NEWS
author wenzelm
Tue May 08 15:01:28 2007 +0200 (2007-05-08)
changeset 22863 e1d3fa78b8e1
parent 22848 f65a76867179
child 22871 9ffb43b19ec6
permissions -rw-r--r--
tuned context data;
     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", "fun", "help",
    23 "if") are now keywords.  INCOMPATIBILITY, use double quotes.
    24 
    25 * Legacy goal package: reduced interface to the bare minimum required
    26 to keep existing proof scripts running.  Most other user-level
    27 functions are now part of the OldGoals structure, which is *not* open
    28 by default (consider isatool expandshort before open OldGoals).
    29 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    30 these tend to cause confusion about the actual goal (!) context being
    31 used here, which is not necessarily the same as the_context().
    32 
    33 * Command 'find_theorems': support "*" wildcard in "name:" criterion.
    34 
    35 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    36 by default, which means that "prems" (and also "fixed variables") are
    37 suppressed from proof state output.  Note that the ProofGeneral
    38 settings mechanism allows to change and save options persistently, but
    39 older versions of Isabelle will fail to start up if a negative prems
    40 limit is imposed.
    41 
    42 * Local theory targets may be specified by non-nested blocks of
    43 ``context/locale/class ... begin'' followed by ``end''.  The body may
    44 contain definitions, theorems etc., including any derived mechanism
    45 that has been implemented on top of these primitives.  This concept
    46 generalizes the existing ``theorem (in ...)'' towards more versatility
    47 and scalability.
    48 
    49 * Proof General interface: proper undo of final 'end' command;
    50 discontinued Isabelle/classic mode (ML proof scripts).
    51 
    52 
    53 *** Document preparation ***
    54 
    55 * Added antiquotation @{theory name} which prints the given name,
    56 after checking that it refers to a valid ancestor theory in the
    57 current context.
    58 
    59 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    60 check the given source text as ML type/structure, printing verbatim.
    61 
    62 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    63 "c args == rhs" given in the current context.  (Any number of
    64 arguments may be given on the LHS.)
    65 
    66 
    67 
    68 *** Pure ***
    69 
    70 * code generator: 
    71   - Isar "definition"s and primitive instance definitions are added explicitly
    72     to the table of defining equations
    73   - primitive definitions are not used as defining equations by default any longer
    74   - defining equations are now definitly restricted to meta "==" and object
    75         equality "="
    76   - HOL theories have been adopted accordingly
    77 
    78 * class_package.ML offers a combination of axclasses and locales to
    79 achieve Haskell-like type classes in Isabelle. See
    80 HOL/ex/Classpackage.thy for examples.
    81 
    82 * Yet another code generator framework allows to generate executable
    83 code for ML and Haskell (including "class"es). A short usage sketch:
    84 
    85     internal compilation:
    86         code_gen <list of constants (term syntax)> (SML #)
    87     writing SML code to a file:
    88         code_gen <list of constants (term syntax)> (SML <filename>)
    89     writing OCaml code to a file:
    90         code_gen <list of constants (term syntax)> (OCaml <filename>)
    91     writing Haskell code to a bunch of files:
    92         code_gen <list of constants (term syntax)> (Haskell <filename>)
    93 
    94 Reasonable default setup of framework in HOL/Main.
    95 
    96 Theorem attributs for selecting and transforming function equations theorems:
    97 
    98     [code fun]:        select a theorem as function equation for a specific constant
    99     [code fun del]:    deselect a theorem as function equation for a specific constant
   100     [code inline]:     select an equation theorem for unfolding (inlining) in place
   101     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   102 
   103 User-defined serializations (target in {SML, OCaml, Haskell}):
   104 
   105     code_const <and-list of constants (term syntax)>
   106       {(target) <and-list of const target syntax>}+
   107 
   108     code_type <and-list of type constructors>
   109       {(target) <and-list of type target syntax>}+
   110 
   111     code_instance <and-list of instances>
   112       {(target)}+
   113         where instance ::= <type constructor> :: <class>
   114 
   115     code_class <and_list of classes>
   116       {(target) <and-list of class target syntax>}+
   117         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   118 
   119 code_instance and code_class only apply to target Haskell.
   120 
   121 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   122 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   123 
   124 * Command 'no_translations' removes translation rules from theory
   125 syntax.
   126 
   127 * Overloaded definitions are now actually checked for acyclic
   128 dependencies.  The overloading scheme is slightly more general than
   129 that of Haskell98, although Isabelle does not demand an exact
   130 correspondence to type class and instance declarations.
   131 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   132 exotic versions of overloading -- at the discretion of the user!
   133 
   134 Polymorphic constants are represented via type arguments, i.e. the
   135 instantiation that matches an instance against the most general
   136 declaration given in the signature.  For example, with the declaration
   137 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   138 as c(nat).  Overloading is essentially simultaneous structural
   139 recursion over such type arguments.  Incomplete specification patterns
   140 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   141 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   142 Command 'print_theory' outputs the normalized system of recursive
   143 equations, see section "definitions".
   144 
   145 * Isar: improper proof element 'guess' is like 'obtain', but derives
   146 the obtained context from the course of reasoning!  For example:
   147 
   148   assume "EX x y. A x & B y"   -- "any previous fact"
   149   then guess x and y by clarify
   150 
   151 This technique is potentially adventurous, depending on the facts and
   152 proof tools being involved here.
   153 
   154 * Isar: known facts from the proof context may be specified as literal
   155 propositions, using ASCII back-quote syntax.  This works wherever
   156 named facts used to be allowed so far, in proof commands, proof
   157 methods, attributes etc.  Literal facts are retrieved from the context
   158 according to unification of type and term parameters.  For example,
   159 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   160 theorems in the current context, then these are valid literal facts:
   161 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   162 
   163 There is also a proof method "fact" which does the same composition
   164 for explicit goal states, e.g. the following proof texts coincide with
   165 certain special cases of literal facts:
   166 
   167   have "A" by fact                 ==  note `A`
   168   have "A ==> B" by fact           ==  note `A ==> B`
   169   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   170   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   171 
   172 * Isar: ":" (colon) is no longer a symbolic identifier character in
   173 outer syntax.  Thus symbolic identifiers may be used without
   174 additional white space in declarations like this: ``assume *: A''.
   175 
   176 * Isar: 'print_facts' prints all local facts of the current context,
   177 both named and unnamed ones.
   178 
   179 * Isar: 'def' now admits simultaneous definitions, e.g.:
   180 
   181   def x == "t" and y == "u"
   182 
   183 * Isar: added command 'unfolding', which is structurally similar to
   184 'using', but affects both the goal state and facts by unfolding given
   185 rewrite rules.  Thus many occurrences of the 'unfold' method or
   186 'unfolded' attribute may be replaced by first-class proof text.
   187 
   188 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   189 and command 'unfolding' now all support object-level equalities
   190 (potentially conditional).  The underlying notion of rewrite rule is
   191 analogous to the 'rule_format' attribute, but *not* that of the
   192 Simplifier (which is usually more generous).
   193 
   194 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   195 method expression within a sandbox consisting of the first N
   196 sub-goals, which need to exist.  For example, ``simp_all [3]''
   197 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   198 simplifies all new goals that emerge from applying rule foo to the
   199 originally first one.
   200 
   201 * Isar: schematic goals are no longer restricted to higher-order
   202 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   203 expected.
   204 
   205 * Isar: the conclusion of a long theorem statement is now either
   206 'shows' (a simultaneous conjunction, as before), or 'obtains'
   207 (essentially a disjunction of cases with local parameters and
   208 assumptions).  The latter allows to express general elimination rules
   209 adequately; in this notation common elimination rules look like this:
   210 
   211   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   212     assumes "EX x. P x"
   213     obtains x where "P x"
   214 
   215   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   216     assumes "A & B"
   217     obtains A and B
   218 
   219   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   220     assumes "A | B"
   221     obtains
   222       A
   223     | B
   224 
   225 The subsequent classical rules even refer to the formal "thesis"
   226 explicitly:
   227 
   228   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   229     obtains "~ thesis"
   230 
   231   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   232     obtains "thesis ==> something"
   233 
   234 The actual proof of an 'obtains' statement is analogous to that of the
   235 Isar proof element 'obtain', only that there may be several cases.
   236 Optional case names may be specified in parentheses; these will be
   237 available both in the present proof and as annotations in the
   238 resulting rule, for later use with the 'cases' method (cf. attribute
   239 case_names).
   240 
   241 * Isar: the assumptions of a long theorem statement are available as
   242 "assms" fact in the proof context.  This is more appropriate than the
   243 (historical) "prems", which refers to all assumptions of the current
   244 context, including those from the target locale, proof body etc.
   245 
   246 * Isar: 'print_statement' prints theorems from the current theory or
   247 proof context in long statement form, according to the syntax of a
   248 top-level lemma.
   249 
   250 * Isar: 'obtain' takes an optional case name for the local context
   251 introduction rule (default "that").
   252 
   253 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   254 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   255 to occur.
   256 
   257 * Pure: syntax "CONST name" produces a fully internalized constant
   258 according to the current context.  This is particularly useful for
   259 syntax translations that should refer to internal constant
   260 representations independently of name spaces.
   261 
   262 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   263 instead of "FOO ". This allows multiple binder declarations to coexist
   264 in the same context.  INCOMPATIBILITY.
   265 
   266 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   267 primitive that also works in a locale context (both for constants and
   268 fixed variables).  Type declaration and internal syntactic
   269 representation of given constants retrieved from the context.
   270 
   271 * Isar/locales: new derived specification elements 'axiomatization',
   272 'definition', 'abbreviation', which support type-inference, admit
   273 object-level specifications (equality, equivalence).  See also the
   274 isar-ref manual.  Examples:
   275 
   276   axiomatization
   277     eq  (infix "===" 50) where
   278     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   279 
   280   definition "f x y = x + y + 1"
   281   definition g where "g x = f x x"
   282 
   283   abbreviation
   284     neq  (infix "=!=" 50) where
   285     "x =!= y == ~ (x === y)"
   286 
   287 These specifications may be also used in a locale context.  Then the
   288 constants being introduced depend on certain fixed parameters, and the
   289 constant name is qualified by the locale base name.  An internal
   290 abbreviation takes care for convenient input and output, making the
   291 parameters implicit and using the original short name.  See also
   292 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   293 entities from a monomorphic theory.
   294 
   295 Presently, abbreviations are only available 'in' a target locale, but
   296 not inherited by general import expressions.  Also note that
   297 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   298 'translations' in common applications.
   299 
   300 Concrete syntax is attached to specified constants in internal form,
   301 independently of name spaces.  The parse tree representation is
   302 slightly different -- use 'notation' instead of raw 'syntax', and
   303 'translations' with explicit "CONST" markup to accommodate this.
   304 
   305 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   306 the current context.  Print mode "no_abbrevs" prevents inversion of
   307 abbreviations on output.
   308 
   309 * Isar/locales: improved parameter handling:
   310 - use of locales "var" and "struct" no longer necessary;
   311 - parameter renamings are no longer required to be injective.
   312   This enables, for example, to define a locale for endomorphisms thus:
   313   locale endom = homom mult mult h.
   314 
   315 * Isar/locales: changed the way locales with predicates are defined.
   316 Instead of accumulating the specification, the imported expression is
   317 now an interpretation.  INCOMPATIBILITY: different normal form of
   318 locale expressions.  In particular, in interpretations of locales with
   319 predicates, goals repesenting already interpreted fragments are not
   320 removed automatically.  Use methods `intro_locales' and
   321 `unfold_locales'; see below.
   322 
   323 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   324 provide backward reasoning on locales predicates.  The methods are
   325 aware of interpretations and discharge corresponding goals.
   326 `intro_locales' is less aggressive then `unfold_locales' and does not
   327 unfold predicates to assumptions.
   328 
   329 * Isar/locales: the order in which locale fragments are accumulated
   330 has changed.  This enables to override declarations from fragments due
   331 to interpretations -- for example, unwanted simp rules.
   332 
   333 * Provers/induct: improved internal context management to support
   334 local fixes and defines on-the-fly.  Thus explicit meta-level
   335 connectives !! and ==> are rarely required anymore in inductive goals
   336 (using object-logic connectives for this purpose has been long
   337 obsolete anyway).  The subsequent proof patterns illustrate advanced
   338 techniques of natural induction; general datatypes and inductive sets
   339 work analogously (see also src/HOL/Lambda for realistic examples).
   340 
   341 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   342 parameters:
   343 
   344   lemma
   345     fixes n :: nat and x :: 'a
   346     assumes a: "A n x"
   347     shows "P n x"
   348     using a                     -- {* make induct insert fact a *}
   349   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   350     case 0
   351     show ?case sorry
   352   next
   353     case (Suc n)
   354     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   355     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   356     show ?case sorry
   357   qed
   358 
   359 (2) This is how to perform induction over ``expressions of a certain
   360 form'', using a locally defined inductive parameter n == "a x"
   361 together with strengthening (the latter is usually required to get
   362 sufficiently flexible induction hypotheses):
   363 
   364   lemma
   365     fixes a :: "'a => nat"
   366     assumes a: "A (a x)"
   367     shows "P (a x)"
   368     using a
   369   proof (induct n == "a x" arbitrary: x)
   370     ...
   371 
   372 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   373 particular technique.
   374 
   375 (3) This is how to perform existential reasoning ('obtains' or
   376 'obtain') by induction, while avoiding explicit object-logic
   377 encodings:
   378 
   379   lemma
   380     fixes n :: nat
   381     obtains x :: 'a where "P n x" and "Q n x"
   382   proof (induct n arbitrary: thesis)
   383     case 0
   384     obtain x where "P 0 x" and "Q 0 x" sorry
   385     then show thesis by (rule 0)
   386   next
   387     case (Suc n)
   388     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   389     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   390     then show thesis by (rule Suc.prems)
   391   qed
   392 
   393 Here the 'arbitrary: thesis' specification essentially modifies the
   394 scope of the formal thesis parameter, in order to the get the whole
   395 existence statement through the induction as expected.
   396 
   397 * Provers/induct: mutual induction rules are now specified as a list
   398 of rule sharing the same induction cases.  HOL packages usually
   399 provide foo_bar.inducts for mutually defined items foo and bar
   400 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   401 specify mutual induction rules differently, i.e. like this:
   402 
   403   (induct rule: foo_bar.inducts)
   404   (induct set: foo bar)
   405   (induct type: foo bar)
   406 
   407 The ML function ProjectRule.projections turns old-style rules into the
   408 new format.
   409 
   410 * Provers/induct: improved handling of simultaneous goals.  Instead of
   411 introducing object-level conjunction, the statement is now split into
   412 several conclusions, while the corresponding symbolic cases are
   413 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   414 explicitly.  For example:
   415 
   416   lemma
   417     fixes n :: nat
   418     shows "P n" and "Q n"
   419   proof (induct n)
   420     case 0 case 1
   421     show "P 0" sorry
   422   next
   423     case 0 case 2
   424     show "Q 0" sorry
   425   next
   426     case (Suc n) case 1
   427     note `P n` and `Q n`
   428     show "P (Suc n)" sorry
   429   next
   430     case (Suc n) case 2
   431     note `P n` and `Q n`
   432     show "Q (Suc n)" sorry
   433   qed
   434 
   435 The split into subcases may be deferred as follows -- this is
   436 particularly relevant for goal statements with local premises.
   437 
   438   lemma
   439     fixes n :: nat
   440     shows "A n ==> P n" and "B n ==> Q n"
   441   proof (induct n)
   442     case 0
   443     {
   444       case 1
   445       note `A 0`
   446       show "P 0" sorry
   447     next
   448       case 2
   449       note `B 0`
   450       show "Q 0" sorry
   451     }
   452   next
   453     case (Suc n)
   454     note `A n ==> P n` and `B n ==> Q n`
   455     {
   456       case 1
   457       note `A (Suc n)`
   458       show "P (Suc n)" sorry
   459     next
   460       case 2
   461       note `B (Suc n)`
   462       show "Q (Suc n)" sorry
   463     }
   464   qed
   465 
   466 If simultaneous goals are to be used with mutual rules, the statement
   467 needs to be structured carefully as a two-level conjunction, using
   468 lists of propositions separated by 'and':
   469 
   470   lemma
   471     shows "a : A ==> P1 a"
   472           "a : A ==> P2 a"
   473       and "b : B ==> Q1 b"
   474           "b : B ==> Q2 b"
   475           "b : B ==> Q3 b"
   476   proof (induct set: A B)
   477 
   478 * Provers/induct: support coinduction as well.  See
   479 src/HOL/Library/Coinductive_List.thy for various examples.
   480 
   481 * Attribute "symmetric" produces result with standardized schematic
   482 variables (index 0).  Potential INCOMPATIBILITY.
   483 
   484 * Simplifier: by default the simplifier trace only shows top level
   485 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   486 default. Thus there is less danger of being flooded by the trace. The
   487 trace indicates where parts have been suppressed.
   488   
   489 * Provers/classical: removed obsolete classical version of elim_format
   490 attribute; classical elim/dest rules are now treated uniformly when
   491 manipulating the claset.
   492 
   493 * Provers/classical: stricter checks to ensure that supplied intro,
   494 dest and elim rules are well-formed; dest and elim rules must have at
   495 least one premise.
   496 
   497 * Provers/classical: attributes dest/elim/intro take an optional
   498 weight argument for the rule (just as the Pure versions).  Weights are
   499 ignored by automated tools, but determine the search order of single
   500 rule steps.
   501 
   502 * Syntax: input syntax now supports dummy variable binding "%_. b",
   503 where the body does not mention the bound variable.  Note that dummy
   504 patterns implicitly depend on their context of bounds, which makes
   505 "{_. _}" match any set comprehension as expected.  Potential
   506 INCOMPATIBILITY -- parse translations need to cope with syntactic
   507 constant "_idtdummy" in the binding position.
   508 
   509 * Syntax: removed obsolete syntactic constant "_K" and its associated
   510 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   511 for example "A -> B" => "Pi A (%_. B)".
   512 
   513 * Pure: 'class_deps' command visualizes the subclass relation, using
   514 the graph browser tool.
   515 
   516 * Pure: 'print_theory' now suppresses entities with internal name
   517 (trailing "_") by default; use '!' option for full details.
   518 
   519 
   520 *** HOL ***
   521 
   522 * case expressions and primrec: missing cases now mapped to "undefined"
   523 instead of "arbitrary"
   524 
   525 * new constant "undefined" with axiom "undefined x = undefined"
   526 
   527 * new class "default" with associated constant "default"
   528 
   529 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   530     when generating code.
   531 
   532 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   533     when generating code.
   534 
   535 * Library/Commutative_Ring.thy: switched from recdef to function package;
   536     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   537 
   538 * Some steps towards more uniform lattice theory development in HOL.
   539 
   540     constants "meet" and "join" now named "inf" and "sup"
   541     constant "Meet" now named "Inf"
   542 
   543     classes "meet_semilorder" and "join_semilorder" now named
   544       "lower_semilattice" and "upper_semilattice"
   545     class "lorder" now named "lattice"
   546     class "comp_lat" now named "complete_lattice"
   547 
   548     Instantiation of lattice classes allows explicit definitions
   549     for "inf" and "sup" operations.
