NEWS
author obua
Mon Jun 25 14:49:32 2007 +0200 (2007-06-25)
changeset 23495 e4dd6beeafab
parent 23481 93dca7620d0d
child 23509 14a2f87ccc73
permissions -rw-r--r--
commented changes in HOL/Ring_and_Field.thy, and in HOL/Real/RealPow.thy
     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). FUTURE INCOMPATIBILITY:
    12 legacy features will disappear eventually.
    13 
    14 * Theory syntax: the header format ``theory A = B + C:'' has been
    15 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    16 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    17 
    18 * Theory syntax: the old non-Isar theory file format has been
    19 discontinued altogether.  Note that ML proof scripts may still be used
    20 with Isar theories; migration is usually quite simple with the ML
    21 function use_legacy_bindings.  INCOMPATIBILITY.
    22 
    23 * Theory syntax: some popular names (e.g. 'class', 'declaration',
    24 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
    25 quotes.
    26 
    27 * Legacy goal package: reduced interface to the bare minimum required
    28 to keep existing proof scripts running.  Most other user-level
    29 functions are now part of the OldGoals structure, which is *not* open
    30 by default (consider isatool expandshort before open OldGoals).
    31 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    32 these tend to cause confusion about the actual goal (!) context being
    33 used here, which is not necessarily the same as the_context().
    34 
    35 * Command 'find_theorems': supports "*" wild-card in "name:"
    36 criterion; "with_dups" option.  Certain ProofGeneral versions might
    37 support a specific search form (see ProofGeneral/CHANGES).
    38 
    39 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    40 by default, which means that "prems" (and also "fixed variables") are
    41 suppressed from proof state output.  Note that the ProofGeneral
    42 settings mechanism allows to change and save options persistently, but
    43 older versions of Isabelle will fail to start up if a negative prems
    44 limit is imposed.
    45 
    46 * Local theory targets may be specified by non-nested blocks of
    47 ``context/locale/class ... begin'' followed by ``end''.  The body may
    48 contain definitions, theorems etc., including any derived mechanism
    49 that has been implemented on top of these primitives.  This concept
    50 generalizes the existing ``theorem (in ...)'' towards more versatility
    51 and scalability.
    52 
    53 * Proof General interface: proper undo of final 'end' command;
    54 discontinued Isabelle/classic mode (ML proof scripts).
    55 
    56 
    57 *** Document preparation ***
    58 
    59 * Added antiquotation @{theory name} which prints the given name,
    60 after checking that it refers to a valid ancestor theory in the
    61 current context.
    62 
    63 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    64 check the given source text as ML type/structure, printing verbatim.
    65 
    66 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    67 "c args == rhs" given in the current context.  (Any number of
    68 arguments may be given on the LHS.)
    69 
    70 
    71 
    72 *** Pure ***
    73 
    74 * code generator: consts in 'consts_code' Isar commands are now referred
    75   to by usual term syntax (including optional type annotations).
    76 
    77 * code generator: 
    78   - Isar 'definition's, 'constdef's and primitive instance definitions are added
    79     explicitly to the table of defining equations
    80   - primitive definitions are not used as defining equations by default any longer
    81   - defining equations are now definitly restricted to meta "==" and object
    82         equality "="
    83   - HOL theories have been adopted accordingly
    84 
    85 * class_package.ML offers a combination of axclasses and locales to
    86 achieve Haskell-like type classes in Isabelle.  See
    87 HOL/ex/Classpackage.thy for examples.
    88 
    89 * Yet another code generator framework allows to generate executable
    90 code for ML and Haskell (including "class"es).  A short usage sketch:
    91 
    92     internal compilation:
    93         code_gen <list of constants (term syntax)> (SML #)
    94     writing SML code to a file:
    95         code_gen <list of constants (term syntax)> (SML <filename>)
    96     writing OCaml code to a file:
    97         code_gen <list of constants (term syntax)> (OCaml <filename>)
    98     writing Haskell code to a bunch of files:
    99         code_gen <list of constants (term syntax)> (Haskell <filename>)
   100 
   101 Reasonable default setup of framework in HOL/Main.
   102 
   103 Theorem attributs for selecting and transforming function equations theorems:
   104 
   105     [code fun]:        select a theorem as function equation for a specific constant
   106     [code fun del]:    deselect a theorem as function equation for a specific constant
   107     [code inline]:     select an equation theorem for unfolding (inlining) in place
   108     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   109 
   110 User-defined serializations (target in {SML, OCaml, Haskell}):
   111 
   112     code_const <and-list of constants (term syntax)>
   113       {(target) <and-list of const target syntax>}+
   114 
   115     code_type <and-list of type constructors>
   116       {(target) <and-list of type target syntax>}+
   117 
   118     code_instance <and-list of instances>
   119       {(target)}+
   120         where instance ::= <type constructor> :: <class>
   121 
   122     code_class <and_list of classes>
   123       {(target) <and-list of class target syntax>}+
   124         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   125 
   126 code_instance and code_class only apply to target Haskell.
   127 
   128 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   129 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   130 
   131 * Command 'no_translations' removes translation rules from theory
   132 syntax.
   133 
   134 * Overloaded definitions are now actually checked for acyclic
   135 dependencies.  The overloading scheme is slightly more general than
   136 that of Haskell98, although Isabelle does not demand an exact
   137 correspondence to type class and instance declarations.
   138 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   139 exotic versions of overloading -- at the discretion of the user!
   140 
   141 Polymorphic constants are represented via type arguments, i.e. the
   142 instantiation that matches an instance against the most general
   143 declaration given in the signature.  For example, with the declaration
   144 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   145 as c(nat).  Overloading is essentially simultaneous structural
   146 recursion over such type arguments.  Incomplete specification patterns
   147 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   148 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   149 Command 'print_theory' outputs the normalized system of recursive
   150 equations, see section "definitions".
   151 
   152 * Isar: method "assumption" (and implicit closing of subproofs) now
   153 takes simple non-atomic goal assumptions into account: after applying
   154 an assumption as a rule the resulting subgoals are solved by atomic
   155 assumption steps.  This is particularly useful to finish 'obtain'
   156 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   157 without referring to the original premise "!!x. P x ==> thesis" in the
   158 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   159 more permissive.
   160 
   161 * Isar: implicit use of prems from the Isar proof context is
   162 considered a legacy feature.  Common applications like ``have A .''
   163 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   164 referencing facts explicitly here improves readability and
   165 maintainability of proof texts.
   166 
   167 * Isar: improper proof element 'guess' is like 'obtain', but derives
   168 the obtained context from the course of reasoning!  For example:
   169 
   170   assume "EX x y. A x & B y"   -- "any previous fact"
   171   then guess x and y by clarify
   172 
   173 This technique is potentially adventurous, depending on the facts and
   174 proof tools being involved here.
   175 
   176 * Isar: known facts from the proof context may be specified as literal
   177 propositions, using ASCII back-quote syntax.  This works wherever
   178 named facts used to be allowed so far, in proof commands, proof
   179 methods, attributes etc.  Literal facts are retrieved from the context
   180 according to unification of type and term parameters.  For example,
   181 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   182 theorems in the current context, then these are valid literal facts:
   183 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   184 
   185 There is also a proof method "fact" which does the same composition
   186 for explicit goal states, e.g. the following proof texts coincide with
   187 certain special cases of literal facts:
   188 
   189   have "A" by fact                 ==  note `A`
   190   have "A ==> B" by fact           ==  note `A ==> B`
   191   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   192   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   193 
   194 * Isar: ":" (colon) is no longer a symbolic identifier character in
   195 outer syntax.  Thus symbolic identifiers may be used without
   196 additional white space in declarations like this: ``assume *: A''.
   197 
   198 * Isar: 'print_facts' prints all local facts of the current context,
   199 both named and unnamed ones.
   200 
   201 * Isar: 'def' now admits simultaneous definitions, e.g.:
   202 
   203   def x == "t" and y == "u"
   204 
   205 * Isar: added command 'unfolding', which is structurally similar to
   206 'using', but affects both the goal state and facts by unfolding given
   207 rewrite rules.  Thus many occurrences of the 'unfold' method or
   208 'unfolded' attribute may be replaced by first-class proof text.
   209 
   210 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   211 and command 'unfolding' now all support object-level equalities
   212 (potentially conditional).  The underlying notion of rewrite rule is
   213 analogous to the 'rule_format' attribute, but *not* that of the
   214 Simplifier (which is usually more generous).
   215 
   216 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   217 method expression within a sandbox consisting of the first N
   218 sub-goals, which need to exist.  For example, ``simp_all [3]''
   219 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   220 simplifies all new goals that emerge from applying rule foo to the
   221 originally first one.
   222 
   223 * Isar: schematic goals are no longer restricted to higher-order
   224 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   225 expected.
   226 
   227 * Isar: the conclusion of a long theorem statement is now either
   228 'shows' (a simultaneous conjunction, as before), or 'obtains'
   229 (essentially a disjunction of cases with local parameters and
   230 assumptions).  The latter allows to express general elimination rules
   231 adequately; in this notation common elimination rules look like this:
   232 
   233   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   234     assumes "EX x. P x"
   235     obtains x where "P x"
   236 
   237   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   238     assumes "A & B"
   239     obtains A and B
   240 
   241   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   242     assumes "A | B"
   243     obtains
   244       A
   245     | B
   246 
   247 The subsequent classical rules even refer to the formal "thesis"
   248 explicitly:
   249 
   250   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   251     obtains "~ thesis"
   252 
   253   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   254     obtains "thesis ==> something"
   255 
   256 The actual proof of an 'obtains' statement is analogous to that of the
   257 Isar proof element 'obtain', only that there may be several cases.
   258 Optional case names may be specified in parentheses; these will be
   259 available both in the present proof and as annotations in the
   260 resulting rule, for later use with the 'cases' method (cf. attribute
   261 case_names).
   262 
   263 * Isar: the assumptions of a long theorem statement are available as
   264 "assms" fact in the proof context.  This is more appropriate than the
   265 (historical) "prems", which refers to all assumptions of the current
   266 context, including those from the target locale, proof body etc.
   267 
   268 * Isar: 'print_statement' prints theorems from the current theory or
   269 proof context in long statement form, according to the syntax of a
   270 top-level lemma.
   271 
   272 * Isar: 'obtain' takes an optional case name for the local context
   273 introduction rule (default "that").
   274 
   275 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   276 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   277 to occur.
   278 
   279 * Pure: syntax "CONST name" produces a fully internalized constant
   280 according to the current context.  This is particularly useful for
   281 syntax translations that should refer to internal constant
   282 representations independently of name spaces.
   283 
   284 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   285 instead of "FOO ". This allows multiple binder declarations to coexist
   286 in the same context.  INCOMPATIBILITY.
   287 
   288 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   289 primitive that also works in a locale context (both for constants and
   290 fixed variables).  Type declaration and internal syntactic
   291 representation of given constants retrieved from the context.
   292 
   293 * Isar/locales: new derived specification elements 'axiomatization',
   294 'definition', 'abbreviation', which support type-inference, admit
   295 object-level specifications (equality, equivalence).  See also the
   296 isar-ref manual.  Examples:
   297 
   298   axiomatization
   299     eq  (infix "===" 50) where
   300     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   301 
   302   definition "f x y = x + y + 1"
   303   definition g where "g x = f x x"
   304 
   305   abbreviation
   306     neq  (infix "=!=" 50) where
   307     "x =!= y == ~ (x === y)"
   308 
   309 These specifications may be also used in a locale context.  Then the
   310 constants being introduced depend on certain fixed parameters, and the
   311 constant name is qualified by the locale base name.  An internal
   312 abbreviation takes care for convenient input and output, making the
   313 parameters implicit and using the original short name.  See also
   314 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   315 entities from a monomorphic theory.
   316 
   317 Presently, abbreviations are only available 'in' a target locale, but
   318 not inherited by general import expressions.  Also note that
   319 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   320 'translations' in common applications.
   321 
   322 Concrete syntax is attached to specified constants in internal form,
   323 independently of name spaces.  The parse tree representation is
   324 slightly different -- use 'notation' instead of raw 'syntax', and
   325 'translations' with explicit "CONST" markup to accommodate this.
   326 
   327 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   328 the current context.  Print mode "no_abbrevs" prevents inversion of
   329 abbreviations on output.
   330 
   331 * Isar/locales: improved parameter handling:
   332 - use of locales "var" and "struct" no longer necessary;
   333 - parameter renamings are no longer required to be injective.
   334   This enables, for example, to define a locale for endomorphisms thus:
   335   locale endom = homom mult mult h.
   336 
   337 * Isar/locales: changed the way locales with predicates are defined.
   338 Instead of accumulating the specification, the imported expression is
   339 now an interpretation.  INCOMPATIBILITY: different normal form of
   340 locale expressions.  In particular, in interpretations of locales with
   341 predicates, goals repesenting already interpreted fragments are not
   342 removed automatically.  Use methods `intro_locales' and
   343 `unfold_locales'; see below.
   344 
   345 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   346 provide backward reasoning on locales predicates.  The methods are
   347 aware of interpretations and discharge corresponding goals.
   348 `intro_locales' is less aggressive then `unfold_locales' and does not
   349 unfold predicates to assumptions.
   350 
   351 * Isar/locales: the order in which locale fragments are accumulated
   352 has changed.  This enables to override declarations from fragments due
   353 to interpretations -- for example, unwanted simp rules.
   354 
   355 * Provers/induct: improved internal context management to support
   356 local fixes and defines on-the-fly.  Thus explicit meta-level
   357 connectives !! and ==> are rarely required anymore in inductive goals
   358 (using object-logic connectives for this purpose has been long
   359 obsolete anyway).  The subsequent proof patterns illustrate advanced
   360 techniques of natural induction; general datatypes and inductive sets
   361 work analogously (see also src/HOL/Lambda for realistic examples).
   362 
   363 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   364 parameters:
   365 
   366   lemma
   367     fixes n :: nat and x :: 'a
   368     assumes a: "A n x"
   369     shows "P n x"
   370     using a                     -- {* make induct insert fact a *}
   371   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   372     case 0
   373     show ?case sorry
   374   next
   375     case (Suc n)
   376     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   377     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   378     show ?case sorry
   379   qed
   380 
   381 (2) This is how to perform induction over ``expressions of a certain
   382 form'', using a locally defined inductive parameter n == "a x"
   383 together with strengthening (the latter is usually required to get
   384 sufficiently flexible induction hypotheses):
   385 
   386   lemma
   387     fixes a :: "'a => nat"
   388     assumes a: "A (a x)"
   389     shows "P (a x)"
   390     using a
   391   proof (induct n == "a x" arbitrary: x)
   392     ...
   393 
   394 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   395 particular technique.
   396 
   397 (3) This is how to perform existential reasoning ('obtains' or
   398 'obtain') by induction, while avoiding explicit object-logic
   399 encodings:
   400 
   401   lemma
   402     fixes n :: nat
   403     obtains x :: 'a where "P n x" and "Q n x"
   404   proof (induct n arbitrary: thesis)
   405     case 0
   406     obtain x where "P 0 x" and "Q 0 x" sorry
   407     then show thesis by (rule 0)
   408   next
   409     case (Suc n)
   410     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   411     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   412     then show thesis by (rule Suc.prems)
   413   qed
   414 
   415 Here the 'arbitrary: thesis' specification essentially modifies the
   416 scope of the formal thesis parameter, in order to the get the whole
   417 existence statement through the induction as expected.
   418 
   419 * Provers/induct: mutual induction rules are now specified as a list
   420 of rule sharing the same induction cases.  HOL packages usually
   421 provide foo_bar.inducts for mutually defined items foo and bar
   422 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   423 specify mutual induction rules differently, i.e. like this:
   424 
   425   (induct rule: foo_bar.inducts)
   426   (induct set: foo bar)
   427   (induct type: foo bar)
   428 
   429 The ML function ProjectRule.projections turns old-style rules into the
   430 new format.
   431 
   432 * Provers/induct: improved handling of simultaneous goals.  Instead of
   433 introducing object-level conjunction, the statement is now split into
   434 several conclusions, while the corresponding symbolic cases are
   435 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   436 explicitly.  For example:
   437 
   438   lemma
   439     fixes n :: nat
   440     shows "P n" and "Q n"
   441   proof (induct n)
   442     case 0 case 1
   443     show "P 0" sorry
   444   next
   445     case 0 case 2
   446     show "Q 0" sorry
   447   next
   448     case (Suc n) case 1
   449     note `P n` and `Q n`
   450     show "P (Suc n)" sorry
   451   next
   452     case (Suc n) case 2
   453     note `P n` and `Q n`
   454     show "Q (Suc n)" sorry
   455   qed
   456 
   457 The split into subcases may be deferred as follows -- this is
   458 particularly relevant for goal statements with local premises.
   459 
   460   lemma
   461     fixes n :: nat
   462     shows "A n ==> P n" and "B n ==> Q n"
   463   proof (induct n)
   464     case 0
   465     {
   466       case 1
   467       note `A 0`
   468       show "P 0" sorry
   469     next
   470       case 2
   471       note `B 0`
   472       show "Q 0" sorry
   473     }
   474   next
   475     case (Suc n)
   476     note `A n ==> P n` and `B n ==> Q n`
   477     {
   478       case 1
   479       note `A (Suc n)`
   480       show "P (Suc n)" sorry
   481     next
   482       case 2
   483       note `B (Suc n)`
   484       show "Q (Suc n)" sorry
   485     }
   486   qed
   487 
   488 If simultaneous goals are to be used with mutual rules, the statement
   489 needs to be structured carefully as a two-level conjunction, using
   490 lists of propositions separated by 'and':
   491 
   492   lemma
   493     shows "a : A ==> P1 a"
   494           "a : A ==> P2 a"
   495       and "b : B ==> Q1 b"
   496           "b : B ==> Q2 b"
   497           "b : B ==> Q3 b"
   498   proof (induct set: A B)
   499 
   500 * Provers/induct: support coinduction as well.  See
   501 src/HOL/Library/Coinductive_List.thy for various examples.
   502 
   503 * Attribute "symmetric" produces result with standardized schematic
   504 variables (index 0).  Potential INCOMPATIBILITY.
   505 
   506 * Simplifier: by default the simplifier trace only shows top level
   507 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   508 default. Thus there is less danger of being flooded by the trace. The
   509 trace indicates where parts have been suppressed.
   510   
   511 * Provers/classical: removed obsolete classical version of elim_format
   512 attribute; classical elim/dest rules are now treated uniformly when
   513 manipulating the claset.
   514 
   515 * Provers/classical: stricter checks to ensure that supplied intro,
   516 dest and elim rules are well-formed; dest and elim rules must have at
   517 least one premise.
   518 
   519 * Provers/classical: attributes dest/elim/intro take an optional
   520 weight argument for the rule (just as the Pure versions).  Weights are
   521 ignored by automated tools, but determine the search order of single
   522 rule steps.
   523 
   524 * Syntax: input syntax now supports dummy variable binding "%_. b",
   525 where the body does not mention the bound variable.  Note that dummy
   526 patterns implicitly depend on their context of bounds, which makes
   527 "{_. _}" match any set comprehension as expected.  Potential
   528 INCOMPATIBILITY -- parse translations need to cope with syntactic
   529 constant "_idtdummy" in the binding position.
   530 
   531 * Syntax: removed obsolete syntactic constant "_K" and its associated
   532 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   533 for example "A -> B" => "Pi A (%_. B)".
   534 
   535 * Pure: 'class_deps' command visualizes the subclass relation, using
   536 the graph browser tool.
   537 
   538 * Pure: 'print_theory' now suppresses entities with internal name
   539 (trailing "_") by default; use '!' option for full details.
   540 
   541 
   542 *** HOL ***
   543 
   544 * Method "metis" proves goals by applying the Metis general-purpose resolution prover.
   545   Examples are in the directory MetisExamples.
   546   
   547 * Command "sledgehammer" invokes external automatic theorem provers as background processes.
   548   It generates calls to the "metis" method if successful. These can be pasted into the proof.
   549   Users do not have to wait for the automatic provers to return.
   550 
   551 * IntDef: The constant "int :: nat => int" has been removed; now "int"
   552   is an abbreviation for "of_nat :: nat => int". The simplification rules
   553   for "of_nat" have been changed to work like "int" did previously.
   554   (potential INCOMPATIBILITY)
   555   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
   556   - of_nat_diff and of_nat_mult are no longer default simp rules
   557 
   558 * Method "algebra" solves polynomial equations over (semi)rings using
   559   Groebner bases. The (semi)ring structure is defined by locales and
   560   the tool setup depends on that generic context. Installing the
   561   method for a specific type involves instantiating the locale and
   562   possibly adding declarations for computation on the coefficients.
   563   The method is already instantiated for natural numbers and for the
   564   axiomatic class of idoms with numerals.  See also the paper by
   565   Chaieb and Wenzel at CALCULEMUS 2007 for the general principles
   566   underlying this architecture of context-aware proof-tools.
   567 
   568 * constant "List.op @" now named "List.append".  Use ML antiquotations
   569 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   570 possible incompatibilities when working on ML level.
