NEWS
author wenzelm
Sun Jul 29 19:46:03 2007 +0200 (2007-07-29)
changeset 24062 845c0d693328
parent 24032 b3d7eb6f535f
child 24086 21900a460ba4
permissions -rw-r--r--
explicit global state argument -- no longer CRITICAL;
     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 * Theory loader: be more serious about observing the static theory
    28 header specifications (including optional directories), but not the
    29 accidental file locations of previously successful loads.  Potential
    30 INCOMPATIBILITY, may need to refine theory headers.
    31 
    32 * Theory loader: optional support for content-based file
    33 identification, instead of the traditional scheme of full physical
    34 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
    35 (cf. the system manual).  The new scheme allows to work with
    36 non-finished theories in persistent session images, such that source
    37 files may be moved later on without requiring reloads.
    38 
    39 * Legacy goal package: reduced interface to the bare minimum required
    40 to keep existing proof scripts running.  Most other user-level
    41 functions are now part of the OldGoals structure, which is *not* open
    42 by default (consider isatool expandshort before open OldGoals).
    43 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    44 these tend to cause confusion about the actual goal (!) context being
    45 used here, which is not necessarily the same as the_context().
    46 
    47 * Command 'find_theorems': supports "*" wild-card in "name:"
    48 criterion; "with_dups" option.  Certain ProofGeneral versions might
    49 support a specific search form (see ProofGeneral/CHANGES).
    50 
    51 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    52 by default, which means that "prems" (and also "fixed variables") are
    53 suppressed from proof state output.  Note that the ProofGeneral
    54 settings mechanism allows to change and save options persistently, but
    55 older versions of Isabelle will fail to start up if a negative prems
    56 limit is imposed.
    57 
    58 * Local theory targets may be specified by non-nested blocks of
    59 ``context/locale/class ... begin'' followed by ``end''.  The body may
    60 contain definitions, theorems etc., including any derived mechanism
    61 that has been implemented on top of these primitives.  This concept
    62 generalizes the existing ``theorem (in ...)'' towards more versatility
    63 and scalability.
    64 
    65 * Proof General interface: proper undo of final 'end' command;
    66 discontinued Isabelle/classic mode (ML proof scripts).
    67 
    68 
    69 *** Document preparation ***
    70 
    71 * Added antiquotation @{theory name} which prints the given name,
    72 after checking that it refers to a valid ancestor theory in the
    73 current context.
    74 
    75 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    76 check the given source text as ML type/structure, printing verbatim.
    77 
    78 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    79 "c args == rhs" given in the current context.  (Any number of
    80 arguments may be given on the LHS.)
    81 
    82 
    83 
    84 *** Pure ***
    85 
    86 * code generator: consts in 'consts_code' Isar commands are now referred
    87   to by usual term syntax (including optional type annotations).
    88 
    89 * code generator: 
    90   - Isar 'definition's, 'constdef's and primitive instance definitions are added
    91     explicitly to the table of defining equations
    92   - primitive definitions are not used as defining equations by default any longer
    93   - defining equations are now definitly restricted to meta "==" and object
    94         equality "="
    95   - HOL theories have been adopted accordingly
    96 
    97 * class_package.ML offers a combination of axclasses and locales to
    98 achieve Haskell-like type classes in Isabelle.  See
    99 HOL/ex/Classpackage.thy for examples.
   100 
   101 * Yet another code generator framework allows to generate executable
   102 code for ML and Haskell (including "class"es).  A short usage sketch:
   103 
   104     internal compilation:
   105         code_gen <list of constants (term syntax)> in SML
   106     writing SML code to a file:
   107         code_gen <list of constants (term syntax)> in SML <filename>
   108     writing OCaml code to a file:
   109         code_gen <list of constants (term syntax)> in OCaml <filename>
   110     writing Haskell code to a bunch of files:
   111         code_gen <list of constants (term syntax)> in Haskell <filename>
   112 
   113 Reasonable default setup of framework in HOL/Main.
   114 
   115 Theorem attributs for selecting and transforming function equations theorems:
   116 
   117     [code fun]:        select a theorem as function equation for a specific constant
   118     [code fun del]:    deselect a theorem as function equation for a specific constant
   119     [code inline]:     select an equation theorem for unfolding (inlining) in place
   120     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   121 
   122 User-defined serializations (target in {SML, OCaml, Haskell}):
   123 
   124     code_const <and-list of constants (term syntax)>
   125       {(target) <and-list of const target syntax>}+
   126 
   127     code_type <and-list of type constructors>
   128       {(target) <and-list of type target syntax>}+
   129 
   130     code_instance <and-list of instances>
   131       {(target)}+
   132         where instance ::= <type constructor> :: <class>
   133 
   134     code_class <and_list of classes>
   135       {(target) <and-list of class target syntax>}+
   136         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   137 
   138 code_instance and code_class only apply to target Haskell.
   139 
   140 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   141 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   142 
   143 * Command 'no_translations' removes translation rules from theory
   144 syntax.
   145 
   146 * Overloaded definitions are now actually checked for acyclic
   147 dependencies.  The overloading scheme is slightly more general than
   148 that of Haskell98, although Isabelle does not demand an exact
   149 correspondence to type class and instance declarations.
   150 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   151 exotic versions of overloading -- at the discretion of the user!
   152 
   153 Polymorphic constants are represented via type arguments, i.e. the
   154 instantiation that matches an instance against the most general
   155 declaration given in the signature.  For example, with the declaration
   156 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   157 as c(nat).  Overloading is essentially simultaneous structural
   158 recursion over such type arguments.  Incomplete specification patterns
   159 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   160 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   161 Command 'print_theory' outputs the normalized system of recursive
   162 equations, see section "definitions".
   163 
   164 * Isar: command 'declaration' augments a local theory by generic
   165 declaration functions written in ML.  This enables arbitrary content
   166 being added to the context, depending on a morphism that tells the
   167 difference of the original declaration context wrt. the application
   168 context encountered later on.
   169 
   170 * Isar: proper interfaces for simplification procedures.  Command
   171 'simproc_setup' declares named simprocs (with match patterns, and body
   172 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   173 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   174 
   175 * Isar: an extra pair of brackets around attribute declarations
   176 abbreviates a theorem reference involving an internal dummy fact,
   177 which will be ignored later --- only the effect of the attribute on
   178 the background context will persist.  This form of in-place
   179 declarations is particularly useful with commands like 'declare' and
   180 'using', for example ``have A using [[simproc a]] by simp''.
   181 
   182 * Isar: method "assumption" (and implicit closing of subproofs) now
   183 takes simple non-atomic goal assumptions into account: after applying
   184 an assumption as a rule the resulting subgoals are solved by atomic
   185 assumption steps.  This is particularly useful to finish 'obtain'
   186 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   187 without referring to the original premise "!!x. P x ==> thesis" in the
   188 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   189 more permissive.
   190 
   191 * Isar: implicit use of prems from the Isar proof context is
   192 considered a legacy feature.  Common applications like ``have A .''
   193 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   194 referencing facts explicitly here improves readability and
   195 maintainability of proof texts.
   196 
   197 * Isar: improper proof element 'guess' is like 'obtain', but derives
   198 the obtained context from the course of reasoning!  For example:
   199 
   200   assume "EX x y. A x & B y"   -- "any previous fact"
   201   then guess x and y by clarify
   202 
   203 This technique is potentially adventurous, depending on the facts and
   204 proof tools being involved here.
   205 
   206 * Isar: known facts from the proof context may be specified as literal
   207 propositions, using ASCII back-quote syntax.  This works wherever
   208 named facts used to be allowed so far, in proof commands, proof
   209 methods, attributes etc.  Literal facts are retrieved from the context
   210 according to unification of type and term parameters.  For example,
   211 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   212 theorems in the current context, then these are valid literal facts:
   213 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   214 
   215 There is also a proof method "fact" which does the same composition
   216 for explicit goal states, e.g. the following proof texts coincide with
   217 certain special cases of literal facts:
   218 
   219   have "A" by fact                 ==  note `A`
   220   have "A ==> B" by fact           ==  note `A ==> B`
   221   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   222   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   223 
   224 * Isar: ":" (colon) is no longer a symbolic identifier character in
   225 outer syntax.  Thus symbolic identifiers may be used without
   226 additional white space in declarations like this: ``assume *: A''.
   227 
   228 * Isar: 'print_facts' prints all local facts of the current context,
   229 both named and unnamed ones.
   230 
   231 * Isar: 'def' now admits simultaneous definitions, e.g.:
   232 
   233   def x == "t" and y == "u"
   234 
   235 * Isar: added command 'unfolding', which is structurally similar to
   236 'using', but affects both the goal state and facts by unfolding given
   237 rewrite rules.  Thus many occurrences of the 'unfold' method or
   238 'unfolded' attribute may be replaced by first-class proof text.
   239 
   240 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   241 and command 'unfolding' now all support object-level equalities
   242 (potentially conditional).  The underlying notion of rewrite rule is
   243 analogous to the 'rule_format' attribute, but *not* that of the
   244 Simplifier (which is usually more generous).
   245 
   246 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   247 method expression within a sandbox consisting of the first N
   248 sub-goals, which need to exist.  For example, ``simp_all [3]''
   249 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   250 simplifies all new goals that emerge from applying rule foo to the
   251 originally first one.
   252 
   253 * Isar: schematic goals are no longer restricted to higher-order
   254 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   255 expected.
   256 
   257 * Isar: the conclusion of a long theorem statement is now either
   258 'shows' (a simultaneous conjunction, as before), or 'obtains'
   259 (essentially a disjunction of cases with local parameters and
   260 assumptions).  The latter allows to express general elimination rules
   261 adequately; in this notation common elimination rules look like this:
   262 
   263   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   264     assumes "EX x. P x"
   265     obtains x where "P x"
   266 
   267   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   268     assumes "A & B"
   269     obtains A and B
   270 
   271   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   272     assumes "A | B"
   273     obtains
   274       A
   275     | B
   276 
   277 The subsequent classical rules even refer to the formal "thesis"
   278 explicitly:
   279 
   280   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   281     obtains "~ thesis"
   282 
   283   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   284     obtains "thesis ==> something"
   285 
   286 The actual proof of an 'obtains' statement is analogous to that of the
   287 Isar proof element 'obtain', only that there may be several cases.
   288 Optional case names may be specified in parentheses; these will be
   289 available both in the present proof and as annotations in the
   290 resulting rule, for later use with the 'cases' method (cf. attribute
   291 case_names).
   292 
   293 * Isar: the assumptions of a long theorem statement are available as
   294 "assms" fact in the proof context.  This is more appropriate than the
   295 (historical) "prems", which refers to all assumptions of the current
   296 context, including those from the target locale, proof body etc.
   297 
   298 * Isar: 'print_statement' prints theorems from the current theory or
   299 proof context in long statement form, according to the syntax of a
   300 top-level lemma.
   301 
   302 * Isar: 'obtain' takes an optional case name for the local context
   303 introduction rule (default "that").
   304 
   305 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   306 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   307 to occur.
   308 
   309 * Pure: syntax "CONST name" produces a fully internalized constant
   310 according to the current context.  This is particularly useful for
   311 syntax translations that should refer to internal constant
   312 representations independently of name spaces.
   313 
   314 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   315 instead of "FOO ". This allows multiple binder declarations to coexist
   316 in the same context.  INCOMPATIBILITY.
   317 
   318 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   319 primitive that also works in a locale context (both for constants and
   320 fixed variables).  Type declaration and internal syntactic
   321 representation of given constants retrieved from the context.
   322 
   323 * Isar/locales: new derived specification elements 'axiomatization',
   324 'definition', 'abbreviation', which support type-inference, admit
   325 object-level specifications (equality, equivalence).  See also the
   326 isar-ref manual.  Examples:
   327 
   328   axiomatization
   329     eq  (infix "===" 50) where
   330     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   331 
   332   definition "f x y = x + y + 1"
   333   definition g where "g x = f x x"
   334 
   335   abbreviation
   336     neq  (infix "=!=" 50) where
   337     "x =!= y == ~ (x === y)"
   338 
   339 These specifications may be also used in a locale context.  Then the
   340 constants being introduced depend on certain fixed parameters, and the
   341 constant name is qualified by the locale base name.  An internal
   342 abbreviation takes care for convenient input and output, making the
   343 parameters implicit and using the original short name.  See also
   344 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   345 entities from a monomorphic theory.
   346 
   347 Presently, abbreviations are only available 'in' a target locale, but
   348 not inherited by general import expressions.  Also note that
   349 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   350 'translations' in common applications.
   351 
   352 Concrete syntax is attached to specified constants in internal form,
   353 independently of name spaces.  The parse tree representation is
   354 slightly different -- use 'notation' instead of raw 'syntax', and
   355 'translations' with explicit "CONST" markup to accommodate this.
   356 
   357 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   358 the current context.  Print mode "no_abbrevs" prevents inversion of
   359 abbreviations on output.
   360 
   361 * Isar/locales: improved parameter handling:
   362 - use of locales "var" and "struct" no longer necessary;
   363 - parameter renamings are no longer required to be injective.
   364   This enables, for example, to define a locale for endomorphisms thus:
   365   locale endom = homom mult mult h.
   366 
   367 * Isar/locales: changed the way locales with predicates are defined.
   368 Instead of accumulating the specification, the imported expression is
   369 now an interpretation.  INCOMPATIBILITY: different normal form of
   370 locale expressions.  In particular, in interpretations of locales with
   371 predicates, goals repesenting already interpreted fragments are not
   372 removed automatically.  Use methods `intro_locales' and
   373 `unfold_locales'; see below.
   374 
   375 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   376 provide backward reasoning on locales predicates.  The methods are
   377 aware of interpretations and discharge corresponding goals.
   378 `intro_locales' is less aggressive then `unfold_locales' and does not
   379 unfold predicates to assumptions.
   380 
   381 * Isar/locales: the order in which locale fragments are accumulated
   382 has changed.  This enables to override declarations from fragments due
   383 to interpretations -- for example, unwanted simp rules.
   384 
   385 * Isar/locales: interpretation in theories and proof contexts has been
   386 extended.  One may now specify (and prove) equations, which are
   387 unfolded in interpreted theorems.  This is useful for replacing
   388 defined concepts (constants depending on locale parameters) by
   389 concepts already existing in the target context.  Example:
   390 
   391   interpretation partial_order ["op <= :: [int, int] => bool"]
   392     where "partial_order.less (op <=) (x::int) y = (x < y)"
   393 
   394 Typically, the constant `partial_order.less' is created by a definition
   395 specification element in the context of locale partial_order.
   396 
   397 * Provers/induct: improved internal context management to support
   398 local fixes and defines on-the-fly.  Thus explicit meta-level
   399 connectives !! and ==> are rarely required anymore in inductive goals
   400 (using object-logic connectives for this purpose has been long
   401 obsolete anyway).  The subsequent proof patterns illustrate advanced
   402 techniques of natural induction; general datatypes and inductive sets
   403 work analogously (see also src/HOL/Lambda for realistic examples).
   404 
   405 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   406 parameters:
   407 
   408   lemma
   409     fixes n :: nat and x :: 'a
   410     assumes a: "A n x"
   411     shows "P n x"
   412     using a                     -- {* make induct insert fact a *}
   413   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   414     case 0
   415     show ?case sorry
   416   next
   417     case (Suc n)
   418     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   419     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   420     show ?case sorry
   421   qed
   422 
   423 (2) This is how to perform induction over ``expressions of a certain
   424 form'', using a locally defined inductive parameter n == "a x"
   425 together with strengthening (the latter is usually required to get
   426 sufficiently flexible induction hypotheses):
   427 
   428   lemma
   429     fixes a :: "'a => nat"
   430     assumes a: "A (a x)"
   431     shows "P (a x)"
   432     using a
   433   proof (induct n == "a x" arbitrary: x)
   434     ...
   435 
   436 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   437 particular technique.
   438 
   439 (3) This is how to perform existential reasoning ('obtains' or
   440 'obtain') by induction, while avoiding explicit object-logic
   441 encodings:
   442 
   443   lemma
   444     fixes n :: nat
   445     obtains x :: 'a where "P n x" and "Q n x"
   446   proof (induct n arbitrary: thesis)
   447     case 0
   448     obtain x where "P 0 x" and "Q 0 x" sorry
   449     then show thesis by (rule 0)
   450   next
   451     case (Suc n)
   452     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   453     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   454     then show thesis by (rule Suc.prems)
   455   qed
   456 
   457 Here the 'arbitrary: thesis' specification essentially modifies the
   458 scope of the formal thesis parameter, in order to the get the whole
   459 existence statement through the induction as expected.
   460 
   461 * Provers/induct: mutual induction rules are now specified as a list
   462 of rule sharing the same induction cases.  HOL packages usually
   463 provide foo_bar.inducts for mutually defined items foo and bar
   464 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   465 specify mutual induction rules differently, i.e. like this:
   466 
   467   (induct rule: foo_bar.inducts)
   468   (induct set: foo bar)
   469   (induct type: foo bar)
   470 
   471 The ML function ProjectRule.projections turns old-style rules into the
   472 new format.
   473 
   474 * Provers/induct: improved handling of simultaneous goals.  Instead of
   475 introducing object-level conjunction, the statement is now split into
   476 several conclusions, while the corresponding symbolic cases are
   477 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   478 explicitly.  For example:
   479 
   480   lemma
   481     fixes n :: nat
   482     shows "P n" and "Q n"
   483   proof (induct n)
   484     case 0 case 1
   485     show "P 0" sorry
   486   next
   487     case 0 case 2
   488     show "Q 0" sorry
   489   next
   490     case (Suc n) case 1
   491     note `P n` and `Q n`
   492     show "P (Suc n)" sorry
   493   next
   494     case (Suc n) case 2
   495     note `P n` and `Q n`
   496     show "Q (Suc n)" sorry
   497   qed
   498 
   499 The split into subcases may be deferred as follows -- this is
   500 particularly relevant for goal statements with local premises.
   501 
   502   lemma
   503     fixes n :: nat
   504     shows "A n ==> P n" and "B n ==> Q n"
   505   proof (induct n)
   506     case 0
   507     {
   508       case 1
   509       note `A 0`
   510       show "P 0" sorry
   511     next
   512       case 2
   513       note `B 0`
   514       show "Q 0" sorry
   515     }
   516   next
   517     case (Suc n)
   518     note `A n ==> P n` and `B n ==> Q n`
   519     {
   520       case 1
   521       note `A (Suc n)`
   522       show "P (Suc n)" sorry
   523     next
   524       case 2
   525       note `B (Suc n)`
   526       show "Q (Suc n)" sorry
   527     }
   528   qed
   529 
   530 If simultaneous goals are to be used with mutual rules, the statement
   531 needs to be structured carefully as a two-level conjunction, using
   532 lists of propositions separated by 'and':
   533 
   534   lemma
   535     shows "a : A ==> P1 a"
   536           "a : A ==> P2 a"
   537       and "b : B ==> Q1 b"
   538           "b : B ==> Q2 b"
   539           "b : B ==> Q3 b"
   540   proof (induct set: A B)
   541 
   542 * Provers/induct: support coinduction as well.  See
   543 src/HOL/Library/Coinductive_List.thy for various examples.
   544 
   545 * Attribute "symmetric" produces result with standardized schematic
   546 variables (index 0).  Potential INCOMPATIBILITY.
   547 
   548 * Simplifier: by default the simplifier trace only shows top level
   549 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   550 default. Thus there is less danger of being flooded by the trace. The
   551 trace indicates where parts have been suppressed.
   552   
   553 * Provers/classical: removed obsolete classical version of elim_format
   554 attribute; classical elim/dest rules are now treated uniformly when
   555 manipulating the claset.
   556 
   557 * Provers/classical: stricter checks to ensure that supplied intro,
   558 dest and elim rules are well-formed; dest and elim rules must have at
   559 least one premise.
   560 
   561 * Provers/classical: attributes dest/elim/intro take an optional
   562 weight argument for the rule (just as the Pure versions).  Weights are
   563 ignored by automated tools, but determine the search order of single
   564 rule steps.
   565 
   566 * Syntax: input syntax now supports dummy variable binding "%_. b",
   567 where the body does not mention the bound variable.  Note that dummy
   568 patterns implicitly depend on their context of bounds, which makes
   569 "{_. _}" match any set comprehension as expected.  Potential
   570 INCOMPATIBILITY -- parse translations need to cope with syntactic
   571 constant "_idtdummy" in the binding position.
   572 
   573 * Syntax: removed obsolete syntactic constant "_K" and its associated
   574 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   575 for example "A -> B" => "Pi A (%_. B)".
   576 
   577 * Pure: 'class_deps' command visualizes the subclass relation, using
   578 the graph browser tool.
   579 
   580 * Pure: 'print_theory' now suppresses entities with internal name
   581 (trailing "_") by default; use '!' option for full details.
   582 
   583 
   584 *** HOL ***
   585 
   586 * Code generator library theories:
   587   * Pretty_Int represents HOL integers by big integer literals in target
   588     languages.
   589   * Pretty_Char represents HOL characters by character literals in target
   590     languages.
   591   * Pretty_Char_chr like Pretty_Char, but also offers treatment of character
   592     codes; includes Pretty_Int.
   593   * Executable_Set allows to generate code for finite sets using lists.
   594   * Executable_Rat implements rational numbers as triples (sign, enumerator,
   595     denominator).
   596   * Executable_Real implements a subset of real numbers, namly those
   597     representable by rational numbers.
   598   * Efficient_Nat implements natural numbers by integers, which in general will
   599     result in higher efficency; pattern matching with 0/Suc is eliminated;
   600     includes Pretty_Int.
   601   * ML_String provides an additional datatype ml_string; in the HOL default
   602     setup, strings in HOL are mapped to lists of HOL characters in SML; values
   603     of type ml_string are mapped to strings in SML.