   550 
   551   INCOMPATIBILITY. Theorem renames:
   552 
   553     meet_left_le            ~> inf_le1
   554     meet_right_le           ~> inf_le2
   555     join_left_le            ~> sup_ge1
   556     join_right_le           ~> sup_ge2
   557     meet_join_le            ~> inf_sup_ord
   558     le_meetI                ~> le_infI
   559     join_leI                ~> le_supI
   560     le_meet                 ~> le_inf_iff
   561     le_join                 ~> ge_sup_conv
   562     meet_idempotent         ~> inf_idem
   563     join_idempotent         ~> sup_idem
   564     meet_comm               ~> inf_commute
   565     join_comm               ~> sup_commute
   566     meet_leI1               ~> le_infI1
   567     meet_leI2               ~> le_infI2
   568     le_joinI1               ~> le_supI1
   569     le_joinI2               ~> le_supI2
   570     meet_assoc              ~> inf_assoc
   571     join_assoc              ~> sup_assoc
   572     meet_left_comm          ~> inf_left_commute
   573     meet_left_idempotent    ~> inf_left_idem
   574     join_left_comm          ~> sup_left_commute
   575     join_left_idempotent    ~> sup_left_idem
   576     meet_aci                ~> inf_aci
   577     join_aci                ~> sup_aci
   578     le_def_meet             ~> le_iff_inf
   579     le_def_join             ~> le_iff_sup
   580     join_absorp2            ~> sup_absorb2
   581     join_absorp1            ~> sup_absorb1
   582     meet_absorp1            ~> inf_absorb1
   583     meet_absorp2            ~> inf_absorb2
   584     meet_join_absorp        ~> inf_sup_absorb
   585     join_meet_absorp        ~> sup_inf_absorb
   586     distrib_join_le         ~> distrib_sup_le
   587     distrib_meet_le         ~> distrib_inf_le
   588 
   589     add_meet_distrib_left   ~> add_inf_distrib_left
   590     add_join_distrib_left   ~> add_sup_distrib_left
   591     is_join_neg_meet        ~> is_join_neg_inf
   592     is_meet_neg_join        ~> is_meet_neg_sup
   593     add_meet_distrib_right  ~> add_inf_distrib_right
   594     add_join_distrib_right  ~> add_sup_distrib_right
   595     add_meet_join_distribs  ~> add_sup_inf_distribs
   596     join_eq_neg_meet        ~> sup_eq_neg_inf
   597     meet_eq_neg_join        ~> inf_eq_neg_sup
   598     add_eq_meet_join        ~> add_eq_inf_sup
   599     meet_0_imp_0            ~> inf_0_imp_0
   600     join_0_imp_0            ~> sup_0_imp_0
   601     meet_0_eq_0             ~> inf_0_eq_0
   602     join_0_eq_0             ~> sup_0_eq_0
   603     neg_meet_eq_join        ~> neg_inf_eq_sup
   604     neg_join_eq_meet        ~> neg_sup_eq_inf
   605     join_eq_if              ~> sup_eq_if
   606 
   607     mono_meet               ~> mono_inf
   608     mono_join               ~> mono_sup
   609     meet_bool_eq            ~> inf_bool_eq
   610     join_bool_eq            ~> sup_bool_eq
   611     meet_fun_eq             ~> inf_fun_eq
   612     join_fun_eq             ~> sup_fun_eq
   613     meet_set_eq             ~> inf_set_eq
   614     join_set_eq             ~> sup_set_eq
   615     meet1_iff               ~> inf1_iff
   616     meet2_iff               ~> inf2_iff
   617     meet1I                  ~> inf1I
   618     meet2I                  ~> inf2I
   619     meet1D1                 ~> inf1D1
   620     meet2D1                 ~> inf2D1
   621     meet1D2                 ~> inf1D2
   622     meet2D2                 ~> inf2D2
   623     meet1E                  ~> inf1E
   624     meet2E                  ~> inf2E
   625     join1_iff               ~> sup1_iff
   626     join2_iff               ~> sup2_iff
   627     join1I1                 ~> sup1I1
   628     join2I1                 ~> sup2I1
   629     join1I1                 ~> sup1I1
   630     join2I2                 ~> sup1I2
   631     join1CI                 ~> sup1CI
   632     join2CI                 ~> sup2CI
   633     join1E                  ~> sup1E
   634     join2E                  ~> sup2E
   635 
   636     is_meet_Meet            ~> is_meet_Inf
   637     Meet_bool_def           ~> Inf_bool_def
   638     Meet_fun_def            ~> Inf_fun_def
   639     Meet_greatest           ~> Inf_greatest
   640     Meet_lower              ~> Inf_lower
   641     Meet_set_def            ~> Inf_set_def
   642 
   643     listsp_meetI            ~> listsp_infI
   644     listsp_meet_eq          ~> listsp_inf_eq
   645 
   646     meet_min                ~> inf_min
   647     join_max                ~> sup_max
   648 
   649 * Classes "order" and "linorder": facts "refl", "trans" and
   650 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   651 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   652 
   653 * Classes "order" and "linorder": 
   654 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   655 proofs changed.
   656 
   657 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   658 INCOMPATIBILITY.
   659 
   660 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   661 INCOMPATIBILITY.
   662 
   663 * Added syntactic class "size"; overloaded constant "size" now has
   664 type "'a::size ==> bool"
   665 
   666 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   667 dvd" to "Divides.div", "Divides.mod" and "Divides.dvd". INCOMPATIBILITY.
   668 
   669 * Added method "lexicographic_order" automatically synthesizes
   670 termination relations as lexicographic combinations of size measures
   671 -- 'function' package.
   672 
   673 * HOL/records: generalised field-update to take a function on the
   674 field rather than the new value: r(|A := x|) is translated to A_update
   675 (K x) r The K-combinator that is internally used is called K_record.
   676 INCOMPATIBILITY: Usage of the plain update functions has to be
   677 adapted.
   678  
   679 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   680 0 * x = 0, which are required for a semiring.  Richer structures do
   681 not inherit from semiring_0 anymore, because this property is a
   682 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   683 semiring_0, there is more to prove, but this is mostly trivial.
   684 
   685 * axclass "recpower" was generalized to arbitrary monoids, not just
   686 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   687 commutativity or a semiring property, add the corresponding classes.
   688 
   689 * Unified locale partial_order with class definition (cf. theory
   690 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   691 
   692 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   693 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   694 Isar level, use abbreviations instead.
   695 
   696 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   697 rarely occuring name references (e.g. ``List.op mem.simps'') require
   698 renaming (e.g. ``List.memberl.simps'').
   699 
   700 * Renamed constants "0" to "HOL.zero" and "1" to "HOL.one".
   701 INCOMPATIBILITY.
   702 
   703 * Added theory Code_Generator providing class 'eq', allowing for code
   704 generation with polymorphic equality.
   705 
   706 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   707 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   708 significant changes for setting up numeral syntax for types:
   709 
   710   - new constants Numeral.pred and Numeral.succ instead
   711       of former Numeral.bin_pred and Numeral.bin_succ.
   712   - Use integer operations instead of bin_add, bin_mult and so on.
   713   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   714   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   715 
   716 See HOL/Integ/IntArith.thy for an example setup.
   717 
   718 * New top level command 'normal_form' computes the normal form of a
   719 term that may contain free variables. For example ``normal_form
   720 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   721 suitable for heavy-duty computations because the functions are
   722 compiled to ML first.
   723 
   724 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   725 25 like -->); output depends on the "iff" print_mode, the default is
   726 "A = B" (with priority 50).
   727 
   728 * Renamed constants in HOL.thy and Orderings.thy:
   729     op +   ~> HOL.plus
   730     op -   ~> HOL.minus
   731     uminus ~> HOL.uminus
   732     op *   ~> HOL.times
   733     op <   ~> Orderings.less
   734     op <=  ~> Orderings.less_eq
   735 
   736 Adaptions may be required in the following cases:
   737 
   738 a) User-defined constants using any of the names "plus", "minus", "times",
   739 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   740 may go wrong.
   741 INCOMPATIBILITY: use more specific names.
   742 
   743 b) Variables named "plus", "minus", "times", "less", "less_eq"
   744 INCOMPATIBILITY: use more specific names.
   745 
   746 c) Permutative equations (e.g. "a + b = b + a")
   747 Since the change of names also changes the order of terms, permutative
   748 rewrite rules may get applied in a different order. Experience shows that
   749 this is rarely the case (only two adaptions in the whole Isabelle
   750 distribution).
   751 INCOMPATIBILITY: rewrite proofs
   752 
   753 d) ML code directly refering to constant names
   754 This in general only affects hand-written proof tactics, simprocs and so on.
   755 INCOMPATIBILITY: grep your sourcecode and replace names.
   756 
   757 * Relations less (<) and less_eq (<=) are also available on type bool.
   758 Modified syntax to disallow nesting without explicit parentheses,
   759 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   760 
   761 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   762 
   763 * Relation composition operator "op O" now has precedence 75 and binds
   764 stronger than union and intersection. INCOMPATIBILITY.
   765 
   766 * The old set interval syntax "{m..n(}" (and relatives) has been
   767 removed.  Use "{m..<n}" (and relatives) instead.
   768 
   769 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   770 "t = s" to False (by simproc "neq_simproc").  For backward
   771 compatibility this can be disabled by ML "reset use_neq_simproc".
   772 
   773 * "m dvd n" where m and n are numbers is evaluated to True/False by
   774 simp.
   775 
   776 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   777 
   778 * Theorem setsum_mult renamed to setsum_right_distrib.
   779 
   780 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   781 ``rule'' method.
   782 
   783 * Reimplemented methods ``sat'' and ``satx'', with several
   784 improvements: goals no longer need to be stated as "<prems> ==>
   785 False", equivalences (i.e. "=" on type bool) are handled, variable
   786 names of the form "lit_<n>" are no longer reserved, significant
   787 speedup.
   788 
   789 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   790 zChaff is still supported as well.
   791 
   792 * 'inductive' and 'datatype': provide projections of mutual rules,
   793 bundled as foo_bar.inducts;
   794 
   795 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   796 Library.
   797 
   798 * Library: moved theory Accessible_Part to main HOL.
   799 
   800 * Library: added theory Coinductive_List of potentially infinite lists
   801 as greatest fixed-point.
   802 
   803 * Library: added theory AssocList which implements (finite) maps as
   804 association lists.
   805 
   806 * Added proof method ``evaluation'' for efficiently solving a goal
   807 (i.e. a boolean expression) by compiling it to ML. The goal is
   808 "proved" (via an oracle) if it evaluates to True.
   809 
   810 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   811 also when invoked by the simplifier.  This results in the simplifier
   812 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   813 fast_arith_split_limit to 0 to obtain the old behavior.
   814 
   815 * Support for hex (0x20) and binary (0b1001) numerals.
   816 
   817 * New method: reify eqs (t), where eqs are equations for an
   818 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   819 parameter, computes a term s::'b and a list xs::'a list and proves the
   820 theorem I xs s = t. This is also known as reification or quoting. The
   821 resulting theorem is applied to the subgoal to substitute t with I xs
   822 s.  If t is omitted, the subgoal itself is reified.
   823 
   824 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   825 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   826 where f is supposed to be a computable function (in the sense of code
   827 generattion). The method uses reify to compute s and xs as above then
   828 applies corr_thm and uses normalization by evaluation to "prove" f s =
   829 r and finally gets the theorem t = r, which is again applied to the
   830 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   831 
   832 * Reflection: Automatic refification now handels binding, an example
   833 is available in HOL/ex/ReflectionEx.thy
   834 
   835 
   836 *** HOL-Algebra ***
   837 
   838 * Formalisation of ideals and the quotient construction over rings.
   839 
   840 * Order and lattice theory no longer based on records.
   841 INCOMPATIBILITY.
   842 
   843 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   844 greatest_closed.  INCOMPATIBILITY.
   845 
   846 * Method algebra is now set up via an attribute.  For examples see
   847 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   848 of algebraic structures.
   849 
   850 * Renamed theory CRing to Ring.
   851 
   852 
   853 *** HOL-Complex ***
   854 
   855 * Theory Real: new method ferrack implements quantifier elimination
   856 for linear arithmetic over the reals. The quantifier elimination
   857 feature is used only for decision, for compatibility with arith. This
   858 means a goal is either solved or left unchanged, no simplification.
   859 
   860 * Real: New axiomatic classes formalize real normed vector spaces and
   861 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   862 and norm :: 'a => real.
   863 
   864 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   865 from reals into other types. The overloaded constant Reals :: 'a set
   866 is now defined as range of_real; potential INCOMPATIBILITY.
   867 
   868 * Hyperreal: Several constants that previously worked only for the
   869 reals have been generalized, so they now work over arbitrary vector
   870 spaces. Type annotations may need to be added in some cases; potential
   871 INCOMPATIBILITY.
   872 
   873   Infinitesimal  :: ('a::real_normed_vector) star set"
   874   HFinite        :: ('a::real_normed_vector) star set"
   875   HInfinite      :: ('a::real_normed_vector) star set"
   876   approx         :: ('a::real_normed_vector) star => 'a star => bool
   877   monad          :: ('a::real_normed_vector) star => 'a star set
   878   galaxy         :: ('a::real_normed_vector) star => 'a star set
   879   (NS)LIMSEQ     :: [nat, 'a::real_normed_vector, 'a] => bool
   880   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   881   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   882   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   883   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   884   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   885   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   886 
   887 * Complex: Some complex-specific constants are now abbreviations for
   888 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   889 hnorm.  Other constants have been entirely removed in favor of the
   890 polymorphic versions (INCOMPATIBILITY):
   891 
   892   approx        <-- capprox
   893   HFinite       <-- CFinite
   894   HInfinite     <-- CInfinite
   895   Infinitesimal <-- CInfinitesimal
   896   monad         <-- cmonad
   897   galaxy        <-- cgalaxy
   898   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   899   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   900   (ns)deriv     <-- (ns)cderiv
   901 
   902 
   903 *** ML ***
   904 
   905 * Context data interfaces (Theory/Proof/GenericDataFun): removed
   906 name/print, uninitialized data defaults to ad-hoc copy of empty value,
   907 init only required for impure data.  INCOMPATIBILITY: empty really
   908 need to be empty (no dependencies on theory content!)
   909 
   910 * ML within Isar: antiquotations allow to embed statically-checked
   911 formal entities in the source, referring to the context available at
   912 compile-time.  For example:
   913 
   914 ML {* @{typ "'a => 'b"} *}
   915 ML {* @{term "%x. x"} *}
   916 ML {* @{prop "x == y"} *}
   917 ML {* @{ctyp "'a => 'b"} *}
   918 ML {* @{cterm "%x. x"} *}
   919 ML {* @{cprop "x == y"} *}
   920 ML {* @{thm asm_rl} *}
   921 ML {* @{thms asm_rl} *}
   922 ML {* @{const_name c} *}
   923 ML {* @{const_syntax c} *}
   924 ML {* @{context} *}
   925 ML {* @{theory} *}
   926 ML {* @{theory Pure} *}
   927 ML {* @{simpset} *}
   928 ML {* @{claset} *}
   929 ML {* @{clasimpset} *}
   930 
   931 The same works for sources being ``used'' within an Isar context.
   932 
   933 * ML in Isar: improved error reporting; extra verbosity with
   934 Toplevel.debug enabled.
   935 
   936 * Pure/library:
   937 
   938   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   939   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   940 
   941 The semantics of "burrow" is: "take a function with *simulatanously*
   942 transforms a list of value, and apply it *simulatanously* to a list of
   943 list of values of the appropriate type". Compare this with "map" which
   944 would *not* apply its argument function simulatanously but in
   945 sequence; "fold_burrow" has an additional context.
   946 
   947 * Pure/library: functions map2 and fold2 with curried syntax for
   948 simultanous mapping and folding:
   949 
   950     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   951     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   952 
   953 * Pure/library: indexed lists - some functions in the Isabelle library
   954 treating lists over 'a as finite mappings from [0...n] to 'a have been
   955 given more convenient names and signatures reminiscent of similar
   956 functions for alists, tables, etc:
   957 
   958   val nth: 'a list -> int -> 'a 
   959   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   960   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   961 
   962 Note that fold_index starts counting at index 0, not 1 like foldln
   963 used to.
   964 
   965 * Pure/library: added general ``divide_and_conquer'' combinator on
   966 lists.
   967 
   968 * Pure/General/table.ML: the join operations now works via exceptions
   969 DUP/SAME instead of type option.  This is simpler in simple cases, and
   970 admits slightly more efficient complex applications.
   971 
   972 * Pure: datatype Context.generic joins theory/Proof.context and
   973 provides some facilities for code that works in either kind of
   974 context, notably GenericDataFun for uniform theory and proof data.
   975 
   976 * Pure: 'advanced' translation functions (parse_translation etc.) now
   977 use Context.generic instead of just theory.
   978 
   979 * Pure: simplified internal attribute type, which is now always
   980 Context.generic * thm -> Context.generic * thm.  Global (theory)
   981 vs. local (Proof.context) attributes have been discontinued, while
   982 minimizing code duplication.  Thm.rule_attribute and
   983 Thm.declaration_attribute build canonical attributes; see also
   984 structure Context for further operations on Context.generic, notably
   985 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   986 declarations and definitions.
   987 
   988 * Pure/kernel: consts certification ignores sort constraints given in
   989 signature declarations.  (This information is not relevant to the
   990 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
   991 potential INCOMPATIBILITY.
   992 
   993 * Pure: axiomatic type classes are now purely definitional, with
   994 explicit proofs of class axioms and super class relations performed
   995 internally.  See Pure/axclass.ML for the main internal interfaces --
   996 notably AxClass.define_class supercedes AxClass.add_axclass, and
   997 AxClass.axiomatize_class/classrel/arity supercede
   998 Sign.add_classes/classrel/arities.
   999 
  1000 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1001 global/local versions on theory vs. Proof.context have been
  1002 discontinued; Attrib.syntax and Method.syntax have been adapted
  1003 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1004 attributes, methods, etc.
  1005 
  1006 * Pure: several functions of signature "... -> theory -> theory * ..."
  1007 have been reoriented to "... -> theory -> ... * theory" in order to
  1008 allow natural usage in combination with the ||>, ||>>, |-> and
  1009 fold_map combinators.
  1010 
  1011 * Pure: official theorem names (closed derivations) and additional
  1012 comments (tags) are now strictly separate.  Name hints -- which are
  1013 maintained as tags -- may be attached any time without affecting the
  1014 derivation.
  1015 
  1016 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1017 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1018 achieve the old behaviour.
  1019 
  1020 * Pure: the "Goal" constant is now called "prop", supporting a
  1021 slightly more general idea of ``protecting'' meta-level rule
  1022 statements.
  1023 
  1024 * Pure: Logic.(un)varify only works in a global context, which is now
  1025 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1026 Logic.legacy_(un)varify as temporary workaround.
  1027 
  1028 * Pure: structure Name provides scalable operations for generating
  1029 internal variable names, notably Name.variants etc.  This replaces
  1030 some popular functions from term.ML:
  1031 
  1032   Term.variant		->  Name.variant
  1033   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1034   Term.invent_names	->  Name.invent_list
  1035 
  1036 Note that low-level renaming rarely occurs in new code -- operations
  1037 from structure Variable are used instead (see below).
  1038 
  1039 * Pure: structure Variable provides fundamental operations for proper
  1040 treatment of fixed/schematic variables in a context.  For example,
  1041 Variable.import introduces fixes for schematics of given facts and
  1042 Variable.export reverses the effect (up to renaming) -- this replaces
  1043 various freeze_thaw operations.
  1044 
  1045 * Pure: structure Goal provides simple interfaces for
  1046 init/conclude/finish and tactical prove operations (replacing former
  1047 Tactic.prove).  Goal.prove is the canonical way to prove results
  1048 within a given context; Goal.prove_global is a degraded version for
  1049 theory level goals, including a global Drule.standard.  Note that
  1050 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1051 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1052 in a locale context).
  1053 
  1054 * Isar: simplified treatment of user-level errors, using exception
  1055 ERROR of string uniformly.  Function error now merely raises ERROR,
  1056 without any side effect on output channels.  The Isar toplevel takes
  1057 care of proper display of ERROR exceptions.  ML code may use plain
  1058 handle/can/try; cat_error may be used to concatenate errors like this:
  1059 
  1060   ... handle ERROR msg => cat_error msg "..."
  1061 
  1062 Toplevel ML code (run directly or through the Isar toplevel) may be
  1063 embedded into the Isar toplevel with exception display/debug like
  1064 this:
  1065 
  1066   Isar.toplevel (fn () => ...)
  1067 
  1068 INCOMPATIBILITY, removed special transform_error facilities, removed
  1069 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1070 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1071 -- use plain ERROR instead.
  1072 
  1073 * Isar: theory setup now has type (theory -> theory), instead of a
  1074 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1075 
  1076 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1077 subject to ProofContext.debug/verbose flags.
  1078 
  1079 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1080 theory before entering a proof state.  Transactions now always see a
  1081 quasi-functional intermediate checkpoint, both in interactive and
  1082 batch mode.
  1083 
  1084 * Simplifier: the simpset of a running simplification process now
  1085 contains a proof context (cf. Simplifier.the_context), which is the
  1086 very context that the initial simpset has been retrieved from (by
  1087 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1088 (solver, looper etc.) may depend on arbitrary proof data.
  1089 
  1090 * Simplifier.inherit_context inherits the proof context (plus the
  1091 local bounds) of the current simplification process; any simproc
  1092 etc. that calls the Simplifier recursively should do this!  Removed
  1093 former Simplifier.inherit_bounds, which is already included here --
  1094 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1095 specify an explicit context using Simplifier.context/theory_context.
