database
  3798 
  3799 
  3800 *** ZF ***
  3801 
  3802 * new primrec section allows primitive recursive functions to be given
  3803 directly (as in HOL) over datatypes and the natural numbers;
  3804 
  3805 * new tactics induct_tac and exhaust_tac for induction (or case
  3806 analysis) over datatypes and the natural numbers;
  3807 
  3808 * the datatype declaration of type T now defines the recursor T_rec;
  3809 
  3810 * simplification automatically does freeness reasoning for datatype
  3811 constructors;
  3812 
  3813 * automatic type-inference, with AddTCs command to insert new
  3814 type-checking rules;
  3815 
  3816 * datatype introduction rules are now added as Safe Introduction rules
  3817 to the claset;
  3818 
  3819 * the syntax "if P then x else y" is now available in addition to
  3820 if(P,x,y);
  3821 
  3822 
  3823 *** Internal programming interfaces ***
  3824 
  3825 * tuned simplifier trace output; new flag debug_simp;
  3826 
  3827 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3828 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3829 
  3830 * AxClass.axclass_tac lost the theory argument;
  3831 
  3832 * tuned current_goals_markers semantics: begin / end goal avoids
  3833 printing empty lines;
  3834 
  3835 * removed prs and prs_fn hook, which was broken because it did not
  3836 include \n in its semantics, forcing writeln to add one
  3837 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3838 string -> unit if you really want to output text without newline;
  3839 
  3840 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3841 plain output, interface builders may have to enable 'isabelle_font'
  3842 mode to get Isabelle font glyphs as before;
  3843 
  3844 * refined token_translation interface; INCOMPATIBILITY: output length
  3845 now of type real instead of int;
  3846 
  3847 * theory loader actions may be traced via new ThyInfo.add_hook
  3848 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3849 your own database of information attached to *whole* theories -- as
  3850 opposed to intra-theory data slots offered via TheoryDataFun;
  3851 
  3852 * proper handling of dangling sort hypotheses (at last!);
  3853 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3854 extra sort hypotheses that can be witnessed from the type signature;
  3855 the force_strip_shyps flag is gone, any remaining shyps are simply
  3856 left in the theorem (with a warning issued by strip_shyps_warning);
  3857 
  3858 
  3859 
  3860 New in Isabelle98-1 (October 1998)
  3861 ----------------------------------
  3862 
  3863 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3864 
  3865 * several changes of automated proof tools;
  3866 
  3867 * HOL: major changes to the inductive and datatype packages, including
  3868 some minor incompatibilities of theory syntax;
  3869 
  3870 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3871 called `inj_on';
  3872 
  3873 * HOL: removed duplicate thms in Arith:
  3874   less_imp_add_less  should be replaced by  trans_less_add1
  3875   le_imp_add_le      should be replaced by  trans_le_add1
  3876 
  3877 * HOL: unary minus is now overloaded (new type constraints may be
  3878 required);
  3879 
  3880 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3881 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3882 now taken as an integer constant.
  3883 
  3884 * Pure: ML function 'theory_of' renamed to 'theory';
  3885 
  3886 
  3887 *** Proof tools ***
  3888 
  3889 * Simplifier:
  3890   1. Asm_full_simp_tac is now more aggressive.
  3891      1. It will sometimes reorient premises if that increases their power to
  3892         simplify.
  3893      2. It does no longer proceed strictly from left to right but may also
  3894         rotate premises to achieve further simplification.
  3895      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3896      old Asm_full_simp_tac in that it does not rotate premises.
  3897   2. The simplifier now knows a little bit about nat-arithmetic.
  3898 
  3899 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3900 allows for selected deletion of wrappers, by introduction of names for
  3901 wrapper functionals.  This implies that addbefore, addSbefore,
  3902 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3903 and that adding two tactics with the same name overwrites the first
  3904 one (emitting a warning).