   604   * ML_Int provides an additional datatype ml_int which is mapped to to SML
   605     built-in integers.
   606 
   607 * New package for inductive predicates
   608 
   609   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
   610 
   611     inductive
   612       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   613       for z_1 :: U_1 and ... and z_n :: U_m
   614     where
   615       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   616     | ...
   617 
   618   rather than
   619 
   620     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   621 
   622     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   623     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   624 
   625     inductive "s z_1 ... z_m"
   626     intros
   627       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   628       ...
   629 
   630   For backward compatibility, there is a wrapper allowing inductive
   631   sets to be defined with the new package via
   632 
   633     inductive_set
   634       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   635       for z_1 :: U_1 and ... and z_n :: U_m
   636     where
   637       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   638     | ...
   639 
   640   or
   641 
   642     inductive_set
   643       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   644       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   645       for z_1 :: U_1 and ... and z_n :: U_m
   646     where
   647       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   648     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   649     | ...
   650 
   651   if the additional syntax "p ..." is required.
   652 
   653   Many examples can be found in the subdirectories Auth, Bali, Induct,
   654   or MicroJava.
   655 
   656   INCOMPATIBILITIES:
   657 
   658   - Since declaration and definition of inductive sets or predicates
   659     is no longer separated, abbreviations involving the newly introduced
   660     sets or predicates must be specified together with the introduction
   661     rules after the "where" keyword (see example above), rather than before
   662     the actual inductive definition.
   663 
   664   - The variables in induction and elimination rules are now quantified
   665     in the order of their occurrence in the introduction rules, rather than
   666     in alphabetical order. Since this may break some proofs, these proofs
   667     either have to be repaired, e.g. by reordering the variables
   668     a_i_1 ... a_i_{k_i} in Isar "case" statements of the form
   669 
   670       case (rule_i a_i_1 ... a_i_{k_i})
   671 
   672     or the old order of quantification has to be restored by explicitly adding
   673     meta-level quantifiers in the introduction rules, i.e.
   674 
   675       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
   676 
   677   - The format of the elimination rules is now
   678 
   679       p z_1 ... z_m x_1 ... x_n ==>
   680         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   681         ==> ... ==> P
   682 
   683     for predicates and
   684 
   685       (x_1, ..., x_n) : s z_1 ... z_m ==>
   686         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   687         ==> ... ==> P
   688 
   689     for sets rather than
   690 
   691       x : s z_1 ... z_m ==>
   692         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
   693         ==> ... ==> P
   694 
   695     This may require terms in goals to be expanded to n-tuples (e.g. using case_tac
   696     or simplification with the split_paired_all rule) before the above elimination
   697     rule is applicable.
   698 
   699   - The elimination or case analysis rules for (mutually) inductive sets or
   700     predicates are now called "p_1.cases" ... "p_k.cases". The list of rules
   701     "p_1_..._p_k.elims" is no longer available.
   702 
   703 * Method "metis" proves goals by applying the Metis general-purpose
   704 resolution prover.  Examples are in the directory MetisExamples.  See
   705 also http://gilith.com/software/metis/
   706   
   707 * Command 'sledgehammer' invokes external automatic theorem provers as
   708 background processes.  It generates calls to the "metis" method if
   709 successful. These can be pasted into the proof.  Users do not have to
   710 wait for the automatic provers to return.
   711 
   712 * Case-expressions allow arbitrary constructor-patterns (including "_") and
   713   take their order into account, like in functional programming.
   714   Internally, this is translated into nested case-expressions; missing cases
   715   are added and mapped to the predefined constant "undefined". In complicated
   716   cases printing may no longer show the original input but the internal
   717   form. Lambda-abstractions allow the same form of pattern matching:
   718   "% pat1 => e1 | ..." is an abbreviation for
   719   "%x. case x of pat1 => e1 | ..." where x is a new variable.
   720 
   721 * IntDef: The constant "int :: nat => int" has been removed; now "int"
   722   is an abbreviation for "of_nat :: nat => int". The simplification rules
   723   for "of_nat" have been changed to work like "int" did previously.
   724   (potential INCOMPATIBILITY)
   725   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
   726   - of_nat_diff and of_nat_mult are no longer default simp rules
   727 
   728 * Method "algebra" solves polynomial equations over (semi)rings using
   729   Groebner bases. The (semi)ring structure is defined by locales and
   730   the tool setup depends on that generic context. Installing the
   731   method for a specific type involves instantiating the locale and
   732   possibly adding declarations for computation on the coefficients.
   733   The method is already instantiated for natural numbers and for the
   734   axiomatic class of idoms with numerals.  See also the paper by
   735   Chaieb and Wenzel at CALCULEMUS 2007 for the general principles
   736   underlying this architecture of context-aware proof-tools.
   737 
   738 * constant "List.op @" now named "List.append".  Use ML antiquotations
   739 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   740 possible incompatibilities when working on ML level.
   741 
   742 * Constant renames due to introduction of canonical name prefixing for
   743   class package:
   744 
   745     HOL.abs ~> HOL.minus_class.abs
   746     HOL.divide ~> HOL.divide_class.divide
   747     Nat.power ~> Nat.power_class.power
   748     Nat.size ~> Nat.size_class.size
   749     Numeral.number_of ~> Numeral.number_class.number_of
   750     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   751 
   752 * Rudimentary class target mechanism involves constant renames:
   753 
   754     Orderings.min ~> Orderings.ord_class.min
   755     Orderings.max ~> Orderings.ord_class.max
   756     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   757 
   758 * primrec: missing cases mapped to "undefined" instead of "arbitrary"
   759 
   760 * new constant "undefined" with axiom "undefined x = undefined"
   761 
   762 * new class "default" with associated constant "default"
   763 
   764 * new function listsum :: 'a list => 'a for arbitrary monoids.
   765   Special syntax: "SUM x <- xs. f x" (and latex variants)
   766 
   767 * new (input only) syntax for Haskell-like list comprehension, eg
   768   [(x,y). x <- xs, y <- ys, x ~= y]
   769   For details see List.thy.
   770 
   771 * The special syntax for function "filter" has changed from [x : xs. P] to
   772   [x <- xs. P] to avoid an ambiguity caused by list comprehension syntax,
   773   and for uniformity. INCOMPATIBILITY
   774 
   775 * Lemma "set_take_whileD" renamed to "set_takeWhileD"
   776 
   777 * New lemma collection field_simps (an extension of ring_simps)
   778   for manipulating (in)equations involving division. Multiplies
   779   with all denominators that can be proved to be non-zero (in equations)
   780   or positive/negative (in inequations).
   781 
   782 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
   783   have been improved and renamed to ring_simps, group_simps and ring_distribs.
   784   Removed lemmas field_xyz in Ring_and_Field
   785   because they were subsumed by lemmas xyz.
   786 INCOMPATIBILITY.
   787 
   788 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   789   when generating code.
   790 
   791 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   792   when generating code.
   793 
   794 * Library/Commutative_Ring.thy: switched from recdef to function package;
   795   constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   796 
   797 * Some steps towards more uniform lattice theory development in HOL.
   798 
   799     constants "meet" and "join" now named "inf" and "sup"
   800     constant "Meet" now named "Inf"
   801 
   802     classes "meet_semilorder" and "join_semilorder" now named
   803       "lower_semilattice" and "upper_semilattice"
   804     class "lorder" now named "lattice"
   805     class "comp_lat" now named "complete_lattice"
   806 
   807     Instantiation of lattice classes allows explicit definitions
   808     for "inf" and "sup" operations.
   809 
   810   INCOMPATIBILITY.  Theorem renames:
   811 
   812     meet_left_le            ~> inf_le1
   813     meet_right_le           ~> inf_le2
   814     join_left_le            ~> sup_ge1
   815     join_right_le           ~> sup_ge2
   816     meet_join_le            ~> inf_sup_ord
   817     le_meetI                ~> le_infI
   818     join_leI                ~> le_supI
   819     le_meet                 ~> le_inf_iff
   820     le_join                 ~> ge_sup_conv
   821     meet_idempotent         ~> inf_idem
   822     join_idempotent         ~> sup_idem
   823     meet_comm               ~> inf_commute
   824     join_comm               ~> sup_commute
   825     meet_leI1               ~> le_infI1
   826     meet_leI2               ~> le_infI2
   827     le_joinI1               ~> le_supI1
   828     le_joinI2               ~> le_supI2
   829     meet_assoc              ~> inf_assoc
   830     join_assoc              ~> sup_assoc
   831     meet_left_comm          ~> inf_left_commute
   832     meet_left_idempotent    ~> inf_left_idem
   833     join_left_comm          ~> sup_left_commute
   834     join_left_idempotent    ~> sup_left_idem
   835     meet_aci                ~> inf_aci
   836     join_aci                ~> sup_aci
   837     le_def_meet             ~> le_iff_inf
   838     le_def_join             ~> le_iff_sup
   839     join_absorp2            ~> sup_absorb2
   840     join_absorp1            ~> sup_absorb1
   841     meet_absorp1            ~> inf_absorb1
   842     meet_absorp2            ~> inf_absorb2
   843     meet_join_absorp        ~> inf_sup_absorb
   844     join_meet_absorp        ~> sup_inf_absorb
   845     distrib_join_le         ~> distrib_sup_le
   846     distrib_meet_le         ~> distrib_inf_le
   847 
   848     add_meet_distrib_left   ~> add_inf_distrib_left
   849     add_join_distrib_left   ~> add_sup_distrib_left
   850     is_join_neg_meet        ~> is_join_neg_inf
   851     is_meet_neg_join        ~> is_meet_neg_sup
   852     add_meet_distrib_right  ~> add_inf_distrib_right
   853     add_join_distrib_right  ~> add_sup_distrib_right
   854     add_meet_join_distribs  ~> add_sup_inf_distribs
   855     join_eq_neg_meet        ~> sup_eq_neg_inf
   856     meet_eq_neg_join        ~> inf_eq_neg_sup
   857     add_eq_meet_join        ~> add_eq_inf_sup
   858     meet_0_imp_0            ~> inf_0_imp_0
   859     join_0_imp_0            ~> sup_0_imp_0
   860     meet_0_eq_0             ~> inf_0_eq_0
   861     join_0_eq_0             ~> sup_0_eq_0
   862     neg_meet_eq_join        ~> neg_inf_eq_sup
   863     neg_join_eq_meet        ~> neg_sup_eq_inf
   864     join_eq_if              ~> sup_eq_if
   865 
   866     mono_meet               ~> mono_inf
   867     mono_join               ~> mono_sup
   868     meet_bool_eq            ~> inf_bool_eq
   869     join_bool_eq            ~> sup_bool_eq
   870     meet_fun_eq             ~> inf_fun_eq
   871     join_fun_eq             ~> sup_fun_eq
   872     meet_set_eq             ~> inf_set_eq
   873     join_set_eq             ~> sup_set_eq
   874     meet1_iff               ~> inf1_iff
   875     meet2_iff               ~> inf2_iff
   876     meet1I                  ~> inf1I
   877     meet2I                  ~> inf2I
   878     meet1D1                 ~> inf1D1
   879     meet2D1                 ~> inf2D1
   880     meet1D2                 ~> inf1D2
   881     meet2D2                 ~> inf2D2
   882     meet1E                  ~> inf1E
   883     meet2E                  ~> inf2E
   884     join1_iff               ~> sup1_iff
   885     join2_iff               ~> sup2_iff
   886     join1I1                 ~> sup1I1
   887     join2I1                 ~> sup2I1
   888     join1I1                 ~> sup1I1
   889     join2I2                 ~> sup1I2
   890     join1CI                 ~> sup1CI
   891     join2CI                 ~> sup2CI
   892     join1E                  ~> sup1E
   893     join2E                  ~> sup2E
   894 
   895     is_meet_Meet            ~> is_meet_Inf
   896     Meet_bool_def           ~> Inf_bool_def
   897     Meet_fun_def            ~> Inf_fun_def
   898     Meet_greatest           ~> Inf_greatest
   899     Meet_lower              ~> Inf_lower
   900     Meet_set_def            ~> Inf_set_def
   901 
   902     listsp_meetI            ~> listsp_infI
   903     listsp_meet_eq          ~> listsp_inf_eq
   904 
   905     meet_min                ~> inf_min
   906     join_max                ~> sup_max
   907 
   908 * Classes "order" and "linorder": facts "refl", "trans" and
   909 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   910 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   911 
   912 * Classes "order" and "linorder": 
   913 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   914 proofs changed.
   915 
   916 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   917 INCOMPATIBILITY.
   918 
   919 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   920 INCOMPATIBILITY.
   921 
   922 * Added syntactic class "size"; overloaded constant "size" now has
   923 type "'a::size ==> bool"
   924 
   925 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   926 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   927 
   928 * Added method "lexicographic_order" automatically synthesizes
   929 termination relations as lexicographic combinations of size measures
   930 -- 'function' package.
   931 
   932 * HOL/records: generalised field-update to take a function on the
   933 field rather than the new value: r(|A := x|) is translated to A_update
   934 (K x) r The K-combinator that is internally used is called K_record.
   935 INCOMPATIBILITY: Usage of the plain update functions has to be
   936 adapted.
   937  
   938 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   939 0 * x = 0, which are required for a semiring.  Richer structures do
   940 not inherit from semiring_0 anymore, because this property is a
   941 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   942 semiring_0, there is more to prove, but this is mostly trivial.
   943 
   944 * axclass "recpower" was generalized to arbitrary monoids, not just
   945 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   946 commutativity or a semiring property, add the corresponding classes.
   947 
   948 * Unified locale partial_order with class definition (cf. theory
   949 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   950 
   951 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   952 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   953 Isar level, use abbreviations instead.
   954 
   955 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   956 rarely occuring name references (e.g. ``List.op mem.simps'') require
   957 renaming (e.g. ``List.memberl.simps'').
   958 
   959 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   960 INCOMPATIBILITY.
   961 
   962 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
   963 
   964 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   965 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   966 significant changes for setting up numeral syntax for types:
   967 
   968   - new constants Numeral.pred and Numeral.succ instead
   969       of former Numeral.bin_pred and Numeral.bin_succ.
   970   - Use integer operations instead of bin_add, bin_mult and so on.
   971   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   972   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   973 
   974 See HOL/Integ/IntArith.thy for an example setup.
   975 
   976 * New top level command 'normal_form' computes the normal form of a
   977 term that may contain free variables. For example ``normal_form
   978 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   979 suitable for heavy-duty computations because the functions are
   980 compiled to ML first.
   981 
   982 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   983 25 like -->); output depends on the "iff" print_mode, the default is
   984 "A = B" (with priority 50).
   985 
   986 * Renamed constants in HOL.thy and Orderings.thy:
   987     op +   ~> HOL.plus_class.plus
   988     op -   ~> HOL.minus_class.minus
   989     uminus ~> HOL.minus_class.uminus
   990     abs    ~> HOL.abs_class.abs
   991     op *   ~> HOL.times_class.times
   992     op <   ~> HOL.ord_class.less
   993     op <=  ~> HOL.ord_class.less_eq
   994 
   995 Adaptions may be required in the following cases:
   996 
   997 a) User-defined constants using any of the names "plus", "minus", "times",
   998 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   999 may go wrong.
  1000 INCOMPATIBILITY: use more specific names.
  1001 
  1002 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1003 INCOMPATIBILITY: use more specific names.
  1004 
  1005 c) Permutative equations (e.g. "a + b = b + a")
  1006 Since the change of names also changes the order of terms, permutative
  1007 rewrite rules may get applied in a different order. Experience shows that
  1008 this is rarely the case (only two adaptions in the whole Isabelle
  1009 distribution).
  1010 INCOMPATIBILITY: rewrite proofs
  1011 
  1012 d) ML code directly refering to constant names
  1013 This in general only affects hand-written proof tactics, simprocs and so on.
  1014 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
  1015 of const_name ML antiquotations.
  1016 
  1017 * Relations less (<) and less_eq (<=) are also available on type bool.
  1018 Modified syntax to disallow nesting without explicit parentheses,
  1019 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
  1020 
  1021 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1022 
  1023 * Relation composition operator "op O" now has precedence 75 and binds
  1024 stronger than union and intersection. INCOMPATIBILITY.
  1025 
  1026 * The old set interval syntax "{m..n(}" (and relatives) has been
  1027 removed.  Use "{m..<n}" (and relatives) instead.
  1028 
  1029 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1030 "t = s" to False (by simproc "neq_simproc").  For backward
  1031 compatibility this can be disabled by ML "reset use_neq_simproc".
  1032 
  1033 * "m dvd n" where m and n are numbers is evaluated to True/False by
  1034 simp.
  1035 
  1036 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
  1037 
  1038 * Theorem setsum_mult renamed to setsum_right_distrib.
  1039 
  1040 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1041 ``rule'' method.
  1042 
  1043 * Reimplemented methods ``sat'' and ``satx'', with several
  1044 improvements: goals no longer need to be stated as "<prems> ==>
  1045 False", equivalences (i.e. "=" on type bool) are handled, variable
  1046 names of the form "lit_<n>" are no longer reserved, significant
  1047 speedup.
  1048 
  1049 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
  1050 zChaff is still supported as well.
  1051 
  1052 * 'inductive' and 'datatype': provide projections of mutual rules,
  1053 bundled as foo_bar.inducts;
  1054 
  1055 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1056 Library.
  1057 
  1058 * Library: moved theory Accessible_Part to main HOL.
  1059 
  1060 * Library: added theory Coinductive_List of potentially infinite lists
  1061 as greatest fixed-point.
  1062 
  1063 * Library: added theory AssocList which implements (finite) maps as
  1064 association lists.
  1065 
  1066 * Added proof method ``evaluation'' for efficiently solving a goal
  1067 (i.e. a boolean expression) by compiling it to ML. The goal is
  1068 "proved" (via an oracle) if it evaluates to True.
  1069 
  1070 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1071 also when invoked by the simplifier.  This results in the simplifier
  1072 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
  1073 fast_arith_split_limit to 0 to obtain the old behavior.
  1074 
  1075 * Support for hex (0x20) and binary (0b1001) numerals.
  1076 
  1077 * New method: reify eqs (t), where eqs are equations for an
  1078 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1079 parameter, computes a term s::'b and a list xs::'a list and proves the
  1080 theorem I xs s = t. This is also known as reification or quoting. The
  1081 resulting theorem is applied to the subgoal to substitute t with I xs
  1082 s.  If t is omitted, the subgoal itself is reified.
  1083 
  1084 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1085 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1086 where f is supposed to be a computable function (in the sense of code
  1087 generattion). The method uses reify to compute s and xs as above then
  1088 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1089 r and finally gets the theorem t = r, which is again applied to the
  1090 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
  1091 
  1092 * Reflection: Automatic reification now handels binding, an example
  1093 is available in HOL/ex/ReflectionEx.thy
  1094 
  1095 
  1096 *** HOL-Algebra ***
  1097 
  1098 * Formalisation of ideals and the quotient construction over rings.
  1099 
  1100 * Order and lattice theory no longer based on records.
  1101 INCOMPATIBILITY.
  1102 
  1103 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1104 greatest_closed.  INCOMPATIBILITY.
  1105 
  1106 * Method algebra is now set up via an attribute.  For examples see
  1107 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1108 of algebraic structures.
  1109 
  1110 * Renamed theory CRing to Ring.
  1111 
  1112 
  1113 *** HOL-Complex ***
  1114 
  1115 * Theory Real: new method ferrack implements quantifier elimination
  1116 for linear arithmetic over the reals. The quantifier elimination
  1117 feature is used only for decision, for compatibility with arith. This
  1118 means a goal is either solved or left unchanged, no simplification.
  1119 
  1120 * Hyperreal: Functions root and sqrt are now defined on negative real
  1121 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1122 Nonnegativity side conditions have been removed from many lemmas, so
  1123 that more subgoals may now be solved by simplification; potential
  1124 INCOMPATIBILITY.
  1125 
  1126 * Real: New axiomatic classes formalize real normed vector spaces and
  1127 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1128 and norm :: 'a => real.
  1129 
  1130 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
  1131 from reals into other types. The overloaded constant Reals :: 'a set
  1132 is now defined as range of_real; potential INCOMPATIBILITY.
  1133 
  1134 * Real: ML code generation is supported now and hence also quickcheck.
  1135 Reals are implemented as arbitrary precision rationals.
  1136 
  1137 * Hyperreal: Several constants that previously worked only for the
  1138 reals have been generalized, so they now work over arbitrary vector
  1139 spaces. Type annotations may need to be added in some cases; potential
  1140 INCOMPATIBILITY.
  1141 
  1142   Infinitesimal  :: ('a::real_normed_vector) star set
  1143   HFinite        :: ('a::real_normed_vector) star set
  1144   HInfinite      :: ('a::real_normed_vector) star set
  1145   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1146   monad          :: ('a::real_normed_vector) star => 'a star set
  1147   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1148   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1149   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1150   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1151   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1152   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1153   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1154   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1155   sgn            :: 'a::real_normed_vector => 'a
  1156   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1157 
  1158 * Complex: Some complex-specific constants are now abbreviations for
  1159 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1160 hnorm.  Other constants have been entirely removed in favor of the
  1161 polymorphic versions (INCOMPATIBILITY):
  1162 
  1163   approx        <-- capprox
  1164   HFinite       <-- CFinite
  1165   HInfinite     <-- CInfinite
  1166   Infinitesimal <-- CInfinitesimal
  1167   monad         <-- cmonad
  1168   galaxy        <-- cgalaxy
  1169   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1170   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1171   (ns)deriv     <-- (ns)cderiv
  1172 
  1173 
  1174 *** ML ***
  1175 
  1176 * Generic arithmetic modules: Tools/integer.ML, Tools/rat.ML, Tools/float.ML
  1177 
  1178 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1179 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1180 init only required for impure data.  INCOMPATIBILITY: empty really
  1181 need to be empty (no dependencies on theory content!)