  1096 
  1097 * Simplifier/Classical Reasoner: more abstract interfaces
  1098 change_simpset/claset for modifying the simpset/claset reference of a
  1099 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1100 INCOMPATIBILITY.
  1101 
  1102 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1103 "Trueprop" etc.
  1104 
  1105 
  1106 *** System ***
  1107 
  1108 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1109 locations -- now includes the Isabelle version identifier as well.
  1110 This simplifies use of multiple Isabelle installations.
  1111 
  1112 * isabelle-process: option -S (secure mode) disables some critical
  1113 operations, notably runtime compilation and evaluation of ML source
  1114 code.
  1115 
  1116 
  1117 New in Isabelle2005 (October 2005)
  1118 ----------------------------------
  1119 
  1120 *** General ***
  1121 
  1122 * Theory headers: the new header syntax for Isar theories is
  1123 
  1124   theory <name>
  1125   imports <theory1> ... <theoryN>
  1126   uses <file1> ... <fileM>
  1127   begin
  1128 
  1129 where the 'uses' part is optional.  The previous syntax
  1130 
  1131   theory <name> = <theory1> + ... + <theoryN>:
  1132 
  1133 will disappear in the next release.  Use isatool fixheaders to convert
  1134 existing theory files.  Note that there is no change in ancient
  1135 non-Isar theories now, but these will disappear soon.
  1136 
  1137 * Theory loader: parent theories can now also be referred to via
  1138 relative and absolute paths.
  1139 
  1140 * Command 'find_theorems' searches for a list of criteria instead of a
  1141 list of constants. Known criteria are: intro, elim, dest, name:string,
  1142 simp:term, and any term. Criteria can be preceded by '-' to select
  1143 theorems that do not match. Intro, elim, dest select theorems that
  1144 match the current goal, name:s selects theorems whose fully qualified
  1145 name contain s, and simp:term selects all simplification rules whose
  1146 lhs match term.  Any other term is interpreted as pattern and selects
  1147 all theorems matching the pattern. Available in ProofGeneral under
  1148 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1149 
  1150   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1151 
  1152 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1153 matching the current goal as introduction rule and not having "HOL."
  1154 in their name (i.e. not being defined in theory HOL).
  1155 
  1156 * Command 'thms_containing' has been discontinued in favour of
  1157 'find_theorems'; INCOMPATIBILITY.
  1158 
  1159 * Communication with Proof General is now 8bit clean, which means that
  1160 Unicode text in UTF-8 encoding may be used within theory texts (both
  1161 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1162 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1163 
  1164   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1165   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1166 
  1167 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1168 Classical Reasoner.  Typical big applications run around 2 times
  1169 faster.
  1170 
  1171 
  1172 *** Document preparation ***
  1173 
  1174 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1175 of raw sources.  Only those symbols that do not require additional
  1176 LaTeX packages (depending on comments in isabellesym.sty) are
  1177 displayed properly, everything else is left verbatim.  isatool display
  1178 and isatool print are used as front ends (these are subject to the
  1179 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1180 
  1181 * Command tags control specific markup of certain regions of text,
  1182 notably folding and hiding.  Predefined tags include "theory" (for
  1183 theory begin and end), "proof" for proof commands, and "ML" for
  1184 commands involving ML code; the additional tags "visible" and
  1185 "invisible" are unused by default.  Users may give explicit tag
  1186 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1187 interpretation of tags is determined by the LaTeX job during document
  1188 preparation: see option -V of isatool usedir, or options -n and -t of
  1189 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1190 \isadroptag.
  1191 
  1192 Several document versions may be produced at the same time via isatool
  1193 usedir (the generated index.html will link all of them).  Typical
  1194 specifications include ''-V document=theory,proof,ML'' to present
  1195 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1196 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1197 these parts without any formal replacement text.  The Isabelle site
  1198 default settings produce ''document'' and ''outline'' versions as
  1199 specified above.
  1200 
  1201 * Several new antiquotations:
  1202 
  1203   @{term_type term} prints a term with its type annotated;
  1204 
  1205   @{typeof term} prints the type of a term;
  1206 
  1207   @{const const} is the same as @{term const}, but checks that the
  1208   argument is a known logical constant;
  1209 
  1210   @{term_style style term} and @{thm_style style thm} print a term or
  1211   theorem applying a "style" to it
  1212 
  1213   @{ML text}
  1214 
  1215 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1216 definitions, equations, inequations etc., 'concl' printing only the
  1217 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1218 to print the specified premise.  TermStyle.add_style provides an ML
  1219 interface for introducing further styles.  See also the "LaTeX Sugar"
  1220 document practical applications.  The ML antiquotation prints
  1221 type-checked ML expressions verbatim.
  1222 
  1223 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1224 and 'text' support optional locale specification '(in loc)', which
  1225 specifies the default context for interpreting antiquotations.  For
  1226 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1227 
  1228 * Option 'locale=NAME' of antiquotations specifies an alternative
  1229 context interpreting the subsequent argument.  For example: @{thm
  1230 [locale=lattice] inf_assoc}.
  1231 
  1232 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1233 a proof context.
  1234 
  1235 * Proper output of antiquotations for theory commands involving a
  1236 proof context (such as 'locale' or 'theorem (in loc) ...').
  1237 
  1238 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1239 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1240 
  1241 * isatool usedir: new option -C (default true) controls whether option
  1242 -D should include a copy of the original document directory; -C false
  1243 prevents unwanted effects such as copying of administrative CVS data.
  1244 
  1245 
  1246 *** Pure ***
  1247 
  1248 * Considerably improved version of 'constdefs' command.  Now performs
  1249 automatic type-inference of declared constants; additional support for
  1250 local structure declarations (cf. locales and HOL records), see also
  1251 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1252 sequential dependencies of definitions within a single 'constdefs'
  1253 section; moreover, the declared name needs to be an identifier.  If
  1254 all fails, consider to fall back on 'consts' and 'defs' separately.
  1255 
  1256 * Improved indexed syntax and implicit structures.  First of all,
  1257 indexed syntax provides a notational device for subscripted
  1258 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1259 expressions.  Secondly, in a local context with structure
  1260 declarations, number indexes \<^sub>n or the empty index (default
  1261 number 1) refer to a certain fixed variable implicitly; option
  1262 show_structs controls printing of implicit structures.  Typical
  1263 applications of these concepts involve record types and locales.
  1264 
  1265 * New command 'no_syntax' removes grammar declarations (and
  1266 translations) resulting from the given syntax specification, which is
  1267 interpreted in the same manner as for the 'syntax' command.
  1268 
  1269 * 'Advanced' translation functions (parse_translation etc.) may depend
  1270 on the signature of the theory context being presently used for
  1271 parsing/printing, see also isar-ref manual.
  1272 
  1273 * Improved 'oracle' command provides a type-safe interface to turn an
  1274 ML expression of type theory -> T -> term into a primitive rule of
  1275 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1276 is already included here); see also FOL/ex/IffExample.thy;
  1277 INCOMPATIBILITY.
  1278 
  1279 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1280 before); "cI" is no longer bound, use "c.intro" instead.
  1281 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1282 axclasses vs. locales.
  1283 
  1284 * Improved internal renaming of symbolic identifiers -- attach primes
  1285 instead of base 26 numbers.
  1286 
  1287 * New flag show_question_marks controls printing of leading question
  1288 marks in schematic variable names.
  1289 
  1290 * In schematic variable names, *any* symbol following \<^isub> or
  1291 \<^isup> is now treated as part of the base name.  For example, the
  1292 following works without printing of awkward ".0" indexes:
  1293 
  1294   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1295     by simp
  1296 
  1297 * Inner syntax includes (*(*nested*) comments*).
  1298 
  1299 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1300 annotations as "(00...)".
  1301 
  1302 * Clear separation of logical types and nonterminals, where the latter
  1303 may only occur in 'syntax' specifications or type abbreviations.
  1304 Before that distinction was only partially implemented via type class
  1305 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1306 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1307 exotic syntax specifications may require further adaption
  1308 (e.g. Cube/Cube.thy).
  1309 
  1310 * Removed obsolete type class "logic", use the top sort {} instead.
  1311 Note that non-logical types should be declared as 'nonterminals'
  1312 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1313 specifications.
  1314 
  1315 * Attributes 'induct' and 'cases': type or set names may now be
  1316 locally fixed variables as well.
  1317 
  1318 * Simplifier: can now control the depth to which conditional rewriting
  1319 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1320 Limit.
  1321 
  1322 * Simplifier: simplification procedures may now take the current
  1323 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1324 interface), which is very useful for calling the Simplifier
  1325 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1326 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1327 low-level mk_simproc no longer applies Logic.varify internally, to
  1328 allow for use in a context of fixed variables.
  1329 
  1330 * thin_tac now works even if the assumption being deleted contains !!
  1331 or ==>.  More generally, erule now works even if the major premise of
  1332 the elimination rule contains !! or ==>.
  1333 
  1334 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1335 
  1336 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1337 from Pure, which contains all common declarations already.  Both
  1338 theories are defined via plain Isabelle/Isar .thy files.
  1339 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1340 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1341 use isatool fixcpure to adapt your theory and ML sources.
  1342 
  1343 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1344 selections of theorems in named facts via index ranges.
  1345 
  1346 * 'print_theorems': in theory mode, really print the difference
  1347 wrt. the last state (works for interactive theory development only),
  1348 in proof mode print all local facts (cf. 'print_facts');
  1349 
  1350 * 'hide': option '(open)' hides only base names.
  1351 
  1352 * More efficient treatment of intermediate checkpoints in interactive
  1353 theory development.
  1354 
  1355 * Code generator is now invoked via code_module (incremental code
  1356 generation) and code_library (modular code generation, ML structures
  1357 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1358 must be quoted when used as identifiers.
  1359 
  1360 * New 'value' command for reading, evaluating and printing terms using
  1361 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1362 quoted when used as identifier.
  1363 
  1364 
  1365 *** Locales ***
  1366 
  1367 * New commands for the interpretation of locale expressions in
  1368 theories (1), locales (2) and proof contexts (3).  These generate
  1369 proof obligations from the expression specification.  After the
  1370 obligations have been discharged, theorems of the expression are added
  1371 to the theory, target locale or proof context.  The synopsis of the
  1372 commands is a follows:
  1373 
  1374   (1) interpretation expr inst
  1375   (2) interpretation target < expr
  1376   (3) interpret expr inst
  1377 
  1378 Interpretation in theories and proof contexts require a parameter
  1379 instantiation of terms from the current context.  This is applied to
  1380 specifications and theorems of the interpreted expression.
  1381 Interpretation in locales only permits parameter renaming through the
  1382 locale expression.  Interpretation is smart in that interpretations
  1383 that are active already do not occur in proof obligations, neither are
  1384 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1385 inspect active interpretations of a particular locale.  For details,
  1386 see the Isar Reference manual.  Examples can be found in
  1387 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1388 
  1389 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1390 'interpret' instead.
  1391 
  1392 * New context element 'constrains' for adding type constraints to
  1393 parameters.
  1394 
  1395 * Context expressions: renaming of parameters with syntax
  1396 redeclaration.
  1397 
  1398 * Locale declaration: 'includes' disallowed.
  1399 
  1400 * Proper static binding of attribute syntax -- i.e. types / terms /
  1401 facts mentioned as arguments are always those of the locale definition
  1402 context, independently of the context of later invocations.  Moreover,
  1403 locale operations (renaming and type / term instantiation) are applied
  1404 to attribute arguments as expected.
  1405 
  1406 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1407 actual attributes; rare situations may require Attrib.attribute to
  1408 embed those attributes into Attrib.src that lack concrete syntax.
  1409 Attribute implementations need to cooperate properly with the static
  1410 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1411 Attrib.XXX_thm etc. already do the right thing without further
  1412 intervention.  Only unusual applications -- such as "where" or "of"
  1413 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1414 on the context and the facts involved -- may have to assign parsed
  1415 values to argument tokens explicitly.
  1416 
  1417 * Changed parameter management in theorem generation for long goal
  1418 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1419 theorem statement in rare situations.
  1420 
  1421 * Locale inspection command 'print_locale' omits notes elements.  Use
  1422 'print_locale!' to have them included in the output.
  1423 
  1424 
  1425 *** Provers ***
  1426 
  1427 * Provers/hypsubst.ML: improved version of the subst method, for
  1428 single-step rewriting: it now works in bound variable contexts. New is
  1429 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1430 rewrite a different subterm than the original subst method, which is
  1431 still available as 'simplesubst'.
  1432 
  1433 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1434 and quasi orders.
  1435 
  1436 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1437 reflexive-transitive closure of relations.
  1438 
  1439 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1440 limit (previously hard-coded with a value of 20) user-definable.
  1441 
  1442 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1443 is peformed already.  Object-logics merely need to finish their
  1444 initial simpset configuration as before.  INCOMPATIBILITY.
  1445 
  1446 
  1447 *** HOL ***
  1448 
  1449 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1450 
  1451   syntax (epsilon)
  1452     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1453 
  1454 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1455 and x-symbol; use option '-m epsilon' to get it actually printed.
  1456 Moreover, the mathematically important symbolic identifier \<epsilon>
  1457 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1458 
  1459 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1460 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1461 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1462 support corresponding Isar calculations.
  1463 
  1464 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1465 instead of ":".
  1466 
  1467 * theory SetInterval: changed the syntax for open intervals:
  1468 
  1469   Old       New
  1470   {..n(}    {..<n}
  1471   {)n..}    {n<..}
  1472   {m..n(}   {m..<n}
  1473   {)m..n}   {m<..n}
  1474   {)m..n(}  {m<..<n}
  1475 
  1476 The old syntax is still supported but will disappear in the next
  1477 release.  For conversion use the following Emacs search and replace
  1478 patterns (these are not perfect but work quite well):
  1479 
  1480   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1481   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1482 
  1483 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1484 equalities in commutative rings; method 'algebra' provides a generic
  1485 interface.
  1486 
  1487 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1488 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1489 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1490 be a tuple pattern.
  1491 
  1492 Some new syntax forms are available:
  1493 
  1494   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1495   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1496   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1497   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1498 
  1499 The latter form "\<Sum>x < k. e" used to be based on a separate
  1500 function "Summation", which has been discontinued.
  1501 
  1502 * theory Finite_Set: in structured induction proofs, the insert case
  1503 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1504 (insert F x)'.
  1505 
  1506 * The 'refute' command has been extended to support a much larger
  1507 fragment of HOL, including axiomatic type classes, constdefs and
  1508 typedefs, inductive datatypes and recursion.
  1509 
  1510 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1511 Requires zChaff with proof generation to be installed.  See
  1512 HOL/ex/SAT_Examples.thy for examples.
  1513 
  1514 * Datatype induction via method 'induct' now preserves the name of the
  1515 induction variable. For example, when proving P(xs::'a list) by
  1516 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1517 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1518 in unstructured proof scripts.
  1519 
  1520 * Reworked implementation of records.  Improved scalability for
  1521 records with many fields, avoiding performance problems for type
  1522 inference. Records are no longer composed of nested field types, but
  1523 of nested extension types. Therefore the record type only grows linear
  1524 in the number of extensions and not in the number of fields.  The
  1525 top-level (users) view on records is preserved.  Potential
  1526 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1527 old record representation. The type generated for a record is called
  1528 <record_name>_ext_type.
  1529 
  1530 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1531 proofs triggered by a record definition or a simproc (if
  1532 quick_and_dirty is enabled).  Definitions of large records can take
  1533 quite long.
  1534 
  1535 New simproc record_upd_simproc for simplification of multiple record
  1536 updates enabled by default.  Moreover, trivial updates are also
  1537 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1538 occasionally, since simplification is more powerful by default.
  1539 
  1540 * typedef: proper support for polymorphic sets, which contain extra
  1541 type-variables in the term.
  1542 
  1543 * Simplifier: automatically reasons about transitivity chains
  1544 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1545 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1546 old proofs break occasionally as simplification may now solve more
  1547 goals than previously.
  1548 
  1549 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1550 present.  Works for all partial orders (class "order"), in particular
  1551 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1552 just like y <= x.
  1553 
  1554 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1555 bound variable or a constant then the let is unfolded.  Otherwise
  1556 first a is simplified to b, and then f b is simplified to g. If
  1557 possible we abstract b from g arriving at "let x = b in h x",
  1558 otherwise we unfold the let and arrive at g.  The simproc can be
  1559 enabled/disabled by the reference use_let_simproc.  Potential
  1560 INCOMPATIBILITY since simplification is more powerful by default.
  1561 
  1562 * Classical reasoning: the meson method now accepts theorems as arguments.
  1563 
  1564 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1565 jobs to provide advice on the provability of subgoals.
  1566 
  1567 * Theory OrderedGroup and Ring_and_Field: various additions and
  1568 improvements to faciliate calculations involving equalities and
  1569 inequalities.
  1570 
  1571 The following theorems have been eliminated or modified
  1572 (INCOMPATIBILITY):
  1573 
  1574   abs_eq             now named abs_of_nonneg
  1575   abs_of_ge_0        now named abs_of_nonneg
  1576   abs_minus_eq       now named abs_of_nonpos
  1577   imp_abs_id         now named abs_of_nonneg
  1578   imp_abs_neg_id     now named abs_of_nonpos
  1579   mult_pos           now named mult_pos_pos
  1580   mult_pos_le        now named mult_nonneg_nonneg
  1581   mult_pos_neg_le    now named mult_nonneg_nonpos
  1582   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1583   mult_neg           now named mult_neg_neg
  1584   mult_neg_le        now named mult_nonpos_nonpos
  1585 
  1586 * Theory Parity: added rules for simplifying exponents.
  1587 
  1588 * Theory List:
  1589 
  1590 The following theorems have been eliminated or modified
  1591 (INCOMPATIBILITY):
  1592 
  1593   list_all_Nil       now named list_all.simps(1)
  1594   list_all_Cons      now named list_all.simps(2)
  1595   list_all_conv      now named list_all_iff
  1596   set_mem_eq         now named mem_iff
  1597 
  1598 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1599 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1600 
  1601 
  1602 *** HOL-Complex ***
  1603 
  1604 * Theory RealDef: better support for embedding natural numbers and
  1605 integers in the reals.
  1606 
  1607 The following theorems have been eliminated or modified
  1608 (INCOMPATIBILITY):
  1609 
  1610   exp_ge_add_one_self  now requires no hypotheses
  1611   real_of_int_add      reversed direction of equality (use [symmetric])
  1612   real_of_int_minus    reversed direction of equality (use [symmetric])
  1613   real_of_int_diff     reversed direction of equality (use [symmetric])
  1614   real_of_int_mult     reversed direction of equality (use [symmetric])
  1615 
  1616 * Theory RComplete: expanded support for floor and ceiling functions.