  3905   type wrapper = (int -> tactic) -> (int -> tactic)
  3906   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3907   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3908   delWrapper, delSWrapper: claset *  string            -> claset
  3909   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3910 
  3911 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3912 semantics; addbefore now affects only the unsafe part of step_tac
  3913 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3914 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3915 by Force_tac;
  3916 
  3917 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3918 compWrapper; added safe wrapper (and access functions for it);
  3919 
  3920 * HOL/split_all_tac is now much faster and fails if there is nothing
  3921 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3922 and the names of the automatically generated variables have changed.
  3923 split_all_tac has moved within claset() from unsafe wrappers to safe
  3924 wrappers, which means that !!-bound variables are split much more
  3925 aggressively, and safe_tac and clarify_tac now split such variables.
  3926 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3927 Note: the same holds for record_split_tac, which does the job of
  3928 split_all_tac for record fields.
  3929 
  3930 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3931 permanently to the default simpset using Addsplits just like
  3932 Addsimps. They can be removed via Delsplits just like
  3933 Delsimps. Lower-case versions are also available.
  3934 
  3935 * HOL/Simplifier: The rule split_if is now part of the default
  3936 simpset. This means that the simplifier will eliminate all occurrences
  3937 of if-then-else in the conclusion of a goal. To prevent this, you can
  3938 either remove split_if completely from the default simpset by
  3939 `Delsplits [split_if]' or remove it in a specific call of the
  3940 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3941 other case splitting rules to/from the default simpset: every datatype
  3942 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3943 t is the name of the datatype).
  3944 
  3945 * Classical reasoner / Simplifier combination: new force_tac (and
  3946 derivatives Force_tac, force) combines rewriting and classical
  3947 reasoning (and whatever other tools) similarly to auto_tac, but is
  3948 aimed to solve the given subgoal completely.
  3949 
  3950 
  3951 *** General ***
  3952 
  3953 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3954 and `goalw': the theory is no longer needed as an explicit argument -
  3955 the current theory context is used; assumptions are no longer returned
  3956 at the ML-level unless one of them starts with ==> or !!; it is
  3957 recommended to convert to these new commands using isatool fixgoal
  3958 (backup your sources first!);
  3959 
  3960 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3961 the current theory context, and 'theory' to lookup stored theories;
  3962 
  3963 * new theory section 'locale' for declaring constants, assumptions and
  3964 definitions that have local scope;
  3965 
  3966 * new theory section 'nonterminals' for purely syntactic types;
  3967 
  3968 * new theory section 'setup' for generic ML setup functions
  3969 (e.g. package initialization);
  3970 
  3971 * the distribution now includes Isabelle icons: see
  3972 lib/logo/isabelle-{small,tiny}.xpm;
  3973 
  3974 * isatool install - install binaries with absolute references to
  3975 ISABELLE_HOME/bin;
  3976 
  3977 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3978 
  3979 * print mode 'emacs' reserved for Isamode;
  3980 
  3981 * support multiple print (ast) translations per constant name;
  3982 
  3983 * theorems involving oracles are now printed with a suffixed [!];
  3984 
  3985 
  3986 *** HOL ***
  3987 
  3988 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3989 
  3990 * HOL/inductive package reorganized and improved: now supports mutual
  3991 definitions such as
  3992 
  3993   inductive EVEN ODD
  3994     intrs
  3995       null "0 : EVEN"
  3996       oddI "n : EVEN ==> Suc n : ODD"
  3997       evenI "n : ODD ==> Suc n : EVEN"
  3998 
  3999 new theorem list "elims" contains an elimination rule for each of the
  4000 recursive sets; inductive definitions now handle disjunctive premises
  4001 correctly (also ZF);
  4002 
  4003 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4004 "mutual_induct" no longer exists - the induction rule is always
  4005 contained in "induct";
  4006 
  4007 
  4008 * HOL/datatype package re-implemented and greatly improved: now
  4009 supports mutually recursive datatypes such as
  4010 
  4011   datatype
  4012     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4013             | SUM ('a aexp) ('a aexp)
  4014             | DIFF ('a aexp) ('a aexp)
  4015             | NUM 'a
  4016   and
  4017     'a bexp = LESS ('a aexp) ('a aexp)
  4018             | AND ('a bexp) ('a bexp)
  4019             | OR ('a bexp) ('a bexp)
  4020 
  4021 as well as indirectly recursive datatypes such as
  4022 
  4023   datatype
  4024     ('a, 'b) term = Var 'a
  4025                   | App 'b ((('a, 'b) term) list)
  4026 
  4027 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4028 induction on mutually / indirectly recursive datatypes.