  1182 
  1183 * ML within Isar: antiquotations allow to embed statically-checked
  1184 formal entities in the source, referring to the context available at
  1185 compile-time.  For example:
  1186 
  1187 ML {* @{typ "'a => 'b"} *}
  1188 ML {* @{term "%x. x"} *}
  1189 ML {* @{prop "x == y"} *}
  1190 ML {* @{ctyp "'a => 'b"} *}
  1191 ML {* @{cterm "%x. x"} *}
  1192 ML {* @{cprop "x == y"} *}
  1193 ML {* @{thm asm_rl} *}
  1194 ML {* @{thms asm_rl} *}
  1195 ML {* @{const_name c} *}
  1196 ML {* @{const_syntax c} *}
  1197 ML {* @{context} *}
  1198 ML {* @{theory} *}
  1199 ML {* @{theory Pure} *}
  1200 ML {* @{simpset} *}
  1201 ML {* @{claset} *}
  1202 ML {* @{clasimpset} *}
  1203 
  1204 The same works for sources being ``used'' within an Isar context.
  1205 
  1206 * ML in Isar: improved error reporting; extra verbosity with
  1207 Toplevel.debug enabled.
  1208 
  1209 * Pure/library:
  1210 
  1211   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1212   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1213 
  1214 The semantics of "burrow" is: "take a function with *simulatanously*
  1215 transforms a list of value, and apply it *simulatanously* to a list of
  1216 list of values of the appropriate type". Compare this with "map" which
  1217 would *not* apply its argument function simulatanously but in
  1218 sequence; "fold_burrow" has an additional context.
  1219 
  1220 * Pure/library: functions map2 and fold2 with curried syntax for
  1221 simultanous mapping and folding:
  1222 
  1223     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1224     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1225 
  1226 * Pure/library: indexed lists - some functions in the Isabelle library
  1227 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1228 given more convenient names and signatures reminiscent of similar
  1229 functions for alists, tables, etc:
  1230 
  1231   val nth: 'a list -> int -> 'a 
  1232   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1233   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1234 
  1235 Note that fold_index starts counting at index 0, not 1 like foldln
  1236 used to.
  1237 
  1238 * Pure/library: added general ``divide_and_conquer'' combinator on
  1239 lists.
  1240 
  1241 * Pure/General/table.ML: the join operations now works via exceptions
  1242 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1243 admits slightly more efficient complex applications.
  1244 
  1245 * Pure: datatype Context.generic joins theory/Proof.context and
  1246 provides some facilities for code that works in either kind of
  1247 context, notably GenericDataFun for uniform theory and proof data.
  1248 
  1249 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1250 use Context.generic instead of just theory.
  1251 
  1252 * Pure: simplified internal attribute type, which is now always
  1253 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1254 vs. local (Proof.context) attributes have been discontinued, while
  1255 minimizing code duplication.  Thm.rule_attribute and
  1256 Thm.declaration_attribute build canonical attributes; see also
  1257 structure Context for further operations on Context.generic, notably
  1258 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1259 declarations and definitions.
  1260 
  1261 * Pure/kernel: consts certification ignores sort constraints given in
  1262 signature declarations.  (This information is not relevant to the
  1263 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1264 potential INCOMPATIBILITY.
  1265 
  1266 * Pure: axiomatic type classes are now purely definitional, with
  1267 explicit proofs of class axioms and super class relations performed
  1268 internally.  See Pure/axclass.ML for the main internal interfaces --
  1269 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1270 AxClass.axiomatize_class/classrel/arity supercede
  1271 Sign.add_classes/classrel/arities.
  1272 
  1273 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1274 global/local versions on theory vs. Proof.context have been
  1275 discontinued; Attrib.syntax and Method.syntax have been adapted
  1276 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1277 attributes, methods, etc.
  1278 
  1279 * Pure: several functions of signature "... -> theory -> theory * ..."
  1280 have been reoriented to "... -> theory -> ... * theory" in order to
  1281 allow natural usage in combination with the ||>, ||>>, |-> and
  1282 fold_map combinators.
  1283 
  1284 * Pure: official theorem names (closed derivations) and additional
  1285 comments (tags) are now strictly separate.  Name hints -- which are
  1286 maintained as tags -- may be attached any time without affecting the
  1287 derivation.
  1288 
  1289 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1290 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1291 achieve the old behaviour.
  1292 
  1293 * Pure: the "Goal" constant is now called "prop", supporting a
  1294 slightly more general idea of ``protecting'' meta-level rule
  1295 statements.
  1296 
  1297 * Pure: Logic.(un)varify only works in a global context, which is now
  1298 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1299 Logic.legacy_(un)varify as temporary workaround.
  1300 
  1301 * Pure: structure Name provides scalable operations for generating
  1302 internal variable names, notably Name.variants etc.  This replaces
  1303 some popular functions from term.ML:
  1304 
  1305   Term.variant		->  Name.variant
  1306   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1307   Term.invent_names	->  Name.invent_list
  1308 
  1309 Note that low-level renaming rarely occurs in new code -- operations
  1310 from structure Variable are used instead (see below).
  1311 
  1312 * Pure: structure Variable provides fundamental operations for proper
  1313 treatment of fixed/schematic variables in a context.  For example,
  1314 Variable.import introduces fixes for schematics of given facts and
  1315 Variable.export reverses the effect (up to renaming) -- this replaces
  1316 various freeze_thaw operations.
  1317 
  1318 * Pure: structure Goal provides simple interfaces for
  1319 init/conclude/finish and tactical prove operations (replacing former
  1320 Tactic.prove).  Goal.prove is the canonical way to prove results
  1321 within a given context; Goal.prove_global is a degraded version for
  1322 theory level goals, including a global Drule.standard.  Note that
  1323 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1324 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1325 in a locale context).
  1326 
  1327 * Isar: simplified treatment of user-level errors, using exception
  1328 ERROR of string uniformly.  Function error now merely raises ERROR,
  1329 without any side effect on output channels.  The Isar toplevel takes
  1330 care of proper display of ERROR exceptions.  ML code may use plain
  1331 handle/can/try; cat_error may be used to concatenate errors like this:
  1332 
  1333   ... handle ERROR msg => cat_error msg "..."
  1334 
  1335 Toplevel ML code (run directly or through the Isar toplevel) may be
  1336 embedded into the Isar toplevel with exception display/debug like
  1337 this:
  1338 
  1339   Isar.toplevel (fn () => ...)
  1340 
  1341 INCOMPATIBILITY, removed special transform_error facilities, removed
  1342 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1343 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1344 -- use plain ERROR instead.
  1345 
  1346 * Isar: theory setup now has type (theory -> theory), instead of a
  1347 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1348 
  1349 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1350 subject to ProofContext.debug/verbose flags.
  1351 
  1352 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1353 theory before entering a proof state.  Transactions now always see a
  1354 quasi-functional intermediate checkpoint, both in interactive and
  1355 batch mode.
  1356 
  1357 * Simplifier: the simpset of a running simplification process now
  1358 contains a proof context (cf. Simplifier.the_context), which is the
  1359 very context that the initial simpset has been retrieved from (by
  1360 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1361 (solver, looper etc.) may depend on arbitrary proof data.
  1362 
  1363 * Simplifier.inherit_context inherits the proof context (plus the
  1364 local bounds) of the current simplification process; any simproc
  1365 etc. that calls the Simplifier recursively should do this!  Removed
  1366 former Simplifier.inherit_bounds, which is already included here --
  1367 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1368 specify an explicit context using Simplifier.context/theory_context.
  1369 
  1370 * Simplifier/Classical Reasoner: more abstract interfaces
  1371 change_simpset/claset for modifying the simpset/claset reference of a
  1372 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1373 INCOMPATIBILITY.
  1374 
  1375 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1376 "Trueprop" etc.
  1377 
  1378 
  1379 *** System ***
  1380 
  1381 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1382 locations -- now includes the Isabelle version identifier as well.
  1383 This simplifies use of multiple Isabelle installations.
  1384 
  1385 * isabelle-process: option -S (secure mode) disables some critical
  1386 operations, notably runtime compilation and evaluation of ML source
  1387 code.
  1388 
  1389 
  1390 New in Isabelle2005 (October 2005)
  1391 ----------------------------------
  1392 
  1393 *** General ***
  1394 
  1395 * Theory headers: the new header syntax for Isar theories is
  1396 
  1397   theory <name>
  1398   imports <theory1> ... <theoryN>
  1399   uses <file1> ... <fileM>
  1400   begin
  1401 
  1402 where the 'uses' part is optional.  The previous syntax
  1403 
  1404   theory <name> = <theory1> + ... + <theoryN>:
  1405 
  1406 will disappear in the next release.  Use isatool fixheaders to convert
  1407 existing theory files.  Note that there is no change in ancient
  1408 non-Isar theories now, but these will disappear soon.
  1409 
  1410 * Theory loader: parent theories can now also be referred to via
  1411 relative and absolute paths.
  1412 
  1413 * Command 'find_theorems' searches for a list of criteria instead of a
  1414 list of constants. Known criteria are: intro, elim, dest, name:string,
  1415 simp:term, and any term. Criteria can be preceded by '-' to select
  1416 theorems that do not match. Intro, elim, dest select theorems that
  1417 match the current goal, name:s selects theorems whose fully qualified
  1418 name contain s, and simp:term selects all simplification rules whose
  1419 lhs match term.  Any other term is interpreted as pattern and selects
  1420 all theorems matching the pattern. Available in ProofGeneral under
  1421 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1422 
  1423   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1424 
  1425 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1426 matching the current goal as introduction rule and not having "HOL."
  1427 in their name (i.e. not being defined in theory HOL).
  1428 
  1429 * Command 'thms_containing' has been discontinued in favour of
  1430 'find_theorems'; INCOMPATIBILITY.
  1431 
  1432 * Communication with Proof General is now 8bit clean, which means that
  1433 Unicode text in UTF-8 encoding may be used within theory texts (both
  1434 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1435 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1436 
  1437   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1438   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1439 
  1440 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1441 Classical Reasoner.  Typical big applications run around 2 times
  1442 faster.
  1443 
  1444 
  1445 *** Document preparation ***
  1446 
  1447 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1448 of raw sources.  Only those symbols that do not require additional
  1449 LaTeX packages (depending on comments in isabellesym.sty) are
  1450 displayed properly, everything else is left verbatim.  isatool display
  1451 and isatool print are used as front ends (these are subject to the
  1452 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1453 
  1454 * Command tags control specific markup of certain regions of text,
  1455 notably folding and hiding.  Predefined tags include "theory" (for
  1456 theory begin and end), "proof" for proof commands, and "ML" for
  1457 commands involving ML code; the additional tags "visible" and
  1458 "invisible" are unused by default.  Users may give explicit tag
  1459 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1460 interpretation of tags is determined by the LaTeX job during document
  1461 preparation: see option -V of isatool usedir, or options -n and -t of
  1462 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1463 \isadroptag.
  1464 
  1465 Several document versions may be produced at the same time via isatool
  1466 usedir (the generated index.html will link all of them).  Typical
  1467 specifications include ''-V document=theory,proof,ML'' to present
  1468 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1469 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1470 these parts without any formal replacement text.  The Isabelle site
  1471 default settings produce ''document'' and ''outline'' versions as
  1472 specified above.
  1473 
  1474 * Several new antiquotations:
  1475 
  1476   @{term_type term} prints a term with its type annotated;
  1477 
  1478   @{typeof term} prints the type of a term;
  1479 
  1480   @{const const} is the same as @{term const}, but checks that the
  1481   argument is a known logical constant;
  1482 
  1483   @{term_style style term} and @{thm_style style thm} print a term or
  1484   theorem applying a "style" to it
  1485 
  1486   @{ML text}
  1487 
  1488 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1489 definitions, equations, inequations etc., 'concl' printing only the
  1490 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1491 to print the specified premise.  TermStyle.add_style provides an ML
  1492 interface for introducing further styles.  See also the "LaTeX Sugar"
  1493 document practical applications.  The ML antiquotation prints
  1494 type-checked ML expressions verbatim.
  1495 
  1496 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1497 and 'text' support optional locale specification '(in loc)', which
  1498 specifies the default context for interpreting antiquotations.  For
  1499 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1500 
  1501 * Option 'locale=NAME' of antiquotations specifies an alternative
  1502 context interpreting the subsequent argument.  For example: @{thm
  1503 [locale=lattice] inf_assoc}.
  1504 
  1505 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1506 a proof context.
  1507 
  1508 * Proper output of antiquotations for theory commands involving a
  1509 proof context (such as 'locale' or 'theorem (in loc) ...').
  1510 
  1511 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1512 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1513 
  1514 * isatool usedir: new option -C (default true) controls whether option
  1515 -D should include a copy of the original document directory; -C false
  1516 prevents unwanted effects such as copying of administrative CVS data.
  1517 
  1518 
  1519 *** Pure ***
  1520 
  1521 * Considerably improved version of 'constdefs' command.  Now performs
  1522 automatic type-inference of declared constants; additional support for
  1523 local structure declarations (cf. locales and HOL records), see also
  1524 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1525 sequential dependencies of definitions within a single 'constdefs'
  1526 section; moreover, the declared name needs to be an identifier.  If
  1527 all fails, consider to fall back on 'consts' and 'defs' separately.
  1528 
  1529 * Improved indexed syntax and implicit structures.  First of all,
  1530 indexed syntax provides a notational device for subscripted
  1531 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1532 expressions.  Secondly, in a local context with structure
  1533 declarations, number indexes \<^sub>n or the empty index (default
  1534 number 1) refer to a certain fixed variable implicitly; option
  1535 show_structs controls printing of implicit structures.  Typical
  1536 applications of these concepts involve record types and locales.
  1537 
  1538 * New command 'no_syntax' removes grammar declarations (and
  1539 translations) resulting from the given syntax specification, which is
  1540 interpreted in the same manner as for the 'syntax' command.
  1541 
  1542 * 'Advanced' translation functions (parse_translation etc.) may depend
  1543 on the signature of the theory context being presently used for
  1544 parsing/printing, see also isar-ref manual.
  1545 
  1546 * Improved 'oracle' command provides a type-safe interface to turn an
  1547 ML expression of type theory -> T -> term into a primitive rule of
  1548 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1549 is already included here); see also FOL/ex/IffExample.thy;
  1550 INCOMPATIBILITY.
  1551 
  1552 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1553 before); "cI" is no longer bound, use "c.intro" instead.
  1554 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1555 axclasses vs. locales.
  1556 
  1557 * Improved internal renaming of symbolic identifiers -- attach primes
  1558 instead of base 26 numbers.
  1559 
  1560 * New flag show_question_marks controls printing of leading question
  1561 marks in schematic variable names.
  1562 
  1563 * In schematic variable names, *any* symbol following \<^isub> or
  1564 \<^isup> is now treated as part of the base name.  For example, the
  1565 following works without printing of awkward ".0" indexes:
  1566 
  1567   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1568     by simp
  1569 
  1570 * Inner syntax includes (*(*nested*) comments*).
  1571 
  1572 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1573 annotations as "(00...)".
  1574 
  1575 * Clear separation of logical types and nonterminals, where the latter
  1576 may only occur in 'syntax' specifications or type abbreviations.
  1577 Before that distinction was only partially implemented via type class
  1578 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1579 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1580 exotic syntax specifications may require further adaption
  1581 (e.g. Cube/Cube.thy).
  1582 
  1583 * Removed obsolete type class "logic", use the top sort {} instead.
  1584 Note that non-logical types should be declared as 'nonterminals'
  1585 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1586 specifications.
  1587 
  1588 * Attributes 'induct' and 'cases': type or set names may now be
  1589 locally fixed variables as well.
  1590 
  1591 * Simplifier: can now control the depth to which conditional rewriting
  1592 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1593 Limit.
  1594 
  1595 * Simplifier: simplification procedures may now take the current
  1596 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1597 interface), which is very useful for calling the Simplifier
  1598 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1599 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1600 low-level mk_simproc no longer applies Logic.varify internally, to
  1601 allow for use in a context of fixed variables.
  1602 
  1603 * thin_tac now works even if the assumption being deleted contains !!
  1604 or ==>.  More generally, erule now works even if the major premise of
  1605 the elimination rule contains !! or ==>.
  1606 
  1607 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1608 
  1609 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1610 from Pure, which contains all common declarations already.  Both
  1611 theories are defined via plain Isabelle/Isar .thy files.
  1612 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1613 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1614 use isatool fixcpure to adapt your theory and ML sources.
  1615 
  1616 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1617 selections of theorems in named facts via index ranges.
  1618 
  1619 * 'print_theorems': in theory mode, really print the difference
  1620 wrt. the last state (works for interactive theory development only),
  1621 in proof mode print all local facts (cf. 'print_facts');
  1622 
  1623 * 'hide': option '(open)' hides only base names.
  1624 
  1625 * More efficient treatment of intermediate checkpoints in interactive
  1626 theory development.
  1627 
  1628 * Code generator is now invoked via code_module (incremental code
  1629 generation) and code_library (modular code generation, ML structures
  1630 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1631 must be quoted when used as identifiers.
  1632 
  1633 * New 'value' command for reading, evaluating and printing terms using
  1634 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1635 quoted when used as identifier.
  1636 
  1637 
  1638 *** Locales ***
  1639 
  1640 * New commands for the interpretation of locale expressions in
  1641 theories (1), locales (2) and proof contexts (3).  These generate
  1642 proof obligations from the expression specification.  After the
  1643 obligations have been discharged, theorems of the expression are added
  1644 to the theory, target locale or proof context.  The synopsis of the
  1645 commands is a follows:
  1646 
  1647   (1) interpretation expr inst
  1648   (2) interpretation target < expr
  1649   (3) interpret expr inst
  1650 
  1651 Interpretation in theories and proof contexts require a parameter
  1652 instantiation of terms from the current context.  This is applied to
  1653 specifications and theorems of the interpreted expression.
  1654 Interpretation in locales only permits parameter renaming through the
  1655 locale expression.  Interpretation is smart in that interpretations
  1656 that are active already do not occur in proof obligations, neither are
  1657 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1658 inspect active interpretations of a particular locale.  For details,
  1659 see the Isar Reference manual.  Examples can be found in
  1660 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1661 
  1662 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1663 'interpret' instead.
  1664 
  1665 * New context element 'constrains' for adding type constraints to
  1666 parameters.
  1667 
  1668 * Context expressions: renaming of parameters with syntax
  1669 redeclaration.
  1670 
  1671 * Locale declaration: 'includes' disallowed.
  1672 
  1673 * Proper static binding of attribute syntax -- i.e. types / terms /
  1674 facts mentioned as arguments are always those of the locale definition
  1675 context, independently of the context of later invocations.  Moreover,
  1676 locale operations (renaming and type / term instantiation) are applied
  1677 to attribute arguments as expected.
  1678 
  1679 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1680 actual attributes; rare situations may require Attrib.attribute to
  1681 embed those attributes into Attrib.src that lack concrete syntax.
  1682 Attribute implementations need to cooperate properly with the static
  1683 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1684 Attrib.XXX_thm etc. already do the right thing without further
  1685 intervention.  Only unusual applications -- such as "where" or "of"
  1686 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1687 on the context and the facts involved -- may have to assign parsed
  1688 values to argument tokens explicitly.
  1689 
  1690 * Changed parameter management in theorem generation for long goal
  1691 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1692 theorem statement in rare situations.
  1693 
  1694 * Locale inspection command 'print_locale' omits notes elements.  Use
  1695 'print_locale!' to have them included in the output.
  1696 
  1697 
  1698 *** Provers ***
  1699 
  1700 * Provers/hypsubst.ML: improved version of the subst method, for
  1701 single-step rewriting: it now works in bound variable contexts. New is
  1702 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1703 rewrite a different subterm than the original subst method, which is
  1704 still available as 'simplesubst'.
  1705 
  1706 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1707 and quasi orders.
  1708 
  1709 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1710 reflexive-transitive closure of relations.
  1711 
  1712 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1713 limit (previously hard-coded with a value of 20) user-definable.
  1714 
  1715 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1716 is peformed already.  Object-logics merely need to finish their
  1717 initial simpset configuration as before.  INCOMPATIBILITY.
  1718 
  1719 
  1720 *** HOL ***
  1721 
  1722 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1723 
  1724   syntax (epsilon)
  1725     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1726 
  1727 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1728 and x-symbol; use option '-m epsilon' to get it actually printed.
  1729 Moreover, the mathematically important symbolic identifier \<epsilon>
  1730 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1731 
  1732 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1733 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1734 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1735 support corresponding Isar calculations.
  1736 
  1737 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1738 instead of ":".
  1739 
  1740 * theory SetInterval: changed the syntax for open intervals:
  1741 
  1742   Old       New
  1743   {..n(}    {..<n}
  1744   {)n..}    {n<..}
  1745   {m..n(}   {m..<n}
  1746   {)m..n}   {m<..n}
  1747   {)m..n(}  {m<..<n}
  1748 
  1749 The old syntax is still supported but will disappear in the next
  1750 release.  For conversion use the following Emacs search and replace
  1751 patterns (these are not perfect but work quite well):
  1752 
  1753   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1754   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1755 
  1756 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1757 equalities in commutative rings; method 'algebra' provides a generic
  1758 interface.
  1759 
  1760 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1761 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1762 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1763 be a tuple pattern.
  1764 
  1765 Some new syntax forms are available:
  1766 
  1767   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1768   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1769   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1770   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1771 
  1772 The latter form "\<Sum>x < k. e" used to be based on a separate
  1773 function "Summation", which has been discontinued.