   571 
   572 * Constant renames due to introduction of canonical name prefixing for
   573   class package:
   574 
   575     HOL.abs ~> HOL.minus_class.abs
   576     HOL.divide ~> HOL.divide_class.divide
   577     Nat.power ~> Nat.power_class.power
   578     Nat.size ~> Nat.size_class.size
   579     Numeral.number_of ~> Numeral.number_class.number_of
   580     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   581 
   582 * Rudimentary class target mechanism involves constant renames:
   583 
   584     Orderings.min ~> Orderings.ord_class.min
   585     Orderings.max ~> Orderings.ord_class.max
   586     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   587 
   588 * case expressions and primrec: missing cases now mapped to "undefined"
   589 instead of "arbitrary"
   590 
   591 * new constant "undefined" with axiom "undefined x = undefined"
   592 
   593 * new class "default" with associated constant "default"
   594 
   595 * new function listsum :: 'a list => 'a for arbitrary monoids.
   596   Special syntax: "SUM x <- xs. f x" (and latex variants)
   597 
   598 * new (input only) syntax for Haskell-like list comprehension, eg
   599   [(x,y). x <- xs, y <- ys, x ~= y]
   600   For details see List.thy.
   601 
   602 * The special syntax for function "filter" has changed from [x : xs. P] to
   603   [x <- xs. P] to avoid an ambiguity caused by list comprehension syntax,
   604   and for uniformity. INCOMPATIBILITY
   605 
   606 * New lemma collection field_simps (an extension of ring_simps)
   607   for manipulating (in)equations involving division. Multiplies
   608   with all denominators that can be proved to be non-zero (in equations)
   609   or positive/negative (in inequations).
   610 
   611 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
   612   have been improved and renamed to ring_simps, group_simps and ring_distribs.
   613 
   614 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   615   when generating code.
   616 
   617 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   618   when generating code.
   619 
   620 * Library/Commutative_Ring.thy: switched from recdef to function package;
   621   constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   622 
   623 * Some steps towards more uniform lattice theory development in HOL.
   624 
   625     constants "meet" and "join" now named "inf" and "sup"
   626     constant "Meet" now named "Inf"
   627 
   628     classes "meet_semilorder" and "join_semilorder" now named
   629       "lower_semilattice" and "upper_semilattice"
   630     class "lorder" now named "lattice"
   631     class "comp_lat" now named "complete_lattice"
   632 
   633     Instantiation of lattice classes allows explicit definitions
   634     for "inf" and "sup" operations.
   635 
   636   INCOMPATIBILITY.  Theorem renames:
   637 
   638     meet_left_le            ~> inf_le1
   639     meet_right_le           ~> inf_le2
   640     join_left_le            ~> sup_ge1
   641     join_right_le           ~> sup_ge2
   642     meet_join_le            ~> inf_sup_ord
   643     le_meetI                ~> le_infI
   644     join_leI                ~> le_supI
   645     le_meet                 ~> le_inf_iff
   646     le_join                 ~> ge_sup_conv
   647     meet_idempotent         ~> inf_idem
   648     join_idempotent         ~> sup_idem
   649     meet_comm               ~> inf_commute
   650     join_comm               ~> sup_commute
   651     meet_leI1               ~> le_infI1
   652     meet_leI2               ~> le_infI2
   653     le_joinI1               ~> le_supI1
   654     le_joinI2               ~> le_supI2
   655     meet_assoc              ~> inf_assoc
   656     join_assoc              ~> sup_assoc
   657     meet_left_comm          ~> inf_left_commute
   658     meet_left_idempotent    ~> inf_left_idem
   659     join_left_comm          ~> sup_left_commute
   660     join_left_idempotent    ~> sup_left_idem
   661     meet_aci                ~> inf_aci
   662     join_aci                ~> sup_aci
   663     le_def_meet             ~> le_iff_inf
   664     le_def_join             ~> le_iff_sup
   665     join_absorp2            ~> sup_absorb2
   666     join_absorp1            ~> sup_absorb1
   667     meet_absorp1            ~> inf_absorb1
   668     meet_absorp2            ~> inf_absorb2
   669     meet_join_absorp        ~> inf_sup_absorb
   670     join_meet_absorp        ~> sup_inf_absorb
   671     distrib_join_le         ~> distrib_sup_le
   672     distrib_meet_le         ~> distrib_inf_le
   673 
   674     add_meet_distrib_left   ~> add_inf_distrib_left
   675     add_join_distrib_left   ~> add_sup_distrib_left
   676     is_join_neg_meet        ~> is_join_neg_inf
   677     is_meet_neg_join        ~> is_meet_neg_sup
   678     add_meet_distrib_right  ~> add_inf_distrib_right
   679     add_join_distrib_right  ~> add_sup_distrib_right
   680     add_meet_join_distribs  ~> add_sup_inf_distribs
   681     join_eq_neg_meet        ~> sup_eq_neg_inf
   682     meet_eq_neg_join        ~> inf_eq_neg_sup
   683     add_eq_meet_join        ~> add_eq_inf_sup
   684     meet_0_imp_0            ~> inf_0_imp_0
   685     join_0_imp_0            ~> sup_0_imp_0
   686     meet_0_eq_0             ~> inf_0_eq_0
   687     join_0_eq_0             ~> sup_0_eq_0
   688     neg_meet_eq_join        ~> neg_inf_eq_sup
   689     neg_join_eq_meet        ~> neg_sup_eq_inf
   690     join_eq_if              ~> sup_eq_if
   691 
   692     mono_meet               ~> mono_inf
   693     mono_join               ~> mono_sup
   694     meet_bool_eq            ~> inf_bool_eq
   695     join_bool_eq            ~> sup_bool_eq
   696     meet_fun_eq             ~> inf_fun_eq
   697     join_fun_eq             ~> sup_fun_eq
   698     meet_set_eq             ~> inf_set_eq
   699     join_set_eq             ~> sup_set_eq
   700     meet1_iff               ~> inf1_iff
   701     meet2_iff               ~> inf2_iff
   702     meet1I                  ~> inf1I
   703     meet2I                  ~> inf2I
   704     meet1D1                 ~> inf1D1
   705     meet2D1                 ~> inf2D1
   706     meet1D2                 ~> inf1D2
   707     meet2D2                 ~> inf2D2
   708     meet1E                  ~> inf1E
   709     meet2E                  ~> inf2E
   710     join1_iff               ~> sup1_iff
   711     join2_iff               ~> sup2_iff
   712     join1I1                 ~> sup1I1
   713     join2I1                 ~> sup2I1
   714     join1I1                 ~> sup1I1
   715     join2I2                 ~> sup1I2
   716     join1CI                 ~> sup1CI
   717     join2CI                 ~> sup2CI
   718     join1E                  ~> sup1E
   719     join2E                  ~> sup2E
   720 
   721     is_meet_Meet            ~> is_meet_Inf
   722     Meet_bool_def           ~> Inf_bool_def
   723     Meet_fun_def            ~> Inf_fun_def
   724     Meet_greatest           ~> Inf_greatest
   725     Meet_lower              ~> Inf_lower
   726     Meet_set_def            ~> Inf_set_def
   727 
   728     listsp_meetI            ~> listsp_infI
   729     listsp_meet_eq          ~> listsp_inf_eq
   730 
   731     meet_min                ~> inf_min
   732     join_max                ~> sup_max
   733 
   734 * Classes "order" and "linorder": facts "refl", "trans" and
   735 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   736 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   737 
   738 * Classes "order" and "linorder": 
   739 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   740 proofs changed.
   741 
   742 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   743 INCOMPATIBILITY.
   744 
   745 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   746 INCOMPATIBILITY.
   747 
   748 * Added syntactic class "size"; overloaded constant "size" now has
   749 type "'a::size ==> bool"
   750 
   751 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   752 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   753 
   754 * Added method "lexicographic_order" automatically synthesizes
   755 termination relations as lexicographic combinations of size measures
   756 -- 'function' package.
   757 
   758 * HOL/records: generalised field-update to take a function on the
   759 field rather than the new value: r(|A := x|) is translated to A_update
   760 (K x) r The K-combinator that is internally used is called K_record.
   761 INCOMPATIBILITY: Usage of the plain update functions has to be
   762 adapted.
   763  
   764 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   765 0 * x = 0, which are required for a semiring.  Richer structures do
   766 not inherit from semiring_0 anymore, because this property is a
   767 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   768 semiring_0, there is more to prove, but this is mostly trivial.
   769 
   770 * axclass "recpower" was generalized to arbitrary monoids, not just
   771 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   772 commutativity or a semiring property, add the corresponding classes.
   773 
   774 * Unified locale partial_order with class definition (cf. theory
   775 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   776 
   777 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   778 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   779 Isar level, use abbreviations instead.
   780 
   781 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   782 rarely occuring name references (e.g. ``List.op mem.simps'') require
   783 renaming (e.g. ``List.memberl.simps'').
   784 
   785 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   786 INCOMPATIBILITY.
   787 
   788 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
   789 
   790 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   791 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   792 significant changes for setting up numeral syntax for types:
   793 
   794   - new constants Numeral.pred and Numeral.succ instead
   795       of former Numeral.bin_pred and Numeral.bin_succ.
   796   - Use integer operations instead of bin_add, bin_mult and so on.
   797   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   798   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   799 
   800 See HOL/Integ/IntArith.thy for an example setup.
   801 
   802 * New top level command 'normal_form' computes the normal form of a
   803 term that may contain free variables. For example ``normal_form
   804 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   805 suitable for heavy-duty computations because the functions are
   806 compiled to ML first.
   807 
   808 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   809 25 like -->); output depends on the "iff" print_mode, the default is
   810 "A = B" (with priority 50).
   811 
   812 * Renamed constants in HOL.thy and Orderings.thy:
   813     op +   ~> HOL.plus_class.plus
   814     op -   ~> HOL.minus_class.minus
   815     uminus ~> HOL.minus_class.uminus
   816     op *   ~> HOL.times_class.times
   817     op <   ~> Orderings.ord_class.less
   818     op <=  ~> Orderings.ord_class.less_eq
   819 
   820 Adaptions may be required in the following cases:
   821 
   822 a) User-defined constants using any of the names "plus", "minus", "times",
   823 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   824 may go wrong.
   825 INCOMPATIBILITY: use more specific names.
   826 
   827 b) Variables named "plus", "minus", "times", "less", "less_eq"
   828 INCOMPATIBILITY: use more specific names.
   829 
   830 c) Permutative equations (e.g. "a + b = b + a")
   831 Since the change of names also changes the order of terms, permutative
   832 rewrite rules may get applied in a different order. Experience shows that
   833 this is rarely the case (only two adaptions in the whole Isabelle
   834 distribution).
   835 INCOMPATIBILITY: rewrite proofs
   836 
   837 d) ML code directly refering to constant names
   838 This in general only affects hand-written proof tactics, simprocs and so on.
   839 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   840 of const_name ML antiquotations.
   841 
   842 * Relations less (<) and less_eq (<=) are also available on type bool.
   843 Modified syntax to disallow nesting without explicit parentheses,
   844 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   845 
   846 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   847 
   848 * Relation composition operator "op O" now has precedence 75 and binds
   849 stronger than union and intersection. INCOMPATIBILITY.
   850 
   851 * The old set interval syntax "{m..n(}" (and relatives) has been
   852 removed.  Use "{m..<n}" (and relatives) instead.
   853 
   854 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   855 "t = s" to False (by simproc "neq_simproc").  For backward
   856 compatibility this can be disabled by ML "reset use_neq_simproc".
   857 
   858 * "m dvd n" where m and n are numbers is evaluated to True/False by
   859 simp.
   860 
   861 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   862 
   863 * Theorem setsum_mult renamed to setsum_right_distrib.
   864 
   865 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   866 ``rule'' method.
   867 
   868 * Reimplemented methods ``sat'' and ``satx'', with several
   869 improvements: goals no longer need to be stated as "<prems> ==>
   870 False", equivalences (i.e. "=" on type bool) are handled, variable
   871 names of the form "lit_<n>" are no longer reserved, significant
   872 speedup.
   873 
   874 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   875 zChaff is still supported as well.
   876 
   877 * 'inductive' and 'datatype': provide projections of mutual rules,
   878 bundled as foo_bar.inducts;
   879 
   880 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   881 Library.
   882 
   883 * Library: moved theory Accessible_Part to main HOL.
   884 
   885 * Library: added theory Coinductive_List of potentially infinite lists
   886 as greatest fixed-point.
   887 
   888 * Library: added theory AssocList which implements (finite) maps as
   889 association lists.
   890 
   891 * Added proof method ``evaluation'' for efficiently solving a goal
   892 (i.e. a boolean expression) by compiling it to ML. The goal is
   893 "proved" (via an oracle) if it evaluates to True.
   894 
   895 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   896 also when invoked by the simplifier.  This results in the simplifier
   897 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   898 fast_arith_split_limit to 0 to obtain the old behavior.
   899 
   900 * Support for hex (0x20) and binary (0b1001) numerals.
   901 
   902 * New method: reify eqs (t), where eqs are equations for an
   903 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   904 parameter, computes a term s::'b and a list xs::'a list and proves the
   905 theorem I xs s = t. This is also known as reification or quoting. The
   906 resulting theorem is applied to the subgoal to substitute t with I xs
   907 s.  If t is omitted, the subgoal itself is reified.
   908 
   909 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   910 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   911 where f is supposed to be a computable function (in the sense of code
   912 generattion). The method uses reify to compute s and xs as above then
   913 applies corr_thm and uses normalization by evaluation to "prove" f s =
   914 r and finally gets the theorem t = r, which is again applied to the
   915 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   916 
   917 * Reflection: Automatic refification now handels binding, an example
   918 is available in HOL/ex/ReflectionEx.thy
   919 
   920 
   921 *** HOL-Algebra ***
   922 
   923 * Formalisation of ideals and the quotient construction over rings.
   924 
   925 * Order and lattice theory no longer based on records.
   926 INCOMPATIBILITY.
   927 
   928 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   929 greatest_closed.  INCOMPATIBILITY.
   930 
   931 * Method algebra is now set up via an attribute.  For examples see
   932 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   933 of algebraic structures.
   934 
   935 * Renamed theory CRing to Ring.
   936 
   937 
   938 *** HOL-Complex ***
   939 
   940 * Theory Real: new method ferrack implements quantifier elimination
   941 for linear arithmetic over the reals. The quantifier elimination
   942 feature is used only for decision, for compatibility with arith. This
   943 means a goal is either solved or left unchanged, no simplification.
   944 
   945 * Hyperreal: Functions root and sqrt are now defined on negative real
   946 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
   947 Nonnegativity side conditions have been removed from many lemmas, so
   948 that more subgoals may now be solved by simplification; potential
   949 INCOMPATIBILITY.
   950 
   951 * Real: New axiomatic classes formalize real normed vector spaces and
   952 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   953 and norm :: 'a => real.
   954 
   955 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   956 from reals into other types. The overloaded constant Reals :: 'a set
   957 is now defined as range of_real; potential INCOMPATIBILITY.
   958 
   959 * Real: ML code generation is supported now and hence also quickcheck.
   960 Reals are implemented as arbitrary precision rationals.
   961 
   962 * Hyperreal: Several constants that previously worked only for the
   963 reals have been generalized, so they now work over arbitrary vector
   964 spaces. Type annotations may need to be added in some cases; potential
   965 INCOMPATIBILITY.
   966 
   967   Infinitesimal  :: ('a::real_normed_vector) star set
   968   HFinite        :: ('a::real_normed_vector) star set
   969   HInfinite      :: ('a::real_normed_vector) star set
   970   approx         :: ('a::real_normed_vector) star => 'a star => bool
   971   monad          :: ('a::real_normed_vector) star => 'a star set
   972   galaxy         :: ('a::real_normed_vector) star => 'a star set
   973   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
   974   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   975   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   976   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   977   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   978   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   979   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   980   sgn            :: 'a::real_normed_vector => 'a
   981   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
   982 
   983 * Complex: Some complex-specific constants are now abbreviations for
   984 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   985 hnorm.  Other constants have been entirely removed in favor of the
   986 polymorphic versions (INCOMPATIBILITY):
   987 
   988   approx        <-- capprox
   989   HFinite       <-- CFinite
   990   HInfinite     <-- CInfinite
   991   Infinitesimal <-- CInfinitesimal
   992   monad         <-- cmonad
   993   galaxy        <-- cgalaxy
   994   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   995   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   996   (ns)deriv     <-- (ns)cderiv
   997 
   998 
   999 *** ML ***
  1000 
  1001 * Generic arithmetic modules: Tools/integer.ML, Tools/rat.ML, Tools/float.ML
  1002 
  1003 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1004 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1005 init only required for impure data.  INCOMPATIBILITY: empty really
  1006 need to be empty (no dependencies on theory content!)
  1007 
  1008 * ML within Isar: antiquotations allow to embed statically-checked
  1009 formal entities in the source, referring to the context available at
  1010 compile-time.  For example:
  1011 
  1012 ML {* @{typ "'a => 'b"} *}
  1013 ML {* @{term "%x. x"} *}
  1014 ML {* @{prop "x == y"} *}
  1015 ML {* @{ctyp "'a => 'b"} *}
  1016 ML {* @{cterm "%x. x"} *}
  1017 ML {* @{cprop "x == y"} *}
  1018 ML {* @{thm asm_rl} *}
  1019 ML {* @{thms asm_rl} *}
  1020 ML {* @{const_name c} *}
  1021 ML {* @{const_syntax c} *}
  1022 ML {* @{context} *}
  1023 ML {* @{theory} *}
  1024 ML {* @{theory Pure} *}
  1025 ML {* @{simpset} *}
  1026 ML {* @{claset} *}
  1027 ML {* @{clasimpset} *}
  1028 
  1029 The same works for sources being ``used'' within an Isar context.
  1030 
  1031 * ML in Isar: improved error reporting; extra verbosity with
  1032 Toplevel.debug enabled.
  1033 
  1034 * Pure/library:
  1035 
  1036   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1037   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1038 
  1039 The semantics of "burrow" is: "take a function with *simulatanously*
  1040 transforms a list of value, and apply it *simulatanously* to a list of
  1041 list of values of the appropriate type". Compare this with "map" which
  1042 would *not* apply its argument function simulatanously but in
  1043 sequence; "fold_burrow" has an additional context.
  1044 
  1045 * Pure/library: functions map2 and fold2 with curried syntax for
  1046 simultanous mapping and folding:
  1047 
  1048     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1049     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1050 
  1051 * Pure/library: indexed lists - some functions in the Isabelle library
  1052 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1053 given more convenient names and signatures reminiscent of similar
  1054 functions for alists, tables, etc:
  1055 
  1056   val nth: 'a list -> int -> 'a 
  1057   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1058   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1059 
  1060 Note that fold_index starts counting at index 0, not 1 like foldln
  1061 used to.
  1062 
  1063 * Pure/library: added general ``divide_and_conquer'' combinator on
  1064 lists.
  1065 
  1066 * Pure/General/table.ML: the join operations now works via exceptions
  1067 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1068 admits slightly more efficient complex applications.
  1069 
  1070 * Pure: datatype Context.generic joins theory/Proof.context and
  1071 provides some facilities for code that works in either kind of
  1072 context, notably GenericDataFun for uniform theory and proof data.
  1073 
  1074 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1075 use Context.generic instead of just theory.
  1076 
  1077 * Pure: simplified internal attribute type, which is now always
  1078 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1079 vs. local (Proof.context) attributes have been discontinued, while
  1080 minimizing code duplication.  Thm.rule_attribute and
  1081 Thm.declaration_attribute build canonical attributes; see also
  1082 structure Context for further operations on Context.generic, notably
  1083 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1084 declarations and definitions.
  1085 
  1086 * Pure/kernel: consts certification ignores sort constraints given in
  1087 signature declarations.  (This information is not relevant to the
  1088 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1089 potential INCOMPATIBILITY.
  1090 
  1091 * Pure: axiomatic type classes are now purely definitional, with
  1092 explicit proofs of class axioms and super class relations performed
  1093 internally.  See Pure/axclass.ML for the main internal interfaces --
  1094 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1095 AxClass.axiomatize_class/classrel/arity supercede
  1096 Sign.add_classes/classrel/arities.
  1097 
  1098 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1099 global/local versions on theory vs. Proof.context have been
  1100 discontinued; Attrib.syntax and Method.syntax have been adapted
  1101 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1102 attributes, methods, etc.
  1103 
  1104 * Pure: several functions of signature "... -> theory -> theory * ..."
  1105 have been reoriented to "... -> theory -> ... * theory" in order to
  1106 allow natural usage in combination with the ||>, ||>>, |-> and
  1107 fold_map combinators.
  1108 
  1109 * Pure: official theorem names (closed derivations) and additional
  1110 comments (tags) are now strictly separate.  Name hints -- which are
  1111 maintained as tags -- may be attached any time without affecting the
  1112 derivation.
  1113 
  1114 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1115 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1116 achieve the old behaviour.