  4029 
  4030 Primrec equations are now stored in theory and can be accessed via
  4031 <function_name>.simps.
  4032 
  4033 INCOMPATIBILITIES:
  4034 
  4035   - Theories using datatypes must now have theory Datatype as an
  4036     ancestor.
  4037   - The specific <typename>.induct_tac no longer exists - use the
  4038     generic induct_tac instead.
  4039   - natE has been renamed to nat.exhaust - use exhaust_tac
  4040     instead of res_inst_tac ... natE. Note that the variable
  4041     names in nat.exhaust differ from the names in natE, this
  4042     may cause some "fragile" proofs to fail.
  4043   - The theorems split_<typename>_case and split_<typename>_case_asm
  4044     have been renamed to <typename>.split and <typename>.split_asm.
  4045   - Since default sorts of type variables are now handled correctly,
  4046     some datatype definitions may have to be annotated with explicit
  4047     sort constraints.
  4048   - Primrec definitions no longer require function name and type
  4049     of recursive argument.
  4050 
  4051 Consider using isatool fixdatatype to adapt your theories and proof
  4052 scripts to the new package (backup your sources first!).
  4053 
  4054 
  4055 * HOL/record package: considerably improved implementation; now
  4056 includes concrete syntax for record types, terms, updates; theorems
  4057 for surjective pairing and splitting !!-bound record variables; proof
  4058 support is as follows:
  4059 
  4060   1) standard conversions (selectors or updates applied to record
  4061 constructor terms) are part of the standard simpset;
  4062 
  4063   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4064 made part of standard simpset and claset via addIffs;
  4065 
  4066   3) a tactic for record field splitting (record_split_tac) is part of
  4067 the standard claset (addSWrapper);
  4068 
  4069 To get a better idea about these rules you may retrieve them via
  4070 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4071 the name of your record type.
  4072 
  4073 The split tactic 3) conceptually simplifies by the following rule:
  4074 
  4075   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4076 
  4077 Thus any record variable that is bound by meta-all will automatically
  4078 blow up into some record constructor term, consequently the
  4079 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4080 solve record problems automatically.
  4081 
  4082 
  4083 * reorganized the main HOL image: HOL/Integ and String loaded by
  4084 default; theory Main includes everything;
  4085 
  4086 * automatic simplification of integer sums and comparisons, using cancellation;
  4087 
  4088 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4089 
  4090 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4091 
  4092 * many new identities for unions, intersections, set difference, etc.;
  4093 
  4094 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4095 called split_if, split_split, split_sum_case and split_nat_case (to go
  4096 with add/delsplits);
  4097 
  4098 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4099 (?x::unit) = (); this is made part of the default simpset, which COULD
  4100 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4101 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4102 unit_abs_eta_conv is added in order to counter the effect of
  4103 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4104 %u.f();
  4105 
  4106 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4107 makes more sense);
  4108 
  4109 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4110   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4111   disjointness reasoning but breaking a few old proofs.
  4112 
  4113 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4114 to 'converse' from 'inverse' (for compatibility with ZF and some
  4115 literature);
  4116 
  4117 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4118 the well-founded relation;
  4119 
  4120 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4121     Compl A.  The "Compl" syntax remains available as input syntax for this
  4122     release ONLY.