  1617 
  1618 * Theory Ln is new, with properties of the natural logarithm
  1619 
  1620 * Hyperreal: There is a new type constructor "star" for making
  1621 nonstandard types.  The old type names are now type synonyms:
  1622 
  1623   hypreal = real star
  1624   hypnat = nat star
  1625   hcomplex = complex star
  1626 
  1627 * Hyperreal: Many groups of similarly-defined constants have been
  1628 replaced by polymorphic versions (INCOMPATIBILITY):
  1629 
  1630   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1631 
  1632   starset      <-- starsetNat, starsetC
  1633   *s*          <-- *sNat*, *sc*
  1634   starset_n    <-- starsetNat_n, starsetC_n
  1635   *sn*         <-- *sNatn*, *scn*
  1636   InternalSets <-- InternalNatSets, InternalCSets
  1637 
  1638   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1639   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1640   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1641   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1642   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1643 
  1644 * Hyperreal: Many type-specific theorems have been removed in favor of
  1645 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1646 
  1647   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1648   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1649   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1650   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1651   right_minus <-- hypreal_add_minus
  1652   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1653   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1654   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1655   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1656   mult_1_right <-- hcomplex_mult_one_right
  1657   mult_zero_left <-- hcomplex_mult_zero_left
  1658   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1659   right_distrib <-- hypnat_add_mult_distrib2
  1660   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1661   right_inverse <-- hypreal_mult_inverse
  1662   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1663   order_refl <-- {hypreal,hypnat}_le_refl
  1664   order_trans <-- {hypreal,hypnat}_le_trans
  1665   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1666   order_less_le <-- {hypreal,hypnat}_less_le
  1667   linorder_linear <-- {hypreal,hypnat}_le_linear
  1668   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1669   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1670   add_nonneg_nonneg <-- hypreal_le_add_order
  1671 
  1672 * Hyperreal: Separate theorems having to do with type-specific
  1673 versions of constants have been merged into theorems that apply to the
  1674 new polymorphic constants (INCOMPATIBILITY):
  1675 
  1676   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1677   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1678   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1679   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1680   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1681   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1682   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1683   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1684   STAR_diff <-- {STAR,STARC}_diff
  1685   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1686     STARC_hcomplex_of_complex}_image_subset
  1687   starset_n_Un <-- starset{Nat,C}_n_Un
  1688   starset_n_Int <-- starset{Nat,C}_n_Int
  1689   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1690   starset_n_diff <-- starset{Nat,C}_n_diff
  1691   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1692   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1693   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1694   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1695   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1696   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1697   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1698   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1699   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1700   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1701   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1702   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1703   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1704   starfun_diff <-- starfun{C,RC,CR}_diff
  1705   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1706   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1707   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1708   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1709   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1710   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1711   starfun_Id <-- starfunC_Id
  1712   starfun_approx <-- starfun{Nat,CR}_approx
  1713   starfun_capprox <-- starfun{C,RC}_capprox
  1714   starfun_abs <-- starfunNat_rabs
  1715   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1716   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1717   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1718   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1719   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1720   starfun_add_approx <-- starfunCR_add_approx
  1721   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1722   starfun_divide <-- starfun{C,CR,RC}_divide
  1723   starfun_n <-- starfun{Nat,C}_n
  1724   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1725   starfun_n_add <-- starfun{Nat,C}_n_add
  1726   starfun_n_add_minus <-- starfunNat_n_add_minus
  1727   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1728   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1729   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1730 
  1731   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1732   star_n_minus <-- {hypreal,hcomplex}_minus
  1733   star_n_diff <-- {hypreal,hcomplex}_diff
  1734   star_n_mult <-- {hypreal,hcomplex}_mult
  1735   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1736   star_n_le <-- {hypreal,hypnat}_le
  1737   star_n_less <-- {hypreal,hypnat}_less
  1738   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1739   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1740   star_n_abs <-- hypreal_hrabs
  1741   star_n_divide <-- hcomplex_divide
  1742 
  1743   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1744   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1745   star_of_diff <-- hypreal_of_real_diff
  1746   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1747   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1748   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1749   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1750   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1751   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1752   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1753   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1754   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1755   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1756   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1757   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1758   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1759   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1760   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1761   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1762   star_of_power <-- hypreal_of_real_power
  1763   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1764 
  1765 * Hyperreal: new method "transfer" that implements the transfer
  1766 principle of nonstandard analysis. With a subgoal that mentions
  1767 nonstandard types like "'a star", the command "apply transfer"
  1768 replaces it with an equivalent one that mentions only standard types.
  1769 To be successful, all free variables must have standard types; non-
  1770 standard variables must have explicit universal quantifiers.
  1771 
  1772 * Hyperreal: A theory of Taylor series.
  1773 
  1774 
  1775 *** HOLCF ***
  1776 
  1777 * Discontinued special version of 'constdefs' (which used to support
  1778 continuous functions) in favor of the general Pure one with full
  1779 type-inference.
  1780 
  1781 * New simplification procedure for solving continuity conditions; it
  1782 is much faster on terms with many nested lambda abstractions (cubic
  1783 instead of exponential time).
  1784 
  1785 * New syntax for domain package: selector names are now optional.
  1786 Parentheses should be omitted unless argument is lazy, for example:
  1787 
  1788   domain 'a stream = cons "'a" (lazy "'a stream")
  1789 
  1790 * New command 'fixrec' for defining recursive functions with pattern
  1791 matching; defining multiple functions with mutual recursion is also
  1792 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1793 sinr, or any data constructor defined by the domain package. The given
  1794 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1795 syntax and examples.
  1796 
  1797 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1798 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1799 but the proof obligation additionally includes an admissibility
  1800 requirement. The packages generate instances of class cpo or pcpo,
  1801 with continuity and strictness theorems for Rep and Abs.
  1802 
  1803 * HOLCF: Many theorems have been renamed according to a more standard naming
  1804 scheme (INCOMPATIBILITY):
  1805 
  1806   foo_inject:  "foo$x = foo$y ==> x = y"
  1807   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1808   foo_less:    "(foo$x << foo$y) = (x << y)"
  1809   foo_strict:  "foo$UU = UU"
  1810   foo_defined: "... ==> foo$x ~= UU"
  1811   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1812 
  1813 
  1814 *** ZF ***
  1815 
  1816 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1817 including the First Isomorphism Theorem (on quotienting by the kernel
  1818 of a homomorphism).
  1819 
  1820 * ZF/Simplifier: install second copy of type solver that actually
  1821 makes use of TC rules declared to Isar proof contexts (or locales);
  1822 the old version is still required for ML proof scripts.
  1823 
  1824 
  1825 *** Cube ***
  1826 
  1827 * Converted to Isar theory format; use locales instead of axiomatic
  1828 theories.
  1829 
  1830 
  1831 *** ML ***
  1832 
  1833 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1834 for ||>, ||>>, |>>,
  1835 
  1836 * Pure/library.ML no longer defines its own option datatype, but uses
  1837 that of the SML basis, which has constructors NONE and SOME instead of
  1838 None and Some, as well as exception Option.Option instead of OPTION.
  1839 The functions the, if_none, is_some, is_none have been adapted
  1840 accordingly, while Option.map replaces apsome.
  1841 
  1842 * Pure/library.ML: the exception LIST has been given up in favour of
  1843 the standard exceptions Empty and Subscript, as well as
  1844 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1845 superceded by the standard hd and tl functions etc.
  1846 
  1847 A number of basic list functions are no longer exported to the ML
  1848 toplevel, as they are variants of predefined functions.  The following
  1849 suggests how one can translate existing code:
  1850 
  1851     rev_append xs ys = List.revAppend (xs, ys)
  1852     nth_elem (i, xs) = List.nth (xs, i)
  1853     last_elem xs = List.last xs
  1854     flat xss = List.concat xss
  1855     seq fs = List.app fs
  1856     partition P xs = List.partition P xs
  1857     mapfilter f xs = List.mapPartial f xs
  1858 
  1859 * Pure/library.ML: several combinators for linear functional
  1860 transformations, notably reverse application and composition:
  1861 
  1862   x |> f                f #> g
  1863   (x, y) |-> f          f #-> g
  1864 
  1865 * Pure/library.ML: introduced/changed precedence of infix operators:
  1866 
  1867   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1868   infix 2 ?;
  1869   infix 3 o oo ooo oooo;
  1870   infix 4 ~~ upto downto;
  1871 
  1872 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1873 infix operators.
  1874 
  1875 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1876 fold_map support linear functional transformations and nesting.  For
  1877 example:
  1878 
  1879   fold f [x1, ..., xN] y =
  1880     y |> f x1 |> ... |> f xN
  1881 
  1882   (fold o fold) f [xs1, ..., xsN] y =
  1883     y |> fold f xs1 |> ... |> fold f xsN
  1884 
  1885   fold f [x1, ..., xN] =
  1886     f x1 #> ... #> f xN
  1887 
  1888   (fold o fold) f [xs1, ..., xsN] =
  1889     fold f xs1 #> ... #> fold f xsN
  1890 
  1891 * Pure/library.ML: the following selectors on type 'a option are
  1892 available:
  1893 
  1894   the:               'a option -> 'a  (*partial*)
  1895   these:             'a option -> 'a  where 'a = 'b list
  1896   the_default: 'a -> 'a option -> 'a
  1897   the_list:          'a option -> 'a list
  1898 
  1899 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1900 basic operations for association lists, following natural argument
  1901 order; moreover the explicit equality predicate passed here avoids
  1902 potentially expensive polymorphic runtime equality checks.
  1903 The old functions may be expressed as follows:
  1904 
  1905   assoc = uncurry (AList.lookup (op =))
  1906   assocs = these oo AList.lookup (op =)
  1907   overwrite = uncurry (AList.update (op =)) o swap
  1908 
  1909 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1910 
  1911   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1912   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1913 
  1914 replacing make_keylist and keyfilter (occassionally used)
  1915 Naive rewrites:
  1916 
  1917   make_keylist = AList.make
  1918   keyfilter = AList.find (op =)
  1919 
  1920 * eq_fst and eq_snd now take explicit equality parameter, thus
  1921   avoiding eqtypes. Naive rewrites:
  1922 
  1923     eq_fst = eq_fst (op =)
  1924     eq_snd = eq_snd (op =)
  1925 
  1926 * Removed deprecated apl and apr (rarely used).
  1927   Naive rewrites:
  1928 
  1929     apl (n, op) =>>= curry op n
  1930     apr (op, m) =>>= fn n => op (n, m)
  1931 
  1932 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1933 provides a reasonably efficient light-weight implementation of sets as
  1934 lists.
  1935 
  1936 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1937 few new operations; existing lookup and update are now curried to
  1938 follow natural argument order (for use with fold etc.);
  1939 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1940 
  1941 * Pure/General: output via the Isabelle channels of
  1942 writeln/warning/error etc. is now passed through Output.output, with a
  1943 hook for arbitrary transformations depending on the print_mode
  1944 (cf. Output.add_mode -- the first active mode that provides a output
  1945 function wins).  Already formatted output may be embedded into further
  1946 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1947 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1948 accommodate easy composition of diagnostic messages etc.  Programmers
  1949 rarely need to care about Output.output or Output.raw at all, with
  1950 some notable exceptions: Output.output is required when bypassing the
  1951 standard channels (writeln etc.), or in token translations to produce
  1952 properly formatted results; Output.raw is required when capturing
  1953 already output material that will eventually be presented to the user
  1954 a second time.  For the default print mode, both Output.output and
  1955 Output.raw have no effect.
  1956 
  1957 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1958 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1959 cumulative results are displayed at the end of a batch session.
  1960 
  1961 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1962 replaced by File.platform_path and File.shell_path (with appropriate
  1963 hooks).  This provides a clean interface for unusual systems where the
  1964 internal and external process view of file names are different.
  1965 
  1966 * Pure: more efficient orders for basic syntactic entities: added
  1967 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1968 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1969 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1970 orders now -- potential INCOMPATIBILITY for code that depends on a
  1971 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1972 Library.sort_strings on result).
  1973 
  1974 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1975 fold_types traverse types/terms from left to right, observing natural
  1976 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1977 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1978 
  1979 * Pure: name spaces have been refined, with significant changes of the
  1980 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1981 to extern(_table).  The plain name entry path is superceded by a
  1982 general 'naming' context, which also includes the 'policy' to produce
  1983 a fully qualified name and external accesses of a fully qualified
  1984 name; NameSpace.extend is superceded by context dependent
  1985 Sign.declare_name.  Several theory and proof context operations modify
  1986 the naming context.  Especially note Theory.restore_naming and
  1987 ProofContext.restore_naming to get back to a sane state; note that
  1988 Theory.add_path is no longer sufficient to recover from
  1989 Theory.absolute_path in particular.
  1990 
  1991 * Pure: new flags short_names (default false) and unique_names
  1992 (default true) for controlling output of qualified names.  If
  1993 short_names is set, names are printed unqualified.  If unique_names is
  1994 reset, the name prefix is reduced to the minimum required to achieve
  1995 the original result when interning again, even if there is an overlap
  1996 with earlier declarations.
  1997 
  1998 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1999 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2000 (useful for printing error messages).  INCOMPATIBILITY.
  2001 
  2002 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2003 Theory.theory are now identified, referring to the universal
  2004 Context.theory (see Pure/context.ML).  Actual signature and theory
  2005 content is managed as theory data.  The old code and interfaces were
  2006 spread over many files and structures; the new arrangement introduces
  2007 considerable INCOMPATIBILITY to gain more clarity:
  2008 
  2009   Context -- theory management operations (name, identity, inclusion,
  2010     parents, ancestors, merge, etc.), plus generic theory data;
  2011 
  2012   Sign -- logical signature and syntax operations (declaring consts,
  2013     types, etc.), plus certify/read for common entities;
  2014 
  2015   Theory -- logical theory operations (stating axioms, definitions,
  2016     oracles), plus a copy of logical signature operations (consts,
  2017     types, etc.); also a few basic management operations (Theory.copy,
  2018     Theory.merge, etc.)
  2019 
  2020 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2021 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2022 for convenience -- they merely return the theory.
  2023 
  2024 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2025 
  2026 * Pure: the Isar proof context type is already defined early in Pure
  2027 as Context.proof (note that ProofContext.context and Proof.context are
  2028 aliases, where the latter is the preferred name).  This enables other
  2029 Isabelle components to refer to that type even before Isar is present.
  2030 
  2031 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2032 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2033 any of these kinds.  For example, Sign.intern typeK is now
  2034 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2035 Theory.hide_types.  Also note that former
  2036 Theory.hide_classes/types/consts are now
  2037 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2038 internalize their arguments!  INCOMPATIBILITY.
  2039 
  2040 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2041 datatype thmref (with constructors Name and NameSelection) instead of
  2042 plain string -- INCOMPATIBILITY;
  2043 
  2044 * Pure: cases produced by proof methods specify options, where NONE
  2045 means to remove case bindings -- INCOMPATIBILITY in
  2046 (RAW_)METHOD_CASES.
  2047 
  2048 * Pure: the following operations retrieve axioms or theorems from a
  2049 theory node or theory hierarchy, respectively:
  2050 
  2051   Theory.axioms_of: theory -> (string * term) list
  2052   Theory.all_axioms_of: theory -> (string * term) list
  2053   PureThy.thms_of: theory -> (string * thm) list
  2054   PureThy.all_thms_of: theory -> (string * thm) list
  2055 
  2056 * Pure: print_tac now outputs the goal through the trace channel.
  2057 
  2058 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2059 Reference Toplevel.debug (default false) controls detailed printing
  2060 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2061 controls execution profiling -- set to 1 for time and 2 for space
  2062 (both increase the runtime).
  2063 
  2064 * Isar session: The initial use of ROOT.ML is now always timed,
  2065 i.e. the log will show the actual process times, in contrast to the
  2066 elapsed wall-clock time that the outer shell wrapper produces.
  2067 
  2068 * Simplifier: improved handling of bound variables (nameless
  2069 representation, avoid allocating new strings).  Simprocs that invoke
  2070 the Simplifier recursively should use Simplifier.inherit_bounds to
  2071 avoid local name clashes.  Failure to do so produces warnings
  2072 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2073 for further details.
  2074 
  2075 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2076 bindings for all theorems stored within a given theory; this may help
  2077 in porting non-Isar theories to Isar ones, while keeping ML proof
  2078 scripts for the time being.
  2079 
  2080 * ML operator HTML.with_charset specifies the charset begin used for
  2081 generated HTML files.  For example:
  2082 
  2083   HTML.with_charset "utf-8" use_thy "Hebrew";
  2084   HTML.with_charset "utf-8" use_thy "Chinese";
  2085 
  2086 
  2087 *** System ***
  2088 
  2089 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2090 isabelle, isatool etc.).
  2091 
  2092 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2093 isatool doc, isatool mkdir, display_drafts etc.).
  2094 
  2095 * isatool usedir: option -f allows specification of the ML file to be
  2096 used by Isabelle; default is ROOT.ML.
  2097 
  2098 * New isatool version outputs the version identifier of the Isabelle
  2099 distribution being used.
  2100 
  2101 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2102 (containing Boolean satisfiability problems) into Isabelle/HOL
  2103 theories.
  2104 
  2105 
  2106 
  2107 New in Isabelle2004 (April 2004)
  2108 --------------------------------
  2109 
  2110 *** General ***
  2111 
  2112 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2113   Replaces linorder.ML.
  2114 
  2115 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2116   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2117   (\<a>...\<z>), are now considered normal letters, and can therefore
  2118   be used anywhere where an ASCII letter (a...zA...Z) has until
  2119   now. COMPATIBILITY: This obviously changes the parsing of some
  2120   terms, especially where a symbol has been used as a binder, say
  2121   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2122   as an identifier.  Fix it by inserting a space around former
  2123   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2124   existing theory and ML files.
  2125 
  2126 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2127 
  2128 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2129   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2130   a normal (but invisible) letter. For multiple letter subscripts repeat
  2131   \<^isub> like this: x\<^isub>1\<^isub>2.
  2132 
  2133 * Pure: There are now sub-/superscripts that can span more than one
  2134   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2135   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2136   superscript. The new control characters are not identifier parts.
  2137 
  2138 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2139   content of "..." to the latex file instead of \isacntrl... . The "..."
  2140   may consist of any printable characters excluding the end bracket >.
  2141 
  2142 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2143   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2144   declare constants "final", which prevents their being given a definition
  2145   later.  It is useful for constants whose behaviour is fixed axiomatically
  2146   rather than definitionally, such as the meta-logic connectives.
  2147 
  2148 * Pure: 'instance' now handles general arities with general sorts
  2149   (i.e. intersections of classes),
  2150 
  2151 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2152   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2153   It can be changed to alter the colors/layout of generated pages.
  2154 
  2155 
  2156 *** Isar ***
  2157 
  2158 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2159   cut_tac, subgoal_tac and thin_tac:
  2160   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2161     locales are no longer forced to write Isar proof scripts.
  2162     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2163     emulations.
  2164   - INCOMPATIBILITY: names of variables to be instantiated may no
  2165     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2166     This is consistent with the instantiation attribute "where".
  2167 
  2168 * Attributes "where" and "of":
  2169   - Now take type variables of instantiated theorem into account when reading
  2170     the instantiation string.  This fixes a bug that caused instantiated
  2171     theorems to have too special types in some circumstances.
  2172   - "where" permits explicit instantiations of type variables.
  2173 
  2174 * Calculation commands "moreover" and "also" no longer interfere with
  2175   current facts ("this"), admitting arbitrary combinations with "then"
  2176   and derived forms.
  2177 
  2178 * Locales:
  2179   - Goal statements involving the context element "includes" no longer
  2180     generate theorems with internal delta predicates (those ending on
  2181     "_axioms") in the premise.
  2182     Resolve particular premise with <locale>.intro to obtain old form.
  2183   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2184     specification and "includes" elements in goal statement.
  2185   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2186     [intro?] and [elim?] (respectively) by default.
  2187   - Experimental command for instantiation of locales in proof contexts:
  2188         instantiate <label>[<attrs>]: <loc>
  2189     Instantiates locale <loc> and adds all its theorems to the current context
  2190     taking into account their attributes.  Label and attrs are optional
  2191     modifiers, like in theorem declarations.  If present, names of
  2192     instantiated theorems are qualified with <label>, and the attributes
  2193     <attrs> are applied after any attributes these theorems might have already.
  2194       If the locale has assumptions, a chained fact of the form
  2195     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2196     are derived.  The command does not support old-style locales declared
  2197     with "locale (open)".
  2198       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2199 
  2200 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2201   (Isar) contexts.
  2202 
  2203 
  2204 *** HOL ***
  2205 
  2206 * Proof import: new image HOL4 contains the imported library from
  2207   the HOL4 system with about 2500 theorems. It is imported by
  2208   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2209   can be used like any other Isabelle image.  See
  2210   HOL/Import/HOL/README for more information.
  2211 
  2212 * Simplifier:
  2213   - Much improved handling of linear and partial orders.
  2214     Reasoners for linear and partial orders are set up for type classes
  2215     "linorder" and "order" respectively, and are added to the default simpset
  2216     as solvers.  This means that the simplifier can build transitivity chains
  2217     to solve goals from the assumptions.
  2218   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2219     of blast or auto after simplification become unnecessary because the goal
  2220     is solved by simplification already.
  2221 
  2222 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2223     all proved in axiomatic type classes for semirings, rings and fields.
  2224 
  2225 * Numerics:
  2226   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2227     now formalized using the Ring_and_Field theory mentioned above.
  2228   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2229     than before, because now they are set up once in a generic manner.
  2230   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2231     Look for the general versions in Ring_and_Field (and Power if they concern
  2232     exponentiation).
  2233 
  2234 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2235 
  2236 * Records:
  2237   - Record types are now by default printed with their type abbreviation
  2238     instead of the list of all field types. This can be configured via
  2239     the reference "print_record_type_abbr".
  2240   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2241     (not enabled by default).
  2242   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2243     EX x. x = sel r to True (not enabled by default).
  2244   - Tactic "record_split_simp_tac" to split and simplify records added.