  1117 
  1118 * Pure: the "Goal" constant is now called "prop", supporting a
  1119 slightly more general idea of ``protecting'' meta-level rule
  1120 statements.
  1121 
  1122 * Pure: Logic.(un)varify only works in a global context, which is now
  1123 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1124 Logic.legacy_(un)varify as temporary workaround.
  1125 
  1126 * Pure: structure Name provides scalable operations for generating
  1127 internal variable names, notably Name.variants etc.  This replaces
  1128 some popular functions from term.ML:
  1129 
  1130   Term.variant		->  Name.variant
  1131   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1132   Term.invent_names	->  Name.invent_list
  1133 
  1134 Note that low-level renaming rarely occurs in new code -- operations
  1135 from structure Variable are used instead (see below).
  1136 
  1137 * Pure: structure Variable provides fundamental operations for proper
  1138 treatment of fixed/schematic variables in a context.  For example,
  1139 Variable.import introduces fixes for schematics of given facts and
  1140 Variable.export reverses the effect (up to renaming) -- this replaces
  1141 various freeze_thaw operations.
  1142 
  1143 * Pure: structure Goal provides simple interfaces for
  1144 init/conclude/finish and tactical prove operations (replacing former
  1145 Tactic.prove).  Goal.prove is the canonical way to prove results
  1146 within a given context; Goal.prove_global is a degraded version for
  1147 theory level goals, including a global Drule.standard.  Note that
  1148 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1149 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1150 in a locale context).
  1151 
  1152 * Isar: simplified treatment of user-level errors, using exception
  1153 ERROR of string uniformly.  Function error now merely raises ERROR,
  1154 without any side effect on output channels.  The Isar toplevel takes
  1155 care of proper display of ERROR exceptions.  ML code may use plain
  1156 handle/can/try; cat_error may be used to concatenate errors like this:
  1157 
  1158   ... handle ERROR msg => cat_error msg "..."
  1159 
  1160 Toplevel ML code (run directly or through the Isar toplevel) may be
  1161 embedded into the Isar toplevel with exception display/debug like
  1162 this:
  1163 
  1164   Isar.toplevel (fn () => ...)
  1165 
  1166 INCOMPATIBILITY, removed special transform_error facilities, removed
  1167 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1168 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1169 -- use plain ERROR instead.
  1170 
  1171 * Isar: theory setup now has type (theory -> theory), instead of a
  1172 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1173 
  1174 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1175 subject to ProofContext.debug/verbose flags.
  1176 
  1177 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1178 theory before entering a proof state.  Transactions now always see a
  1179 quasi-functional intermediate checkpoint, both in interactive and
  1180 batch mode.
  1181 
  1182 * Simplifier: the simpset of a running simplification process now
  1183 contains a proof context (cf. Simplifier.the_context), which is the
  1184 very context that the initial simpset has been retrieved from (by
  1185 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1186 (solver, looper etc.) may depend on arbitrary proof data.
  1187 
  1188 * Simplifier.inherit_context inherits the proof context (plus the
  1189 local bounds) of the current simplification process; any simproc
  1190 etc. that calls the Simplifier recursively should do this!  Removed
  1191 former Simplifier.inherit_bounds, which is already included here --
  1192 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1193 specify an explicit context using Simplifier.context/theory_context.
  1194 
  1195 * Simplifier/Classical Reasoner: more abstract interfaces
  1196 change_simpset/claset for modifying the simpset/claset reference of a
  1197 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1198 INCOMPATIBILITY.
  1199 
  1200 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1201 "Trueprop" etc.
  1202 
  1203 
  1204 *** System ***
  1205 
  1206 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1207 locations -- now includes the Isabelle version identifier as well.
  1208 This simplifies use of multiple Isabelle installations.
  1209 
  1210 * isabelle-process: option -S (secure mode) disables some critical
  1211 operations, notably runtime compilation and evaluation of ML source
  1212 code.
  1213 
  1214 
  1215 New in Isabelle2005 (October 2005)
  1216 ----------------------------------
  1217 
  1218 *** General ***
  1219 
  1220 * Theory headers: the new header syntax for Isar theories is
  1221 
  1222   theory <name>
  1223   imports <theory1> ... <theoryN>
  1224   uses <file1> ... <fileM>
  1225   begin
  1226 
  1227 where the 'uses' part is optional.  The previous syntax
  1228 
  1229   theory <name> = <theory1> + ... + <theoryN>:
  1230 
  1231 will disappear in the next release.  Use isatool fixheaders to convert
  1232 existing theory files.  Note that there is no change in ancient
  1233 non-Isar theories now, but these will disappear soon.
  1234 
  1235 * Theory loader: parent theories can now also be referred to via
  1236 relative and absolute paths.
  1237 
  1238 * Command 'find_theorems' searches for a list of criteria instead of a
  1239 list of constants. Known criteria are: intro, elim, dest, name:string,
  1240 simp:term, and any term. Criteria can be preceded by '-' to select
  1241 theorems that do not match. Intro, elim, dest select theorems that
  1242 match the current goal, name:s selects theorems whose fully qualified
  1243 name contain s, and simp:term selects all simplification rules whose
  1244 lhs match term.  Any other term is interpreted as pattern and selects
  1245 all theorems matching the pattern. Available in ProofGeneral under
  1246 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1247 
  1248   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1249 
  1250 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1251 matching the current goal as introduction rule and not having "HOL."
  1252 in their name (i.e. not being defined in theory HOL).
  1253 
  1254 * Command 'thms_containing' has been discontinued in favour of
  1255 'find_theorems'; INCOMPATIBILITY.
  1256 
  1257 * Communication with Proof General is now 8bit clean, which means that
  1258 Unicode text in UTF-8 encoding may be used within theory texts (both
  1259 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1260 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1261 
  1262   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1263   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1264 
  1265 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1266 Classical Reasoner.  Typical big applications run around 2 times
  1267 faster.
  1268 
  1269 
  1270 *** Document preparation ***
  1271 
  1272 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1273 of raw sources.  Only those symbols that do not require additional
  1274 LaTeX packages (depending on comments in isabellesym.sty) are
  1275 displayed properly, everything else is left verbatim.  isatool display
  1276 and isatool print are used as front ends (these are subject to the
  1277 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1278 
  1279 * Command tags control specific markup of certain regions of text,
  1280 notably folding and hiding.  Predefined tags include "theory" (for
  1281 theory begin and end), "proof" for proof commands, and "ML" for
  1282 commands involving ML code; the additional tags "visible" and
  1283 "invisible" are unused by default.  Users may give explicit tag
  1284 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1285 interpretation of tags is determined by the LaTeX job during document
  1286 preparation: see option -V of isatool usedir, or options -n and -t of
  1287 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1288 \isadroptag.
  1289 
  1290 Several document versions may be produced at the same time via isatool
  1291 usedir (the generated index.html will link all of them).  Typical
  1292 specifications include ''-V document=theory,proof,ML'' to present
  1293 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1294 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1295 these parts without any formal replacement text.  The Isabelle site
  1296 default settings produce ''document'' and ''outline'' versions as
  1297 specified above.
  1298 
  1299 * Several new antiquotations:
  1300 
  1301   @{term_type term} prints a term with its type annotated;
  1302 
  1303   @{typeof term} prints the type of a term;
  1304 
  1305   @{const const} is the same as @{term const}, but checks that the
  1306   argument is a known logical constant;
  1307 
  1308   @{term_style style term} and @{thm_style style thm} print a term or
  1309   theorem applying a "style" to it
  1310 
  1311   @{ML text}
  1312 
  1313 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1314 definitions, equations, inequations etc., 'concl' printing only the
  1315 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1316 to print the specified premise.  TermStyle.add_style provides an ML
  1317 interface for introducing further styles.  See also the "LaTeX Sugar"
  1318 document practical applications.  The ML antiquotation prints
  1319 type-checked ML expressions verbatim.
  1320 
  1321 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1322 and 'text' support optional locale specification '(in loc)', which
  1323 specifies the default context for interpreting antiquotations.  For
  1324 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1325 
  1326 * Option 'locale=NAME' of antiquotations specifies an alternative
  1327 context interpreting the subsequent argument.  For example: @{thm
  1328 [locale=lattice] inf_assoc}.
  1329 
  1330 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1331 a proof context.
  1332 
  1333 * Proper output of antiquotations for theory commands involving a
  1334 proof context (such as 'locale' or 'theorem (in loc) ...').
  1335 
  1336 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1337 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1338 
  1339 * isatool usedir: new option -C (default true) controls whether option
  1340 -D should include a copy of the original document directory; -C false
  1341 prevents unwanted effects such as copying of administrative CVS data.
  1342 
  1343 
  1344 *** Pure ***
  1345 
  1346 * Considerably improved version of 'constdefs' command.  Now performs
  1347 automatic type-inference of declared constants; additional support for
  1348 local structure declarations (cf. locales and HOL records), see also
  1349 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1350 sequential dependencies of definitions within a single 'constdefs'
  1351 section; moreover, the declared name needs to be an identifier.  If
  1352 all fails, consider to fall back on 'consts' and 'defs' separately.
  1353 
  1354 * Improved indexed syntax and implicit structures.  First of all,
  1355 indexed syntax provides a notational device for subscripted
  1356 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1357 expressions.  Secondly, in a local context with structure
  1358 declarations, number indexes \<^sub>n or the empty index (default
  1359 number 1) refer to a certain fixed variable implicitly; option
  1360 show_structs controls printing of implicit structures.  Typical
  1361 applications of these concepts involve record types and locales.
  1362 
  1363 * New command 'no_syntax' removes grammar declarations (and
  1364 translations) resulting from the given syntax specification, which is
  1365 interpreted in the same manner as for the 'syntax' command.
  1366 
  1367 * 'Advanced' translation functions (parse_translation etc.) may depend
  1368 on the signature of the theory context being presently used for
  1369 parsing/printing, see also isar-ref manual.
  1370 
  1371 * Improved 'oracle' command provides a type-safe interface to turn an
  1372 ML expression of type theory -> T -> term into a primitive rule of
  1373 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1374 is already included here); see also FOL/ex/IffExample.thy;
  1375 INCOMPATIBILITY.
  1376 
  1377 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1378 before); "cI" is no longer bound, use "c.intro" instead.
  1379 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1380 axclasses vs. locales.
  1381 
  1382 * Improved internal renaming of symbolic identifiers -- attach primes
  1383 instead of base 26 numbers.
  1384 
  1385 * New flag show_question_marks controls printing of leading question
  1386 marks in schematic variable names.
  1387 
  1388 * In schematic variable names, *any* symbol following \<^isub> or
  1389 \<^isup> is now treated as part of the base name.  For example, the
  1390 following works without printing of awkward ".0" indexes:
  1391 
  1392   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1393     by simp
  1394 
  1395 * Inner syntax includes (*(*nested*) comments*).
  1396 
  1397 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1398 annotations as "(00...)".
  1399 
  1400 * Clear separation of logical types and nonterminals, where the latter
  1401 may only occur in 'syntax' specifications or type abbreviations.
  1402 Before that distinction was only partially implemented via type class
  1403 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1404 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1405 exotic syntax specifications may require further adaption
  1406 (e.g. Cube/Cube.thy).
  1407 
  1408 * Removed obsolete type class "logic", use the top sort {} instead.
  1409 Note that non-logical types should be declared as 'nonterminals'
  1410 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1411 specifications.
  1412 
  1413 * Attributes 'induct' and 'cases': type or set names may now be
  1414 locally fixed variables as well.
  1415 
  1416 * Simplifier: can now control the depth to which conditional rewriting
  1417 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1418 Limit.
  1419 
  1420 * Simplifier: simplification procedures may now take the current
  1421 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1422 interface), which is very useful for calling the Simplifier
  1423 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1424 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1425 low-level mk_simproc no longer applies Logic.varify internally, to
  1426 allow for use in a context of fixed variables.
  1427 
  1428 * thin_tac now works even if the assumption being deleted contains !!
  1429 or ==>.  More generally, erule now works even if the major premise of
  1430 the elimination rule contains !! or ==>.
  1431 
  1432 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1433 
  1434 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1435 from Pure, which contains all common declarations already.  Both
  1436 theories are defined via plain Isabelle/Isar .thy files.
  1437 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1438 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1439 use isatool fixcpure to adapt your theory and ML sources.
  1440 
  1441 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1442 selections of theorems in named facts via index ranges.
  1443 
  1444 * 'print_theorems': in theory mode, really print the difference
  1445 wrt. the last state (works for interactive theory development only),
  1446 in proof mode print all local facts (cf. 'print_facts');
  1447 
  1448 * 'hide': option '(open)' hides only base names.
  1449 
  1450 * More efficient treatment of intermediate checkpoints in interactive
  1451 theory development.
  1452 
  1453 * Code generator is now invoked via code_module (incremental code
  1454 generation) and code_library (modular code generation, ML structures
  1455 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1456 must be quoted when used as identifiers.
  1457 
  1458 * New 'value' command for reading, evaluating and printing terms using
  1459 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1460 quoted when used as identifier.
  1461 
  1462 
  1463 *** Locales ***
  1464 
  1465 * New commands for the interpretation of locale expressions in
  1466 theories (1), locales (2) and proof contexts (3).  These generate
  1467 proof obligations from the expression specification.  After the
  1468 obligations have been discharged, theorems of the expression are added
  1469 to the theory, target locale or proof context.  The synopsis of the
  1470 commands is a follows:
  1471 
  1472   (1) interpretation expr inst
  1473   (2) interpretation target < expr
  1474   (3) interpret expr inst
  1475 
  1476 Interpretation in theories and proof contexts require a parameter
  1477 instantiation of terms from the current context.  This is applied to
  1478 specifications and theorems of the interpreted expression.
  1479 Interpretation in locales only permits parameter renaming through the
  1480 locale expression.  Interpretation is smart in that interpretations
  1481 that are active already do not occur in proof obligations, neither are
  1482 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1483 inspect active interpretations of a particular locale.  For details,
  1484 see the Isar Reference manual.  Examples can be found in
  1485 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1486 
  1487 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1488 'interpret' instead.
  1489 
  1490 * New context element 'constrains' for adding type constraints to
  1491 parameters.
  1492 
  1493 * Context expressions: renaming of parameters with syntax
  1494 redeclaration.
  1495 
  1496 * Locale declaration: 'includes' disallowed.
  1497 
  1498 * Proper static binding of attribute syntax -- i.e. types / terms /
  1499 facts mentioned as arguments are always those of the locale definition
  1500 context, independently of the context of later invocations.  Moreover,
  1501 locale operations (renaming and type / term instantiation) are applied
  1502 to attribute arguments as expected.
  1503 
  1504 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1505 actual attributes; rare situations may require Attrib.attribute to
  1506 embed those attributes into Attrib.src that lack concrete syntax.
  1507 Attribute implementations need to cooperate properly with the static
  1508 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1509 Attrib.XXX_thm etc. already do the right thing without further
  1510 intervention.  Only unusual applications -- such as "where" or "of"
  1511 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1512 on the context and the facts involved -- may have to assign parsed
  1513 values to argument tokens explicitly.
  1514 
  1515 * Changed parameter management in theorem generation for long goal
  1516 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1517 theorem statement in rare situations.
  1518 
  1519 * Locale inspection command 'print_locale' omits notes elements.  Use
  1520 'print_locale!' to have them included in the output.
  1521 
  1522 
  1523 *** Provers ***
  1524 
  1525 * Provers/hypsubst.ML: improved version of the subst method, for
  1526 single-step rewriting: it now works in bound variable contexts. New is
  1527 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1528 rewrite a different subterm than the original subst method, which is
  1529 still available as 'simplesubst'.
  1530 
  1531 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1532 and quasi orders.
  1533 
  1534 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1535 reflexive-transitive closure of relations.
  1536 
  1537 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1538 limit (previously hard-coded with a value of 20) user-definable.
  1539 
  1540 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1541 is peformed already.  Object-logics merely need to finish their
  1542 initial simpset configuration as before.  INCOMPATIBILITY.
  1543 
  1544 
  1545 *** HOL ***
  1546 
  1547 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1548 
  1549   syntax (epsilon)
  1550     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1551 
  1552 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1553 and x-symbol; use option '-m epsilon' to get it actually printed.
  1554 Moreover, the mathematically important symbolic identifier \<epsilon>
  1555 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1556 
  1557 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1558 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1559 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1560 support corresponding Isar calculations.
  1561 
  1562 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1563 instead of ":".
  1564 
  1565 * theory SetInterval: changed the syntax for open intervals:
  1566 
  1567   Old       New
  1568   {..n(}    {..<n}
  1569   {)n..}    {n<..}
  1570   {m..n(}   {m..<n}
  1571   {)m..n}   {m<..n}
  1572   {)m..n(}  {m<..<n}
  1573 
  1574 The old syntax is still supported but will disappear in the next
  1575 release.  For conversion use the following Emacs search and replace
  1576 patterns (these are not perfect but work quite well):
  1577 
  1578   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1579   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1580 
  1581 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1582 equalities in commutative rings; method 'algebra' provides a generic
  1583 interface.
  1584 
  1585 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1586 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1587 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1588 be a tuple pattern.
  1589 
  1590 Some new syntax forms are available:
  1591 
  1592   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1593   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1594   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1595   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1596 
  1597 The latter form "\<Sum>x < k. e" used to be based on a separate
  1598 function "Summation", which has been discontinued.
  1599 
  1600 * theory Finite_Set: in structured induction proofs, the insert case
  1601 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1602 (insert F x)'.
  1603 
  1604 * The 'refute' command has been extended to support a much larger
  1605 fragment of HOL, including axiomatic type classes, constdefs and
  1606 typedefs, inductive datatypes and recursion.
  1607 
  1608 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1609 Requires zChaff with proof generation to be installed.  See
  1610 HOL/ex/SAT_Examples.thy for examples.
  1611 
  1612 * Datatype induction via method 'induct' now preserves the name of the
  1613 induction variable. For example, when proving P(xs::'a list) by
  1614 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1615 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1616 in unstructured proof scripts.
  1617 
  1618 * Reworked implementation of records.  Improved scalability for
  1619 records with many fields, avoiding performance problems for type
  1620 inference. Records are no longer composed of nested field types, but
  1621 of nested extension types. Therefore the record type only grows linear
  1622 in the number of extensions and not in the number of fields.  The
  1623 top-level (users) view on records is preserved.  Potential
  1624 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1625 old record representation. The type generated for a record is called
  1626 <record_name>_ext_type.
  1627 
  1628 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1629 proofs triggered by a record definition or a simproc (if
  1630 quick_and_dirty is enabled).  Definitions of large records can take
  1631 quite long.
  1632 
  1633 New simproc record_upd_simproc for simplification of multiple record
  1634 updates enabled by default.  Moreover, trivial updates are also
  1635 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1636 occasionally, since simplification is more powerful by default.
  1637 
  1638 * typedef: proper support for polymorphic sets, which contain extra
  1639 type-variables in the term.
  1640 
  1641 * Simplifier: automatically reasons about transitivity chains
  1642 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1643 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1644 old proofs break occasionally as simplification may now solve more
  1645 goals than previously.
  1646 
  1647 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1648 present.  Works for all partial orders (class "order"), in particular
  1649 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1650 just like y <= x.
  1651 
  1652 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1653 bound variable or a constant then the let is unfolded.  Otherwise
  1654 first a is simplified to b, and then f b is simplified to g. If
  1655 possible we abstract b from g arriving at "let x = b in h x",
  1656 otherwise we unfold the let and arrive at g.  The simproc can be
  1657 enabled/disabled by the reference use_let_simproc.  Potential
  1658 INCOMPATIBILITY since simplification is more powerful by default.
  1659 
  1660 * Classical reasoning: the meson method now accepts theorems as arguments.
  1661 
  1662 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1663 jobs to provide advice on the provability of subgoals.
  1664 
  1665 * Theory OrderedGroup and Ring_and_Field: various additions and
  1666 improvements to faciliate calculations involving equalities and
  1667 inequalities.
  1668 
  1669 The following theorems have been eliminated or modified
  1670 (INCOMPATIBILITY):
  1671 
  1672   abs_eq             now named abs_of_nonneg
  1673   abs_of_ge_0        now named abs_of_nonneg
  1674   abs_minus_eq       now named abs_of_nonpos
  1675   imp_abs_id         now named abs_of_nonneg
  1676   imp_abs_neg_id     now named abs_of_nonpos
  1677   mult_pos           now named mult_pos_pos
  1678   mult_pos_le        now named mult_nonneg_nonneg
  1679   mult_pos_neg_le    now named mult_nonneg_nonpos
  1680   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1681   mult_neg           now named mult_neg_neg
  1682   mult_neg_le        now named mult_nonpos_nonpos
  1683 
  1684 * The following lemmas in Ring_and_Field have been added to the simplifier:
  1685      
  1686      zero_le_square
  1687      not_square_less_zero 
  1688 
  1689   The following lemmas have been deleted from Real/RealPow:
  1690   
  1691      realpow_zero_zero
  1692      realpow_two
  1693      realpow_less
  1694      zero_le_power
  1695      realpow_two_le
  1696      abs_realpow_two
  1697      realpow_two_abs     
  1698 
  1699 * Theory Parity: added rules for simplifying exponents.