  1774 
  1775 * theory Finite_Set: in structured induction proofs, the insert case
  1776 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1777 (insert F x)'.
  1778 
  1779 * The 'refute' command has been extended to support a much larger
  1780 fragment of HOL, including axiomatic type classes, constdefs and
  1781 typedefs, inductive datatypes and recursion.
  1782 
  1783 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1784 Requires zChaff with proof generation to be installed.  See
  1785 HOL/ex/SAT_Examples.thy for examples.
  1786 
  1787 * Datatype induction via method 'induct' now preserves the name of the
  1788 induction variable. For example, when proving P(xs::'a list) by
  1789 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1790 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1791 in unstructured proof scripts.
  1792 
  1793 * Reworked implementation of records.  Improved scalability for
  1794 records with many fields, avoiding performance problems for type
  1795 inference. Records are no longer composed of nested field types, but
  1796 of nested extension types. Therefore the record type only grows linear
  1797 in the number of extensions and not in the number of fields.  The
  1798 top-level (users) view on records is preserved.  Potential
  1799 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1800 old record representation. The type generated for a record is called
  1801 <record_name>_ext_type.
  1802 
  1803 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1804 proofs triggered by a record definition or a simproc (if
  1805 quick_and_dirty is enabled).  Definitions of large records can take
  1806 quite long.
  1807 
  1808 New simproc record_upd_simproc for simplification of multiple record
  1809 updates enabled by default.  Moreover, trivial updates are also
  1810 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1811 occasionally, since simplification is more powerful by default.
  1812 
  1813 * typedef: proper support for polymorphic sets, which contain extra
  1814 type-variables in the term.
  1815 
  1816 * Simplifier: automatically reasons about transitivity chains
  1817 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1818 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1819 old proofs break occasionally as simplification may now solve more
  1820 goals than previously.
  1821 
  1822 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1823 present.  Works for all partial orders (class "order"), in particular
  1824 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1825 just like y <= x.
  1826 
  1827 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1828 bound variable or a constant then the let is unfolded.  Otherwise
  1829 first a is simplified to b, and then f b is simplified to g. If
  1830 possible we abstract b from g arriving at "let x = b in h x",
  1831 otherwise we unfold the let and arrive at g.  The simproc can be
  1832 enabled/disabled by the reference use_let_simproc.  Potential
  1833 INCOMPATIBILITY since simplification is more powerful by default.
  1834 
  1835 * Classical reasoning: the meson method now accepts theorems as arguments.
  1836 
  1837 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1838 jobs to provide advice on the provability of subgoals.
  1839 
  1840 * Theory OrderedGroup and Ring_and_Field: various additions and
  1841 improvements to faciliate calculations involving equalities and
  1842 inequalities.
  1843 
  1844 The following theorems have been eliminated or modified
  1845 (INCOMPATIBILITY):
  1846 
  1847   abs_eq             now named abs_of_nonneg
  1848   abs_of_ge_0        now named abs_of_nonneg
  1849   abs_minus_eq       now named abs_of_nonpos
  1850   imp_abs_id         now named abs_of_nonneg
  1851   imp_abs_neg_id     now named abs_of_nonpos
  1852   mult_pos           now named mult_pos_pos
  1853   mult_pos_le        now named mult_nonneg_nonneg
  1854   mult_pos_neg_le    now named mult_nonneg_nonpos
  1855   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1856   mult_neg           now named mult_neg_neg
  1857   mult_neg_le        now named mult_nonpos_nonpos
  1858 
  1859 * The following lemmas in Ring_and_Field have been added to the simplifier:
  1860      
  1861      zero_le_square
  1862      not_square_less_zero 
  1863 
  1864   The following lemmas have been deleted from Real/RealPow:
  1865   
  1866      realpow_zero_zero
  1867      realpow_two
  1868      realpow_less
  1869      zero_le_power
  1870      realpow_two_le
  1871      abs_realpow_two
  1872      realpow_two_abs     
  1873 
  1874 * Theory Parity: added rules for simplifying exponents.
  1875 
  1876 * Theory List:
  1877 
  1878 The following theorems have been eliminated or modified
  1879 (INCOMPATIBILITY):
  1880 
  1881   list_all_Nil       now named list_all.simps(1)
  1882   list_all_Cons      now named list_all.simps(2)
  1883   list_all_conv      now named list_all_iff
  1884   set_mem_eq         now named mem_iff
  1885 
  1886 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1887 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1888 
  1889 
  1890 *** HOL-Complex ***
  1891 
  1892 * Theory RealDef: better support for embedding natural numbers and
  1893 integers in the reals.
  1894 
  1895 The following theorems have been eliminated or modified
  1896 (INCOMPATIBILITY):
  1897 
  1898   exp_ge_add_one_self  now requires no hypotheses
  1899   real_of_int_add      reversed direction of equality (use [symmetric])
  1900   real_of_int_minus    reversed direction of equality (use [symmetric])
  1901   real_of_int_diff     reversed direction of equality (use [symmetric])
  1902   real_of_int_mult     reversed direction of equality (use [symmetric])
  1903 
  1904 * Theory RComplete: expanded support for floor and ceiling functions.
  1905 
  1906 * Theory Ln is new, with properties of the natural logarithm
  1907 
  1908 * Hyperreal: There is a new type constructor "star" for making
  1909 nonstandard types.  The old type names are now type synonyms:
  1910 
  1911   hypreal = real star
  1912   hypnat = nat star
  1913   hcomplex = complex star
  1914 
  1915 * Hyperreal: Many groups of similarly-defined constants have been
  1916 replaced by polymorphic versions (INCOMPATIBILITY):
  1917 
  1918   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1919 
  1920   starset      <-- starsetNat, starsetC
  1921   *s*          <-- *sNat*, *sc*
  1922   starset_n    <-- starsetNat_n, starsetC_n
  1923   *sn*         <-- *sNatn*, *scn*
  1924   InternalSets <-- InternalNatSets, InternalCSets
  1925 
  1926   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1927   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1928   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1929   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1930   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1931 
  1932 * Hyperreal: Many type-specific theorems have been removed in favor of
  1933 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1934 
  1935   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1936   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1937   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1938   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1939   right_minus <-- hypreal_add_minus
  1940   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1941   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1942   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1943   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1944   mult_1_right <-- hcomplex_mult_one_right
  1945   mult_zero_left <-- hcomplex_mult_zero_left
  1946   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1947   right_distrib <-- hypnat_add_mult_distrib2
  1948   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1949   right_inverse <-- hypreal_mult_inverse
  1950   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1951   order_refl <-- {hypreal,hypnat}_le_refl
  1952   order_trans <-- {hypreal,hypnat}_le_trans
  1953   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1954   order_less_le <-- {hypreal,hypnat}_less_le
  1955   linorder_linear <-- {hypreal,hypnat}_le_linear
  1956   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1957   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1958   add_nonneg_nonneg <-- hypreal_le_add_order
  1959 
  1960 * Hyperreal: Separate theorems having to do with type-specific
  1961 versions of constants have been merged into theorems that apply to the
  1962 new polymorphic constants (INCOMPATIBILITY):
  1963 
  1964   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1965   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1966   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1967   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1968   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1969   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1970   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1971   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1972   STAR_diff <-- {STAR,STARC}_diff
  1973   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1974     STARC_hcomplex_of_complex}_image_subset
  1975   starset_n_Un <-- starset{Nat,C}_n_Un
  1976   starset_n_Int <-- starset{Nat,C}_n_Int
  1977   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1978   starset_n_diff <-- starset{Nat,C}_n_diff
  1979   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1980   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1981   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1982   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1983   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1984   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1985   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1986   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1987   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1988   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1989   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1990   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1991   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1992   starfun_diff <-- starfun{C,RC,CR}_diff
  1993   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1994   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1995   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1996   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1997   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1998   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1999   starfun_Id <-- starfunC_Id
  2000   starfun_approx <-- starfun{Nat,CR}_approx
  2001   starfun_capprox <-- starfun{C,RC}_capprox
  2002   starfun_abs <-- starfunNat_rabs
  2003   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2004   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2005   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2006   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2007   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2008   starfun_add_approx <-- starfunCR_add_approx
  2009   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2010   starfun_divide <-- starfun{C,CR,RC}_divide
  2011   starfun_n <-- starfun{Nat,C}_n
  2012   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2013   starfun_n_add <-- starfun{Nat,C}_n_add
  2014   starfun_n_add_minus <-- starfunNat_n_add_minus
  2015   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2016   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2017   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2018 
  2019   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2020   star_n_minus <-- {hypreal,hcomplex}_minus
  2021   star_n_diff <-- {hypreal,hcomplex}_diff
  2022   star_n_mult <-- {hypreal,hcomplex}_mult
  2023   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2024   star_n_le <-- {hypreal,hypnat}_le
  2025   star_n_less <-- {hypreal,hypnat}_less
  2026   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2027   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2028   star_n_abs <-- hypreal_hrabs
  2029   star_n_divide <-- hcomplex_divide
  2030 
  2031   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2032   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2033   star_of_diff <-- hypreal_of_real_diff
  2034   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2035   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2036   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2037   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2038   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2039   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2040   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2041   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2042   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2043   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2044   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2045   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2046   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2047   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2048   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2049   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2050   star_of_power <-- hypreal_of_real_power
  2051   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2052 
  2053 * Hyperreal: new method "transfer" that implements the transfer
  2054 principle of nonstandard analysis. With a subgoal that mentions
  2055 nonstandard types like "'a star", the command "apply transfer"
  2056 replaces it with an equivalent one that mentions only standard types.
  2057 To be successful, all free variables must have standard types; non-
  2058 standard variables must have explicit universal quantifiers.
  2059 
  2060 * Hyperreal: A theory of Taylor series.
  2061 
  2062 
  2063 *** HOLCF ***
  2064 
  2065 * Discontinued special version of 'constdefs' (which used to support
  2066 continuous functions) in favor of the general Pure one with full
  2067 type-inference.
  2068 
  2069 * New simplification procedure for solving continuity conditions; it
  2070 is much faster on terms with many nested lambda abstractions (cubic
  2071 instead of exponential time).
  2072 
  2073 * New syntax for domain package: selector names are now optional.
  2074 Parentheses should be omitted unless argument is lazy, for example:
  2075 
  2076   domain 'a stream = cons "'a" (lazy "'a stream")
  2077 
  2078 * New command 'fixrec' for defining recursive functions with pattern
  2079 matching; defining multiple functions with mutual recursion is also
  2080 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2081 sinr, or any data constructor defined by the domain package. The given
  2082 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2083 syntax and examples.
  2084 
  2085 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2086 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2087 but the proof obligation additionally includes an admissibility
  2088 requirement. The packages generate instances of class cpo or pcpo,
  2089 with continuity and strictness theorems for Rep and Abs.
  2090 
  2091 * HOLCF: Many theorems have been renamed according to a more standard naming
  2092 scheme (INCOMPATIBILITY):
  2093 
  2094   foo_inject:  "foo$x = foo$y ==> x = y"
  2095   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2096   foo_less:    "(foo$x << foo$y) = (x << y)"
  2097   foo_strict:  "foo$UU = UU"
  2098   foo_defined: "... ==> foo$x ~= UU"
  2099   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2100 
  2101 
  2102 *** ZF ***
  2103 
  2104 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2105 including the First Isomorphism Theorem (on quotienting by the kernel
  2106 of a homomorphism).
  2107 
  2108 * ZF/Simplifier: install second copy of type solver that actually
  2109 makes use of TC rules declared to Isar proof contexts (or locales);
  2110 the old version is still required for ML proof scripts.
  2111 
  2112 
  2113 *** Cube ***
  2114 
  2115 * Converted to Isar theory format; use locales instead of axiomatic
  2116 theories.
  2117 
  2118 
  2119 *** ML ***
  2120 
  2121 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2122 for ||>, ||>>, |>>,
  2123 
  2124 * Pure/library.ML no longer defines its own option datatype, but uses
  2125 that of the SML basis, which has constructors NONE and SOME instead of
  2126 None and Some, as well as exception Option.Option instead of OPTION.
  2127 The functions the, if_none, is_some, is_none have been adapted
  2128 accordingly, while Option.map replaces apsome.
  2129 
  2130 * Pure/library.ML: the exception LIST has been given up in favour of
  2131 the standard exceptions Empty and Subscript, as well as
  2132 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2133 superceded by the standard hd and tl functions etc.
  2134 
  2135 A number of basic list functions are no longer exported to the ML
  2136 toplevel, as they are variants of predefined functions.  The following
  2137 suggests how one can translate existing code:
  2138 
  2139     rev_append xs ys = List.revAppend (xs, ys)
  2140     nth_elem (i, xs) = List.nth (xs, i)
  2141     last_elem xs = List.last xs
  2142     flat xss = List.concat xss
  2143     seq fs = List.app fs
  2144     partition P xs = List.partition P xs
  2145     mapfilter f xs = List.mapPartial f xs
  2146 
  2147 * Pure/library.ML: several combinators for linear functional
  2148 transformations, notably reverse application and composition:
  2149 
  2150   x |> f                f #> g
  2151   (x, y) |-> f          f #-> g
  2152 
  2153 * Pure/library.ML: introduced/changed precedence of infix operators:
  2154 
  2155   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2156   infix 2 ?;
  2157   infix 3 o oo ooo oooo;
  2158   infix 4 ~~ upto downto;
  2159 
  2160 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2161 infix operators.
  2162 
  2163 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2164 fold_map support linear functional transformations and nesting.  For
  2165 example:
  2166 
  2167   fold f [x1, ..., xN] y =
  2168     y |> f x1 |> ... |> f xN
  2169 
  2170   (fold o fold) f [xs1, ..., xsN] y =
  2171     y |> fold f xs1 |> ... |> fold f xsN
  2172 
  2173   fold f [x1, ..., xN] =
  2174     f x1 #> ... #> f xN
  2175 
  2176   (fold o fold) f [xs1, ..., xsN] =
  2177     fold f xs1 #> ... #> fold f xsN
  2178 
  2179 * Pure/library.ML: the following selectors on type 'a option are
  2180 available:
  2181 
  2182   the:               'a option -> 'a  (*partial*)
  2183   these:             'a option -> 'a  where 'a = 'b list
  2184   the_default: 'a -> 'a option -> 'a
  2185   the_list:          'a option -> 'a list
  2186 
  2187 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2188 basic operations for association lists, following natural argument
  2189 order; moreover the explicit equality predicate passed here avoids
  2190 potentially expensive polymorphic runtime equality checks.
  2191 The old functions may be expressed as follows:
  2192 
  2193   assoc = uncurry (AList.lookup (op =))
  2194   assocs = these oo AList.lookup (op =)
  2195   overwrite = uncurry (AList.update (op =)) o swap
  2196 
  2197 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2198 
  2199   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2200   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2201 
  2202 replacing make_keylist and keyfilter (occassionally used)
  2203 Naive rewrites:
  2204 
  2205   make_keylist = AList.make
  2206   keyfilter = AList.find (op =)
  2207 
  2208 * eq_fst and eq_snd now take explicit equality parameter, thus
  2209   avoiding eqtypes. Naive rewrites:
  2210 
  2211     eq_fst = eq_fst (op =)
  2212     eq_snd = eq_snd (op =)
  2213 
  2214 * Removed deprecated apl and apr (rarely used).
  2215   Naive rewrites:
  2216 
  2217     apl (n, op) =>>= curry op n
  2218     apr (op, m) =>>= fn n => op (n, m)
  2219 
  2220 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2221 provides a reasonably efficient light-weight implementation of sets as
  2222 lists.
  2223 
  2224 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2225 few new operations; existing lookup and update are now curried to
  2226 follow natural argument order (for use with fold etc.);
  2227 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2228 
  2229 * Pure/General: output via the Isabelle channels of
  2230 writeln/warning/error etc. is now passed through Output.output, with a
  2231 hook for arbitrary transformations depending on the print_mode
  2232 (cf. Output.add_mode -- the first active mode that provides a output
  2233 function wins).  Already formatted output may be embedded into further
  2234 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2235 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2236 accommodate easy composition of diagnostic messages etc.  Programmers
  2237 rarely need to care about Output.output or Output.raw at all, with
  2238 some notable exceptions: Output.output is required when bypassing the
  2239 standard channels (writeln etc.), or in token translations to produce
  2240 properly formatted results; Output.raw is required when capturing
  2241 already output material that will eventually be presented to the user
  2242 a second time.  For the default print mode, both Output.output and
  2243 Output.raw have no effect.
  2244 
  2245 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2246 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2247 cumulative results are displayed at the end of a batch session.
  2248 
  2249 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2250 replaced by File.platform_path and File.shell_path (with appropriate
  2251 hooks).  This provides a clean interface for unusual systems where the
  2252 internal and external process view of file names are different.
  2253 
  2254 * Pure: more efficient orders for basic syntactic entities: added
  2255 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2256 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2257 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2258 orders now -- potential INCOMPATIBILITY for code that depends on a
  2259 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2260 Library.sort_strings on result).
  2261 
  2262 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2263 fold_types traverse types/terms from left to right, observing natural
  2264 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2265 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2266 
  2267 * Pure: name spaces have been refined, with significant changes of the
  2268 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2269 to extern(_table).  The plain name entry path is superceded by a
  2270 general 'naming' context, which also includes the 'policy' to produce
  2271 a fully qualified name and external accesses of a fully qualified
  2272 name; NameSpace.extend is superceded by context dependent
  2273 Sign.declare_name.  Several theory and proof context operations modify
  2274 the naming context.  Especially note Theory.restore_naming and
  2275 ProofContext.restore_naming to get back to a sane state; note that
  2276 Theory.add_path is no longer sufficient to recover from
  2277 Theory.absolute_path in particular.
  2278 
  2279 * Pure: new flags short_names (default false) and unique_names
  2280 (default true) for controlling output of qualified names.  If
  2281 short_names is set, names are printed unqualified.  If unique_names is
  2282 reset, the name prefix is reduced to the minimum required to achieve
  2283 the original result when interning again, even if there is an overlap
  2284 with earlier declarations.
  2285 
  2286 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2287 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2288 (useful for printing error messages).  INCOMPATIBILITY.
  2289 
  2290 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2291 Theory.theory are now identified, referring to the universal
  2292 Context.theory (see Pure/context.ML).  Actual signature and theory
  2293 content is managed as theory data.  The old code and interfaces were
  2294 spread over many files and structures; the new arrangement introduces
  2295 considerable INCOMPATIBILITY to gain more clarity:
  2296 
  2297   Context -- theory management operations (name, identity, inclusion,
  2298     parents, ancestors, merge, etc.), plus generic theory data;
  2299 
  2300   Sign -- logical signature and syntax operations (declaring consts,
  2301     types, etc.), plus certify/read for common entities;
  2302 
  2303   Theory -- logical theory operations (stating axioms, definitions,
  2304     oracles), plus a copy of logical signature operations (consts,
  2305     types, etc.); also a few basic management operations (Theory.copy,
  2306     Theory.merge, etc.)
  2307 
  2308 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2309 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2310 for convenience -- they merely return the theory.
  2311 
  2312 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2313 
  2314 * Pure: the Isar proof context type is already defined early in Pure
  2315 as Context.proof (note that ProofContext.context and Proof.context are
  2316 aliases, where the latter is the preferred name).  This enables other
  2317 Isabelle components to refer to that type even before Isar is present.
  2318 
  2319 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2320 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2321 any of these kinds.  For example, Sign.intern typeK is now
  2322 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2323 Theory.hide_types.  Also note that former
  2324 Theory.hide_classes/types/consts are now
  2325 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2326 internalize their arguments!  INCOMPATIBILITY.
  2327 
  2328 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2329 datatype thmref (with constructors Name and NameSelection) instead of
  2330 plain string -- INCOMPATIBILITY;
  2331 
  2332 * Pure: cases produced by proof methods specify options, where NONE
  2333 means to remove case bindings -- INCOMPATIBILITY in
  2334 (RAW_)METHOD_CASES.
  2335 
  2336 * Pure: the following operations retrieve axioms or theorems from a
  2337 theory node or theory hierarchy, respectively:
  2338 
  2339   Theory.axioms_of: theory -> (string * term) list
  2340   Theory.all_axioms_of: theory -> (string * term) list
  2341   PureThy.thms_of: theory -> (string * thm) list
  2342   PureThy.all_thms_of: theory -> (string * thm) list
  2343 
  2344 * Pure: print_tac now outputs the goal through the trace channel.
  2345 
  2346 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2347 Reference Toplevel.debug (default false) controls detailed printing
  2348 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2349 controls execution profiling -- set to 1 for time and 2 for space
  2350 (both increase the runtime).
  2351 
  2352 * Isar session: The initial use of ROOT.ML is now always timed,
  2353 i.e. the log will show the actual process times, in contrast to the
  2354 elapsed wall-clock time that the outer shell wrapper produces.
  2355 
  2356 * Simplifier: improved handling of bound variables (nameless
  2357 representation, avoid allocating new strings).  Simprocs that invoke
  2358 the Simplifier recursively should use Simplifier.inherit_bounds to
  2359 avoid local name clashes.  Failure to do so produces warnings
  2360 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2361 for further details.
  2362 
  2363 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2364 bindings for all theorems stored within a given theory; this may help
  2365 in porting non-Isar theories to Isar ones, while keeping ML proof
  2366 scripts for the time being.
  2367 
  2368 * ML operator HTML.with_charset specifies the charset begin used for
  2369 generated HTML files.  For example:
  2370 
  2371   HTML.with_charset "utf-8" use_thy "Hebrew";
  2372   HTML.with_charset "utf-8" use_thy "Chinese";
  2373 
  2374 
  2375 *** System ***
  2376 
  2377 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2378 isabelle, isatool etc.).
  2379 
  2380 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2381 isatool doc, isatool mkdir, display_drafts etc.).