  4123 
  4124 * HOL/Update: new theory of function updates:
  4125     f(a:=b) == %x. if x=a then b else f x
  4126 may also be iterated as in f(a:=b,c:=d,...);
  4127 
  4128 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4129 
  4130 * HOL/List:
  4131   - new function list_update written xs[i:=v] that updates the i-th
  4132     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4133   - new function `upt' written [i..j(] which generates the list
  4134     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4135     bound write [i..j], which is a shorthand for [i..j+1(].
  4136   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4137 
  4138 * HOL/Arith:
  4139   - removed 'pred' (predecessor) function;
  4140   - generalized some theorems about n-1;
  4141   - many new laws about "div" and "mod";
  4142   - new laws about greatest common divisors (see theory ex/Primes);
  4143 
  4144 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4145 instead of "inverse";
  4146 
  4147 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4148   of the multiset ordering;
  4149 
  4150 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4151   (not included by default);
  4152 
  4153 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4154 
  4155 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4156   programs, i.e. different program variables may have different types.
  4157 
  4158 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4159   [previously, this check worked only if the rewrite rule was unconditional]
  4160   Now rew can involve either definitions or equalities (either == or =).
  4161 
  4162 
  4163 *** ZF ***
  4164 
  4165 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4166   only the theorems proved on ZF.ML;
  4167 
  4168 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4169   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4170   disjointness reasoning but breaking a few old proofs.
  4171 
  4172 * ZF/Update: new theory of function updates
  4173     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4174   may also be iterated as in f(a:=b,c:=d,...);
  4175 
  4176 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4177 
  4178 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4179   [previously, this check worked only if the rewrite rule was unconditional]
  4180   Now rew can involve either definitions or equalities (either == or =).
  4181 
  4182 * case_tac provided for compatibility with HOL
  4183     (like the old excluded_middle_tac, but with subgoals swapped)
  4184 
  4185 
  4186 *** Internal programming interfaces ***
  4187 
  4188 * Pure: several new basic modules made available for general use, see
  4189 also src/Pure/README;
  4190 
  4191 * improved the theory data mechanism to support encapsulation (data
  4192 kind name replaced by private Object.kind, acting as authorization
  4193 key); new type-safe user interface via functor TheoryDataFun; generic
  4194 print_data function becomes basically useless;
  4195 
  4196 * removed global_names compatibility flag -- all theory declarations
  4197 are qualified by default;
  4198 
  4199 * module Pure/Syntax now offers quote / antiquote translation
  4200 functions (useful for Hoare logic etc. with implicit dependencies);
  4201 see HOL/ex/Antiquote for an example use;
  4202 
  4203 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4204 cterm -> thm;
  4205 
  4206 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4207 subgoal;
  4208 
  4209 * Display.print_goals function moved to Locale.print_goals;
  4210 
  4211 * standard print function for goals supports current_goals_markers
  4212 variable for marking begin of proof, end of proof, start of goal; the
  4213 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4214 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4215 for example;
  4216 
  4217 
  4218 
  4219 New in Isabelle98 (January 1998)
  4220 --------------------------------
  4221 
  4222 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4223 
  4224 * changed lexical syntax of terms / types: dots made part of long
  4225 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4226 
  4227 * simpset (and claset) reference variable replaced by functions
  4228 simpset / simpset_ref;
  4229 
  4230 * no longer supports theory aliases (via merge) and non-trivial
  4231 implicit merge of thms' signatures;
  4232 
  4233 * most internal names of constants changed due to qualified names;
  4234 
  4235 * changed Pure/Sequence interface (see Pure/seq.ML);
  4236 
  4237 
  4238 *** General Changes ***
  4239 
  4240 * hierachically structured name spaces (for consts, types, axms, thms
  4241 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4242 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4243 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4244 long_names for fully qualified output names; NOTE: ML programs
  4245 (special tactics, packages etc.) referring to internal names may have
  4246 to be adapted to cope with fully qualified names; in case of severe