  1700 
  1701 * Theory List:
  1702 
  1703 The following theorems have been eliminated or modified
  1704 (INCOMPATIBILITY):
  1705 
  1706   list_all_Nil       now named list_all.simps(1)
  1707   list_all_Cons      now named list_all.simps(2)
  1708   list_all_conv      now named list_all_iff
  1709   set_mem_eq         now named mem_iff
  1710 
  1711 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1712 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1713 
  1714 
  1715 *** HOL-Complex ***
  1716 
  1717 * Theory RealDef: better support for embedding natural numbers and
  1718 integers in the reals.
  1719 
  1720 The following theorems have been eliminated or modified
  1721 (INCOMPATIBILITY):
  1722 
  1723   exp_ge_add_one_self  now requires no hypotheses
  1724   real_of_int_add      reversed direction of equality (use [symmetric])
  1725   real_of_int_minus    reversed direction of equality (use [symmetric])
  1726   real_of_int_diff     reversed direction of equality (use [symmetric])
  1727   real_of_int_mult     reversed direction of equality (use [symmetric])
  1728 
  1729 * Theory RComplete: expanded support for floor and ceiling functions.
  1730 
  1731 * Theory Ln is new, with properties of the natural logarithm
  1732 
  1733 * Hyperreal: There is a new type constructor "star" for making
  1734 nonstandard types.  The old type names are now type synonyms:
  1735 
  1736   hypreal = real star
  1737   hypnat = nat star
  1738   hcomplex = complex star
  1739 
  1740 * Hyperreal: Many groups of similarly-defined constants have been
  1741 replaced by polymorphic versions (INCOMPATIBILITY):
  1742 
  1743   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1744 
  1745   starset      <-- starsetNat, starsetC
  1746   *s*          <-- *sNat*, *sc*
  1747   starset_n    <-- starsetNat_n, starsetC_n
  1748   *sn*         <-- *sNatn*, *scn*
  1749   InternalSets <-- InternalNatSets, InternalCSets
  1750 
  1751   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1752   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1753   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1754   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1755   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1756 
  1757 * Hyperreal: Many type-specific theorems have been removed in favor of
  1758 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1759 
  1760   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1761   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1762   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1763   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1764   right_minus <-- hypreal_add_minus
  1765   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1766   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1767   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1768   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1769   mult_1_right <-- hcomplex_mult_one_right
  1770   mult_zero_left <-- hcomplex_mult_zero_left
  1771   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1772   right_distrib <-- hypnat_add_mult_distrib2
  1773   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1774   right_inverse <-- hypreal_mult_inverse
  1775   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1776   order_refl <-- {hypreal,hypnat}_le_refl
  1777   order_trans <-- {hypreal,hypnat}_le_trans
  1778   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1779   order_less_le <-- {hypreal,hypnat}_less_le
  1780   linorder_linear <-- {hypreal,hypnat}_le_linear
  1781   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1782   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1783   add_nonneg_nonneg <-- hypreal_le_add_order
  1784 
  1785 * Hyperreal: Separate theorems having to do with type-specific
  1786 versions of constants have been merged into theorems that apply to the
  1787 new polymorphic constants (INCOMPATIBILITY):
  1788 
  1789   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1790   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1791   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1792   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1793   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1794   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1795   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1796   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1797   STAR_diff <-- {STAR,STARC}_diff
  1798   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1799     STARC_hcomplex_of_complex}_image_subset
  1800   starset_n_Un <-- starset{Nat,C}_n_Un
  1801   starset_n_Int <-- starset{Nat,C}_n_Int
  1802   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1803   starset_n_diff <-- starset{Nat,C}_n_diff
  1804   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1805   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1806   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1807   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1808   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1809   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1810   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1811   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1812   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1813   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1814   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1815   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1816   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1817   starfun_diff <-- starfun{C,RC,CR}_diff
  1818   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1819   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1820   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1821   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1822   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1823   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1824   starfun_Id <-- starfunC_Id
  1825   starfun_approx <-- starfun{Nat,CR}_approx
  1826   starfun_capprox <-- starfun{C,RC}_capprox
  1827   starfun_abs <-- starfunNat_rabs
  1828   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1829   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1830   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1831   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1832   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1833   starfun_add_approx <-- starfunCR_add_approx
  1834   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1835   starfun_divide <-- starfun{C,CR,RC}_divide
  1836   starfun_n <-- starfun{Nat,C}_n
  1837   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1838   starfun_n_add <-- starfun{Nat,C}_n_add
  1839   starfun_n_add_minus <-- starfunNat_n_add_minus
  1840   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1841   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1842   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1843 
  1844   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1845   star_n_minus <-- {hypreal,hcomplex}_minus
  1846   star_n_diff <-- {hypreal,hcomplex}_diff
  1847   star_n_mult <-- {hypreal,hcomplex}_mult
  1848   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1849   star_n_le <-- {hypreal,hypnat}_le
  1850   star_n_less <-- {hypreal,hypnat}_less
  1851   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1852   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1853   star_n_abs <-- hypreal_hrabs
  1854   star_n_divide <-- hcomplex_divide
  1855 
  1856   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1857   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1858   star_of_diff <-- hypreal_of_real_diff
  1859   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1860   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1861   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1862   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1863   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1864   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1865   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1866   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1867   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1868   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1869   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1870   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1871   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1872   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1873   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1874   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1875   star_of_power <-- hypreal_of_real_power
  1876   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1877 
  1878 * Hyperreal: new method "transfer" that implements the transfer
  1879 principle of nonstandard analysis. With a subgoal that mentions
  1880 nonstandard types like "'a star", the command "apply transfer"
  1881 replaces it with an equivalent one that mentions only standard types.
  1882 To be successful, all free variables must have standard types; non-
  1883 standard variables must have explicit universal quantifiers.
  1884 
  1885 * Hyperreal: A theory of Taylor series.
  1886 
  1887 
  1888 *** HOLCF ***
  1889 
  1890 * Discontinued special version of 'constdefs' (which used to support
  1891 continuous functions) in favor of the general Pure one with full
  1892 type-inference.
  1893 
  1894 * New simplification procedure for solving continuity conditions; it
  1895 is much faster on terms with many nested lambda abstractions (cubic
  1896 instead of exponential time).
  1897 
  1898 * New syntax for domain package: selector names are now optional.
  1899 Parentheses should be omitted unless argument is lazy, for example:
  1900 
  1901   domain 'a stream = cons "'a" (lazy "'a stream")
  1902 
  1903 * New command 'fixrec' for defining recursive functions with pattern
  1904 matching; defining multiple functions with mutual recursion is also
  1905 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1906 sinr, or any data constructor defined by the domain package. The given
  1907 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1908 syntax and examples.
  1909 
  1910 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1911 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1912 but the proof obligation additionally includes an admissibility
  1913 requirement. The packages generate instances of class cpo or pcpo,
  1914 with continuity and strictness theorems for Rep and Abs.
  1915 
  1916 * HOLCF: Many theorems have been renamed according to a more standard naming
  1917 scheme (INCOMPATIBILITY):
  1918 
  1919   foo_inject:  "foo$x = foo$y ==> x = y"
  1920   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1921   foo_less:    "(foo$x << foo$y) = (x << y)"
  1922   foo_strict:  "foo$UU = UU"
  1923   foo_defined: "... ==> foo$x ~= UU"
  1924   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1925 
  1926 
  1927 *** ZF ***
  1928 
  1929 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1930 including the First Isomorphism Theorem (on quotienting by the kernel
  1931 of a homomorphism).
  1932 
  1933 * ZF/Simplifier: install second copy of type solver that actually
  1934 makes use of TC rules declared to Isar proof contexts (or locales);
  1935 the old version is still required for ML proof scripts.
  1936 
  1937 
  1938 *** Cube ***
  1939 
  1940 * Converted to Isar theory format; use locales instead of axiomatic
  1941 theories.
  1942 
  1943 
  1944 *** ML ***
  1945 
  1946 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1947 for ||>, ||>>, |>>,
  1948 
  1949 * Pure/library.ML no longer defines its own option datatype, but uses
  1950 that of the SML basis, which has constructors NONE and SOME instead of
  1951 None and Some, as well as exception Option.Option instead of OPTION.
  1952 The functions the, if_none, is_some, is_none have been adapted
  1953 accordingly, while Option.map replaces apsome.
  1954 
  1955 * Pure/library.ML: the exception LIST has been given up in favour of
  1956 the standard exceptions Empty and Subscript, as well as
  1957 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1958 superceded by the standard hd and tl functions etc.
  1959 
  1960 A number of basic list functions are no longer exported to the ML
  1961 toplevel, as they are variants of predefined functions.  The following
  1962 suggests how one can translate existing code:
  1963 
  1964     rev_append xs ys = List.revAppend (xs, ys)
  1965     nth_elem (i, xs) = List.nth (xs, i)
  1966     last_elem xs = List.last xs
  1967     flat xss = List.concat xss
  1968     seq fs = List.app fs
  1969     partition P xs = List.partition P xs
  1970     mapfilter f xs = List.mapPartial f xs
  1971 
  1972 * Pure/library.ML: several combinators for linear functional
  1973 transformations, notably reverse application and composition:
  1974 
  1975   x |> f                f #> g
  1976   (x, y) |-> f          f #-> g
  1977 
  1978 * Pure/library.ML: introduced/changed precedence of infix operators:
  1979 
  1980   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1981   infix 2 ?;
  1982   infix 3 o oo ooo oooo;
  1983   infix 4 ~~ upto downto;
  1984 
  1985 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1986 infix operators.
  1987 
  1988 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1989 fold_map support linear functional transformations and nesting.  For
  1990 example:
  1991 
  1992   fold f [x1, ..., xN] y =
  1993     y |> f x1 |> ... |> f xN
  1994 
  1995   (fold o fold) f [xs1, ..., xsN] y =
  1996     y |> fold f xs1 |> ... |> fold f xsN
  1997 
  1998   fold f [x1, ..., xN] =
  1999     f x1 #> ... #> f xN
  2000 
  2001   (fold o fold) f [xs1, ..., xsN] =
  2002     fold f xs1 #> ... #> fold f xsN
  2003 
  2004 * Pure/library.ML: the following selectors on type 'a option are
  2005 available:
  2006 
  2007   the:               'a option -> 'a  (*partial*)
  2008   these:             'a option -> 'a  where 'a = 'b list
  2009   the_default: 'a -> 'a option -> 'a
  2010   the_list:          'a option -> 'a list
  2011 
  2012 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2013 basic operations for association lists, following natural argument
  2014 order; moreover the explicit equality predicate passed here avoids
  2015 potentially expensive polymorphic runtime equality checks.
  2016 The old functions may be expressed as follows:
  2017 
  2018   assoc = uncurry (AList.lookup (op =))
  2019   assocs = these oo AList.lookup (op =)
  2020   overwrite = uncurry (AList.update (op =)) o swap
  2021 
  2022 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2023 
  2024   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2025   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2026 
  2027 replacing make_keylist and keyfilter (occassionally used)
  2028 Naive rewrites:
  2029 
  2030   make_keylist = AList.make
  2031   keyfilter = AList.find (op =)
  2032 
  2033 * eq_fst and eq_snd now take explicit equality parameter, thus
  2034   avoiding eqtypes. Naive rewrites:
  2035 
  2036     eq_fst = eq_fst (op =)
  2037     eq_snd = eq_snd (op =)
  2038 
  2039 * Removed deprecated apl and apr (rarely used).
  2040   Naive rewrites:
  2041 
  2042     apl (n, op) =>>= curry op n
  2043     apr (op, m) =>>= fn n => op (n, m)
  2044 
  2045 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2046 provides a reasonably efficient light-weight implementation of sets as
  2047 lists.
  2048 
  2049 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2050 few new operations; existing lookup and update are now curried to
  2051 follow natural argument order (for use with fold etc.);
  2052 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2053 
  2054 * Pure/General: output via the Isabelle channels of
  2055 writeln/warning/error etc. is now passed through Output.output, with a
  2056 hook for arbitrary transformations depending on the print_mode
  2057 (cf. Output.add_mode -- the first active mode that provides a output
  2058 function wins).  Already formatted output may be embedded into further
  2059 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2060 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2061 accommodate easy composition of diagnostic messages etc.  Programmers
  2062 rarely need to care about Output.output or Output.raw at all, with
  2063 some notable exceptions: Output.output is required when bypassing the
  2064 standard channels (writeln etc.), or in token translations to produce
  2065 properly formatted results; Output.raw is required when capturing
  2066 already output material that will eventually be presented to the user
  2067 a second time.  For the default print mode, both Output.output and
  2068 Output.raw have no effect.
  2069 
  2070 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2071 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2072 cumulative results are displayed at the end of a batch session.
  2073 
  2074 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2075 replaced by File.platform_path and File.shell_path (with appropriate
  2076 hooks).  This provides a clean interface for unusual systems where the
  2077 internal and external process view of file names are different.
  2078 
  2079 * Pure: more efficient orders for basic syntactic entities: added
  2080 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2081 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2082 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2083 orders now -- potential INCOMPATIBILITY for code that depends on a
  2084 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2085 Library.sort_strings on result).
  2086 
  2087 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2088 fold_types traverse types/terms from left to right, observing natural
  2089 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2090 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2091 
  2092 * Pure: name spaces have been refined, with significant changes of the
  2093 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2094 to extern(_table).  The plain name entry path is superceded by a
  2095 general 'naming' context, which also includes the 'policy' to produce
  2096 a fully qualified name and external accesses of a fully qualified
  2097 name; NameSpace.extend is superceded by context dependent
  2098 Sign.declare_name.  Several theory and proof context operations modify
  2099 the naming context.  Especially note Theory.restore_naming and
  2100 ProofContext.restore_naming to get back to a sane state; note that
  2101 Theory.add_path is no longer sufficient to recover from
  2102 Theory.absolute_path in particular.
  2103 
  2104 * Pure: new flags short_names (default false) and unique_names
  2105 (default true) for controlling output of qualified names.  If
  2106 short_names is set, names are printed unqualified.  If unique_names is
  2107 reset, the name prefix is reduced to the minimum required to achieve
  2108 the original result when interning again, even if there is an overlap
  2109 with earlier declarations.
  2110 
  2111 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2112 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2113 (useful for printing error messages).  INCOMPATIBILITY.
  2114 
  2115 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2116 Theory.theory are now identified, referring to the universal
  2117 Context.theory (see Pure/context.ML).  Actual signature and theory
  2118 content is managed as theory data.  The old code and interfaces were
  2119 spread over many files and structures; the new arrangement introduces
  2120 considerable INCOMPATIBILITY to gain more clarity:
  2121 
  2122   Context -- theory management operations (name, identity, inclusion,
  2123     parents, ancestors, merge, etc.), plus generic theory data;
  2124 
  2125   Sign -- logical signature and syntax operations (declaring consts,
  2126     types, etc.), plus certify/read for common entities;
  2127 
  2128   Theory -- logical theory operations (stating axioms, definitions,
  2129     oracles), plus a copy of logical signature operations (consts,
  2130     types, etc.); also a few basic management operations (Theory.copy,
  2131     Theory.merge, etc.)
  2132 
  2133 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2134 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2135 for convenience -- they merely return the theory.
  2136 
  2137 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2138 
  2139 * Pure: the Isar proof context type is already defined early in Pure
  2140 as Context.proof (note that ProofContext.context and Proof.context are
  2141 aliases, where the latter is the preferred name).  This enables other
  2142 Isabelle components to refer to that type even before Isar is present.
  2143 
  2144 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2145 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2146 any of these kinds.  For example, Sign.intern typeK is now
  2147 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2148 Theory.hide_types.  Also note that former
  2149 Theory.hide_classes/types/consts are now
  2150 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2151 internalize their arguments!  INCOMPATIBILITY.
  2152 
  2153 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2154 datatype thmref (with constructors Name and NameSelection) instead of
  2155 plain string -- INCOMPATIBILITY;
  2156 
  2157 * Pure: cases produced by proof methods specify options, where NONE
  2158 means to remove case bindings -- INCOMPATIBILITY in
  2159 (RAW_)METHOD_CASES.
  2160 
  2161 * Pure: the following operations retrieve axioms or theorems from a
  2162 theory node or theory hierarchy, respectively:
  2163 
  2164   Theory.axioms_of: theory -> (string * term) list
  2165   Theory.all_axioms_of: theory -> (string * term) list
  2166   PureThy.thms_of: theory -> (string * thm) list
  2167   PureThy.all_thms_of: theory -> (string * thm) list
  2168 
  2169 * Pure: print_tac now outputs the goal through the trace channel.
  2170 
  2171 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2172 Reference Toplevel.debug (default false) controls detailed printing
  2173 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2174 controls execution profiling -- set to 1 for time and 2 for space
  2175 (both increase the runtime).
  2176 
  2177 * Isar session: The initial use of ROOT.ML is now always timed,
  2178 i.e. the log will show the actual process times, in contrast to the
  2179 elapsed wall-clock time that the outer shell wrapper produces.
  2180 
  2181 * Simplifier: improved handling of bound variables (nameless
  2182 representation, avoid allocating new strings).  Simprocs that invoke
  2183 the Simplifier recursively should use Simplifier.inherit_bounds to
  2184 avoid local name clashes.  Failure to do so produces warnings
  2185 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2186 for further details.
  2187 
  2188 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2189 bindings for all theorems stored within a given theory; this may help
  2190 in porting non-Isar theories to Isar ones, while keeping ML proof
  2191 scripts for the time being.
  2192 
  2193 * ML operator HTML.with_charset specifies the charset begin used for
  2194 generated HTML files.  For example:
  2195 
  2196   HTML.with_charset "utf-8" use_thy "Hebrew";
  2197   HTML.with_charset "utf-8" use_thy "Chinese";
  2198 
  2199 
  2200 *** System ***
  2201 
  2202 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2203 isabelle, isatool etc.).
  2204 
  2205 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2206 isatool doc, isatool mkdir, display_drafts etc.).
  2207 
  2208 * isatool usedir: option -f allows specification of the ML file to be
  2209 used by Isabelle; default is ROOT.ML.
  2210 
  2211 * New isatool version outputs the version identifier of the Isabelle
  2212 distribution being used.
  2213 
  2214 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2215 (containing Boolean satisfiability problems) into Isabelle/HOL
  2216 theories.
  2217 
  2218 
  2219 
  2220 New in Isabelle2004 (April 2004)
  2221 --------------------------------
  2222 
  2223 *** General ***
  2224 
  2225 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2226   Replaces linorder.ML.
  2227 
  2228 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2229   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2230   (\<a>...\<z>), are now considered normal letters, and can therefore
  2231   be used anywhere where an ASCII letter (a...zA...Z) has until
  2232   now. COMPATIBILITY: This obviously changes the parsing of some
  2233   terms, especially where a symbol has been used as a binder, say
  2234   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2235   as an identifier.  Fix it by inserting a space around former
  2236   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2237   existing theory and ML files.
  2238 
  2239 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2240 
  2241 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2242   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2243   a normal (but invisible) letter. For multiple letter subscripts repeat
  2244   \<^isub> like this: x\<^isub>1\<^isub>2.
  2245 
  2246 * Pure: There are now sub-/superscripts that can span more than one
  2247   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2248   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2249   superscript. The new control characters are not identifier parts.
  2250 
  2251 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2252   content of "..." to the latex file instead of \isacntrl... . The "..."
  2253   may consist of any printable characters excluding the end bracket >.
  2254 
  2255 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2256   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2257   declare constants "final", which prevents their being given a definition
  2258   later.  It is useful for constants whose behaviour is fixed axiomatically
  2259   rather than definitionally, such as the meta-logic connectives.
  2260 
  2261 * Pure: 'instance' now handles general arities with general sorts
  2262   (i.e. intersections of classes),
  2263 
  2264 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2265   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2266   It can be changed to alter the colors/layout of generated pages.
  2267 
  2268 
  2269 *** Isar ***
  2270 
  2271 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2272   cut_tac, subgoal_tac and thin_tac:
  2273   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2274     locales are no longer forced to write Isar proof scripts.
  2275     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2276     emulations.
  2277   - INCOMPATIBILITY: names of variables to be instantiated may no
  2278     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2279     This is consistent with the instantiation attribute "where".
  2280 
  2281 * Attributes "where" and "of":
  2282   - Now take type variables of instantiated theorem into account when reading
  2283     the instantiation string.  This fixes a bug that caused instantiated
  2284     theorems to have too special types in some circumstances.
  2285   - "where" permits explicit instantiations of type variables.
  2286 
  2287 * Calculation commands "moreover" and "also" no longer interfere with
  2288   current facts ("this"), admitting arbitrary combinations with "then"
  2289   and derived forms.
  2290 
  2291 * Locales:
  2292   - Goal statements involving the context element "includes" no longer
  2293     generate theorems with internal delta predicates (those ending on
  2294     "_axioms") in the premise.