  2382 
  2383 * isatool usedir: option -f allows specification of the ML file to be
  2384 used by Isabelle; default is ROOT.ML.
  2385 
  2386 * New isatool version outputs the version identifier of the Isabelle
  2387 distribution being used.
  2388 
  2389 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2390 (containing Boolean satisfiability problems) into Isabelle/HOL
  2391 theories.
  2392 
  2393 
  2394 
  2395 New in Isabelle2004 (April 2004)
  2396 --------------------------------
  2397 
  2398 *** General ***
  2399 
  2400 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2401   Replaces linorder.ML.
  2402 
  2403 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2404   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2405   (\<a>...\<z>), are now considered normal letters, and can therefore
  2406   be used anywhere where an ASCII letter (a...zA...Z) has until
  2407   now. COMPATIBILITY: This obviously changes the parsing of some
  2408   terms, especially where a symbol has been used as a binder, say
  2409   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2410   as an identifier.  Fix it by inserting a space around former
  2411   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2412   existing theory and ML files.
  2413 
  2414 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2415 
  2416 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2417   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2418   a normal (but invisible) letter. For multiple letter subscripts repeat
  2419   \<^isub> like this: x\<^isub>1\<^isub>2.
  2420 
  2421 * Pure: There are now sub-/superscripts that can span more than one
  2422   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2423   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2424   superscript. The new control characters are not identifier parts.
  2425 
  2426 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2427   content of "..." to the latex file instead of \isacntrl... . The "..."
  2428   may consist of any printable characters excluding the end bracket >.
  2429 
  2430 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2431   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2432   declare constants "final", which prevents their being given a definition
  2433   later.  It is useful for constants whose behaviour is fixed axiomatically
  2434   rather than definitionally, such as the meta-logic connectives.
  2435 
  2436 * Pure: 'instance' now handles general arities with general sorts
  2437   (i.e. intersections of classes),
  2438 
  2439 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2440   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2441   It can be changed to alter the colors/layout of generated pages.
  2442 
  2443 
  2444 *** Isar ***
  2445 
  2446 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2447   cut_tac, subgoal_tac and thin_tac:
  2448   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2449     locales are no longer forced to write Isar proof scripts.
  2450     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2451     emulations.
  2452   - INCOMPATIBILITY: names of variables to be instantiated may no
  2453     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2454     This is consistent with the instantiation attribute "where".
  2455 
  2456 * Attributes "where" and "of":
  2457   - Now take type variables of instantiated theorem into account when reading
  2458     the instantiation string.  This fixes a bug that caused instantiated
  2459     theorems to have too special types in some circumstances.
  2460   - "where" permits explicit instantiations of type variables.
  2461 
  2462 * Calculation commands "moreover" and "also" no longer interfere with
  2463   current facts ("this"), admitting arbitrary combinations with "then"
  2464   and derived forms.
  2465 
  2466 * Locales:
  2467   - Goal statements involving the context element "includes" no longer
  2468     generate theorems with internal delta predicates (those ending on
  2469     "_axioms") in the premise.
  2470     Resolve particular premise with <locale>.intro to obtain old form.
  2471   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2472     specification and "includes" elements in goal statement.
  2473   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2474     [intro?] and [elim?] (respectively) by default.
  2475   - Experimental command for instantiation of locales in proof contexts:
  2476         instantiate <label>[<attrs>]: <loc>
  2477     Instantiates locale <loc> and adds all its theorems to the current context
  2478     taking into account their attributes.  Label and attrs are optional
  2479     modifiers, like in theorem declarations.  If present, names of
  2480     instantiated theorems are qualified with <label>, and the attributes
  2481     <attrs> are applied after any attributes these theorems might have already.
  2482       If the locale has assumptions, a chained fact of the form
  2483     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2484     are derived.  The command does not support old-style locales declared
  2485     with "locale (open)".
  2486       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2487 
  2488 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2489   (Isar) contexts.
  2490 
  2491 
  2492 *** HOL ***
  2493 
  2494 * Proof import: new image HOL4 contains the imported library from
  2495   the HOL4 system with about 2500 theorems. It is imported by
  2496   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2497   can be used like any other Isabelle image.  See
  2498   HOL/Import/HOL/README for more information.
  2499 
  2500 * Simplifier:
  2501   - Much improved handling of linear and partial orders.
  2502     Reasoners for linear and partial orders are set up for type classes
  2503     "linorder" and "order" respectively, and are added to the default simpset
  2504     as solvers.  This means that the simplifier can build transitivity chains
  2505     to solve goals from the assumptions.
  2506   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2507     of blast or auto after simplification become unnecessary because the goal
  2508     is solved by simplification already.
  2509 
  2510 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2511     all proved in axiomatic type classes for semirings, rings and fields.
  2512 
  2513 * Numerics:
  2514   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2515     now formalized using the Ring_and_Field theory mentioned above.
  2516   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2517     than before, because now they are set up once in a generic manner.
  2518   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2519     Look for the general versions in Ring_and_Field (and Power if they concern
  2520     exponentiation).
  2521 
  2522 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2523 
  2524 * Records:
  2525   - Record types are now by default printed with their type abbreviation
  2526     instead of the list of all field types. This can be configured via
  2527     the reference "print_record_type_abbr".
  2528   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2529     (not enabled by default).
  2530   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2531     EX x. x = sel r to True (not enabled by default).
  2532   - Tactic "record_split_simp_tac" to split and simplify records added.
  2533 
  2534 * 'specification' command added, allowing for definition by
  2535   specification.  There is also an 'ax_specification' command that
  2536   introduces the new constants axiomatically.
  2537 
  2538 * arith(_tac) is now able to generate counterexamples for reals as well.
  2539 
  2540 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2541 
  2542 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2543   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2544 
  2545 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2546   matrix theory to linear programming.
  2547 
  2548 * Unions and Intersections:
  2549   The latex output syntax of UN and INT has been changed
  2550   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2551   i.e. the index formulae has become a subscript.
  2552   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2553 
  2554 * Unions and Intersections over Intervals:
  2555   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2556   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2557   like in normal math, and corresponding versions for < and for intersection.
  2558 
  2559 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2560   lexicographic dictonary ordering has been added as "lexord".
  2561 
  2562 * ML: the legacy theory structures Int and List have been removed. They had
  2563   conflicted with ML Basis Library structures having the same names.
  2564 
  2565 * 'refute' command added to search for (finite) countermodels.  Only works
  2566   for a fragment of HOL.  The installation of an external SAT solver is
  2567   highly recommended.  See "HOL/Refute.thy" for details.
  2568 
  2569 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2570   formulae under an assignment of free variables to random values.
  2571   In contrast to 'refute', it can deal with inductive datatypes,
  2572   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2573   for examples.
  2574 
  2575 
  2576 *** HOLCF ***
  2577 
  2578 * Streams now come with concatenation and are part of the HOLCF image
  2579 
  2580 
  2581 
  2582 New in Isabelle2003 (May 2003)
  2583 ------------------------------
  2584 
  2585 *** General ***
  2586 
  2587 * Provers/simplifier:
  2588 
  2589   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2590     Assumptions are now subject to complete mutual simplification,
  2591     not just from left to right. The simplifier now preserves
  2592     the order of assumptions.
  2593 
  2594     Potential INCOMPATIBILITY:
  2595 
  2596     -- simp sometimes diverges where the old version did
  2597        not, e.g. invoking simp on the goal
  2598 
  2599         [| P (f x); y = x; f x = f y |] ==> Q
  2600 
  2601        now gives rise to the infinite reduction sequence
  2602 
  2603         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2604 
  2605        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2606        kind of problem.
  2607 
  2608     -- Tactics combining classical reasoner and simplification (such as auto)
  2609        are also affected by this change, because many of them rely on
  2610        simp. They may sometimes diverge as well or yield a different numbers
  2611        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2612        in case of problems. Sometimes subsequent calls to the classical
  2613        reasoner will fail because a preceeding call to the simplifier too
  2614        eagerly simplified the goal, e.g. deleted redundant premises.
  2615 
  2616   - The simplifier trace now shows the names of the applied rewrite rules
  2617 
  2618   - You can limit the number of recursive invocations of the simplifier
  2619     during conditional rewriting (where the simplifie tries to solve the
  2620     conditions before applying the rewrite rule):
  2621     ML "simp_depth_limit := n"
  2622     where n is an integer. Thus you can force termination where previously
  2623     the simplifier would diverge.
  2624 
  2625   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2626 
  2627   - No longer aborts on failed congruence proof.  Instead, the
  2628     congruence is ignored.
  2629 
  2630 * Pure: New generic framework for extracting programs from constructive
  2631   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2632   as HOL/Extraction for some case studies.
  2633 
  2634 * Pure: The main goal of the proof state is no longer shown by default, only
  2635 the subgoals. This behaviour is controlled by a new flag.
  2636    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2637 (ML: Proof.show_main_goal).
  2638 
  2639 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2640 rules whose conclusion matches subgoal 1:
  2641       PG menu: Isabelle/Isar -> Show me -> matching rules
  2642 The rules are ordered by how closely they match the subgoal.
  2643 In particular, rules that solve a subgoal outright are displayed first
  2644 (or rather last, the way they are printed).
  2645 (ML: ProofGeneral.print_intros())
  2646 
  2647 * Pure: New flag trace_unify_fail causes unification to print
  2648 diagnostic information (PG: in trace buffer) when it fails. This is
  2649 useful for figuring out why single step proofs like rule, erule or
  2650 assumption failed.
  2651 
  2652 * Pure: Locale specifications now produce predicate definitions
  2653 according to the body of text (covering assumptions modulo local
  2654 definitions); predicate "loc_axioms" covers newly introduced text,
  2655 while "loc" is cumulative wrt. all included locale expressions; the
  2656 latter view is presented only on export into the global theory
  2657 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2658 on the old view without predicates;
  2659 
  2660 * Pure: predefined locales "var" and "struct" are useful for sharing
  2661 parameters (as in CASL, for example); just specify something like
  2662 ``var x + var y + struct M'' as import;
  2663 
  2664 * Pure: improved thms_containing: proper indexing of facts instead of
  2665 raw theorems; check validity of results wrt. current name space;
  2666 include local facts of proof configuration (also covers active
  2667 locales), cover fixed variables in index; may use "_" in term
  2668 specification; an optional limit for the number of printed facts may
  2669 be given (the default is 40);
  2670 
  2671 * Pure: disallow duplicate fact bindings within new-style theory files
  2672 (batch-mode only);
  2673 
  2674 * Provers: improved induct method: assumptions introduced by case
  2675 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2676 the goal statement); "foo" still refers to all facts collectively;
  2677 
  2678 * Provers: the function blast.overloaded has been removed: all constants
  2679 are regarded as potentially overloaded, which improves robustness in exchange
  2680 for slight decrease in efficiency;
  2681 
  2682 * Provers/linorder: New generic prover for transitivity reasoning over
  2683 linear orders.  Note: this prover is not efficient!
  2684 
  2685 * Isar: preview of problems to finish 'show' now produce an error
  2686 rather than just a warning (in interactive mode);
  2687 
  2688 
  2689 *** HOL ***
  2690 
  2691 * arith(_tac)
  2692 
  2693  - Produces a counter example if it cannot prove a goal.
  2694    Note that the counter example may be spurious if the goal is not a formula
  2695    of quantifier-free linear arithmetic.
  2696    In ProofGeneral the counter example appears in the trace buffer.
  2697 
  2698  - Knows about div k and mod k where k is a numeral of type nat or int.
  2699 
  2700  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2701    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2702    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2703 
  2704 * simp's arithmetic capabilities have been enhanced a bit: it now
  2705 takes ~= in premises into account (by performing a case split);
  2706 
  2707 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2708 are distributed over a sum of terms;
  2709 
  2710 * New tactic "trans_tac" and method "trans" instantiate
  2711 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2712 "<=", "<" and "=").
  2713 
  2714 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2715 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2716 
  2717 * 'typedef' command has new option "open" to suppress the set
  2718 definition;
  2719 
  2720 * functions Min and Max on finite sets have been introduced (theory
  2721 Finite_Set);
  2722 
  2723 * attribute [symmetric] now works for relations as well; it turns
  2724 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2725 
  2726 * induct over a !!-quantified statement (say !!x1..xn):
  2727   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2728 
  2729 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2730 %x. None. Warning: empty_def now refers to the previously hidden definition
  2731 of the empty set.
  2732 
  2733 * Algebra: formalization of classical algebra.  Intended as base for
  2734 any algebraic development in Isabelle.  Currently covers group theory
  2735 (up to Sylow's theorem) and ring theory (Universal Property of
  2736 Univariate Polynomials).  Contributions welcome;
  2737 
  2738 * GroupTheory: deleted, since its material has been moved to Algebra;
  2739 
  2740 * Complex: new directory of the complex numbers with numeric constants,
  2741 nonstandard complex numbers, and some complex analysis, standard and
  2742 nonstandard (Jacques Fleuriot);
  2743 
  2744 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2745 
  2746 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2747 Fleuriot);
  2748 
  2749 * Real/HahnBanach: updated and adapted to locales;
  2750 
  2751 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2752 Gray and Kramer);
  2753 
  2754 * UNITY: added the Meier-Sanders theory of progress sets;
  2755 
  2756 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2757 as abstract algorithms, instantiated to the JVM;
  2758 
  2759 * Bali: Java source language formalization. Type system, operational
  2760 semantics, axiomatic semantics. Supported language features:
  2761 classes, interfaces, objects,virtual methods, static methods,
  2762 static/instance fields, arrays, access modifiers, definite
  2763 assignment, exceptions.
  2764 
  2765 
  2766 *** ZF ***
  2767 
  2768 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2769 universe, etc.);
  2770 
  2771 * Main ZF: virtually all theories converted to new-style format;
  2772 
  2773 
  2774 *** ML ***
  2775 
  2776 * Pure: Tactic.prove provides sane interface for internal proofs;
  2777 omits the infamous "standard" operation, so this is more appropriate
  2778 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2779 
  2780 * Pure: improved error reporting of simprocs;
  2781 
  2782 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2783 up simprocs;
  2784 
  2785 
  2786 *** Document preparation ***
  2787 
  2788 * uses \par instead of \\ for line breaks in theory text. This may
  2789 shift some page breaks in large documents. To get the old behaviour
  2790 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2791 
  2792 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2793 other packages
  2794 
  2795 * \<euro> now needs package babel/greek instead of marvosym (which
  2796 broke \Rightarrow)
  2797 
  2798 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2799 textcomp package)
  2800 
  2801 
  2802 
  2803 New in Isabelle2002 (March 2002)
  2804 --------------------------------
  2805 
  2806 *** Document preparation ***
  2807 
  2808 * greatly simplified document preparation setup, including more
  2809 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2810 instructive isatool mkdir; users should basically be able to get
  2811 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2812 users may run a separate document processing stage manually like this:
  2813 "isatool usedir -D output HOL Test && isatool document Test/output";
  2814 
  2815 * theory dependency graph may now be incorporated into documents;
  2816 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2817 with \includegraphics of LaTeX;
  2818 
  2819 * proper spacing of consecutive markup elements, especially text
  2820 blocks after section headings;
  2821 
  2822 * support bold style (for single symbols only), input syntax is like
  2823 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2824 
  2825 * \<bullet> is now output as bold \cdot by default, which looks much
  2826 better in printed text;
  2827 
  2828 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2829 note that these symbols are currently unavailable in Proof General /
  2830 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2831 
  2832 * isatool latex no longer depends on changed TEXINPUTS, instead
  2833 isatool document copies the Isabelle style files to the target
  2834 location;
  2835 
  2836 
  2837 *** Isar ***
  2838 
  2839 * Pure/Provers: improved proof by cases and induction;
  2840   - 'case' command admits impromptu naming of parameters (such as
  2841     "case (Suc n)");
  2842   - 'induct' method divinates rule instantiation from the inductive
  2843     claim; no longer requires excessive ?P bindings for proper
  2844     instantiation of cases;
  2845   - 'induct' method properly enumerates all possibilities of set/type
  2846     rules; as a consequence facts may be also passed through *type*
  2847     rules without further ado;
  2848   - 'induct' method now derives symbolic cases from the *rulified*
  2849     rule (before it used to rulify cases stemming from the internal
  2850     atomized version); this means that the context of a non-atomic
  2851     statement becomes is included in the hypothesis, avoiding the
  2852     slightly cumbersome show "PROP ?case" form;
  2853   - 'induct' may now use elim-style induction rules without chaining
  2854     facts, using ``missing'' premises from the goal state; this allows
  2855     rules stemming from inductive sets to be applied in unstructured
  2856     scripts, while still benefitting from proper handling of non-atomic
  2857     statements; NB: major inductive premises need to be put first, all
  2858     the rest of the goal is passed through the induction;
  2859   - 'induct' proper support for mutual induction involving non-atomic
  2860     rule statements (uses the new concept of simultaneous goals, see
  2861     below);
  2862   - append all possible rule selections, but only use the first
  2863     success (no backtracking);
  2864   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2865   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2866   - added 'print_induct_rules' (covered by help item in recent Proof
  2867     General versions);
  2868   - moved induct/cases attributes to Pure, methods to Provers;
  2869   - generic method setup instantiated for FOL and HOL;
  2870 
  2871 * Pure: support multiple simultaneous goal statements, for example
  2872 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2873 meta-level mechanism, this acts as if several individual goals had
  2874 been stated separately; in particular common proof methods need to be
  2875 repeated in order to cover all claims; note that a single elimination
  2876 step is *not* sufficient to establish the two conjunctions, so this
  2877 fails:
  2878 
  2879   assume "A & B" then have A and B ..   (*".." fails*)
  2880 
  2881 better use "obtain" in situations as above; alternative refer to
  2882 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2883 
  2884 * Pure: proper integration with ``locales''; unlike the original
  2885 version by Florian Kammller, Isar locales package high-level proof
  2886 contexts rather than raw logical ones (e.g. we admit to include
  2887 attributes everywhere); operations on locales include merge and
  2888 rename; support for implicit arguments (``structures''); simultaneous
  2889 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2890 some examples;
  2891 
  2892 * Pure: the following commands have been ``localized'', supporting a
  2893 target locale specification "(in name)": 'lemma', 'theorem',
  2894 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2895 stored both within the locale and at the theory level (exported and
  2896 qualified by the locale name);
  2897 
  2898 * Pure: theory goals may now be specified in ``long'' form, with
  2899 ad-hoc contexts consisting of arbitrary locale elements. for example
  2900 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2901 definitions may be given, too); the result is a meta-level rule with
  2902 the context elements being discharged in the obvious way;
  2903 
  2904 * Pure: new proof command 'using' allows to augment currently used
  2905 facts after a goal statement ('using' is syntactically analogous to
  2906 'apply', but acts on the goal's facts only); this allows chained facts
  2907 to be separated into parts given before and after a claim, as in
  2908 ``from a and b have C using d and e <proof>'';
  2909 
  2910 * Pure: renamed "antecedent" case to "rule_context";
  2911 
  2912 * Pure: new 'judgment' command records explicit information about the
  2913 object-logic embedding (used by several tools internally); no longer
  2914 use hard-wired "Trueprop";
  2915 
  2916 * Pure: added 'corollary' command;
  2917 
  2918 * Pure: fixed 'token_translation' command;
  2919 
  2920 * Pure: removed obsolete 'exported' attribute;
  2921 
  2922 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2923 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2924 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2925 
  2926 * Pure: method 'atomize' presents local goal premises as object-level
  2927 statements (atomic meta-level propositions); setup controlled via
  2928 rewrite rules declarations of 'atomize' attribute; example
  2929 application: 'induct' method with proper rule statements in improper
  2930 proof *scripts*;
  2931 
  2932 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2933 now consider the syntactic context of assumptions, giving a better
  2934 chance to get type-inference of the arguments right (this is
  2935 especially important for locales);
  2936 
  2937 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2938 mode;
  2939 
  2940 * Pure/obtain: the formal conclusion "thesis", being marked as
  2941 ``internal'', may no longer be reference directly in the text;
  2942 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2943 situations;
  2944 
  2945 * Pure: generic 'sym' attribute which declares a rule both as pure
  2946 'elim?' and for the 'symmetric' operation;
  2947 
  2948 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2949 text; the fixed correlation with particular command syntax has been
  2950 discontinued;
  2951 
  2952 * Pure: new method 'rules' is particularly well-suited for proof
  2953 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2954 but often produces more compact proof terms with less detours;
  2955 
  2956 * Pure/Provers/classical: simplified integration with pure rule
  2957 attributes and methods; the classical "intro?/elim?/dest?"