  4247 backward campatibility problems try setting 'global_names' at compile
  4248 time to have enrything declared within a flat name space; one may also
  4249 fine tune name declarations in theories via the 'global' and 'local'
  4250 section;
  4251 
  4252 * reimplemented the implicit simpset and claset using the new anytype
  4253 data filed in signatures; references simpset:simpset ref etc. are
  4254 replaced by functions simpset:unit->simpset and
  4255 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4256 to patch your ML files accordingly;
  4257 
  4258 * HTML output now includes theory graph data for display with Java
  4259 applet or isatool browser; data generated automatically via isatool
  4260 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4261 
  4262 * defs may now be conditional; improved rewrite_goals_tac to handle
  4263 conditional equations;
  4264 
  4265 * defs now admits additional type arguments, using TYPE('a) syntax;
  4266 
  4267 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4268 creates a new theory node; implicit merge of thms' signatures is
  4269 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4270 transfer:theory->thm->thm in (rare) cases;
  4271 
  4272 * improved handling of draft signatures / theories; draft thms (and
  4273 ctyps, cterms) are automatically promoted to real ones;
  4274 
  4275 * slightly changed interfaces for oracles: admit many per theory, named
  4276 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4277 
  4278 * print_goals: optional output of const types (set show_consts and
  4279 show_types);
  4280 
  4281 * improved output of warnings (###) and errors (***);
  4282 
  4283 * subgoal_tac displays a warning if the new subgoal has type variables;
  4284 
  4285 * removed old README and Makefiles;
  4286 
  4287 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4288 
  4289 * removed obsolete init_pps and init_database;
  4290 
  4291 * deleted the obsolete tactical STATE, which was declared by
  4292     fun STATE tacfun st = tacfun st st;
  4293 
  4294 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4295 (which abbreviates $HOME);
  4296 
  4297 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4298 use isatool fixseq to adapt your ML programs (this works for fully
  4299 qualified references to the Sequence structure only!);
  4300 
  4301 * use_thy no longer requires writable current directory; it always
  4302 reloads .ML *and* .thy file, if either one is out of date;
  4303 
  4304 
  4305 *** Classical Reasoner ***
  4306 
  4307 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4308 tactics that use classical reasoning to simplify a subgoal without
  4309 splitting it into several subgoals;
  4310 
  4311 * Safe_tac: like safe_tac but uses the default claset;
  4312 
  4313 
  4314 *** Simplifier ***
  4315 
  4316 * added simplification meta rules:
  4317     (asm_)(full_)simplify: simpset -> thm -> thm;
  4318 
  4319 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4320 logics (again);
  4321 
  4322 * added prems argument to simplification procedures;
  4323 
  4324 * HOL, FOL, ZF: added infix function `addsplits':
  4325   instead of `<simpset> setloop (split_tac <thms>)'
  4326   you can simply write `<simpset> addsplits <thms>'
  4327 
  4328 
  4329 *** Syntax ***
  4330 
  4331 * TYPE('a) syntax for type reflection terms;
  4332 
  4333 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4334 
  4335 * pretty printer: changed order of mixfix annotation preference (again!);
  4336 
  4337 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4338 
  4339 
  4340 *** HOL ***
  4341 
  4342 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4343   with `addloop' of the simplifier to faciliate case splitting in premises.
  4344 
  4345 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4346 
  4347 * HOL/Auth: new protocol proofs including some for the Internet
  4348   protocol TLS;
  4349 
  4350 * HOL/Map: new theory of `maps' a la VDM;
  4351 
  4352 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4353 cancelling out common nat summands from =, <, <= (in)equalities, or
  4354 differences; simplification procedures nat_cancel_factor for
  4355 cancelling common factor from =, <, <= (in)equalities over natural
  4356 sums; nat_cancel contains both kinds of procedures, it is installed by
  4357 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4358 
  4359 * HOL/simplifier: terms of the form
  4360   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4361   are rewritten to
  4362   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4363   and those of the form
  4364   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4365   are rewritten to
  4366   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4367 
  4368 * HOL/datatype
  4369   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4370 
  4371   P(t_case f1 ... fn x) =
  4372      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4373         ...