  2245 
  2246 * 'specification' command added, allowing for definition by
  2247   specification.  There is also an 'ax_specification' command that
  2248   introduces the new constants axiomatically.
  2249 
  2250 * arith(_tac) is now able to generate counterexamples for reals as well.
  2251 
  2252 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2253 
  2254 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2255   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2256 
  2257 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2258   matrix theory to linear programming.
  2259 
  2260 * Unions and Intersections:
  2261   The latex output syntax of UN and INT has been changed
  2262   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2263   i.e. the index formulae has become a subscript.
  2264   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2265 
  2266 * Unions and Intersections over Intervals:
  2267   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2268   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2269   like in normal math, and corresponding versions for < and for intersection.
  2270 
  2271 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2272   lexicographic dictonary ordering has been added as "lexord".
  2273 
  2274 * ML: the legacy theory structures Int and List have been removed. They had
  2275   conflicted with ML Basis Library structures having the same names.
  2276 
  2277 * 'refute' command added to search for (finite) countermodels.  Only works
  2278   for a fragment of HOL.  The installation of an external SAT solver is
  2279   highly recommended.  See "HOL/Refute.thy" for details.
  2280 
  2281 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2282   formulae under an assignment of free variables to random values.
  2283   In contrast to 'refute', it can deal with inductive datatypes,
  2284   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2285   for examples.
  2286 
  2287 
  2288 *** HOLCF ***
  2289 
  2290 * Streams now come with concatenation and are part of the HOLCF image
  2291 
  2292 
  2293 
  2294 New in Isabelle2003 (May 2003)
  2295 ------------------------------
  2296 
  2297 *** General ***
  2298 
  2299 * Provers/simplifier:
  2300 
  2301   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2302     Assumptions are now subject to complete mutual simplification,
  2303     not just from left to right. The simplifier now preserves
  2304     the order of assumptions.
  2305 
  2306     Potential INCOMPATIBILITY:
  2307 
  2308     -- simp sometimes diverges where the old version did
  2309        not, e.g. invoking simp on the goal
  2310 
  2311         [| P (f x); y = x; f x = f y |] ==> Q
  2312 
  2313        now gives rise to the infinite reduction sequence
  2314 
  2315         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2316 
  2317        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2318        kind of problem.
  2319 
  2320     -- Tactics combining classical reasoner and simplification (such as auto)
  2321        are also affected by this change, because many of them rely on
  2322        simp. They may sometimes diverge as well or yield a different numbers
  2323        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2324        in case of problems. Sometimes subsequent calls to the classical
  2325        reasoner will fail because a preceeding call to the simplifier too
  2326        eagerly simplified the goal, e.g. deleted redundant premises.
  2327 
  2328   - The simplifier trace now shows the names of the applied rewrite rules
  2329 
  2330   - You can limit the number of recursive invocations of the simplifier
  2331     during conditional rewriting (where the simplifie tries to solve the
  2332     conditions before applying the rewrite rule):
  2333     ML "simp_depth_limit := n"
  2334     where n is an integer. Thus you can force termination where previously
  2335     the simplifier would diverge.
  2336 
  2337   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2338 
  2339   - No longer aborts on failed congruence proof.  Instead, the
  2340     congruence is ignored.
  2341 
  2342 * Pure: New generic framework for extracting programs from constructive
  2343   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2344   as HOL/Extraction for some case studies.
  2345 
  2346 * Pure: The main goal of the proof state is no longer shown by default, only
  2347 the subgoals. This behaviour is controlled by a new flag.
  2348    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2349 (ML: Proof.show_main_goal).
  2350 
  2351 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2352 rules whose conclusion matches subgoal 1:
  2353       PG menu: Isabelle/Isar -> Show me -> matching rules
  2354 The rules are ordered by how closely they match the subgoal.
  2355 In particular, rules that solve a subgoal outright are displayed first
  2356 (or rather last, the way they are printed).
  2357 (ML: ProofGeneral.print_intros())
  2358 
  2359 * Pure: New flag trace_unify_fail causes unification to print
  2360 diagnostic information (PG: in trace buffer) when it fails. This is
  2361 useful for figuring out why single step proofs like rule, erule or
  2362 assumption failed.
  2363 
  2364 * Pure: Locale specifications now produce predicate definitions
  2365 according to the body of text (covering assumptions modulo local
  2366 definitions); predicate "loc_axioms" covers newly introduced text,
  2367 while "loc" is cumulative wrt. all included locale expressions; the
  2368 latter view is presented only on export into the global theory
  2369 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2370 on the old view without predicates;
  2371 
  2372 * Pure: predefined locales "var" and "struct" are useful for sharing
  2373 parameters (as in CASL, for example); just specify something like
  2374 ``var x + var y + struct M'' as import;
  2375 
  2376 * Pure: improved thms_containing: proper indexing of facts instead of
  2377 raw theorems; check validity of results wrt. current name space;
  2378 include local facts of proof configuration (also covers active
  2379 locales), cover fixed variables in index; may use "_" in term
  2380 specification; an optional limit for the number of printed facts may
  2381 be given (the default is 40);
  2382 
  2383 * Pure: disallow duplicate fact bindings within new-style theory files
  2384 (batch-mode only);
  2385 
  2386 * Provers: improved induct method: assumptions introduced by case
  2387 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2388 the goal statement); "foo" still refers to all facts collectively;
  2389 
  2390 * Provers: the function blast.overloaded has been removed: all constants
  2391 are regarded as potentially overloaded, which improves robustness in exchange
  2392 for slight decrease in efficiency;
  2393 
  2394 * Provers/linorder: New generic prover for transitivity reasoning over
  2395 linear orders.  Note: this prover is not efficient!
  2396 
  2397 * Isar: preview of problems to finish 'show' now produce an error
  2398 rather than just a warning (in interactive mode);
  2399 
  2400 
  2401 *** HOL ***
  2402 
  2403 * arith(_tac)
  2404 
  2405  - Produces a counter example if it cannot prove a goal.
  2406    Note that the counter example may be spurious if the goal is not a formula
  2407    of quantifier-free linear arithmetic.
  2408    In ProofGeneral the counter example appears in the trace buffer.
  2409 
  2410  - Knows about div k and mod k where k is a numeral of type nat or int.
  2411 
  2412  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2413    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2414    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2415 
  2416 * simp's arithmetic capabilities have been enhanced a bit: it now
  2417 takes ~= in premises into account (by performing a case split);
  2418 
  2419 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2420 are distributed over a sum of terms;
  2421 
  2422 * New tactic "trans_tac" and method "trans" instantiate
  2423 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2424 "<=", "<" and "=").
  2425 
  2426 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2427 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2428 
  2429 * 'typedef' command has new option "open" to suppress the set
  2430 definition;
  2431 
  2432 * functions Min and Max on finite sets have been introduced (theory
  2433 Finite_Set);
  2434 
  2435 * attribute [symmetric] now works for relations as well; it turns
  2436 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2437 
  2438 * induct over a !!-quantified statement (say !!x1..xn):
  2439   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2440 
  2441 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2442 %x. None. Warning: empty_def now refers to the previously hidden definition
  2443 of the empty set.
  2444 
  2445 * Algebra: formalization of classical algebra.  Intended as base for
  2446 any algebraic development in Isabelle.  Currently covers group theory
  2447 (up to Sylow's theorem) and ring theory (Universal Property of
  2448 Univariate Polynomials).  Contributions welcome;
  2449 
  2450 * GroupTheory: deleted, since its material has been moved to Algebra;
  2451 
  2452 * Complex: new directory of the complex numbers with numeric constants,
  2453 nonstandard complex numbers, and some complex analysis, standard and
  2454 nonstandard (Jacques Fleuriot);
  2455 
  2456 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2457 
  2458 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2459 Fleuriot);
  2460 
  2461 * Real/HahnBanach: updated and adapted to locales;
  2462 
  2463 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2464 Gray and Kramer);
  2465 
  2466 * UNITY: added the Meier-Sanders theory of progress sets;
  2467 
  2468 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2469 as abstract algorithms, instantiated to the JVM;
  2470 
  2471 * Bali: Java source language formalization. Type system, operational
  2472 semantics, axiomatic semantics. Supported language features:
  2473 classes, interfaces, objects,virtual methods, static methods,
  2474 static/instance fields, arrays, access modifiers, definite
  2475 assignment, exceptions.
  2476 
  2477 
  2478 *** ZF ***
  2479 
  2480 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2481 universe, etc.);
  2482 
  2483 * Main ZF: virtually all theories converted to new-style format;
  2484 
  2485 
  2486 *** ML ***
  2487 
  2488 * Pure: Tactic.prove provides sane interface for internal proofs;
  2489 omits the infamous "standard" operation, so this is more appropriate
  2490 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2491 
  2492 * Pure: improved error reporting of simprocs;
  2493 
  2494 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2495 up simprocs;
  2496 
  2497 
  2498 *** Document preparation ***
  2499 
  2500 * uses \par instead of \\ for line breaks in theory text. This may
  2501 shift some page breaks in large documents. To get the old behaviour
  2502 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2503 
  2504 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2505 other packages
  2506 
  2507 * \<euro> now needs package babel/greek instead of marvosym (which
  2508 broke \Rightarrow)
  2509 
  2510 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2511 textcomp package)
  2512 
  2513 
  2514 
  2515 New in Isabelle2002 (March 2002)
  2516 --------------------------------
  2517 
  2518 *** Document preparation ***
  2519 
  2520 * greatly simplified document preparation setup, including more
  2521 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2522 instructive isatool mkdir; users should basically be able to get
  2523 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2524 users may run a separate document processing stage manually like this:
  2525 "isatool usedir -D output HOL Test && isatool document Test/output";
  2526 
  2527 * theory dependency graph may now be incorporated into documents;
  2528 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2529 with \includegraphics of LaTeX;
  2530 
  2531 * proper spacing of consecutive markup elements, especially text
  2532 blocks after section headings;
  2533 
  2534 * support bold style (for single symbols only), input syntax is like
  2535 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2536 
  2537 * \<bullet> is now output as bold \cdot by default, which looks much
  2538 better in printed text;
  2539 
  2540 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2541 note that these symbols are currently unavailable in Proof General /
  2542 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2543 
  2544 * isatool latex no longer depends on changed TEXINPUTS, instead
  2545 isatool document copies the Isabelle style files to the target
  2546 location;
  2547 
  2548 
  2549 *** Isar ***
  2550 
  2551 * Pure/Provers: improved proof by cases and induction;
  2552   - 'case' command admits impromptu naming of parameters (such as
  2553     "case (Suc n)");
  2554   - 'induct' method divinates rule instantiation from the inductive
  2555     claim; no longer requires excessive ?P bindings for proper
  2556     instantiation of cases;
  2557   - 'induct' method properly enumerates all possibilities of set/type
  2558     rules; as a consequence facts may be also passed through *type*
  2559     rules without further ado;
  2560   - 'induct' method now derives symbolic cases from the *rulified*
  2561     rule (before it used to rulify cases stemming from the internal
  2562     atomized version); this means that the context of a non-atomic
  2563     statement becomes is included in the hypothesis, avoiding the
  2564     slightly cumbersome show "PROP ?case" form;
  2565   - 'induct' may now use elim-style induction rules without chaining
  2566     facts, using ``missing'' premises from the goal state; this allows
  2567     rules stemming from inductive sets to be applied in unstructured
  2568     scripts, while still benefitting from proper handling of non-atomic
  2569     statements; NB: major inductive premises need to be put first, all
  2570     the rest of the goal is passed through the induction;
  2571   - 'induct' proper support for mutual induction involving non-atomic
  2572     rule statements (uses the new concept of simultaneous goals, see
  2573     below);
  2574   - append all possible rule selections, but only use the first
  2575     success (no backtracking);
  2576   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2577   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2578   - added 'print_induct_rules' (covered by help item in recent Proof
  2579     General versions);
  2580   - moved induct/cases attributes to Pure, methods to Provers;
  2581   - generic method setup instantiated for FOL and HOL;
  2582 
  2583 * Pure: support multiple simultaneous goal statements, for example
  2584 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2585 meta-level mechanism, this acts as if several individual goals had
  2586 been stated separately; in particular common proof methods need to be
  2587 repeated in order to cover all claims; note that a single elimination
  2588 step is *not* sufficient to establish the two conjunctions, so this
  2589 fails:
  2590 
  2591   assume "A & B" then have A and B ..   (*".." fails*)
  2592 
  2593 better use "obtain" in situations as above; alternative refer to
  2594 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2595 
  2596 * Pure: proper integration with ``locales''; unlike the original
  2597 version by Florian Kammller, Isar locales package high-level proof
  2598 contexts rather than raw logical ones (e.g. we admit to include
  2599 attributes everywhere); operations on locales include merge and
  2600 rename; support for implicit arguments (``structures''); simultaneous
  2601 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2602 some examples;
  2603 
  2604 * Pure: the following commands have been ``localized'', supporting a
  2605 target locale specification "(in name)": 'lemma', 'theorem',
  2606 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2607 stored both within the locale and at the theory level (exported and
  2608 qualified by the locale name);
  2609 
  2610 * Pure: theory goals may now be specified in ``long'' form, with
  2611 ad-hoc contexts consisting of arbitrary locale elements. for example
  2612 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2613 definitions may be given, too); the result is a meta-level rule with
  2614 the context elements being discharged in the obvious way;
  2615 
  2616 * Pure: new proof command 'using' allows to augment currently used
  2617 facts after a goal statement ('using' is syntactically analogous to
  2618 'apply', but acts on the goal's facts only); this allows chained facts
  2619 to be separated into parts given before and after a claim, as in
  2620 ``from a and b have C using d and e <proof>'';
  2621 
  2622 * Pure: renamed "antecedent" case to "rule_context";
  2623 
  2624 * Pure: new 'judgment' command records explicit information about the
  2625 object-logic embedding (used by several tools internally); no longer
  2626 use hard-wired "Trueprop";
  2627 
  2628 * Pure: added 'corollary' command;
  2629 
  2630 * Pure: fixed 'token_translation' command;
  2631 
  2632 * Pure: removed obsolete 'exported' attribute;
  2633 
  2634 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2635 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2636 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2637 
  2638 * Pure: method 'atomize' presents local goal premises as object-level
  2639 statements (atomic meta-level propositions); setup controlled via
  2640 rewrite rules declarations of 'atomize' attribute; example
  2641 application: 'induct' method with proper rule statements in improper
  2642 proof *scripts*;
  2643 
  2644 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2645 now consider the syntactic context of assumptions, giving a better
  2646 chance to get type-inference of the arguments right (this is
  2647 especially important for locales);
  2648 
  2649 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2650 mode;
  2651 
  2652 * Pure/obtain: the formal conclusion "thesis", being marked as
  2653 ``internal'', may no longer be reference directly in the text;
  2654 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2655 situations;
  2656 
  2657 * Pure: generic 'sym' attribute which declares a rule both as pure
  2658 'elim?' and for the 'symmetric' operation;
  2659 
  2660 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2661 text; the fixed correlation with particular command syntax has been
  2662 discontinued;
  2663 
  2664 * Pure: new method 'rules' is particularly well-suited for proof
  2665 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2666 but often produces more compact proof terms with less detours;
  2667 
  2668 * Pure/Provers/classical: simplified integration with pure rule
  2669 attributes and methods; the classical "intro?/elim?/dest?"
  2670 declarations coincide with the pure ones; the "rule" method no longer
  2671 includes classically swapped intros; "intro" and "elim" methods no
  2672 longer pick rules from the context; also got rid of ML declarations
  2673 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2674 INCOMPATIBILITY;
  2675 
  2676 * Provers/classical: attribute 'swapped' produces classical inversions
  2677 of introduction rules;
  2678 
  2679 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2680 rules instead of full simplifier context; 'iff' attribute handles
  2681 conditional rules;
  2682 
  2683 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2684 
  2685 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2686 "(permissive)" option to recover old behavior;
  2687 
  2688 * HOL: 'inductive' no longer features separate (collective) attributes
  2689 for 'intros' (was found too confusing);
  2690 
  2691 * HOL: properly declared induction rules less_induct and
  2692 wf_induct_rule;
  2693 
  2694 
  2695 *** HOL ***
  2696 
  2697 * HOL: moved over to sane numeral syntax; the new policy is as
  2698 follows:
  2699 
  2700   - 0 and 1 are polymorphic constants, which are defined on any
  2701   numeric type (nat, int, real etc.);
  2702 
  2703   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2704   binary representation internally;
  2705 
  2706   - type nat has special constructor Suc, and generally prefers Suc 0
  2707   over 1::nat and Suc (Suc 0) over 2::nat;
  2708 
  2709 This change may cause significant problems of INCOMPATIBILITY; here
  2710 are some hints on converting existing sources:
  2711 
  2712   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2713   entities, so expressions involving "-" (unary or binary minus) need
  2714   to be spaced properly;
  2715 
  2716   - existing occurrences of "1" may need to be constraint "1::nat" or
  2717   even replaced by Suc 0; similar for old "2";
  2718 
  2719   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2720 
  2721   - remove all special provisions on numerals in proofs;
  2722 
  2723 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2724 representation (depends on bin_arith_simps in the default context);
  2725 
  2726 * HOL: symbolic syntax for x^2 (numeral 2);
  2727 
  2728 * HOL: the class of all HOL types is now called "type" rather than
  2729 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2730 in axclass/classes, instance/arities, and (usually rare) occurrences
  2731 in typings (of consts etc.); internally the class is called
  2732 "HOL.type", ML programs should refer to HOLogic.typeS;
  2733 
  2734 * HOL/record package improvements:
  2735   - new derived operations "fields" to build a partial record section,
  2736     "extend" to promote a fixed record to a record scheme, and
  2737     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2738     declared as simp by default;
  2739   - shared operations ("more", "fields", etc.) now need to be always
  2740     qualified) --- potential INCOMPATIBILITY;
  2741   - removed "make_scheme" operations (use "make" with "extend") --
  2742     INCOMPATIBILITY;
  2743   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2744   - provides cases/induct rules for use with corresponding Isar
  2745     methods (for concrete records, record schemes, concrete more
  2746     parts, and schematic more parts -- in that order);
  2747   - internal definitions directly based on a light-weight abstract
  2748     theory of product types over typedef rather than datatype;
  2749 
  2750 * HOL: generic code generator for generating executable ML code from
  2751 specifications; specific support for HOL constructs such as inductive
  2752 datatypes and sets, as well as recursive functions; can be invoked
  2753 via 'generate_code' theory section;
  2754 
  2755 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2756 
  2757 * HOL: consolidated and renamed several theories.  In particular:
  2758         Ord.thy has been absorbed into HOL.thy
  2759         String.thy has been absorbed into List.thy
  2760 
  2761 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2762 (beware of argument permutation!);
  2763 
  2764 * HOL: linorder_less_split superseded by linorder_cases;
  2765 
  2766 * HOL/List: "nodups" renamed to "distinct";
  2767 
  2768 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2769 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2770   - Ex_def has changed, now need to use some_eq_ex
  2771 
  2772 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2773 in this (rare) case use:
  2774 
  2775   delSWrapper "split_all_tac"
  2776   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2777 
  2778 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2779 MAY FAIL;
  2780 
  2781 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2782 Isabelle's type classes, ^ on functions and relations has too general
  2783 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2784 necessary to attach explicit type constraints;
  2785 
  2786 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2787 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2788 renamed accordingly (eg "compI" -> "rel_compI").