  2295     Resolve particular premise with <locale>.intro to obtain old form.
  2296   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2297     specification and "includes" elements in goal statement.
  2298   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2299     [intro?] and [elim?] (respectively) by default.
  2300   - Experimental command for instantiation of locales in proof contexts:
  2301         instantiate <label>[<attrs>]: <loc>
  2302     Instantiates locale <loc> and adds all its theorems to the current context
  2303     taking into account their attributes.  Label and attrs are optional
  2304     modifiers, like in theorem declarations.  If present, names of
  2305     instantiated theorems are qualified with <label>, and the attributes
  2306     <attrs> are applied after any attributes these theorems might have already.
  2307       If the locale has assumptions, a chained fact of the form
  2308     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2309     are derived.  The command does not support old-style locales declared
  2310     with "locale (open)".
  2311       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2312 
  2313 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2314   (Isar) contexts.
  2315 
  2316 
  2317 *** HOL ***
  2318 
  2319 * Proof import: new image HOL4 contains the imported library from
  2320   the HOL4 system with about 2500 theorems. It is imported by
  2321   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2322   can be used like any other Isabelle image.  See
  2323   HOL/Import/HOL/README for more information.
  2324 
  2325 * Simplifier:
  2326   - Much improved handling of linear and partial orders.
  2327     Reasoners for linear and partial orders are set up for type classes
  2328     "linorder" and "order" respectively, and are added to the default simpset
  2329     as solvers.  This means that the simplifier can build transitivity chains
  2330     to solve goals from the assumptions.
  2331   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2332     of blast or auto after simplification become unnecessary because the goal
  2333     is solved by simplification already.
  2334 
  2335 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2336     all proved in axiomatic type classes for semirings, rings and fields.
  2337 
  2338 * Numerics:
  2339   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2340     now formalized using the Ring_and_Field theory mentioned above.
  2341   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2342     than before, because now they are set up once in a generic manner.
  2343   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2344     Look for the general versions in Ring_and_Field (and Power if they concern
  2345     exponentiation).
  2346 
  2347 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2348 
  2349 * Records:
  2350   - Record types are now by default printed with their type abbreviation
  2351     instead of the list of all field types. This can be configured via
  2352     the reference "print_record_type_abbr".
  2353   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2354     (not enabled by default).
  2355   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2356     EX x. x = sel r to True (not enabled by default).
  2357   - Tactic "record_split_simp_tac" to split and simplify records added.
  2358 
  2359 * 'specification' command added, allowing for definition by
  2360   specification.  There is also an 'ax_specification' command that
  2361   introduces the new constants axiomatically.
  2362 
  2363 * arith(_tac) is now able to generate counterexamples for reals as well.
  2364 
  2365 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2366 
  2367 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2368   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2369 
  2370 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2371   matrix theory to linear programming.
  2372 
  2373 * Unions and Intersections:
  2374   The latex output syntax of UN and INT has been changed
  2375   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2376   i.e. the index formulae has become a subscript.
  2377   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2378 
  2379 * Unions and Intersections over Intervals:
  2380   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2381   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2382   like in normal math, and corresponding versions for < and for intersection.
  2383 
  2384 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2385   lexicographic dictonary ordering has been added as "lexord".
  2386 
  2387 * ML: the legacy theory structures Int and List have been removed. They had
  2388   conflicted with ML Basis Library structures having the same names.
  2389 
  2390 * 'refute' command added to search for (finite) countermodels.  Only works
  2391   for a fragment of HOL.  The installation of an external SAT solver is
  2392   highly recommended.  See "HOL/Refute.thy" for details.
  2393 
  2394 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2395   formulae under an assignment of free variables to random values.
  2396   In contrast to 'refute', it can deal with inductive datatypes,
  2397   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2398   for examples.
  2399 
  2400 
  2401 *** HOLCF ***
  2402 
  2403 * Streams now come with concatenation and are part of the HOLCF image
  2404 
  2405 
  2406 
  2407 New in Isabelle2003 (May 2003)
  2408 ------------------------------
  2409 
  2410 *** General ***
  2411 
  2412 * Provers/simplifier:
  2413 
  2414   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2415     Assumptions are now subject to complete mutual simplification,
  2416     not just from left to right. The simplifier now preserves
  2417     the order of assumptions.
  2418 
  2419     Potential INCOMPATIBILITY:
  2420 
  2421     -- simp sometimes diverges where the old version did
  2422        not, e.g. invoking simp on the goal
  2423 
  2424         [| P (f x); y = x; f x = f y |] ==> Q
  2425 
  2426        now gives rise to the infinite reduction sequence
  2427 
  2428         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2429 
  2430        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2431        kind of problem.
  2432 
  2433     -- Tactics combining classical reasoner and simplification (such as auto)
  2434        are also affected by this change, because many of them rely on
  2435        simp. They may sometimes diverge as well or yield a different numbers
  2436        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2437        in case of problems. Sometimes subsequent calls to the classical
  2438        reasoner will fail because a preceeding call to the simplifier too
  2439        eagerly simplified the goal, e.g. deleted redundant premises.
  2440 
  2441   - The simplifier trace now shows the names of the applied rewrite rules
  2442 
  2443   - You can limit the number of recursive invocations of the simplifier
  2444     during conditional rewriting (where the simplifie tries to solve the
  2445     conditions before applying the rewrite rule):
  2446     ML "simp_depth_limit := n"
  2447     where n is an integer. Thus you can force termination where previously
  2448     the simplifier would diverge.
  2449 
  2450   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2451 
  2452   - No longer aborts on failed congruence proof.  Instead, the
  2453     congruence is ignored.
  2454 
  2455 * Pure: New generic framework for extracting programs from constructive
  2456   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2457   as HOL/Extraction for some case studies.
  2458 
  2459 * Pure: The main goal of the proof state is no longer shown by default, only
  2460 the subgoals. This behaviour is controlled by a new flag.
  2461    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2462 (ML: Proof.show_main_goal).
  2463 
  2464 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2465 rules whose conclusion matches subgoal 1:
  2466       PG menu: Isabelle/Isar -> Show me -> matching rules
  2467 The rules are ordered by how closely they match the subgoal.
  2468 In particular, rules that solve a subgoal outright are displayed first
  2469 (or rather last, the way they are printed).
  2470 (ML: ProofGeneral.print_intros())
  2471 
  2472 * Pure: New flag trace_unify_fail causes unification to print
  2473 diagnostic information (PG: in trace buffer) when it fails. This is
  2474 useful for figuring out why single step proofs like rule, erule or
  2475 assumption failed.
  2476 
  2477 * Pure: Locale specifications now produce predicate definitions
  2478 according to the body of text (covering assumptions modulo local
  2479 definitions); predicate "loc_axioms" covers newly introduced text,
  2480 while "loc" is cumulative wrt. all included locale expressions; the
  2481 latter view is presented only on export into the global theory
  2482 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2483 on the old view without predicates;
  2484 
  2485 * Pure: predefined locales "var" and "struct" are useful for sharing
  2486 parameters (as in CASL, for example); just specify something like
  2487 ``var x + var y + struct M'' as import;
  2488 
  2489 * Pure: improved thms_containing: proper indexing of facts instead of
  2490 raw theorems; check validity of results wrt. current name space;
  2491 include local facts of proof configuration (also covers active
  2492 locales), cover fixed variables in index; may use "_" in term
  2493 specification; an optional limit for the number of printed facts may
  2494 be given (the default is 40);
  2495 
  2496 * Pure: disallow duplicate fact bindings within new-style theory files
  2497 (batch-mode only);
  2498 
  2499 * Provers: improved induct method: assumptions introduced by case
  2500 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2501 the goal statement); "foo" still refers to all facts collectively;
  2502 
  2503 * Provers: the function blast.overloaded has been removed: all constants
  2504 are regarded as potentially overloaded, which improves robustness in exchange
  2505 for slight decrease in efficiency;
  2506 
  2507 * Provers/linorder: New generic prover for transitivity reasoning over
  2508 linear orders.  Note: this prover is not efficient!
  2509 
  2510 * Isar: preview of problems to finish 'show' now produce an error
  2511 rather than just a warning (in interactive mode);
  2512 
  2513 
  2514 *** HOL ***
  2515 
  2516 * arith(_tac)
  2517 
  2518  - Produces a counter example if it cannot prove a goal.
  2519    Note that the counter example may be spurious if the goal is not a formula
  2520    of quantifier-free linear arithmetic.
  2521    In ProofGeneral the counter example appears in the trace buffer.
  2522 
  2523  - Knows about div k and mod k where k is a numeral of type nat or int.
  2524 
  2525  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2526    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2527    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2528 
  2529 * simp's arithmetic capabilities have been enhanced a bit: it now
  2530 takes ~= in premises into account (by performing a case split);
  2531 
  2532 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2533 are distributed over a sum of terms;
  2534 
  2535 * New tactic "trans_tac" and method "trans" instantiate
  2536 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2537 "<=", "<" and "=").
  2538 
  2539 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2540 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2541 
  2542 * 'typedef' command has new option "open" to suppress the set
  2543 definition;
  2544 
  2545 * functions Min and Max on finite sets have been introduced (theory
  2546 Finite_Set);
  2547 
  2548 * attribute [symmetric] now works for relations as well; it turns
  2549 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2550 
  2551 * induct over a !!-quantified statement (say !!x1..xn):
  2552   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2553 
  2554 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2555 %x. None. Warning: empty_def now refers to the previously hidden definition
  2556 of the empty set.
  2557 
  2558 * Algebra: formalization of classical algebra.  Intended as base for
  2559 any algebraic development in Isabelle.  Currently covers group theory
  2560 (up to Sylow's theorem) and ring theory (Universal Property of
  2561 Univariate Polynomials).  Contributions welcome;
  2562 
  2563 * GroupTheory: deleted, since its material has been moved to Algebra;
  2564 
  2565 * Complex: new directory of the complex numbers with numeric constants,
  2566 nonstandard complex numbers, and some complex analysis, standard and
  2567 nonstandard (Jacques Fleuriot);
  2568 
  2569 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2570 
  2571 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2572 Fleuriot);
  2573 
  2574 * Real/HahnBanach: updated and adapted to locales;
  2575 
  2576 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2577 Gray and Kramer);
  2578 
  2579 * UNITY: added the Meier-Sanders theory of progress sets;
  2580 
  2581 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2582 as abstract algorithms, instantiated to the JVM;
  2583 
  2584 * Bali: Java source language formalization. Type system, operational
  2585 semantics, axiomatic semantics. Supported language features:
  2586 classes, interfaces, objects,virtual methods, static methods,
  2587 static/instance fields, arrays, access modifiers, definite
  2588 assignment, exceptions.
  2589 
  2590 
  2591 *** ZF ***
  2592 
  2593 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2594 universe, etc.);
  2595 
  2596 * Main ZF: virtually all theories converted to new-style format;
  2597 
  2598 
  2599 *** ML ***
  2600 
  2601 * Pure: Tactic.prove provides sane interface for internal proofs;
  2602 omits the infamous "standard" operation, so this is more appropriate
  2603 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2604 
  2605 * Pure: improved error reporting of simprocs;
  2606 
  2607 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2608 up simprocs;
  2609 
  2610 
  2611 *** Document preparation ***
  2612 
  2613 * uses \par instead of \\ for line breaks in theory text. This may
  2614 shift some page breaks in large documents. To get the old behaviour
  2615 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2616 
  2617 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2618 other packages
  2619 
  2620 * \<euro> now needs package babel/greek instead of marvosym (which
  2621 broke \Rightarrow)
  2622 
  2623 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2624 textcomp package)
  2625 
  2626 
  2627 
  2628 New in Isabelle2002 (March 2002)
  2629 --------------------------------
  2630 
  2631 *** Document preparation ***
  2632 
  2633 * greatly simplified document preparation setup, including more
  2634 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2635 instructive isatool mkdir; users should basically be able to get
  2636 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2637 users may run a separate document processing stage manually like this:
  2638 "isatool usedir -D output HOL Test && isatool document Test/output";
  2639 
  2640 * theory dependency graph may now be incorporated into documents;
  2641 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2642 with \includegraphics of LaTeX;
  2643 
  2644 * proper spacing of consecutive markup elements, especially text
  2645 blocks after section headings;
  2646 
  2647 * support bold style (for single symbols only), input syntax is like
  2648 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2649 
  2650 * \<bullet> is now output as bold \cdot by default, which looks much
  2651 better in printed text;
  2652 
  2653 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2654 note that these symbols are currently unavailable in Proof General /
  2655 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2656 
  2657 * isatool latex no longer depends on changed TEXINPUTS, instead
  2658 isatool document copies the Isabelle style files to the target
  2659 location;
  2660 
  2661 
  2662 *** Isar ***
  2663 
  2664 * Pure/Provers: improved proof by cases and induction;
  2665   - 'case' command admits impromptu naming of parameters (such as
  2666     "case (Suc n)");
  2667   - 'induct' method divinates rule instantiation from the inductive
  2668     claim; no longer requires excessive ?P bindings for proper
  2669     instantiation of cases;
  2670   - 'induct' method properly enumerates all possibilities of set/type
  2671     rules; as a consequence facts may be also passed through *type*
  2672     rules without further ado;
  2673   - 'induct' method now derives symbolic cases from the *rulified*
  2674     rule (before it used to rulify cases stemming from the internal
  2675     atomized version); this means that the context of a non-atomic
  2676     statement becomes is included in the hypothesis, avoiding the
  2677     slightly cumbersome show "PROP ?case" form;
  2678   - 'induct' may now use elim-style induction rules without chaining
  2679     facts, using ``missing'' premises from the goal state; this allows
  2680     rules stemming from inductive sets to be applied in unstructured
  2681     scripts, while still benefitting from proper handling of non-atomic
  2682     statements; NB: major inductive premises need to be put first, all
  2683     the rest of the goal is passed through the induction;
  2684   - 'induct' proper support for mutual induction involving non-atomic
  2685     rule statements (uses the new concept of simultaneous goals, see
  2686     below);
  2687   - append all possible rule selections, but only use the first
  2688     success (no backtracking);
  2689   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2690   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2691   - added 'print_induct_rules' (covered by help item in recent Proof
  2692     General versions);
  2693   - moved induct/cases attributes to Pure, methods to Provers;
  2694   - generic method setup instantiated for FOL and HOL;
  2695 
  2696 * Pure: support multiple simultaneous goal statements, for example
  2697 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2698 meta-level mechanism, this acts as if several individual goals had
  2699 been stated separately; in particular common proof methods need to be
  2700 repeated in order to cover all claims; note that a single elimination
  2701 step is *not* sufficient to establish the two conjunctions, so this
  2702 fails:
  2703 
  2704   assume "A & B" then have A and B ..   (*".." fails*)
  2705 
  2706 better use "obtain" in situations as above; alternative refer to
  2707 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2708 
  2709 * Pure: proper integration with ``locales''; unlike the original
  2710 version by Florian Kammller, Isar locales package high-level proof
  2711 contexts rather than raw logical ones (e.g. we admit to include
  2712 attributes everywhere); operations on locales include merge and
  2713 rename; support for implicit arguments (``structures''); simultaneous
  2714 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2715 some examples;
  2716 
  2717 * Pure: the following commands have been ``localized'', supporting a
  2718 target locale specification "(in name)": 'lemma', 'theorem',
  2719 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2720 stored both within the locale and at the theory level (exported and
  2721 qualified by the locale name);
  2722 
  2723 * Pure: theory goals may now be specified in ``long'' form, with
  2724 ad-hoc contexts consisting of arbitrary locale elements. for example
  2725 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2726 definitions may be given, too); the result is a meta-level rule with
  2727 the context elements being discharged in the obvious way;
  2728 
  2729 * Pure: new proof command 'using' allows to augment currently used
  2730 facts after a goal statement ('using' is syntactically analogous to
  2731 'apply', but acts on the goal's facts only); this allows chained facts
  2732 to be separated into parts given before and after a claim, as in
  2733 ``from a and b have C using d and e <proof>'';
  2734 
  2735 * Pure: renamed "antecedent" case to "rule_context";
  2736 
  2737 * Pure: new 'judgment' command records explicit information about the
  2738 object-logic embedding (used by several tools internally); no longer
  2739 use hard-wired "Trueprop";
  2740 
  2741 * Pure: added 'corollary' command;
  2742 
  2743 * Pure: fixed 'token_translation' command;
  2744 
  2745 * Pure: removed obsolete 'exported' attribute;
  2746 
  2747 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2748 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2749 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2750 
  2751 * Pure: method 'atomize' presents local goal premises as object-level
  2752 statements (atomic meta-level propositions); setup controlled via
  2753 rewrite rules declarations of 'atomize' attribute; example
  2754 application: 'induct' method with proper rule statements in improper
  2755 proof *scripts*;
  2756 
  2757 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2758 now consider the syntactic context of assumptions, giving a better
  2759 chance to get type-inference of the arguments right (this is
  2760 especially important for locales);
  2761 
  2762 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2763 mode;
  2764 
  2765 * Pure/obtain: the formal conclusion "thesis", being marked as
  2766 ``internal'', may no longer be reference directly in the text;
  2767 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2768 situations;
  2769 
  2770 * Pure: generic 'sym' attribute which declares a rule both as pure
  2771 'elim?' and for the 'symmetric' operation;
  2772 
  2773 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2774 text; the fixed correlation with particular command syntax has been
  2775 discontinued;
  2776 
  2777 * Pure: new method 'rules' is particularly well-suited for proof
  2778 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2779 but often produces more compact proof terms with less detours;
  2780 
  2781 * Pure/Provers/classical: simplified integration with pure rule
  2782 attributes and methods; the classical "intro?/elim?/dest?"
  2783 declarations coincide with the pure ones; the "rule" method no longer
  2784 includes classically swapped intros; "intro" and "elim" methods no
  2785 longer pick rules from the context; also got rid of ML declarations
  2786 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2787 INCOMPATIBILITY;
  2788 
  2789 * Provers/classical: attribute 'swapped' produces classical inversions
  2790 of introduction rules;
  2791 
  2792 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2793 rules instead of full simplifier context; 'iff' attribute handles
  2794 conditional rules;
  2795 
  2796 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2797 
  2798 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2799 "(permissive)" option to recover old behavior;
  2800 
  2801 * HOL: 'inductive' no longer features separate (collective) attributes
  2802 for 'intros' (was found too confusing);
  2803 
  2804 * HOL: properly declared induction rules less_induct and
  2805 wf_induct_rule;
  2806 
  2807 
  2808 *** HOL ***
  2809 
  2810 * HOL: moved over to sane numeral syntax; the new policy is as
  2811 follows:
  2812 
  2813   - 0 and 1 are polymorphic constants, which are defined on any
  2814   numeric type (nat, int, real etc.);
  2815 
  2816   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2817   binary representation internally;
  2818 
  2819   - type nat has special constructor Suc, and generally prefers Suc 0
  2820   over 1::nat and Suc (Suc 0) over 2::nat;
  2821 
  2822 This change may cause significant problems of INCOMPATIBILITY; here
  2823 are some hints on converting existing sources:
  2824 
  2825   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2826   entities, so expressions involving "-" (unary or binary minus) need
  2827   to be spaced properly;
  2828 
  2829   - existing occurrences of "1" may need to be constraint "1::nat" or
  2830   even replaced by Suc 0; similar for old "2";
  2831 
  2832   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2833 
  2834   - remove all special provisions on numerals in proofs;
  2835 
  2836 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2837 representation (depends on bin_arith_simps in the default context);
  2838 
  2839 * HOL: symbolic syntax for x^2 (numeral 2);
  2840 
  2841 * HOL: the class of all HOL types is now called "type" rather than
  2842 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2843 in axclass/classes, instance/arities, and (usually rare) occurrences
  2844 in typings (of consts etc.); internally the class is called
  2845 "HOL.type", ML programs should refer to HOLogic.typeS;
  2846 
  2847 * HOL/record package improvements:
  2848   - new derived operations "fields" to build a partial record section,
  2849     "extend" to promote a fixed record to a record scheme, and
  2850     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2851     declared as simp by default;
  2852   - shared operations ("more", "fields", etc.) now need to be always
  2853     qualified) --- potential INCOMPATIBILITY;
  2854   - removed "make_scheme" operations (use "make" with "extend") --
  2855     INCOMPATIBILITY;
  2856   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2857   - provides cases/induct rules for use with corresponding Isar
  2858     methods (for concrete records, record schemes, concrete more
  2859     parts, and schematic more parts -- in that order);
  2860   - internal definitions directly based on a light-weight abstract
  2861     theory of product types over typedef rather than datatype;
  2862 
  2863 * HOL: generic code generator for generating executable ML code from
  2864 specifications; specific support for HOL constructs such as inductive
  2865 datatypes and sets, as well as recursive functions; can be invoked
  2866 via 'generate_code' theory section;
  2867 
  2868 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2869 
  2870 * HOL: consolidated and renamed several theories.  In particular:
  2871         Ord.thy has been absorbed into HOL.thy
  2872         String.thy has been absorbed into List.thy
  2873 
  2874 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2875 (beware of argument permutation!);
  2876 
  2877 * HOL: linorder_less_split superseded by linorder_cases;
  2878 
  2879 * HOL/List: "nodups" renamed to "distinct";
  2880 
  2881 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2882 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2883   - Ex_def has changed, now need to use some_eq_ex
  2884 
  2885 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2886 in this (rare) case use:
  2887 
  2888   delSWrapper "split_all_tac"
  2889   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2890 
  2891 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2892 MAY FAIL;
  2893 
  2894 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2895 Isabelle's type classes, ^ on functions and relations has too general
  2896 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2897 necessary to attach explicit type constraints;
  2898 
  2899 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2900 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2901 renamed accordingly (eg "compI" -> "rel_compI").