  4374        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4375      )
  4376 
  4377   and a theorem `split_t_case_asm' of the form
  4378 
  4379   P(t_case f1 ... fn x) =
  4380     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4381         ...
  4382        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4383      )
  4384   which can be added to a simpset via `addsplits'. The existing theorems
  4385   expand_list_case and expand_option_case have been renamed to
  4386   split_list_case and split_option_case.
  4387 
  4388 * HOL/Arithmetic:
  4389   - `pred n' is automatically converted to `n-1'.
  4390     Users are strongly encouraged not to use `pred' any longer,
  4391     because it will disappear altogether at some point.
  4392   - Users are strongly encouraged to write "0 < n" rather than
  4393     "n ~= 0". Theorems and proof tools have been modified towards this
  4394     `standard'.
  4395 
  4396 * HOL/Lists:
  4397   the function "set_of_list" has been renamed "set" (and its theorems too);
  4398   the function "nth" now takes its arguments in the reverse order and
  4399   has acquired the infix notation "!" as in "xs!n".
  4400 
  4401 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4402 
  4403 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4404   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4405 
  4406 * HOL/record: extensible records with schematic structural subtyping
  4407 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4408 still lacks various theorems and concrete record syntax;
  4409 
  4410 
  4411 *** HOLCF ***
  4412 
  4413 * removed "axioms" and "generated by" sections;
  4414 
  4415 * replaced "ops" section by extended "consts" section, which is capable of
  4416   handling the continuous function space "->" directly;
  4417 
  4418 * domain package:
  4419   . proves theorems immediately and stores them in the theory,
  4420   . creates hierachical name space,
  4421   . now uses normal mixfix annotations (instead of cinfix...),
  4422   . minor changes to some names and values (for consistency),
  4423   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4424   . separator between mutual domain defs: changed "," to "and",
  4425   . improved handling of sort constraints;  now they have to
  4426     appear on the left-hand side of the equations only;
  4427 
  4428 * fixed LAM <x,y,zs>.b syntax;
  4429 
  4430 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4431 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4432 
  4433 
  4434 *** FOL and ZF ***
  4435 
  4436 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4437   with `addloop' of the simplifier to faciliate case splitting in premises.
  4438 
  4439 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4440 in HOL, they strip ALL and --> from proved theorems;
  4441 
  4442 
  4443 
  4444 New in Isabelle94-8 (May 1997)
  4445 ------------------------------
  4446 
  4447 *** General Changes ***
  4448 
  4449 * new utilities to build / run / maintain Isabelle etc. (in parts
  4450 still somewhat experimental); old Makefiles etc. still functional;
  4451 
  4452 * new 'Isabelle System Manual';
  4453 
  4454 * INSTALL text, together with ./configure and ./build scripts;
  4455 
  4456 * reimplemented type inference for greater efficiency, better error
  4457 messages and clean internal interface;
  4458 
  4459 * prlim command for dealing with lots of subgoals (an easier way of
  4460 setting goals_limit);
  4461 
  4462 
  4463 *** Syntax ***
  4464 
  4465 * supports alternative (named) syntax tables (parser and pretty
  4466 printer); internal interface is provided by add_modesyntax(_i);
  4467 
  4468 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4469 be used in conjunction with the Isabelle symbol font; uses the
  4470 "symbols" syntax table;
  4471 
  4472 * added token_translation interface (may translate name tokens in
  4473 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4474 the current print_mode); IMPORTANT: user print translation functions
  4475 are responsible for marking newly introduced bounds
  4476 (Syntax.mark_boundT);
  4477 
  4478 * token translations for modes "xterm" and "xterm_color" that display
  4479 names in bold, underline etc. or colors (which requires a color
  4480 version of xterm);
  4481 
  4482 * infixes may now be declared with names independent of their syntax;
  4483 
  4484 * added typed_print_translation (like print_translation, but may
  4485 access type of constant);
  4486 
  4487 
  4488 *** Classical Reasoner ***
  4489 
  4490 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4491 some limitations.  Blast_tac...