  2789 
  2790 * HOL: syntax translations now work properly with numerals and records
  2791 expressions;
  2792 
  2793 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2794 of "lam" -- INCOMPATIBILITY;
  2795 
  2796 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2797 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2798 renamed "Product_Type.unit";
  2799 
  2800 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2801 
  2802 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2803 the "cases" method);
  2804 
  2805 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2806 Florian Kammller);
  2807 
  2808 * HOL/IMP: updated and converted to new-style theory format; several
  2809 parts turned into readable document, with proper Isar proof texts and
  2810 some explanations (by Gerwin Klein);
  2811 
  2812 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2813 
  2814 * HOL-Hyperreal is now a logic image;
  2815 
  2816 
  2817 *** HOLCF ***
  2818 
  2819 * Isar: consts/constdefs supports mixfix syntax for continuous
  2820 operations;
  2821 
  2822 * Isar: domain package adapted to new-style theory format, e.g. see
  2823 HOLCF/ex/Dnat.thy;
  2824 
  2825 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2826 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2827 lift.induct_tac, always use UU instead of Undef;
  2828 
  2829 * HOLCF/IMP: updated and converted to new-style theory;
  2830 
  2831 
  2832 *** ZF ***
  2833 
  2834 * Isar: proper integration of logic-specific tools and packages,
  2835 including theory commands '(co)inductive', '(co)datatype',
  2836 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2837 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2838 
  2839 * theory Main no longer includes AC; for the Axiom of Choice, base
  2840 your theory on Main_ZFC;
  2841 
  2842 * the integer library now covers quotients and remainders, with many
  2843 laws relating division to addition, multiplication, etc.;
  2844 
  2845 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2846 typeless version of the formalism;
  2847 
  2848 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2849 format;
  2850 
  2851 * ZF/Induct: new directory for examples of inductive definitions,
  2852 including theory Multiset for multiset orderings; converted to
  2853 new-style theory format;
  2854 
  2855 * ZF: many new theorems about lists, ordinals, etc.;
  2856 
  2857 
  2858 *** General ***
  2859 
  2860 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2861 variable proof controls level of detail: 0 = no proofs (only oracle
  2862 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2863 also ref manual for further ML interfaces;
  2864 
  2865 * Pure/axclass: removed obsolete ML interface
  2866 goal_subclass/goal_arity;
  2867 
  2868 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2869 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2870 separate tokens, so expressions involving minus need to be spaced
  2871 properly;
  2872 
  2873 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2874 rather than "infixl" or "infixr";
  2875 
  2876 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2877 sort constraint specifications in type inference; e.g. "x::_::foo"
  2878 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2879 type variable);
  2880 
  2881 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2882 control output of nested => (types); the default behavior is
  2883 "type_brackets";
  2884 
  2885 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2886 tokens into AST constants;
  2887 
  2888 * Pure/syntax: prefer later declarations of translations and print
  2889 translation functions; potential INCOMPATIBILITY: need to reverse
  2890 multiple declarations for same syntax element constant;
  2891 
  2892 * Pure/show_hyps reset by default (in accordance to existing Isar
  2893 practice);
  2894 
  2895 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2896 addSafter;
  2897 
  2898 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2899 as well;
  2900 
  2901 * system: tested support for MacOS X; should be able to get Isabelle +
  2902 Proof General to work in a plain Terminal after installing Poly/ML
  2903 (e.g. from the Isabelle distribution area) and GNU bash alone
  2904 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2905 support requires further installations, e.g. from
  2906 http://fink.sourceforge.net/);
  2907 
  2908 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2909 
  2910 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2911 of 40 MB), cf. ML_OPTIONS;
  2912 
  2913 * system: Proof General keywords specification is now part of the
  2914 Isabelle distribution (see etc/isar-keywords.el);
  2915 
  2916 * system: support for persistent Proof General sessions (refrain from
  2917 outdating all loaded theories on startup); user may create writable
  2918 logic images like this: ``isabelle -q HOL Test'';
  2919 
  2920 * system: smart selection of Isabelle process versus Isabelle
  2921 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2922 run both "isabelle" and "Isabelle" even if file names are badly
  2923 damaged (executable inspects the case of the first letter of its own
  2924 name); added separate "isabelle-process" and "isabelle-interface";
  2925 
  2926 * system: refrain from any attempt at filtering input streams; no
  2927 longer support ``8bit'' encoding of old isabelle font, instead proper
  2928 iso-latin characters may now be used; the related isatools
  2929 "symbolinput" and "nonascii" have disappeared as well;
  2930 
  2931 * system: removed old "xterm" interface (the print modes "xterm" and
  2932 "xterm_color" are still available for direct use in a suitable
  2933 terminal);
  2934 
  2935 
  2936 
  2937 New in Isabelle99-2 (February 2001)
  2938 -----------------------------------
  2939 
  2940 *** Overview of INCOMPATIBILITIES ***
  2941 
  2942 * HOL: please note that theories in the Library and elsewhere often use the
  2943 new-style (Isar) format; to refer to their theorems in an ML script you must
  2944 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2945 
  2946 * HOL: inductive package no longer splits induction rule aggressively,
  2947 but only as far as specified by the introductions given; the old
  2948 format may be recovered via ML function complete_split_rule or attribute
  2949 'split_rule (complete)';
  2950 
  2951 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2952 gfp_Tarski to gfp_unfold;
  2953 
  2954 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2955 
  2956 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2957 relation); infix "^^" has been renamed "``"; infix "``" has been
  2958 renamed "`"; "univalent" has been renamed "single_valued";
  2959 
  2960 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2961 operation;
  2962 
  2963 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2964 
  2965 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2966 
  2967 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2968 consequence, it is no longer monotonic wrt. the local goal context
  2969 (which is now passed through the inductive cases);
  2970 
  2971 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2972 \<gg> to \<ggreater>;
  2973 
  2974 
  2975 *** Document preparation ***
  2976 
  2977 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2978 available: are "it" for near math-mode best-style output, "sl" for
  2979 slanted text style, and "tt" for plain type-writer; if no
  2980 \isabellestyle command is given, output is according to slanted
  2981 type-writer);
  2982 
  2983 * support sub/super scripts (for single symbols only), input syntax is
  2984 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2985 
  2986 * some more standard symbols; see Appendix A of the system manual for
  2987 the complete list of symbols defined in isabellesym.sty;
  2988 
  2989 * improved isabelle style files; more abstract symbol implementation
  2990 (should now use \isamath{...} and \isatext{...} in custom symbol
  2991 definitions);
  2992 
  2993 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2994 state; Note that presentation of goal states does not conform to
  2995 actual human-readable proof documents.  Please do not include goal
  2996 states into document output unless you really know what you are doing!
  2997 
  2998 * proper indentation of antiquoted output with proportional LaTeX
  2999 fonts;
  3000 
  3001 * no_document ML operator temporarily disables LaTeX document
  3002 generation;
  3003 
  3004 * isatool unsymbolize tunes sources for plain ASCII communication;
  3005 
  3006 
  3007 *** Isar ***
  3008 
  3009 * Pure: Isar now suffers initial goal statements to contain unbound
  3010 schematic variables (this does not conform to actual readable proof
  3011 documents, due to unpredictable outcome and non-compositional proof
  3012 checking); users who know what they are doing may use schematic goals
  3013 for Prolog-style synthesis of proven results;
  3014 
  3015 * Pure: assumption method (an implicit finishing) now handles actual
  3016 rules as well;
  3017 
  3018 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3019 initial goal, declare "that" only as Pure intro (only for single
  3020 steps); the "that" rule assumption may now be involved in implicit
  3021 finishing, thus ".." becomes a feasible for trivial obtains;
  3022 
  3023 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3024 instance proofs may be performed by "..";
  3025 
  3026 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3027 statements as well;
  3028 
  3029 * Pure: more robust selection of calculational rules;
  3030 
  3031 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3032 rule (as well as the assumption rule);
  3033 
  3034 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3035 lemmas, using the graph browser tool;
  3036 
  3037 * Pure: predict failure of "show" in interactive mode;
  3038 
  3039 * Pure: 'thms_containing' now takes actual terms as arguments;
  3040 
  3041 * HOL: improved method 'induct' --- now handles non-atomic goals
  3042 (potential INCOMPATIBILITY); tuned error handling;
  3043 
  3044 * HOL: cases and induct rules now provide explicit hints about the
  3045 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3046 any remaining facts are inserted into the goal verbatim;
  3047 
  3048 * HOL: local contexts (aka cases) may now contain term bindings as
  3049 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3050 the result to be shown in each case;
  3051 
  3052 * HOL: added 'recdef_tc' command;
  3053 
  3054 * isatool convert assists in eliminating legacy ML scripts;
  3055 
  3056 
  3057 *** HOL ***
  3058 
  3059 * HOL/Library: a collection of generic theories to be used together
  3060 with main HOL; the theory loader path already includes this directory
  3061 by default; the following existing theories have been moved here:
  3062 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3063 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3064 
  3065 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3066 modelling and verification task performed in Isabelle/HOL +
  3067 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3068 
  3069 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3070 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3071 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3072 'domain', this makes the theory consistent with mathematical
  3073 literature;
  3074 
  3075 * HOL basics: added overloaded operations "inverse" and "divide"
  3076 (infix "/"), syntax for generic "abs" operation, generic summation
  3077 operator \<Sum>;
  3078 
  3079 * HOL/typedef: simplified package, provide more useful rules (see also
  3080 HOL/subset.thy);
  3081 
  3082 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3083 now expressed as a proper nested rule (old-style tactic scripts may
  3084 require atomize_strip_tac to cope with non-atomic premises);
  3085 
  3086 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3087 to "split_conv" (old name still available for compatibility);
  3088 
  3089 * HOL: improved concrete syntax for strings (e.g. allows translation
  3090 rules with string literals);
  3091 
  3092 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3093  and Fleuriot's mechanization of analysis, including the transcendental
  3094  functions for the reals;
  3095 
  3096 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3097 
  3098 
  3099 *** CTT ***
  3100 
  3101 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3102 "lam" is displayed as TWO lambda-symbols
  3103 
  3104 * CTT: theory Main now available, containing everything (that is, Bool
  3105 and Arith);
  3106 
  3107 
  3108 *** General ***
  3109 
  3110 * Pure: the Simplifier has been implemented properly as a derived rule
  3111 outside of the actual kernel (at last!); the overall performance
  3112 penalty in practical applications is about 50%, while reliability of
  3113 the Isabelle inference kernel has been greatly improved;
  3114 
  3115 * print modes "brackets" and "no_brackets" control output of nested =>
  3116 (types) and ==> (props); the default behaviour is "brackets";
  3117 
  3118 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3119 as assumptions as well;
  3120 
  3121 * system: support Poly/ML 4.0;
  3122 
  3123 * system: isatool install handles KDE version 1 or 2;
  3124 
  3125 
  3126 
  3127 New in Isabelle99-1 (October 2000)
  3128 ----------------------------------
  3129 
  3130 *** Overview of INCOMPATIBILITIES ***
  3131 
  3132 * HOL: simplification of natural numbers is much changed; to partly
  3133 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3134 issue the following ML commands:
  3135 
  3136   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3137   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3138 
  3139 * HOL: simplification no longer dives into case-expressions; this is
  3140 controlled by "t.weak_case_cong" for each datatype t;
  3141 
  3142 * HOL: nat_less_induct renamed to less_induct;
  3143 
  3144 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3145 fixsome to patch .thy and .ML sources automatically;
  3146 
  3147   select_equality  -> some_equality
  3148   select_eq_Ex     -> some_eq_ex
  3149   selectI2EX       -> someI2_ex
  3150   selectI2         -> someI2
  3151   selectI          -> someI
  3152   select1_equality -> some1_equality
  3153   Eps_sym_eq       -> some_sym_eq_trivial
  3154   Eps_eq           -> some_eq_trivial
  3155 
  3156 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3157 
  3158 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3159 instead);
  3160 
  3161 * HOL: the recursion equations generated by 'recdef' are now called
  3162 f.simps instead of f.rules;
  3163 
  3164 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3165 
  3166 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3167 sometimes be needed;
  3168 
  3169 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3170 
  3171 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3172 
  3173 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3174 product is now "<*>" instead of "Times"; the lexicographic product is
  3175 now "<*lex*>" instead of "**";
  3176 
  3177 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3178 of main HOL, but was unused); better use HOL's datatype package;
  3179 
  3180 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3181 the old syntax may be recovered as follows:
  3182 
  3183   syntax (symbols)
  3184     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3185       (infixl "\\<oplus>" 100)
  3186 
  3187 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3188 
  3189 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3190 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3191 internally;
  3192 
  3193 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3194 changed from A/r to A//r;
  3195 
  3196 * ZF: new treatment of arithmetic (nat & int) may break some old
  3197 proofs;
  3198 
  3199 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3200 rulify -> rule_format, elimify -> elim_format, ...);
  3201 
  3202 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3203 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3204 should have to change intro!! to intro? only); replaced "delrule" by
  3205 "rule del";
  3206 
  3207 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3208 
  3209 * Provers: strengthened force_tac by using new first_best_tac;
  3210 
  3211 * LaTeX document preparation: several changes of isabelle.sty (see
  3212 lib/texinputs);
  3213 
  3214 
  3215 *** Document preparation ***
  3216 
  3217 * formal comments (text blocks etc.) in new-style theories may now
  3218 contain antiquotations of thm/prop/term/typ/text to be presented
  3219 according to latex print mode; concrete syntax is like this:
  3220 @{term[show_types] "f(x) = a + x"};
  3221 
  3222 * isatool mkdir provides easy setup of Isabelle session directories,
  3223 including proper document sources;
  3224 
  3225 * generated LaTeX sources are now deleted after successful run
  3226 (isatool document -c); may retain a copy somewhere else via -D option
  3227 of isatool usedir;
  3228 
  3229 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3230 style files, achieving self-contained LaTeX sources and simplifying
  3231 LaTeX debugging;
  3232 
  3233 * old-style theories now produce (crude) LaTeX output as well;
  3234 
  3235 * browser info session directories are now self-contained (may be put
  3236 on WWW server seperately); improved graphs of nested sessions; removed
  3237 graph for 'all sessions';
  3238 
  3239 * several improvements in isabelle style files; \isabellestyle{it}
  3240 produces fake math mode output; \isamarkupheader is now \section by
  3241 default; see lib/texinputs/isabelle.sty etc.;
  3242 
  3243 
  3244 *** Isar ***
  3245 
  3246 * Isar/Pure: local results and corresponding term bindings are now
  3247 subject to Hindley-Milner polymorphism (similar to ML); this
  3248 accommodates incremental type-inference very nicely;
  3249 
  3250 * Isar/Pure: new derived language element 'obtain' supports
  3251 generalized existence reasoning;
  3252 
  3253 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3254 support accumulation of results, without applying any rules yet;
  3255 useful to collect intermediate results without explicit name
  3256 references, and for use with transitivity rules with more than 2
  3257 premises;
  3258 
  3259 * Isar/Pure: scalable support for case-analysis type proofs: new
  3260 'case' language element refers to local contexts symbolically, as
  3261 produced by certain proof methods; internally, case names are attached
  3262 to theorems as "tags";
  3263 
  3264 * Isar/Pure: theory command 'hide' removes declarations from
  3265 class/type/const name spaces;
  3266 
  3267 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3268 indicate potential overloading;
  3269 
  3270 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3271 
  3272 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3273 "{a,b,c}" instead of {a,b,c};
  3274 
  3275 * Isar/Pure now provides its own version of intro/elim/dest
  3276 attributes; useful for building new logics, but beware of confusion
  3277 with the version in Provers/classical;
  3278 
  3279 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3280 case name 'antecedent';
  3281 
  3282 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3283 to the current context is now done automatically);
  3284 
  3285 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3286 for definining proof methods in ML;
  3287 
  3288 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3289 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3290 most cases, one should have to change intro!! to intro? only);
  3291 replaced "delrule" by "rule del";
  3292 
  3293 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3294 'symmetric' attribute (the latter supercedes [RS sym]);
  3295 
  3296 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3297 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3298 well (including splits);
  3299 
  3300 * Isar/Provers: Simplifier and Classical methods now support all kind
  3301 of modifiers used in the past, including 'cong', 'iff', etc.
  3302 
  3303 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3304 of Simplifier and Classical reasoner);
  3305 
  3306 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3307 now support named cases; major packages (inductive, datatype, primrec,
  3308 recdef) support case names and properly name parameters;
  3309 
  3310 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3311 monotonicity conditions are extracted to be proven at end of
  3312 calculations;
  3313 
  3314 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3315 method anyway;
  3316 
  3317 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3318 split_if split_if_asm; datatype package provides theorems foo.splits =
  3319 foo.split foo.split_asm for each datatype;
  3320 
  3321 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3322 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3323 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3324 use "(cases (simplified))" method in proper proof texts);
  3325 
  3326 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3327 
  3328 * Isar: names of theorems etc. may be natural numbers as well;
  3329 
  3330 * Isar: 'pr' command: optional arguments for goals_limit and
  3331 ProofContext.prems_limit; no longer prints theory contexts, but only
  3332 proof states;
  3333 
  3334 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3335 additional print modes to be specified; e.g. "pr(latex)" will print
  3336 proof state according to the Isabelle LaTeX style;
  3337 
  3338 * Isar: improved support for emulating tactic scripts, including proof
  3339 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3340 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3341 (for HOL datatypes);
  3342 
  3343 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3344 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3345 'proof method scripts' have to be in depth-first order;
  3346 
  3347 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3348 
  3349 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3350 should instead use individual commands for printing items
  3351 (print_commands, print_methods etc.);
  3352 
  3353 * Isar: added 'nothing' --- the empty list of theorems;
  3354 
  3355 
  3356 *** HOL ***
  3357 
  3358 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3359 corresponding virtual machine and a specification of its bytecode
  3360 verifier and a lightweight bytecode verifier, including proofs of
  3361 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3362 Cornelia Pusch (see also the homepage of project Bali at
  3363 http://isabelle.in.tum.de/Bali/);
  3364 
  3365 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3366 Clemens Ballarin;
  3367 
  3368 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3369 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3370 Rasmussen;
  3371 
  3372 * HOL/Lattice: fundamental concepts of lattice theory and order
  3373 structures, including duals, properties of bounds versus algebraic
  3374 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3375 Theorem for complete lattices etc.; may also serve as a demonstration
  3376 for abstract algebraic reasoning using axiomatic type classes, and
  3377 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3378 
  3379 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3380 von Oheimb;
  3381 
  3382 * HOL/IMPP: extension of IMP with local variables and mutually
  3383 recursive procedures, by David von Oheimb;
  3384 
  3385 * HOL/Lambda: converted into new-style theory and document;
  3386 
  3387 * HOL/ex/Multiquote: example of multiple nested quotations and
  3388 anti-quotations -- basically a generalized version of de-Bruijn
  3389 representation; very useful in avoiding lifting of operations;
  3390 
  3391 * HOL/record: added general record equality rule to simpset; fixed
  3392 select-update simplification procedure to handle extended records as
  3393 well; admit "r" as field name;
  3394 
  3395 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3396 other numeric types and also as the identity of groups, rings, etc.;
  3397 
  3398 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3399 Types nat and int belong to this axclass;
  3400 
  3401 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3402    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3403    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3404   two terms #m*u and #n*u are replaced by #(m+n)*u
  3405     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3406   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3407     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3408 
  3409 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3410 powerful prover for predicate logic but knows nothing of clasets; see
  3411 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3412 
  3413 * HOL: new version of "case_tac" subsumes both boolean case split and
  3414 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3415 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3416 
  3417 * HOL: simplification no longer dives into case-expressions: only the
  3418 selector expression is simplified, but not the remaining arms; to
  3419 enable full simplification of case-expressions for datatype t, you may
  3420 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3421 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3422 
  3423 * HOL/recdef: the recursion equations generated by 'recdef' for
  3424 function 'f' are now called f.simps instead of f.rules; if all
  3425 termination conditions are proved automatically, these simplification
  3426 rules are added to the simpset, as in primrec; rules may be named
  3427 individually as well, resulting in a separate list of theorems for
  3428 each equation;
  3429 
  3430 * HOL/While is a new theory that provides a while-combinator. It
  3431 permits the definition of tail-recursive functions without the
  3432 provision of a termination measure. The latter is necessary once the
  3433 invariant proof rule for while is applied.