  2902 
  2903 * HOL: syntax translations now work properly with numerals and records
  2904 expressions;
  2905 
  2906 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2907 of "lam" -- INCOMPATIBILITY;
  2908 
  2909 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2910 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2911 renamed "Product_Type.unit";
  2912 
  2913 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2914 
  2915 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2916 the "cases" method);
  2917 
  2918 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2919 Florian Kammller);
  2920 
  2921 * HOL/IMP: updated and converted to new-style theory format; several
  2922 parts turned into readable document, with proper Isar proof texts and
  2923 some explanations (by Gerwin Klein);
  2924 
  2925 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2926 
  2927 * HOL-Hyperreal is now a logic image;
  2928 
  2929 
  2930 *** HOLCF ***
  2931 
  2932 * Isar: consts/constdefs supports mixfix syntax for continuous
  2933 operations;
  2934 
  2935 * Isar: domain package adapted to new-style theory format, e.g. see
  2936 HOLCF/ex/Dnat.thy;
  2937 
  2938 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2939 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2940 lift.induct_tac, always use UU instead of Undef;
  2941 
  2942 * HOLCF/IMP: updated and converted to new-style theory;
  2943 
  2944 
  2945 *** ZF ***
  2946 
  2947 * Isar: proper integration of logic-specific tools and packages,
  2948 including theory commands '(co)inductive', '(co)datatype',
  2949 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2950 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2951 
  2952 * theory Main no longer includes AC; for the Axiom of Choice, base
  2953 your theory on Main_ZFC;
  2954 
  2955 * the integer library now covers quotients and remainders, with many
  2956 laws relating division to addition, multiplication, etc.;
  2957 
  2958 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2959 typeless version of the formalism;
  2960 
  2961 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2962 format;
  2963 
  2964 * ZF/Induct: new directory for examples of inductive definitions,
  2965 including theory Multiset for multiset orderings; converted to
  2966 new-style theory format;
  2967 
  2968 * ZF: many new theorems about lists, ordinals, etc.;
  2969 
  2970 
  2971 *** General ***
  2972 
  2973 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2974 variable proof controls level of detail: 0 = no proofs (only oracle
  2975 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2976 also ref manual for further ML interfaces;
  2977 
  2978 * Pure/axclass: removed obsolete ML interface
  2979 goal_subclass/goal_arity;
  2980 
  2981 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2982 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2983 separate tokens, so expressions involving minus need to be spaced
  2984 properly;
  2985 
  2986 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2987 rather than "infixl" or "infixr";
  2988 
  2989 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2990 sort constraint specifications in type inference; e.g. "x::_::foo"
  2991 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2992 type variable);
  2993 
  2994 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2995 control output of nested => (types); the default behavior is
  2996 "type_brackets";
  2997 
  2998 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2999 tokens into AST constants;
  3000 
  3001 * Pure/syntax: prefer later declarations of translations and print
  3002 translation functions; potential INCOMPATIBILITY: need to reverse
  3003 multiple declarations for same syntax element constant;
  3004 
  3005 * Pure/show_hyps reset by default (in accordance to existing Isar
  3006 practice);
  3007 
  3008 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3009 addSafter;
  3010 
  3011 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3012 as well;
  3013 
  3014 * system: tested support for MacOS X; should be able to get Isabelle +
  3015 Proof General to work in a plain Terminal after installing Poly/ML
  3016 (e.g. from the Isabelle distribution area) and GNU bash alone
  3017 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3018 support requires further installations, e.g. from
  3019 http://fink.sourceforge.net/);
  3020 
  3021 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3022 
  3023 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3024 of 40 MB), cf. ML_OPTIONS;
  3025 
  3026 * system: Proof General keywords specification is now part of the
  3027 Isabelle distribution (see etc/isar-keywords.el);
  3028 
  3029 * system: support for persistent Proof General sessions (refrain from
  3030 outdating all loaded theories on startup); user may create writable
  3031 logic images like this: ``isabelle -q HOL Test'';
  3032 
  3033 * system: smart selection of Isabelle process versus Isabelle
  3034 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3035 run both "isabelle" and "Isabelle" even if file names are badly
  3036 damaged (executable inspects the case of the first letter of its own
  3037 name); added separate "isabelle-process" and "isabelle-interface";
  3038 
  3039 * system: refrain from any attempt at filtering input streams; no
  3040 longer support ``8bit'' encoding of old isabelle font, instead proper
  3041 iso-latin characters may now be used; the related isatools
  3042 "symbolinput" and "nonascii" have disappeared as well;
  3043 
  3044 * system: removed old "xterm" interface (the print modes "xterm" and
  3045 "xterm_color" are still available for direct use in a suitable
  3046 terminal);
  3047 
  3048 
  3049 
  3050 New in Isabelle99-2 (February 2001)
  3051 -----------------------------------
  3052 
  3053 *** Overview of INCOMPATIBILITIES ***
  3054 
  3055 * HOL: please note that theories in the Library and elsewhere often use the
  3056 new-style (Isar) format; to refer to their theorems in an ML script you must
  3057 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3058 
  3059 * HOL: inductive package no longer splits induction rule aggressively,
  3060 but only as far as specified by the introductions given; the old
  3061 format may be recovered via ML function complete_split_rule or attribute
  3062 'split_rule (complete)';
  3063 
  3064 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3065 gfp_Tarski to gfp_unfold;
  3066 
  3067 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3068 
  3069 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3070 relation); infix "^^" has been renamed "``"; infix "``" has been
  3071 renamed "`"; "univalent" has been renamed "single_valued";
  3072 
  3073 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3074 operation;
  3075 
  3076 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3077 
  3078 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3079 
  3080 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3081 consequence, it is no longer monotonic wrt. the local goal context
  3082 (which is now passed through the inductive cases);
  3083 
  3084 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3085 \<gg> to \<ggreater>;
  3086 
  3087 
  3088 *** Document preparation ***
  3089 
  3090 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3091 available: are "it" for near math-mode best-style output, "sl" for
  3092 slanted text style, and "tt" for plain type-writer; if no
  3093 \isabellestyle command is given, output is according to slanted
  3094 type-writer);
  3095 
  3096 * support sub/super scripts (for single symbols only), input syntax is
  3097 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3098 
  3099 * some more standard symbols; see Appendix A of the system manual for
  3100 the complete list of symbols defined in isabellesym.sty;
  3101 
  3102 * improved isabelle style files; more abstract symbol implementation
  3103 (should now use \isamath{...} and \isatext{...} in custom symbol
  3104 definitions);
  3105 
  3106 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3107 state; Note that presentation of goal states does not conform to
  3108 actual human-readable proof documents.  Please do not include goal
  3109 states into document output unless you really know what you are doing!
  3110 
  3111 * proper indentation of antiquoted output with proportional LaTeX
  3112 fonts;
  3113 
  3114 * no_document ML operator temporarily disables LaTeX document
  3115 generation;
  3116 
  3117 * isatool unsymbolize tunes sources for plain ASCII communication;
  3118 
  3119 
  3120 *** Isar ***
  3121 
  3122 * Pure: Isar now suffers initial goal statements to contain unbound
  3123 schematic variables (this does not conform to actual readable proof
  3124 documents, due to unpredictable outcome and non-compositional proof
  3125 checking); users who know what they are doing may use schematic goals
  3126 for Prolog-style synthesis of proven results;
  3127 
  3128 * Pure: assumption method (an implicit finishing) now handles actual
  3129 rules as well;
  3130 
  3131 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3132 initial goal, declare "that" only as Pure intro (only for single
  3133 steps); the "that" rule assumption may now be involved in implicit
  3134 finishing, thus ".." becomes a feasible for trivial obtains;
  3135 
  3136 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3137 instance proofs may be performed by "..";
  3138 
  3139 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3140 statements as well;
  3141 
  3142 * Pure: more robust selection of calculational rules;
  3143 
  3144 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3145 rule (as well as the assumption rule);
  3146 
  3147 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3148 lemmas, using the graph browser tool;
  3149 
  3150 * Pure: predict failure of "show" in interactive mode;
  3151 
  3152 * Pure: 'thms_containing' now takes actual terms as arguments;
  3153 
  3154 * HOL: improved method 'induct' --- now handles non-atomic goals
  3155 (potential INCOMPATIBILITY); tuned error handling;
  3156 
  3157 * HOL: cases and induct rules now provide explicit hints about the
  3158 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3159 any remaining facts are inserted into the goal verbatim;
  3160 
  3161 * HOL: local contexts (aka cases) may now contain term bindings as
  3162 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3163 the result to be shown in each case;
  3164 
  3165 * HOL: added 'recdef_tc' command;
  3166 
  3167 * isatool convert assists in eliminating legacy ML scripts;
  3168 
  3169 
  3170 *** HOL ***
  3171 
  3172 * HOL/Library: a collection of generic theories to be used together
  3173 with main HOL; the theory loader path already includes this directory
  3174 by default; the following existing theories have been moved here:
  3175 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3176 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3177 
  3178 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3179 modelling and verification task performed in Isabelle/HOL +
  3180 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3181 
  3182 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3183 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3184 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3185 'domain', this makes the theory consistent with mathematical
  3186 literature;
  3187 
  3188 * HOL basics: added overloaded operations "inverse" and "divide"
  3189 (infix "/"), syntax for generic "abs" operation, generic summation
  3190 operator \<Sum>;
  3191 
  3192 * HOL/typedef: simplified package, provide more useful rules (see also
  3193 HOL/subset.thy);
  3194 
  3195 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3196 now expressed as a proper nested rule (old-style tactic scripts may
  3197 require atomize_strip_tac to cope with non-atomic premises);
  3198 
  3199 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3200 to "split_conv" (old name still available for compatibility);
  3201 
  3202 * HOL: improved concrete syntax for strings (e.g. allows translation
  3203 rules with string literals);
  3204 
  3205 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3206  and Fleuriot's mechanization of analysis, including the transcendental
  3207  functions for the reals;
  3208 
  3209 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3210 
  3211 
  3212 *** CTT ***
  3213 
  3214 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3215 "lam" is displayed as TWO lambda-symbols
  3216 
  3217 * CTT: theory Main now available, containing everything (that is, Bool
  3218 and Arith);
  3219 
  3220 
  3221 *** General ***
  3222 
  3223 * Pure: the Simplifier has been implemented properly as a derived rule
  3224 outside of the actual kernel (at last!); the overall performance
  3225 penalty in practical applications is about 50%, while reliability of
  3226 the Isabelle inference kernel has been greatly improved;
  3227 
  3228 * print modes "brackets" and "no_brackets" control output of nested =>
  3229 (types) and ==> (props); the default behaviour is "brackets";
  3230 
  3231 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3232 as assumptions as well;
  3233 
  3234 * system: support Poly/ML 4.0;
  3235 
  3236 * system: isatool install handles KDE version 1 or 2;
  3237 
  3238 
  3239 
  3240 New in Isabelle99-1 (October 2000)
  3241 ----------------------------------
  3242 
  3243 *** Overview of INCOMPATIBILITIES ***
  3244 
  3245 * HOL: simplification of natural numbers is much changed; to partly
  3246 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3247 issue the following ML commands:
  3248 
  3249   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3250   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3251 
  3252 * HOL: simplification no longer dives into case-expressions; this is
  3253 controlled by "t.weak_case_cong" for each datatype t;
  3254 
  3255 * HOL: nat_less_induct renamed to less_induct;
  3256 
  3257 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3258 fixsome to patch .thy and .ML sources automatically;
  3259 
  3260   select_equality  -> some_equality
  3261   select_eq_Ex     -> some_eq_ex
  3262   selectI2EX       -> someI2_ex
  3263   selectI2         -> someI2
  3264   selectI          -> someI
  3265   select1_equality -> some1_equality
  3266   Eps_sym_eq       -> some_sym_eq_trivial
  3267   Eps_eq           -> some_eq_trivial
  3268 
  3269 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3270 
  3271 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3272 instead);
  3273 
  3274 * HOL: the recursion equations generated by 'recdef' are now called
  3275 f.simps instead of f.rules;
  3276 
  3277 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3278 
  3279 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3280 sometimes be needed;
  3281 
  3282 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3283 
  3284 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3285 
  3286 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3287 product is now "<*>" instead of "Times"; the lexicographic product is
  3288 now "<*lex*>" instead of "**";
  3289 
  3290 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3291 of main HOL, but was unused); better use HOL's datatype package;
  3292 
  3293 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3294 the old syntax may be recovered as follows:
  3295 
  3296   syntax (symbols)
  3297     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3298       (infixl "\\<oplus>" 100)
  3299 
  3300 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3301 
  3302 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3303 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3304 internally;
  3305 
  3306 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3307 changed from A/r to A//r;
  3308 
  3309 * ZF: new treatment of arithmetic (nat & int) may break some old
  3310 proofs;
  3311 
  3312 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3313 rulify -> rule_format, elimify -> elim_format, ...);
  3314 
  3315 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3316 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3317 should have to change intro!! to intro? only); replaced "delrule" by
  3318 "rule del";
  3319 
  3320 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3321 
  3322 * Provers: strengthened force_tac by using new first_best_tac;
  3323 
  3324 * LaTeX document preparation: several changes of isabelle.sty (see
  3325 lib/texinputs);
  3326 
  3327 
  3328 *** Document preparation ***
  3329 
  3330 * formal comments (text blocks etc.) in new-style theories may now
  3331 contain antiquotations of thm/prop/term/typ/text to be presented
  3332 according to latex print mode; concrete syntax is like this:
  3333 @{term[show_types] "f(x) = a + x"};
  3334 
  3335 * isatool mkdir provides easy setup of Isabelle session directories,
  3336 including proper document sources;
  3337 
  3338 * generated LaTeX sources are now deleted after successful run
  3339 (isatool document -c); may retain a copy somewhere else via -D option
  3340 of isatool usedir;
  3341 
  3342 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3343 style files, achieving self-contained LaTeX sources and simplifying
  3344 LaTeX debugging;
  3345 
  3346 * old-style theories now produce (crude) LaTeX output as well;
  3347 
  3348 * browser info session directories are now self-contained (may be put
  3349 on WWW server seperately); improved graphs of nested sessions; removed
  3350 graph for 'all sessions';
  3351 
  3352 * several improvements in isabelle style files; \isabellestyle{it}
  3353 produces fake math mode output; \isamarkupheader is now \section by
  3354 default; see lib/texinputs/isabelle.sty etc.;
  3355 
  3356 
  3357 *** Isar ***
  3358 
  3359 * Isar/Pure: local results and corresponding term bindings are now
  3360 subject to Hindley-Milner polymorphism (similar to ML); this
  3361 accommodates incremental type-inference very nicely;
  3362 
  3363 * Isar/Pure: new derived language element 'obtain' supports
  3364 generalized existence reasoning;
  3365 
  3366 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3367 support accumulation of results, without applying any rules yet;
  3368 useful to collect intermediate results without explicit name
  3369 references, and for use with transitivity rules with more than 2
  3370 premises;
  3371 
  3372 * Isar/Pure: scalable support for case-analysis type proofs: new
  3373 'case' language element refers to local contexts symbolically, as
  3374 produced by certain proof methods; internally, case names are attached
  3375 to theorems as "tags";
  3376 
  3377 * Isar/Pure: theory command 'hide' removes declarations from
  3378 class/type/const name spaces;
  3379 
  3380 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3381 indicate potential overloading;
  3382 
  3383 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3384 
  3385 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3386 "{a,b,c}" instead of {a,b,c};
  3387 
  3388 * Isar/Pure now provides its own version of intro/elim/dest
  3389 attributes; useful for building new logics, but beware of confusion
  3390 with the version in Provers/classical;
  3391 
  3392 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3393 case name 'antecedent';
  3394 
  3395 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3396 to the current context is now done automatically);
  3397 
  3398 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3399 for definining proof methods in ML;
  3400 
  3401 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3402 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3403 most cases, one should have to change intro!! to intro? only);
  3404 replaced "delrule" by "rule del";
  3405 
  3406 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3407 'symmetric' attribute (the latter supercedes [RS sym]);
  3408 
  3409 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3410 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3411 well (including splits);
  3412 
  3413 * Isar/Provers: Simplifier and Classical methods now support all kind
  3414 of modifiers used in the past, including 'cong', 'iff', etc.
  3415 
  3416 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3417 of Simplifier and Classical reasoner);
  3418 
  3419 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3420 now support named cases; major packages (inductive, datatype, primrec,
  3421 recdef) support case names and properly name parameters;
  3422 
  3423 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3424 monotonicity conditions are extracted to be proven at end of
  3425 calculations;
  3426 
  3427 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3428 method anyway;
  3429 
  3430 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3431 split_if split_if_asm; datatype package provides theorems foo.splits =
  3432 foo.split foo.split_asm for each datatype;
  3433 
  3434 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3435 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3436 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3437 use "(cases (simplified))" method in proper proof texts);
  3438 
  3439 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3440 
  3441 * Isar: names of theorems etc. may be natural numbers as well;
  3442 
  3443 * Isar: 'pr' command: optional arguments for goals_limit and
  3444 ProofContext.prems_limit; no longer prints theory contexts, but only
  3445 proof states;
  3446 
  3447 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3448 additional print modes to be specified; e.g. "pr(latex)" will print
  3449 proof state according to the Isabelle LaTeX style;
  3450 
  3451 * Isar: improved support for emulating tactic scripts, including proof
  3452 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3453 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3454 (for HOL datatypes);
  3455 
  3456 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3457 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3458 'proof method scripts' have to be in depth-first order;
  3459 
  3460 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3461 
  3462 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3463 should instead use individual commands for printing items
  3464 (print_commands, print_methods etc.);
  3465 
  3466 * Isar: added 'nothing' --- the empty list of theorems;
  3467 
  3468 
  3469 *** HOL ***
  3470 
  3471 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3472 corresponding virtual machine and a specification of its bytecode
  3473 verifier and a lightweight bytecode verifier, including proofs of
  3474 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3475 Cornelia Pusch (see also the homepage of project Bali at
  3476 http://isabelle.in.tum.de/Bali/);
  3477 
  3478 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3479 Clemens Ballarin;
  3480 
  3481 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3482 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3483 Rasmussen;
  3484 
  3485 * HOL/Lattice: fundamental concepts of lattice theory and order
  3486 structures, including duals, properties of bounds versus algebraic
  3487 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3488 Theorem for complete lattices etc.; may also serve as a demonstration
  3489 for abstract algebraic reasoning using axiomatic type classes, and
  3490 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3491 
  3492 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3493 von Oheimb;
  3494 
  3495 * HOL/IMPP: extension of IMP with local variables and mutually
  3496 recursive procedures, by David von Oheimb;
  3497 
  3498 * HOL/Lambda: converted into new-style theory and document;
  3499 
  3500 * HOL/ex/Multiquote: example of multiple nested quotations and
  3501 anti-quotations -- basically a generalized version of de-Bruijn
  3502 representation; very useful in avoiding lifting of operations;
  3503 
  3504 * HOL/record: added general record equality rule to simpset; fixed
  3505 select-update simplification procedure to handle extended records as
  3506 well; admit "r" as field name;
  3507 
  3508 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3509 other numeric types and also as the identity of groups, rings, etc.;
  3510 
  3511 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3512 Types nat and int belong to this axclass;
  3513 
  3514 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3515    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3516    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3517   two terms #m*u and #n*u are replaced by #(m+n)*u
  3518     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3519   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3520     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3521 
  3522 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3523 powerful prover for predicate logic but knows nothing of clasets; see
  3524 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3525 
  3526 * HOL: new version of "case_tac" subsumes both boolean case split and
  3527 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3528 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3529 
  3530 * HOL: simplification no longer dives into case-expressions: only the
  3531 selector expression is simplified, but not the remaining arms; to
  3532 enable full simplification of case-expressions for datatype t, you may
  3533 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3534 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3535 
  3536 * HOL/recdef: the recursion equations generated by 'recdef' for
  3537 function 'f' are now called f.simps instead of f.rules; if all
  3538 termination conditions are proved automatically, these simplification
  3539 rules are added to the simpset, as in primrec; rules may be named
  3540 individually as well, resulting in a separate list of theorems for
  3541 each equation;
  3542 
  3543 * HOL/While is a new theory that provides a while-combinator. It
  3544 permits the definition of tail-recursive functions without the
  3545 provision of a termination measure. The latter is necessary once the
  3546 invariant proof rule for while is applied.