  2958 declarations coincide with the pure ones; the "rule" method no longer
  2959 includes classically swapped intros; "intro" and "elim" methods no
  2960 longer pick rules from the context; also got rid of ML declarations
  2961 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2962 INCOMPATIBILITY;
  2963 
  2964 * Provers/classical: attribute 'swapped' produces classical inversions
  2965 of introduction rules;
  2966 
  2967 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2968 rules instead of full simplifier context; 'iff' attribute handles
  2969 conditional rules;
  2970 
  2971 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2972 
  2973 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2974 "(permissive)" option to recover old behavior;
  2975 
  2976 * HOL: 'inductive' no longer features separate (collective) attributes
  2977 for 'intros' (was found too confusing);
  2978 
  2979 * HOL: properly declared induction rules less_induct and
  2980 wf_induct_rule;
  2981 
  2982 
  2983 *** HOL ***
  2984 
  2985 * HOL: moved over to sane numeral syntax; the new policy is as
  2986 follows:
  2987 
  2988   - 0 and 1 are polymorphic constants, which are defined on any
  2989   numeric type (nat, int, real etc.);
  2990 
  2991   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2992   binary representation internally;
  2993 
  2994   - type nat has special constructor Suc, and generally prefers Suc 0
  2995   over 1::nat and Suc (Suc 0) over 2::nat;
  2996 
  2997 This change may cause significant problems of INCOMPATIBILITY; here
  2998 are some hints on converting existing sources:
  2999 
  3000   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3001   entities, so expressions involving "-" (unary or binary minus) need
  3002   to be spaced properly;
  3003 
  3004   - existing occurrences of "1" may need to be constraint "1::nat" or
  3005   even replaced by Suc 0; similar for old "2";
  3006 
  3007   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3008 
  3009   - remove all special provisions on numerals in proofs;
  3010 
  3011 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3012 representation (depends on bin_arith_simps in the default context);
  3013 
  3014 * HOL: symbolic syntax for x^2 (numeral 2);
  3015 
  3016 * HOL: the class of all HOL types is now called "type" rather than
  3017 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3018 in axclass/classes, instance/arities, and (usually rare) occurrences
  3019 in typings (of consts etc.); internally the class is called
  3020 "HOL.type", ML programs should refer to HOLogic.typeS;
  3021 
  3022 * HOL/record package improvements:
  3023   - new derived operations "fields" to build a partial record section,
  3024     "extend" to promote a fixed record to a record scheme, and
  3025     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3026     declared as simp by default;
  3027   - shared operations ("more", "fields", etc.) now need to be always
  3028     qualified) --- potential INCOMPATIBILITY;
  3029   - removed "make_scheme" operations (use "make" with "extend") --
  3030     INCOMPATIBILITY;
  3031   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3032   - provides cases/induct rules for use with corresponding Isar
  3033     methods (for concrete records, record schemes, concrete more
  3034     parts, and schematic more parts -- in that order);
  3035   - internal definitions directly based on a light-weight abstract
  3036     theory of product types over typedef rather than datatype;
  3037 
  3038 * HOL: generic code generator for generating executable ML code from
  3039 specifications; specific support for HOL constructs such as inductive
  3040 datatypes and sets, as well as recursive functions; can be invoked
  3041 via 'generate_code' theory section;
  3042 
  3043 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3044 
  3045 * HOL: consolidated and renamed several theories.  In particular:
  3046         Ord.thy has been absorbed into HOL.thy
  3047         String.thy has been absorbed into List.thy
  3048 
  3049 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3050 (beware of argument permutation!);
  3051 
  3052 * HOL: linorder_less_split superseded by linorder_cases;
  3053 
  3054 * HOL/List: "nodups" renamed to "distinct";
  3055 
  3056 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3057 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3058   - Ex_def has changed, now need to use some_eq_ex
  3059 
  3060 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3061 in this (rare) case use:
  3062 
  3063   delSWrapper "split_all_tac"
  3064   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3065 
  3066 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3067 MAY FAIL;
  3068 
  3069 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3070 Isabelle's type classes, ^ on functions and relations has too general
  3071 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3072 necessary to attach explicit type constraints;
  3073 
  3074 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3075 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3076 renamed accordingly (eg "compI" -> "rel_compI").
  3077 
  3078 * HOL: syntax translations now work properly with numerals and records
  3079 expressions;
  3080 
  3081 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3082 of "lam" -- INCOMPATIBILITY;
  3083 
  3084 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3085 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3086 renamed "Product_Type.unit";
  3087 
  3088 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3089 
  3090 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3091 the "cases" method);
  3092 
  3093 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3094 Florian Kammller);
  3095 
  3096 * HOL/IMP: updated and converted to new-style theory format; several
  3097 parts turned into readable document, with proper Isar proof texts and
  3098 some explanations (by Gerwin Klein);
  3099 
  3100 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3101 
  3102 * HOL-Hyperreal is now a logic image;
  3103 
  3104 
  3105 *** HOLCF ***
  3106 
  3107 * Isar: consts/constdefs supports mixfix syntax for continuous
  3108 operations;
  3109 
  3110 * Isar: domain package adapted to new-style theory format, e.g. see
  3111 HOLCF/ex/Dnat.thy;
  3112 
  3113 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3114 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3115 lift.induct_tac, always use UU instead of Undef;
  3116 
  3117 * HOLCF/IMP: updated and converted to new-style theory;
  3118 
  3119 
  3120 *** ZF ***
  3121 
  3122 * Isar: proper integration of logic-specific tools and packages,
  3123 including theory commands '(co)inductive', '(co)datatype',
  3124 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3125 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3126 
  3127 * theory Main no longer includes AC; for the Axiom of Choice, base
  3128 your theory on Main_ZFC;
  3129 
  3130 * the integer library now covers quotients and remainders, with many
  3131 laws relating division to addition, multiplication, etc.;
  3132 
  3133 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3134 typeless version of the formalism;
  3135 
  3136 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3137 format;
  3138 
  3139 * ZF/Induct: new directory for examples of inductive definitions,
  3140 including theory Multiset for multiset orderings; converted to
  3141 new-style theory format;
  3142 
  3143 * ZF: many new theorems about lists, ordinals, etc.;
  3144 
  3145 
  3146 *** General ***
  3147 
  3148 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3149 variable proof controls level of detail: 0 = no proofs (only oracle
  3150 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3151 also ref manual for further ML interfaces;
  3152 
  3153 * Pure/axclass: removed obsolete ML interface
  3154 goal_subclass/goal_arity;
  3155 
  3156 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3157 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3158 separate tokens, so expressions involving minus need to be spaced
  3159 properly;
  3160 
  3161 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3162 rather than "infixl" or "infixr";
  3163 
  3164 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3165 sort constraint specifications in type inference; e.g. "x::_::foo"
  3166 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3167 type variable);
  3168 
  3169 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3170 control output of nested => (types); the default behavior is
  3171 "type_brackets";
  3172 
  3173 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3174 tokens into AST constants;
  3175 
  3176 * Pure/syntax: prefer later declarations of translations and print
  3177 translation functions; potential INCOMPATIBILITY: need to reverse
  3178 multiple declarations for same syntax element constant;
  3179 
  3180 * Pure/show_hyps reset by default (in accordance to existing Isar
  3181 practice);
  3182 
  3183 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3184 addSafter;
  3185 
  3186 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3187 as well;
  3188 
  3189 * system: tested support for MacOS X; should be able to get Isabelle +
  3190 Proof General to work in a plain Terminal after installing Poly/ML
  3191 (e.g. from the Isabelle distribution area) and GNU bash alone
  3192 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3193 support requires further installations, e.g. from
  3194 http://fink.sourceforge.net/);
  3195 
  3196 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3197 
  3198 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3199 of 40 MB), cf. ML_OPTIONS;
  3200 
  3201 * system: Proof General keywords specification is now part of the
  3202 Isabelle distribution (see etc/isar-keywords.el);
  3203 
  3204 * system: support for persistent Proof General sessions (refrain from
  3205 outdating all loaded theories on startup); user may create writable
  3206 logic images like this: ``isabelle -q HOL Test'';
  3207 
  3208 * system: smart selection of Isabelle process versus Isabelle
  3209 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3210 run both "isabelle" and "Isabelle" even if file names are badly
  3211 damaged (executable inspects the case of the first letter of its own
  3212 name); added separate "isabelle-process" and "isabelle-interface";
  3213 
  3214 * system: refrain from any attempt at filtering input streams; no
  3215 longer support ``8bit'' encoding of old isabelle font, instead proper
  3216 iso-latin characters may now be used; the related isatools
  3217 "symbolinput" and "nonascii" have disappeared as well;
  3218 
  3219 * system: removed old "xterm" interface (the print modes "xterm" and
  3220 "xterm_color" are still available for direct use in a suitable
  3221 terminal);
  3222 
  3223 
  3224 
  3225 New in Isabelle99-2 (February 2001)
  3226 -----------------------------------
  3227 
  3228 *** Overview of INCOMPATIBILITIES ***
  3229 
  3230 * HOL: please note that theories in the Library and elsewhere often use the
  3231 new-style (Isar) format; to refer to their theorems in an ML script you must
  3232 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3233 
  3234 * HOL: inductive package no longer splits induction rule aggressively,
  3235 but only as far as specified by the introductions given; the old
  3236 format may be recovered via ML function complete_split_rule or attribute
  3237 'split_rule (complete)';
  3238 
  3239 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3240 gfp_Tarski to gfp_unfold;
  3241 
  3242 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3243 
  3244 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3245 relation); infix "^^" has been renamed "``"; infix "``" has been
  3246 renamed "`"; "univalent" has been renamed "single_valued";
  3247 
  3248 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3249 operation;
  3250 
  3251 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3252 
  3253 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3254 
  3255 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3256 consequence, it is no longer monotonic wrt. the local goal context
  3257 (which is now passed through the inductive cases);
  3258 
  3259 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3260 \<gg> to \<ggreater>;
  3261 
  3262 
  3263 *** Document preparation ***
  3264 
  3265 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3266 available: are "it" for near math-mode best-style output, "sl" for
  3267 slanted text style, and "tt" for plain type-writer; if no
  3268 \isabellestyle command is given, output is according to slanted
  3269 type-writer);
  3270 
  3271 * support sub/super scripts (for single symbols only), input syntax is
  3272 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3273 
  3274 * some more standard symbols; see Appendix A of the system manual for
  3275 the complete list of symbols defined in isabellesym.sty;
  3276 
  3277 * improved isabelle style files; more abstract symbol implementation
  3278 (should now use \isamath{...} and \isatext{...} in custom symbol
  3279 definitions);
  3280 
  3281 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3282 state; Note that presentation of goal states does not conform to
  3283 actual human-readable proof documents.  Please do not include goal
  3284 states into document output unless you really know what you are doing!
  3285 
  3286 * proper indentation of antiquoted output with proportional LaTeX
  3287 fonts;
  3288 
  3289 * no_document ML operator temporarily disables LaTeX document
  3290 generation;
  3291 
  3292 * isatool unsymbolize tunes sources for plain ASCII communication;
  3293 
  3294 
  3295 *** Isar ***
  3296 
  3297 * Pure: Isar now suffers initial goal statements to contain unbound
  3298 schematic variables (this does not conform to actual readable proof
  3299 documents, due to unpredictable outcome and non-compositional proof
  3300 checking); users who know what they are doing may use schematic goals
  3301 for Prolog-style synthesis of proven results;
  3302 
  3303 * Pure: assumption method (an implicit finishing) now handles actual
  3304 rules as well;
  3305 
  3306 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3307 initial goal, declare "that" only as Pure intro (only for single
  3308 steps); the "that" rule assumption may now be involved in implicit
  3309 finishing, thus ".." becomes a feasible for trivial obtains;
  3310 
  3311 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3312 instance proofs may be performed by "..";
  3313 
  3314 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3315 statements as well;
  3316 
  3317 * Pure: more robust selection of calculational rules;
  3318 
  3319 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3320 rule (as well as the assumption rule);
  3321 
  3322 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3323 lemmas, using the graph browser tool;
  3324 
  3325 * Pure: predict failure of "show" in interactive mode;
  3326 
  3327 * Pure: 'thms_containing' now takes actual terms as arguments;
  3328 
  3329 * HOL: improved method 'induct' --- now handles non-atomic goals
  3330 (potential INCOMPATIBILITY); tuned error handling;
  3331 
  3332 * HOL: cases and induct rules now provide explicit hints about the
  3333 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3334 any remaining facts are inserted into the goal verbatim;
  3335 
  3336 * HOL: local contexts (aka cases) may now contain term bindings as
  3337 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3338 the result to be shown in each case;
  3339 
  3340 * HOL: added 'recdef_tc' command;
  3341 
  3342 * isatool convert assists in eliminating legacy ML scripts;
  3343 
  3344 
  3345 *** HOL ***
  3346 
  3347 * HOL/Library: a collection of generic theories to be used together
  3348 with main HOL; the theory loader path already includes this directory
  3349 by default; the following existing theories have been moved here:
  3350 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3351 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3352 
  3353 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3354 modelling and verification task performed in Isabelle/HOL +
  3355 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3356 
  3357 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3358 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3359 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3360 'domain', this makes the theory consistent with mathematical
  3361 literature;
  3362 
  3363 * HOL basics: added overloaded operations "inverse" and "divide"
  3364 (infix "/"), syntax for generic "abs" operation, generic summation
  3365 operator \<Sum>;
  3366 
  3367 * HOL/typedef: simplified package, provide more useful rules (see also
  3368 HOL/subset.thy);
  3369 
  3370 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3371 now expressed as a proper nested rule (old-style tactic scripts may
  3372 require atomize_strip_tac to cope with non-atomic premises);
  3373 
  3374 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3375 to "split_conv" (old name still available for compatibility);
  3376 
  3377 * HOL: improved concrete syntax for strings (e.g. allows translation
  3378 rules with string literals);
  3379 
  3380 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3381  and Fleuriot's mechanization of analysis, including the transcendental
  3382  functions for the reals;
  3383 
  3384 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3385 
  3386 
  3387 *** CTT ***
  3388 
  3389 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3390 "lam" is displayed as TWO lambda-symbols
  3391 
  3392 * CTT: theory Main now available, containing everything (that is, Bool
  3393 and Arith);
  3394 
  3395 
  3396 *** General ***
  3397 
  3398 * Pure: the Simplifier has been implemented properly as a derived rule
  3399 outside of the actual kernel (at last!); the overall performance
  3400 penalty in practical applications is about 50%, while reliability of
  3401 the Isabelle inference kernel has been greatly improved;
  3402 
  3403 * print modes "brackets" and "no_brackets" control output of nested =>
  3404 (types) and ==> (props); the default behaviour is "brackets";
  3405 
  3406 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3407 as assumptions as well;
  3408 
  3409 * system: support Poly/ML 4.0;
  3410 
  3411 * system: isatool install handles KDE version 1 or 2;
  3412 
  3413 
  3414 
  3415 New in Isabelle99-1 (October 2000)
  3416 ----------------------------------
  3417 
  3418 *** Overview of INCOMPATIBILITIES ***
  3419 
  3420 * HOL: simplification of natural numbers is much changed; to partly
  3421 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3422 issue the following ML commands:
  3423 
  3424   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3425   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3426 
  3427 * HOL: simplification no longer dives into case-expressions; this is
  3428 controlled by "t.weak_case_cong" for each datatype t;
  3429 
  3430 * HOL: nat_less_induct renamed to less_induct;
  3431 
  3432 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3433 fixsome to patch .thy and .ML sources automatically;
  3434 
  3435   select_equality  -> some_equality
  3436   select_eq_Ex     -> some_eq_ex
  3437   selectI2EX       -> someI2_ex
  3438   selectI2         -> someI2
  3439   selectI          -> someI
  3440   select1_equality -> some1_equality
  3441   Eps_sym_eq       -> some_sym_eq_trivial
  3442   Eps_eq           -> some_eq_trivial
  3443 
  3444 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3445 
  3446 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3447 instead);
  3448 
  3449 * HOL: the recursion equations generated by 'recdef' are now called
  3450 f.simps instead of f.rules;
  3451 
  3452 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3453 
  3454 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3455 sometimes be needed;
  3456 
  3457 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3458 
  3459 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3460 
  3461 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3462 product is now "<*>" instead of "Times"; the lexicographic product is
  3463 now "<*lex*>" instead of "**";
  3464 
  3465 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3466 of main HOL, but was unused); better use HOL's datatype package;
  3467 
  3468 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3469 the old syntax may be recovered as follows:
  3470 
  3471   syntax (symbols)
  3472     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3473       (infixl "\\<oplus>" 100)
  3474 
  3475 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3476 
  3477 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3478 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3479 internally;
  3480 
  3481 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3482 changed from A/r to A//r;
  3483 
  3484 * ZF: new treatment of arithmetic (nat & int) may break some old
  3485 proofs;
  3486 
  3487 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3488 rulify -> rule_format, elimify -> elim_format, ...);
  3489 
  3490 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3491 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3492 should have to change intro!! to intro? only); replaced "delrule" by
  3493 "rule del";
  3494 
  3495 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3496 
  3497 * Provers: strengthened force_tac by using new first_best_tac;
  3498 
  3499 * LaTeX document preparation: several changes of isabelle.sty (see
  3500 lib/texinputs);
  3501 
  3502 
  3503 *** Document preparation ***
  3504 
  3505 * formal comments (text blocks etc.) in new-style theories may now
  3506 contain antiquotations of thm/prop/term/typ/text to be presented
  3507 according to latex print mode; concrete syntax is like this:
  3508 @{term[show_types] "f(x) = a + x"};
  3509 
  3510 * isatool mkdir provides easy setup of Isabelle session directories,
  3511 including proper document sources;
  3512 
  3513 * generated LaTeX sources are now deleted after successful run
  3514 (isatool document -c); may retain a copy somewhere else via -D option
  3515 of isatool usedir;
  3516 
  3517 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3518 style files, achieving self-contained LaTeX sources and simplifying
  3519 LaTeX debugging;
  3520 
  3521 * old-style theories now produce (crude) LaTeX output as well;
  3522 
  3523 * browser info session directories are now self-contained (may be put
  3524 on WWW server seperately); improved graphs of nested sessions; removed
  3525 graph for 'all sessions';
  3526 
  3527 * several improvements in isabelle style files; \isabellestyle{it}
  3528 produces fake math mode output; \isamarkupheader is now \section by
  3529 default; see lib/texinputs/isabelle.sty etc.;
  3530 
  3531 
  3532 *** Isar ***
  3533 
  3534 * Isar/Pure: local results and corresponding term bindings are now
  3535 subject to Hindley-Milner polymorphism (similar to ML); this
  3536 accommodates incremental type-inference very nicely;
  3537 
  3538 * Isar/Pure: new derived language element 'obtain' supports
  3539 generalized existence reasoning;
  3540 
  3541 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3542 support accumulation of results, without applying any rules yet;
  3543 useful to collect intermediate results without explicit name
  3544 references, and for use with transitivity rules with more than 2
  3545 premises;
  3546 
  3547 * Isar/Pure: scalable support for case-analysis type proofs: new
  3548 'case' language element refers to local contexts symbolically, as
  3549 produced by certain proof methods; internally, case names are attached
  3550 to theorems as "tags";
  3551 
  3552 * Isar/Pure: theory command 'hide' removes declarations from
  3553 class/type/const name spaces;
  3554 
  3555 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3556 indicate potential overloading;
  3557 
  3558 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3559 
  3560 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3561 "{a,b,c}" instead of {a,b,c};
  3562 
  3563 * Isar/Pure now provides its own version of intro/elim/dest
  3564 attributes; useful for building new logics, but beware of confusion
  3565 with the version in Provers/classical;
  3566 
  3567 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3568 case name 'antecedent';
  3569 
  3570 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3571 to the current context is now done automatically);
  3572 
  3573 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3574 for definining proof methods in ML;
  3575 
  3576 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3577 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3578 most cases, one should have to change intro!! to intro? only);
  3579 replaced "delrule" by "rule del";
  3580 
  3581 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3582 'symmetric' attribute (the latter supercedes [RS sym]);
  3583 
  3584 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3585 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3586 well (including splits);
  3587 
  3588 * Isar/Provers: Simplifier and Classical methods now support all kind
  3589 of modifiers used in the past, including 'cong', 'iff', etc.
  3590 
  3591 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3592 of Simplifier and Classical reasoner);
  3593 
  3594 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3595 now support named cases; major packages (inductive, datatype, primrec,
  3596 recdef) support case names and properly name parameters;
  3597 
  3598 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3599 monotonicity conditions are extracted to be proven at end of
  3600 calculations;
  3601 
  3602 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3603 method anyway;
  3604 
  3605 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3606 split_if split_if_asm; datatype package provides theorems foo.splits =
  3607 foo.split foo.split_asm for each datatype;
  3608 
  3609 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3610 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3611 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3612 use "(cases (simplified))" method in proper proof texts);
  3613 
  3614 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3615 
  3616 * Isar: names of theorems etc. may be natural numbers as well;
  3617 
  3618 * Isar: 'pr' command: optional arguments for goals_limit and
  3619 ProofContext.prems_limit; no longer prints theory contexts, but only
  3620 proof states;
  3621 
  3622 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3623 additional print modes to be specified; e.g. "pr(latex)" will print
  3624 proof state according to the Isabelle LaTeX style;
  3625 
  3626 * Isar: improved support for emulating tactic scripts, including proof
  3627 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3628 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3629 (for HOL datatypes);
  3630 
  3631 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3632 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3633 'proof method scripts' have to be in depth-first order;
  3634 
  3635 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3636 
  3637 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3638 should instead use individual commands for printing items
  3639 (print_commands, print_methods etc.);
  3640 
  3641 * Isar: added 'nothing' --- the empty list of theorems;
  3642 
  3643 
  3644 *** HOL ***
  3645 
  3646 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3647 corresponding virtual machine and a specification of its bytecode
  3648 verifier and a lightweight bytecode verifier, including proofs of
  3649 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3650 Cornelia Pusch (see also the homepage of project Bali at
  3651 http://isabelle.in.tum.de/Bali/);
  3652 
  3653 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3654 Clemens Ballarin;
  3655 
  3656 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3657 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3658 Rasmussen;
  3659 
  3660 * HOL/Lattice: fundamental concepts of lattice theory and order
  3661 structures, including duals, properties of bounds versus algebraic
  3662 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3663 Theorem for complete lattices etc.; may also serve as a demonstration
  3664 for abstract algebraic reasoning using axiomatic type classes, and
  3665 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3666 
  3667 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3668 von Oheimb;
  3669 
  3670 * HOL/IMPP: extension of IMP with local variables and mutually
  3671 recursive procedures, by David von Oheimb;
  3672 
  3673 * HOL/Lambda: converted into new-style theory and document;
  3674 
  3675 * HOL/ex/Multiquote: example of multiple nested quotations and
  3676 anti-quotations -- basically a generalized version of de-Bruijn
  3677 representation; very useful in avoiding lifting of operations;
  3678 
  3679 * HOL/record: added general record equality rule to simpset; fixed
  3680 select-update simplification procedure to handle extended records as
  3681 well; admit "r" as field name;
  3682 
  3683 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3684 other numeric types and also as the identity of groups, rings, etc.;
  3685 
  3686 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3687 Types nat and int belong to this axclass;
  3688 
  3689 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3690    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3691    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3692   two terms #m*u and #n*u are replaced by #(m+n)*u
  3693     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3694   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3695     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3696 
  3697 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3698 powerful prover for predicate logic but knows nothing of clasets; see
  3699 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3700 
  3701 * HOL: new version of "case_tac" subsumes both boolean case split and
  3702 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3703 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3704 
  3705 * HOL: simplification no longer dives into case-expressions: only the
  3706 selector expression is simplified, but not the remaining arms; to
  3707 enable full simplification of case-expressions for datatype t, you may
  3708 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3709 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3710 
  3711 * HOL/recdef: the recursion equations generated by 'recdef' for
  3712 function 'f' are now called f.simps instead of f.rules; if all
  3713 termination conditions are proved automatically, these simplification
  3714 rules are added to the simpset, as in primrec; rules may be named
  3715 individually as well, resulting in a separate list of theorems for
  3716 each equation;
  3717 
  3718 * HOL/While is a new theory that provides a while-combinator. It
  3719 permits the definition of tail-recursive functions without the
  3720 provision of a termination measure. The latter is necessary once the
  3721 invariant proof rule for while is applied.