  4492   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4493   + ignores elimination rules that don't have the correct format
  4494         (the conclusion MUST be a formula variable)
  4495   + ignores types, which can make HOL proofs fail
  4496   + rules must not require higher-order unification, e.g. apply_type in ZF
  4497     [message "Function Var's argument not a bound variable" relates to this]
  4498   + its proof strategy is more general but can actually be slower
  4499 
  4500 * substitution with equality assumptions no longer permutes other
  4501 assumptions;
  4502 
  4503 * minor changes in semantics of addafter (now called addaltern); renamed
  4504 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4505 (and access functions for it);
  4506 
  4507 * improved combination of classical reasoner and simplifier:
  4508   + functions for handling clasimpsets
  4509   + improvement of addss: now the simplifier is called _after_ the
  4510     safe steps.
  4511   + safe variant of addss called addSss: uses safe simplifications
  4512     _during_ the safe steps. It is more complete as it allows multiple
  4513     instantiations of unknowns (e.g. with slow_tac).
  4514 
  4515 *** Simplifier ***
  4516 
  4517 * added interface for simplification procedures (functions that
  4518 produce *proven* rewrite rules on the fly, depending on current
  4519 redex);
  4520 
  4521 * ordering on terms as parameter (used for ordered rewriting);
  4522 
  4523 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4524 
  4525 * the solver is now split into a safe and an unsafe part.
  4526 This should be invisible for the normal user, except that the
  4527 functions setsolver and addsolver have been renamed to setSolver and
  4528 addSolver; added safe_asm_full_simp_tac;
  4529 
  4530 
  4531 *** HOL ***
  4532 
  4533 * a generic induction tactic `induct_tac' which works for all datatypes and
  4534 also for type `nat';
  4535 
  4536 * a generic case distinction tactic `exhaust_tac' which works for all
  4537 datatypes and also for type `nat';
  4538 
  4539 * each datatype comes with a function `size';
  4540 
  4541 * patterns in case expressions allow tuple patterns as arguments to
  4542 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4543 
  4544 * primrec now also works with type nat;
  4545 
  4546 * recdef: a new declaration form, allows general recursive functions to be
  4547 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4548 
  4549 * the constant for negation has been renamed from "not" to "Not" to
  4550 harmonize with FOL, ZF, LK, etc.;
  4551 
  4552 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4553 infinite lists;
  4554 
  4555 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4556 
  4557 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4558 problems in commutative rings, using axiomatic type classes for + and *;
  4559 
  4560 * more examples in HOL/MiniML and HOL/Auth;
  4561 
  4562 * more default rewrite rules for quantifiers, union/intersection;
  4563 
  4564 * a new constant `arbitrary == @x.False';
  4565 
  4566 * HOLCF/IOA replaces old HOL/IOA;
  4567 
  4568 * HOLCF changes: derived all rules and arities
  4569   + axiomatic type classes instead of classes
  4570   + typedef instead of faking type definitions
  4571   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4572   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4573   + eliminated the types void, one, tr
  4574   + use unit lift and bool lift (with translations) instead of one and tr
  4575   + eliminated blift from Lift3.thy (use Def instead of blift)
  4576   all eliminated rules are derived as theorems --> no visible changes ;
  4577 
  4578 
  4579 *** ZF ***
  4580 
  4581 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4582 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4583 as ZF_cs addSIs [equalityI];
  4584 
  4585 
  4586 
  4587 New in Isabelle94-7 (November 96)
  4588 ---------------------------------
  4589 
  4590 * allowing negative levels (as offsets) in prlev and choplev;
  4591 
  4592 * super-linear speedup for large simplifications;
  4593 
  4594 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4595 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4596 FAIL); can suppress it using the command Delsimps (ex_simps @
  4597 all_simps); De Morgan laws are also now included, by default;