  3547 
  3548 * HOL: new (overloaded) notation for the set of elements below/above
  3549 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3550 
  3551 * HOL: theorems impI, allI, ballI bound as "strip";
  3552 
  3553 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3554 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3555 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3556 
  3557 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3558 
  3559 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3560 main HOL, but was unused);
  3561 
  3562 * HOL: fewer consts declared as global (e.g. have to refer to
  3563 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3564 
  3565 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3566 in case of overlap with user translations (e.g. judgements over
  3567 tuples); (note that the underlying logical represenation is still
  3568 bogus);
  3569 
  3570 
  3571 *** ZF ***
  3572 
  3573 * ZF: simplification automatically cancels common terms in arithmetic
  3574 expressions over nat and int;
  3575 
  3576 * ZF: new treatment of nat to minimize type-checking: all operators
  3577 coerce their operands to a natural number using the function natify,
  3578 making the algebraic laws unconditional;
  3579 
  3580 * ZF: as above, for int: operators coerce their operands to an integer
  3581 using the function intify;
  3582 
  3583 * ZF: the integer library now contains many of the usual laws for the
  3584 orderings, including $<=, and monotonicity laws for $+ and $*;
  3585 
  3586 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3587 simplification;
  3588 
  3589 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3590 to the simplifier and classical reasoner simultaneously;
  3591 
  3592 
  3593 *** General ***
  3594 
  3595 * Provers: blast_tac now handles actual object-logic rules as
  3596 assumptions; note that auto_tac uses blast_tac internally as well;
  3597 
  3598 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3599 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3600 
  3601 * Provers: delrules now handles destruct rules as well (no longer need
  3602 explicit make_elim);
  3603 
  3604 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3605   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3606 use instead the strong form,
  3607   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3608 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3609 from destruct-rules;
  3610 
  3611 * Provers: Simplifier.easy_setup provides a fast path to basic
  3612 Simplifier setup for new object-logics;
  3613 
  3614 * Pure: AST translation rules no longer require constant head on LHS;
  3615 
  3616 * Pure: improved name spaces: ambiguous output is qualified; support
  3617 for hiding of names;
  3618 
  3619 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3620 XSYMBOL_HOME; no longer need to do manual configuration in most
  3621 situations;
  3622 
  3623 * system: compression of ML heaps images may now be controlled via -c
  3624 option of isabelle and isatool usedir (currently only observed by
  3625 Poly/ML);
  3626 
  3627 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3628 useful for remote X11);
  3629 
  3630 * system: provide TAGS file for Isabelle sources;
  3631 
  3632 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3633 order;
  3634 
  3635 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3636 timing flag supersedes proof_timing and Toplevel.trace;
  3637 
  3638 * ML: new combinators |>> and |>>> for incremental transformations
  3639 with secondary results (e.g. certain theory extensions):
  3640 
  3641 * ML: PureThy.add_defs gets additional argument to indicate potential
  3642 overloading (usually false);
  3643 
  3644 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3645 results;
  3646 
  3647 
  3648 
  3649 New in Isabelle99 (October 1999)
  3650 --------------------------------
  3651 
  3652 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3653 
  3654 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3655 are no longer simplified.  (This allows the simplifier to unfold recursive
  3656 functional programs.)  To restore the old behaviour, declare
  3657 
  3658     Delcongs [if_weak_cong];
  3659 
  3660 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3661 complement;
  3662 
  3663 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3664 
  3665 * HOL/datatype: mutual_induct_tac no longer exists --
  3666   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3667 
  3668 * HOL/typedef: fixed type inference for representing set; type
  3669 arguments now have to occur explicitly on the rhs as type constraints;
  3670 
  3671 * ZF: The con_defs part of an inductive definition may no longer refer
  3672 to constants declared in the same theory;
  3673 
  3674 * HOL, ZF: the function mk_cases, generated by the inductive
  3675 definition package, has lost an argument.  To simplify its result, it
  3676 uses the default simpset instead of a supplied list of theorems.
  3677 
  3678 * HOL/List: the constructors of type list are now Nil and Cons;
  3679 
  3680 * Simplifier: the type of the infix ML functions
  3681         setSSolver addSSolver setSolver addSolver
  3682 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3683 for packaging solvers. A solver is created via
  3684         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3685 where the string argument is only a comment.
  3686 
  3687 
  3688 *** Proof tools ***
  3689 
  3690 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3691 decision procedure for linear arithmetic. Currently it is used for
  3692 types `nat', `int', and `real' in HOL (see below); it can, should and
  3693 will be instantiated for other types and logics as well.
  3694 
  3695 * The simplifier now accepts rewrite rules with flexible heads, eg
  3696      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3697   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3698   matching.
  3699 
  3700 
  3701 *** General ***
  3702 
  3703 * New Isabelle/Isar subsystem provides an alternative to traditional
  3704 tactical theorem proving; together with the ProofGeneral/isar user
  3705 interface it offers an interactive environment for developing human
  3706 readable proof documents (Isar == Intelligible semi-automated
  3707 reasoning); for further information see isatool doc isar-ref,
  3708 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3709 
  3710 * improved and simplified presentation of theories: better HTML markup
  3711 (including colors), graph views in several sizes; isatool usedir now
  3712 provides a proper interface for user theories (via -P option); actual
  3713 document preparation based on (PDF)LaTeX is available as well (for
  3714 new-style theories only); see isatool doc system for more information;
  3715 
  3716 * native support for Proof General, both for classic Isabelle and
  3717 Isabelle/Isar;
  3718 
  3719 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3720 using the graph browser tool;
  3721 
  3722 * Isabelle manuals now also available as PDF;
  3723 
  3724 * theory loader rewritten from scratch (may not be fully
  3725 bug-compatible); old loadpath variable has been replaced by show_path,
  3726 add_path, del_path, reset_path functions; new operations such as
  3727 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3728 isatool doc ref);
  3729 
  3730 * improved isatool install: option -k creates KDE application icon,
  3731 option -p DIR installs standalone binaries;
  3732 
  3733 * added ML_PLATFORM setting (useful for cross-platform installations);
  3734 more robust handling of platform specific ML images for SML/NJ;
  3735 
  3736 * the settings environment is now statically scoped, i.e. it is never
  3737 created again in sub-processes invoked from isabelle, isatool, or
  3738 Isabelle;
  3739 
  3740 * path element specification '~~' refers to '$ISABELLE_HOME';
  3741 
  3742 * in locales, the "assumes" and "defines" parts may be omitted if
  3743 empty;
  3744 
  3745 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3746 long arrows);
  3747 
  3748 * new print_mode "HTML";
  3749 
  3750 * new flag show_tags controls display of tags of theorems (which are
  3751 basically just comments that may be attached by some tools);
  3752 
  3753 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3754 mode and goal output format:
  3755 
  3756 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3757 244c244
  3758 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3759 ---
  3760 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3761 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3762 181c181
  3763 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3764 ---
  3765 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3766 
  3767 * function bind_thms stores lists of theorems (cf. bind_thm);
  3768 
  3769 * new shorthand tactics ftac, eatac, datac, fatac;
  3770 
  3771 * qed (and friends) now accept "" as result name; in that case the
  3772 theorem is not stored, but proper checks and presentation of the
  3773 result still apply;
  3774 
  3775 * theorem database now also indexes constants "Trueprop", "all",
  3776 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3777 
  3778 
  3779 *** HOL ***
  3780 
  3781 ** HOL arithmetic **
  3782 
  3783 * There are now decision procedures for linear arithmetic over nat and
  3784 int:
  3785 
  3786 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3787 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3788 are treated as atomic; subformulae not involving type `nat' or `int'
  3789 are ignored; quantified subformulae are ignored unless they are
  3790 positive universal or negative existential. The tactic has to be
  3791 invoked by hand and can be a little bit slow. In particular, the
  3792 running time is exponential in the number of occurrences of `min' and
  3793 `max', and `-' on `nat'.
  3794 
  3795 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3796 (negated) (in)equalities among the premises and the conclusion into
  3797 account (i.e. no compound formulae) and does not know about `min' and
  3798 `max', and `-' on `nat'. It is fast and is used automatically by the
  3799 simplifier.
  3800 
  3801 NB: At the moment, these decision procedures do not cope with mixed
  3802 nat/int formulae where the two parts interact, such as `m < n ==>
  3803 int(m) < int(n)'.
  3804 
  3805 * HOL/Numeral provides a generic theory of numerals (encoded
  3806 efficiently as bit strings); setup for types nat/int/real is in place;
  3807 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3808 int, existing theories and proof scripts may require a few additional
  3809 type constraints;
  3810 
  3811 * integer division and remainder can now be performed on constant
  3812 arguments;
  3813 
  3814 * many properties of integer multiplication, division and remainder
  3815 are now available;
  3816 
  3817 * An interface to the Stanford Validity Checker (SVC) is available through the
  3818 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3819 are proved automatically.  SVC must be installed separately, and its results
  3820 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3821 invocation of the underlying oracle).  For SVC see
  3822   http://verify.stanford.edu/SVC
  3823 
  3824 * IsaMakefile: the HOL-Real target now builds an actual image;
  3825 
  3826 
  3827 ** HOL misc **
  3828 
  3829 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3830 (in Isabelle/Isar) -- by Gertrud Bauer;
  3831 
  3832 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3833 analysis for assembly languages with subtypes;
  3834 
  3835 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3836 -- avoids syntactic ambiguities and treats state, transition, and
  3837 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3838 changed syntax and (many) tactics;
  3839 
  3840 * HOL/inductive: Now also handles more general introduction rules such
  3841   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3842   theorems are now maintained within the theory (maintained via the
  3843   "mono" attribute);
  3844 
  3845 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3846   (using function types) such as
  3847 
  3848   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3849 
  3850 * HOL/record: record_simproc (part of the default simpset) takes care
  3851 of selectors applied to updated records; record_split_tac is no longer
  3852 part of the default claset; update_defs may now be removed from the
  3853 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3854 
  3855   claset_ref () := claset() addSWrapper record_split_wrapper;
  3856   Delsimprocs [record_simproc]
  3857 
  3858 * HOL/typedef: fixed type inference for representing set; type
  3859 arguments now have to occur explicitly on the rhs as type constraints;
  3860 
  3861 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3862 names rather than an ML expression;
  3863 
  3864 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3865 supplied later.  Program schemes can be defined, such as
  3866     "While B C s = (if B s then While B C (C s) else s)"
  3867 where the well-founded relation can be chosen after B and C have been given.
  3868 
  3869 * HOL/List: the constructors of type list are now Nil and Cons;
  3870 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3871 course, ML tools referring to List.list.op # etc. have to be adapted;
  3872 
  3873 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3874 disabled by default; run isabelle with option -m HOL to get back to
  3875 the original Gordon/HOL-style output;
  3876 
  3877 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3878 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3879 
  3880 * HOL basic syntax simplified (more orthogonal): all variants of
  3881 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3882 Eps operator is provided as well: "SOME x. P[x]";
  3883 
  3884 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3885 
  3886 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3887 thus available for user theories;
  3888 
  3889 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3890 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3891 time;
  3892 
  3893 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3894 several times and then mp;
  3895 
  3896 
  3897 *** LK ***
  3898 
  3899 * the notation <<...>> is now available as a notation for sequences of
  3900 formulas;
  3901 
  3902 * the simplifier is now installed
  3903 
  3904 * the axiom system has been generalized (thanks to Soren Heilmann)
  3905 
  3906 * the classical reasoner now has a default rule database
  3907 
  3908 
  3909 *** ZF ***
  3910 
  3911 * new primrec section allows primitive recursive functions to be given
  3912 directly (as in HOL) over datatypes and the natural numbers;
  3913 
  3914 * new tactics induct_tac and exhaust_tac for induction (or case
  3915 analysis) over datatypes and the natural numbers;
  3916 
  3917 * the datatype declaration of type T now defines the recursor T_rec;
  3918 
  3919 * simplification automatically does freeness reasoning for datatype
  3920 constructors;
  3921 
  3922 * automatic type-inference, with AddTCs command to insert new
  3923 type-checking rules;
  3924 
  3925 * datatype introduction rules are now added as Safe Introduction rules
  3926 to the claset;
  3927 
  3928 * the syntax "if P then x else y" is now available in addition to
  3929 if(P,x,y);
  3930 
  3931 
  3932 *** Internal programming interfaces ***
  3933 
  3934 * tuned simplifier trace output; new flag debug_simp;
  3935 
  3936 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3937 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3938 
  3939 * AxClass.axclass_tac lost the theory argument;
  3940 
  3941 * tuned current_goals_markers semantics: begin / end goal avoids
  3942 printing empty lines;
  3943 
  3944 * removed prs and prs_fn hook, which was broken because it did not
  3945 include \n in its semantics, forcing writeln to add one
  3946 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3947 string -> unit if you really want to output text without newline;
  3948 
  3949 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3950 plain output, interface builders may have to enable 'isabelle_font'
  3951 mode to get Isabelle font glyphs as before;
  3952 
  3953 * refined token_translation interface; INCOMPATIBILITY: output length
  3954 now of type real instead of int;
  3955 
  3956 * theory loader actions may be traced via new ThyInfo.add_hook
  3957 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3958 your own database of information attached to *whole* theories -- as
  3959 opposed to intra-theory data slots offered via TheoryDataFun;
  3960 
  3961 * proper handling of dangling sort hypotheses (at last!);
  3962 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3963 extra sort hypotheses that can be witnessed from the type signature;
  3964 the force_strip_shyps flag is gone, any remaining shyps are simply
  3965 left in the theorem (with a warning issued by strip_shyps_warning);
  3966 
  3967 
  3968 
  3969 New in Isabelle98-1 (October 1998)
  3970 ----------------------------------
  3971 
  3972 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3973 
  3974 * several changes of automated proof tools;
  3975 
  3976 * HOL: major changes to the inductive and datatype packages, including
  3977 some minor incompatibilities of theory syntax;
  3978 
  3979 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3980 called `inj_on';
  3981 
  3982 * HOL: removed duplicate thms in Arith:
  3983   less_imp_add_less  should be replaced by  trans_less_add1
  3984   le_imp_add_le      should be replaced by  trans_le_add1
  3985 
  3986 * HOL: unary minus is now overloaded (new type constraints may be
  3987 required);
  3988 
  3989 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3990 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3991 now taken as an integer constant.
  3992 
  3993 * Pure: ML function 'theory_of' renamed to 'theory';
  3994 
  3995 
  3996 *** Proof tools ***
  3997 
  3998 * Simplifier:
  3999   1. Asm_full_simp_tac is now more aggressive.
  4000      1. It will sometimes reorient premises if that increases their power to
  4001         simplify.
  4002      2. It does no longer proceed strictly from left to right but may also
  4003         rotate premises to achieve further simplification.
  4004      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4005      old Asm_full_simp_tac in that it does not rotate premises.
  4006   2. The simplifier now knows a little bit about nat-arithmetic.
  4007 
  4008 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4009 allows for selected deletion of wrappers, by introduction of names for
  4010 wrapper functionals.  This implies that addbefore, addSbefore,
  4011 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4012 and that adding two tactics with the same name overwrites the first
  4013 one (emitting a warning).
  4014   type wrapper = (int -> tactic) -> (int -> tactic)
  4015   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4016   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4017   delWrapper, delSWrapper: claset *  string            -> claset
  4018   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4019 
  4020 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4021 semantics; addbefore now affects only the unsafe part of step_tac
  4022 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4023 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4024 by Force_tac;
  4025 
  4026 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4027 compWrapper; added safe wrapper (and access functions for it);
  4028 
  4029 * HOL/split_all_tac is now much faster and fails if there is nothing
  4030 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4031 and the names of the automatically generated variables have changed.
  4032 split_all_tac has moved within claset() from unsafe wrappers to safe
  4033 wrappers, which means that !!-bound variables are split much more
  4034 aggressively, and safe_tac and clarify_tac now split such variables.
  4035 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4036 Note: the same holds for record_split_tac, which does the job of
  4037 split_all_tac for record fields.
  4038 
  4039 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4040 permanently to the default simpset using Addsplits just like
  4041 Addsimps. They can be removed via Delsplits just like
  4042 Delsimps. Lower-case versions are also available.
  4043 
  4044 * HOL/Simplifier: The rule split_if is now part of the default
  4045 simpset. This means that the simplifier will eliminate all occurrences
  4046 of if-then-else in the conclusion of a goal. To prevent this, you can
  4047 either remove split_if completely from the default simpset by
  4048 `Delsplits [split_if]' or remove it in a specific call of the
  4049 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4050 other case splitting rules to/from the default simpset: every datatype
  4051 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4052 t is the name of the datatype).
  4053 
  4054 * Classical reasoner / Simplifier combination: new force_tac (and
  4055 derivatives Force_tac, force) combines rewriting and classical
  4056 reasoning (and whatever other tools) similarly to auto_tac, but is
  4057 aimed to solve the given subgoal completely.
  4058 
  4059 
  4060 *** General ***
  4061 
  4062 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4063 and `goalw': the theory is no longer needed as an explicit argument -
  4064 the current theory context is used; assumptions are no longer returned
  4065 at the ML-level unless one of them starts with ==> or !!; it is
  4066 recommended to convert to these new commands using isatool fixgoal
  4067 (backup your sources first!);
  4068 
  4069 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4070 the current theory context, and 'theory' to lookup stored theories;
  4071 
  4072 * new theory section 'locale' for declaring constants, assumptions and
  4073 definitions that have local scope;
  4074 
  4075 * new theory section 'nonterminals' for purely syntactic types;
  4076 
  4077 * new theory section 'setup' for generic ML setup functions
  4078 (e.g. package initialization);
  4079 
  4080 * the distribution now includes Isabelle icons: see
  4081 lib/logo/isabelle-{small,tiny}.xpm;
  4082 
  4083 * isatool install - install binaries with absolute references to
  4084 ISABELLE_HOME/bin;
  4085 
  4086 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4087 
  4088 * print mode 'emacs' reserved for Isamode;
  4089 
  4090 * support multiple print (ast) translations per constant name;
  4091 
  4092 * theorems involving oracles are now printed with a suffixed [!];
  4093 
  4094 
  4095 *** HOL ***
  4096 
  4097 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4098 
  4099 * HOL/inductive package reorganized and improved: now supports mutual
  4100 definitions such as
  4101 
  4102   inductive EVEN ODD
  4103     intrs
  4104       null "0 : EVEN"
  4105       oddI "n : EVEN ==> Suc n : ODD"
  4106       evenI "n : ODD ==> Suc n : EVEN"
  4107 
  4108 new theorem list "elims" contains an elimination rule for each of the
  4109 recursive sets; inductive definitions now handle disjunctive premises
  4110 correctly (also ZF);
  4111 
  4112 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4113 "mutual_induct" no longer exists - the induction rule is always
  4114 contained in "induct";
  4115 
  4116 
  4117 * HOL/datatype package re-implemented and greatly improved: now
  4118 supports mutually recursive datatypes such as
  4119 
  4120   datatype
  4121     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4122             | SUM ('a aexp) ('a aexp)
  4123             | DIFF ('a aexp) ('a aexp)
  4124             | NUM 'a
  4125   and
  4126     'a bexp = LESS ('a aexp) ('a aexp)
  4127             | AND ('a bexp) ('a bexp)
  4128             | OR ('a bexp) ('a bexp)
  4129 
  4130 as well as indirectly recursive datatypes such as
  4131 
  4132   datatype
  4133     ('a, 'b) term = Var 'a
  4134                   | App 'b ((('a, 'b) term) list)
  4135 
  4136 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4137 induction on mutually / indirectly recursive datatypes.
  4138 
  4139 Primrec equations are now stored in theory and can be accessed via
  4140 <function_name>.simps.
  4141 
  4142 INCOMPATIBILITIES:
  4143 
  4144   - Theories using datatypes must now have theory Datatype as an
  4145     ancestor.
  4146   - The specific <typename>.induct_tac no longer exists - use the
  4147     generic induct_tac instead.
  4148   - natE has been renamed to nat.exhaust - use exhaust_tac
  4149     instead of res_inst_tac ... natE. Note that the variable
  4150     names in nat.exhaust differ from the names in natE, this
  4151     may cause some "fragile" proofs to fail.
  4152   - The theorems split_<typename>_case and split_<typename>_case_asm
  4153     have been renamed to <typename>.split and <typename>.split_asm.
  4154   - Since default sorts of type variables are now handled correctly,
  4155     some datatype definitions may have to be annotated with explicit
  4156     sort constraints.
  4157   - Primrec definitions no longer require function name and type
  4158     of recursive argument.
  4159 
  4160 Consider using isatool fixdatatype to adapt your theories and proof
  4161 scripts to the new package (backup your sources first!).