  3722 
  3723 * HOL: new (overloaded) notation for the set of elements below/above
  3724 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3725 
  3726 * HOL: theorems impI, allI, ballI bound as "strip";
  3727 
  3728 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3729 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3730 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3731 
  3732 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3733 
  3734 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3735 main HOL, but was unused);
  3736 
  3737 * HOL: fewer consts declared as global (e.g. have to refer to
  3738 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3739 
  3740 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3741 in case of overlap with user translations (e.g. judgements over
  3742 tuples); (note that the underlying logical represenation is still
  3743 bogus);
  3744 
  3745 
  3746 *** ZF ***
  3747 
  3748 * ZF: simplification automatically cancels common terms in arithmetic
  3749 expressions over nat and int;
  3750 
  3751 * ZF: new treatment of nat to minimize type-checking: all operators
  3752 coerce their operands to a natural number using the function natify,
  3753 making the algebraic laws unconditional;
  3754 
  3755 * ZF: as above, for int: operators coerce their operands to an integer
  3756 using the function intify;
  3757 
  3758 * ZF: the integer library now contains many of the usual laws for the
  3759 orderings, including $<=, and monotonicity laws for $+ and $*;
  3760 
  3761 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3762 simplification;
  3763 
  3764 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3765 to the simplifier and classical reasoner simultaneously;
  3766 
  3767 
  3768 *** General ***
  3769 
  3770 * Provers: blast_tac now handles actual object-logic rules as
  3771 assumptions; note that auto_tac uses blast_tac internally as well;
  3772 
  3773 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3774 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3775 
  3776 * Provers: delrules now handles destruct rules as well (no longer need
  3777 explicit make_elim);
  3778 
  3779 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3780   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3781 use instead the strong form,
  3782   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3783 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3784 from destruct-rules;
  3785 
  3786 * Provers: Simplifier.easy_setup provides a fast path to basic
  3787 Simplifier setup for new object-logics;
  3788 
  3789 * Pure: AST translation rules no longer require constant head on LHS;
  3790 
  3791 * Pure: improved name spaces: ambiguous output is qualified; support
  3792 for hiding of names;
  3793 
  3794 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3795 XSYMBOL_HOME; no longer need to do manual configuration in most
  3796 situations;
  3797 
  3798 * system: compression of ML heaps images may now be controlled via -c
  3799 option of isabelle and isatool usedir (currently only observed by
  3800 Poly/ML);
  3801 
  3802 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3803 useful for remote X11);
  3804 
  3805 * system: provide TAGS file for Isabelle sources;
  3806 
  3807 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3808 order;
  3809 
  3810 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3811 timing flag supersedes proof_timing and Toplevel.trace;
  3812 
  3813 * ML: new combinators |>> and |>>> for incremental transformations
  3814 with secondary results (e.g. certain theory extensions):
  3815 
  3816 * ML: PureThy.add_defs gets additional argument to indicate potential
  3817 overloading (usually false);
  3818 
  3819 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3820 results;
  3821 
  3822 
  3823 
  3824 New in Isabelle99 (October 1999)
  3825 --------------------------------
  3826 
  3827 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3828 
  3829 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3830 are no longer simplified.  (This allows the simplifier to unfold recursive
  3831 functional programs.)  To restore the old behaviour, declare
  3832 
  3833     Delcongs [if_weak_cong];
  3834 
  3835 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3836 complement;
  3837 
  3838 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3839 
  3840 * HOL/datatype: mutual_induct_tac no longer exists --
  3841   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3842 
  3843 * HOL/typedef: fixed type inference for representing set; type
  3844 arguments now have to occur explicitly on the rhs as type constraints;
  3845 
  3846 * ZF: The con_defs part of an inductive definition may no longer refer
  3847 to constants declared in the same theory;
  3848 
  3849 * HOL, ZF: the function mk_cases, generated by the inductive
  3850 definition package, has lost an argument.  To simplify its result, it
  3851 uses the default simpset instead of a supplied list of theorems.
  3852 
  3853 * HOL/List: the constructors of type list are now Nil and Cons;
  3854 
  3855 * Simplifier: the type of the infix ML functions
  3856         setSSolver addSSolver setSolver addSolver
  3857 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3858 for packaging solvers. A solver is created via
  3859         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3860 where the string argument is only a comment.
  3861 
  3862 
  3863 *** Proof tools ***
  3864 
  3865 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3866 decision procedure for linear arithmetic. Currently it is used for
  3867 types `nat', `int', and `real' in HOL (see below); it can, should and
  3868 will be instantiated for other types and logics as well.
  3869 
  3870 * The simplifier now accepts rewrite rules with flexible heads, eg
  3871      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3872   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3873   matching.
  3874 
  3875 
  3876 *** General ***
  3877 
  3878 * New Isabelle/Isar subsystem provides an alternative to traditional
  3879 tactical theorem proving; together with the ProofGeneral/isar user
  3880 interface it offers an interactive environment for developing human
  3881 readable proof documents (Isar == Intelligible semi-automated
  3882 reasoning); for further information see isatool doc isar-ref,
  3883 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3884 
  3885 * improved and simplified presentation of theories: better HTML markup
  3886 (including colors), graph views in several sizes; isatool usedir now
  3887 provides a proper interface for user theories (via -P option); actual
  3888 document preparation based on (PDF)LaTeX is available as well (for
  3889 new-style theories only); see isatool doc system for more information;
  3890 
  3891 * native support for Proof General, both for classic Isabelle and
  3892 Isabelle/Isar;
  3893 
  3894 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3895 using the graph browser tool;
  3896 
  3897 * Isabelle manuals now also available as PDF;
  3898 
  3899 * theory loader rewritten from scratch (may not be fully
  3900 bug-compatible); old loadpath variable has been replaced by show_path,
  3901 add_path, del_path, reset_path functions; new operations such as
  3902 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3903 isatool doc ref);
  3904 
  3905 * improved isatool install: option -k creates KDE application icon,
  3906 option -p DIR installs standalone binaries;
  3907 
  3908 * added ML_PLATFORM setting (useful for cross-platform installations);
  3909 more robust handling of platform specific ML images for SML/NJ;
  3910 
  3911 * the settings environment is now statically scoped, i.e. it is never
  3912 created again in sub-processes invoked from isabelle, isatool, or
  3913 Isabelle;
  3914 
  3915 * path element specification '~~' refers to '$ISABELLE_HOME';
  3916 
  3917 * in locales, the "assumes" and "defines" parts may be omitted if
  3918 empty;
  3919 
  3920 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3921 long arrows);
  3922 
  3923 * new print_mode "HTML";
  3924 
  3925 * new flag show_tags controls display of tags of theorems (which are
  3926 basically just comments that may be attached by some tools);
  3927 
  3928 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3929 mode and goal output format:
  3930 
  3931 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3932 244c244
  3933 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3934 ---
  3935 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3936 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3937 181c181
  3938 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3939 ---
  3940 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3941 
  3942 * function bind_thms stores lists of theorems (cf. bind_thm);
  3943 
  3944 * new shorthand tactics ftac, eatac, datac, fatac;
  3945 
  3946 * qed (and friends) now accept "" as result name; in that case the
  3947 theorem is not stored, but proper checks and presentation of the
  3948 result still apply;
  3949 
  3950 * theorem database now also indexes constants "Trueprop", "all",
  3951 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3952 
  3953 
  3954 *** HOL ***
  3955 
  3956 ** HOL arithmetic **
  3957 
  3958 * There are now decision procedures for linear arithmetic over nat and
  3959 int:
  3960 
  3961 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3962 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3963 are treated as atomic; subformulae not involving type `nat' or `int'
  3964 are ignored; quantified subformulae are ignored unless they are
  3965 positive universal or negative existential. The tactic has to be
  3966 invoked by hand and can be a little bit slow. In particular, the
  3967 running time is exponential in the number of occurrences of `min' and
  3968 `max', and `-' on `nat'.
  3969 
  3970 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3971 (negated) (in)equalities among the premises and the conclusion into
  3972 account (i.e. no compound formulae) and does not know about `min' and
  3973 `max', and `-' on `nat'. It is fast and is used automatically by the
  3974 simplifier.
  3975 
  3976 NB: At the moment, these decision procedures do not cope with mixed
  3977 nat/int formulae where the two parts interact, such as `m < n ==>
  3978 int(m) < int(n)'.
  3979 
  3980 * HOL/Numeral provides a generic theory of numerals (encoded
  3981 efficiently as bit strings); setup for types nat/int/real is in place;
  3982 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3983 int, existing theories and proof scripts may require a few additional
  3984 type constraints;
  3985 
  3986 * integer division and remainder can now be performed on constant
  3987 arguments;
  3988 
  3989 * many properties of integer multiplication, division and remainder
  3990 are now available;
  3991 
  3992 * An interface to the Stanford Validity Checker (SVC) is available through the
  3993 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3994 are proved automatically.  SVC must be installed separately, and its results
  3995 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3996 invocation of the underlying oracle).  For SVC see
  3997   http://verify.stanford.edu/SVC
  3998 
  3999 * IsaMakefile: the HOL-Real target now builds an actual image;
  4000 
  4001 
  4002 ** HOL misc **
  4003 
  4004 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4005 (in Isabelle/Isar) -- by Gertrud Bauer;
  4006 
  4007 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4008 analysis for assembly languages with subtypes;
  4009 
  4010 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4011 -- avoids syntactic ambiguities and treats state, transition, and
  4012 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4013 changed syntax and (many) tactics;
  4014 
  4015 * HOL/inductive: Now also handles more general introduction rules such
  4016   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4017   theorems are now maintained within the theory (maintained via the
  4018   "mono" attribute);
  4019 
  4020 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4021   (using function types) such as
  4022 
  4023   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4024 
  4025 * HOL/record: record_simproc (part of the default simpset) takes care
  4026 of selectors applied to updated records; record_split_tac is no longer
  4027 part of the default claset; update_defs may now be removed from the
  4028 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4029 
  4030   claset_ref () := claset() addSWrapper record_split_wrapper;
  4031   Delsimprocs [record_simproc]
  4032 
  4033 * HOL/typedef: fixed type inference for representing set; type
  4034 arguments now have to occur explicitly on the rhs as type constraints;
  4035 
  4036 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4037 names rather than an ML expression;
  4038 
  4039 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4040 supplied later.  Program schemes can be defined, such as
  4041     "While B C s = (if B s then While B C (C s) else s)"
  4042 where the well-founded relation can be chosen after B and C have been given.
  4043 
  4044 * HOL/List: the constructors of type list are now Nil and Cons;
  4045 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4046 course, ML tools referring to List.list.op # etc. have to be adapted;
  4047 
  4048 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4049 disabled by default; run isabelle with option -m HOL to get back to
  4050 the original Gordon/HOL-style output;
  4051 
  4052 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4053 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4054 
  4055 * HOL basic syntax simplified (more orthogonal): all variants of
  4056 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4057 Eps operator is provided as well: "SOME x. P[x]";
  4058 
  4059 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4060 
  4061 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4062 thus available for user theories;
  4063 
  4064 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4065 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4066 time;
  4067 
  4068 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4069 several times and then mp;
  4070 
  4071 
  4072 *** LK ***
  4073 
  4074 * the notation <<...>> is now available as a notation for sequences of
  4075 formulas;
  4076 
  4077 * the simplifier is now installed
  4078 
  4079 * the axiom system has been generalized (thanks to Soren Heilmann)
  4080 
  4081 * the classical reasoner now has a default rule database
  4082 
  4083 
  4084 *** ZF ***
  4085 
  4086 * new primrec section allows primitive recursive functions to be given
  4087 directly (as in HOL) over datatypes and the natural numbers;
  4088 
  4089 * new tactics induct_tac and exhaust_tac for induction (or case
  4090 analysis) over datatypes and the natural numbers;
  4091 
  4092 * the datatype declaration of type T now defines the recursor T_rec;
  4093 
  4094 * simplification automatically does freeness reasoning for datatype
  4095 constructors;
  4096 
  4097 * automatic type-inference, with AddTCs command to insert new
  4098 type-checking rules;
  4099 
  4100 * datatype introduction rules are now added as Safe Introduction rules
  4101 to the claset;
  4102 
  4103 * the syntax "if P then x else y" is now available in addition to
  4104 if(P,x,y);
  4105 
  4106 
  4107 *** Internal programming interfaces ***
  4108 
  4109 * tuned simplifier trace output; new flag debug_simp;
  4110 
  4111 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4112 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4113 
  4114 * AxClass.axclass_tac lost the theory argument;
  4115 
  4116 * tuned current_goals_markers semantics: begin / end goal avoids
  4117 printing empty lines;
  4118 
  4119 * removed prs and prs_fn hook, which was broken because it did not
  4120 include \n in its semantics, forcing writeln to add one
  4121 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4122 string -> unit if you really want to output text without newline;
  4123 
  4124 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4125 plain output, interface builders may have to enable 'isabelle_font'
  4126 mode to get Isabelle font glyphs as before;
  4127 
  4128 * refined token_translation interface; INCOMPATIBILITY: output length
  4129 now of type real instead of int;
  4130 
  4131 * theory loader actions may be traced via new ThyInfo.add_hook
  4132 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4133 your own database of information attached to *whole* theories -- as
  4134 opposed to intra-theory data slots offered via TheoryDataFun;
  4135 
  4136 * proper handling of dangling sort hypotheses (at last!);
  4137 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4138 extra sort hypotheses that can be witnessed from the type signature;
  4139 the force_strip_shyps flag is gone, any remaining shyps are simply
  4140 left in the theorem (with a warning issued by strip_shyps_warning);
  4141 
  4142 
  4143 
  4144 New in Isabelle98-1 (October 1998)
  4145 ----------------------------------
  4146 
  4147 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4148 
  4149 * several changes of automated proof tools;
  4150 
  4151 * HOL: major changes to the inductive and datatype packages, including
  4152 some minor incompatibilities of theory syntax;
  4153 
  4154 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4155 called `inj_on';
  4156 
  4157 * HOL: removed duplicate thms in Arith:
  4158   less_imp_add_less  should be replaced by  trans_less_add1
  4159   le_imp_add_le      should be replaced by  trans_le_add1
  4160 
  4161 * HOL: unary minus is now overloaded (new type constraints may be
  4162 required);
  4163 
  4164 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4165 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4166 now taken as an integer constant.
  4167 
  4168 * Pure: ML function 'theory_of' renamed to 'theory';
  4169 
  4170 
  4171 *** Proof tools ***
  4172 
  4173 * Simplifier:
  4174   1. Asm_full_simp_tac is now more aggressive.
  4175      1. It will sometimes reorient premises if that increases their power to
  4176         simplify.
  4177      2. It does no longer proceed strictly from left to right but may also
  4178         rotate premises to achieve further simplification.
  4179      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4180      old Asm_full_simp_tac in that it does not rotate premises.
  4181   2. The simplifier now knows a little bit about nat-arithmetic.
  4182 
  4183 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4184 allows for selected deletion of wrappers, by introduction of names for
  4185 wrapper functionals.  This implies that addbefore, addSbefore,
  4186 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4187 and that adding two tactics with the same name overwrites the first
  4188 one (emitting a warning).
  4189   type wrapper = (int -> tactic) -> (int -> tactic)
  4190   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4191   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4192   delWrapper, delSWrapper: claset *  string            -> claset
  4193   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4194 
  4195 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4196 semantics; addbefore now affects only the unsafe part of step_tac
  4197 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4198 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4199 by Force_tac;
  4200 
  4201 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4202 compWrapper; added safe wrapper (and access functions for it);
  4203 
  4204 * HOL/split_all_tac is now much faster and fails if there is nothing
  4205 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4206 and the names of the automatically generated variables have changed.
  4207 split_all_tac has moved within claset() from unsafe wrappers to safe
  4208 wrappers, which means that !!-bound variables are split much more
  4209 aggressively, and safe_tac and clarify_tac now split such variables.
  4210 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4211 Note: the same holds for record_split_tac, which does the job of
  4212 split_all_tac for record fields.
  4213 
  4214 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4215 permanently to the default simpset using Addsplits just like
  4216 Addsimps. They can be removed via Delsplits just like
  4217 Delsimps. Lower-case versions are also available.
  4218 
  4219 * HOL/Simplifier: The rule split_if is now part of the default
  4220 simpset. This means that the simplifier will eliminate all occurrences
  4221 of if-then-else in the conclusion of a goal. To prevent this, you can
  4222 either remove split_if completely from the default simpset by
  4223 `Delsplits [split_if]' or remove it in a specific call of the
  4224 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4225 other case splitting rules to/from the default simpset: every datatype
  4226 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4227 t is the name of the datatype).
  4228 
  4229 * Classical reasoner / Simplifier combination: new force_tac (and
  4230 derivatives Force_tac, force) combines rewriting and classical
  4231 reasoning (and whatever other tools) similarly to auto_tac, but is
  4232 aimed to solve the given subgoal completely.
  4233 
  4234 
  4235 *** General ***
  4236 
  4237 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4238 and `goalw': the theory is no longer needed as an explicit argument -
  4239 the current theory context is used; assumptions are no longer returned
  4240 at the ML-level unless one of them starts with ==> or !!; it is
  4241 recommended to convert to these new commands using isatool fixgoal
  4242 (backup your sources first!);
  4243 
  4244 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4245 the current theory context, and 'theory' to lookup stored theories;
  4246 
  4247 * new theory section 'locale' for declaring constants, assumptions and
  4248 definitions that have local scope;
  4249 
  4250 * new theory section 'nonterminals' for purely syntactic types;
  4251 
  4252 * new theory section 'setup' for generic ML setup functions
  4253 (e.g. package initialization);
  4254 
  4255 * the distribution now includes Isabelle icons: see
  4256 lib/logo/isabelle-{small,tiny}.xpm;
  4257 
  4258 * isatool install - install binaries with absolute references to
  4259 ISABELLE_HOME/bin;
  4260 
  4261 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4262 
  4263 * print mode 'emacs' reserved for Isamode;
  4264 
  4265 * support multiple print (ast) translations per constant name;
  4266 
  4267 * theorems involving oracles are now printed with a suffixed [!];
  4268 
  4269 
  4270 *** HOL ***
  4271 
  4272 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4273 
  4274 * HOL/inductive package reorganized and improved: now supports mutual
  4275 definitions such as
  4276 
  4277   inductive EVEN ODD
  4278     intrs
  4279       null "0 : EVEN"
  4280       oddI "n : EVEN ==> Suc n : ODD"
  4281       evenI "n : ODD ==> Suc n : EVEN"
  4282 
  4283 new theorem list "elims" contains an elimination rule for each of the
  4284 recursive sets; inductive definitions now handle disjunctive premises
  4285 correctly (also ZF);
  4286 
  4287 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4288 "mutual_induct" no longer exists - the induction rule is always
  4289 contained in "induct";
  4290 
  4291 
  4292 * HOL/datatype package re-implemented and greatly improved: now
  4293 supports mutually recursive datatypes such as
  4294 
  4295   datatype
  4296     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4297             | SUM ('a aexp) ('a aexp)
  4298             | DIFF ('a aexp) ('a aexp)
  4299             | NUM 'a
  4300   and
  4301     'a bexp = LESS ('a aexp) ('a aexp)
  4302             | AND ('a bexp) ('a bexp)
  4303             | OR ('a bexp) ('a bexp)
  4304 
  4305 as well as indirectly recursive datatypes such as
  4306 
  4307   datatype
  4308     ('a, 'b) term = Var 'a
  4309                   | App 'b ((('a, 'b) term) list)
  4310 
  4311 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4312 induction on mutually / indirectly recursive datatypes.
  4313 
  4314 Primrec equations are now stored in theory and can be accessed via
  4315 <function_name>.simps.
  4316 
  4317 INCOMPATIBILITIES:
  4318 
  4319   - Theories using datatypes must now have theory Datatype as an
  4320     ancestor.
  4321   - The specific <typename>.induct_tac no longer exists - use the
  4322     generic induct_tac instead.
  4323   - natE has been renamed to nat.exhaust - use exhaust_tac
  4324     instead of res_inst_tac ... natE. Note that the variable
  4325     names in nat.exhaust differ from the names in natE, this
  4326     may cause some "fragile" proofs to fail.