  3434 
  3435 * HOL: new (overloaded) notation for the set of elements below/above
  3436 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3437 
  3438 * HOL: theorems impI, allI, ballI bound as "strip";
  3439 
  3440 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3441 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3442 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3443 
  3444 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3445 
  3446 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3447 main HOL, but was unused);
  3448 
  3449 * HOL: fewer consts declared as global (e.g. have to refer to
  3450 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3451 
  3452 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3453 in case of overlap with user translations (e.g. judgements over
  3454 tuples); (note that the underlying logical represenation is still
  3455 bogus);
  3456 
  3457 
  3458 *** ZF ***
  3459 
  3460 * ZF: simplification automatically cancels common terms in arithmetic
  3461 expressions over nat and int;
  3462 
  3463 * ZF: new treatment of nat to minimize type-checking: all operators
  3464 coerce their operands to a natural number using the function natify,
  3465 making the algebraic laws unconditional;
  3466 
  3467 * ZF: as above, for int: operators coerce their operands to an integer
  3468 using the function intify;
  3469 
  3470 * ZF: the integer library now contains many of the usual laws for the
  3471 orderings, including $<=, and monotonicity laws for $+ and $*;
  3472 
  3473 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3474 simplification;
  3475 
  3476 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3477 to the simplifier and classical reasoner simultaneously;
  3478 
  3479 
  3480 *** General ***
  3481 
  3482 * Provers: blast_tac now handles actual object-logic rules as
  3483 assumptions; note that auto_tac uses blast_tac internally as well;
  3484 
  3485 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3486 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3487 
  3488 * Provers: delrules now handles destruct rules as well (no longer need
  3489 explicit make_elim);
  3490 
  3491 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3492   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3493 use instead the strong form,
  3494   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3495 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3496 from destruct-rules;
  3497 
  3498 * Provers: Simplifier.easy_setup provides a fast path to basic
  3499 Simplifier setup for new object-logics;
  3500 
  3501 * Pure: AST translation rules no longer require constant head on LHS;
  3502 
  3503 * Pure: improved name spaces: ambiguous output is qualified; support
  3504 for hiding of names;
  3505 
  3506 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3507 XSYMBOL_HOME; no longer need to do manual configuration in most
  3508 situations;
  3509 
  3510 * system: compression of ML heaps images may now be controlled via -c
  3511 option of isabelle and isatool usedir (currently only observed by
  3512 Poly/ML);
  3513 
  3514 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3515 useful for remote X11);
  3516 
  3517 * system: provide TAGS file for Isabelle sources;
  3518 
  3519 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3520 order;
  3521 
  3522 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3523 timing flag supersedes proof_timing and Toplevel.trace;
  3524 
  3525 * ML: new combinators |>> and |>>> for incremental transformations
  3526 with secondary results (e.g. certain theory extensions):
  3527 
  3528 * ML: PureThy.add_defs gets additional argument to indicate potential
  3529 overloading (usually false);
  3530 
  3531 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3532 results;
  3533 
  3534 
  3535 
  3536 New in Isabelle99 (October 1999)
  3537 --------------------------------
  3538 
  3539 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3540 
  3541 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3542 are no longer simplified.  (This allows the simplifier to unfold recursive
  3543 functional programs.)  To restore the old behaviour, declare
  3544 
  3545     Delcongs [if_weak_cong];
  3546 
  3547 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3548 complement;
  3549 
  3550 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3551 
  3552 * HOL/datatype: mutual_induct_tac no longer exists --
  3553   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3554 
  3555 * HOL/typedef: fixed type inference for representing set; type
  3556 arguments now have to occur explicitly on the rhs as type constraints;
  3557 
  3558 * ZF: The con_defs part of an inductive definition may no longer refer
  3559 to constants declared in the same theory;
  3560 
  3561 * HOL, ZF: the function mk_cases, generated by the inductive
  3562 definition package, has lost an argument.  To simplify its result, it
  3563 uses the default simpset instead of a supplied list of theorems.
  3564 
  3565 * HOL/List: the constructors of type list are now Nil and Cons;
  3566 
  3567 * Simplifier: the type of the infix ML functions
  3568         setSSolver addSSolver setSolver addSolver
  3569 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3570 for packaging solvers. A solver is created via
  3571         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3572 where the string argument is only a comment.
  3573 
  3574 
  3575 *** Proof tools ***
  3576 
  3577 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3578 decision procedure for linear arithmetic. Currently it is used for
  3579 types `nat', `int', and `real' in HOL (see below); it can, should and
  3580 will be instantiated for other types and logics as well.
  3581 
  3582 * The simplifier now accepts rewrite rules with flexible heads, eg
  3583      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3584   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3585   matching.
  3586 
  3587 
  3588 *** General ***
  3589 
  3590 * New Isabelle/Isar subsystem provides an alternative to traditional
  3591 tactical theorem proving; together with the ProofGeneral/isar user
  3592 interface it offers an interactive environment for developing human
  3593 readable proof documents (Isar == Intelligible semi-automated
  3594 reasoning); for further information see isatool doc isar-ref,
  3595 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3596 
  3597 * improved and simplified presentation of theories: better HTML markup
  3598 (including colors), graph views in several sizes; isatool usedir now
  3599 provides a proper interface for user theories (via -P option); actual
  3600 document preparation based on (PDF)LaTeX is available as well (for
  3601 new-style theories only); see isatool doc system for more information;
  3602 
  3603 * native support for Proof General, both for classic Isabelle and
  3604 Isabelle/Isar;
  3605 
  3606 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3607 using the graph browser tool;
  3608 
  3609 * Isabelle manuals now also available as PDF;
  3610 
  3611 * theory loader rewritten from scratch (may not be fully
  3612 bug-compatible); old loadpath variable has been replaced by show_path,
  3613 add_path, del_path, reset_path functions; new operations such as
  3614 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3615 isatool doc ref);
  3616 
  3617 * improved isatool install: option -k creates KDE application icon,
  3618 option -p DIR installs standalone binaries;
  3619 
  3620 * added ML_PLATFORM setting (useful for cross-platform installations);
  3621 more robust handling of platform specific ML images for SML/NJ;
  3622 
  3623 * the settings environment is now statically scoped, i.e. it is never
  3624 created again in sub-processes invoked from isabelle, isatool, or
  3625 Isabelle;
  3626 
  3627 * path element specification '~~' refers to '$ISABELLE_HOME';
  3628 
  3629 * in locales, the "assumes" and "defines" parts may be omitted if
  3630 empty;
  3631 
  3632 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3633 long arrows);
  3634 
  3635 * new print_mode "HTML";
  3636 
  3637 * new flag show_tags controls display of tags of theorems (which are
  3638 basically just comments that may be attached by some tools);
  3639 
  3640 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3641 mode and goal output format:
  3642 
  3643 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3644 244c244
  3645 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3646 ---
  3647 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3648 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3649 181c181
  3650 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3651 ---
  3652 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3653 
  3654 * function bind_thms stores lists of theorems (cf. bind_thm);
  3655 
  3656 * new shorthand tactics ftac, eatac, datac, fatac;
  3657 
  3658 * qed (and friends) now accept "" as result name; in that case the
  3659 theorem is not stored, but proper checks and presentation of the
  3660 result still apply;
  3661 
  3662 * theorem database now also indexes constants "Trueprop", "all",
  3663 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3664 
  3665 
  3666 *** HOL ***
  3667 
  3668 ** HOL arithmetic **
  3669 
  3670 * There are now decision procedures for linear arithmetic over nat and
  3671 int:
  3672 
  3673 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3674 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3675 are treated as atomic; subformulae not involving type `nat' or `int'
  3676 are ignored; quantified subformulae are ignored unless they are
  3677 positive universal or negative existential. The tactic has to be
  3678 invoked by hand and can be a little bit slow. In particular, the
  3679 running time is exponential in the number of occurrences of `min' and
  3680 `max', and `-' on `nat'.
  3681 
  3682 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3683 (negated) (in)equalities among the premises and the conclusion into
  3684 account (i.e. no compound formulae) and does not know about `min' and
  3685 `max', and `-' on `nat'. It is fast and is used automatically by the
  3686 simplifier.
  3687 
  3688 NB: At the moment, these decision procedures do not cope with mixed
  3689 nat/int formulae where the two parts interact, such as `m < n ==>
  3690 int(m) < int(n)'.
  3691 
  3692 * HOL/Numeral provides a generic theory of numerals (encoded
  3693 efficiently as bit strings); setup for types nat/int/real is in place;
  3694 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3695 int, existing theories and proof scripts may require a few additional
  3696 type constraints;
  3697 
  3698 * integer division and remainder can now be performed on constant
  3699 arguments;
  3700 
  3701 * many properties of integer multiplication, division and remainder
  3702 are now available;
  3703 
  3704 * An interface to the Stanford Validity Checker (SVC) is available through the
  3705 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3706 are proved automatically.  SVC must be installed separately, and its results
  3707 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3708 invocation of the underlying oracle).  For SVC see
  3709   http://verify.stanford.edu/SVC
  3710 
  3711 * IsaMakefile: the HOL-Real target now builds an actual image;
  3712 
  3713 
  3714 ** HOL misc **
  3715 
  3716 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3717 (in Isabelle/Isar) -- by Gertrud Bauer;
  3718 
  3719 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3720 analysis for assembly languages with subtypes;
  3721 
  3722 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3723 -- avoids syntactic ambiguities and treats state, transition, and
  3724 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3725 changed syntax and (many) tactics;
  3726 
  3727 * HOL/inductive: Now also handles more general introduction rules such
  3728   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3729   theorems are now maintained within the theory (maintained via the
  3730   "mono" attribute);
  3731 
  3732 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3733   (using function types) such as
  3734 
  3735   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3736 
  3737 * HOL/record: record_simproc (part of the default simpset) takes care
  3738 of selectors applied to updated records; record_split_tac is no longer
  3739 part of the default claset; update_defs may now be removed from the
  3740 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3741 
  3742   claset_ref () := claset() addSWrapper record_split_wrapper;
  3743   Delsimprocs [record_simproc]
  3744 
  3745 * HOL/typedef: fixed type inference for representing set; type
  3746 arguments now have to occur explicitly on the rhs as type constraints;
  3747 
  3748 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3749 names rather than an ML expression;
  3750 
  3751 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3752 supplied later.  Program schemes can be defined, such as
  3753     "While B C s = (if B s then While B C (C s) else s)"
  3754 where the well-founded relation can be chosen after B and C have been given.
  3755 
  3756 * HOL/List: the constructors of type list are now Nil and Cons;
  3757 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3758 course, ML tools referring to List.list.op # etc. have to be adapted;
  3759 
  3760 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3761 disabled by default; run isabelle with option -m HOL to get back to
  3762 the original Gordon/HOL-style output;
  3763 
  3764 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3765 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3766 
  3767 * HOL basic syntax simplified (more orthogonal): all variants of
  3768 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3769 Eps operator is provided as well: "SOME x. P[x]";
  3770 
  3771 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3772 
  3773 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3774 thus available for user theories;
  3775 
  3776 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3777 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3778 time;
  3779 
  3780 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3781 several times and then mp;
  3782 
  3783 
  3784 *** LK ***
  3785 
  3786 * the notation <<...>> is now available as a notation for sequences of
  3787 formulas;
  3788 
  3789 * the simplifier is now installed
  3790 
  3791 * the axiom system has been generalized (thanks to Soren Heilmann)
  3792 
  3793 * the classical reasoner now has a default rule database
  3794 
  3795 
  3796 *** ZF ***
  3797 
  3798 * new primrec section allows primitive recursive functions to be given
  3799 directly (as in HOL) over datatypes and the natural numbers;
  3800 
  3801 * new tactics induct_tac and exhaust_tac for induction (or case
  3802 analysis) over datatypes and the natural numbers;
  3803 
  3804 * the datatype declaration of type T now defines the recursor T_rec;
  3805 
  3806 * simplification automatically does freeness reasoning for datatype
  3807 constructors;
  3808 
  3809 * automatic type-inference, with AddTCs command to insert new
  3810 type-checking rules;
  3811 
  3812 * datatype introduction rules are now added as Safe Introduction rules
  3813 to the claset;
  3814 
  3815 * the syntax "if P then x else y" is now available in addition to
  3816 if(P,x,y);
  3817 
  3818 
  3819 *** Internal programming interfaces ***
  3820 
  3821 * tuned simplifier trace output; new flag debug_simp;
  3822 
  3823 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3824 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3825 
  3826 * AxClass.axclass_tac lost the theory argument;
  3827 
  3828 * tuned current_goals_markers semantics: begin / end goal avoids
  3829 printing empty lines;
  3830 
  3831 * removed prs and prs_fn hook, which was broken because it did not
  3832 include \n in its semantics, forcing writeln to add one
  3833 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3834 string -> unit if you really want to output text without newline;
  3835 
  3836 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3837 plain output, interface builders may have to enable 'isabelle_font'
  3838 mode to get Isabelle font glyphs as before;
  3839 
  3840 * refined token_translation interface; INCOMPATIBILITY: output length
  3841 now of type real instead of int;
  3842 
  3843 * theory loader actions may be traced via new ThyInfo.add_hook
  3844 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3845 your own database of information attached to *whole* theories -- as
  3846 opposed to intra-theory data slots offered via TheoryDataFun;
  3847 
  3848 * proper handling of dangling sort hypotheses (at last!);
  3849 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3850 extra sort hypotheses that can be witnessed from the type signature;
  3851 the force_strip_shyps flag is gone, any remaining shyps are simply
  3852 left in the theorem (with a warning issued by strip_shyps_warning);
  3853 
  3854 
  3855 
  3856 New in Isabelle98-1 (October 1998)
  3857 ----------------------------------
  3858 
  3859 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3860 
  3861 * several changes of automated proof tools;
  3862 
  3863 * HOL: major changes to the inductive and datatype packages, including
  3864 some minor incompatibilities of theory syntax;
  3865 
  3866 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3867 called `inj_on';
  3868 
  3869 * HOL: removed duplicate thms in Arith:
  3870   less_imp_add_less  should be replaced by  trans_less_add1
  3871   le_imp_add_le      should be replaced by  trans_le_add1
  3872 
  3873 * HOL: unary minus is now overloaded (new type constraints may be
  3874 required);
  3875 
  3876 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3877 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3878 now taken as an integer constant.
  3879 
  3880 * Pure: ML function 'theory_of' renamed to 'theory';
  3881 
  3882 
  3883 *** Proof tools ***
  3884 
  3885 * Simplifier:
  3886   1. Asm_full_simp_tac is now more aggressive.
  3887      1. It will sometimes reorient premises if that increases their power to
  3888         simplify.
  3889      2. It does no longer proceed strictly from left to right but may also
  3890         rotate premises to achieve further simplification.
  3891      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3892      old Asm_full_simp_tac in that it does not rotate premises.
  3893   2. The simplifier now knows a little bit about nat-arithmetic.
  3894 
  3895 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3896 allows for selected deletion of wrappers, by introduction of names for
  3897 wrapper functionals.  This implies that addbefore, addSbefore,
  3898 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3899 and that adding two tactics with the same name overwrites the first
  3900 one (emitting a warning).
  3901   type wrapper = (int -> tactic) -> (int -> tactic)
  3902   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3903   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3904   delWrapper, delSWrapper: claset *  string            -> claset
  3905   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3906 
  3907 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3908 semantics; addbefore now affects only the unsafe part of step_tac
  3909 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3910 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3911 by Force_tac;
  3912 
  3913 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3914 compWrapper; added safe wrapper (and access functions for it);
  3915 
  3916 * HOL/split_all_tac is now much faster and fails if there is nothing
  3917 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3918 and the names of the automatically generated variables have changed.
  3919 split_all_tac has moved within claset() from unsafe wrappers to safe
  3920 wrappers, which means that !!-bound variables are split much more
  3921 aggressively, and safe_tac and clarify_tac now split such variables.
  3922 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3923 Note: the same holds for record_split_tac, which does the job of
  3924 split_all_tac for record fields.
  3925 
  3926 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3927 permanently to the default simpset using Addsplits just like
  3928 Addsimps. They can be removed via Delsplits just like
  3929 Delsimps. Lower-case versions are also available.
  3930 
  3931 * HOL/Simplifier: The rule split_if is now part of the default
  3932 simpset. This means that the simplifier will eliminate all occurrences
  3933 of if-then-else in the conclusion of a goal. To prevent this, you can
  3934 either remove split_if completely from the default simpset by
  3935 `Delsplits [split_if]' or remove it in a specific call of the
  3936 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3937 other case splitting rules to/from the default simpset: every datatype
  3938 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3939 t is the name of the datatype).
  3940 
  3941 * Classical reasoner / Simplifier combination: new force_tac (and
  3942 derivatives Force_tac, force) combines rewriting and classical
  3943 reasoning (and whatever other tools) similarly to auto_tac, but is
  3944 aimed to solve the given subgoal completely.
  3945 
  3946 
  3947 *** General ***
  3948 
  3949 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3950 and `goalw': the theory is no longer needed as an explicit argument -
  3951 the current theory context is used; assumptions are no longer returned
  3952 at the ML-level unless one of them starts with ==> or !!; it is
  3953 recommended to convert to these new commands using isatool fixgoal
  3954 (backup your sources first!);
  3955 
  3956 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3957 the current theory context, and 'theory' to lookup stored theories;
  3958 
  3959 * new theory section 'locale' for declaring constants, assumptions and
  3960 definitions that have local scope;
  3961 
  3962 * new theory section 'nonterminals' for purely syntactic types;
  3963 
  3964 * new theory section 'setup' for generic ML setup functions
  3965 (e.g. package initialization);
  3966 
  3967 * the distribution now includes Isabelle icons: see
  3968 lib/logo/isabelle-{small,tiny}.xpm;
  3969 
  3970 * isatool install - install binaries with absolute references to
  3971 ISABELLE_HOME/bin;
  3972 
  3973 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3974 
  3975 * print mode 'emacs' reserved for Isamode;
  3976 
  3977 * support multiple print (ast) translations per constant name;
  3978 
  3979 * theorems involving oracles are now printed with a suffixed [!];
  3980 
  3981 
  3982 *** HOL ***
  3983 
  3984 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3985 
  3986 * HOL/inductive package reorganized and improved: now supports mutual
  3987 definitions such as
  3988 
  3989   inductive EVEN ODD
  3990     intrs
  3991       null "0 : EVEN"
  3992       oddI "n : EVEN ==> Suc n : ODD"
  3993       evenI "n : ODD ==> Suc n : EVEN"
  3994 
  3995 new theorem list "elims" contains an elimination rule for each of the
  3996 recursive sets; inductive definitions now handle disjunctive premises
  3997 correctly (also ZF);
  3998 
  3999 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4000 "mutual_induct" no longer exists - the induction rule is always
  4001 contained in "induct";
  4002 
  4003 
  4004 * HOL/datatype package re-implemented and greatly improved: now
  4005 supports mutually recursive datatypes such as
  4006 
  4007   datatype
  4008     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4009             | SUM ('a aexp) ('a aexp)
  4010             | DIFF ('a aexp) ('a aexp)
  4011             | NUM 'a
  4012   and
  4013     'a bexp = LESS ('a aexp) ('a aexp)
  4014             | AND ('a bexp) ('a bexp)
  4015             | OR ('a bexp) ('a bexp)
  4016 
  4017 as well as indirectly recursive datatypes such as
  4018 
  4019   datatype
  4020     ('a, 'b) term = Var 'a
  4021                   | App 'b ((('a, 'b) term) list)
  4022 
  4023 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4024 induction on mutually / indirectly recursive datatypes.
  4025 
  4026 Primrec equations are now stored in theory and can be accessed via
  4027 <function_name>.simps.
  4028 
  4029 INCOMPATIBILITIES:
  4030 
  4031   - Theories using datatypes must now have theory Datatype as an
  4032     ancestor.
  4033   - The specific <typename>.induct_tac no longer exists - use the
  4034     generic induct_tac instead.
  4035   - natE has been renamed to nat.exhaust - use exhaust_tac
  4036     instead of res_inst_tac ... natE. Note that the variable
  4037     names in nat.exhaust differ from the names in natE, this
  4038     may cause some "fragile" proofs to fail.
  4039   - The theorems split_<typename>_case and split_<typename>_case_asm
  4040     have been renamed to <typename>.split and <typename>.split_asm.
  4041   - Since default sorts of type variables are now handled correctly,
  4042     some datatype definitions may have to be annotated with explicit
  4043     sort constraints.
  4044   - Primrec definitions no longer require function name and type
  4045     of recursive argument.
  4046 
  4047 Consider using isatool fixdatatype to adapt your theories and proof
  4048 scripts to the new package (backup your sources first!).
  4049 
  4050 
  4051 * HOL/record package: considerably improved implementation; now
  4052 includes concrete syntax for record types, terms, updates; theorems
  4053 for surjective pairing and splitting !!-bound record variables; proof
  4054 support is as follows:
  4055 
  4056   1) standard conversions (selectors or updates applied to record
  4057 constructor terms) are part of the standard simpset;
  4058 
  4059   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4060 made part of standard simpset and claset via addIffs;
  4061 
  4062   3) a tactic for record field splitting (record_split_tac) is part of
  4063 the standard claset (addSWrapper);
  4064 
  4065 To get a better idea about these rules you may retrieve them via
  4066 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4067 the name of your record type.
  4068 
  4069 The split tactic 3) conceptually simplifies by the following rule:
  4070 
  4071   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4072 
  4073 Thus any record variable that is bound by meta-all will automatically
  4074 blow up into some record constructor term, consequently the
  4075 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4076 solve record problems automatically.