  4162 
  4163 
  4164 * HOL/record package: considerably improved implementation; now
  4165 includes concrete syntax for record types, terms, updates; theorems
  4166 for surjective pairing and splitting !!-bound record variables; proof
  4167 support is as follows:
  4168 
  4169   1) standard conversions (selectors or updates applied to record
  4170 constructor terms) are part of the standard simpset;
  4171 
  4172   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4173 made part of standard simpset and claset via addIffs;
  4174 
  4175   3) a tactic for record field splitting (record_split_tac) is part of
  4176 the standard claset (addSWrapper);
  4177 
  4178 To get a better idea about these rules you may retrieve them via
  4179 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4180 the name of your record type.
  4181 
  4182 The split tactic 3) conceptually simplifies by the following rule:
  4183 
  4184   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4185 
  4186 Thus any record variable that is bound by meta-all will automatically
  4187 blow up into some record constructor term, consequently the
  4188 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4189 solve record problems automatically.
  4190 
  4191 
  4192 * reorganized the main HOL image: HOL/Integ and String loaded by
  4193 default; theory Main includes everything;
  4194 
  4195 * automatic simplification of integer sums and comparisons, using cancellation;
  4196 
  4197 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4198 
  4199 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4200 
  4201 * many new identities for unions, intersections, set difference, etc.;
  4202 
  4203 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4204 called split_if, split_split, split_sum_case and split_nat_case (to go
  4205 with add/delsplits);
  4206 
  4207 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4208 (?x::unit) = (); this is made part of the default simpset, which COULD
  4209 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4210 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4211 unit_abs_eta_conv is added in order to counter the effect of
  4212 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4213 %u.f();
  4214 
  4215 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4216 makes more sense);
  4217 
  4218 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4219   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4220   disjointness reasoning but breaking a few old proofs.
  4221 
  4222 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4223 to 'converse' from 'inverse' (for compatibility with ZF and some
  4224 literature);
  4225 
  4226 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4227 the well-founded relation;
  4228 
  4229 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4230     Compl A.  The "Compl" syntax remains available as input syntax for this
  4231     release ONLY.
  4232 
  4233 * HOL/Update: new theory of function updates:
  4234     f(a:=b) == %x. if x=a then b else f x
  4235 may also be iterated as in f(a:=b,c:=d,...);
  4236 
  4237 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4238 
  4239 * HOL/List:
  4240   - new function list_update written xs[i:=v] that updates the i-th
  4241     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4242   - new function `upt' written [i..j(] which generates the list
  4243     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4244     bound write [i..j], which is a shorthand for [i..j+1(].
  4245   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4246 
  4247 * HOL/Arith:
  4248   - removed 'pred' (predecessor) function;
  4249   - generalized some theorems about n-1;
  4250   - many new laws about "div" and "mod";
  4251   - new laws about greatest common divisors (see theory ex/Primes);
  4252 
  4253 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4254 instead of "inverse";
  4255 
  4256 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4257   of the multiset ordering;
  4258 
  4259 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4260   (not included by default);
  4261 
  4262 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4263 
  4264 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4265   programs, i.e. different program variables may have different types.
  4266 
  4267 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4268   [previously, this check worked only if the rewrite rule was unconditional]
  4269   Now rew can involve either definitions or equalities (either == or =).
  4270 
  4271 
  4272 *** ZF ***
  4273 
  4274 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4275   only the theorems proved on ZF.ML;
  4276 
  4277 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4278   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4279   disjointness reasoning but breaking a few old proofs.
  4280 
  4281 * ZF/Update: new theory of function updates
  4282     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4283   may also be iterated as in f(a:=b,c:=d,...);
  4284 
  4285 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4286 
  4287 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4288   [previously, this check worked only if the rewrite rule was unconditional]
  4289   Now rew can involve either definitions or equalities (either == or =).
  4290 
  4291 * case_tac provided for compatibility with HOL
  4292     (like the old excluded_middle_tac, but with subgoals swapped)
  4293 
  4294 
  4295 *** Internal programming interfaces ***
  4296 
  4297 * Pure: several new basic modules made available for general use, see
  4298 also src/Pure/README;
  4299 
  4300 * improved the theory data mechanism to support encapsulation (data
  4301 kind name replaced by private Object.kind, acting as authorization
  4302 key); new type-safe user interface via functor TheoryDataFun; generic
  4303 print_data function becomes basically useless;
  4304 
  4305 * removed global_names compatibility flag -- all theory declarations
  4306 are qualified by default;
  4307 
  4308 * module Pure/Syntax now offers quote / antiquote translation
  4309 functions (useful for Hoare logic etc. with implicit dependencies);
  4310 see HOL/ex/Antiquote for an example use;
  4311 
  4312 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4313 cterm -> thm;
  4314 
  4315 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4316 subgoal;
  4317 
  4318 * Display.print_goals function moved to Locale.print_goals;
  4319 
  4320 * standard print function for goals supports current_goals_markers
  4321 variable for marking begin of proof, end of proof, start of goal; the
  4322 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4323 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4324 for example;
  4325 
  4326 
  4327 
  4328 New in Isabelle98 (January 1998)
  4329 --------------------------------
  4330 
  4331 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4332 
  4333 * changed lexical syntax of terms / types: dots made part of long
  4334 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4335 
  4336 * simpset (and claset) reference variable replaced by functions
  4337 simpset / simpset_ref;
  4338 
  4339 * no longer supports theory aliases (via merge) and non-trivial
  4340 implicit merge of thms' signatures;
  4341 
  4342 * most internal names of constants changed due to qualified names;
  4343 
  4344 * changed Pure/Sequence interface (see Pure/seq.ML);
  4345 
  4346 
  4347 *** General Changes ***
  4348 
  4349 * hierachically structured name spaces (for consts, types, axms, thms
  4350 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4351 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4352 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4353 long_names for fully qualified output names; NOTE: ML programs
  4354 (special tactics, packages etc.) referring to internal names may have
  4355 to be adapted to cope with fully qualified names; in case of severe
  4356 backward campatibility problems try setting 'global_names' at compile
  4357 time to have enrything declared within a flat name space; one may also
  4358 fine tune name declarations in theories via the 'global' and 'local'
  4359 section;
  4360 
  4361 * reimplemented the implicit simpset and claset using the new anytype
  4362 data filed in signatures; references simpset:simpset ref etc. are
  4363 replaced by functions simpset:unit->simpset and
  4364 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4365 to patch your ML files accordingly;
  4366 
  4367 * HTML output now includes theory graph data for display with Java
  4368 applet or isatool browser; data generated automatically via isatool
  4369 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4370 
  4371 * defs may now be conditional; improved rewrite_goals_tac to handle
  4372 conditional equations;
  4373 
  4374 * defs now admits additional type arguments, using TYPE('a) syntax;
  4375 
  4376 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4377 creates a new theory node; implicit merge of thms' signatures is
  4378 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4379 transfer:theory->thm->thm in (rare) cases;
  4380 
  4381 * improved handling of draft signatures / theories; draft thms (and
  4382 ctyps, cterms) are automatically promoted to real ones;
  4383 
  4384 * slightly changed interfaces for oracles: admit many per theory, named
  4385 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4386 
  4387 * print_goals: optional output of const types (set show_consts and
  4388 show_types);
  4389 
  4390 * improved output of warnings (###) and errors (***);
  4391 
  4392 * subgoal_tac displays a warning if the new subgoal has type variables;
  4393 
  4394 * removed old README and Makefiles;
  4395 
  4396 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4397 
  4398 * removed obsolete init_pps and init_database;
  4399 
  4400 * deleted the obsolete tactical STATE, which was declared by
  4401     fun STATE tacfun st = tacfun st st;
  4402 
  4403 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4404 (which abbreviates $HOME);
  4405 
  4406 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4407 use isatool fixseq to adapt your ML programs (this works for fully
  4408 qualified references to the Sequence structure only!);
  4409 
  4410 * use_thy no longer requires writable current directory; it always
  4411 reloads .ML *and* .thy file, if either one is out of date;
  4412 
  4413 
  4414 *** Classical Reasoner ***
  4415 
  4416 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4417 tactics that use classical reasoning to simplify a subgoal without
  4418 splitting it into several subgoals;
  4419 
  4420 * Safe_tac: like safe_tac but uses the default claset;
  4421 
  4422 
  4423 *** Simplifier ***
  4424 
  4425 * added simplification meta rules:
  4426     (asm_)(full_)simplify: simpset -> thm -> thm;
  4427 
  4428 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4429 logics (again);
  4430 
  4431 * added prems argument to simplification procedures;
  4432 
  4433 * HOL, FOL, ZF: added infix function `addsplits':
  4434   instead of `<simpset> setloop (split_tac <thms>)'
  4435   you can simply write `<simpset> addsplits <thms>'
  4436 
  4437 
  4438 *** Syntax ***
  4439 
  4440 * TYPE('a) syntax for type reflection terms;
  4441 
  4442 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4443 
  4444 * pretty printer: changed order of mixfix annotation preference (again!);
  4445 
  4446 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4447 
  4448 
  4449 *** HOL ***
  4450 
  4451 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4452   with `addloop' of the simplifier to faciliate case splitting in premises.
  4453 
  4454 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4455 
  4456 * HOL/Auth: new protocol proofs including some for the Internet
  4457   protocol TLS;
  4458 
  4459 * HOL/Map: new theory of `maps' a la VDM;
  4460 
  4461 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4462 cancelling out common nat summands from =, <, <= (in)equalities, or
  4463 differences; simplification procedures nat_cancel_factor for
  4464 cancelling common factor from =, <, <= (in)equalities over natural
  4465 sums; nat_cancel contains both kinds of procedures, it is installed by
  4466 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4467 
  4468 * HOL/simplifier: terms of the form
  4469   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4470   are rewritten to
  4471   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4472   and those of the form
  4473   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4474   are rewritten to
  4475   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4476 
  4477 * HOL/datatype
  4478   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4479 
  4480   P(t_case f1 ... fn x) =
  4481      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4482         ...
  4483        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4484      )
  4485 
  4486   and a theorem `split_t_case_asm' of the form
  4487 
  4488   P(t_case f1 ... fn x) =
  4489     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4490         ...
  4491        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4492      )
  4493   which can be added to a simpset via `addsplits'. The existing theorems
  4494   expand_list_case and expand_option_case have been renamed to
  4495   split_list_case and split_option_case.
  4496 
  4497 * HOL/Arithmetic:
  4498   - `pred n' is automatically converted to `n-1'.
  4499     Users are strongly encouraged not to use `pred' any longer,
  4500     because it will disappear altogether at some point.
  4501   - Users are strongly encouraged to write "0 < n" rather than
  4502     "n ~= 0". Theorems and proof tools have been modified towards this
  4503     `standard'.
  4504 
  4505 * HOL/Lists:
  4506   the function "set_of_list" has been renamed "set" (and its theorems too);
  4507   the function "nth" now takes its arguments in the reverse order and
  4508   has acquired the infix notation "!" as in "xs!n".
  4509 
  4510 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4511 
  4512 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4513   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4514 
  4515 * HOL/record: extensible records with schematic structural subtyping
  4516 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4517 still lacks various theorems and concrete record syntax;
  4518 
  4519 
  4520 *** HOLCF ***
  4521 
  4522 * removed "axioms" and "generated by" sections;
  4523 
  4524 * replaced "ops" section by extended "consts" section, which is capable of
  4525   handling the continuous function space "->" directly;
  4526 
  4527 * domain package:
  4528   . proves theorems immediately and stores them in the theory,
  4529   . creates hierachical name space,
  4530   . now uses normal mixfix annotations (instead of cinfix...),
  4531   . minor changes to some names and values (for consistency),
  4532   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4533   . separator between mutual domain defs: changed "," to "and",
  4534   . improved handling of sort constraints;  now they have to
  4535     appear on the left-hand side of the equations only;
  4536 
  4537 * fixed LAM <x,y,zs>.b syntax;
  4538 
  4539 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4540 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4541 
  4542 
  4543 *** FOL and ZF ***
  4544 
  4545 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4546   with `addloop' of the simplifier to faciliate case splitting in premises.
  4547 
  4548 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4549 in HOL, they strip ALL and --> from proved theorems;
  4550 
  4551 
  4552 
  4553 New in Isabelle94-8 (May 1997)
  4554 ------------------------------
  4555 
  4556 *** General Changes ***
  4557 
  4558 * new utilities to build / run / maintain Isabelle etc. (in parts
  4559 still somewhat experimental); old Makefiles etc. still functional;
  4560 
  4561 * new 'Isabelle System Manual';
  4562 
  4563 * INSTALL text, together with ./configure and ./build scripts;
  4564 
  4565 * reimplemented type inference for greater efficiency, better error
  4566 messages and clean internal interface;
  4567 
  4568 * prlim command for dealing with lots of subgoals (an easier way of
  4569 setting goals_limit);
  4570 
  4571 
  4572 *** Syntax ***
  4573 
  4574 * supports alternative (named) syntax tables (parser and pretty
  4575 printer); internal interface is provided by add_modesyntax(_i);
  4576 
  4577 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4578 be used in conjunction with the Isabelle symbol font; uses the
  4579 "symbols" syntax table;
  4580 
  4581 * added token_translation interface (may translate name tokens in
  4582 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4583 the current print_mode); IMPORTANT: user print translation functions
  4584 are responsible for marking newly introduced bounds
  4585 (Syntax.mark_boundT);
  4586 
  4587 * token translations for modes "xterm" and "xterm_color" that display
  4588 names in bold, underline etc. or colors (which requires a color
  4589 version of xterm);
  4590 
  4591 * infixes may now be declared with names independent of their syntax;
  4592 
  4593 * added typed_print_translation (like print_translation, but may
  4594 access type of constant);
  4595 
  4596 
  4597 *** Classical Reasoner ***
  4598 
  4599 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4600 some limitations.  Blast_tac...
  4601   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4602   + ignores elimination rules that don't have the correct format
  4603         (the conclusion MUST be a formula variable)
  4604   + ignores types, which can make HOL proofs fail
  4605   + rules must not require higher-order unification, e.g. apply_type in ZF
  4606     [message "Function Var's argument not a bound variable" relates to this]
  4607   + its proof strategy is more general but can actually be slower
  4608 
  4609 * substitution with equality assumptions no longer permutes other
  4610 assumptions;
  4611 
  4612 * minor changes in semantics of addafter (now called addaltern); renamed
  4613 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4614 (and access functions for it);
  4615 
  4616 * improved combination of classical reasoner and simplifier:
  4617   + functions for handling clasimpsets
  4618   + improvement of addss: now the simplifier is called _after_ the
  4619     safe steps.
  4620   + safe variant of addss called addSss: uses safe simplifications
  4621     _during_ the safe steps. It is more complete as it allows multiple
  4622     instantiations of unknowns (e.g. with slow_tac).
  4623 
  4624 *** Simplifier ***
  4625 
  4626 * added interface for simplification procedures (functions that
  4627 produce *proven* rewrite rules on the fly, depending on current
  4628 redex);
  4629 
  4630 * ordering on terms as parameter (used for ordered rewriting);
  4631 
  4632 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4633 
  4634 * the solver is now split into a safe and an unsafe part.
  4635 This should be invisible for the normal user, except that the
  4636 functions setsolver and addsolver have been renamed to setSolver and
  4637 addSolver; added safe_asm_full_simp_tac;
  4638 
  4639 
  4640 *** HOL ***
  4641 
  4642 * a generic induction tactic `induct_tac' which works for all datatypes and
  4643 also for type `nat';
  4644 
  4645 * a generic case distinction tactic `exhaust_tac' which works for all
  4646 datatypes and also for type `nat';
  4647 
  4648 * each datatype comes with a function `size';
  4649 
  4650 * patterns in case expressions allow tuple patterns as arguments to
  4651 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4652 
  4653 * primrec now also works with type nat;
  4654 
  4655 * recdef: a new declaration form, allows general recursive functions to be
  4656 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4657 
  4658 * the constant for negation has been renamed from "not" to "Not" to
  4659 harmonize with FOL, ZF, LK, etc.;
  4660 
  4661 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4662 infinite lists;
  4663 
  4664 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4665 
  4666 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4667 problems in commutative rings, using axiomatic type classes for + and *;
  4668 
  4669 * more examples in HOL/MiniML and HOL/Auth;
  4670 
  4671 * more default rewrite rules for quantifiers, union/intersection;
  4672 
  4673 * a new constant `arbitrary == @x.False';
  4674 
  4675 * HOLCF/IOA replaces old HOL/IOA;
  4676 
  4677 * HOLCF changes: derived all rules and arities
  4678   + axiomatic type classes instead of classes
  4679   + typedef instead of faking type definitions
  4680   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4681   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4682   + eliminated the types void, one, tr
  4683   + use unit lift and bool lift (with translations) instead of one and tr
  4684   + eliminated blift from Lift3.thy (use Def instead of blift)
  4685   all eliminated rules are derived as theorems --> no visible changes ;
  4686 
  4687 
  4688 *** ZF ***
  4689 
  4690 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4691 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4692 as ZF_cs addSIs [equalityI];
  4693 
  4694 
  4695 
  4696 New in Isabelle94-7 (November 96)
  4697 ---------------------------------
  4698 
  4699 * allowing negative levels (as offsets) in prlev and choplev;
  4700 
  4701 * super-linear speedup for large simplifications;
  4702 
  4703 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4704 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4705 FAIL); can suppress it using the command Delsimps (ex_simps @
  4706 all_simps); De Morgan laws are also now included, by default;
  4707 
  4708 * improved printing of ==>  :  ~:
  4709 
  4710 * new object-logic "Sequents" adds linear logic, while replacing LK
  4711 and Modal (thanks to Sara Kalvala);
  4712 
  4713 * HOL/Auth: correctness proofs for authentication protocols;
  4714 
  4715 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4716 examples on HOL/Auth);
  4717 
  4718 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4719 the rewriter and classical reasoner simultaneously;
  4720 
  4721 * function uresult no longer returns theorems in "standard" format;
  4722 regain previous version by: val uresult = standard o uresult;
  4723 
  4724 
  4725 
  4726 New in Isabelle94-6
  4727 -------------------
  4728 
  4729 * oracles -- these establish an interface between Isabelle and trusted
  4730 external reasoners, which may deliver results as theorems;
  4731 
  4732 * proof objects (in particular record all uses of oracles);
  4733 
  4734 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4735 
  4736 * "constdefs" section in theory files;
  4737 
  4738 * "primrec" section (HOL) no longer requires names;
  4739 
  4740 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4741 
  4742 
  4743 
  4744 New in Isabelle94-5
  4745 -------------------
  4746 
  4747 * reduced space requirements;
  4748 
  4749 * automatic HTML generation from theories;
  4750 
  4751 * theory files no longer require "..." (quotes) around most types;
  4752 
  4753 * new examples, including two proofs of the Church-Rosser theorem;
  4754 
  4755 * non-curried (1994) version of HOL is no longer distributed;
  4756 
  4757 
  4758 
  4759 New in Isabelle94-4
  4760 -------------------
  4761 
  4762 * greatly reduced space requirements;
  4763 
  4764 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4765 
  4766 * searchable theorem database (see the section "Retrieving theorems" on
  4767 page 8 of the Reference Manual);
  4768 
  4769 * new examples, including Grabczewski's monumental case study of the
  4770 Axiom of Choice;
  4771 
  4772 * The previous version of HOL renamed to Old_HOL;
  4773 
  4774 * The new version of HOL (previously called CHOL) uses a curried syntax
  4775 for functions.  Application looks like f a b instead of f(a,b);
  4776 
  4777 * Mutually recursive inductive definitions finally work in HOL;
  4778 
  4779 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4780 translates to the operator "split";
  4781 
  4782 
  4783 
  4784 New in Isabelle94-3
  4785 -------------------
  4786 
  4787 * new infix operator, addss, allowing the classical reasoner to
  4788 perform simplification at each step of its search.  Example:
  4789         fast_tac (cs addss ss)
  4790 
  4791 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4792 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4793 look like (a,b) instead of <a,b>;
  4794 
  4795 * PLEASE NOTE: CHOL will eventually replace HOL!
  4796 
  4797 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4798 It translates to the operator "split".  A new theory of integers is available;
  4799 
  4800 * In ZF, integer numerals now denote two's-complement binary integers.
  4801 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4802 
  4803 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4804 of the Axiom of Choice;
  4805 
  4806 
  4807 
  4808 New in Isabelle94-2
  4809 -------------------
  4810 
  4811 * Significantly faster resolution;
  4812 
  4813 * the different sections in a .thy file can now be mixed and repeated
  4814 freely;
  4815 
  4816 * Database of theorems for FOL, HOL and ZF.  New
  4817 commands including qed, qed_goal and bind_thm store theorems in the database.
  4818 
  4819 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4820 a given theory (thms_of), or find out what theory a theorem was proved in
  4821 (theory_of_thm);
  4822 
  4823 * Bugs fixed in the inductive definition and datatype packages;
  4824 
  4825 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4826 and HOL_dup_cs obsolete;
  4827 
  4828 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4829 have been removed;
  4830 
  4831 * Simpler definition of function space in ZF;
  4832 
  4833 * new results about cardinal and ordinal arithmetic in ZF;
  4834 
  4835 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4836 types;
  4837 
  4838 
  4839 $Id$