  4327   - The theorems split_<typename>_case and split_<typename>_case_asm
  4328     have been renamed to <typename>.split and <typename>.split_asm.
  4329   - Since default sorts of type variables are now handled correctly,
  4330     some datatype definitions may have to be annotated with explicit
  4331     sort constraints.
  4332   - Primrec definitions no longer require function name and type
  4333     of recursive argument.
  4334 
  4335 Consider using isatool fixdatatype to adapt your theories and proof
  4336 scripts to the new package (backup your sources first!).
  4337 
  4338 
  4339 * HOL/record package: considerably improved implementation; now
  4340 includes concrete syntax for record types, terms, updates; theorems
  4341 for surjective pairing and splitting !!-bound record variables; proof
  4342 support is as follows:
  4343 
  4344   1) standard conversions (selectors or updates applied to record
  4345 constructor terms) are part of the standard simpset;
  4346 
  4347   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4348 made part of standard simpset and claset via addIffs;
  4349 
  4350   3) a tactic for record field splitting (record_split_tac) is part of
  4351 the standard claset (addSWrapper);
  4352 
  4353 To get a better idea about these rules you may retrieve them via
  4354 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4355 the name of your record type.
  4356 
  4357 The split tactic 3) conceptually simplifies by the following rule:
  4358 
  4359   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4360 
  4361 Thus any record variable that is bound by meta-all will automatically
  4362 blow up into some record constructor term, consequently the
  4363 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4364 solve record problems automatically.
  4365 
  4366 
  4367 * reorganized the main HOL image: HOL/Integ and String loaded by
  4368 default; theory Main includes everything;
  4369 
  4370 * automatic simplification of integer sums and comparisons, using cancellation;
  4371 
  4372 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4373 
  4374 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4375 
  4376 * many new identities for unions, intersections, set difference, etc.;
  4377 
  4378 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4379 called split_if, split_split, split_sum_case and split_nat_case (to go
  4380 with add/delsplits);
  4381 
  4382 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4383 (?x::unit) = (); this is made part of the default simpset, which COULD
  4384 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4385 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4386 unit_abs_eta_conv is added in order to counter the effect of
  4387 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4388 %u.f();
  4389 
  4390 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4391 makes more sense);
  4392 
  4393 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4394   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4395   disjointness reasoning but breaking a few old proofs.
  4396 
  4397 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4398 to 'converse' from 'inverse' (for compatibility with ZF and some
  4399 literature);
  4400 
  4401 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4402 the well-founded relation;
  4403 
  4404 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4405     Compl A.  The "Compl" syntax remains available as input syntax for this
  4406     release ONLY.
  4407 
  4408 * HOL/Update: new theory of function updates:
  4409     f(a:=b) == %x. if x=a then b else f x
  4410 may also be iterated as in f(a:=b,c:=d,...);
  4411 
  4412 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4413 
  4414 * HOL/List:
  4415   - new function list_update written xs[i:=v] that updates the i-th
  4416     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4417   - new function `upt' written [i..j(] which generates the list
  4418     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4419     bound write [i..j], which is a shorthand for [i..j+1(].
  4420   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4421 
  4422 * HOL/Arith:
  4423   - removed 'pred' (predecessor) function;
  4424   - generalized some theorems about n-1;
  4425   - many new laws about "div" and "mod";
  4426   - new laws about greatest common divisors (see theory ex/Primes);
  4427 
  4428 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4429 instead of "inverse";
  4430 
  4431 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4432   of the multiset ordering;
  4433 
  4434 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4435   (not included by default);
  4436 
  4437 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4438 
  4439 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4440   programs, i.e. different program variables may have different types.
  4441 
  4442 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4443   [previously, this check worked only if the rewrite rule was unconditional]
  4444   Now rew can involve either definitions or equalities (either == or =).
  4445 
  4446 
  4447 *** ZF ***
  4448 
  4449 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4450   only the theorems proved on ZF.ML;
  4451 
  4452 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4453   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4454   disjointness reasoning but breaking a few old proofs.
  4455 
  4456 * ZF/Update: new theory of function updates
  4457     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4458   may also be iterated as in f(a:=b,c:=d,...);
  4459 
  4460 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4461 
  4462 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4463   [previously, this check worked only if the rewrite rule was unconditional]
  4464   Now rew can involve either definitions or equalities (either == or =).
  4465 
  4466 * case_tac provided for compatibility with HOL
  4467     (like the old excluded_middle_tac, but with subgoals swapped)
  4468 
  4469 
  4470 *** Internal programming interfaces ***
  4471 
  4472 * Pure: several new basic modules made available for general use, see
  4473 also src/Pure/README;
  4474 
  4475 * improved the theory data mechanism to support encapsulation (data
  4476 kind name replaced by private Object.kind, acting as authorization
  4477 key); new type-safe user interface via functor TheoryDataFun; generic
  4478 print_data function becomes basically useless;
  4479 
  4480 * removed global_names compatibility flag -- all theory declarations
  4481 are qualified by default;
  4482 
  4483 * module Pure/Syntax now offers quote / antiquote translation
  4484 functions (useful for Hoare logic etc. with implicit dependencies);
  4485 see HOL/ex/Antiquote for an example use;
  4486 
  4487 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4488 cterm -> thm;
  4489 
  4490 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4491 subgoal;
  4492 
  4493 * Display.print_goals function moved to Locale.print_goals;
  4494 
  4495 * standard print function for goals supports current_goals_markers
  4496 variable for marking begin of proof, end of proof, start of goal; the
  4497 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4498 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4499 for example;
  4500 
  4501 
  4502 
  4503 New in Isabelle98 (January 1998)
  4504 --------------------------------
  4505 
  4506 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4507 
  4508 * changed lexical syntax of terms / types: dots made part of long
  4509 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4510 
  4511 * simpset (and claset) reference variable replaced by functions
  4512 simpset / simpset_ref;
  4513 
  4514 * no longer supports theory aliases (via merge) and non-trivial
  4515 implicit merge of thms' signatures;
  4516 
  4517 * most internal names of constants changed due to qualified names;
  4518 
  4519 * changed Pure/Sequence interface (see Pure/seq.ML);
  4520 
  4521 
  4522 *** General Changes ***
  4523 
  4524 * hierachically structured name spaces (for consts, types, axms, thms
  4525 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4526 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4527 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4528 long_names for fully qualified output names; NOTE: ML programs
  4529 (special tactics, packages etc.) referring to internal names may have
  4530 to be adapted to cope with fully qualified names; in case of severe
  4531 backward campatibility problems try setting 'global_names' at compile
  4532 time to have enrything declared within a flat name space; one may also
  4533 fine tune name declarations in theories via the 'global' and 'local'
  4534 section;
  4535 
  4536 * reimplemented the implicit simpset and claset using the new anytype
  4537 data filed in signatures; references simpset:simpset ref etc. are
  4538 replaced by functions simpset:unit->simpset and
  4539 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4540 to patch your ML files accordingly;
  4541 
  4542 * HTML output now includes theory graph data for display with Java
  4543 applet or isatool browser; data generated automatically via isatool
  4544 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4545 
  4546 * defs may now be conditional; improved rewrite_goals_tac to handle
  4547 conditional equations;
  4548 
  4549 * defs now admits additional type arguments, using TYPE('a) syntax;
  4550 
  4551 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4552 creates a new theory node; implicit merge of thms' signatures is
  4553 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4554 transfer:theory->thm->thm in (rare) cases;
  4555 
  4556 * improved handling of draft signatures / theories; draft thms (and
  4557 ctyps, cterms) are automatically promoted to real ones;
  4558 
  4559 * slightly changed interfaces for oracles: admit many per theory, named
  4560 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4561 
  4562 * print_goals: optional output of const types (set show_consts and
  4563 show_types);
  4564 
  4565 * improved output of warnings (###) and errors (***);
  4566 
  4567 * subgoal_tac displays a warning if the new subgoal has type variables;
  4568 
  4569 * removed old README and Makefiles;
  4570 
  4571 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4572 
  4573 * removed obsolete init_pps and init_database;
  4574 
  4575 * deleted the obsolete tactical STATE, which was declared by
  4576     fun STATE tacfun st = tacfun st st;
  4577 
  4578 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4579 (which abbreviates $HOME);
  4580 
  4581 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4582 use isatool fixseq to adapt your ML programs (this works for fully
  4583 qualified references to the Sequence structure only!);
  4584 
  4585 * use_thy no longer requires writable current directory; it always
  4586 reloads .ML *and* .thy file, if either one is out of date;
  4587 
  4588 
  4589 *** Classical Reasoner ***
  4590 
  4591 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4592 tactics that use classical reasoning to simplify a subgoal without
  4593 splitting it into several subgoals;
  4594 
  4595 * Safe_tac: like safe_tac but uses the default claset;
  4596 
  4597 
  4598 *** Simplifier ***
  4599 
  4600 * added simplification meta rules:
  4601     (asm_)(full_)simplify: simpset -> thm -> thm;
  4602 
  4603 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4604 logics (again);
  4605 
  4606 * added prems argument to simplification procedures;
  4607 
  4608 * HOL, FOL, ZF: added infix function `addsplits':
  4609   instead of `<simpset> setloop (split_tac <thms>)'
  4610   you can simply write `<simpset> addsplits <thms>'
  4611 
  4612 
  4613 *** Syntax ***
  4614 
  4615 * TYPE('a) syntax for type reflection terms;
  4616 
  4617 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4618 
  4619 * pretty printer: changed order of mixfix annotation preference (again!);
  4620 
  4621 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4622 
  4623 
  4624 *** HOL ***
  4625 
  4626 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4627   with `addloop' of the simplifier to faciliate case splitting in premises.
  4628 
  4629 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4630 
  4631 * HOL/Auth: new protocol proofs including some for the Internet
  4632   protocol TLS;
  4633 
  4634 * HOL/Map: new theory of `maps' a la VDM;
  4635 
  4636 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4637 cancelling out common nat summands from =, <, <= (in)equalities, or
  4638 differences; simplification procedures nat_cancel_factor for
  4639 cancelling common factor from =, <, <= (in)equalities over natural
  4640 sums; nat_cancel contains both kinds of procedures, it is installed by
  4641 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4642 
  4643 * HOL/simplifier: terms of the form
  4644   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4645   are rewritten to
  4646   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4647   and those of the form
  4648   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4649   are rewritten to
  4650   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4651 
  4652 * HOL/datatype
  4653   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4654 
  4655   P(t_case f1 ... fn x) =
  4656      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4657         ...
  4658        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4659      )
  4660 
  4661   and a theorem `split_t_case_asm' of the form
  4662 
  4663   P(t_case f1 ... fn x) =
  4664     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4665         ...
  4666        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4667      )
  4668   which can be added to a simpset via `addsplits'. The existing theorems
  4669   expand_list_case and expand_option_case have been renamed to
  4670   split_list_case and split_option_case.
  4671 
  4672 * HOL/Arithmetic:
  4673   - `pred n' is automatically converted to `n-1'.
  4674     Users are strongly encouraged not to use `pred' any longer,
  4675     because it will disappear altogether at some point.
  4676   - Users are strongly encouraged to write "0 < n" rather than
  4677     "n ~= 0". Theorems and proof tools have been modified towards this
  4678     `standard'.
  4679 
  4680 * HOL/Lists:
  4681   the function "set_of_list" has been renamed "set" (and its theorems too);
  4682   the function "nth" now takes its arguments in the reverse order and
  4683   has acquired the infix notation "!" as in "xs!n".
  4684 
  4685 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4686 
  4687 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4688   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4689 
  4690 * HOL/record: extensible records with schematic structural subtyping
  4691 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4692 still lacks various theorems and concrete record syntax;
  4693 
  4694 
  4695 *** HOLCF ***
  4696 
  4697 * removed "axioms" and "generated by" sections;
  4698 
  4699 * replaced "ops" section by extended "consts" section, which is capable of
  4700   handling the continuous function space "->" directly;
  4701 
  4702 * domain package:
  4703   . proves theorems immediately and stores them in the theory,
  4704   . creates hierachical name space,
  4705   . now uses normal mixfix annotations (instead of cinfix...),
  4706   . minor changes to some names and values (for consistency),
  4707   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4708   . separator between mutual domain defs: changed "," to "and",
  4709   . improved handling of sort constraints;  now they have to
  4710     appear on the left-hand side of the equations only;
  4711 
  4712 * fixed LAM <x,y,zs>.b syntax;
  4713 
  4714 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4715 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4716 
  4717 
  4718 *** FOL and ZF ***
  4719 
  4720 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4721   with `addloop' of the simplifier to faciliate case splitting in premises.
  4722 
  4723 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4724 in HOL, they strip ALL and --> from proved theorems;
  4725 
  4726 
  4727 
  4728 New in Isabelle94-8 (May 1997)
  4729 ------------------------------
  4730 
  4731 *** General Changes ***
  4732 
  4733 * new utilities to build / run / maintain Isabelle etc. (in parts
  4734 still somewhat experimental); old Makefiles etc. still functional;
  4735 
  4736 * new 'Isabelle System Manual';
  4737 
  4738 * INSTALL text, together with ./configure and ./build scripts;
  4739 
  4740 * reimplemented type inference for greater efficiency, better error
  4741 messages and clean internal interface;
  4742 
  4743 * prlim command for dealing with lots of subgoals (an easier way of
  4744 setting goals_limit);
  4745 
  4746 
  4747 *** Syntax ***
  4748 
  4749 * supports alternative (named) syntax tables (parser and pretty
  4750 printer); internal interface is provided by add_modesyntax(_i);
  4751 
  4752 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4753 be used in conjunction with the Isabelle symbol font; uses the
  4754 "symbols" syntax table;
  4755 
  4756 * added token_translation interface (may translate name tokens in
  4757 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4758 the current print_mode); IMPORTANT: user print translation functions
  4759 are responsible for marking newly introduced bounds
  4760 (Syntax.mark_boundT);
  4761 
  4762 * token translations for modes "xterm" and "xterm_color" that display
  4763 names in bold, underline etc. or colors (which requires a color
  4764 version of xterm);
  4765 
  4766 * infixes may now be declared with names independent of their syntax;
  4767 
  4768 * added typed_print_translation (like print_translation, but may
  4769 access type of constant);
  4770 
  4771 
  4772 *** Classical Reasoner ***
  4773 
  4774 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4775 some limitations.  Blast_tac...
  4776   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4777   + ignores elimination rules that don't have the correct format
  4778         (the conclusion MUST be a formula variable)
  4779   + ignores types, which can make HOL proofs fail
  4780   + rules must not require higher-order unification, e.g. apply_type in ZF
  4781     [message "Function Var's argument not a bound variable" relates to this]
  4782   + its proof strategy is more general but can actually be slower
  4783 
  4784 * substitution with equality assumptions no longer permutes other
  4785 assumptions;
  4786 
  4787 * minor changes in semantics of addafter (now called addaltern); renamed
  4788 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4789 (and access functions for it);
  4790 
  4791 * improved combination of classical reasoner and simplifier:
  4792   + functions for handling clasimpsets
  4793   + improvement of addss: now the simplifier is called _after_ the
  4794     safe steps.
  4795   + safe variant of addss called addSss: uses safe simplifications
  4796     _during_ the safe steps. It is more complete as it allows multiple
  4797     instantiations of unknowns (e.g. with slow_tac).
  4798 
  4799 *** Simplifier ***
  4800 
  4801 * added interface for simplification procedures (functions that
  4802 produce *proven* rewrite rules on the fly, depending on current
  4803 redex);
  4804 
  4805 * ordering on terms as parameter (used for ordered rewriting);
  4806 
  4807 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4808 
  4809 * the solver is now split into a safe and an unsafe part.
  4810 This should be invisible for the normal user, except that the
  4811 functions setsolver and addsolver have been renamed to setSolver and
  4812 addSolver; added safe_asm_full_simp_tac;
  4813 
  4814 
  4815 *** HOL ***
  4816 
  4817 * a generic induction tactic `induct_tac' which works for all datatypes and
  4818 also for type `nat';
  4819 
  4820 * a generic case distinction tactic `exhaust_tac' which works for all
  4821 datatypes and also for type `nat';
  4822 
  4823 * each datatype comes with a function `size';
  4824 
  4825 * patterns in case expressions allow tuple patterns as arguments to
  4826 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4827 
  4828 * primrec now also works with type nat;
  4829 
  4830 * recdef: a new declaration form, allows general recursive functions to be
  4831 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4832 
  4833 * the constant for negation has been renamed from "not" to "Not" to
  4834 harmonize with FOL, ZF, LK, etc.;
  4835 
  4836 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4837 infinite lists;
  4838 
  4839 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4840 
  4841 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4842 problems in commutative rings, using axiomatic type classes for + and *;
  4843 
  4844 * more examples in HOL/MiniML and HOL/Auth;
  4845 
  4846 * more default rewrite rules for quantifiers, union/intersection;
  4847 
  4848 * a new constant `arbitrary == @x.False';
  4849 
  4850 * HOLCF/IOA replaces old HOL/IOA;
  4851 
  4852 * HOLCF changes: derived all rules and arities
  4853   + axiomatic type classes instead of classes
  4854   + typedef instead of faking type definitions
  4855   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4856   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4857   + eliminated the types void, one, tr
  4858   + use unit lift and bool lift (with translations) instead of one and tr
  4859   + eliminated blift from Lift3.thy (use Def instead of blift)
  4860   all eliminated rules are derived as theorems --> no visible changes ;
  4861 
  4862 
  4863 *** ZF ***
  4864 
  4865 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4866 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4867 as ZF_cs addSIs [equalityI];
  4868 
  4869 
  4870 
  4871 New in Isabelle94-7 (November 96)
  4872 ---------------------------------
  4873 
  4874 * allowing negative levels (as offsets) in prlev and choplev;
  4875 
  4876 * super-linear speedup for large simplifications;
  4877 
  4878 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4879 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4880 FAIL); can suppress it using the command Delsimps (ex_simps @
  4881 all_simps); De Morgan laws are also now included, by default;
  4882 
  4883 * improved printing of ==>  :  ~:
  4884 
  4885 * new object-logic "Sequents" adds linear logic, while replacing LK
  4886 and Modal (thanks to Sara Kalvala);
  4887 
  4888 * HOL/Auth: correctness proofs for authentication protocols;
  4889 
  4890 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4891 examples on HOL/Auth);
  4892 
  4893 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4894 the rewriter and classical reasoner simultaneously;
  4895 
  4896 * function uresult no longer returns theorems in "standard" format;
  4897 regain previous version by: val uresult = standard o uresult;
  4898 
  4899 
  4900 
  4901 New in Isabelle94-6
  4902 -------------------
  4903 
  4904 * oracles -- these establish an interface between Isabelle and trusted
  4905 external reasoners, which may deliver results as theorems;
  4906 
  4907 * proof objects (in particular record all uses of oracles);
  4908 
  4909 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4910 
  4911 * "constdefs" section in theory files;
  4912 
  4913 * "primrec" section (HOL) no longer requires names;
  4914 
  4915 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4916 
  4917 
  4918 
  4919 New in Isabelle94-5
  4920 -------------------
  4921 
  4922 * reduced space requirements;
  4923 
  4924 * automatic HTML generation from theories;
  4925 
  4926 * theory files no longer require "..." (quotes) around most types;
  4927 
  4928 * new examples, including two proofs of the Church-Rosser theorem;
  4929 
  4930 * non-curried (1994) version of HOL is no longer distributed;
  4931 
  4932 
  4933 
  4934 New in Isabelle94-4
  4935 -------------------
  4936 
  4937 * greatly reduced space requirements;
  4938 
  4939 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4940 
  4941 * searchable theorem database (see the section "Retrieving theorems" on
  4942 page 8 of the Reference Manual);
  4943 
  4944 * new examples, including Grabczewski's monumental case study of the
  4945 Axiom of Choice;
  4946 
  4947 * The previous version of HOL renamed to Old_HOL;
  4948 
  4949 * The new version of HOL (previously called CHOL) uses a curried syntax
  4950 for functions.  Application looks like f a b instead of f(a,b);
  4951 
  4952 * Mutually recursive inductive definitions finally work in HOL;
  4953 
  4954 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4955 translates to the operator "split";
  4956 
  4957 
  4958 
  4959 New in Isabelle94-3
  4960 -------------------
  4961 
  4962 * new infix operator, addss, allowing the classical reasoner to
  4963 perform simplification at each step of its search.  Example:
  4964         fast_tac (cs addss ss)
  4965 
  4966 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4967 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4968 look like (a,b) instead of <a,b>;
  4969 
  4970 * PLEASE NOTE: CHOL will eventually replace HOL!
  4971 
  4972 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4973 It translates to the operator "split".  A new theory of integers is available;
  4974 
  4975 * In ZF, integer numerals now denote two's-complement binary integers.
  4976 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4977 
  4978 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4979 of the Axiom of Choice;
  4980 
  4981 
  4982 
  4983 New in Isabelle94-2
  4984 -------------------
  4985 
  4986 * Significantly faster resolution;
  4987 
  4988 * the different sections in a .thy file can now be mixed and repeated
  4989 freely;
  4990 
  4991 * Database of theorems for FOL, HOL and ZF.  New
  4992 commands including qed, qed_goal and bind_thm store theorems in the database.
  4993 
  4994 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4995 a given theory (thms_of), or find out what theory a theorem was proved in
  4996 (theory_of_thm);
  4997 
  4998 * Bugs fixed in the inductive definition and datatype packages;
  4999 
  5000 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5001 and HOL_dup_cs obsolete;
  5002 
  5003 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5004 have been removed;
  5005 
  5006 * Simpler definition of function space in ZF;
  5007 
  5008 * new results about cardinal and ordinal arithmetic in ZF;
  5009 
  5010 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5011 types;
  5012 
  5013 
  5014 $Id$