  4598 
  4599 * improved printing of ==>  :  ~:
  4600 
  4601 * new object-logic "Sequents" adds linear logic, while replacing LK
  4602 and Modal (thanks to Sara Kalvala);
  4603 
  4604 * HOL/Auth: correctness proofs for authentication protocols;
  4605 
  4606 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4607 examples on HOL/Auth);
  4608 
  4609 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4610 the rewriter and classical reasoner simultaneously;
  4611 
  4612 * function uresult no longer returns theorems in "standard" format;
  4613 regain previous version by: val uresult = standard o uresult;
  4614 
  4615 
  4616 
  4617 New in Isabelle94-6
  4618 -------------------
  4619 
  4620 * oracles -- these establish an interface between Isabelle and trusted
  4621 external reasoners, which may deliver results as theorems;
  4622 
  4623 * proof objects (in particular record all uses of oracles);
  4624 
  4625 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4626 
  4627 * "constdefs" section in theory files;
  4628 
  4629 * "primrec" section (HOL) no longer requires names;
  4630 
  4631 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4632 
  4633 
  4634 
  4635 New in Isabelle94-5
  4636 -------------------
  4637 
  4638 * reduced space requirements;
  4639 
  4640 * automatic HTML generation from theories;
  4641 
  4642 * theory files no longer require "..." (quotes) around most types;
  4643 
  4644 * new examples, including two proofs of the Church-Rosser theorem;
  4645 
  4646 * non-curried (1994) version of HOL is no longer distributed;
  4647 
  4648 
  4649 
  4650 New in Isabelle94-4
  4651 -------------------
  4652 
  4653 * greatly reduced space requirements;
  4654 
  4655 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4656 
  4657 * searchable theorem database (see the section "Retrieving theorems" on
  4658 page 8 of the Reference Manual);
  4659 
  4660 * new examples, including Grabczewski's monumental case study of the
  4661 Axiom of Choice;
  4662 
  4663 * The previous version of HOL renamed to Old_HOL;
  4664 
  4665 * The new version of HOL (previously called CHOL) uses a curried syntax
  4666 for functions.  Application looks like f a b instead of f(a,b);
  4667 
  4668 * Mutually recursive inductive definitions finally work in HOL;
  4669 
  4670 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4671 translates to the operator "split";
  4672 
  4673 
  4674 
  4675 New in Isabelle94-3
  4676 -------------------
  4677 
  4678 * new infix operator, addss, allowing the classical reasoner to
  4679 perform simplification at each step of its search.  Example:
  4680         fast_tac (cs addss ss)
  4681 
  4682 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4683 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4684 look like (a,b) instead of <a,b>;
  4685 
  4686 * PLEASE NOTE: CHOL will eventually replace HOL!
  4687 
  4688 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4689 It translates to the operator "split".  A new theory of integers is available;
  4690 
  4691 * In ZF, integer numerals now denote two's-complement binary integers.
  4692 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4693 
  4694 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4695 of the Axiom of Choice;
  4696 
  4697 
  4698 
  4699 New in Isabelle94-2
  4700 -------------------
  4701 
  4702 * Significantly faster resolution;
  4703 
  4704 * the different sections in a .thy file can now be mixed and repeated
  4705 freely;
  4706 
  4707 * Database of theorems for FOL, HOL and ZF.  New
  4708 commands including qed, qed_goal and bind_thm store theorems in the database.
  4709 
  4710 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4711 a given theory (thms_of), or find out what theory a theorem was proved in
  4712 (theory_of_thm);
  4713 
  4714 * Bugs fixed in the inductive definition and datatype packages;
  4715 
  4716 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4717 and HOL_dup_cs obsolete;
  4718 
  4719 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4720 have been removed;
  4721 
  4722 * Simpler definition of function space in ZF;
  4723 
  4724 * new results about cardinal and ordinal arithmetic in ZF;
  4725 
  4726 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4727 types;
  4728 
  4729 
  4730 $Id$