  4077 
  4078 
  4079 * reorganized the main HOL image: HOL/Integ and String loaded by
  4080 default; theory Main includes everything;
  4081 
  4082 * automatic simplification of integer sums and comparisons, using cancellation;
  4083 
  4084 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4085 
  4086 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4087 
  4088 * many new identities for unions, intersections, set difference, etc.;
  4089 
  4090 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4091 called split_if, split_split, split_sum_case and split_nat_case (to go
  4092 with add/delsplits);
  4093 
  4094 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4095 (?x::unit) = (); this is made part of the default simpset, which COULD
  4096 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4097 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4098 unit_abs_eta_conv is added in order to counter the effect of
  4099 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4100 %u.f();
  4101 
  4102 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4103 makes more sense);
  4104 
  4105 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4106   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4107   disjointness reasoning but breaking a few old proofs.
  4108 
  4109 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4110 to 'converse' from 'inverse' (for compatibility with ZF and some
  4111 literature);
  4112 
  4113 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4114 the well-founded relation;
  4115 
  4116 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4117     Compl A.  The "Compl" syntax remains available as input syntax for this
  4118     release ONLY.
  4119 
  4120 * HOL/Update: new theory of function updates:
  4121     f(a:=b) == %x. if x=a then b else f x
  4122 may also be iterated as in f(a:=b,c:=d,...);
  4123 
  4124 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4125 
  4126 * HOL/List:
  4127   - new function list_update written xs[i:=v] that updates the i-th
  4128     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4129   - new function `upt' written [i..j(] which generates the list
  4130     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4131     bound write [i..j], which is a shorthand for [i..j+1(].
  4132   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4133 
  4134 * HOL/Arith:
  4135   - removed 'pred' (predecessor) function;
  4136   - generalized some theorems about n-1;
  4137   - many new laws about "div" and "mod";
  4138   - new laws about greatest common divisors (see theory ex/Primes);
  4139 
  4140 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4141 instead of "inverse";
  4142 
  4143 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4144   of the multiset ordering;
  4145 
  4146 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4147   (not included by default);
  4148 
  4149 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4150 
  4151 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4152   programs, i.e. different program variables may have different types.
  4153 
  4154 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4155   [previously, this check worked only if the rewrite rule was unconditional]
  4156   Now rew can involve either definitions or equalities (either == or =).
  4157 
  4158 
  4159 *** ZF ***
  4160 
  4161 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4162   only the theorems proved on ZF.ML;
  4163 
  4164 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4165   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4166   disjointness reasoning but breaking a few old proofs.
  4167 
  4168 * ZF/Update: new theory of function updates
  4169     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4170   may also be iterated as in f(a:=b,c:=d,...);
  4171 
  4172 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4173 
  4174 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4175   [previously, this check worked only if the rewrite rule was unconditional]
  4176   Now rew can involve either definitions or equalities (either == or =).
  4177 
  4178 * case_tac provided for compatibility with HOL
  4179     (like the old excluded_middle_tac, but with subgoals swapped)
  4180 
  4181 
  4182 *** Internal programming interfaces ***
  4183 
  4184 * Pure: several new basic modules made available for general use, see
  4185 also src/Pure/README;
  4186 
  4187 * improved the theory data mechanism to support encapsulation (data
  4188 kind name replaced by private Object.kind, acting as authorization
  4189 key); new type-safe user interface via functor TheoryDataFun; generic
  4190 print_data function becomes basically useless;
  4191 
  4192 * removed global_names compatibility flag -- all theory declarations
  4193 are qualified by default;
  4194 
  4195 * module Pure/Syntax now offers quote / antiquote translation
  4196 functions (useful for Hoare logic etc. with implicit dependencies);
  4197 see HOL/ex/Antiquote for an example use;
  4198 
  4199 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4200 cterm -> thm;
  4201 
  4202 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4203 subgoal;
  4204 
  4205 * Display.print_goals function moved to Locale.print_goals;
  4206 
  4207 * standard print function for goals supports current_goals_markers
  4208 variable for marking begin of proof, end of proof, start of goal; the
  4209 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4210 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4211 for example;
  4212 
  4213 
  4214 
  4215 New in Isabelle98 (January 1998)
  4216 --------------------------------
  4217 
  4218 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4219 
  4220 * changed lexical syntax of terms / types: dots made part of long
  4221 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4222 
  4223 * simpset (and claset) reference variable replaced by functions
  4224 simpset / simpset_ref;
  4225 
  4226 * no longer supports theory aliases (via merge) and non-trivial
  4227 implicit merge of thms' signatures;
  4228 
  4229 * most internal names of constants changed due to qualified names;
  4230 
  4231 * changed Pure/Sequence interface (see Pure/seq.ML);
  4232 
  4233 
  4234 *** General Changes ***
  4235 
  4236 * hierachically structured name spaces (for consts, types, axms, thms
  4237 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4238 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4239 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4240 long_names for fully qualified output names; NOTE: ML programs
  4241 (special tactics, packages etc.) referring to internal names may have
  4242 to be adapted to cope with fully qualified names; in case of severe
  4243 backward campatibility problems try setting 'global_names' at compile
  4244 time to have enrything declared within a flat name space; one may also
  4245 fine tune name declarations in theories via the 'global' and 'local'
  4246 section;
  4247 
  4248 * reimplemented the implicit simpset and claset using the new anytype
  4249 data filed in signatures; references simpset:simpset ref etc. are
  4250 replaced by functions simpset:unit->simpset and
  4251 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4252 to patch your ML files accordingly;
  4253 
  4254 * HTML output now includes theory graph data for display with Java
  4255 applet or isatool browser; data generated automatically via isatool
  4256 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4257 
  4258 * defs may now be conditional; improved rewrite_goals_tac to handle
  4259 conditional equations;
  4260 
  4261 * defs now admits additional type arguments, using TYPE('a) syntax;
  4262 
  4263 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4264 creates a new theory node; implicit merge of thms' signatures is
  4265 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4266 transfer:theory->thm->thm in (rare) cases;
  4267 
  4268 * improved handling of draft signatures / theories; draft thms (and
  4269 ctyps, cterms) are automatically promoted to real ones;
  4270 
  4271 * slightly changed interfaces for oracles: admit many per theory, named
  4272 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4273 
  4274 * print_goals: optional output of const types (set show_consts and
  4275 show_types);
  4276 
  4277 * improved output of warnings (###) and errors (***);
  4278 
  4279 * subgoal_tac displays a warning if the new subgoal has type variables;
  4280 
  4281 * removed old README and Makefiles;
  4282 
  4283 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4284 
  4285 * removed obsolete init_pps and init_database;
  4286 
  4287 * deleted the obsolete tactical STATE, which was declared by
  4288     fun STATE tacfun st = tacfun st st;
  4289 
  4290 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4291 (which abbreviates $HOME);
  4292 
  4293 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4294 use isatool fixseq to adapt your ML programs (this works for fully
  4295 qualified references to the Sequence structure only!);
  4296 
  4297 * use_thy no longer requires writable current directory; it always
  4298 reloads .ML *and* .thy file, if either one is out of date;
  4299 
  4300 
  4301 *** Classical Reasoner ***
  4302 
  4303 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4304 tactics that use classical reasoning to simplify a subgoal without
  4305 splitting it into several subgoals;
  4306 
  4307 * Safe_tac: like safe_tac but uses the default claset;
  4308 
  4309 
  4310 *** Simplifier ***
  4311 
  4312 * added simplification meta rules:
  4313     (asm_)(full_)simplify: simpset -> thm -> thm;
  4314 
  4315 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4316 logics (again);
  4317 
  4318 * added prems argument to simplification procedures;
  4319 
  4320 * HOL, FOL, ZF: added infix function `addsplits':
  4321   instead of `<simpset> setloop (split_tac <thms>)'
  4322   you can simply write `<simpset> addsplits <thms>'
  4323 
  4324 
  4325 *** Syntax ***
  4326 
  4327 * TYPE('a) syntax for type reflection terms;
  4328 
  4329 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4330 
  4331 * pretty printer: changed order of mixfix annotation preference (again!);
  4332 
  4333 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4334 
  4335 
  4336 *** HOL ***
  4337 
  4338 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4339   with `addloop' of the simplifier to faciliate case splitting in premises.
  4340 
  4341 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4342 
  4343 * HOL/Auth: new protocol proofs including some for the Internet
  4344   protocol TLS;
  4345 
  4346 * HOL/Map: new theory of `maps' a la VDM;
  4347 
  4348 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4349 cancelling out common nat summands from =, <, <= (in)equalities, or
  4350 differences; simplification procedures nat_cancel_factor for
  4351 cancelling common factor from =, <, <= (in)equalities over natural
  4352 sums; nat_cancel contains both kinds of procedures, it is installed by
  4353 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4354 
  4355 * HOL/simplifier: terms of the form
  4356   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4357   are rewritten to
  4358   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4359   and those of the form
  4360   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4361   are rewritten to
  4362   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4363 
  4364 * HOL/datatype
  4365   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4366 
  4367   P(t_case f1 ... fn x) =
  4368      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4369         ...
  4370        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4371      )
  4372 
  4373   and a theorem `split_t_case_asm' of the form
  4374 
  4375   P(t_case f1 ... fn x) =
  4376     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4377         ...
  4378        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4379      )
  4380   which can be added to a simpset via `addsplits'. The existing theorems
  4381   expand_list_case and expand_option_case have been renamed to
  4382   split_list_case and split_option_case.
  4383 
  4384 * HOL/Arithmetic:
  4385   - `pred n' is automatically converted to `n-1'.
  4386     Users are strongly encouraged not to use `pred' any longer,
  4387     because it will disappear altogether at some point.
  4388   - Users are strongly encouraged to write "0 < n" rather than
  4389     "n ~= 0". Theorems and proof tools have been modified towards this
  4390     `standard'.
  4391 
  4392 * HOL/Lists:
  4393   the function "set_of_list" has been renamed "set" (and its theorems too);
  4394   the function "nth" now takes its arguments in the reverse order and
  4395   has acquired the infix notation "!" as in "xs!n".
  4396 
  4397 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4398 
  4399 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4400   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4401 
  4402 * HOL/record: extensible records with schematic structural subtyping
  4403 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4404 still lacks various theorems and concrete record syntax;
  4405 
  4406 
  4407 *** HOLCF ***
  4408 
  4409 * removed "axioms" and "generated by" sections;
  4410 
  4411 * replaced "ops" section by extended "consts" section, which is capable of
  4412   handling the continuous function space "->" directly;
  4413 
  4414 * domain package:
  4415   . proves theorems immediately and stores them in the theory,
  4416   . creates hierachical name space,
  4417   . now uses normal mixfix annotations (instead of cinfix...),
  4418   . minor changes to some names and values (for consistency),
  4419   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4420   . separator between mutual domain defs: changed "," to "and",
  4421   . improved handling of sort constraints;  now they have to
  4422     appear on the left-hand side of the equations only;
  4423 
  4424 * fixed LAM <x,y,zs>.b syntax;
  4425 
  4426 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4427 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4428 
  4429 
  4430 *** FOL and ZF ***
  4431 
  4432 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4433   with `addloop' of the simplifier to faciliate case splitting in premises.
  4434 
  4435 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4436 in HOL, they strip ALL and --> from proved theorems;
  4437 
  4438 
  4439 
  4440 New in Isabelle94-8 (May 1997)
  4441 ------------------------------
  4442 
  4443 *** General Changes ***
  4444 
  4445 * new utilities to build / run / maintain Isabelle etc. (in parts
  4446 still somewhat experimental); old Makefiles etc. still functional;
  4447 
  4448 * new 'Isabelle System Manual';
  4449 
  4450 * INSTALL text, together with ./configure and ./build scripts;
  4451 
  4452 * reimplemented type inference for greater efficiency, better error
  4453 messages and clean internal interface;
  4454 
  4455 * prlim command for dealing with lots of subgoals (an easier way of
  4456 setting goals_limit);
  4457 
  4458 
  4459 *** Syntax ***
  4460 
  4461 * supports alternative (named) syntax tables (parser and pretty
  4462 printer); internal interface is provided by add_modesyntax(_i);
  4463 
  4464 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4465 be used in conjunction with the Isabelle symbol font; uses the
  4466 "symbols" syntax table;
  4467 
  4468 * added token_translation interface (may translate name tokens in
  4469 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4470 the current print_mode); IMPORTANT: user print translation functions
  4471 are responsible for marking newly introduced bounds
  4472 (Syntax.mark_boundT);
  4473 
  4474 * token translations for modes "xterm" and "xterm_color" that display
  4475 names in bold, underline etc. or colors (which requires a color
  4476 version of xterm);
  4477 
  4478 * infixes may now be declared with names independent of their syntax;
  4479 
  4480 * added typed_print_translation (like print_translation, but may
  4481 access type of constant);
  4482 
  4483 
  4484 *** Classical Reasoner ***
  4485 
  4486 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4487 some limitations.  Blast_tac...
  4488   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4489   + ignores elimination rules that don't have the correct format
  4490         (the conclusion MUST be a formula variable)
  4491   + ignores types, which can make HOL proofs fail
  4492   + rules must not require higher-order unification, e.g. apply_type in ZF
  4493     [message "Function Var's argument not a bound variable" relates to this]
  4494   + its proof strategy is more general but can actually be slower
  4495 
  4496 * substitution with equality assumptions no longer permutes other
  4497 assumptions;
  4498 
  4499 * minor changes in semantics of addafter (now called addaltern); renamed
  4500 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4501 (and access functions for it);
  4502 
  4503 * improved combination of classical reasoner and simplifier:
  4504   + functions for handling clasimpsets
  4505   + improvement of addss: now the simplifier is called _after_ the
  4506     safe steps.
  4507   + safe variant of addss called addSss: uses safe simplifications
  4508     _during_ the safe steps. It is more complete as it allows multiple
  4509     instantiations of unknowns (e.g. with slow_tac).
  4510 
  4511 *** Simplifier ***
  4512 
  4513 * added interface for simplification procedures (functions that
  4514 produce *proven* rewrite rules on the fly, depending on current
  4515 redex);
  4516 
  4517 * ordering on terms as parameter (used for ordered rewriting);
  4518 
  4519 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4520 
  4521 * the solver is now split into a safe and an unsafe part.
  4522 This should be invisible for the normal user, except that the
  4523 functions setsolver and addsolver have been renamed to setSolver and
  4524 addSolver; added safe_asm_full_simp_tac;
  4525 
  4526 
  4527 *** HOL ***
  4528 
  4529 * a generic induction tactic `induct_tac' which works for all datatypes and
  4530 also for type `nat';
  4531 
  4532 * a generic case distinction tactic `exhaust_tac' which works for all
  4533 datatypes and also for type `nat';
  4534 
  4535 * each datatype comes with a function `size';
  4536 
  4537 * patterns in case expressions allow tuple patterns as arguments to
  4538 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4539 
  4540 * primrec now also works with type nat;
  4541 
  4542 * recdef: a new declaration form, allows general recursive functions to be
  4543 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4544 
  4545 * the constant for negation has been renamed from "not" to "Not" to
  4546 harmonize with FOL, ZF, LK, etc.;
  4547 
  4548 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4549 infinite lists;
  4550 
  4551 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4552 
  4553 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4554 problems in commutative rings, using axiomatic type classes for + and *;
  4555 
  4556 * more examples in HOL/MiniML and HOL/Auth;
  4557 
  4558 * more default rewrite rules for quantifiers, union/intersection;
  4559 
  4560 * a new constant `arbitrary == @x.False';
  4561 
  4562 * HOLCF/IOA replaces old HOL/IOA;
  4563 
  4564 * HOLCF changes: derived all rules and arities
  4565   + axiomatic type classes instead of classes
  4566   + typedef instead of faking type definitions
  4567   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4568   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4569   + eliminated the types void, one, tr
  4570   + use unit lift and bool lift (with translations) instead of one and tr
  4571   + eliminated blift from Lift3.thy (use Def instead of blift)
  4572   all eliminated rules are derived as theorems --> no visible changes ;
  4573 
  4574 
  4575 *** ZF ***
  4576 
  4577 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4578 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4579 as ZF_cs addSIs [equalityI];
  4580 
  4581 
  4582 
  4583 New in Isabelle94-7 (November 96)
  4584 ---------------------------------
  4585 
  4586 * allowing negative levels (as offsets) in prlev and choplev;
  4587 
  4588 * super-linear speedup for large simplifications;
  4589 
  4590 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4591 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4592 FAIL); can suppress it using the command Delsimps (ex_simps @
  4593 all_simps); De Morgan laws are also now included, by default;
  4594 
  4595 * improved printing of ==>  :  ~:
  4596 
  4597 * new object-logic "Sequents" adds linear logic, while replacing LK
  4598 and Modal (thanks to Sara Kalvala);
  4599 
  4600 * HOL/Auth: correctness proofs for authentication protocols;
  4601 
  4602 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4603 examples on HOL/Auth);
  4604 
  4605 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4606 the rewriter and classical reasoner simultaneously;
  4607 
  4608 * function uresult no longer returns theorems in "standard" format;
  4609 regain previous version by: val uresult = standard o uresult;
  4610 
  4611 
  4612 
  4613 New in Isabelle94-6
  4614 -------------------
  4615 
  4616 * oracles -- these establish an interface between Isabelle and trusted
  4617 external reasoners, which may deliver results as theorems;
  4618 
  4619 * proof objects (in particular record all uses of oracles);
  4620 
  4621 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4622 
  4623 * "constdefs" section in theory files;
  4624 
  4625 * "primrec" section (HOL) no longer requires names;
  4626 
  4627 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4628 
  4629 
  4630 
  4631 New in Isabelle94-5
  4632 -------------------
  4633 
  4634 * reduced space requirements;
  4635 
  4636 * automatic HTML generation from theories;
  4637 
  4638 * theory files no longer require "..." (quotes) around most types;
  4639 
  4640 * new examples, including two proofs of the Church-Rosser theorem;
  4641 
  4642 * non-curried (1994) version of HOL is no longer distributed;
  4643 
  4644 
  4645 
  4646 New in Isabelle94-4
  4647 -------------------
  4648 
  4649 * greatly reduced space requirements;
  4650 
  4651 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4652 
  4653 * searchable theorem database (see the section "Retrieving theorems" on
  4654 page 8 of the Reference Manual);
  4655 
  4656 * new examples, including Grabczewski's monumental case study of the
  4657 Axiom of Choice;
  4658 
  4659 * The previous version of HOL renamed to Old_HOL;
  4660 
  4661 * The new version of HOL (previously called CHOL) uses a curried syntax
  4662 for functions.  Application looks like f a b instead of f(a,b);
  4663 
  4664 * Mutually recursive inductive definitions finally work in HOL;
  4665 
  4666 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4667 translates to the operator "split";
  4668 
  4669 
  4670 
  4671 New in Isabelle94-3
  4672 -------------------
  4673 
  4674 * new infix operator, addss, allowing the classical reasoner to
  4675 perform simplification at each step of its search.  Example:
  4676         fast_tac (cs addss ss)
  4677 
  4678 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4679 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4680 look like (a,b) instead of <a,b>;
  4681 
  4682 * PLEASE NOTE: CHOL will eventually replace HOL!
  4683 
  4684 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4685 It translates to the operator "split".  A new theory of integers is available;
  4686 
  4687 * In ZF, integer numerals now denote two's-complement binary integers.
  4688 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4689 
  4690 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4691 of the Axiom of Choice;
  4692 
  4693 
  4694 
  4695 New in Isabelle94-2
  4696 -------------------
  4697 
  4698 * Significantly faster resolution;
  4699 
  4700 * the different sections in a .thy file can now be mixed and repeated
  4701 freely;
  4702 
  4703 * Database of theorems for FOL, HOL and ZF.  New
  4704 commands including qed, qed_goal and bind_thm store theorems in the database.
  4705 
  4706 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4707 a given theory (thms_of), or find out what theory a theorem was proved in
  4708 (theory_of_thm);
  4709 
  4710 * Bugs fixed in the inductive definition and datatype packages;
  4711 
  4712 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4713 and HOL_dup_cs obsolete;
  4714 
  4715 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4716 have been removed;
  4717 
  4718 * Simpler definition of function space in ZF;
  4719 
  4720 * new results about cardinal and ordinal arithmetic in ZF;
  4721 
  4722 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4723 types;
  4724 
  4725 
  4726 $Id$